An absolute cavity pyrgeometer to measure the absolute outdoor longwave irradiance with traceability to international system of units, SI

NASA Astrophysics Data System (ADS)

Reda, Ibrahim; Zeng, Jinan; Scheuch, Jonathan; Hanssen, Leonard; Wilthan, Boris; Myers, Daryl; Stoffel, Tom

2012-03-01

This article describes a method of measuring the absolute outdoor longwave irradiance using an absolute cavity pyrgeometer (ACP), U.S. Patent application no. 13/049, 275. The ACP consists of domeless thermopile pyrgeometer, gold-plated concentrator, temperature controller, and data acquisition. The dome was removed from the pyrgeometer to remove errors associated with dome transmittance and the dome correction factor. To avoid thermal convection and wind effect errors resulting from using a domeless thermopile, the gold-plated concentrator was placed above the thermopile. The concentrator is a dual compound parabolic concentrator (CPC) with 180° view angle to measure the outdoor incoming longwave irradiance from the atmosphere. The incoming irradiance is reflected from the specular gold surface of the CPC and concentrated on the 11 mm diameter of the pyrgeometer's blackened thermopile. The CPC's interior surface design and the resulting cavitation result in a throughput value that was characterized by the National Institute of Standards and Technology. The ACP was installed horizontally outdoor on an aluminum plate connected to the temperature controller to control the pyrgeometer's case temperature. The responsivity of the pyrgeometer's thermopile detector was determined by lowering the case temperature and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The responsivity is then used to calculate the absolute atmospheric longwave irradiance with an uncertainty estimate (U95) of ±3.96 W m-2 with traceability to the International System of Units, SI. The measured irradiance was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the Interim World Infrared Standard Group, WISG. A total of 408 readings were collected over three different nights. The calculated irradiance measured by the ACP was 1.5 W/m2 lower than that measured by the two pyrgeometers that are traceable to WISG, with a standard deviation of ±0.7 W m-2. These results suggest that the ACP design might be used for addressing the need to improve the international reference for broadband outdoor longwave irradiance measurements.

Enhanced spectroscopic gas sensors using in-situ grown carbon nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Luca, A.; Cole, M. T.; Milne, W. I.

2015-05-11

In this letter, we present a fully complementary-metal-oxide-semiconductor (CMOS) compatible microelectromechanical system thermopile infrared (IR) detector employing vertically aligned multi-walled carbon nanotubes (CNT) as an advanced nano-engineered radiation absorbing material. The detector was fabricated using a commercial silicon-on-insulator (SOI) process with tungsten metallization, comprising a silicon thermopile and a tungsten resistive micro-heater, both embedded within a dielectric membrane formed by a deep-reactive ion etch following CMOS processing. In-situ CNT growth on the device was achieved by direct thermal chemical vapour deposition using the integrated micro-heater as a micro-reactor. The growth of the CNT absorption layer was verified through scanning electronmore » microscopy, transmission electron microscopy, and Raman spectroscopy. The functional effects of the nanostructured ad-layer were assessed by comparing CNT-coated thermopiles to uncoated thermopiles. Fourier transform IR spectroscopy showed that the radiation absorbing properties of the CNT adlayer significantly enhanced the absorptivity, compared with the uncoated thermopile, across the IR spectrum (3 μm–15.5 μm). This led to a four-fold amplification of the detected infrared signal (4.26 μm) in a CO{sub 2} non-dispersive-IR gas sensor system. The presence of the CNT layer was shown not to degrade the robustness of the uncoated devices, whilst the 50% modulation depth of the detector was only marginally reduced by 1.5 Hz. Moreover, we find that the 50% normalized absorption angular profile is subsequently more collimated by 8°. Our results demonstrate the viability of a CNT-based SOI CMOS IR sensor for low cost air quality monitoring.« less

Analytical and Experimental Characterization of a Linear-Array Thermopile Scanning Radiometer for Geo-Synchronous Earth Radiation Budget Applications

NASA Technical Reports Server (NTRS)

Sorensen, Ira J.

1998-01-01

The Thermal Radiation Group, a laboratory in the department of Mechanical Engineering at Virginia Polytechnic Institute and State University, is currently working towards the development of a new technology for cavity-based radiometers. The radiometer consists of a 256-element linear-array thermopile detector mounted on the wall of a mirrored wedgeshaped cavity. The objective of this research is to provide analytical and experimental characterization of the proposed radiometer. A dynamic end-to-end opto-electrothermal model is developed to simulate the performance of the radiometer. Experimental results for prototype thermopile detectors are included. Also presented is the concept of the discrete Green's function to characterize the optical scattering of radiant energy in the cavity, along with a data-processing algorithm to correct for the scattering. Finally, a parametric study of the sensitivity of the discrete Green's function to uncertainties in the surface properties of the cavity is presented.

Compact Focal Plane Assembly for Planetary Science

NASA Technical Reports Server (NTRS)

Brown, Ari; Aslam, Shahid; Huang, Wei-Chung; Steptoe-Jackson, Rosalind

2013-01-01

A compact radiometric focal plane assembly (FPA) has been designed in which the filters are individually co-registered over compact thermopile pixels. This allows for construction of an ultralightweight and compact radiometric instrument. The FPA also incorporates micromachined baffles in order to mitigate crosstalk and low-pass filter windows in order to eliminate high-frequency radiation. Compact metal mesh bandpass filters were fabricated for the far infrared (FIR) spectral range (17 to 100 microns), a game-changing technology for future planetary FIR instruments. This fabrication approach allows the dimensions of individual metal mesh filters to be tailored with better than 10- micron precision. In contrast, conventional compact filters employed in recent missions and in near-term instruments consist of large filter sheets manually cut into much smaller pieces, which is a much less precise and much more labor-intensive, expensive, and difficult process. Filter performance was validated by integrating them with thermopile arrays. Demonstration of the FPA will require the integration of two technologies. The first technology is compact, lightweight, robust against cryogenic thermal cycling, and radiation-hard micromachined bandpass filters. They consist of a copper mesh supported on a deep reactive ion-etched silicon frame. This design architecture is advantageous when constructing a lightweight and compact instrument because (1) the frame acts like a jig and facilitates filter integration with the FPA, (2) the frame can be designed so as to maximize the FPA field of view, (3) the frame can be simultaneously used as a baffle for mitigating crosstalk, and (4) micron-scale alignment features can be patterned so as to permit high-precision filter stacking and, consequently, increase the filter bandwidth and sharpen the out-of-band rolloff. The second technology consists of leveraging, from another project, compact and lightweight Bi0.87Sb0.13/Sb arrayed thermopiles. These detectors consist of 30-layer thermopiles deposited in series upon a silicon nitride membrane. At 300 K, the thermopile arrays are highly linear over many orders of magnitude of incident IR power, and have a reported specific detectivity that exceeds the requirements imposed on future mission concepts. The bandpass filter array board is integrated with a thermopile array board by mounting both boards on a machined aluminum jig.

Thermal Characteristics of Pyranometers and Pyrgeometers in Atmosphere-Surface Energetic Measurements

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee; Einaudi, Franco (Technical Monitor)

2000-01-01

Since the introduction of thermopile, pyranometers (solar, e.g., 0.3 - 3.0 microns) and pyrgeometers (terrestrial, e.g., 4 - 50 microns) have become instruments commonly used for measuring the broadband hemispherical irradiances at the surface in a long-term, monitoring mode for decades. These commercially available radiometers have been manufactured in several countries such as from the United States, Asia, and Europe, and are generally reliable and economical. These worldwide distributions of surface measurements become even more important in the era of Earth remote sensing in studying climate change. However, recent studies from field campaigns have pointed out that erroneous factors (e.g., temperature gradients between the filter dome and detector, emissivity of the thermopile) are responsible for the unacceptable level of uncertainty (e.g., 20 W/sq m). It is best to utilize an energy balance equation to describe the thermal dome effect of pyranometers and pyrgeometers. Therefore, quality of pyranometer and pyrgeometer measurements can be improved largely by applying proper knowledge of the thermal parameters affecting the operation of the thermopile systems. Data correction procedure and algorithm will be presented and discussed.

Removing nickel from nickel-coated carbon fibers

NASA Astrophysics Data System (ADS)

Hardianto, A.; Hertleer, C.; De Mey, G.; Van Langenhove, L.

2017-10-01

Conductive fibers/yarns are one of the most important materials for smart textiles because of their electrically conductive functionality combined with flexibility and light weight. They can be applied in many fields such as the medical sector, electronics, sensors and even as thermoelectric generators. Temperature sensors, for example, can be made using the thermocouple or thermopile principle which usually uses two different metal wires that can produce a temperature-dependent voltage. However, if metal wires are inserted into a textile structure, they will decrease the flexibility properties of the textile product. Nickel-coated Carbon Fiber (NiCF), a conductive textile yarn, has a potential use as a textile-based thermopile if we can create an alternating region of carbon and nickel along the fiber which in turn it can be used for substituting the metallic thermopile. The idea was to remove nickel from NiCF in order to obtain a yarn that contains alternating zones of carbon and nickel. Due to no literature reporting on how to remove nickel from NiCF, in this paper we investigated some chemicals to remove nickel from NiCF.

A Novel Non-Intrusive Method to Resolve the Thermal-Dome-Effect of Pyranometers: Radiometric Calibration and Implications

NASA Technical Reports Server (NTRS)

Ji, Qiang; Tsay, Si-Chee; Lau, K. M.; Hansell, R. A.; Butler, J. J.; Cooper, J. W.

2011-01-01

Traditionally the calibration equation for pyranometers assumes that the measured solar irradiance is solely proportional to the thermopile's output voltage; therefore only a single calibration factor is derived. This causes additional measurement uncertainties because it does not capture sufficient information to correctly account for a pyranometer's thermal effect. In our updated calibration equation, temperatures from the pyranometer's dome and case are incorporated to describe the instrument's thermal behavior, and a new set of calibration constants are determined, thereby reducing measurement uncertainties. In this paper, we demonstrate why a pyranometer's uncertainty using the traditional calibration equation is always larger than a-few-percent, but with the new approach can become much less than 1% after the thermal issue is resolved. The highlighted calibration results are based on NIST-traceable light sources under controlled laboratory conditions. The significance of the new approach lends itself to not only avoiding the uncertainty caused by a pyranometer's thermal effect but also the opportunity to better isolate and characterize other instrumental artifacts, such as angular response and non-linearity of the thermopile, to further reduce additional uncertainties. We also discuss some of the implications, including an example of how the thermal issue can potentially impact climate studies by evaluating aerosol's direct-radiative effect using field measurements with and without considering the pyranometer's thermal effect. The results of radiative transfer model simulation show that a pyranometer's thermal effect on solar irradiance measurements at the surface can be translated into a significant alteration of the calculated distribution of solar energy inside the column atmosphere.

A Novel Nonintrusive Method to Resolve the Thermal Dome Effect of Pyranometers: Radiometric Calibration and Implications

NASA Technical Reports Server (NTRS)

Ji. Q.; Tsay, S.-C.; Lau, K. M.; Hansell, R. A.; Butler, J. J.; Cooper, J. W.

2011-01-01

Traditionally the calibration equation for pyranometers assumes that the measured solar irradiance is solely proportional to the thermopile s output voltage; therefore, only a single calibration factor is derived. This causes additional measurement uncertainties because it does not capture sufficient information to correctly account for a pyranometer s thermal effect. In our updated calibration equation, temperatures from the pyranometer's dome and case are incorporated to describe the instrument's thermal behavior, and a new set of calibration constants are determined, thereby reducing measurement uncertainties. In this paper, we demonstrate why a pyranometer's uncertainty using the traditional calibration equation is always larger than a few percent, but with the new approach can become much less than 1% after the thermal issue is resolved. The highlighted calibration results are based on NIST traceable light sources under controlled laboratory conditions. The significance of the new approach lends itself to not only avoiding the uncertainty caused by a pyranometer's thermal effect but also the opportunity to better isolate and characterize other instrumental artifacts, such as angular response and nonlinearity of the thermopile, to further reduce additional uncertainties. We also discuss some of the implications, including an example of how the thermal issue can potentially impact climate studies by evaluating aerosol s direct radiative effect using field measurements with and without considering the pyranometer s thermal effect. The results of radiative transfer model simulation show that a pyranometer s thermal effect on solar irradiance measurements at the surface can be translated into a significant alteration of the calculated distribution of solar energy inside the column atmosphere.

Characterization and optimization of polycrystalline Si70%Ge30% for surface micromachined thermopiles in human body applications

NASA Astrophysics Data System (ADS)

Wang, Ziyang; Fiorini, Paolo; Leonov, Vladimir; Van Hoof, Chris

2009-09-01

This paper presents the material characterization methods, characterization results and the optimization scheme for polycrystalline Si70%Ge30% (poly-SiGe) from the perspective of its application in a surface micromachined thermopile. Due to its comparative advantages, such as lower thermal conductivity and ease of processing, over other materials, poly-SiGe is chosen to fabricate a surface micromachined thermopile and eventually a wearable thermoelectric generator (TEG) to be used on a human body. To enable optimal design of advanced thermocouple microstructures, poly-SiGe sample materials prepared by two different techniques, namely low-pressure chemical vapor deposition (LPCVD) with in situ doping and rapid thermal chemical vapor deposition (RTCVD) with ion implantation, have been characterized. Relevant material properties, including electrical resistivity, Seebeck coefficient, thermal conductivity and specific contact resistance, have been reported. For the determination of thermal conductivity, a novel surface-micromachined test structure based on the Seebeck effect is designed, fabricated and measured. Compared to the traditional test structures, it is more advantageous for sample materials with a relatively large Seebeck coefficient, such as poly-SiGe. Based on the characterization results, a further optimization scheme is suggested to allow independent respective optimization of the figure of merit and the specific contact resistance.

Characterization of Thermal Parameters for Improving Pyranometer and Pyrgeometer Measurements

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee; Jhabvala, Murzy D.; Ji, Qiang; Rapshun, David; Shu, Peter K.

2000-01-01

Since the introduction of thermopile, pyranometers (solar, e.g., 0.3-3.0 micrometers) and pyrgeometers (terrestrial, e.g., 4-50 micrometers) have become instruments commonly used for measuring the broadband hemispherical irradiances at the surface in a long-term, monitoring mode for decades. These commercially available radiometers have been manufactured in several countries such as from the United States, Asia, and Europe, and are generally reliable and economical. These worldwide distributions of surface measurements become even more important in the era of Earth remote sensing in studying climate change. However, recent studies from field campaigns have pointed out that erroneous factors (e.g., temperature gradients between the filter dome and detector, emissivity of the thermopile) are responsible for the unacceptable level of uncertainty (e.g., 20 W m(exp -2)). Using a newly developed instrument of Quantum Well Infrared Photodetector (QWTP), we have characterized the brightness temperature fields of pyranometers and pyrgeometers under various sky conditions. The QWIP is based on the superlattice (GaAs/AlGaAs) technology and has a noise equivalent temperature (NEAT) less than 0.1 K. The quality of pyranometer and pyrgeometer measure- ments can be improved largely by applying proper knowledge of the thermal parameters affecting the operation of the thermopile systems. Data correction procedure and algorithm will be presented and discussed.

Thermoacoustic couple

DOEpatents

Wheatley, J.C.; Swift, G.W.; Migliori, A.

1983-10-04

An apparatus and method for determining acoustic power density level and its direction in a fluid using a single sensor are disclosed. The preferred embodiment of the apparatus, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

Method of measuring reactive acoustic power density in a fluid

DOEpatents

Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

1985-01-01

A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

Method of measuring reactive acoustic power density in a fluid

DOEpatents

Wheatley, J.C.; Swift, G.W.; Migliori, A.

1985-09-03

A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas. 5 figs.

THERMO-ELECTRIC GENERATOR

DOEpatents

Jordan, K.C.

1958-07-22

The conversion of heat energy into electrical energy by a small compact device is descrtbed. Where the heat energy is supplied by a radioactive material and thermopIIes convert the heat to electrical energy. The particular battery construction includes two insulating discs with conductive rods disposed between them to form a circular cage. In the center of the cage is disposed a cup in which the sealed radioactive source is located. Each thermopile is formed by connecting wires from two adjacent rods to a potnt on an annular ring fastened to the outside of the cup, the ring having insulation on its surface to prevent electrica1 contact with the thermopiles. One advantage of this battery construction is that the radioactive source may be inserted after the device is fabricated, reducing the radiation hazard to personnel assembling the battery.

Triaxial thermopile array geo-heat-flow sensor

DOEpatents

Carrigan, C.R.; Hardee, H.C.; Reynolds, G.D.; Steinfort, T.D.

1990-01-01

A triaxial thermopile array geothermal heat flow sensor is designed to measure heat flow in three dimensions in a reconstituted or unperturbed subsurface regime. Heat flow can be measured in conductive or permeable convective media. The sensor may be encased in protective pvc tubing and includes a plurality of thermistors and an array of heat flow transducers produce voltage proportional to heat flux along the subsurface regime and permit direct measurement of heat flow in the subsurface regime. The presence of the thermistor array permits a comparison to be made between the heat flow estimates obtained from the transducers and heat flow calculated using temperature differences and Fourier's Law. The device is extremely sensitive with an accuracy of less than 0.1 Heat Flow Units (HFU) and may be used for long term readings. 6 figs.

A new and inexpensive pyranometer for the visible spectral range.

PubMed

Martínez, Miguel A; Andújar, José M; Enrique, Juan M

2009-01-01

This paper presents the design, construction and testing of a new photodiode-based pyranometer for the visible spectral range (approx. 400 to 750 nm), whose principal characteristics are: accuracy, ease of connection, immunity to noise, remote programming and operation, interior temperature regulation, cosine error minimisation and all this at a very low cost, tens of times lower than that of commercial thermopile-based devices. This new photodiode-based pyranometer overcomes traditional problems in this type of device and offers similar characteristics to those of thermopile-based pyranometers and, therefore, can be used in any installation where reliable measurement of solar irradiance is necessary, especially in those where cost is a deciding factor in the choice of a meter. This new pyranometer has been registered in the Spanish Patent and Trademark Office under the number P200703162.

A New and Inexpensive Pyranometer for the Visible Spectral Range

PubMed Central

Martínez, Miguel A.; Andújar, José M.; Enrique, Juan M.

2009-01-01

This paper presents the design, construction and testing of a new photodiode-based pyranometer for the visible spectral range (approx. 400 to 750 nm), whose principal characteristics are: accuracy, ease of connection, immunity to noise, remote programming and operation, interior temperature regulation, cosine error minimisation and all this at a very low cost, tens of times lower than that of commercial thermopile-based devices. This new photodiode-based pyranometer overcomes traditional problems in this type of device and offers similar characteristics to those of thermopile-based pyranometers and, therefore, can be used in any installation where reliable measurement of solar irradiance is necessary, especially in those where cost is a deciding factor in the choice of a meter. This new pyranometer has been registered in the Spanish Patent and Trademark Office under the number P200703162. PMID:22408545

Triaxial thermopile array geo-heat-flow sensor

DOEpatents

Carrigan, Charles R.; Hardee, Harry C.; Reynolds, Gerald D.; Steinfort, Terry D.

1992-01-01

A triaxial thermopile array geothermal heat flow sensor is designed to measure heat flow in three dimensions in a reconstituted or unperturbed subsurface regime. Heat flow can be measured in conductive or permeable convective media. The sensor may be encased in protective pvc tubing and includes a plurality of thermistors and an array of heat flow transducers arranged in a vertical string. The transducers produce voltage proportional to heat flux along the subsurface regime and permit direct measurement of heat flow in the subsurface regime. The presence of the thermistor array permits a comparison to be made between the heat flow estimates obtained from the transducers and heat flow calculated using temperature differences and Fourier's Law. The device is extremely sensitive with an accuracy of less than 0.1 Heat Flow Units (HFU) and may be used for long term readings.

High- and Mid-temperature Superconducting Sensors for Far IR/Sub-mm Applications in Space

NASA Technical Reports Server (NTRS)

Lakew, Brook; Brasunas, J. C.

2004-01-01

In this review paper an overview of the potential applications of high Tc (approx. 90 K) superconductors (HTS) and mid-Tc (approx. 39 K) superconductors (MTS) thin films in far IR/Sub-mm thermal detectors is presented. HTSs (YBCO, GdBCO etc.) were discovered in the late 80s while superconductivity in MgB2, an MTS, was discovered in 2001. The sharp transition in transport properties of HTS has allowed the fabrication of composite infrared thermal detectors (bolometers) with better figures of merit than thermopile detectors - thermopiles are currently on board the CIRS instrument on the Cassini mission to Saturn. The potential for developing even more sensitive sensors for IR/Sub-mm applications using MgB2 thin films is assessed. Current MgB2 thin film deposition techniques and film quality are reviewed.

Ionic thermoelectric gating organic transistors

PubMed Central

Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

2017-01-01

Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (∼100 μV K−1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (∼10,000 μV K−1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins. PMID:28139738

Accuracy of silicon versus thermopile radiometers for daily and monthly integrated total hemispherical solar radiation

NASA Astrophysics Data System (ADS)

Stoffel, Thomas L.; Myers, Daryl R.

2010-08-01

Measurement stations for solar radiation resource assessment data are expensive and labor intensive. For this reason, long-term solar radiation measurements are not widely available. Growing interest in solar renewable energy systems has generated a great number of questions about the quality of data obtained from inexpensive silicon photodiode radiometers versus costly thermopile radiometers. We analyze a year of daily total and monthly mean global horizontal irradiance measurements derived from 1-minute averages of 3-second samples of pyranometer signals. The data were collected simultaneously from both types of radiometers at the Solar Radiation Research Laboratory (SRRL) operated by the National Renewable Energy Laboratory in Golden, Colorado. All broadband radiometers in service at SRRL are calibrated annually using an outdoor method with reference radiometers traceable to the World Radiometric Reference. We summarized the data by daily total and monthly mean daily total amounts of solar radiation. Our results show that systematic and random errors (identified in our outdoor calibration process) in each type of radiometer cancel out over periods of one day or more. Daily total and mean monthly daily total solar energy measured by the two pyranometer types compare within 1% to 2%. The individual daily variations among different models of thermopile radiometers may be up to twice as large, up to +/-5%, being highest in the winter (higher average solar zenith angle conditions) and lowest in summer, consistent with the lower solar zenith angle conditions.

Noncontact localized internal infrared radiation measurement using an infrared point detector

NASA Astrophysics Data System (ADS)

Hisaka, Masaki

2017-12-01

The techniques for temperature measurement within the human body are important for clinical applications. A method for noncontact local infrared (IR) radiation measurements was investigated deep within an object to simulate how the core human body temperature can be obtained. To isolate the IR light emitted from a specific area within the object from the external noise, the radiating IR light was detected using an IR point detector, which comprises a pinhole and a thermopile positioned at an imaging relation with the region of interest within the object. The structure of the helical filament radiating IR light inside a light bulb was thermally imaged by scanning the bulb in two dimensions. Moreover, this approach was used to effectively measure IR light in the range of human body temperature using a glass plate placed in front of the heat source, mimicking the ocular fundus.

Noncontact localized internal infrared radiation measurement using an infrared point detector

NASA Astrophysics Data System (ADS)

Hisaka, Masaki

2018-06-01

The techniques for temperature measurement within the human body are important for clinical applications. A method for noncontact local infrared (IR) radiation measurements was investigated deep within an object to simulate how the core human body temperature can be obtained. To isolate the IR light emitted from a specific area within the object from the external noise, the radiating IR light was detected using an IR point detector, which comprises a pinhole and a thermopile positioned at an imaging relation with the region of interest within the object. The structure of the helical filament radiating IR light inside a light bulb was thermally imaged by scanning the bulb in two dimensions. Moreover, this approach was used to effectively measure IR light in the range of human body temperature using a glass plate placed in front of the heat source, mimicking the ocular fundus.

Application of a scattered-light radiometric power meter.

PubMed

Caron, James N; DiComo, Gregory P; Ting, Antonio C; Fischer, Richard P

2011-04-01

The power measurement of high-power continuous-wave laser beams typically calls for the use of water-cooled thermopile power meters. Large thermopile meters have slow response times that can prove insufficient to conduct certain tests, such as determining the influence of atmospheric turbulence on transmitted beam power. To achieve faster response times, we calibrated a digital camera to measure the power level as the optical beam is projected onto a white surface. This scattered-light radiometric power meter saves the expense of purchasing a large area power meter and the required water cooling. In addition, the system can report the power distribution, changes in the position, and the spot size of the beam. This paper presents the theory of the scattered-light radiometric power meter and demonstrates its use during a field test at a 2.2 km optical range. © 2011 American Institute of Physics

A MEMS Infrared Thermopile Fabricated from Silicon-On-Insulator with Phononic Crystal Structures and Carbon Nanotube Absorption Layer

NASA Astrophysics Data System (ADS)

Gray, Kory Forrest

The goal of this project was to examine the possibility of creating a novel thermal infrared detector based on silicon CMOS technology that has been enhanced by the latest nano-engineering discoveries. Silicon typically is not thought as an efficient thermoelectric material. However recent advancements in nanotechnology have improved the potential for a highly sensitive infrared detector based on nano-structured silicon. The thermal conductivity of silicon has been shown to be reduced from 150 W/mK down to 60 W/mK just by decreasing the scale of the silicon from bulk down to the sub-micron scale. Further reduction of the thermal conductivity has been shown by patterning silicon with a phonon crystal structure which has been reported to have thermal conductivities down to 10 W/mK. The phonon crystal structure consists of a 2D array of holes that are etched into the silicon. The size and pitch of the holes are on the order of the mean free path of the phonons in silicon which is approximately 200-500nm. This particular device had 200nm holes on a 400nm pitch. The Seebeck coefficient of silicon can also be enhanced by the reduction of the material from the bulk to sub-micron scale and with degenerate level doping. The combination of decreased thermal conductivity and increased Seebeck coefficient allow silicon to be a promising material for thermoelectric infrared detectors. The highly doped silicon is desired to reduce the electrical resistance of the device. The low electrical resistance is required to reduce the Johnson noise of the device which is the dominant noise source for most thermal detectors. This project designed a MEMS thermopile using a silicon-on-insulator substrate, and a CMOS compatible process. The basic thermopile consists of a silicon dioxide membrane with phononic crystal patterned silicon thermocouples around the edges of the membrane. Vertical aligned, multi-walled, carbon nanotubes were used as the infrared absorption layer. A MEMS thermoelectric detector with a D* of 3 * 107 cm Hz 0.5/W was demonstrated with a time response of 3-10 milliseconds. With this initial research, it is possible to improve the D* to the high 108 cm Hz 0.5/W range by slightly changing the design of the thermopile and patterning the absorption layer.

Upcoming planetary missions and the applicability of high temperature superconductor bolometers

NASA Technical Reports Server (NTRS)

Brasunas, J.; Kunde, V.; Moseley, H.; Lakew, B.

1991-01-01

Planetary missions to Mars and beyond can last 11 years and longer, making impractical the use of stored cryogens. Passive radiative coolers and single-stage mechanical coolers remain possibilities. Cassini and Comet Rendezvous/Asteroid Fly-by (CRAF), both using the newly developed Mariner Mark 2 spacecraft, will be the next outer planet missions after Galileo; they are intended to provide information on the origin and evolution of the solar system. CRAF is slated for a 1994 launch. Cassini was chosen by ESA and will be launched by a Titan 4/Centaur in 1996. It will fly by Jupiter in 2000, inject an ESA-supplied probe into Titan in 2002, and take data in Saturn's orbit from 2002 to 2006. NASA/Goddard is currently developing a prototype Fourier transform spectrometer, the Composite Infrared Spectrometer (CIRS), for the Cassini mission. The baseline infrared detectors for CIRS are HgCdTe to 16 microns and Schwarz-type thermopiles from 16 to 1000 microns. The far infrared focal plane could be switched from thermopiles to high temperature superconductor (HTS) bolometers between now and 1996. An HTS bolometer could be built using the kinetic inductance effect, or the sharp resistance change at the transition. The transition-edge bolometer is more straightforward to implement, and initial efforts at NASA/Goddard are directed to that device. A working device was made and tested in early 1989. It also has somewhat elevated noise levels below 100 Hz. Upcoming efforts will center on reducing the time constant of the HTS bolometer by attempting to deposit an HTS film on a diamond substrate, and by thinning SrTiO3 substrates. Attempts will be made to improve the film quality to reduce the 1/4 noise level, and to improve the thermal isolation to increase the bolometer sensitivity. An attempt is being made to deposit good-quality HTS films on diamond films using a metal-organic chemical vapor deposition (MOCVD) technique.

Upcoming planetary missions and the applicability of high temperature superconductor bolometers

NASA Technical Reports Server (NTRS)

Brasunas, J.; Kunde, V.; Moseley, H.; Lakew, B.

1990-01-01

Planetary missions to Mars and beyond can last 11 years and longer, making impractical the use of stored cryogens. Passive radiative coolers and single-stage mechanical coolers remain possibilities. CRAF and CASSINI, both using the newly developed Mariner Mark 2 spacecraft, will be the next outer planet missions after Galileo; they are intended to provide information on the origin and evolution of the solar system. CRAF is a cometary rendezvous mission slated for a 1994 launch. CASSINI has been chosen by ESA and will be launched by a Titan 4/Centaur in 1996. It will fly by Jupiter in 2000, inject an ESA-supplied probe into Titan in 2002, and take data in Saturn orbit from 2002 to 2006. NASA/Goddard is currently developing a prototype Fourier transform spectrometer (CIRS) that will be proposed for the CASSINI mission. The baseline infrared detectors for CIRS are HgCdTe to 16 microns and Schwarz-type thermopiles from 16 to 1000 microns. The far infrared focal plane could be switched from thermopiles to high temperature superconductor (HTS) bolometers between now and 1996. An HTS bolometer could be built using the kinetic inductance effect, or the sharp resistance change at the transition. The transition-edge bolometer is more straightforward to implement and initial efforts at NASA/Goddard are directed to that device. A working device was made and tested in early 1989. It also has somewhat elevated noise levels below 100 Hz. Upcoming efforts will center on reducing the time constant of the HTS bolometer by attempting to deposit an HTS film on a diamond substrate, and by thinning SrTiO3 substrates. Attempts will be made to improve the film quality to reduce th 1/f noise level, and to improve the thermal isolation to increase the bolometer sensitivity. An attempt is being made to deposit good-quality HTS films on diamond films using an MOCVD technique.

On the Dome Effect of Flux Radiometers to Radiative Forcing

NASA Technical Reports Server (NTRS)

Tsay, S.-C.; Ji, Q.

1999-01-01

Since the introduction of thermopile, pyranometers (solar, e.g., 0.3-3.0 microns) and pyrgeometers (terrestrial, e.g., 4-50 microns) have become instruments commonly used for measuring the broadband hemispherical irradiances at the surface in a long-term, monitoring mode for decades. These commercially available radiometers have been manufactured in several countries such as from the United States, Asia, and Europe, and are generally reliable and economical. These worldwide distributions of surface measurements become even more important in the era of Earth remote sensing in studying climate forcing. However, recent studies from field campaigns have pointed out that erroneous factors (e.g., temperature gradients between the filter dome and detector, emissivity of the thermopile) are responsible for the unacceptable level of uncertainty (e.g., 10-20 W/square Meter). Using a newly developed instrument of Quantum Well Infrared Photodetector (QWIP), we have characterized the brightness temperature fields of pyranometers and pyrgeometers under various sky conditions. The QWIP is based on the superlattice (GaAs/AlGaAs) technology and has a noise equivalent temperature (NE delta T) less than 0.1 K. The quality of pyranometer and pyrgeometer measurements can be improved largely by applying proper knowledge of the thermal parameters affecting the operation of the thermopile systems. For example, we show a method to determine the "dome factor" (the longwave emission divided by the longwave transmission of a pyrgeometer dome) from field measurements. The results show, and are verified independently by the QWIP, that our dome factors of 0.59 and 0.90 are much smaller than the value of 4.0 assumed by the WMO. Data correction procedure and algorithm will be presented and discussed.

On the Dome Effect of Flux Radiometers to Radiative Forcing

NASA Technical Reports Server (NTRS)

Tsay, S.-C.; Ji, Q.

1999-01-01

Since the introduction of thermopile, pyranometers (solar, e.g., 0.3-3.0 micrometers) and pyrgeometers (terrestrial, e.g., 4-50 micrometers) have become instruments commonly used for measuring the broadband hemispherical irradiances at the surface in a long-term, monitoring mode for decades. These commercially available radiometers have been manufactured in several countries such as from the United States, Asia, and Europe, and are generally reliable and economical. These worldwide distributions of surface measurements become even more important in the era of Earth remote sensing in studying climate forcing. However, recent studies from field campaigns have pointed out that erroneous factors (e.g., temperature gradients between the filter dome and detector, emissivity of the thermopile) are responsible for the unacceptable level of uncertainty (e.g., 10-20 W m (exp -2)). Using a newly developed instrument of Quantum Well Infrared Photodetector (QWIP), we have characterized the brightness temperature fields of pyranometers and pyrgeometers under various sky conditions. The QWIP is based on the superlattice (GaAs/AlGaAs) technology and has a noise equivalent temperature (NE delta T) less than 0.1 K. The quality of pyranometer and pyrgeometer measurements can be improved largely by applying proper knowledge of the thermal parameters affecting the operation of the thermopile systems. For example, we show a method to determine the "dome factor" (the longwave emission divided by the longwave transmission of a pyrgeometer dome) from field measurements. The results show, and are verified independently by the QWIP, that our dome factors of 0.59 and 0.90 are much smaller than the value of 4.0 assumed by the WMO (World Meteorological Organization). Data correction procedure and algorithm will be presented and discussed.

Human location estimation using thermopile array sensor

NASA Astrophysics Data System (ADS)

Parnin, S.; Rahman, M. M.

2017-11-01

Utilization of Thermopile sensor at an early stage of human detection is challenging as there are many things that produce thermal heat other than human such as electrical appliances and animals. Therefrom, an algorithm for early presence detection has been developed through the study of human body temperature behaviour with respect to the room temperature. The change in non-contact detected temperature of human varied according to body parts. In an indoor room, upper parts of human body change up to 3°C whereas lower part ranging from 0.58°C to 1.71°C. The average changes in temperature of human is used as a conditional set-point value in the program algorithm to detect human presence. The current position of human and its respective angle is gained when human is presence at certain pixels of Thermopile’s sensor array. Human position is estimated successfully as the developed sensory system is tested to the actuator of a stand fan.

Micromachined Thermoelectric Sensors and Arrays and Process for Producing

NASA Technical Reports Server (NTRS)

Foote, Marc C. (Inventor); Jones, Eric W. (Inventor); Caillat, Thierry (Inventor)

2000-01-01

Linear arrays with up to 63 micromachined thermopile infrared detectors on silicon substrates have been constructed and tested. Each detector consists of a suspended silicon nitride membrane with 11 thermocouples of sputtered Bi-Te and Bi-Sb-Te thermoelectric elements films. At room temperature and under vacuum these detectors exhibit response times of 99 ms, zero frequency D* values of 1.4 x 10(exp 9) cmHz(exp 1/2)/W and responsivity values of 1100 V/W when viewing a 1000 K blackbody source. The only measured source of noise above 20 mHz is Johnson noise from the detector resistance. These results represent the best performance reported to date for an array of thermopile detectors. The arrays are well suited for uncooled dispersive point spectrometers. In another embodiment, also with Bi-Te and Bi-Sb-Te thermoelectric materials on micromachined silicon nitride membranes, detector arrays have been produced with D* values as high as 2.2 x 10(exp 9) cm Hz(exp 1/2)/W for 83 ms response times.

A Radiation Hardened by Design CMOS ASIC for Thermopile Readouts

NASA Technical Reports Server (NTRS)

Quilligan, G.; Aslam, S.; DuMonthier, J.

2012-01-01

A radiation hardened by design (RHBD) mixed-signal application specific integrated circuit (ASIC) has been designed for a thermopile readout for operation in the harsh Jovian orbital environment. The multi-channel digitizer (MCD) ASIC includes 18 low noise amplifier channels which have tunable gain/filtering coefficients, a 16-bit sigma-delta analog-digital converter (SDADC) and an on-chip controller. The 18 channels, SDADC and controller were designed to operate with immunity to single event latchup (SEL) and to at least 10 Mrad total ionizing dose (TID). The ASIC also contains a radiation tolerant 16-bit 20 MHz Nyquist ADC for general purpose instrumentation digitizer needs. The ASIC is currently undergoing fabrication in a commercial 180 nm CMOS process. Although this ASIC was designed specifically for the harsh radiation environment of the NASA led JEO mission it is suitable for integration into instrumentation payloads 011 the ESA JUICE mission where the radiation hardness requirements are slightly less stringent.

Detecting drift bias and exposure errors in solar and photosynthetically active radiation data

USDA-ARS?s Scientific Manuscript database

All-black thermopile pyranometers are commonly used to measure solar radiation. Ensuring that the sensors are stable and free of drift is critical to accurately measure small variations in global solar irradiance (K'), which is a potential driver of changes in surface temperature. We demonstrate tha...

Magnon-drag thermopile.

PubMed

Costache, Marius V; Bridoux, German; Neumann, Ingmar; Valenzuela, Sergio O

2011-12-18

Thermoelectric effects in spintronics are gathering increasing attention as a means of managing heat in nanoscale structures and of controlling spin information by using heat flow. Thermal magnons (spin-wave quanta) are expected to play a major role; however, little is known about the underlying physical mechanisms involved. The reason is the lack of information about magnon interactions and of reliable methods to obtain it, in particular for electrical conductors because of the intricate influence of electrons. Here, we demonstrate a conceptually new device that enables us to gather information on magnon-electron scattering and magnon-drag effects. The device resembles a thermopile formed by a large number of pairs of ferromagnetic wires placed between a hot and a cold source and connected thermally in parallel and electrically in series. By controlling the relative orientation of the magnetization in pairs of wires, the magnon drag can be studied independently of the electron and phonon-drag thermoelectric effects. Measurements as a function of temperature reveal the effect on magnon drag following a variation of magnon and phonon populations. This information is crucial to understand the physics of electron-magnon interactions, magnon dynamics and thermal spin transport.

Passive exposure of Earth radiation budget experiment components. LDEF experiment AO-147: Post-flight examinations and tests

NASA Technical Reports Server (NTRS)

Hickey, John R.

1992-01-01

The flight spare sensors of the Earth Radiation Budget (ERB) experiment of the Nimbus 6 and 7 missions were flown aboard the LDEF. The preliminary post retrieval examination and test results are presented here for the sensor windows and filters, the thermopile sensors and a cavity radiometer.

Measurements of convective and radiative heating in wildland fires

Treesearch

David Frankman; Brent W. Webb; Bret W. Butler; Daniel Jimenez; Jason M. Forthofer; Paul Sopko; Kyle S. Shannon; J. Kevin Hiers; Roger D. Ottmar

2012-01-01

Time-resolved irradiance and convective heating and cooling of fast-response thermopile sensors were measured in 13 natural and prescribed wildland fires under a variety of fuel and ambient conditions. It was shown that a sensor exposed to the fire environment was subject to rapid fluctuations of convective transfer whereas irradiance measured by a windowed sensor was...

10 CFR Appendix E to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Water Heaters

Code of Federal Regulations, 2014 CFR

2014-01-01

... following: a. A thermopile b. Calibrated resistance thermometers c. Precision thermometers d. Calibrated... is used, it shall be made from calibrated thermocouple wire taken from a single spool. Extension wires to the recording device shall also be made from that same spool. 3.2.6 Time Constant. The time...

HRR Upgrade to mass loss calorimeter and modified Schlyter test for FR Wood

Treesearch

Mark A. Dietenberger; Charles R. Boardman

2013-01-01

Enhanced Heat Release Rate (HRR) methodology has been extended to the Mass Loss Calorimeter (MLC) and the Modified Schlyter flame spread test to evaluate fire retardant effectiveness used on wood based materials. Modifications to MLC include installation of thermopile on the chimney walls to correct systematic errors to the sensible HRR calculations to account for...

Nimbus-6 and -7 Earth Radiation Budget (ERB) sensor details and component tests

NASA Technical Reports Server (NTRS)

Soule, H. V.; Kyle, H. L.; Jacobowitz, H.; Hickey, J.

1983-01-01

Construction details and operating characteristics are described for the thermopile (used in the solar and fixed-Earth channels) and the pyroelectric detector (used in the Earth-scanning channels) carried on the Nimbus 6 and the Nimbus 7 satellites for gathering Earth radiation budget data. Properties of the black coating for the detectors, and sensor testing and calibration are discussed.

Effects of Ionization-Induced Smog on Air Chemistry.

DTIC Science & Technology

1987-01-30

After leaving the monochromater, the beam was incident on the window of a HgCdTe Detector ( Infrared Assoc., Inc.), hereafter referred to as the...regulated power supply (Model 68735). The intensity of infrared light produced was measured by a thermopile detector (ORIEL Model 7102), hereafter...process measurements from the bolometer and detector and to control the stepper motor were located outside of the exposure room so as to reduce noise

Flammability properties and radiant fraction of FRT wood plastic composites using mass loss calorimeter under HRR hood

Treesearch

Mark A. Dietenberger; Charles R. Boardman; Nicole Stark

2017-01-01

A special test arrangement was used to assess the flammability of 4 different wood plastic composites (WPC), most with fire retardants, all of which has a tendency to high smoke production leading to high radiant energy losses to the apparatus walls. The mass loss calorimeter (MLC) was modified to include a thermopile on the exhaust pipe stack to compensate for radiant...

The MASCOT Radiometer MARA for the Hayabusa 2 Mission

NASA Astrophysics Data System (ADS)

Grott, M.; Knollenberg, J.; Borgs, B.; Hänschke, F.; Kessler, E.; Helbert, J.; Maturilli, A.; Müller, N.

2017-07-01

The MASCOT radiometer MARA is a multi-spectral instrument which measures net radiative flux in six wavelength bands. MARA uses thermopile sensors as sensing elements, and the net flux between the instrument and the surface in the 18° field of view is determined by evaluating the thermoelectric potential between the sensors' absorbing surface and the thermopile's cold-junction. MARA houses 4 bandpass channels in the spectral range of 5.5-7, 8-9.5, 9.5-11.5, and 13.5-15.5 μm, as well as one long-pass channel, which is sensitive in the >3 μm range. In addition, one channel is similar to that used by the Hayabusa 2 orbiter thermal mapper, which uses a wavelength range of 8-12 μm. The primary science objective of the MARA instrument it the determination of the target asteroid's surface brightness temperature, from which surface thermal inertia can be derived. In addition, the spectral bandpass channels will be used to estimate the spectral slope of the surface in the thermal infrared wavelength range. The instrument has been calibrated using a cavity blackbody, and the temperature uncertainty is 1 K in the long pass channel for target temperatures of >173 K. Measurement uncertainty in the spectral bandpasses is 1 K for target temperatures above 273 K.

Thermoelectric ELISA for quantification of 8OHdG in a microfluidic device

NASA Astrophysics Data System (ADS)

Nestorova, Gergana

This research demonstrates the feasibility of a novel method for performing thermoelectric enzyme-linked immunosorbent assay (ELISA) in a microfluidic device. The feasibility of the thermoelectric ELISA is demonstrated by measuring the concentration of 8-hydroxy 2-deoxyguanosine (8OHdG) in urine samples from amyloid precursor protein (APP) transgenic mice. The detection method is based on formation of a complex between 8OHdG and anti-8OHdG capture antibody conjugated to biotin. The complex is immobilized over the measuring junctions of a thermopile via biotin streptavidin interaction. The concentration of the analyte is determined by using enzyme linked secondary IgG antibody specific to the primary one. The concentration of 8OHdG is determined by the initiation of an enzymatic reaction between glucose and glucose oxidase that is conjugated to the secondary IgG antibody. The heat released by the reaction of glucose and glucose oxidase is measured using an antimony-bismuth thermopile integrated in a microfluidic device. The amount of heat detected by the sensor is inversely proportional to the concentration of 8OHdG. A standard calibration curve using known concentrations of synthetic 8OHdG is generated and used to determine the concentration of the oxidized guanine in mouse urine samples.

The Shock and Vibration Bulletin. Part 3. Structural Dynamics, Machinery Dynamics and Vibration Problems

DTIC Science & Technology

1984-06-01

and to thermopile, but with a dynamically non similar control . Response limiting was accomplished by electric heat source. The test transient measuring...pulse Improvements = Final eport, Space teats were found to be reasonably simple to and Communications Group , Hughes implement and control . The time...coolant flow components, experimental studies are generally from the core is constricted by the presence r of the control rod drive line (CRDL

Wide Dynamic Range Multiband Infrared Radiometer for In-Fire Measurements of Wildland Fire Radiant Flux Density

NASA Astrophysics Data System (ADS)

Kremens, R.; Dickinson, M. B.; Hardy, C.; Skowronski, N.; Ellicott, E. A.; Schroeder, W.

2016-12-01

We have developed a wide dynamic range (24-bit) data acquisition system for collection of radiant flux density (FRFD) data from wildland fires. The data collection subsystem was designed as an Arduino `shield' and incorporates a 24-bit analog-to-digital converter, precision voltage reference, real time clock, microSD card interface, audible annuciator and interface for various digital communication interfaces (RS232, I2C, SPI, etc.). The complete radiometer system consists of our custom-designed `shield', a commercially available Arduino MEGA computer circuit board and a thermopile sensor -amplifier daughter board. Software design and development is greatly assisted by the availability of a library of public-domain, user-implemented software. The daughter board houses a 5-band radiometer using thermopiles designed for this experiment (Dexter Research Corp., Dexter, MI) to allow determination of the total FRFD from the fire (using a wide band thermopile with a KRS-5 window, 0.1 - 30 um), the FRFD as would be received by an orbital asset like MODIS (3.95 um center wavelength (CWL) and 10.95 CWL, corresponding to MODIS bands 21/22 and 31, respectively) and wider bandpass (0.1-5.5 um and 8-14 um) corresponding to the FRFD recorded by `MWIR' and `LWIR' imaging systems. We required a very wide dynamic range system in order to be able to record the flux density from `cold' ground before the fire, through the `hot' flaming combustion stage, to the `cool' phase after passage of the fire front. The recording dynamic range required (with reasonable resolution at the lowest temperatures) is on the order of 106, which is not currently available in commercial instrumentation at a price point, size or feature set that is suitable for wildland fire investigations. The entire unit, along with rechargeable battery power supply is housed in a fireproof aluminum chassis box, which is then mounted on a mast at a height of 5 - 7 m above the fireground floor. We will report initial results on observation of wildland fires using this system for prescribed fires in the pitch-pine scrub oak forest type and the use of the system to determine the differences between actual and remotely sensed measures of FRFD, which is of importance in quantifying the release of CO2 and other fire products from wildland fire combustion.

Comparison of Pyranometers and Reference Cells on Fixed and One-axis Tracking Surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooraghi, Michael R; Sengupta, Manajit; Vignola, Frank

Photovoltaic (PV) system perfomance is monitored by a wide variety of sensors. These instruments range from secondary standard pyranometers to photodiode-based pyranometers to reference cells. Although instruments are mounted in the plane of array of the modules a wide range of results have been obtained. Some of these difference have been assumed to come from systematic uncertainties associated with the irradiance sensors. This study is an attempt to quantify these differences by comparing the output of selected thermopile-based pyranometers to photodiode-based pyranometers and reference cells on a horizontal surface, a fixed-tilt surface, and a one-axis tracking surface. This analysis focusesmore » on clear-sky results from two sites with different climatic conditions. Several important features were observed. Photodiode-based pyranometers and reference cells produce widely different results under clear skies, especially at larger angles-of-incidence even though both instruments are based on measuring the short circuit current of solar cells. The difference is caused by the scattering of light as it passes through the glazing of the reference cell or the diffuser lens of the photodioded- base pyranometer. Both instruments are shown to have similar response to the spectral distribution of the irradiance when compared to the thermopile-based pyranometer that has a response nearly independent of the wavelength of light used by PV modules.« less

Characterization of Robotic Tail Orientation as a Function of Platform Position for Surf-Zone Robots

DTIC Science & Technology

2009-06-01

components. The basic components for Robster’s power supply and distribution system were taken from the Bigfoot robot developed by John Herkamp [5...18MAR2009 Changes: Eliminated all references to Bigfoot Arm and Thermopile Commented out sonar II. AGBOT Code v2.1 - 20MAR2009 Changes: Added...anaOutVolts(rt_ch, PW_STOP); anaOutVolts(lt_ch, PW_STOP); //Stops Bigfoot for (i = 0; i < 10; i++) 69

A Novel, High Energy-Density Electrical Storage Device for Electric Weapons

DTIC Science & Technology

1992-08-25

the Navy’s Earth -to-Orbit coilgun, we used to be ever so careful in assembling thermopile rings on the projectile so that the current produced by the...chosen, placed across the two conductors, to tune in steps between 50 Hz and 50 MHz. possibly operating efficiently in the GHz range. 201 DISTRIBUTION...frequencies depending on the value of capacitor chosen, placed across the two conductors, to tune in steps between 50 Hz and 50 MHz, possibly

Fabrication of thin film heat flux sensors

NASA Technical Reports Server (NTRS)

Will, Herbert

1991-01-01

Thin-film heat-flux sensors have been constructed in the form of arrays of thermocouples on upper and lower surfaces of an insulating layer, so that flux values are proportional to the temperature difference across the upper and lower surface of the insulation material. The sensor thermocouples are connected in thermopile arrangement, and the structure is patterned with photolithographic techniques. Both chromel-alumel and Pt-Pt/Rh thermocouples have been devised; the later produced 28 microvolts when exposed to the radiation of a 1000 C furnace.

Calorimetry Minisensor for the Localised Measurement of Surface Heat Dissipated from the Human Body.

PubMed

Socorro, Fabiola; Rodríguez de Rivera, Pedro Jesús; Rodríguez de Rivera, Manuel

2016-11-06

We have developed a calorimetry sensor that can perform a local measurement of the surface heat dissipated from the human body. The operating principle is based on the law of conductive heat transfer: heat dissipated by the human body passes across a thermopile located between the individual and a thermostat. Body heat power is calculated from the signals measured by the thermopile and the amount of power dissipated across the thermostat in order to maintain a constant temperature. The first prototype we built had a detection area measuring 6 × 6 cm², while the second prototype, which is described herein, had a 2 × 2 cm² detection area. This new design offers three advantages over the initial one: (1) greater resolution and three times greater thermal sensitivity; (2) a twice as fast response; and (3) it can take measurements from smaller areas of the body. The sensor has a 5 mW resolution, but the uncertainty is greater, up to 15 mW, due to the measurement and calculation procedure. The order of magnitude of measurements made in healthy subjects ranged from 60 to 300 mW at a thermostat temperature of 28 °C and an ambient room temperature of 21 °C. The values measured by the sensor depend on the ambient temperature and the thermostat's temperature, while the power dissipated depends on the individual's metabolism and any physical and/or emotional activity.

Calorimetry Minisensor for the Localised Measurement of Surface Heat Dissipated from the Human Body

PubMed Central

Socorro, Fabiola; Rodríguez de Rivera, Pedro Jesús; Rodríguez de Rivera, Manuel

2016-01-01

We have developed a calorimetry sensor that can perform a local measurement of the surface heat dissipated from the human body. The operating principle is based on the law of conductive heat transfer: heat dissipated by the human body passes across a thermopile located between the individual and a thermostat. Body heat power is calculated from the signals measured by the thermopile and the amount of power dissipated across the thermostat in order to maintain a constant temperature. The first prototype we built had a detection area measuring 6 × 6 cm2, while the second prototype, which is described herein, had a 2 × 2 cm2 detection area. This new design offers three advantages over the initial one: (1) greater resolution and three times greater thermal sensitivity; (2) a twice as fast response; and (3) it can take measurements from smaller areas of the body. The sensor has a 5 mW resolution, but the uncertainty is greater, up to 15 mW, due to the measurement and calculation procedure. The order of magnitude of measurements made in healthy subjects ranged from 60 to 300 mW at a thermostat temperature of 28 °C and an ambient room temperature of 21 °C. The values measured by the sensor depend on the ambient temperature and the thermostat’s temperature, while the power dissipated depends on the individual’s metabolism and any physical and/or emotional activity. PMID:27827977

Isothermal titration calorimetry in nanoliter droplets with subsecond time constants.

PubMed

Lubbers, Brad; Baudenbacher, Franz

2011-10-15

We reduced the reaction volume in microfabricated suspended-membrane titration calorimeters to nanoliter droplets and improved the sensitivities to below a nanowatt with time constants of around 100 ms. The device performance was characterized using exothermic acid-base neutralizations and a detailed numerical model. The finite element based numerical model allowed us to determine the sensitivities within 1% and the temporal dynamics of the temperature rise in neutralization reactions as a function of droplet size. The model was used to determine the optimum calorimeter design (membrane size and thickness, junction area, and thermopile thickness) and sensitivities for sample volumes of 1 nL for silicon nitride and polymer membranes. We obtained a maximum sensitivity of 153 pW/(Hz)(1/2) for a 1 μm SiN membrane and 79 pW/(Hz)(1/2) for a 1 μm polymer membrane. The time constant of the calorimeter system was determined experimentally using a pulsed laser to increase the temperature of nanoliter sample volumes. For a 2.5 nanoliter sample volume, we experimentally determined a noise equivalent power of 500 pW/(Hz)(1/2) and a 1/e time constant of 110 ms for a modified commercially available infrared sensor with a thin-film thermopile. Furthermore, we demonstrated detection of 1.4 nJ reaction energies from injection of 25 pL of 1 mM HCl into a 2.5 nL droplet of 1 mM NaOH. © 2011 American Chemical Society

Comparison of Pyranometers and Reference Cells on Fixed and One-Axis Tracking Surfaces: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooraghi, Michael R; Sengupta, Manajit; Vignola, Frank

A wide variety of sensors are used to monitor the irradiance incident on solar modules to evaluate the performance of photovoltaic (PV) systems. These instruments range from secondary standard pyranometers to photodiode-based pyranometers to reference cells. Although instruments are mounted in the plane of array of the modules, a wide range of results have been obtained. Some of these difference have been assumed to come from systematic uncertainties associated with the irradiance sensors. This study is an attempt to quantify these differences by comparing the output of selected thermopile pyranometers to photodiode-based pyranometers and reference cells on a horizontal surface,more » a fixed-tilt surface, and a one-axis tracking surface. This analysis focuses on clear-sky results from two sites with different climatic conditions. Several important features were observed. Photodiode-based pyranometers and reference cells produce widely different results under clear skies, especially at larger angles of incidence, even though both instruments are based on measuring the short-circuit current of solar cells. The difference is caused by the scattering of light as it passes through the glazing of the reference cell or the diffuser lens of the photodioded-base pyranometer. Both instruments are shown to have similar response to the spectral distribution of the irradiance when compared to the thermopile-based pyranometer, which has a response nearly independent of the wavelength of light used by PV modules.« less

Anomalous Nernst effect in a microfabricated thermoelectric element made of chiral antiferromagnet Mn3Sn

NASA Astrophysics Data System (ADS)

Narita, Hideki; Ikhlas, Muhammad; Kimata, Motoi; Nugroho, Agustinus Agung; Nakatsuji, Satoru; Otani, YoshiChika

2017-11-01

Toward realizing a thermopile made of the chiral anti-ferromagnet Mn3Sn, focused ion beam (FIB) lithography was employed to microfabricate a thermoelectric element consisting of a Ta/Al2O3/Mn3Sn layered structure. In this device, the Ta layer acts as a heater producing Joule heat diffusing across the Al2O3 insulating layer into the thin Mn3Sn layer. The measured Nernst signal exhibits a clear hysteresis in an applied temperature gradient and magnetic field at 300 K, and its magnitude is proportional to the square of the electrical current applied to the Ta heater. The spontaneous, zero field voltage signal in the device is of the order of a few μV, which is almost the same order of magnitude as observed in the bulk single-crystal Mn3Sn under a temperature gradient. The anomalous Nernst coefficient SANE of the microfabricated element was determined using a temperature gradient simulated by finite-element modeling. The obtained value of SANE is 0.27 μV/K, which is in good agreement with that of the reported experimental value of SANE (0.3 μV/K) for bulk single-crystal Mn3Sn. This result indicates that FIB microfabrication does not significantly alter the thermoelectric properties of bulk Mn3Sn. As the chiral antiferromagnet produces almost no stray field, our study opens the avenue for the fabrication of an efficient thermopile by densely packing the microfabricated antiferromagnetic elements.

USE OF PELTIER COOLERS AS SOIL HEAT FLUX TRANSDUCERS.

USGS Publications Warehouse

Weaver, H.L.; Campbell, G.S.

1985-01-01

Peltier coolers were modified and calibrated to serve as soil heat flux transducers. The modification was to fill their interiors with epoxy. The average calibration constant on 21 units was 13. 6 plus or minus 0. 8 kW m** minus **2 V** minus **1 at 20 degree C. This sensitivity is about eight times that of the two thermopile transducers with which comparisons were made. The thermal conductivity of the Peltier cooler transducers was 0. 4 W m** minus **1 degree C** minus **1, which is comparable to that of dry soil.

Earth radiation budget measurement from a spinning satellite: Conceptual design of detectors

NASA Technical Reports Server (NTRS)

Sromovsky, L. A.; Revercomb, H. E.; Suomi, V. E.

1975-01-01

The conceptual design, sensor characteristics, sensor performance and accuracy, and spacecraft and orbital requirements for a spinning wide-field-of-view earth energy budget detector were investigated. The scientific requirements for measurement of the earth's radiative energy budget are presented. Other topics discussed include the observing system concept, solar constant radiometer design, plane flux wide FOV sensor design, fast active cavity theory, fast active cavity design and error analysis, thermopile detectors as an alternative, pre-flight and in-flight calibration plane, system error summary, and interface requirements.

Update on the Fabrication and Performance of 2-D Arrays of Superconducting Magnesium Diboride (MgB2) Thermal Detectors for Outer-Planets Exploration

NASA Technical Reports Server (NTRS)

Lakew, Brook; Aslam, S.

2011-01-01

Detectors with better performance than the current thermopile detectors that operate at room temperature will be needed at the focal plane of far-infrared instruments on future planetary exploration missions. We will present an update on recent results from the 2-D array of MgB2 thermal detectors being currently developed at NASA Goddard. Noise and sensitivity results will be presented and compared to thermal detectors currently in use on planetary missions.

New gene cluster from the thermophile Bacillus fordii MH602 in the conversion of DL-5-substituted hydantoins to L-amino acids.

PubMed

Mei, Yan-Zhen; Wan, Yong-Min; He, Bing-Fang; Ying, Han-Jie; Ouyang, Ping-Kai

2009-12-01

The thermophile Bacillus fordii MH602 was screened for stereospecifically hydrolyzing DL-5-substituted hydantoins to L-alpha-amino acids. Since the reaction at higher temperature, the advantageous for enhancement of substrate solubility and for racemization of DL-5-substituted hydantoins during the conversion were achieved. The hydantoin metabolism gene cluster from thermophile was firstly reported in this paper. The genes involved in hydantoin utilization (hyu) were isolated on an 8.2 kb DNA fragment by Restriction Site-dependent PCR, and six ORFs were identified by DNA sequence analysis. The hyu gene cluster contained four genes with novel cluster organization characteristics: the hydantoinase gene hyuH, putative transport protein hyuP, hyperprotein hyuHP, and L-carbamoylase gene hyuC. The hyuH and hyuC genes were heterogeneously expressed in E. coli. The results indicated that hyuH and hyuC are involved in the conversion of DL-5-substituted hydantoins to an N-carbamyl intermediate that is subsequently converted to L-alpha-amino acids. Hydantoinase and carbamoylase from B. fordii MH602 comparing respectively with reported hydantoinase and carbamoylase showed the highest identities of 71% and 39%. The novel cluster organization characteristics and the difference of the key enzymes between thermopile B. fordii MH602 and other mesophiles were presumed to be related to the evolutionary origins of concerned metabolism.

Thermal Radiometer Signal Processing Using Radiation Hard CMOS Application Specific Integrated Circuits for Use in Harsh Planetary Environments

NASA Technical Reports Server (NTRS)

Quilligan, G.; DuMonthier, J.; Aslam, S.; Lakew, B.; Kleyner, I.; Katz, R.

2015-01-01

Thermal radiometers such as proposed for the Europa Clipper flyby mission require low noise signal processing for thermal imaging with immunity to Total Ionizing Dose (TID) and Single Event Latchup (SEL). Described is a second generation Multi- Channel Digitizer (MCD2G) Application Specific Integrated Circuit (ASIC) that accurately digitizes up to 40 thermopile pixels with greater than 50 Mrad (Si) immunity TID and 174 MeV-sq cm/mg SEL. The MCD2G ASIC uses Radiation Hardened By Design (RHBD) techniques with a 180 nm CMOS process node.

Shortwave Radiation

NASA Technical Reports Server (NTRS)

Klassen, Steve; Bugbee, Bruce

2005-01-01

Accurate shortwave radiation data is critical to evapotranspiration (ET) models used for developing irrigation schedules to optimize crop production while saving water, minimizing fertilizer, herbicide, and pesticide applications, reducing soil erosion, and protecting surface and ground water quality. Low cost silicon cell pyranometers have proven to be sufficiently accurate and robust for widespread use in agricultural applications under unobstructed daylight conditions. More expensive thermopile pyranometers are required for use as calibration standards and measurements under light with unique spectral properties (electric lights, under vegetation, in greenhouses and growth chambers). Routine cleaning, leveling, and annual calibration checks will help to ensure the integrity of long-term data.

Thermal Radiometer Signal Processing using Radiation Hard CMOS Application Specific Integrated Circuits for use in Harsh Planetary Environments

NASA Astrophysics Data System (ADS)

Quilligan, G.; DuMonthier, J.; Aslam, S.; Lakew, B.; Kleyner, I.; Katz, R.

2015-10-01

Thermal radiometers such as proposed for the Europa Clipper flyby mission [1] require low noise signal processing for thermal imaging with immunity to Total Ionizing Dose (TID) and Single Event Latchup (SEL). Described is a second generation Multi- Channel Digitizer (MCD2G) Application Specific Integrated Circuit (ASIC) that accurately digitizes up to 40 thermopile pixels with greater than 50 Mrad (Si) immunity TID and 174 MeV-cm2/mg SEL. The MCD2G ASIC uses Radiation Hardened By Design (RHBD) techniques with a 180 nm CMOS process node.

Probe Measures Fouling As In Heat Exchangers

NASA Technical Reports Server (NTRS)

Marner, Wilbur J.; Macdavid, Kenton S.

1990-01-01

Combustion deposits reduce transfer of heat. Instrument measures fouling like that on gas side of heat exchanger in direct-fired boiler or heat-recovery system. Heat-flux probe includes tube with embedded meter in outer shell. Combustion gases flow over probe, and fouling accumulates on it, just as fouling would on heat exchanger. Embedded heat-flow meter is sandwich structure in which thin Chromel layers and middle alloy form thermopile. Users determine when fouling approaches unacceptable levels so they schedule cleaning and avoid decreased transfer of heat and increased drop in pressure fouling causes. Avoids cost of premature, unnecessary maintenance.

Effect of temperature on methanogenesis stage of two-stage anaerobic digestion of palm oil mill effluent (POME) into biogas

NASA Astrophysics Data System (ADS)

Trisakti, B.; Irvan, Mahdalena; Taslim; Turmuzi, M.

2017-06-01

This study aimed to determine the effect of temperature on methanogenesis stage of conversion of palm oil mill effluent into biogas. Methanogenesis is the second stage of methanogenic anaerobic digestion. Improved performance of the methanogenesis process was determined by measuring the growth of microorganisms, degradation of organic materials, biogas production and composition. Initially, the suitable loading up was determined by varying the HRT 100, 40, 6, and 4.0 days in the continuous stirred tank reactor (CSTR) with mixing rate 100 rpm, pH 6.7-7.5 at room temperature. Next, effect of temperature on the process was determined by varying temperature at mesophilic range (30-42°C) and thermophilic range (43-55°C). Analysis of total solids (TS), volatile solids (VS), total suspended solids (TSS), volatile suspended solids (VSS), and chemical oxygen demand (COD) were conducted in order to study the growth of microorganisms and their abilities in converting organic compound to produce biogas. Degradation of organic content i.e. VS decomposition and COD removal increased with the increasing of temperature. At mesophilic range, VS decomposition and COD removal were 51.56 ± 8.30 and 79.82 ± 6.03, respectively. Meanwhile at thermopilic range, VS decomposition and COD removal were 67.44 ± 3.59 and 79.16 ± 1.75, respectively. Biogas production and its methane content also increased with the increasing of temperature, but CO2 content also increased. Biogas production at mesophilic range was 31.77 ± 3.46 L/kg-ΔVS and methane content was 75 . Meanwhile, biogas production at thermopilic range was 37.03 ± 5.16 L/kg-ΔVS and methane content was 62.25 ± 5.50 .

Rugged, Low Cost, Environmental Sensors for a Turbulent World

NASA Astrophysics Data System (ADS)

Schulz, B.; Sandell, C. T.; Wickert, A. D.

2017-12-01

Ongoing scientific research and resource management require a diverse range of high-quality and low-cost sensors to maximize the number and type of measurements that can be obtained. To accomplish this, we have developed a series of diversified sensors for common environmental applications. The TP-DownHole is an ultra-compact temperature and pressure sensor designed for use in CMT (Continuous Multi-channel Tubing) multi-level wells. Its 1 mm water depth resolution, 30 cm altitude resolution, and rugged design make it ideal for both water level measurements and monitoring barometric pressure and associated temperature changes. The TP-DownHole sensor has also been incorporated into a self-contained, fully independent data recorder for extreme and remote environments. This device (the TP-Solo) is based around the TP-DownHole design, but has self-contained power and data storage and is designed to collect data independently for up to 6 months (logging at once an hour), creating a specialized tool for extreme environment data collection. To gather spectral information, we have also developed a very low cost photodiode-based Lux sensor to measure spectral irradiance; while this does not measure the entire solar radiation spectrum, simple modeling to rescale the remainder of the solar spectrum makes this a cost-effective alternative to a thermopile pyranometer. Lastly, we have developed an instrumentation amplifier which is designed to interface a wide range of sensitive instruments to common data logging systems, such as thermopile pyranometers, thermocouples, and many other analog output sensors. These three instruments are the first in a diverse family aimed to give researchers a set of powerful and low-cost tools for environmental instrumentation.

Going Places No Infrared Temperature Devices Have Gone Before

NASA Technical Reports Server (NTRS)

2003-01-01

Exergen's IRt/c is a self-powered sensor that matches a thermocouple within specified temperature ranges and provides a predictable and repeatable signal outside of this specified range. Possessing an extremely fast time constant, the infrared technology allows users to measure product temperature without touching the product. The IRt/c uses a device called a thermopile to measure temperature and generate current. Traditionally, these devices are not available in a size that would be compatible with the Exergen IRt/c, based on NASA s quarterinch specifications. After going through five circuit designs to find a thermopile that would suit the IRt/c design and match the signal needed for output, Exergen maintains that it developed a model that totaled just 20 percent of the volume of the previous smallest detector in the world. Following completion of the project with Glenn, Exergen continued development of the IRt/c for other customers, spinning off a new product line called the micro IRt/c. This latest development has broadened applications for industries that previously could not use infrared thermometers due to size constraints. The first commercial use of the micro IRt/c involved an original equipment manufacturer that makes laminating machinery consisting of heated rollers in very tight spots. Accurate temperature measurement for this application requires close proximity to the heated rollers. With the micro IRt/c s 50-millisecond time constant, the manufacturer is able to gain closer access to the intended temperature targets for exact readings, thereby increasing productivity and staying ahead of competition.In a separate application, the infrared temperature sensor is being utilized for avalanche warnings in Switzerland. The IRt/c is mounted about 5 meters above the ground to measure the snow cover throughout the mountainous regions of the country.

Characterization of nanometer-thick polycrystalline silicon with phonon-boundary scattering enhanced thermoelectric properties and its application in infrared sensors.

PubMed

Zhou, Huchuan; Kropelnicki, Piotr; Lee, Chengkuo

2015-01-14

Although significantly reducing the thermal conductivity of silicon nanowires has been reported, it remains a challenge to integrate silicon nanowires with structure materials and electrodes in the complementary metal-oxide-semiconductor (CMOS) process. In this paper, we investigated the thermal conductivity of nanometer-thick polycrystalline silicon (poly-Si) theoretically and experimentally. By leveraging the phonon-boundary scattering, the thermal conductivity of 52 nm thick poly-Si was measured as low as around 12 W mK(-1) which is only about 10% of the value of bulk single crystalline silicon. The ZT of n-doped and p-doped 52 nm thick poly-Si was measured as 0.067 and 0.024, respectively, while most previously reported data had values of about 0.02 and 0.01 for a poly-Si layer with a thickness of 0.5 μm and above. Thermopile infrared sensors comprising 128 pairs of thermocouples made of either n-doped or p-doped nanometer-thick poly-Si strips in a series connected by an aluminium (Al) metal interconnect layer are fabricated using microelectromechanical system (MEMS) technology. The measured vacuum specific detectivity (D*) of the n-doped and p-doped thermopile infrared (IR) sensors are 3.00 × 10(8) and 1.83 × 10(8) cm Hz(1/2) W(-1) for sensors of 52 nm thick poly-Si, and 5.75 × 10(7) and 3.95 × 10(7) cm Hz(1/2) W(-1) for sensors of 300 nm thick poly-Si, respectively. The outstanding thermoelectric properties indicate our approach is promising for diverse applications using ultrathin poly-Si technology.

Solar variability and climate change: An historical perspective

NASA Astrophysics Data System (ADS)

Feldman, Theodore S.

There is nothing new about the debate over the Sun's influence on terrestrial climate.As early as the late 18th century, widespread concern for the deterioration of the Earth's climate led to speculation about the Sun's role in climate change [Feldman, 1993; Fleming, 1990]. Drawing analogies with variations in the brightness of stars, the British astronomer William Herschel suggested that greater sunspot activity would result in warmer terrestrial climates. Herschel supported his hypothesis by referring to price series for wheat published in Adam Smiths Wealth of Nations [Hufbauer, 1991]. Later, the eminent American physicist Joseph Henry demonstrated by thermopile measurements that, contrary to Herschel's assumption, sunspots were cooler than the unblemished portions of the solar disk.

Micron-Scale Differential Scanning Calorimeter on a Chip

DOEpatents

Cavicchi, Richard E; Poirier, Gregory Ernest; Suehle, John S; Gaitan, Michael; Tea, Nim H

1998-06-30

A differential scanning microcalorimeter produced on a silicon chip enables microscopic scanning calorimetry measurements of small samples and thin films. The chip may be fabricated using standard CMOS processes. The microcalorimeter includes a reference zone and a sample zone. The reference and sample zones may be at opposite ends of a suspended platform or may reside on separate platforms. An integrated polysilicon heater provides heat to each zone. A thermopile consisting of a succession of thermocouple junctions generates a voltage representing the temperature difference between the reference and sample zones. Temperature differences between the zones provide information about the chemical reactions and phase transitions that occur in a sample placed in the sample zone.

Micromachined nanocalorimetric sensor for ultra-low-volume cell-based assays.

PubMed

Johannessen, Erik A; Weaver, John M R; Bourova, Lenka; Svoboda, Petr; Cobbold, Peter H; Cooper, Jonathan M

2002-05-01

Current strategies for cell-based screening generally focus on the development of highly specific assays, which require an understanding of the nature of the signaling molecules and cellular pathways involved. In contrast, changes in temperature of cells provides a measure of altered cellular metabolism that is not stimulus specific and hence could have widespread applications in cell-based screening of receptor agonists and antagonists, as well as in the assessment of toxicity of new lead compounds. Consequently, we have developed a micromachined nanocalorimetric biological sensor using a small number of isolated living cells integrated within a subnanoliter format, which is capable of detecting 13 nW of generated power from the cells, upon exposure to a chemical or pharmaceutical stimulus. The sensor comprises a 10-junction gold and nickel thermopile, integrated on a silicon chip which was back-etched to span a 800-nm-thick membrane of silicon nitride. The thin-film membrane, which supported the sensing junctions of the thermoelectric transducer, gave the system a temperature resolution of 0.125 mK, a low heat capacity of 1.2 nJ mK(-1), and a rapid (unfiltered) response time of 12 ms. The application of the system in ultra-low-volume cell-based assays could provide a rapid endogenous screen. It offers important additional advantages over existing methods in that it is generic in nature, it does not require the use of recombinant cell lines or of detailed assay development, and finally, it can enable the use of primary cell lines or tissue biopsies.

A 0.18 micrometer CMOS Thermopile Readout ASIC Immune to 50 MRAD Total Ionizing Dose (SI) and Single Event Latchup to 174MeV-cm(exp 2)/mg

NASA Technical Reports Server (NTRS)

Quilligan, Gerard T.; Aslam, Shahid; Lakew, Brook; DuMonthier, Jeffery J.; Katz, Richard B.; Kleyner, Igor

2014-01-01

Radiation hardened by design (RHBD) techniques allow commercial CMOS circuits to operate in high total ionizing dose and particle fluence environments. Our radiation hard multi-channel digitizer (MCD) ASIC (Figure 1) is a versatile analog system on a chip (SoC) fabricated in 180nm CMOS. It provides 18 chopper stabilized amplifier channels, a 16- bit sigma-delta analog-digital converter (SDADC) and an on-chip controller. The MCD was evaluated at Goddard Space Flight Center and Texas A&M University's radiation effects facilities and found to be immune to single event latchup (SEL) and total ionizing dose (TID) at 174 MeV-cm(exp 2)/mg and 50 Mrad (Si) respectively.

A Compact, Multi-view Net Flux Radiometer for Future Uranus and Neptune Probes

NASA Technical Reports Server (NTRS)

Aslam, S.; Amato, M.; Atkinson, D. H.; Hewagama, T.; Jennings, D. E.; Nixon, C. A.; Mousis, O.

2017-01-01

A Net Flux Radiometer (NFR) is presented that can be included in an atmospheric structure instrument suite for future probe missions to the icy giants Uranus and Neptune. The baseline design has two spectral channels i.e., a solar channel (0.4-to-3.5 m) and a thermal channel (4-to-300 m). The NFR is capable of viewing five distinct viewing angles during the descent. Non-imaging Winston cones with band-pass filters are used for each spectral channel and to define a 5 angular acceptance. Uncooled thermopile detectors are used in each spectral channel and are read out using a custom radiation hard application specific integrated circuit (ASIC). The baseline design can easily be changed to increase the number of detector channels from two to seven.

A batch process micromachined thermoelectric energy harvester: fabrication and characterization

NASA Astrophysics Data System (ADS)

Su, J.; Leonov, V.; Goedbloed, M.; van Andel, Y.; de Nooijer, M. C.; Elfrink, R.; Wang, Z.; Vullers, R. J. M.

2010-10-01

Micromachined thermopiles are considered as a cost-effective solution for energy harvesters working at a small temperature difference and weak heat flows typical for, e.g., the human body. They can be used for powering autonomous wireless sensor nodes in a body area network. In this paper, a micromachined thermoelectric energy harvester with 6 µm high polycrystalline silicon germanium (poly-SiGe) thermocouples fabricated on a 6 inch wafer is presented. An open circuit voltage of 1.49 V and an output power of 0.4 µW can be generated with 3.5 K temperature difference in a model of a wearable micromachined energy harvester of the discussed design, which has a die size of 1.0 mm × 2.5 mm inside a watch-size generator.

NASA Tech Briefs, May 2003

NASA Technical Reports Server (NTRS)

2003-01-01

Topics covered include: Using Diffusion Bonding in Making Piezoelectric Actuators; Wireless Temperature-Monitoring System; Analog Binaural Circuits for Detecting and Locating Leaks; Mirrors Containing Biomimetic Shape-Control Actuators; Surface-Micromachined Planar Arrays of Thermopiles; Cascade Back-Propagation Learning in Neural Networks; Perovskite Superlattices as Tunable Microwave Devices; Rollable Thin-Shell Nanolaminate Mirrors; Flight Tests of a Ministick Controller in an F/A-18 Airplane; Piezoelectrically Actuated Shutter for High Vacuum; Bio-Inspired Engineering of Exploration Systems; Microscope Cells Containing Multiple Micromachined Wells; Electrophoretic Deposition for Fabricating Microbatteries; Integrated Arrays of Ion-Sensitive Electrodes; Model of Fluidized Bed Containing Reacting Solids and Gases; Membrane Mirrors With Bimorph Shape Actuators; Using Fractional Clock-Period Delays in Telemetry Arraying; Developing Generic Software for Spacecraft Avionics; Numerical Study of Pyrolysis of Biomass in Fluidized Beds; and Assessment of Models of Chemically Reacting Granular Flows.

Vibration welding system with thin film sensor

DOEpatents

Cai, Wayne W; Abell, Jeffrey A; Li, Xiaochun; Choi, Hongseok; Zhao, Jingzhou

2014-03-18

A vibration welding system includes an anvil, a welding horn, a thin film sensor, and a process controller. The anvil and horn include working surfaces that contact a work piece during the welding process. The sensor measures a control value at the working surface. The measured control value is transmitted to the controller, which controls the system in part using the measured control value. The thin film sensor may include a plurality of thermopiles and thermocouples which collectively measure temperature and heat flux at the working surface. A method includes providing a welder device with a slot adjacent to a working surface of the welder device, inserting the thin film sensor into the slot, and using the sensor to measure a control value at the working surface. A process controller then controls the vibration welding system in part using the measured control value.

Traceable terahertz power measurement from 1 THz to 5 THz.

PubMed

Steiger, Andreas; Kehrt, Mathias; Monte, Christian; Müller, Ralf

2013-06-17

The metrology institute in Germany, the Physikalisch-Technische Bundesanstalt (PTB), calibrates the spectral responsivity of THz detectors at 2.52 THz traceable to International System of Units. The Terahertz detector calibration facility is equipped with a standard detector calibrated against a cryogenic radiometer at this frequency. In order to extend this service to a broader spectral range in the THz region a new standard detector was developed. This detector is based on a commercial thermopile detector. Its absorber was modified and characterized by spectroscopic methods with respect to its absorptance and reflectance from 1 THz to 5 THz and at the wavelength of a helium-neon laser in the visible spectral range. This offers the possibility of tracing back the THz power responsivity scale to the more accurate responsivity scale in the visible spectral range and thereby to reduce the uncertainty of detector calibrations in the THz range significantly.

On the Use of a Low-Cost Thermal Sensor to Improve Kinect People Detection in a Mobile Robot

PubMed Central

Susperregi, Loreto; Sierra, Basilio; Castrillón, Modesto; Lorenzo, Javier; Martínez-Otzeta, Jose María; Lazkano, Elena

2013-01-01

Detecting people is a key capability for robots that operate in populated environments. In this paper, we have adopted a hierarchical approach that combines classifiers created using supervised learning in order to identify whether a person is in the view-scope of the robot or not. Our approach makes use of vision, depth and thermal sensors mounted on top of a mobile platform. The set of sensors is set up combining the rich data source offered by a Kinect sensor, which provides vision and depth at low cost, and a thermopile array sensor. Experimental results carried out with a mobile platform in a manufacturing shop floor and in a science museum have shown that the false positive rate achieved using any single cue is drastically reduced. The performance of our algorithm improves other well-known approaches, such as C4 and histogram of oriented gradients (HOG). PMID:24172285

Computer modeling of thermoelectric generator performance

NASA Technical Reports Server (NTRS)

Chmielewski, A. B.; Shields, V.

1982-01-01

Features of the DEGRA 2 computer code for simulating the operations of a spacecraft thermoelectric generator are described. The code models the physical processes occurring during operation. Input variables include the thermoelectric couple geometry and composition, the thermoelectric materials' properties, interfaces and insulation in the thermopile, the heat source characteristics, mission trajectory, and generator electrical requirements. Time steps can be specified and sublimation of the leg and hot shoe is accounted for, as are shorts between legs. Calculations are performed for conduction, Peltier, Thomson, and Joule heating, the cold junction can be adjusted for solar radition, and the legs of the thermoelectric couple are segmented to enhance the approximation accuracy. A trial run covering 18 couple modules yielded data with 0.3% accuracy with regard to test data. The model has been successful with selenide materials, SiGe, and SiN4, with output of all critical operational variables.

Burner ignition system

DOEpatents

Carignan, Forest J.

1986-01-21

An electronic ignition system for a gas burner is battery operated. The battery voltage is applied through a DC-DC chopper to a step-up transformer to charge a capacitor which provides the ignition spark. The step-up transformer has a significant leakage reactance in order to limit current flow from the battery during initial charging of the capacitor. A tank circuit at the input of the transformer returns magnetizing current resulting from the leakage reactance to the primary in succeeding cycles. An SCR in the output circuit is gated through a voltage divider which senses current flow through a flame. Once the flame is sensed, further sparks are precluded. The same flame sensor enables a thermopile driven main valve actuating circuit. A safety valve in series with the main gas valve responds to a control pressure thermostatically applied through a diaphragm. The valve closes after a predetermined delay determined by a time delay orifice if the pilot gas is not ignited.

A Radiation Hard Multi-Channel Digitizer ASIC for Operation in the Harsh Jovian Environment

NASA Technical Reports Server (NTRS)

Aslam, Shahid; Aslam, S.; Akturk, A.; Quilligan, G.

2011-01-01

In 1995, the Galileo spacecraft arrived at Jupiter to conduct follow-up experiments on pathfinder Pioneer and key Voyager discoveries especially at Io, Europa, Ganymede and Callisto. These new observations helped expand our scientific knowledge of the prominent Galilean satellites; studies revealed diversity with respect to their geology, internal structure, evolution and degree of past and present activity. Jupiter's diverse Galilean satellites, of which three are believed to harbor internal oceans, are central to understanding the habitability of icy worlds. Galileo provided for the first time compelling evidence of a near-surface global ocean on Europa. Furthermore, by understanding the Jupiter system and unraveling the history of its evolution from initial formation to the emergence of possible habitats and life, gives insight into how giant planets and their satellite systems form and evolve. Most important, new light is shed on the potential for the emergence and existence of life in icy satellite oceans. In 2009, NASA released a detailed Jupiter Europa Mission Study (EJSM) that proposed an ambitious Flagship Mission to understand more fully the satellites Europa and Ganymede within the context of the Jovian system. Key to EJSM is the NASA led Jupiter Europa Orbiter (JEO) and the ESA led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute a choreographed exploration of the Jovian system before settling into orbit around Europa and Ganymede, respectively. The National Academies Planetary Decadal Survey, 2011 has listed the NASA-led JEO as the second highest priority mission for the decade 2013-2022, and if chosen it would be launched in 2020 with arrival at Jupiter in 2025. If the JEO mission is not chosen it is anticipated that there will be opportunities in future decadal cycles. Jupiter Orbit Insertion (JOI) begins a 30-month Jovian system tour followed by nine months of science mapping after Europa Orbit Insertion (EOI) in July 2028. The orbiter will ultimately impact the surface of Europa after the mission is completed. The current JEO mission concept includes a range of instruments on the payload, to monitor dynamic phenomena (such as Io's volcanoes and Jupiters atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede. The payload includes a low mass (3.7 Kg) and low power (< 5 W) Thermal Instrument (TI) concept for measuring possible warm thermal anomalies on Europa s cold surface caused by recent (< 10,000 years) eruptive activity. Regions of anomalously high heat flow will be identified by thermal mapping using a nadir pointing, push-broom filter radiometer that provides far-IR imagery in two broad band spectral wavelength regions, 8-20 m and 20-100 m, for surface temperature measurements with better than a 2 K accuracy and a spatial resolution of 250 m/pixel obtained from a 100 Km orbit. The temperature accuracy permits a search for elevated temperatures when combined with albedo information. The spatial resolution is sufficient to resolve Europa's larger cracks and ridge axial valleys. In order to accomplish the thermal mapping, the TI uses sensitive thermopile arrays that are readout by a custom designed low-noise Multi-Channel Digitizer (MCD) ASIC that resides very close to the thermopile linear array outputs. Both the thermopile array and the MCD ASIC will need to show full functionality within the harsh Jovian radiation environment, operating at cryogenic temperatures, typically 150 K to 170 K. In the following, a radiation mitigation strategy together with a low risk Radiation-Hardened-By-Design (RHBD) methodology using commercial foundry processes is given for the design and manufacture of a MCD ASIC that will meet this challenge.

Calorimetric determination of the heat of combustion of spent Green River shale at 978 K

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mraw, S.C.; Keweshan, C.F.

1987-08-01

A Calvet-type calorimeter was used to measure heats of combustion of spent Colorado oil shales. For Green River shale, the samples were members of a sink-float series spanning oil yields from 87 to 340 L . tonne/sup -1/. Shale samples (30-200 mg) are dropped into the calorimeter at high temperature, and a peak in the thermopile signal records the total enthalpy change of the sample between room temperature and the final temperature. Duplicate samples from the above sink-float series were first retorted at 773 K and then dropped separately into nitrogen and oxygen at 978 K. The resulting heats aremore » subtracted to give the heat of combustion, and the results are compared to values from classical bomb calorimetry. The agreement shows that the heats of combustion of the organic component are well understood but that question remain on the reactions of the mineral components.« less

Laser power meters as an X-ray power diagnostic for LCLS-II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heimann, Philip; Moeller, Stefan; Carbajo, Sergio

For the LCLS-II X-ray instruments, laser power meters are being developed as compact X-ray power diagnostics to operate at soft and tender X-ray photon energies. These diagnostics can be installed at various locations along an X-ray free-electron laser (FEL) beamline in order to monitor the transmission of X-ray optics along the beam path. In addition, the power meters will be used to determine the absolute X-ray power at the endstations. Here, thermopile power meters, which measure average power, and have been chosen primarily for their compatibility with the high repetition rates at LCLS-II, are evaluated. Here, a number of characteristicsmore » in the soft X-ray range are presented including linearity, calibrations conducted with a photodiode and a gas monitor detector as well as ultra-high-vacuum compatibility tests using residual gas analysis. The application of these power meters for LCLS-II and other X-ray FEL sources is discussed.« less

MEMS-based IR-sources

NASA Astrophysics Data System (ADS)

Weise, Sebastian; Steinbach, Bastian; Biermann, Steffen

2016-03-01

The series JSIR350 sources are MEMS based infrared emitters. These IR sources are characterized by a high radiation output. Thus, they are excellent for NDIR gas analysis and are ideally suited for using with our pyro-electric or thermopile detectors. The MEMS chips used in Micro-Hybrid's infrared emitters consist of nano-amorphous carbon (NAC). The MEMS chips are produced in the USA. All Micro-Hybrid Emitter are designed and specified to operate up to 850°C. The improvements we have made in the source's packaging enable us to provide IR sources with the best performance on the market. This new technology enables us to seal the housings of infrared radiation sources with soldered infrared filters or windows and thus cause the parts to be impenetrable to gases. Micro-Hybrid provide various ways of adapting our MEMS based infrared emitter JSIR350 to customer specifications, like specific burn-in parameters/characteristic, different industrial standard housings, producible with customized cap, reflector or pin-out.

Low cost Earth attitude sensor

NASA Astrophysics Data System (ADS)

Liberati, Fabrizio; Perrotta, Giorgio; Verzegnassi, Fulvia

2017-11-01

A patent-pending, low-cost, moderate performance, Earth Attitude Sensor for LEO satellites is described in this paper. The paper deals with the system concepts, the technology adopted and the simulation results. The sensor comprises three or four narrow field of view mini telescopes pointed towards the Earth edge to detect and measure the variation of the off-nadir angle of the Earth-to-black sky transition using thermopile detectors suitably placed in the foci of the optical min telescopes. The system's innovation consists in the opto-mechanical configuration adopted that is sturdy and has no moving parts being , thus, inherently reliable. In addition, with a view to reducing production costs, the sensor does without hi-rel and is instead mainly based on COTS parts suitably chosen. Besides it is flexible and can be adapted to perform attitude measurement onboard spacecraft flying in orbits other than LEO with a minimum of modifications to the basic design. At present the sensor is under development by IMT and OptoService.

Laser power meters as an X-ray power diagnostic for LCLS-II.

PubMed

Heimann, Philip; Moeller, Stefan; Carbajo, Sergio; Song, Sanghoon; Dakovski, Georgi; Nordlund, Dennis; Fritz, David

2018-01-01

For the LCLS-II X-ray instruments, laser power meters are being developed as compact X-ray power diagnostics to operate at soft and tender X-ray photon energies. These diagnostics can be installed at various locations along an X-ray free-electron laser (FEL) beamline in order to monitor the transmission of X-ray optics along the beam path. In addition, the power meters will be used to determine the absolute X-ray power at the endstations. Here, thermopile power meters, which measure average power, and have been chosen primarily for their compatibility with the high repetition rates at LCLS-II, are evaluated. A number of characteristics in the soft X-ray range are presented including linearity, calibrations conducted with a photodiode and a gas monitor detector as well as ultra-high-vacuum compatibility tests using residual gas analysis. The application of these power meters for LCLS-II and other X-ray FEL sources is discussed.

Laser power meters as an X-ray power diagnostic for LCLS-II

DOE PAGES

Heimann, Philip; Moeller, Stefan; Carbajo, Sergio; ...

2018-01-01

For the LCLS-II X-ray instruments, laser power meters are being developed as compact X-ray power diagnostics to operate at soft and tender X-ray photon energies. These diagnostics can be installed at various locations along an X-ray free-electron laser (FEL) beamline in order to monitor the transmission of X-ray optics along the beam path. In addition, the power meters will be used to determine the absolute X-ray power at the endstations. Here, thermopile power meters, which measure average power, and have been chosen primarily for their compatibility with the high repetition rates at LCLS-II, are evaluated. Here, a number of characteristicsmore » in the soft X-ray range are presented including linearity, calibrations conducted with a photodiode and a gas monitor detector as well as ultra-high-vacuum compatibility tests using residual gas analysis. The application of these power meters for LCLS-II and other X-ray FEL sources is discussed.« less

Fabrication of Thin Film Heat Flux Sensors

NASA Technical Reports Server (NTRS)

Will, Herbert A.

1992-01-01

Prototype thin film heat flux sensors have been constructed and tested. The sensors can be applied to propulsion system materials and components. The sensors can provide steady state and fast transient heat flux information. Fabrication of the sensor does not require any matching of the mounting surface. Heat flux is proportional to the temperature difference across the upper and lower surfaces of an insulation material. The sensor consists of an array of thermocouples on the upper and lower surfaces of a thin insulating layer. The thermocouples for the sensor are connected in a thermopile arrangement. A 100 thermocouple pair heat flux sensor has been fabricated on silicon wafers. The sensor produced an output voltage of 200-400 microvolts when exposed to a hot air heat gun. A 20 element thermocouple pair heat flux sensor has been fabricated on aluminum oxide sheet. Thermocouples are Pt-Pt/Rh with silicon dioxide as the insulating material. This sensor produced an output of 28 microvolts when exposed to the radiation of a furnace operating at 1000 C. Work is also underway to put this type of heat flux sensor on metal surfaces.

NREL Pyrheliometer Comparisons: September 26-October 7, 2016 (NPC-2016)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reda, Ibrahim; Dooraghi, Mike; Andreas, Afshin

Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for developing and deploying solar energy conversion systems, improving our understanding of the Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations that are traceable to an international standard is the first step in producing research-quality solar irradiance measurements. National Renewable Energy Laboratory (NREL) pyrheliometer comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) inmore » Golden, Colorado. Open to all pyrheliometer owners and operators, each NPC provides an opportunity to determine the unique World Radiometric Reference transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the WRR. NPC-2016 was September 26 through October 7, 2016. Participants operated 45 absolute cavity radiometers and 27 conventional thermopile-based pyrheliometers to simultaneously measure clear-sky, direct normal solar irradiance during this period.« less

In-flight Far-Infrared Performance of the CIRS Instrument on Cassini

NASA Technical Reports Server (NTRS)

Nixon, Conor A.; Brasunas, John C.; Lakew, Brook; Fettig, Rainer; Jennings, Donald E.; Carlson, Ronald; Kunde, Virgil G.

2004-01-01

The Composite Infrared Spectrometer (CIRS) on-board Cassini consists of two interferometers: a conventional Michelson for the mid-infrared; and a Martin-Puplett type in the far-infrared employing wire grid polarizers to split, recombine and analyze the radiation. The far-IR focal plane (FP1) assembly uses two thermopile detectors to measure the final transmitted and reflected beams at the polarizer-analyzer: if one fails, the interferometer can still operate, albeit with a lower efficiency. The combined effect is for good response from 10 to 300/cm, and declining response to 600/cm. This paper will examine in-flight performance of the far-IR interferometer, including NESR and response. Regular noise spikes, resulting from pickup from other electrical sub-systems has been found on the CIRS interferograms, and the removal of these effects is discussed. The radiometric calibration is described, and then we show how the calibration was applied to science data taken during the Jupiter flyby of December 2000. Finally, we discuss signal-to-noise on the calibrated spectra, emphasizing limitations of the current instrument and the potential for improvement in future missions.

The Impact of Indoor and Outdoor Radiometer Calibration on Solar Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habte, Aron; Sengupta, Manajit; Andreas, Afshin

2016-06-02

This study addresses the effect of calibration methodologies on calibration responsivities and the resulting impact on radiometric measurements. The calibration responsivities used in this study are provided by NREL's broadband outdoor radiometer calibration (BORCAL) and a few prominent manufacturers. The BORCAL method provides outdoor calibration responsivity of pyranometers and pyrheliometers at a 45 degree solar zenith angle and responsivity as a function of solar zenith angle determined by clear-sky comparisons to reference irradiance. The BORCAL method also employs a thermal offset correction to the calibration responsivity of single-black thermopile detectors used in pyranometers. Indoor calibrations of radiometers by their manufacturersmore » are performed using a stable artificial light source in a side-by-side comparison of the test radiometer under calibration to a reference radiometer of the same type. These different methods of calibration demonstrated 1percent to 2 percent differences in solar irradiance measurement. Analyzing these values will ultimately enable a reduction in radiometric measurement uncertainties and assist in developing consensus on a standard for calibration.« less

Method for determining thermal conductivity and thermal capacity per unit volume of earth in situ

DOEpatents

Poppendiek, Heinz F.

1982-01-01

A method for determining the thermal conductivity of the earth in situ is based upon a cylindrical probe (10) having a thermopile (16) for measuring the temperature gradient between sets of thermocouple junctions (18 and 20) of the probe after it has been positioned in a borehole and has reached thermal equilibrium with its surroundings, and having means (14) for heating one set of thermocouple junctions (20) of the probe at a constant rate while the temperature gradient of the probe is recorded as a rise in temperature over several hours (more than about 3 hours). A fluid annulus thermally couples the probe to the surrounding earth. The recorded temperature curves are related to the earth's thermal conductivity, k.sub..infin., and to the thermal capacity per unit volume, (.gamma.c.sub.p).sub..infin., by comparison with calculated curves using estimates of k.sub..infin. and (.gamma.c.sub.p).sub..infin. in an equation which relates these parameters to a rise in the earth's temperature for a known and constant heating rate.

Crystallographic effects during radiative melting of semitransparent materials

NASA Astrophysics Data System (ADS)

Webb, B. W.; Viskanta, R.

1987-10-01

Experiments have been performed to illustrate crystallogrpahic effects during radiative melting of unconfined vertical layers of semitransparent material. Radiative melting of a polycrystalline paraffin was performed and the instantaneous layer weight and transmittance were measured using a cantilever beam technique and thermopile radiation detector, respectively. The effects of radiative flux, initial solid subcooling, spectral distribution of the irradiation, and crystal structure of the solid as determined qualitatively by the sample solidification rate were studied. Experimental results show conclusively the dominant influence of cystallographic effects in the form of multiple internal scattering of radiation during the melting process. A theoretical model is formulated to predict the melting rate of the material. Radiation transfer is treated by solving the one-dimensional radiative transfer equation for an absorbing-scattering medium using the discrete ordinates method. Melting rate and global layer reflectance as predicted by the model agree well with experimental data. Parametric studies conducted with the model illustrate the sensitivity of the melting behavior to such variables as incident radiative flux, initial layer opacity (material extinction coefficient), and scattering asymmetry factor.

Heat-exchanger concepts for neutral-beam calorimeters

NASA Astrophysics Data System (ADS)

Thompson, C. C.; Polk, D. H.; McFarlin, D. J.; Stone, R.

1981-10-01

Advanced cooling concepts that permit the design of water cooled heat exchangers for use as calorimeters and beam dumps for advanced neutral beam injection systems were evaluated. Water cooling techniques ranging from pool boiling to high pressure, high velocity swirl flow were considered. Preliminary performance tests were carried out with copper, inconel and molybdenum tubes ranging in size from 0.19 to 0.50 in. diameter. Coolant flow configurations included: (1) smooth tube/straight flow; (2) smooth tube with swirl flow created by tangential injection of the coolant; and (3) axial flow in internally finned tubes. Additionally, the effect of tube L/D was evaluated. A CO2 laser was employed to irradiate a sector of the tube exterior wall; the laser power was incrementally increased until burnout occurred. Absorbed heat fluxes were calculated by dividing the measured coolant heat load by the area of the burn spot on the tube surface. Two six element thermopiles were used to accurately determine the coolant temperature rise. A maximum burnout heat flux near 14 kW/sq cm was obtained for the molybdenum tube swirl flow configuration.

Measurement of a surface heat flux and temperature

NASA Astrophysics Data System (ADS)

Davis, R. M.; Antoine, G. J.; Diller, T. E.; Wicks, A. L.

1994-04-01

The Heat Flux Microsensor is a new sensor which was recently patented by Virginia Tech and is just starting to be marketed by Vatell Corp. The sensor is made using the thin-film microfabrication techniques directly on the material that is to be measured. It consists of several thin-film layers forming a differential thermopile across a thermal resistance layer. The measured heat flux q is proportional to the temperature difference across the resistance layer q= k(sub g)/delta(sub g) x (t(sub 1) - T(sub 2)), where k(sub g) is the thermal conductivity and delta (sub g) is the thickness of the thermal resistance layer. Because the gages are sputter coated directly onto the surface, their total thickness is less than 2 micrometers, which is two orders of magnitude thinner than previous gages. The resulting temperature difference across the thermal resistance layer (delta is less than 1 micrometer) is very small even at high heat fluxes. To generate a measurable signal many thermocouple pairs are put in series to form a differential thermopile. The combination of series thermocouple junctions and thin-film design creates a gage with very attractive characteristics. It is not only physically non-intrusive to the flow, but also causes minimal disruption of the surface temperature. Because it is so thin, the response time is less than 20 microsec. Consequently, the frequency response is flat from 0 to over 50 kHz. Moreover, the signal of the Heat Flux Microsensor is directly proportional to the heat flux. Therefore, it can easily be used in both steady and transient flows, and it measures both the steady and unsteady components of the surface heat flux. A version of the Heat Flux Microsensor has been developed to meet the harsh demands of combustion environments. These gages use platinum and platinum-10 percent rhodium as the thermoelectric materials. The thermal resistance layer is silicon monoxide and a protective coating of Al2O3 is deposited on top of the sensor. The superimposed thin-film pattern of all six layers is presented. The large pads are for connection with pins used to bring the signal out the back of the ceramic.

The Antarctic permafrost as a testbed for REMS (Rover Environmental Monitoring Station-Mars Science Laboratory)

NASA Astrophysics Data System (ADS)

Esteban, B.; Ramos, M.; Sebastián, E.; Armiens, C.; Gómez-Elvira, J.; Cabos, W.; de Pablo, M. A.

2009-04-01

The present climatic characteristics of Mars favor the presence of extense permafrost areas in this lonely planet. Therefore environmental parameters that are included in Martian Rover missions are also used for monitoring thermal soil surface evolution in order to study the permafrost active layer thickness and the energy balance in the soil-atmosphere boundary limit layer. The REMS (Rover Environmental Monitoring Station) is an environmental station designed by the Centro de Astrobiología (CAB- Spain) with the collaboration of national and international partners (CRISA/EADS, UPC and FMI), which is part of the payload of the MSL (Mars Science Laboratory) NASA mission to Mars (http://mars.jpl.nasa.gov/msl/overview/). This mission is expected to be launched in the final months of 2009, and mainly consists of a Rover, with a complete set of scientific instruments; the Rover will carry the biggest, most advanced suite of instruments for scientific studies ever sent to the Martian surface. Five sensors compose the REMS instrument: ground (GT-REMS) and air temperatures, wind speed and direction, pressure, humidity and ultraviolet radiation (UV-REMS). A simplified setup of the REMS was deployed on Antarctica in the surroundings of the Spanish Antarctic Stations on Livingston and Deception Islands (Maritime Antarctica), where the permafrost distribution is well-known. The aim of the experiment was to check REMS's sensors response against hard environmental conditions and calibrates their measures with standard Antarctic devices. The experimental apparatuses included some standard meteorological and thermopiles sensors corresponding to the REMS. All the sensors are mounted in a 1.8 m mast and include a Pt100 air temperature sensor with shield solar protection on the mast top, a Kipp and Zonnen CNR1 net radiometer for measuring infrared (5-50 μm) and short wave solar (305-2800 nm) radiation at 1.5 m high, GT-REMS sensor and its amplification box at 0.7 m high and finally two soil temperature plates based on Pt100 sensors are in close contact with the surface in the angle of view of the GT-REMS thermopiles. In this work, we present a preliminary analysis of the data obtained in the Antarctic field campaign 2008-2009. For the analysis we developed a theoretical model which is briefly outlined here. We also present the results of simulations carried out with the model and their validation against the antarctic data. Complementary to the Antarctic experiments, we carried out an experience with all the instruments during the last summer in the CAB-Spain which are also used in the analysis. Finally, we compare the results of the last polar and CAB experiments in order to check the improvements introduced in GT-REMS.

Measurement of a surface heat flux and temperature

NASA Technical Reports Server (NTRS)

Davis, R. M.; Antoine, G. J.; Diller, T. E.; Wicks, A. L.

1994-01-01

The Heat Flux Microsensor is a new sensor which was recently patented by Virginia Tech and is just starting to be marketed by Vatell Corp. The sensor is made using the thin-film microfabrication techniques directly on the material that is to be measured. It consists of several thin-film layers forming a differential thermopile across a thermal resistance layer. The measured heat flux q is proportional to the temperature difference across the resistance layer q= k(sub g)/delta(sub g) x (t(sub 1) - T(sub 2)), where k(sub g) is the thermal conductivity and delta (sub g) is the thickness of the thermal resistance layer. Because the gages are sputter coated directly onto the surface, their total thickness is less than 2 micrometers, which is two orders of magnitude thinner than previous gages. The resulting temperature difference across the thermal resistance layer (delta is less than 1 micrometer) is very small even at high heat fluxes. To generate a measurable signal many thermocouple pairs are put in series to form a differential thermopile. The combination of series thermocouple junctions and thin-film design creates a gage with very attractive characteristics. It is not only physically non-intrusive to the flow, but also causes minimal disruption of the surface temperature. Because it is so thin, the response time is less than 20 microsec. Consequently, the frequency response is flat from 0 to over 50 kHz. Moreover, the signal of the Heat Flux Microsensor is directly proportional to the heat flux. Therefore, it can easily be used in both steady and transient flows, and it measures both the steady and unsteady components of the surface heat flux. A version of the Heat Flux Microsensor has been developed to meet the harsh demands of combustion environments. These gages use platinum and platinum-10 percent rhodium as the thermoelectric materials. The thermal resistance layer is silicon monoxide and a protective coating of Al2O3 is deposited on top of the sensor. The superimposed thin-film pattern of all six layers is presented. The large pads are for connection with pins used to bring the signal out the back of the ceramic. In addition to the heat flux measurement, the surface temperature is measured with a platinum resistance layer (RTS). The resistance of this layer increases with increasing temperature. Therefore, these gages simultaneously measure the surface temperature and heat flux. The demonstrated applications include rocket nozzles, SCRAM jet engines, gas turbine engines, boiling heat transfer, flame experiments, basic fluid heat transfer, hypersonic flight, and shock tube testing. The laboratory involves using one of these sensors in a small combustion flame. The sensor is made on a 2.5 cm diameter piece of aluminum nitride ceramic.

Unsteady Heat-Flux Measurements of Second-Mode Instability Waves in a Hypersonic Boundary Layer

NASA Technical Reports Server (NTRS)

Kergerise, Michael A.; Rufer, Shann J.

2016-01-01

In this paper we report on the application of the atomic layer thermopile (ALTP) heat- flux sensor to the measurement of laminar-to-turbulent transition in a hypersonic flat plate boundary layer. The centerline of the flat-plate model was instrumented with a streamwise array of ALTP sensors and the flat-plate model was exposed to a Mach 6 freestream over a range of unit Reynolds numbers. Here, we observed an unstable band of frequencies that are associated with second-mode instability waves in the laminar boundary layer that forms on the flat-plate surface. The measured frequencies, group velocities, phase speeds, and wavelengths of these instability waves are in agreement with data previously reported in the literature. Heat flux time series, and the Morlet-wavelet transforms of them, revealed the wave-packet nature of the second-mode instability waves. In addition, a laser-based radiative heating system was developed to measure the frequency response functions (FRF) of the ALTP sensors used in the wind tunnel test. These measurements were used to assess the stability of the sensor FRFs over time and to correct spectral estimates for any attenuation caused by the finite sensor bandwidth.

Boundary layer separation and reattachment detection on airfoils by thermal flow sensors.

PubMed

Sturm, Hannes; Dumstorff, Gerrit; Busche, Peter; Westermann, Dieter; Lang, Walter

2012-10-24

A sensor concept for detection of boundary layer separation (flow separation, stall) and reattachment on airfoils is introduced in this paper. Boundary layer separation and reattachment are phenomena of fluid mechanics showing characteristics of extinction and even inversion of the flow velocity on an overflowed surface. The flow sensor used in this work is able to measure the flow velocity in terms of direction and quantity at the sensor's position and expected to determine those specific flow conditions. Therefore, an array of thermal flow sensors has been integrated (flush-mounted) on an airfoil and placed in a wind tunnel for measurement. Sensor signals have been recorded at different wind speeds and angles of attack for different positions on the airfoil. The sensors used here are based on the change of temperature distribution on a membrane (calorimetric principle). Thermopiles are used as temperature sensors in this approach offering a baseline free sensor signal, which is favorable for measurements at zero flow. Measurement results show clear separation points (zero flow) and even negative flow values (back flow) for all sensor positions. In addition to standard silicon-based flow sensors, a polymer-based flexible approach has been tested showing similar results.

Unsteady heat-flux measurements of second-mode instability waves in a hypersonic flat-plate boundary layer

NASA Astrophysics Data System (ADS)

Kegerise, Michael A.; Rufer, Shann J.

2016-08-01

In this paper, we report on the application of the atomic layer thermopile (ALTP) heat-flux sensor to the measurement of laminar-to-turbulent transition in a hypersonic flat-plate boundary layer. The centerline of the flat-plate model was instrumented with a streamwise array of ALTP sensors, and the flat-plate model was exposed to a Mach 6 freestream over a range of unit Reynolds numbers. Here, we observed an unstable band of frequencies that are associated with second-mode instability waves in the laminar boundary layer that forms on the flat-plate surface. The measured frequencies, group velocities, phase speeds, and wavelengths of these instability waves are consistent with data previously reported in the literature. Heat flux time series, and the Morlet wavelet transforms of them, revealed the wave-packet nature of the second-mode instability waves. In addition, a laser-based radiative heating system was used to measure the frequency response functions (FRF) of the ALTP sensors used in the wind tunnel test. These measurements were used to assess the stability of the sensor FRFs over time and to correct spectral estimates for any attenuation caused by the finite sensor bandwidth.

Boundary Layer Separation and Reattachment Detection on Airfoils by Thermal Flow Sensors

PubMed Central

Sturm, Hannes; Dumstorff, Gerrit; Busche, Peter; Westermann, Dieter; Lang, Walter

2012-01-01

A sensor concept for detection of boundary layer separation (flow separation, stall) and reattachment on airfoils is introduced in this paper. Boundary layer separation and reattachment are phenomena of fluid mechanics showing characteristics of extinction and even inversion of the flow velocity on an overflowed surface. The flow sensor used in this work is able to measure the flow velocity in terms of direction and quantity at the sensor's position and expected to determine those specific flow conditions. Therefore, an array of thermal flow sensors has been integrated (flush-mounted) on an airfoil and placed in a wind tunnel for measurement. Sensor signals have been recorded at different wind speeds and angles of attack for different positions on the airfoil. The sensors used here are based on the change of temperature distribution on a membrane (calorimetric principle). Thermopiles are used as temperature sensors in this approach offering a baseline free sensor signal, which is favorable for measurements at zero flow. Measurement results show clear separation points (zero flow) and even negative flow values (back flow) for all sensor positions. In addition to standard silicon-based flow sensors, a polymer-based flexible approach has been tested showing similar results. PMID:23202160

Temperature sensitivity of Eppley broadband radiometers

NASA Technical Reports Server (NTRS)

Smith, William L., Jr.; Cox, Stephen K.

1990-01-01

Broadband radiometers manufactured by Eppley Laboratories Inc. are commonly used to measure irradiance from both ground-based and aircraft platforms. Namely, the pyranometer (Model PSP) measures irradiance in the .3 to 3.0 micron spectral region while the pyrgeometer (Model PIR) senses energy in the 4 to 50 micron region. The two instruments have a similar thermopile construction but different filters to achieve the appropriate spectral selection. During the fall of 1986, the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE) commenced with the first cirrus Intensive Field Observation (IFO) conducted in Central Wisconsin. Due to the nature of this field project, pyranometers and pyrgeometers manufactured by Eppley were flown on NCAR's high altitude research aircraft, the Sabreliner. Inherent in the construction of these radiometers is temperature compensation circuitry designed to make the instrument sensitivity nominally constant over a temperature range from -20 to +40 C. Because the Sabreliner flew at high altitudes where temperatures were as cold as -70 C, it was necessary to determine the radiometers relative sensitivity to temperatures below -20 C and apply appropriate corrections to the FIRE radiation data set. A procedure to perform this calibration is outlined. It is meant to serve as a supplement to calibration procedures.

Research on the method of establishing the total radiation meter calibration device

NASA Astrophysics Data System (ADS)

Gao, Jianqiang; Xia, Ming; Xia, Junwen; Zhang, Dong

2015-10-01

Pyranometer is an instrument used to measure the solar radiation, according to pyranometer differs as installation state, can be respectively measured total solar radiation, reflected radiation, or with the help of shading device for measuring scattering radiation. Pyranometer uses the principle of thermoelectric effect, inductive element adopts winding plating type multi junction thermopile, its surface is coated with black coating with high absorption rate. Hot junction in the induction surface, while the cold junction is located in the body, the cold and hot junction produce thermoelectric potential. In the linear range, the output signal is proportional to the solar irradiance. Traceability to national meteorological station, as the unit of the national legal metrology organizations, the responsibility is to transfer value of the sun and the earth radiation value about the national meteorological industry. Using the method of comparison, with indoor calibration of solar simulator, at the same location, standard pyranometer and measured pyranometer were alternately measured radiation irradiance, depending on the irradiation sensitivity standard pyranometer were calculated the radiation sensitivity of measured pyranometer. This paper is mainly about the design and calibration method of the pyranometer indoor device. The uncertainty of the calibration result is also evaluated.

National Renewable Energy Laboratory Pyrheliometer Comparisons: 24 September - 5 October 2012 (NPC-2012)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoffel, T.; Reda, I.

2013-05-01

The NREL Pyrheliometer Comparisons for 2012 (NPC-2012) were held at the Solar Radiation Research Laboratory in Golden, Colorado, from September 24 through October 5 for the purpose of transferring the World Radiometric Reference (WRR) to participating instrument. Twenty scientists and engineers operated 32 absolute cavity radiometers and 18 conventional thermopile-based pyrheliometers to simultaneously measure clear-sky direct normal irradiance during the comparisons. The transfer standard group of reference radiometers for NPC-2012 consisted of four NREL radiometers with direct traceability to the WRR, having participated in the Eleventh International Pyrheliometer Comparisons (IPC-XI) hosted by the World Radiation Center in the fall ofmore » 2010. As the result of NPC-2012, each participating absolute cavity radiometer was assigned a new WRR transfer factor, computed as the reference irradiance computed by the transfer standard group divided by the observed irradiance from the participating radiometer. The performance of the transfer standard group during NPC-2012 was consistent with previous comparisons, including IPC-XI. The measurement performance of the transfer standard group allowed the transfer of the WRR to each participating radiometer with an estimated uncertainty of +/- 0.33% with respect to the International System of Units.« less

A micro dew point sensor with a thermal detection principle

NASA Astrophysics Data System (ADS)

Kunze, M.; Merz, J.; Hummel, W.-J.; Glosch, H.; Messner, S.; Zengerle, R.

2012-01-01

We present a dew point temperature sensor with the thermal detection of condensed water on a thin membrane, fabricated by silicon micromachining. The membrane (600 × 600 × ~1 µm3) is part of a silicon chip and contains a heating element as well as a thermopile for temperature measurement. By dynamically heating the membrane and simultaneously analyzing the transient increase of its temperature it is detected whether condensed water is on the membrane or not. To cool the membrane down, a peltier cooler is used and electronically controlled in a way that the temperature of the membrane is constantly held at a value where condensation of water begins. This temperature is measured and output as dew point temperature. The sensor system works in a wide range of dew point temperatures between 1 K and down to 44 K below air temperature. In experimental investigations it could be proven that the deviation of the measured dew point temperatures compared to reference values is below ±0.2 K in an air temperature range of 22 to 70 °C. At low dew point temperatures of -20 °C (air temperature = 22 °C) the deviation increases to nearly -1 K.

Buoyancy Effects in Strongly-Pulsed, Turbulent Diffusion Flames

NASA Technical Reports Server (NTRS)

Hermanson, J. C.; Johari, H.; Ghaem-Maghami, E.; Stocker, D. P.; Hegde, U. G.

2004-01-01

The objective of this experiment is to better understand the combustion behavior of pulsed, turbulent diffusion flames by conducting experiments in microgravity. The fuel jet is fully-modulated (i.e., completely shut off between pulses) by an externally controlled valve system leading to enhanced fuel/air mixing compared to acoustically excited or partially-modulated jets. Experiments are conducted both in laboratories at UW and WPI and in the GRC 2.2s Drop Tower. A single fuel nozzle with diameter d = 2 mm is centered in a combustor 20 20 cm in cross section and 67 cm in height. The gaseous fuel flow (ethylene or a 50/50 ethylene/nitrogen mixture by volume) is fully-modulated by a fast-response solenoid valve with injection times from tau = 4 to tau = 300 ms. The nominal Reynolds number based on the fuel velocity during injection, U(sub jet), is 5,000. A slow oxidizer co-flow properly ventilates the flame and an electrically heated wire loop serves as a continuous ignition source. Diagnostic techniques include video imaging, fine-wire thermocouples and thermopile radiometers, and gas sampling and standard emissions instruments (the last in the laboratory only).

Buoyancy Effects in Strongly-pulsed, Turbulent Diffusion Flames

NASA Technical Reports Server (NTRS)

Hermanson, J. C.; Johari, H.; Ghaem-Maghami, E.; Stocker, D. P.; Hegde, U. G.

2004-01-01

The objective of this experiment is to better understand the combustion behavior of pulsed, turbulent diffusion flames by conducting experiments in microgravity. The fuel jet is fully-modulated (i.e., completely shut off between pulses) by an externally controlled valve system leading to enhanced fuel/air mixing compared to acoustically excited or partially-modulated jets. Experiments are conducted both in laboratories at UW and WPI and in the GRC 2.2s Drop Tower. A single fuel nozzle with diameter d = 2 mm is centered in a combustor 20 x 20 cm in cross section and 67 cm in height. The gaseous fuel flow (ethylene or a 50/50 ethylene/nitrogen mixture by volume) is fully-modulated by a fast-response solenoid valve with injection times from tau = 4 to tau = 300 ms. The nominal Reynolds number based on the fuel velocity during injection, U(sub jet), is 5,000. A slow oxidizer co-flow properly ventilates the flame and an electrically heated wire loop serves as a continuous ignition source. Diagnostic techniques include video imaging, fine-wire thermocouples and thermopile radiometers, and gas sampling and standard emissions instruments (the last in the laboratory only).

Cassini infrared Fourier spectroscopic investigation

NASA Astrophysics Data System (ADS)

Kunde, Virgil G.; Ade, Peter A.; Barney, Richard D.; Bergman, D.; Bonnal, Jean-Francois; Borelli, R.; Boyd, D.; Brasunas, John C.; Brown, G.; Calcutt, S. B.; Carroll, F.; Courtin, R.; Cretolle, Jacky; Crooke, Julie A.; Davis, Martin A.; Edberg, S.; Fettig, R.; Flasar, M.; Glenar, David A.; Graham, S.; Hagopian, John G.; Hakun, C. F.; Hayes, Patricia A.; Herath, L.; Horn, Linda; Jennings, Donald E.; Karpati, G.; Kellebenz, C.; Lakew, Brook; Lindsay, J.; Lohr, J.; Lyons, James J.; Martineau, Robert J.; Martino, Anthony J.; Matsumura, M.; McCloskey, J.; Melak, T.; Michel, G.; Morell, Armando; Mosier, C.; Pack, L.; Plants, M.; Robinson, D.; Rodriguez, Louis; Romani, Paul; Schaefer, W. J.; Schmidt, Steve; Trujillo, C.; Vellacott, Tim; Wagner, K.; Yun, D.

1996-10-01

The composite infrared spectrometer (CIRS) is a remote sensing instrument to be flown on the Cassini orbiter. CIRS will retrieve vertical profiles of temperature and gas composition for the atmospheres of Titan and Saturn, from deep in their tropospheres to high in their stratospheres. CIRS will also retrieve information on the thermal properties and composition of Saturn's rings and Saturnian satellites. CIRS consists of a pair of Fourier Transform Spectrometers (FTSs) which together cover the spectral range from 10-1400 cm-1 with a spectral resolution up to 0.5 cm-1. The two interferometers share a 50 cm beryllium Cassegrain telescope. The far-infrared FTS is a polarizing interferometer covering the 10-600 cm-1 range with a pair of thermopile detectors, and a 3.9 mrad field of view. The mid-infrared FTS is a conventional Michelson interferometer covering 200-1400 cm-1 in two spectral bandpasses: 600-1100 cm- 1100-1400 cm(superscript -1 with a 1 by 10 photovoltaic HgCdTe array. Each pixel of the arrays has an approximate 0.3 mrad field of view. The HgCdTe arrays are cooled to approximately 80K with a passive radiative cooler.

Field Measured Spectral Albedo-Four Years of Data from the Western U.S. Prairie

NASA Astrophysics Data System (ADS)

Michalsky, Joseph J.; Hodges, Gary B.

2013-01-01

This paper presents an initial look at four years of spectral measurements used to calculate albedo for the Colorado prairie just east of the Rocky Mountain range foothills. Some issues associated with calculating broadband albedo from thermopile sensors are discussed demonstrating that uncorrected instrument issues have led to incorrect conclusions. Normalized Difference Vegetative Index (NDVI) is defined for the spectral instruments in this study and used to demonstrate the dramatic changes that can be monitored with this very sensitive product. Examples of albedo wavelength and solar-zenith angle dependence for different stages of vegetative growth and senescence are presented. The spectral albedo of fresh snow and its spectral and solar-zenith angle dependence are discussed and contrasted with other studies of these dependencies. We conclude that fresh snow is consistent with a Lambertian reflector over the solar incidence angles measured; this is contrary to most snow albedo results. Even a slope of a degree or two in the viewed surface can explain the asymmetry in the morning and afternoon albedos for snow and vegetation. Plans for extending these spectral measurements for albedo to longer wavelengths and to additional sites are described.

Simplified Method for the Characterization of Rectangular Straw Bales (RSB) Thermal Conductivity

NASA Astrophysics Data System (ADS)

Conti, Leonardo; Goli, Giacomo; Monti, Massimo; Pellegrini, Paolo; Rossi, Giuseppe; Barbari, Matteo

2017-10-01

This research aims to design and implement tools and methods focused at the assessment of the thermal properties of full size Rectangular Straw Bales (RSB) of various nature and origin, because their thermal behaviour is one of the key topics in market development of sustainable building materials. As a first approach a method based on a Hot-Box in agreement with the ASTM C1363 - 11 standard was adopted. This method was found to be difficult for the accurate measurement of energy flows. Instead, a method based on a constant energy input was developed. With this approach the thermal conductivity of a Rectangular Straw-Bale (RSB λ) can be determined by knowing the thermal conductivity of the materials used to build the chamber and the internal and external temperature of the samples and of the chamber. A measurement a metering chamber was built and placed inside a climate chamber, maintained at constant temperature. A known quantity of energy was introduced inside the metering chamber. A series of thermopiles detects the temperature of the internal and external surfaces of the metering chamber and of the specimens allowing to calculate the thermal conductivity of RSB in its natural shape. Different cereal samples were tested. The values were found consistent with those published in scientific literature.

Method to Calculate Uncertainty Estimate of Measuring Shortwave Solar Irradiance using Thermopile and Semiconductor Solar Radiometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reda, I.

2011-07-01

The uncertainty of measuring solar irradiance is fundamentally important for solar energy and atmospheric science applications. Without an uncertainty statement, the quality of a result, model, or testing method cannot be quantified, the chain of traceability is broken, and confidence cannot be maintained in the measurement. Measurement results are incomplete and meaningless without a statement of the estimated uncertainty with traceability to the International System of Units (SI) or to another internationally recognized standard. This report explains how to use International Guidelines of Uncertainty in Measurement (GUM) to calculate such uncertainty. The report also shows that without appropriate corrections tomore » solar measuring instruments (solar radiometers), the uncertainty of measuring shortwave solar irradiance can exceed 4% using present state-of-the-art pyranometers and 2.7% using present state-of-the-art pyrheliometers. Finally, the report demonstrates that by applying the appropriate corrections, uncertainties may be reduced by at least 50%. The uncertainties, with or without the appropriate corrections might not be compatible with the needs of solar energy and atmospheric science applications; yet, this report may shed some light on the sources of uncertainties and the means to reduce overall uncertainty in measuring solar irradiance.« less

Low-cost, compact, and robust gas abundance sensor package

NASA Astrophysics Data System (ADS)

Tran, Dat; Nehmetallah, George; Gorius, Nicolas; Ferguson, Frank T.; Esper, Jaime; Johnson, Natasha M.; Aslam, Shahid; Nixon, Conor

2018-05-01

Gas Abundance Sensor Package (GASP) is a stand-alone scientific instrument that has the capability to measure the concentration of target gases based on a non-dispersive infrared sensor system along with atmospheric reference parameters. The main objective of this work is to develop a GASP system which takes advantage of available technologies and off-the-shelf components to provide a cost-effective solution for localized sampling of gas concentrations. GASP will enable scientists to study the atmosphere and will identify the conditions of the target's planetary local environment. Moreover, due to a recent trend of miniaturization of electronic components and thermopiles detectors, a small size and robust instrument with a reduction in power consumption is developed in this work. This allows GASP to be easily integrated into a variety of small space vehicles such as CubeSats or small satellite system, especially the Micro-Reentry Capsule (MIRCA) prototype vehicle. This prototype is one of the most advanced concepts of small satellites that has the capability to survive the rapid dive into the atmosphere of a planet. In this paper, a fully-operational instrument system will be developed and tested in the laboratory environment as well as flight preparation for a field test of the instrument suite will be described.

Design and Characterization of a High Resolution Microfluidic Heat Flux Sensor with Thermal Modulation

PubMed Central

Nam, Sung-Ki; Kim, Jung-Kyun; Cho, Sung-Cheon; Lee, Sun-Kyu

2010-01-01

A complementary metal-oxide semiconductor-compatible process was used in the design and fabrication of a suspended membrane microfluidic heat flux sensor with a thermopile for the purpose of measuring the heat flow rate. The combination of a thirty-junction gold and nickel thermoelectric sensor with an ultralow noise preamplifier, a low pass filter, and a lock-in amplifier can yield a resolution 20 nW with a sensitivity of 461 V/W. The thermal modulation method is used to eliminate low-frequency noise from the sensor output, and various amounts of fluidic heat were applied to the sensor to investigate its suitability for microfluidic applications. For sensor design and analysis of signal output, a method of modeling and simulating electro-thermal behavior in a microfluidic heat flux sensor with an integrated electronic circuit is presented and validated. The electro-thermal domain model was constructed by using system dynamics, particularly the bond graph. The electro-thermal domain system model in which the thermal and the electrical domains are coupled expresses the heat generation of samples and converts thermal input to electrical output. The proposed electro-thermal domain system model is in good agreement with the measured output voltage response in both the transient and the steady state. PMID:22163568

Large anomalous Nernst effect at room temperature in a chiral antiferromagnet

NASA Astrophysics Data System (ADS)

Ikhlas, Muhammad; Tomita, Takahiro; Koretsune, Takashi; Suzuki, Michi-To; Nishio-Hamane, Daisuke; Arita, Ryotaro; Otani, Yoshichika; Nakatsuji, Satoru

2017-11-01

A temperature gradient in a ferromagnetic conductor can generate a transverse voltage drop perpendicular to both the magnetization and heat current. This anomalous Nernst effect has been considered to be proportional to the magnetization, and thus observed only in ferromagnets. Theoretically, however, the anomalous Nernst effect provides a measure of the Berry curvature at the Fermi energy, and so may be seen in magnets with no net magnetization. Here, we report the observation of a large anomalous Nernst effect in the chiral antiferromagnet Mn 3Sn (ref. ). Despite a very small magnetization ~0.002 μB per Mn, the transverse Seebeck coefficient at zero magnetic field is ~0.35 μV K-1 at room temperature and reaches ~0.6 μV K-1 at 200 K, which is comparable to the maximum value known for a ferromagnetic metal. Our first-principles calculations reveal that this arises from a significantly enhanced Berry curvature associated with Weyl points near the Fermi energy. As this effect is geometrically convenient for thermoelectric power generation--it enables a lateral configuration of modules to cover a heat source--these observations suggest that a new class of thermoelectric materials could be developed that exploit topological magnets to fabricate efficient, densely integrated thermopiles.

Variability of pulsed energy outputs from three dermatology lasers during multiple simulated treatments.

PubMed

Britton, Jason

2018-01-20

Dermatology laser treatments are undertaken at regional departments using lasers of different powers and wavelengths. In order to achieve good outcomes, there needs to be good consistency of laser output across different weeks as it is custom and practice to break down the treatments into individual fractions. Departments will also collect information from test patches to help decide on the most appropriate treatment parameters for individual patients. The objective of these experiments is to assess the variability of the energy outputs from a small number of lasers across multiple weeks at realistic parameters. The energy outputs from 3 lasers were measured at realistic treatment parameters using a thermopile detector across a period of 6 weeks. All lasers fired in single-pulse mode demonstrated good repeatability of energy output. In spite of one of the lasers being scheduled for a dye canister change in the next 2 weeks, there was good energy matching between the two devices with only a 4%-5% variation in measured energies. Based on the results presented, clinical outcomes should not be influenced by variability in the energy outputs of the dermatology lasers used as part of the treatment procedure. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Passive exposure of Earth radiation budget experiment components LDEF experiment AO-147: Post-flight examinations and tests

NASA Technical Reports Server (NTRS)

Hickey, John R.

1991-01-01

The Passive Exposure of Earth Radiation Budget Experiment Components (PEERBEC) experiment of the Long Duration Exposure Facility (LDEF) mission was composed of sensors and components associated with the measurement of the earth radiation budget (ERB) from satellites. These components included the flight spare sensors from the ERB experiment which operated on Nimbus 6 and 7 satellites. The experiment components and materials as well as the pertinent background and ancillary information necessary for the understanding of the intended mission and the results are described. The extent and timing of the LDEF mission brought the exposure from solar minimum between cycles 21 and 22 through the solar maximum of cycle 22. The orbital decay, coupled with the events of solar maximum, caused the LDEF to be exposed to a broader range of space environmental effects than were anticipated. The mission spanned almost six years concurrent with the 12 year (to date) Nimbus 7 operations. Preliminary information is presented on the following: (1) the changes in transmittance experienced by the interference filters; (2) the results of retesting of the thermopile sensors, which appear to be relatively unaffected by the exposure; and (3) the results of the recalibration of the APEX cavity radiometer. The degradation and recovery of the filters of the Nimbus 7 ERB are also discussed relative to the apparent atomic oxygen cleaning which also applies to the LDEF.

Characterization of Pu-238 Heat Source Granule Containment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richardson, Paul Dean II; Sanchez, Joey Leo; Wall, Angelique Dinorah

The Milliwatt Radioisotopic Themoelectric Generator (RTG) provides power for permissive-action links. Essentially these are nuclear batteries that convert thermal energy to electrical energy using a doped silicon-germanium thermopile. The thermal energy is provided by a heat source made of 238Pu, in the form of 238PuO 2 granules. The granules are contained by 3 layers of encapsulation. A thin T-111 liner surrounds the 238PuO 2 granules and protects the second layer (strength member) from exposure to the fuel granules. An outer layer of Hastalloy-C protects the T-111 from oxygen embrittlement. The T-111 strength member is considered the critical component in thismore » 238PuO 2 containment system. Any compromise in the strength member seen during destructive testing required by the RTG surveillance program is characterized. The T-111 strength member is characterized through Scanning Electron Microscopy (SEM), and Metallography. SEM is used in the Secondary Electron mode to reveal possible grain boundary deformation and/or cracking in the region of the strength member weld. Deformation and cracking uncovered by SEM are further characterized by Metallography. Metallography sections are mounted and polished, observed using optical microscopy, then documented in the form of microphotographs. SEM mat further be used to examine polished Metallography mounts to characterize elements using the SEM mode of Energy Dispersive X-ray spectroscopy (EDS).« less

A cavity radiometer for Earth albedo measurement, phase 1

NASA Technical Reports Server (NTRS)

1987-01-01

Radiometric measurements of the directional albedo of the Earth requires a detector with a flat response from 0.2 to 50 microns, a response time of about 2 seconds, a sensitivity of the order of 0.02 mw/sq cm, and a measurement uncertainty of less than 5 percent. Absolute cavity radiometers easily meet the spectral response and accuracy requirements for Earth albedo measurements, but the radiometers available today lack the necessary sensitivity and response time. The specific innovations addressed were the development of a very low thermal mass cavity and printed/deposited thermocouple sensing elements which were incorporated into the radiometer design to produce a sensitive, fast response, absolute radiometer. The cavity is applicable to the measurement of the reflected and radiated fluxes from the Earth surface and lower atmosphere from low Earth orbit satellites. The effort consisted of requirements and thermal analysis; design, construction, and test of prototype elements of the black cavity and sensor elements to show proof-of-concept. The results obtained indicate that a black body cavity sensor that has inherently a flat response from 0.2 to 50 microns can be produced which has a sensitivity of at least 0.02 mw/sq cm per micro volt ouput and with a time constant of less than two seconds. Additional work is required to develop the required thermopile.

Laser-induced voltages at room temperature in YBa{sub 2}Cu{sub 3}O{sub 7} and Pr{sub x}Y{sub 1{minus}x}Ba{sub 2}Cu{sub 3}O{sub 7} thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habermeier, H.U.; Jisrawi, N.; Jaeger-Waldau, G.

Recent reports on high transient transverse voltages at room temperature in YBa{sub 2}Cu{sub 3}O{sub 7} and Pr{sub x}Y{sub 1{minus}x}Ba{sub 2}Cu{sub 3}O{sub 7} thin films grown on SrTiO{sub 3} single crystal substrates, with a tilt angle between the [001] cubic axis and the substrate surface plane, have been interpreted by thermoelectric fields transverse to a laser-induced temperature gradient which are caused by the non-zero off diagonal elements of the Seebeck tensor. The authors have studied this effect in epitaxially grown Pr-doped, as well as undoped YBa{sub 2}Cu{sub 3}O{sub 7}, thin films and observed for a 2 mm long YBa{sub 2}Cu{sub 3}O{submore » 7} strip exposed to a UV photon fluence of 100 mJ/cm{sup 2} signals as large as 30 V. The unexpected high values for the signals and their doping dependence are discussed within the frame of a model based on a thermopile arrangement, the growth induced defect structure and the doping induced modifications of the material properties.« less

Development of on-line laser power monitoring system

NASA Astrophysics Data System (ADS)

Ding, Chien-Fang; Lee, Meng-Shiou; Li, Kuan-Ming

2016-03-01

Since the laser was invented, laser has been applied in many fields such as material processing, communication, measurement, biomedical engineering, defense industries and etc. Laser power is an important parameter in laser material processing, i.e. laser cutting, and laser drilling. However, the laser power is easily affected by the environment temperature, we tend to monitor the laser power status, ensuring there is an effective material processing. Besides, the response time of current laser power meters is too long, they cannot measure laser power accurately in a short time. To be more precisely, we can know the status of laser power and help us to achieve an effective material processing at the same time. To monitor the laser power, this study utilize a CMOS (Complementary metal-oxide-semiconductor) camera to develop an on-line laser power monitoring system. The CMOS camera captures images of incident laser beam after it is split and attenuated by beam splitter and neutral density filter. By comparing the average brightness of the beam spots and measurement results from laser power meter, laser power can be estimated. Under continuous measuring mode, the average measuring error is about 3%, and the response time is at least 3.6 second shorter than thermopile power meters; under trigger measuring mode which enables the CMOS camera to synchronize with intermittent laser output, the average measuring error is less than 3%, and the shortest response time is 20 millisecond.

Mexican national pyronometer network calibration

NASA Astrophysics Data System (ADS)

VAldes, M.; Villarreal, L.; Estevez, H.; Riveros, D.

2013-12-01

In order to take advantage of the solar radiation as an alternate energy source it is necessary to evaluate the spatial and temporal availability. The Mexican National Meterological Service (SMN) has a network with 136 meteorological stations, each coupled with a pyronometer for measuring the global solar radiation. Some of these stations had not been calibrated in several years. The Mexican Department of Energy (SENER) in order to count on a reliable evaluation of the solar resource funded this project to calibrate the SMN pyrometer network and validate the data. The calibration of the 136 pyronometers by the intercomparison method recommended by the World Meterological Organization (WMO) requires lengthy observations and specific environmental conditions such as clear skies and a stable atmosphere, circumstances that determine the site and season of the calibration. The Solar Radiation Section of the Instituto de Geofísica of the Universidad Nacional Autónoma de México is a Regional Center of the WMO and is certified to carry out the calibration procedures and emit certificates. We are responsible for the recalibration of the pyronometer network of the SMN. A continuous emission solar simulator with exposed areas with 30cm diameters was acquired to reduce the calibration time and not depend on atmospheric conditions. We present the results of the calibration of 10 thermopile pyronometers and one photovoltaic cell by the intercomparison method with more than 10000 observations each and those obtained with the solar simulator.

An improved maximum permissible exposure meter for safety assessments of laser radiation

NASA Astrophysics Data System (ADS)

Corder, D. A.; Evans, D. R.; Tyrer, J. R.

1997-12-01

Current interest in laser radiation safety requires demonstration that a laser system has been designed to prevent exposure to levels of laser radiation exceeding the Maximum Permissible Exposure. In some simple systems it is possible to prove this by calculation, but in most cases it is preferable to confirm calculated results with a measurement. This measurement may be made with commercially available equipment, but there are limitations with this approach. A custom designed instrument is presented in which the full range of measurement issues have been addressed. Important features of the instrument are the design and optimisation of detector heads for the measurement task, and consideration of user interface requirements. Three designs for detector head are presented, these cover the majority of common laser types. Detector heads are designed to optimise the performance of relatively low cost detector elements for this measurement task. The three detector head designs are suitable for interfacing to photodiodes, low power thermopiles and pyroelectric detectors. Design of the user interface was an important aspect of the work. A user interface which is designed for the specific application minimises the risk of user error or misinterpretation of the measurement results. A palmtop computer was used to provide an advanced user interface. User requirements were considered in order that the final implement was well matched to the task of laser radiation hazard audits.

Method and apparatus for determining vertical heat flux of geothermal field

DOEpatents

Poppendiek, Heinz F.

1982-01-01

A method and apparatus for determining vertical heat flux of a geothermal field, and mapping the entire field, is based upon an elongated heat-flux transducer (10) comprised of a length of tubing (12) of relatively low thermal conductivity with a thermopile (20) inside for measuring the thermal gradient between the ends of the transducer after it has been positioned in a borehole for a period sufficient for the tube to reach thermal equilibrium. The transducer is thermally coupled to the surrounding earth by a fluid annulus, preferably water or mud. A second transducer comprised of a length of tubing of relatively high thermal conductivity is used for a second thermal gradient measurement. The ratio of the first measurement to the second is then used to determine the earth's thermal conductivity, k.sub..infin., from a precalculated graph, and using the value of thermal conductivity thus determined, then determining the vertical earth temperature gradient, b, from predetermined steady state heat balance equations which relate the undisturbed vertical earth temperature distributions at some distance from the borehole and earth thermal conductivity to the temperature gradients in the transducers and their thermal conductivity. The product of the earth's thermal conductivity, k.sub..infin., and the earth's undisturbed vertical temperature gradient, b, then determines the earth's vertical heat flux. The process can be repeated many times for boreholes of a geothermal field to map vertical heat flux.

Nano-Calorimetry based point of care biosensor for metabolic disease management.

PubMed

Kazura, Evan; Lubbers, Brad R; Dawson, Elliott; Phillips, John A; Baudenbacher, Franz

2017-09-01

Point of care (POC) diagnostics represents one of the fastest growing health care technology segments. Developments in microfabrication have led to the development of highly-sensitive nanocalorimeters ideal for directly measuring heat generated in POC biosensors. Here we present a novel nano-calorimeter-based biosensor design with differential sensing to eliminate common mode noise and capillary microfluidic channels for sample delivery to the thermoelectric sensor. The calorimeter has a resolution of 1.4 ± 0.2 nJ/(Hz) 1/2 utilizing a 27 junction bismuth/titanium thermopile, with a total Seebeck coefficient of 2160 μV/K. Sample is wicked to the calorimeter through a capillary channel making it suitable for monitoring blood obtained through a finger prick (<1 μL sample required). We demonstrate device performance in a model assay using catalase, achieving a threshold for hydrogen peroxide quantification of 50 μM. The potential for our device as a POC blood test for metabolic diseases is shown through the quantification of phenylalanine (Phe) in serum, an unmet necessary service in the management of Phenylketonuria (PKU). Pegylated phenylalanine ammonia-lyase (PEG-PAL) was utilized to react with Phe, but reliable detection was limited to <5 mM due to low enzymatic activity. The POC biosensor concept can be multiplexed and adapted to a large number of metabolic diseases utilizing different immobilized enzymes.

Evaluation of a newly developed mid-infrared sensor for real-time monitoring of yeast fermentations.

PubMed

Schalk, Robert; Geoerg, Daniel; Staubach, Jens; Raedle, Matthias; Methner, Frank-Juergen; Beuermann, Thomas

2017-05-01

A mid-infrared (MIR) sensor using the attenuated total reflection (ATR) technique has been developed for real-time monitoring in biotechnology. The MIR-ATR sensor consists of an IR emitter as light source, a zinc selenide ATR prism as boundary to the process, and four thermopile detectors, each equipped with an optical bandpass filter. The suitability of the sensor for practical application was tested during aerobic batch-fermentations of Saccharomyces cerevisiae by simultaneous monitoring of glucose and ethanol. The performance of the sensor was compared to a commercial Fourier transform mid-infrared (FT-MIR) spectrometer by on-line measurements in a bypass loop. Sensor and spectrometer were calibrated by multiple linear regression (MLR) in order to link the measured absorbance in the transmission ranges of the four optical sensor channels to the analyte concentrations. For reference analysis, high-performance liquid chromatography (HPLC) was applied. Process monitoring using the sensor yielded in standard errors of prediction (SEP) of 6.15 g/L and 1.36 g/L for glucose and ethanol. In the case of the FT-MIR spectrometer the corresponding SEP values were 4.34 g/L and 0.61 g/L, respectively. The advantages of optical multi-channel mid-infrared sensors in comparison to FT-MIR spectrometer setups are the compactness, easy process implementation and lower price. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Assessment of Uncertainties for the NIST 1016 mm Guarded-Hot-Plate Apparatus: Extended Analysis for Low-Density Fibrous-Glass Thermal Insulation.

PubMed

Zarr, Robert R

2010-01-01

An assessment of uncertainties for the National Institute of Standards and Technology (NIST) 1016 mm Guarded-Hot-Plate apparatus is presented. The uncertainties are reported in a format consistent with current NIST policy on the expression of measurement uncertainty. The report describes a procedure for determination of component uncertainties for thermal conductivity and thermal resistance for the apparatus under operation in either the double-sided or single-sided mode of operation. An extensive example for computation of uncertainties for the single-sided mode of operation is provided for a low-density fibrous-glass blanket thermal insulation. For this material, the relative expanded uncertainty for thermal resistance increases from 1 % for a thickness of 25.4 mm to 3 % for a thickness of 228.6 mm. Although these uncertainties have been developed for a particular insulation material, the procedure and, to a lesser extent, the results are applicable to other insulation materials measured at a mean temperature close to 297 K (23.9 °C, 75 °F). The analysis identifies dominant components of uncertainty and, thus, potential areas for future improvement in the measurement process. For the NIST 1016 mm Guarded-Hot-Plate apparatus, considerable improvement, especially at higher values of thermal resistance, may be realized by developing better control strategies for guarding that include better measurement techniques for the guard gap thermopile voltage and the temperature sensors.

Assessment of Uncertainties for the NIST 1016 mm Guarded-Hot-Plate Apparatus: Extended Analysis for Low-Density Fibrous-Glass Thermal Insulation

PubMed Central

Zarr, Robert R.

2010-01-01

An assessment of uncertainties for the National Institute of Standards and Technology (NIST) 1016 mm Guarded-Hot-Plate apparatus is presented. The uncertainties are reported in a format consistent with current NIST policy on the expression of measurement uncertainty. The report describes a procedure for determination of component uncertainties for thermal conductivity and thermal resistance for the apparatus under operation in either the double-sided or single-sided mode of operation. An extensive example for computation of uncertainties for the single-sided mode of operation is provided for a low-density fibrous-glass blanket thermal insulation. For this material, the relative expanded uncertainty for thermal resistance increases from 1 % for a thickness of 25.4 mm to 3 % for a thickness of 228.6 mm. Although these uncertainties have been developed for a particular insulation material, the procedure and, to a lesser extent, the results are applicable to other insulation materials measured at a mean temperature close to 297 K (23.9 °C, 75 °F). The analysis identifies dominant components of uncertainty and, thus, potential areas for future improvement in the measurement process. For the NIST 1016 mm Guarded-Hot-Plate apparatus, considerable improvement, especially at higher values of thermal resistance, may be realized by developing better control strategies for guarding that include better measurement techniques for the guard gap thermopile voltage and the temperature sensors. PMID:27134779

Characterization of Pu-238 heat source granule containment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richardson Ii, P D; Thronas, D L; Romero, J P

2008-01-01

The Milliwatt Radioisotopic Thermoelectric Generator (RTG) provides power for permissive-action links. These nuclear batteries convert thermal energy to electrical energy using a doped silicon-germanium thermopile. The thermal energy is provided by a heat source made of {sup 238}Pu, in the form of {sup 238}PuO{sub 2} granules. The granules are contained in 3 layers of encapsulation. A thin T-111 liner surrounds the {sup 238}PuO{sub 2} granules and protects the second layer (strength member) from exposure to the fuel granules. The T-111 strength member contains the fuel under impact condition. An outer clad of Hastelloy-C protects the T-111 from oxygen embrittlement. Themore » T-111 strength member is considered the critical component in this {sup 238}PuO{sub 2} containment system. Any compromise in the strength member is something that needs to be characterized. Consequently, the T-111 strength member is characterized upon it's decommissioning through Scanning Electron Microscopy (SEM), and Metallography. SEM is used in Secondary Electron mode to reveal possible grain boundary deformation and/or cracking in the region of the strength member weld. Deformation and cracking uncovered by SEM are further characterized by Metallography. Metallography sections are mounted and polished, observed using optical microscopy, then documented in the form of photomicrographs. SEM may further be used to examine polished Metallography mounts to characterize elements using the SEM mode of Energy Dispersive X-ray Spectroscopy (EDS). This paper describes the characterization of the metallurgical condition of decommissioned RTG heat sources.« less

Miniaturized multi channel infrared optical gas sensor system

NASA Astrophysics Data System (ADS)

Wöllenstein, Jürgen; Eberhardt, Andre; Rademacher, Sven; Schmitt, Katrin

2011-06-01

Infrared spectroscopy uses the characteristic absorption of the molecules in the mid infrared and allows the determination of the gases and their concentration. Especially by the absorption at longer wavelengths between 8 μm and 12 μm, the so called "fingerprint" region, the molecules can be measured with highest selectivity. We present an infrared optical filter photometer for the analytical determination of trace gases in the air. The challenge in developing the filter photometer was the construction of a multi-channel system using a novel filter wheel concept - which acts as a chopper too- in order to measure simultaneously four gases: carbon monoxide, carbon dioxide, methane and ammonia. The system consists of a broadband infrared emitter, a long path cell with 1.7m optical path length, a filter wheel and analogue and digital signal processing. Multi channel filter photometers normally need one filter and one detector per target gas. There are small detection units with one, two or more detectors with integrated filters available on the market. One filter is normally used as reference at a wavelength without any cross-sensitivities to possible interfering gases (e.g. at 3.95 μm is an "atmospheric window" - a small spectral band without absorbing gases in the atmosphere). The advantage of a filter-wheel set-up is that a single IR-detector can be used, which reduces the signal drift enormously. Pyroelectric and thermopile detectors are often integrated in these kinds of spectrometers. For both detector types a modulation of the light is required and can be done - without an additional chopper - with the filter wheel.

Determination of the Thermal Offset of the Eppley Precision Spectral Pyranometer

NASA Technical Reports Server (NTRS)

Haeffelin, Martial; Kato, Seiji; Smith, Amie M.; Rutledge, C. Ken; Charlock, Thomas P.; Mahan, J. Robert

2001-01-01

Eppley's precision spectral pyranometer (PSP) is used in networks around the world to measure downwelling diffuse and global solar irradiance at the surface of the Earth. In recent years several studies have shown significant discrepancy between irradiances measured by pyranometers and those computed by atmospheric radiative transfer models. Pyranometer measurements have been questioned because observed diffuse irradiances sometimes are below theoretical minimum values for a pure molecular atmosphere, and at night the instruments often produce nonzero signals ranging between + 5 and - 10 W/sq m. We install thermistor sondes in the body of a PSP as well as on its inner dome to monitor the temperature gradients within the instrument, and we operate a pyrgeometer (PIR) instrument side by side with the PSP. We derive a relationship between the PSP output and thermal radiative exchange by the dome and the detector and a relationship between the PSP output and the PIR thermopile output (net-IR). We determine the true PSP offset by quickly capping the instrument at set time intervals. For a ventilated and shaded PSP, the thermal offset can reach - 15 W/sq m under clear skies, whereas it remains close to zero for low overcast clouds. We estimate the PSP thermal offset by two methods: (1) using the PSP temperatures and (2) using the PIR net-IR signal. The offset computed from the PSP temperatures yields a reliable estimate of the true offset (+/- 1 W/sq m). The offset computed from net-IR is consistent with the true offset at night and under overcast skies but predicts only part of the true range under clear skies.

Determination of the thermal offset of the Eppley precision spectral pyranometer.

PubMed

Haeffelin, M; Kato, S; Smith, A M; Rutledge, C K; Charlock, T P; Mahan, J R

2001-02-01

Eppley's precision spectral pyranometer (PSP) is used in networks around the world to measure downwelling diffuse and global solar irradiance at the surface of the Earth. In recent years several studies have shown significant discrepancy between irradiances measured by pyranometers and those computed by atmospheric radiative transfer models. Pyranometer measurements have been questioned because observed diffuse irradiances sometimes are below theoretical minimum values for a pure molecular atmosphere, and at night the instruments often produce nonzero signals ranging between +5 and -10 W m(-2). We install thermistor sondes in the body of a PSP as well as on its inner dome to monitor the temperature gradients within the instrument, and we operate a pyrgeometer (PIR) instrument side by side with the PSP. We derive a relationship between the PSP output and thermal radiative exchange by the dome and the detector and a relationship between the PSP output and the PIR thermopile output (net-IR). We determine the true PSP offset by quickly capping the instrument at set time intervals. For a ventilated and shaded PSP, the thermal offset can reach -15 W m(-2) under clear skies, whereas it remains close to zero for low overcast clouds. We estimate the PSP thermal offset by two methods: (1) using the PSP temperatures and (2) using the PIR net-IR signal. The offset computed from the PSP temperatures yields a reliable estimate of the true offset (+/-1 W m(-2)). The offset computed from net-IR is consistent with the true offset at night and under overcast skies but predicts only part of the true range under clear skies.

Thermoelectric energy harvesting from diurnal heat flow in the upper soil layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whalen, Scott A.; Dykhuizen, Ronald C.

2012-09-26

We built and tested a subterranean thermoelectric power source that converts diurnal heat flow through the upper soil layer into electricity. This paper describes the operation, design, and performance of the device. Key features of the power source include the use of bismuth-telluride thermopiles optimized for small ΔT and aerogel insulation to minimize thermal losses. The device weighs 0.24 kg and was designed with a flat form factor measuring 12 × 12 × 1.7 cm to facilitate modularity, packing, and assembly into larger arrays. One full year of field testing was performed between June 2009 and May 2010 in Albuquerque,more » New Mexico where the device generated an average power output of 1.1 mW. The season with the highest performance was spring (March–May) while the season of lowest performance was winter (November–January). During May 2010, the device generated an average power of 1.5 mW and a peak power of 9.8 mW at 9.3 V. Ten years of continuous operation at 1.1 mW would yield an energy density and specific energy of 1384 W h/L and 1430 W h/kg respectively, which is competitive with chemical batteries and is orders of magnitude greater than published subterranean and ambient thermoelectric harvesters. Numerical simulations show that performance is sensitive to the thermal properties of the soil and environmental conditions. This class of energy harvester may provide an option for supplemental power, or possibly primary power, for low power remote sensing applications.« less

The origin of the initial heat associated with a single impulse in mammalian non-myelinated nerve fibres

PubMed Central

Howarth, J. V.; Keynes, R. D.; Ritchie, J. M.

1968-01-01

1. A study has been made of the temperature changes associated with the passage of a single impulse in rabbit desheated vagus nerves. 2. The initial changes consist of an evolution of positive heat followed by a reabsorption of most of it; i.e. there is a phase of positive and a phase of negative heat production. 3. The size of the positive heat, its time of onset, and the time of onset of the negative heat have been measured by an analogue method of analysis. In addition, these parameters, together with the size of the negative heat and the duration of both phases of initial heat, have been studied with the aid of a computer, and also by conventional heat block analysis. 4. At about 5° C the measured positive heat is 7·2 μcal/g. impulse. It starts as soon as the compound action potential reaches the thermopile and lasts for about 107 msec. 5. This positive heat decreases with increasing temperature, the ratio of heat at 4° C to that at 14° C being 1·86. 6. The measured negative heat at about 5° C is 4·9 μcal/g. impulse. It starts 102 msec after the onset of positive heat, and lasts for about 240 msec. 7. When the sodium of Locke solution is replaced by lithium the positive heat is reduced by 19%, but the negative heat is increased by 22%. 8. In potassium-free solutions the positive heat is hardly affected (increase of 5%), but the negative heat is more than doubled. As a result the nerve may become briefly colder than its initial temperature by about 2 μ° C. 9. The effect of sodium-deficient solutions on the positive heat is somewhat variable, but the negative heat is consistently diminished. 10. Replacement of the chloride of Locke solution by sulphate or nitrate has little effect on the positive heat. The negative heat is reduced in size by 26% and in duration by 22%. 11. Replacement of most of the sodium of Locke solution by barium reduces or abolishes the negative heat, and increases the measured size of the positive heat nearly threefold. 12. Veratrine (10-5 g/ml.) produces a nearly tenfold increase in the net positive heat. 13. Ouabain (1 mM) and antimycin A (1 μg/ml.) applied for 30-60 min have little effect on the initial heat production. 14. Over the temperature range 5-15° C, and for the ionic solution changes described above, there is close agreement in timing between the positive heat and the rising phase of the action potential, and between the negative heat and the falling phase. 15. Because of the inevitable temporal dispersion of the action potential over the face of the thermopile, the observed temperature changes are smaller than those which occur at a single point in the nerve close to a stimulating electrode. The corrected value of the positive heat at 5° C is 24·5 μcal/g. impulse, while that of the negative heat is 22·2 μcal/g. impulse. 16. The heats of mixing of the ions in solution that interchange during the action potential are much too small to account for the observed initial heats, but an exchange of ions associated with fixed charges might make a significant contribution to the heats. 17. The condenser theory, according to which the positive heat represents the dissipation of electrical energy stored in the membrane capacity, while the negative heat results from the recharging of the capacity, appears unable to account for more than half of the observed temperature changes. 18. It seems probable that the greater part of the initial heat results from changes in the entropy of the nerve membrane when it is depolarized and repolarized. PMID:5636997

Process Analytical Technology in Freeze-Drying: Detection of the Secondary Solute + Water Crystallization with Heat Flux Sensors.

PubMed

Wang, Qiming; Shalaev, Evgenyi

2018-04-01

In situ and non-invasive detection of solute crystallization during freeze-drying would facilitate cycle optimization and scale-up from the laboratory to commercial manufacturing scale. The objective of the study is to evaluate heat flux sensor (HFS) as a tool for monitoring solute crystallization and other first-order phase transitions (e.g., onset of freezing). HFS is a thin-film differential thermopile, which acts as a transducer to generate an electrical signal proportional to the total heat applied to its surface. In this study, HFS is used to detect both primary (ice formation) and secondary (also known as eutectic) solute + water crystallization during cooling and heating of solutions in a freeze-dryer. Binary water-solute mixtures with typical excipients concentrations (e.g., 0.9% of NaCl and 5% mannitol) and fill volumes (1 to 3 ml/vial) are studied. Secondary crystallization is detected by the HFS during cooling in all experiments with NaCl solutions, whereas timing of mannitol crystallization depends on the cooling conditions. In particular, mannitol crystallization takes place during cooling, if the cooling rate is lower than the critical value. On the other hand, if the cooling rate exceeds the critical cooling rate, mannitol crystallization during cooling is prevented, and crystallization occurs during subsequent warming or annealing. It is also observed that, while controlled ice nucleation allows initiation of the primary freezing event in different vials simultaneously, there is a noticeable vial-to-vial difference in the timing of secondary crystallization. The HFS could be a valuable process monitoring tool for non-invasive detection of various crystallization events during freeze-drying manufacturing.

The effects of gamma irradiation on micro-hotplates with integrated temperature sensing diodes

NASA Astrophysics Data System (ADS)

Francis, Laurent A.; André, Nicolas; Boufouss, El Hafed; Gérard, Pierre; Ali, Zeeshan; Udrea, Florin; Flandre, Denis

2014-06-01

Micro-hotplates are MEMS structures of interest for low-power gas sensing, lab-on-chips and space applications, such as micro-thrusters. Micro-hotplates usually consist in a Joule heater suspended on a thin-film membrane while thermopiles or thermodiodes are added as temperature sensors and for feedback control. The implementation of micro-hotplates using a Silicon-On-Insulator technology makes them suited for co-integration with analog integrated circuits and operation at elevated environmental temperatures in a range from 200 to 300 °C, while the heater allows thermal cycling in the kHz regime up to 700 °C, e.g. necessary for the activation of gas sensitive metal-oxide on top of the membrane, with mWrange electrical power. The demonstrated resistance of micro-hotplates to gamma radiations can extend their use in nuclear plants, biomedical sterilization and space applications. In this work, we present results from electrical tests on micro-hotplates during their irradiation by Cobalt-60 gamma rays with total doses up to 18.90 kGy. The micro-hotplates are fabricated using a commercial 1.0 μm Silicon-On-Insulator technology with a tungsten Joule heater, which allows power-controlled operation above 600 °C with less than 60 mW, and temperature sensing silicon diodes located on the membrane and on the bulk. We show the immunity of the sensing platform to the harsh radiation environment. Beside the good tolerance of the thermodiodes and the membrane materials to the total radiation dose, the thermodiode located on the heating membrane is constantly annealed during irradiation and keeps a constant sensitivity while post-irradiation annealing can restore the thermodiode.

Impact of solar ultraviolet radiation on atopic dermatitis symptoms in young children: A longitudinal study.

PubMed

Kim, Young-Min; Kim, Jihyun; Lee, Ji Young; Kim, Minji; Kim, Hyunmi; Jung, Kwon; Eo, Soomi; Ahn, Mijin; Ahn, Kangmo

2017-09-01

There are controversial data about the effects of sun exposure on atopic dermatitis (AD). We evaluated the association between solar ultraviolet radiation (UVR) exposure and AD symptoms in children. Eighty-two children under 6 years (48 boys and 34 girls) with AD living in Seoul, Korea, were enrolled and followed for 12 months between September 2013 and August 2014. Daily symptoms were recorded to describe the degree of itching, sleep disturbance, erythema, dryness, oozing, and edema. We assessed solar UVR by measuring radiation heat flux over the 290-400 nm wavelength range using thermopiles. A generalized linear mixed model and a generalized additive mixed model were used to evaluate the effects of UVR exposure on AD symptoms after adjusting for age, sex, outdoor temperature, outdoor humidity, and ambient air pollution. Symptom records of 12 915 person-days were analyzed. UVR showed a significantly positive relationship with AD symptoms. Over the study period, an increase in UVR by 10 W/cm 2 was associated with a 1.46% increase in AD symptoms (95% CI: 0.85-2.07) on the exposure day. An increase in the 6-day average level of UVR of the previous 5 days and the current day by 10 W/cm 2 was associated with a 3.58% (95% CI: 2.60-4.56) increase in AD symptoms. UVR exposure significantly increased AD symptoms in autumn, but decreased them in winter. Atopic dermatitis symptoms in children are likely to be affected by exposure to solar UVR with a cumulative effect, and this effect is different according to season. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Materials Chemistry Issues in the Development of a Single-Crystal Solar/Thermal Refractive Secondary Concentrator

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Biering, Robert C.

2005-01-01

A translucent crystal concentrates and transmits energy to a heat exchanger, which in turn heats a propellant gas, working gas of a dynamic power system, or a thermopile. Materials are the limiting issue in such a system. Central is the durability of the crystal, which must maintain the required chemical, physical/optical, and mechanical properties as it is heated and cooled. This report summarizes available data to date on the materials issues with this system. We focus on the current leading candidate materials, which are sapphire (Al2O3) for higher temperatures and silica (SiO2) for lower temperatures. We use data from thermochemical calculations; laboratory coupon tests with silica and sapphire; and system tests with sapphire. The required chemical properties include low-vapor pressure and interfacial stability with supporting structural materials. Optical properties such as transmittance and index of refraction must be maintained. Thermomechanical stability is a major challenge for a large, single-crystal ceramic and has been discussed in another report. In addition to the crystal, other materials in the proposed system include refractory metals (Nb, Ta, Mo, W, and Re), carbon (C), and high-temperature ceramic insulation. The major issue here is low levels of oxygen, which lead to volatile refractory metal oxides and rapid consumption of the refractory metal. Interfacial reactions between the ceramic crystal and refractory metal are also discussed. Finally, high-temperature ceramic insulating materials are also likely to be used in this system. Outgassing is a major issue for these materials. The products of outgassing are typically reactive with the refractory metals and must be minimized.

The effect of oxygen enrichment on soot formation and thermal radiation in turbulent, non-premixed methane flames

DOE PAGES

Shaddix, Christopher R.; Williams, Timothy C.

2016-07-12

Non-premixed oxy-fuel combustion of natural gas is used in industrial applications where high-intensity heat is required, such as glass manufacturing and metal forging and shaping. In these applications, the high flame temperatures achieved by oxy-fuel combustion increase radiative heat transfer to the surfaces of interest and soot formation within the flame is desired for further augmentation of radiation. However, the high cost of cryogenic air separation has limited the penetration of oxy-fuel combustion technologies. New approaches to air separation are being developed that may reduce oxygen production costs, but only for intermediate levels of oxygen enrichment of air. To determinemore » the influence of oxygen enrichment on soot formation and radiation, we developed a non-premixed coannular burner in which oxygen concentrations and oxidizer flow rates can be independently varied, to distinguish the effects of turbulent mixing intensity from oxygen enrichment on soot formation and flame radiation. Local radiation intensities, soot concentrations, and soot temperatures have been measured using a thin-film thermopile, planar laser-induced incandescence (LII), and two-color imaging pyrometry, respectively. The measurements show that soot formation increases as the oxygen concentration decreases from 100% to 50%, helping to moderate a decrease in overall flame radiation. An increase in turbulence intensity has a marked effect on flame height, soot formation and thermal radiation, leading to decreases in all of these. The soot temperature decreases with a decrease in the oxygen concentration and increases with an increase in turbulent mixing intensity. Altogether, the results suggest that properly designed oxygen-enriched burners that enhance soot formation for intermediate levels of oxygen purity may be able to achieve thermal radiation intensities as high as 85% of traditional oxy-fuel burners utilizing high-purity oxygen.« less

The effect of oxygen enrichment on soot formation and thermal radiation in turbulent, non-premixed methane flames

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaddix, Christopher R.; Williams, Timothy C.

Non-premixed oxy-fuel combustion of natural gas is used in industrial applications where high-intensity heat is required, such as glass manufacturing and metal forging and shaping. In these applications, the high flame temperatures achieved by oxy-fuel combustion increase radiative heat transfer to the surfaces of interest and soot formation within the flame is desired for further augmentation of radiation. However, the high cost of cryogenic air separation has limited the penetration of oxy-fuel combustion technologies. New approaches to air separation are being developed that may reduce oxygen production costs, but only for intermediate levels of oxygen enrichment of air. To determinemore » the influence of oxygen enrichment on soot formation and radiation, we developed a non-premixed coannular burner in which oxygen concentrations and oxidizer flow rates can be independently varied, to distinguish the effects of turbulent mixing intensity from oxygen enrichment on soot formation and flame radiation. Local radiation intensities, soot concentrations, and soot temperatures have been measured using a thin-film thermopile, planar laser-induced incandescence (LII), and two-color imaging pyrometry, respectively. The measurements show that soot formation increases as the oxygen concentration decreases from 100% to 50%, helping to moderate a decrease in overall flame radiation. An increase in turbulence intensity has a marked effect on flame height, soot formation and thermal radiation, leading to decreases in all of these. The soot temperature decreases with a decrease in the oxygen concentration and increases with an increase in turbulent mixing intensity. Altogether, the results suggest that properly designed oxygen-enriched burners that enhance soot formation for intermediate levels of oxygen purity may be able to achieve thermal radiation intensities as high as 85% of traditional oxy-fuel burners utilizing high-purity oxygen.« less

Crystal Structure of Hyperthermophilic Endo-β-1,4-glucanase

PubMed Central

Zheng, Baisong; Yang, Wen; Zhao, Xinyu; Wang, Yuguo; Lou, Zhiyong; Rao, Zihe; Feng, Yan

2012-01-01

Endo-β-1,4-glucanase from thermophilic Fervidobacterium nodosum Rt17-B1 (FnCel5A), a new member of glycosyl hydrolase family 5, is highly thermostable and exhibits the highest activity on carboxymethylcellulose among the reported homologues. To understand the structural basis for the thermostability and catalytic mechanism, we report here the crystal structures of FnCel5A and the complex with glucose at atomic resolution. FnCel5A exhibited a (β/α)8-barrel structure typical of clan GH-A of the glycoside hydrolase families with a large and deep catalytic pocket located in the C-terminal end of the β-strands that may permit substrate access. A comparison of the structure of FnCel5A with related structures from thermopile Clostridium thermocellum, mesophile Clostridium cellulolyticum, and psychrophile Pseudoalteromonas haloplanktis showed significant differences in intramolecular interactions (salt bridges and hydrogen bonds) that may account for the difference in their thermostabilities. The substrate complex structure in combination with a mutagenesis analysis of the catalytic residues implicates a distinctive catalytic module Glu167-His226-Glu283, which suggests that the histidine may function as an intermediate for the electron transfer network between the typical Glu-Glu catalytic module. Further investigation suggested that the aromatic residues Trp61, Trp204, Phe231, and Trp240 as well as polar residues Asn51, His127, Tyr228, and His235 in the active site not only participated in substrate binding but also provided a unique microenvironment suitable for catalysis. These results provide substantial insight into the unique characteristics of FnCel5A for catalysis and adaptation to extreme temperature. PMID:22128157

MIR-ATR sensor for process monitoring

NASA Astrophysics Data System (ADS)

Geörg, Daniel; Schalk, Robert; Methner, Frank-Jürgen; Beuermann, Thomas

2015-06-01

A mid-infrared attenuated total reflectance (MIR-ATR) sensor has been developed for chemical reaction monitoring. The optical setup of the compact and low-priced sensor consists of an IR emitter as light source, a zinc selenide (ZnSe) ATR prism as boundary to the process, and four thermopile detectors, each equipped with an optical bandpass filter. The practical applicability was tested during esterification of ethanol and formic acid to ethyl formate and water as a model reaction with subsequent distillation. For reference analysis, a Fourier transform mid-infrared (FT-MIR) spectrometer with diamond ATR module was applied. On-line measurements using the MIR-ATR sensor and the FT-MIR spectrometer were performed in a bypass loop. The sensor was calibrated by multiple linear regression in order to link the measured absorbance in the four optical channels to the analyte concentrations. The analytical potential of the MIR-ATR sensor was demonstrated by simultaneous real-time monitoring of all four chemical substances involved in the esterification and distillation process. The temporal courses of the sensor signals are in accordance with the concentration values achieved by the commercial FT-MIR spectrometer. The standard error of prediction for ethanol, formic acid, ethyl formate, and water were 0.38 mol L  -  1, 0.48 mol L  -  1, 0.38 mol L  -  1, and 1.12 mol L  -  1, respectively. A procedure based on MIR spectra is presented to simulate the response characteristics of the sensor if the transmission ranges of the filters are varied. Using this tool analyte specific bandpass filters for a particular chemical reaction can be identified. By exchanging the optical filters, the sensor can be adapted to a wide range of processes in the chemical, pharmaceutical, and beverage industries.

Decadal Variability of Surface Incident Solar Radiation over China

NASA Astrophysics Data System (ADS)

Wang, Kaicun

2015-04-01

Observations have reported a widespread dimming of surface incident solar radiation (Rs) from the 1950s to the 1980s and a brightening afterwards. However, none of the state-of-the-art earth system models, including those from the Coupled Model Intercomparison Project phase 5 (CMIP5), could successfully reproduce the dimming/brightening rates over China. This study provides metadata and reference data to investigate the observed variability of Rs in China. From 1958 to 1990, diffuse solar radiation (Rsdif) and direct solar radiation (Rsdir) was measured separately in China, from which Rs was calculated a sum. However, pyranometers used to measure Rsdif had a strong sensitivity drift problem, which introduced a spurious decreasing trend to Rsdif and Rs measurements. The observed Rsdir did not suffer from such sensitivity drift problem. From 1990 to 1993, the old instruments were replaced and measuring stations were relocated in China, which introduced an abrupt increase in the observed Rs. After 1993, Rs was measured by solid black thermopile pyranometers. Comprehensive comparisons between observation-based and model-based Rs performed in this research have shown that sunshine duration (SunDu)-derived Rs is of high quality and provide accurate estimate of decadal variability of Rs over China. SunDu-derived Rs averaged over 105 stations in China decreased at -2.9 W m-2 per decade from 1961 to 1990 and remained stable afterward. This decadal variability has been confirmed by the observed Rsdir, independent studies on aerosols and diurnal temperature range, and can be reproduced by certain high-quality earth system models. However, neither satellite retrievals (the Global Energy and Water Exchanges Project Surface Radiation Budget (GEWEX SRB)) nor reanalyses (ERA-Interim and Modern-Era Retrospective analysis for Research and Applications (MERRA)) can accurately reproduce such decadal variability of Rs over China for their exclusion of annual variability of tropospheric aerosols.

A low cost mid-infrared sensor for on line contamination monitoring of lubricating oils in marine engines

NASA Astrophysics Data System (ADS)

Ben Mohammadi, L.; Kullmann, F.; Holzki, M.; Sigloch, S.; Klotzbuecher, T.; Spiesen, J.; Tommingas, T.; Weismann, P.; Kimber, G.

2010-04-01

The chemical and physical condition of oils in marine engines must be monitored to ensure optimum performance of the engine and to avoid damage by degraded oil not adequately lubricating the engine. Routine monitoring requires expensive laboratory testing and highly skilled analysts. This work describes the adaptation and implementation of a mid infrared (MIR) sensor module for continued oil condition monitoring in two-stroke and four-stroke diesel engines. The developed sensor module will help to reduce costs in oil analysis by eliminating the need to collect and send samples to a laboratory for analysis. The online MIR-Sensor module measures the contamination of oil with water, soot, as well as the degradation indicated by the TBN (Total Base Number) value. For the analysis of water, TBN, and soot in marine engine oils, four spectral regions of interest have been identified. The optical absorption in these bands correlating with the contaminations is measured simultaneously by using a four-field thermopile detector, combined with appropriate bandpass filters. Recording of the MIR-absorption was performed in a transmission mode using a flow-through cell with appropriate path length. Since in this case no spectrometer is required, the sensor including the light source, the flowthrough- cell, and the detector can be realised at low cost and in a very compact manner. The optical configuration of the sensor with minimal component number and signal intensity optimisation at the four-field detector was implemented by using non-sequential ray tracing simulation. The used calibration model was robust enough to predict accurately the value for soot, water, and TBN concentration for two-stroke and four-stroke engine oils. The sensor device is designed for direct installation on the host engine or machine and, therefore, becoming an integral part of the lubrication system. It can also be used as a portable stand-alone system for machine fluid analysis in the field.

Waveguide infrared spectrometer platform for point and standoff chemical sensing

NASA Astrophysics Data System (ADS)

Chadha, Suneet; Henning, Pat; Landers, Frank; Weling, Ani

2004-03-01

Advanced autonomous detection of chemical warfare agents and toxic industrial chemicals has long been a major military concern. At present, our capability to rapidly assess the immediate environment is severely limited and our domestic infrastructure is burdened by the meticulous procedures required to rule out false threats. While significant advances have recently been accomplished in remote spectral sensing using rugged FTIRs and point detectors, efforts towards low cost chemical discrimination have been lacking. Foster-Miller has developed a unique waveguide spectrometer which is a paradigm shift from the conventional FTIR approach. The spectrometer provides spectral discrimination over the 3-14 μm range and will be the spectrometer platform for both active and passive detection. Foster-Miller has leveraged its innovations in infrared fiber-optic probes and the recent development of a waveguide spectrometer to build a novel infrared sensor platform for both point and stand-off chemical sensing. A monolithic wedge-grating optic provides the spectral dispersion with low cost thermopile point or array detectors picking off the diffracted wavelengths from the optic. The integrated optic provides spectral discrimination between 3-12 μm with resolution at 16 cm-1 or better and overall optical throughput approaching 35%. The device has a fixed cylindrical grating bonded to the edge of a ZnSe conditioning "wedge". The conditioning optic overcomes limitations of concave gratings as it accepts high angle (large FOV) light at the narrow end of the wedge and progressively conditions it to be near normal to the grating. On return, the diffracted wavelengths are concentrated on the discrete or array detector (pixel) elements by the wedge, providing throughput comparable to that of an FTIR. The waveguide spectrometer coupled to ATR probes, flow through liquid cells or multipass gas cells provides significant cost advantage over conventional sampling methodologies. We will present the enabling innovations along with present performance, sensitivity expectations and discrimination algorithm strategy.

Completion of spectral rotating shadowband radiometers and analysis of ARM spectral short-wave data. Technical progress report, November 1, 1994--October 31, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michalsky, J.; Harrison, L.

1995-04-26

The authors goal in the ARM program is the improvement of radiation models used in GCMs, especially in the shortwave, (1) by providing improved shortwave radiometric measurements for the testing of models and (2) by developing methods for retrieving climatologically sensitive parameters that serve as input to shortwave and longwave models. They are acquiring downwelling direct and diffuse spectral irradiance, at six wavelengths, plus downwelling broadband longwave, and upwelling and downwelling broadband shortwave irradiances that they combined with surface and upper air data from the Albany airport as a test data set for ARM modelers. They have also developed algorithmsmore » to improve shortwave measurements made at the Southern Great Plains (SGP) ARM site by standard thermopile instruments and by the multifolter rotating shadowband radiometer (MFRSR). However, the major objective of the program has been the development of two spectral versions of the rotating shadowband radiometer. The MFRSR, has become a workhose at the CART site in Oklahoma and Kansas, and it is widely deployed in other climate programs. They have spent most of their effort this year developing techniques to retrieve column aerosol, water vapor, and ozone from direct beam spectral measurements of the MFRSR. Additionally, they have had success in calculating shortwave surface albedo and aerosol optical depth from the ratio of direct to diffuse spectral irradiance. Using the surface albedo and the global irradiance, they have calculated cloud optical depths. From cloud optical depth and liquid water measured with the microwave radiometer, they have calculated effective liquid cloud particle radii. In each case the authors have attempted to validate the approach using independent measurements or retrievals of the parameters under investigation. With the exception of the ozone intercomparison, the corroborative measurements have been made at the SGP CART site. This report highlights these results.« less

NASA Tech Briefs, June 2014

NASA Technical Reports Server (NTRS)

2014-01-01

Topics include: Real-Time Minimization of Tracking Error for Aircraft Systems; Detecting an Extreme Minority Class in Hyperspectral Data Using Machine Learning; KSC Spaceport Weather Data Archive; Visualizing Acquisition, Processing, and Network Statistics Through Database Queries; Simulating Data Flow via Multiple Secure Connections; Systems and Services for Near-Real-Time Web Access to NPP Data; CCSDS Telemetry Decoder VHDL Core; Thermal Response of a High-Power Switch to Short Pulses; Solar Panel and System Design to Reduce Heating and Optimize Corridors for Lower-Risk Planetary Aerobraking; Low-Cost, Very Large Diamond-Turned Metal Mirror; Very-High-Load-Capacity Air Bearing Spindle for Large Diamond Turning Machines; Elevated-Temperature, Highly Emissive Coating for Energy Dissipation of Large Surfaces; Catalyst for Treatment and Control of Post-Combustion Emissions; Thermally Activated Crack Healing Mechanism for Metallic Materials; Subsurface Imaging of Nanocomposites; Self-Healing Glass Sealants for Solid Oxide Fuel Cells and Electrolyzer Cells; Micromachined Thermopile Arrays with Novel Thermo - electric Materials; Low-Cost, High-Performance MMOD Shielding; Head-Mounted Display Latency Measurement Rig; Workspace-Safe Operation of a Force- or Impedance-Controlled Robot; Cryogenic Mixing Pump with No Moving Parts; Seal Design Feature for Redundancy Verification; Dexterous Humanoid Robot; Tethered Vehicle Control and Tracking System; Lunar Organic Waste Reformer; Digital Laser Frequency Stabilization via Cavity Locking Employing Low-Frequency Direct Modulation; Deep UV Discharge Lamps in Capillary Quartz Tubes with Light Output Coupled to an Optical Fiber; Speech Acquisition and Automatic Speech Recognition for Integrated Spacesuit Audio Systems, Version II; Advanced Sensor Technology for Algal Biotechnology; High-Speed Spectral Mapper; "Ascent - Commemorating Shuttle" - A NASA Film and Multimedia Project DVD; High-Pressure, Reduced-Kinetics Mechanism for N-Hexadecane Oxidation; Method of Error Floor Mitigation in Low-Density Parity-Check Codes; X-Ray Flaw Size Parameter for POD Studies; Large Eddy Simulation Composition Equations for Two-Phase Fully Multicomponent Turbulent Flows; Scheduling Targeted and Mapping Observations with State, Resource, and Timing Constraints;

Radiation Budget Instrument (RBI) for JPSS-2

NASA Technical Reports Server (NTRS)

Georgieva, Elena; Priestley, Kory; Dunn, Barry; Cageao, Richard; Barki, Anum; Osmundsen, Jim; Turczynski, Craig; Abedin, Nurul

2015-01-01

Radiation Budget Instrument (RBI) will be one of five instruments flying aboard the JPSS-2 spacecraft, a polar-orbiting sun-synchronous satellite in Low Earth Orbit. RBI is a passive remote sensing instrument that will follow the successful legacy of the Clouds and Earth's Radiant Energy System (CERES) instruments to make measurement of Earth's short and longwave radiation budget. The goal of RBI is to provide an independent measurement of the broadband reflected solar radiance and Earth's emitted thermal radiance by using three spectral bands (Shortwave, Longwave, and Total) that will have the same overlapped point spread function (PSF) footprint on Earth. To ensure precise NIST-traceable calibration in space the RBI sensor is designed to use a visible calibration target (VCT), a solar calibration target (SCT), and an infrared calibration target (ICT) containing phase change cells (PCC) to enable on-board temperature calibration. The VCT is a thermally controlled integrating sphere with space grade Spectralon covering the inner surface. Two sides of the sphere will have fiber-coupled laser diodes in the UV to IR wavelength region. An electrical substitution radiometer on the integrating sphere will monitor the long term stability of the sources and the possible degradation of the Spectralon in space. In addition the radiometric calibration operations will use the Spectralon diffusers of the SCT to provide accurate measurements of Solar degradation. All those stable on-orbit references will ensure that calibration stability is maintained over the RBI sensor lifetime. For the preflight calibration the RBI will view five calibration sources - two integrating spheres and three CrIS (Cross-track Infrared Sounder ) -like blackbodies whose outputs will be validated with NIST calibration approach. Thermopile are the selected detectors for the RBI. The sensor has a requirement to perform lunar calibration in addition to solar calibration in space in a way similar to CERES instruments approach. To monitor climate change and to get stable and traceable results, it is critical to assure stable calibration over instrument lifetime.

Shortwave Radiometer Calibration Methods Comparison and Resulting Solar Irradiance Measurement Differences: A User Perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habte, Aron; Sengupta, Manajit; Andreas, Afshin

Banks financing solar energy projects require assurance that these systems will produce the energy predicted. Furthermore, utility planners and grid system operators need to understand the impact of the variable solar resource on solar energy conversion system performance. Accurate solar radiation data sets reduce the expense associated with mitigating performance risk and assist in understanding the impacts of solar resource variability. The accuracy of solar radiation measured by radiometers depends on the instrument performance specification, installation method, calibration procedure, measurement conditions, maintenance practices, location, and environmental conditions. This study addresses the effect of different calibration methods provided by radiometric calibrationmore » service providers, such as NREL and manufacturers of radiometers, on the resulting calibration responsivity. Some of these radiometers are calibrated indoors and some outdoors. To establish or understand the differences in calibration methodology, we processed and analyzed field-measured data from these radiometers. This study investigates calibration responsivities provided by NREL's broadband outdoor radiometer calibration (BORCAL) and a few prominent manufacturers. The BORCAL method provides the outdoor calibration responsivity of pyranometers and pyrheliometers at 45 degree solar zenith angle, and as a function of solar zenith angle determined by clear-sky comparisons with reference irradiance. The BORCAL method also employs a thermal offset correction to the calibration responsivity of single-black thermopile detectors used in pyranometers. Indoor calibrations of radiometers by their manufacturers are performed using a stable artificial light source in a side-by-side comparison between the test radiometer under calibration and a reference radiometer of the same type. In both methods, the reference radiometer calibrations are traceable to the World Radiometric Reference (WRR). These different methods of calibration demonstrated +1% to +2% differences in solar irradiance measurement. Analyzing these differences will ultimately help determine the uncertainty of the field radiometer data and guide the development of a consensus standard for calibration. Further advancing procedures for precisely calibrating radiometers to world reference standards that reduce measurement uncertainty will allow more accurate prediction of solar output and improve the bankability of solar projects.« less

A FURTHER EXPERIMENTAL STUDY ON EXCITATION OF INFECTIONS OF THE THROAT

PubMed Central

Grant, Samuel B.; Mudd, Stuart; Goldman, Alfred

1920-01-01

Improvements are described in the method of following temperature changes, and thus alterations in vasomotor tone, in exposed mucous membranes. Invention of an applicator holder, by means of which more sure and stable apposition of the thermopile terminals to the mucous surface may be effected has been the chief advance. Minor improvements have been the use of a saliva ejector and of better calibration technique. The palatine tonsils, like the palate, pharynx, and skin, react to chilling of the body surface with reflex vasoconstriction and ischemia. On rewarming the subject the tonsils quickly more than recover their former blood supply, actually becoming hyperemic; the skin returns to about its control condition; the pharynx and palate remain somewhat ischemic. The hypothesis is advanced that one factor in the beneficial hardening effect of cold bathing and outdoor living, with its incident heightened immunity to respiratory infection, may be the training of the vasomotor system in the direction of development in the pharynx of a reaction of hyperemia following chilling, similar to that observed in the tonsils of the present subjects. With inhalation of amyl nitrite, the skin temperature has always shown a sharp transient rise. The mucous membrane, if relatively ischemic, responds by a rise corresponding to the skin flush. If already hyperemic, local vasodilation in the mucous membrane with amyl nitrite is more than counterbalanced by the lowering of the general blood pressure, and the temperature falls. The flora of the pharynx and tonsils, studied by the unsatisfactory method described, showed, in several instances, after experimentation changes apparently due to proliferation of one of the microorganisms already present. In one case Streptococcus hæmolyticus, in one Micrococcus catarrhalis, and in a third Bacillus influenzæ was the organism showing a relative increase in numbers. The first two instances were associated with sore throat, the third with slight constitutional symptoms. The chilling in the experiments in no instance produced albuminuria or glycosuria, although a more dilute urine was apparently excreted during the experiments. A fall in hydrogen ion concentration, referable to the forced respiration, was noted. PMID:19868432

Antibiotic resistance and biofilm formation of some bacteria isolated from sediment, water and fish farms in Malaysia

NASA Astrophysics Data System (ADS)

Faja, Orooba Meteab; Usup, Gires; Ahmad, Asmat

2018-04-01

A total of 90 isolates of bacteria were isolated, from sediment (10) samples, water (10) samples and fish (12) samples (Sea bass, Snapper, Grouper and Tilapia). These include 22 isolates of bacteria from sediment, 28 isolates from water and 40 isolates from fish. All the isolates were tested for sensitivity to 13 antibiotics using disc diffusion method. The isolates showed high resistance to some antibiotics based on samples source. Isolates from sediment showed highest resistance toward novobiocin, kanamycin, ampicillin and streptomycin while isolates from water showed highest resistance against vancomycin, penicillin, streptomycin and tetracycline, in contrast, in fish sample showed highest resistance toward vancomycin, ampicillin, streptomycin and tetracycline. Most of the isolates showed biofilm formation ability with different degrees. Out of 22 bacteria isolates from water, two isolates were weak biofilm formers, six isolates moderate biofilm formers and fourteen isolates strong biofilm formers. While, out of 28 bacteria isolates from water one isolate was weak biofilm former, five isolates moderate biofilm formers and 22 strong biofilm formers Fish isolate showed three isolates (8%) moderate biofilm formers and 27 isolates strong biofilm formers. Biofilm formation was one of the factors that lead to antibiotic resistance of the bacterial isolates from these samples.

Antimicrobial susceptibility of Escherichia coli isolated from feces of wild cranes migrating to Kagoshima, Japan.

PubMed

Kitadai, Noriyuki; Obi, Takeshi; Yamashita, Shogo; Murase, Toshiyuki; Takase, Kozo

2012-03-01

Susceptibility to 13 antimicrobial agents was examined for 138 Escherichia coli isolates obtained from 192 fecal samples of wild cranes that migrated for wintering to the Izumi plain, Kagoshima prefecture in Japan. The numbers of isolates that were resistant to the antimicrobials used in this study are as follows: oxytetracycline (OTC), 22 isolates; minocycline, 7 isolates; ampicillin (ABPC), 4 isolates; nalidixic acid, 4 isolates; enrofloxacin, 2 isolates; kanamycin, one isolate. Multidrug resistant isolates exhibiting 2-4 drug resistances were obtained. All of the OTC-resistant isolates carried either the tet (A) or tet(B) gene. The bla(TEM) gene was found in all of the ABPC-resistant isolates.

Diversity of proteolytic microbes isolated from Antarctic freshwater lakes and characteristics of their cold-active proteases

NASA Astrophysics Data System (ADS)

Matsui, Mihoko; Kawamata, Akinori; Kosugi, Makiko; Imura, Satoshi; Kurosawa, Norio

2017-09-01

Despite being an extreme environment, the water temperature of freshwater lakes in Antarctica reaches 10 °C in summer, accelerating biological activity. In these environments, proteolytic microbial decomposers may play a large role in protein hydrolysis. We isolated 71 microbial strains showing proteolytic activity at 4 °C from three Antarctic freshwater lakes. They were classified as bacteria (63 isolates) and eukaryotes (8 isolates). The bacterial isolates were classified into the genera Flavobacterium (28 isolates), Pseudomonas (14 isolates), Arthrobacter (10 isolates), Psychrobacter (7 isolates), Cryobacterium (2 isolates), Hymenobacter (1 isolate), and Polaromonas (1 isolate). Five isolates of Flavobacterium and one of Hymenobacter seemed to belong to novel species. All eukaryotic isolates belonged to Glaciozyma antarctica, a psychrophilic yeast species originally isolated from the Weddell Sea near the Joinville Island, Antarctica. A half of representative strains were psychrophilic and did not grow at temperatures above 25 °C. The protease secreted by Pseudomonas prosekii strain ANS4-1 showed the highest activity among all proteases from representative isolates. The results of inhibitor tests indicated that nearly all the isolates secreted metalloproteases. Proteases from four representative isolates retained more than 30% maximal activity at 0 °C. These results expand our knowledge about microbial protein degradation in Antarctic freshwater lakes.

Gradient isolator for flow field of fuel cell assembly

DOEpatents

Ernst, W.D.

1999-06-15

Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions. 4 figs.

Gradient isolator for flow field of fuel cell assembly

DOEpatents

Ernst, William D.

1999-01-01

Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions.

Diversity of halophilic archaea from six hypersaline environments in Turkey.

PubMed

Ozcan, Birgul; Ozcengiz, Gulay; Coleri, Arzu; Cokmus, Cumhur

2007-06-01

The diversity of archaeal strains from six hypersaline environments in Turkey was analyzed by comparing their phenotypic characteristics and 16S rDNA sequences. Thirty-three isolates were characterized in terms of their phenotypic properties including morphological and biochemical characteristics, susceptibility to different antibiotics, and total lipid and plasmid contents, and finally compared by 16S rDNA gene sequences. The results showed that all isolates belong to the family Halobacteriaceae. Phylogenetic analyses using approximately 1,388 bp comparisions of 16S rDNA sequences demonstrated that all isolates clustered closely to species belonging to 9 genera, namely Halorubrum (8 isolates), Natrinema (5 isolates), Haloarcula (4 isolates), Natronococcus (4 isolates), Natrialba (4 isolates), Haloferax (3 isolates), Haloterrigena (3 isolates), Halalkalicoccus (1 isolate), and Halomicrobium (1 isolate). The results revealed a high diversity among the isolated halophilic strains and indicated that some of these strains constitute new taxa of extremely halophilic archaea.

Screening of Different Media and Substrates for Cultural Variability and Mass Culture of Arthrobotrys dactyloides Drechsler

PubMed Central

Kumar, D.; Jaiswal, R. K.

2005-01-01

Variability in growth and sporulation of five isolates of Arthrobotrys dactyloides was studied on five agar, 6 bran and 5 grain media. Potato dextrose agar (PDA) supported maximum growth of isolate A, C and E, while growth of isolate B and D was significantly lower on this medium. On Czapek's agar and yeast glucose agar media the differentiation in the isolates in relation to growth was poor than PDA. The other two media showed much poorer differentiation. On Czapek's agar medium, sporulation was recorded in isolate B only, whereas other isolates showed rare sporulation. Among the bran media, pea bran agar medium supported maximum growth of all the isolates except isolate B. Gram and rice bran agar media were next best. However, the growth of isolate B on the gram bran agar medium was more or less equal as other isolates. On pigeon pea bran agar medium, isolate E failed to grow while other isolates recorded poor growth. On lentil bran agar medium, only isolate B and D recorded little growth, whereas other isolates failed to grow. All the isolates recorded good sporulation on bran agar media except pigeon pea and lentil bran agar media. The grain agar media supported moderate to very good growth of all the isolates. In general isolate B remained slow growing on these media except gram grain and sorghum grain agar media on which growth of this isolate was comparable to other isolates. Sporulation in general, was good on all the grain agar media. Among different substrates screened, barley grain and pea bran were found superior to others for mass culture of isolate A of A. dactyloides. PMID:24049504

Morphological and Genetic Analyses of the Invasive Forest Pathogen Phytophthora austrocedri Reveal that Two Clonal Lineages Colonized Britain and Argentina from a Common Ancestral Population.

PubMed

Henricot, Béatrice; Pérez-Sierra, Ana; Armstrong, April C; Sharp, Paul M; Green, Sarah

2017-12-01

Phytophthora austrocedri is causing widespread mortality of Austrocedrus chilensis in Argentina and Juniperus communis in Britain. The pathogen has also been isolated from J. horizontalis in Germany. Isolates from Britain, Argentina, and Germany are homothallic, with no clear differences in the dimensions of sporangia, oogonia, or oospores. Argentinian and German isolates grew faster than British isolates across a range of media and had a higher temperature tolerance, although most isolates, regardless of origin, grew best at 15°C and all isolates were killed at 25°C. Argentinian and British isolates caused lesions when inoculated onto both A. chilensis and J. communis; however, the Argentinian isolate caused longer lesions on A. chilensis than on J. communis and vice versa for the British isolate. Genetic analyses of nuclear and mitochondrial loci showed that all British isolates are identical. Argentinian isolates and the German isolate are also identical but differ from the British isolates. Single-nucleotide polymorphisms are shared between the British and Argentinian isolates. We concluded that British isolates and Argentinian isolates conform to two distinct clonal lineages of P. austrocedri founded from the same as-yet-unidentified source population. These lineages should be recognized and treated as separate risks by international plant health legislation.

Molecular, ultrastructural, and biological characterization of Pennsylvania isolates of Plum pox virus.

PubMed

Schneider, William L; Damsteegt, Vernon D; Gildow, Fred E; Stone, Andrew L; Sherman, Diana J; Levy, Laurene E; Mavrodieva, Vessela; Richwine, Nancy; Welliver, Ruth; Luster, Douglas G

2011-05-01

Plum pox virus (PPV) was identified in Pennsylvania in 1999. The outbreak was limited to a four-county region in southern Pennsylvania. Initial serological and molecular characterization indicated that the isolates in Pennsylvania belong to the D strain of PPV. The Pennsylvania isolates were characterized by sequence analysis, electron microscopy, host range, and vector transmission to determine how these isolates related to their previously studied European counterparts. Genetically, Pennsylvania (PPV-Penn) isolates were more closely related to each other than to any other PPV-D strains, and isolates from the United States, Canada, and Chile were more closely related to each other than to European isolates. The PPV-Penn isolates exist as two clades, suggesting the possibility of multiple introductions. Electron microscopy analysis of PPV-Penn isolates, including cytopathological studies, indicated that the virions were similar to other Potyvirus spp. PPV-Penn isolates had a herbaceous host range similar to that of European D isolates. There were distinct differences in the transmission efficiencies of the two PPV-Penn isolates using Myzus persicae and Aphis spiraecola as vectors; however, both PPV-Penn isolates were transmitted by M. persicae more efficiently than a European D isolate but less efficiently than a European M isolate.

Mycological survey of Korean cereals and production of mycotoxins by Fusarium isolates.

PubMed Central

Lee, U S; Jang, H S; Tanaka, T; Toyasaki, N; Sugiura, Y; Oh, Y J; Cho, C M; Ueno, Y

1986-01-01

The fungal species isolated from Korean cereals (barley, polished barley, wheat, rye, and malt) were Alternaria spp., Aspergillus spp., Chaetomium spp., Drechslera spp., Epicoccum sp., Fusarium spp., and Penicillium spp., etc. The number of Fusarium strains isolated was 36, and their ability to produce Fusarium mycotoxins on rice was tested. Nivalenol (NIV) was produced by Fusarium graminearum (7 of 9 isolates), Fusarium oxysporum (3 of 10 isolates), and Fusarium spp. (7 of 15 isolates). Of 15 isolates of Fusarium spp., 6 formed deoxynivalenol (DON). Fusarenon-X and 3-acetyl-DON were produced by most NIV- and DON-forming isolates, respectively. Zearalenone was produced by 3 isolates of F. graminearum, 1 isolate of Fusarium equiseti, and 11 isolates of Fusarium spp. T-2 toxin was not produced by any Fusarium isolates. The highest concentrations of mycotoxins produced by Fusarium isolates were 77.4 (NIV), 5.3 (DON), 138.3 (fusarenon-X), 40.6 (3-acetyl-DON), and 23.2 (zearalenone) micrograms/g. PMID:2947538

Mycological survey of Korean cereals and production of mycotoxins by Fusarium isolates.

PubMed

Lee, U S; Jang, H S; Tanaka, T; Toyasaki, N; Sugiura, Y; Oh, Y J; Cho, C M; Ueno, Y

1986-12-01

The fungal species isolated from Korean cereals (barley, polished barley, wheat, rye, and malt) were Alternaria spp., Aspergillus spp., Chaetomium spp., Drechslera spp., Epicoccum sp., Fusarium spp., and Penicillium spp., etc. The number of Fusarium strains isolated was 36, and their ability to produce Fusarium mycotoxins on rice was tested. Nivalenol (NIV) was produced by Fusarium graminearum (7 of 9 isolates), Fusarium oxysporum (3 of 10 isolates), and Fusarium spp. (7 of 15 isolates). Of 15 isolates of Fusarium spp., 6 formed deoxynivalenol (DON). Fusarenon-X and 3-acetyl-DON were produced by most NIV- and DON-forming isolates, respectively. Zearalenone was produced by 3 isolates of F. graminearum, 1 isolate of Fusarium equiseti, and 11 isolates of Fusarium spp. T-2 toxin was not produced by any Fusarium isolates. The highest concentrations of mycotoxins produced by Fusarium isolates were 77.4 (NIV), 5.3 (DON), 138.3 (fusarenon-X), 40.6 (3-acetyl-DON), and 23.2 (zearalenone) micrograms/g.

Phylogenetic Diversity of Vibrio cholerae Associated with Endemic Cholera in Mexico from 1991 to 2008

PubMed Central

Choi, Seon Young; Rashed, Shah M.; Hasan, Nur A.; Alam, Munirul; Islam, Tarequl; Sadique, Abdus; Johura, Fatema-Tuz; Eppinger, Mark; Huq, Anwar; Cravioto, Alejandro

2016-01-01

ABSTRACT An outbreak of cholera occurred in 1991 in Mexico, where it had not been reported for more than a century and is now endemic. Vibrio cholerae O1 prototype El Tor and classical strains coexist with altered El Tor strains (1991 to 1997). Nontoxigenic (CTX−) V. cholerae El Tor dominated toxigenic (CTX+) strains (2001 to 2003), but V. cholerae CTX+ variant El Tor was isolated during 2004 to 2008, outcompeting CTX− V. cholerae. Genomes of six Mexican V. cholerae O1 strains isolated during 1991 to 2008 were sequenced and compared with both contemporary and archived strains of V. cholerae. Three were CTX+ El Tor, two were CTX− El Tor, and the remaining strain was a CTX+ classical isolate. Whole-genome sequence analysis showed the six isolates belonged to five distinct phylogenetic clades. One CTX− isolate is ancestral to the 6th and 7th pandemic CTX+ V. cholerae isolates. The other CTX− isolate joined with CTX− non-O1/O139 isolates from Haiti and seroconverted O1 isolates from Brazil and Amazonia. One CTX+ isolate was phylogenetically placed with the sixth pandemic classical clade and the V. cholerae O395 classical reference strain. Two CTX+ El Tor isolates possessing intact Vibrio seventh pandemic island II (VSP-II) are related to hybrid El Tor isolates from Mozambique and Bangladesh. The third CTX+ El Tor isolate contained West African-South American (WASA) recombination in VSP-II and showed relatedness to isolates from Peru and Brazil. Except for one isolate, all Mexican isolates lack SXT/R391 integrative conjugative elements (ICEs) and sensitivity to selected antibiotics, with one isolate resistant to streptomycin. No isolates were related to contemporary isolates from Asia, Africa, or Haiti, indicating phylogenetic diversity. PMID:26980836

Design and optimization of voice coil actuator for six degree of freedom active vibration isolation system using Halbach magnet array.

PubMed

Kim, MyeongHyeon; Kim, Hyunchang; Gweon, Dae-Gab

2012-10-01

This paper describes the design, modeling, optimization, and validation of an active vibration isolation system using a voice coil motor. The active vibration isolating method was constructed with a passive isolator and an active isolator. A spring was used for passive isolating; an actuator was used for active isolating. The proposed active vibration isolation system (AVIS) can isolate disturbances for many kinds of instruments. Until now, developed AVIS were able to isolate a six degree-of-freedom disturbance effectively. This paper proposes the realization of such a six degree-of-freedom active vibration isolation system that can work as a bench top device for precision measuring machines such as atomic force microscope, scanning probe microscope, etc.

Typing and Subtyping of 83 Clinical Isolates Purified from Surgically Implanted Silicone Feeding Tubes by Random Amplified Polymorphic DNA Amplification

PubMed Central

Dautle, Melanie P.; Ulrich, Ricky L.; Hughes, Thomas A.

2002-01-01

In this study, 83 clinical isolates purified from biofilms colonizing 18 silicone gastrostomy devices (12 “buttons” and six tubes converted to skin level devices) were selected for subtype characterization utilizing genetic analysis. The tubes, previously used for feeding, remained in place for 3 to 47 months (mean, 20.0 months) in children ranging in age from 6 months to 17 years. Classification of specific microbes using random amplified polymorphic DNA (RAPD) analysis revealed genetic similarities and differences among isolates belonging to the same genus. Both gram-positive and -negative bacteria were investigated, including 2 isolates of Bacillus brevis, 4 isolates of Bacillus licheniformis, 2 isolates of Bacillus pumilus, 3 isolates of Enterococcus durans, 19 isolates of Enterococcus faecalis, 8 isolates of Enterococcus faecium, 2 isolates of Enterococcus hirae, 7 isolates of Escherichia coli, 8 isolates of Lactobacillus plantarum, 19 isolates of Staphylococcus aureus, 2 isolates of Staphylococcus epidermidis, and 7 isolates of Staphylococcus saprophyticus. Amplified DNA fragments (amplicons) provided species-specific fingerprints for comparison by agarose gel electrophoresis. A total of 62 distinct RAPD types were categorized from the five genera studied. Typing analysis suggested cross acquisition of E. coli, E. faecalis, and S. aureus in three patient pairs. Genomic polymorphism detection proved efficient and reliable for classifying bacterial subtypes isolated from biofilms adhering to various portions of commonly employed enteral access tubes. PMID:11825951

Genetic diversity of Mycobacterium tuberculosis isolates from Tochigi prefecture, a local region of Japan.

PubMed

Mizukoshi, Fuminori; Miyoshi-Akiyama, Tohru; Iwai, Hiroki; Suzuki, Takako; Kiritani, Reiko; Kirikae, Teruo; Funatogawa, Keiji

2017-05-25

Foreign-born patients with tuberculosis (TB) may introduce globally disseminated isolates of Mycobacterium tuberculosis into large cities in Japan. The risk of dissemination of these isolates into local regions, however, has not been determined. This study analyzed the molecular epidemiology of M. tuberculosis isolates obtained from TB patients living in a local region of Japan. Whole genome sequences of 169 M. tuberculosis isolates, obtained from 148 Japanese-born and 21 foreign-born patients living in Tochigi, Japan, were analyzed using the Comprehensive analysis server for the Mycobacterium t u b erculosis complex (CASTB). The 169 isolates were clustered into four clades; Lineage 2 (111 isolates 65.7%), Lineage 4 (43 isolates, 25.4%), Lineage 1 (13 isolates, 7.7%), and Lineage 3 (2 isolates, 1.2%). Of the 111 isolates belonging to Lineage 2, 79 (71.2%) were of the atypical Beijing sub-genotype. Of the 13 Lineage 1 isolates, nine (69.2%) were from foreign-born patients. The isolates belonging to Lineage 4 were further clustered into three clades, two containing isolates shared by both Japanese- and foreign-born patients. The two isolates belonging to Lineage 3 were obtained from foreign-born patients. The genotypic diversity of M. tuberculosis in a local region of Japan is increased primarily by the presence of isolates obtained from foreign-born patients.

First report of extended-spectrum β-lactamases among clinical isolates of Escherichia coli in Gaza Strip, Palestine.

PubMed

Tayh, Ghassan; Ben Sallem, Rym; Ben Yahia, Houssem; Gharsa, Haythem; Klibi, Naouel; Boudabous, Abdellatif; Ben Slama, Karim

2016-09-01

This study aimed to assess the occurrence of extended-spectrum β-lactamases (ESBLs) in clinical Escherichia coli isolates from Palestine and to characterise their type, genetic environments and associated resistance genes. Twenty-seven broad-spectrum-cephalosporin-resistant E. coli isolates were recovered between April and June 2013 in Gaza Strip hospitals. Characterisation of ESBL genes and their genetic environments, detection of associated resistance genes, and the presence and characterisation of integrons were performed by PCR and sequencing. The clonal relationship among ESBL-positive E. coli strains was determined by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme XbaI. Phylogroup typing and virulence factors were studied by PCR. The following ESBL genes were identified: blaCTX-M-15 (21 isolates); blaCTX-M-14a (2 isolates); blaCTX-M-1 (2 isolates); blaCTX-M-3 (1 isolate); and blaCTX-M-27 (1 isolate). The blaTEM-1 gene was also detected in eight CTX-M-producing strains. The ISEcp1 sequence was found upstream of blaCTX-M in 23 isolates, and orf477 was found downstream of this gene in 24 isolates. IS903 was also detected downstream in three isolates. Six isolates carried class 1 integrons with the gene cassette arrangement dfrA17-aadA5. High clonal diversity was observed among the studied isolates by PFGE (24 unrelated profiles). The virulence gene fimA was detected in 23 isolates, the aer gene in 8 isolates and the papC gene in 7 isolates. The studied isolates belonged to phylogroups B2 (12 isolates), D (12 isolates) and A (3 isolates). This is the first report of the detection of CTX-M class β-lactamases in E. coli of clinical origin in Gaza Strip hospitals. Copyright © 2016 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

Similarities between Salmonella Enteritidis isolated from humans and captive wild animals in South Africa.

PubMed

Smith, Anthony M; Ismail, Husna; Henton, Maryke M; Keddy, Karen H

2014-12-15

Salmonella is well recognized as an aetiological agent of gastrointestinal and diarrhoeal disease. Salmonella enterica serotype Enteritidis (Salmonella Enteritidis) is one of the commonest serotypes associated with foodborne illness. In South Africa, we compared Salmonella Enteritidis strains isolated from humans with gastroenteritis and strains isolated from captive wild animals, between June 2011 and July 2012. Bacteria were phenotypically characterized using standard microbiological techniques. Genotypic relatedness of isolates was investigated by pulsed-field gel electrophoresis (PFGE) analysis. a diversity of 27 PFGE patterns amongst 196 human non-invasive isolates was shown; two PFGE patterns predominated and accounted for 74% of all human isolates. Human isolates showed a 12% prevalence rate for nalidixic acid resistance. Animal isolates from 5 different sources were investigated. With the exception of an isolate from a ground hornbill, all animal isolates (jaguar, crocodile, lion and poultry) showed PFGE pattern matches to a human isolate. Animal isolates showed susceptibility to all antimicrobial agents tested, with the exception of nalidixic acid resistance in isolates from the lion and poultry source. Our data showed similarities between Salmonella Enteritidis strains isolated from humans and captive wild animals, suggesting a probable common source for strains from humans and animals.

Isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in laboratory settings.

PubMed

Qudratullah; Muhammad, G; Saqib, M; Bilal, M Qamar

2017-08-01

The present study was designed to investigate isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in rabbits and mice. Isolates of P. multocida, S. aureus and Str. agalactiae recovered from field cases of Hemorragic septicemia and mastitis were scrutinized for virulence/pathogenicity and immunogenicity. Mouse LD 50 of P. multocida showed that P. multocida isolate No.1 was more virulent than isolates No. 2 and 3. Virulence of isolate No.1S. aureus and Str. agalactiae revealed that 100, 80% rabbits died within 18h of inoculation. Seven-digit numerical profiles of these 4 isolates with API ® Staph test strips isolates, No.1 (6736153) showed good identification (S. aureus id=90.3%). Indirect ELISA-based serum antibody titers to P. multocida isolate No.1, S. aureus No.1, Str. agalactiae, isolate No.1 elicited high antibody titers 1.9, 1.23, 1.12 respectively. All the pathogens of Isolate No. 1 (P. multocida, S. aureus Str. agalactiae), were high antibody than others isolates. Copyright © 2017 Elsevier B.V. All rights reserved.

Nucleotide sequences of Japanese isolates of citrus vein enation virus.

PubMed

Nakazono-Nagaoka, Eiko; Fujikawa, Takashi; Iwanami, Toru

2017-03-01

The genomic sequences of five Japanese isolates of citrus vein enation virus (CVEV) isolates that induce vein enation were determined and compared with that of the Spanish isolate VE-1. The nucleotide sequences of all Japanese isolates were 5,983 nt in length. The genomic RNA of Japanese isolates had five potential open reading frames (ORF 0, ORF 1, ORF 2, ORF 3, and ORF 5) in the positive-sense strand. The nucleotide sequence identity among the Japanese isolates and Spanish isolate VE-1 ranged from 98.0% to 99.8%. Comparison of the partial amino acid sequences of ten Japanese isolates and three Spanish isolates suggested that four amino acid residues, at positions of 83, 104, and 113 in ORF 2 and position 41 in ORF 5, might be unique to some Japanese isolates.

Clonal Spread of Levofloxacin-Resistant Streptococcus pneumoniae Invasive Isolates in Madrid, Spain, 2007 to 2009▿

PubMed Central

Rodríguez-Avial, Iciar; Ramos, Belén; Ríos, Esther; Cercenado, Emilia; Ordobás, María; Sanz, Juan Carlos

2011-01-01

Among 1,349 Streptococcus pneumoniae invasive isolates, 45 (3.3%) were levofloxacin resistant. Serotype distribution was as follows: 8 (n = 32 isolates), 19A (n = 4 isolates), 7F (n = 3 isolates), 9V (n = 2 isolates), 10A (n = 1 isolate), 19F (n = 1 isolate), 6B (n = 1 isolate), and nontypeable (n = 1 isolate). Levofloxacin-resistant isolates had dual mutations in the gyrA and parC genes. Serotype 8 strains corresponded to a capsular switching of the Sweden15A-25 clone. Levofloxacin resistance was also detected among multiresistant (ST27619A, Spain9V-ST156, ST8819F, and ST15426B) and among usually antibiotic-susceptible (Netherlands7F-ST191, ST120119A, and ST263910A) clones. PMID:21383091

Brazilian kefir: structure, microbial communities and chemical composition.

PubMed

Magalhães, Karina Teixeira; de Melo Pereira, Gilberto Vinícius; Campos, Cássia Roberta; Dragone, Giuliano; Schwan, Rosane Freitas

2011-04-01

Microbial ecology and chemical composition of Brazilian kefir beverage was performed. The microorganisms associated with Brazilian kefir were investigated using a combination of phenotypic and genotypic methods. A total of 359 microbial isolates were identified. Lactic acid bacteria (60.5%) were the major isolated group identified, followed by yeasts (30.6%) and acetic acid bacteria (8.9%). Lactobacillus paracasei (89 isolates), Lactobacillus parabuchneri (41 isolates), Lactobacillus casei (32 isolates), Lactobacillus kefiri (31 isolates), Lactococcus lactis (24 isolates), Acetobacter lovaniensis (32 isolates), Kluyveromyces lactis (31 isolates), Kazachstania aerobia (23 isolates), Saccharomyces cerevisiae (41 isolates) and Lachancea meyersii (15 isolates) were the microbial species isolated. Scanning electron microscopy showed that the microbiota was dominated by bacilli (short and curved long) cells growing in close association with lemon-shaped yeasts cells. During the 24 h of fermentation, the protein content increased, while lactose and fat content decreased. The concentration of lactic acid ranged from 1.4 to 17.4 mg/ml, and that of acetic acid increased from 2.1 to 2.73 mg/ml. The production of ethanol was limited, reaching a final mean value of 0.5 mg/ml.

Brazilian kefir: structure, microbial communities and chemical composition

PubMed Central

Magalhães, Karina Teixeira; de Melo Pereira, Gilberto Vinícius; Campos, Cássia Roberta; Dragone, Giuliano; Schwan, Rosane Freitas

2011-01-01

Microbial ecology and chemical composition of Brazilian kefir beverage was performed. The microorganisms associated with Brazilian kefir were investigated using a combination of phenotypic and genotypic methods. A total of 359 microbial isolates were identified. Lactic acid bacteria (60.5%) were the major isolated group identified, followed by yeasts (30.6%) and acetic acid bacteria (8.9%). Lactobacillus paracasei (89 isolates), Lactobacillus parabuchneri (41 isolates), Lactobacillus casei (32 isolates), Lactobacillus kefiri (31 isolates), Lactococcus lactis (24 isolates), Acetobacter lovaniensis (32 isolates), Kluyveromyces lactis (31 isolates), Kazachstania aerobia (23 isolates), Saccharomyces cerevisiae (41 isolates) and Lachancea meyersii (15 isolates) were the microbial species isolated. Scanning electron microscopy showed that the microbiota was dominated by bacilli (short and curved long) cells growing in close association with lemon-shaped yeasts cells. During the 24 h of fermentation, the protein content increased, while lactose and fat content decreased. The concentration of lactic acid ranged from 1.4 to 17.4 mg/ml, and that of acetic acid increased from 2.1 to 2.73 mg/ml. The production of ethanol was limited, reaching a final mean value of 0.5 mg/ml. PMID:24031681

Genetic relatedness of a rarely isolated Salmonella: Salmonella enterica serotype Niakhar from NARMS animal isolates.

PubMed

Tankson, J D; Fedorka-Cray, P J; Jackson, C R; Headrick, M

2006-02-01

In the United States, Salmonella enterica serotype Niakhar is infrequently isolated. Between 1997 and 2000, the animal arm of the National Antimicrobial Resistance Monitoring System-Enteric Bacteria (NARMS) assayed a total of 22,383 Salmonella isolates from various animal sources (swine, cattle, chickens, turkeys, cats, horses, exotics and dogs) for antimicrobial susceptibility. Isolates originated from diagnostic and non-diagnostic submissions. To study the phenotypic and genotypic characteristics of Salmonella Niakhar. Only five (0.02%) of the 22,383 isolates were identified as Salmonella Niakhar. Antimicrobial resistance testing indicated that three isolates were pan-susceptible, one isolate was resistant to ampicillin and one isolate was resistant to ampicillin, chloramphenicol, ciprofloxacin, kanamycin, nalidixic acid, streptomycin, sulfamethoxazole, tetracycline and trimethoprim/sulfamethoxazole. RAPD-PCR analysis, PFGE and ribotyping indicated that two pan-susceptible isolates were genetically similar, whereas the three remaining isolates were genetically different. The one Salmonella Niakhar isolate that was multiresistant harboured a class I integron, intI1 and two large plasmids. This study represents the first report of a ciprofloxacin-resistant Salmonella isolate from the animal arm of NARMS.

Characterization of Staphylococcus aureus Isolated from Food Products in Western Algeria.

PubMed

Chaalal, Wafaa; Chaalal, Nadia; Bourafa, Nadjette; Kihal, Mebrouk; Diene, Seydina M; Rolain, Jean-Marc

2018-03-15

The current study aimed to characterize Staphylococcus aureus isolates from foodstuffs collected from western Algeria. A total of 153 S. aureus isolates from various raw and processed foods were obtained and identified using matrix-assisted laser desorption and ionization time-of-flight mass spectrometry. Isolates were characterized by antimicrobial susceptibility testing and toxin gene detection. Methicillin-resistant Staphylococcus aureus (MRSA) isolates were identified by detection of the mecA gene and characterized by staphylococcal cassette chromosome mec (SCCmec) typing. We found that 30.9% (153/495) of food samples were contaminated with S. aureus. Thirty-three (21.5%) S. aureus isolates were identified as MRSA, and 16.9% (26/153) carried the mecA gene. Three SCCmec types were identified of which type IV was the most common (69.2%) followed by type V (15.3%) and type II (7.6%). Two MRSA isolates were not typable with SCCmec typing. None of the examined isolates harbored mecC. Furthermore, 14.3% (22/153) of the isolates were toxigenic S. aureus. The cytotoxin gene pvl was detected in 11.1% of the S. aureus isolates. This gene was more commonly detected (76.4%) in MRSA isolates than in methicillin-suceptible Staphylococcus aureus (MSSA) isolates. The tsst-1 gene coding for toxic shock syndrome toxin was isolated rarely (3.2%) and only in MSSA isolates. According to disk diffusion test results, 70 isolates were resistant to only one antimicrobial drug, and 51 (33.3%) isolates were multidrug resistant. Other 32 isolates were susceptible to all antibiotics. Our study highlights, for the first time, a high prevalence of multidrug-resistant S. aureus isolates carrying pvl or tsst-1 found in food products in Algeria. The risk of MRSA transmission through the food chain cannot be disregarded, particularly in uncooked foods.

Antibiotic resistance and virulence traits in clinical and environmental Enterococcus faecalis and Enterococcus faecium isolates.

PubMed

Rathnayake, I U; Hargreaves, M; Huygens, F

2012-07-01

This study compared virulence and antibiotic resistance traits in clinical and environmental Enterococcus faecalis and Enterococcus faecium isolates. E. faecalis isolates harboured a broader spectrum of virulence determinants compared to E. faecium isolates. The virulence traits Cyl-A, Cyl-B, Cyl-M, gel-E, esp and acm were tested and environmental isolates predominantly harboured gel-E (80% of E. faecalis and 31.9% of E. faecium) whereas esp was more prevalent in clinical isolates (67.8% of E. faecalis and 70.4% of E. faecium). E. faecalis and E. faecium isolated from water had different antibiotic resistance patterns compared to those isolated from clinical samples. Linezolid resistance was not observed in any isolates tested and vancomycin resistance was observed only in clinical isolates. Resistance to other antibiotics (tetracycline, gentamicin, ciprofloxacin and ampicillin) was detected in both clinical and water isolates. Clinical isolates were more resistant to all the antibiotics tested compared to water isolates. Multi-drug resistance was more prevalent in clinical isolates (71.2% of E. faecalis and 70.3% of E. faecium) compared to water isolates (only 5.7% E. faecium). tet L and tet M genes were predominantly identified in tetracycline-resistant isolates. All water and clinical isolates resistant to ciprofloxacin and ampicillin contained mutations in the gyrA, parC and pbp5 genes. A significant correlation was found between the presence of virulence determinants and antibiotic resistance in all the isolates tested in this study (p<0.05). The presence of antibiotic resistant enterococci, together with associated virulence traits, in surface recreational water could be a public health risk. Copyright © 2012 Elsevier GmbH. All rights reserved.

A standard bacterial isolate set for research on contemporary dairy spoilage.

PubMed

Trmčić, A; Martin, N H; Boor, K J; Wiedmann, M

2015-08-01

Food spoilage is an ongoing issue that could be dealt with more efficiently if some standardization and unification was introduced in this field of research. For example, research and development efforts to understand and reduce food spoilage can greatly be enhanced through availability and use of standardized isolate sets. To address this critical issue, we have assembled a standard isolate set of dairy spoilers and other selected nonpathogenic organisms frequently associated with dairy products. This publicly available bacterial set consists of (1) 35 gram-positive isolates including 9 Bacillus and 15 Paenibacillus isolates and (2) 16 gram-negative isolates including 4 Pseudomonas and 8 coliform isolates. The set includes isolates obtained from samples of pasteurized milk (n=43), pasteurized chocolate milk (n=1), raw milk (n=1), cheese (n=2), as well as isolates obtained from samples obtained from dairy-powder production (n=4). Analysis of growth characteristics in skim milk broth identified 16 gram-positive and 13 gram-negative isolates as psychrotolerant. Additional phenotypic characterization of isolates included testing for activity of β-galactosidase and lipolytic and proteolytic enzymes. All groups of isolates included in the isolate set exhibited diversity in growth and enzyme activity. Source data for all isolates in this isolate set are publicly available in the FoodMicrobeTracker database (http://www.foodmicrobetracker.com), which allows for continuous updating of information and advancement of knowledge on dairy-spoilage representatives included in this isolate set. This isolate set along with publicly available isolate data provide a unique resource that will help advance knowledge of dairy-spoilage organisms as well as aid industry in development and validation of new control strategies. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

In Vitro Activities of Faropenem against 579 Strains of Anaerobic Bacteria

PubMed Central

Wexler, Hannah M.; Molitoris, Denise; St. John, Shahera; Vu, Ann; Read, Erik K.; Finegold, Sydney M.

2002-01-01

The activity of faropenem, a new oral penem, was tested against 579 strains of anaerobic bacteria by using the NCCLS-approved reference method. Drugs tested included amoxicillin-clavulanate, cefoxitin, clindamycin, faropenem, imipenem, and metronidazole. Of the 176 strains of Bacteroides fragilis group isolates tested, two isolates had faropenem MICs of 64 μg/ml and imipenem MICs of >32 μg/ml. Faropenem had an MIC of 16 μg/ml for an additional isolate of B. fragilis; this strain was sensitive to imipenem (MIC of 1 μg/ml). Both faropenem and imipenem had MICs of ≤4 μg/ml for all isolates of Bacteroides capillosus (10 isolates), Bacteroides splanchnicus (13 isolates), Bacteroides ureolyticus (11 isolates), Bilophila wadsworthia (11 isolates), Porphyromonas species (42 isolates), Prevotella species (78 isolates), Campylobacter species (25 isolates), Sutterella wadsworthensis (11 isolates), Fusobacterium nucleatum (19 isolates), Fusobacterium mortiferum/varium (20 isolates), and other Fusobacterium species (9 isolates). Faropenem and imipenem had MICs of 16 to 32 μg/ml for two strains of Clostridium difficile; the MICs for all other strains of Clostridium tested (69 isolates) were ≤4 μg/ml. Faropenem had MICs of 8 and 16 μg/ml, respectively, for two strains of Peptostreptococcus anaerobius (MICs of imipenem were 2 μg/ml). MICs were ≤4 μg/ml for all other strains of gram-positive anaerobic cocci (53 isolates) and non-spore-forming gram-positive rods (28 isolates). Other results were as expected and reported in previous studies. No metronidazole resistance was seen in gram-negative anaerobes other than S. wadsworthensis (18% resistant); 63% of gram-positive non-spore-forming rods were resistant. Some degree of clindamycin resistance was seen in most of the groups tested. PMID:12384389

Isolation and Identification of Active Compounds from Papaya Plants and Activities as Antimicrobial

NASA Astrophysics Data System (ADS)

Prasetya, A. T.; Mursiti, S.; Maryan, S.; Jati, N. K.

2018-04-01

Extraction and isolation of papaya seeds and leaves (Carica papaya L) has been performed using n-hexane and ethanol solvents. Further isolation of the extract obtained using ethyl acetate and diethyl ether solvents. The result of the phytochemical test of papaya extract obtained by mixture of an active compound of flavonoids, alkaloids, tannins, steroids, and saponins. Ethyl acetate isolates containing only flavonoids and diethyl ether isolates contain only alkaloids. Extracts and isolates from papaya plants had gram-positive antibacterial activity greater than the gram-negative bacteria, but both did not have antifungal activity. Papaya extracts have greater antibacterial activity than flavonoid isolates and alkaloid isolates. Strong antibacterial inhibitory sequences are extracts of papaya plants, flavonoid isolates, and alkaloid isolates.

Fitness and Competitive Ability of Botrytis cinerea Isolates with Resistance to Multiple Chemical Classes of Fungicides.

PubMed

Chen, S N; Luo, C X; Hu, M J; Schnabel, G

2016-09-01

Resistance to multiple chemical classes of fungicides in Botrytis cinerea isolates from eastern United States strawberry fields is common and strategies to control them are needed. In this study, we compared fitness and competitive ability of eight sensitive isolates (S), eight isolates resistant to five or six chemical classes of fungicides but not to phenylpyrroles (5CCR), and eight isolates resistant to six or seven chemical classes including phenylpyrroles (6CCR/MDR1h). The latter included the MDR1h phenotype due to overexpression of atrB based on Δ497V/L in mrr1. The 6CCR/MDR1h isolates grew more slowly at 4°C on potato dextrose agar, and both 5CCR and 6CCR/MDR1h isolates were hypersensitive to osmotic stress compared with S isolates. In contrast, no differences were found in oxidative sensitivity, aggressiveness, and spore production in vivo, and sclerotia production and viability in vitro. In competition experiments, the 5CCR and 6CCR/MDR1h isolates were both outcompeted by S isolates and 6CCR/MDR1h isolates were outcompeted by 5CCR isolates in the absence of fungicide pressure. Under selective pressure of a fludioxonil/pyraclostrobin rotation, the 6CCR/MDR1h isolates dominated after coinoculation with 5CCR and S isolates. The competitive disadvantage of 5CCR and especially 6CCR/MDR1h isolates suggest that, in the absence of fungicide selection pressure, S isolates may reduce inoculum potential of multifungicide-resistant isolates under field conditions.

Pasteurella multocida isolated from wild birds of North America: a serotype and DNA fingerprint study of isolates from 1978 to 1993

USGS Publications Warehouse

Wilson, M.A.; Duncan, R.M.; Nordholm, G.E.; Berlowski, B.M.

1995-01-01

Serotype and DNA fingerprint methods were used to study Pasteurella multocida isolated from 320 wild birds of North America. Isolates were collected during 1978-93. The HhaI profiles of 314 isolates matched the HhaI profile of somatic reference type 1, strain X-73; somatic type 1 antigen was expressed by 310 isolates, and the serotype of four isolates was undetected. Differentiation of the 314 isolates was observed by digestion of DNA with HpaII. None of the HpaII profiles matched the HpaII profile of X-73 (designated HhaI 001/HpaII 001). Three HpaII profiles were recognized among the somatic type 1 isolates: HpaII 002 (n = 18), HpaII 003 (n = 122), and HpaII 004 (n = 174). Profile HpaII 002 was found among isolates collected during 1979-83. Profile HpaII 003 was identified from isolates collected during 1979-89, with the exception of two isolates in 1992. The HpaII 004 profile was identified from isolates collected during 1983-93. Of the six remaining isolates, four expressed somatic type 4 and had HhaI profiles identical to the somatic type 4 reference strain P-1662 profile (designated HhaI 004); these isolates were differentiated by digestion of DNA with HpaII. One isolate was identified as serotype F:11, and another was serotype A:3,4. In the present study, 314 of 316 (99.4%) isolates from wild birds in the Central, Mississippi, and Pacific flyways during 1978-93, were P. multocida somatic type 1.

Occurrence of Diverse AbGRI1-Type Genomic Islands in Acinetobacter baumannii Global Clone 2 Isolates from South Korea.

PubMed

Kim, Dae Hun; Jung, Sook-In; Kwon, Ki Tae; Ko, Kwan Soo

2017-02-01

In this study, we analyzed the frequency of the AbGRI1-type genomic island (GI) and its association with genotypes. We obtained 130 Acinetobacter baumannii isolates causing bloodstream infections from patients in South Korea. Antimicrobial susceptibility testing and multilocus sequence typing were performed. The presence of AbGRI1-type GIs and their structures were determined by sequential PCR and sequencing. Ninety-eight isolates (75.3%) representing 14 sequence types (STs) belonged to clonal complex 208 (CC208), corresponding to global clone 2 (GC2). AbGRI1-type GIs interrupted the comM gene in 107 isolates (82.4%). Four types of GIs were identified: Tn6022 (50 isolates; 46.7%), AbaR4 (23 isolates; 21.5%), Tn6166 (10 isolates; 9.3%), and Tn6166/Tn2006 (24 isolates; 22.4%). In the 50 isolates with Tn6022, Tn2006 or Tn2008B, both containing ISAba1-bla OXA-23 , was present in sites other than GIs in 3 or 28 isolates, respectively. In the 10 isolates with Tn6166, Tn2008B was identified in one isolate. AbGRI1-type GIs were identified nearly exclusively in CC208 isolates, with the exception of nine non-CC208 isolates (AbaR4 in eight ST229 isolates and Tn6022 in one ST1244 isolate). Within CC208 isolates, there was evidence of frequent recombination events, in both housekeeping genes and AbGRI1-type GIs, contributing to genotype diversification and the emergence of carbapenem resistance. Copyright © 2017 American Society for Microbiology.

Diversity of β-lactamases produced by imipenem resistant, Pseudomonas aeruginosa isolates from the bloodstream.

PubMed

Najar Peerayeh, Shahin; Pirhajati Mahabadi, Rahim; Pakbaten Toupkanlou, Sanaz; Siadat, Seyed Davar

2014-11-01

The emergence of imipenem non-susceptible Pseudomonas aeruginosa isolates is a matter of great concern because these isolates can become resistant to all available antibiotics. This study conducted to characterize β-lactamase genes in imipenem resistant P. aeruginosa isolates from bloodstream. 56 non-duplicate clinical isolates of P. aeruginosa were collected in Tehran hospitals. Antibacterial susceptibility was determined by disk diffusion and MIC methods. ESBL and MBL production was confirmed by combined disk. β-Lactamase classes A, B and D genes were identified by PCR. Seventeen (30.3%) isolates were imipenem resistant for which 16 isolates simultaneously were resistant to all tested antibiotics. While among 39 imipenem susceptible isolates, only two isolates were resistant to all tested antibiotics. In imipenem resistant isolates, blaTEM, blaSHV and blaOXA-10 were found in 41.1% of isolates and blaVIM, blaIMP and blaPER were identified in 47%, 11.7% and 5.8% of isolates respectively, while in imipenem susceptible isolates, blaTEM, blaSHV and blaOXA-10 were determined in 2.5%, 7.6% and 33.3% of isolates, respectively. The imipenem resistant isolates had been recovered mostly (67.7%) from patients in the Burn hospital. The result of this study indicated the emergence of multidrug resistant MBL and non-MBL producing P. aeruginosa, particularly in the Burn hospital and blaVIM was dominant β-lactamase genes in imipenem resistant isolates. The isolation of carrier patients may lead to prevent a further dissemination. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Molecular epidemiology of Klebsiella pneumoniae K1 and K2 isolates in Japan.

PubMed

Harada, Sohei; Ishii, Yoshikazu; Saga, Tomoo; Aoki, Kotaro; Tateda, Kazuhiro

2018-03-20

Although severe infections caused by hypervirulent Klebsiella pneumoniae isolates, such as K1 isolates belonging to sequence type (ST) 23, have been a significant problem in Asian countries, epidemiology of these isolates in Japan remains unclear. We performed a nationwide molecular epidemiological study of K. pneumoniae K1 and K2 isolates in Japan. Of the 259K. pneumoniae isolates collected, 14 and 16 isolates were identified as capsular genotypes K1 and K2, respectively. All K1 isolates were ST23 or its closely related clones and showed high genetic similarity by pulsed-field gel electrophoresis (PFGE) and the DiversiLab system (DL). K2 isolates, belonging to ST14, ST25, ST65, ST86, and ST110, were more genetically diverse than K1 isolates. Isolates belonging to a specific ST showed identical virulence gene profiles with a few exceptions. PFGE and DL results using K1 and K2 isolates were generally in agreement. Copyright © 2018. Published by Elsevier Inc.

Serovars, bacteriophage types and antimicrobial sensitivities associated with salmonellosis in dogs in the UK (1954-2012).

PubMed

Philbey, A W; Mather, H A; Gibbons, J F; Thompson, H; Taylor, D J; Coia, J E

2014-01-25

Serovars and bacteriophage (phage) types were determined for 442 isolates of Salmonella enterica from dogs in the UK submitted to the Scottish Salmonella Reference Laboratory from 1954 to 2012. The most frequent serovars were Salmonella Typhimurium (196 isolates; 44.3 per cent), Dublin (40 isolates; 9.0 per cent), Enteritidis (28 isolates; 6.3 per cent), Montevideo (19 isolates; 4.3 per cent), Virchow (10 isolates; 2.3 per cent), Heidelberg (8 isolates; 1.8 per cent) and Derby (8 isolates; 1.8 per cent), along with 55 other recognised serovars among 127 other isolates, and six incompletely classified isolates. Serovars were frequently represented by strains commonly associated with poultry, cattle or pigs and their products. Among 196 Salmonella Typhimurium isolates from dogs, the most frequent phage types (definitive types) were the multiple antimicrobial-resistant strains DT104 (62 isolates), DT204c (18 isolates) and DT193 (8 isolates), along with antimicrobial sensitive wild finch strains DT40 (13 isolates) and DT56 variant (8 isolates). Eleven of 28 isolates of Salmonella Enteritidis were phage type 4. S enterica was frequently recovered from faecal or intestinal samples of dogs with diarrhoea, although many dogs had concurrent infection with other enteric pathogens. Salmonella Dublin was recovered from the brain and/or cerebrospinal fluid of two dogs with meningoencephalitis. Salmonella Kedougou was isolated from the joint fluid of a dog with septic arthritis. Salmonella Typhimurium and Salmonella Dublin were each recovered from the vaginas of bitches that had aborted. Isolates of Salmonella Enteritidis phage types 1, 4 and 8, Salmonella Typhimurium DT104, Salmonella Dublin and Salmonella Indiana were isolated from clinically healthy dogs in households where the same strains were recovered from human beings with diarrhoea. The pattern ampicillin-chloramphenicol-spectinomycin-streptomycin-sulfamethoxazole-tetracycline (ACSpSSuT) was the most frequent resistance phenotype and was observed in 44 (13.3 per cent) of 330 isolates. Dogs in the UK are exposed to a wide variety of serovars of S enterica, sometimes associated with clinical disease, and represent a zoonotic risk.

Molecular Mechanisms of Fluoroquinolone Resistance in Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients

PubMed Central

Jalal, Shah; Ciofu, Oana; Høiby, Niels; Gotoh, Naomasa; Wretlind, Bengt

2000-01-01

Twenty P. aeruginosa isolates were collected from six cystic fibrosis (CF) patients, aged 27 to 33, in 1994 (9 isolates) and 1997 (11 isolates) at the CF Center, Copenhagen, Denmark, and were typed by pulse-field gel electrophoresis (PFGE) or ribotyping. Five of the patients had isolates with the same PFGE or ribotyping patterns in 1997 as in 1994, and ciprofloxacin had a two- to fourfold higher MIC for the isolates collected in 1997 than those from 1994. Genomic DNA was amplified for gyrA, parC, mexR, and nfxB by PCR and sequenced. Eleven isolates had mutations in gyrA, seven isolates had mutations at codon 83 (Thr to Ile), and four isolates had mutations at codon 87 (Asp to Asn or Tyr). Sixteen isolates had mutations in nfxB at codon 82 (Arg to Leu). Increased amounts of OprN were found in six isolates and OprJ in eight isolates as determined by immunoblotting. No isolates had mutations in parC or mexR. Six isolates had mutations in efflux pumps without gyrA mutations. The average number of mutations was higher in isolates from 1997 than in those from 1994. The results also suggested that efflux resistance mechanisms are more common in isolates from CF patients than in strains from urine and wounds from non-CF patients, in which mutations in gyrA and parC dominate (S. Jalal and B. Wretlind, Microb. Drug Resist. 4:257–261, 1998). PMID:10681343

Influences of Media Compositions on Characteristics of Isolated Bacteria Exhibiting Lignocellulolytic Activities from Various Environmental Sites.

PubMed

Gong, Gyeongtaek; Lee, Sun-Mi; Woo, Han Min; Park, Tai Hyun; Um, Youngsoon

2017-11-01

Efficient isolation of lignocellulolytic bacteria is essential for the utilization of lignocellulosic biomass. In this study, bacteria with cellulolytic, xylanolytic, and lignolytic activities were isolated from environmental sites such as mountain, wetland, and mudflat using isolation media containing the combination of lignocellulose components (cellulose, xylan, and lignin). Eighty-nine isolates from the isolation media were characterized by analyzing taxonomic ranks and cellulolytic, xylanolytic, and lignolytic activities. Most of the cellulolytic bacteria showed multienzymatic activities including xylanolytic activity. The isolation media without lignin were efficient in isolating bacteria exhibiting multienzymatic activities even including lignolytic activity, whereas a lignin-containing medium was effective to isolate bacteria exhibiting lignolytic activity only. Multienzymatic activities were mainly observed in Bacillus and Streptomyces, while Burkholderia was the most abundant genus with lignolytic activity only. This study provides insight into isolation medium for efficient isolation of lignocellulose-degrading microorganisms.

Characterization of Sphingomonas isolates from Finnish and Swedish drinking water distribution systems.

PubMed

Koskinen, R; Ali-Vehmas, T; Kämpfer, P; Laurikkala, M; Tsitko, I; Kostyal, E; Atroshi, F; Salkinoja-Salonen, M

2000-10-01

Sphingomonas species were commonly isolated from biofilms in drinking water distribution systems in Finland (three water meters) and Sweden (five water taps in different buildings). The Sphingomonas isolates (n = 38) were characterized by chemotaxonomic, physiological and phylogenetic methods. Fifteen isolates were designated to species Sphingomonas aromaticivorans, seven isolates to S. subterranea, two isolates to S. xenophaga and one isolate to S. stygia. Thirteen isolates represented one or more new species of Sphingomonas. Thirty-three isolates out of 38 grew at 5 degrees C on trypticase soy broth agar (TSBA) and may therefore proliferate in the Nordic drinking water pipeline where the temperature typically ranges from 2 to 12 degrees C. Thirty-three isolates out of 38 grew at 37 degrees C on TSBA and 15 isolates also grew on blood agar at 37 degrees C. Considering the potentially pathogenic features of sphingomonas, their presence in drinking water distribution systems may not be desirable.

Correlates of Objective Social Isolation from Family and Friends among Older Adults.

PubMed

Chatters, Linda M; Taylor, Harry Owen; Nicklett, Emily J; Taylor, Robert Joseph

2018-03-03

This study examined the correlates of objective social isolation from extended family members and friends among older adults. The analysis is based on the older adult sub-sample of the National Survey of American Life ( n = 1321). Multinomial logistic regression analyses examined race/ethnicity, demographics, functional health and family and friend network factors as correlates of objective isolation from family and friends. Only 4.47% of respondents were objectively isolated from both their extended family and friends, 10.82% were isolated from their friends, and 7.43% were isolated from their family members. Men were more likely to be objectively isolated from both family and friends and older adults who live with others were significantly more likely to be objectively isolated from their friends. When controlling for subjective social isolation, the two measures of functional health were significantly associated with objective social isolation. In particular, higher levels of self-care impairment decreased the risk of being objectively isolated from friends only, whereas higher mobility impairment was associated with an increased likelihood of being objectively isolated from friends only. Subjective evaluations of social isolation from family and friends were consistently associated with being objectively isolated from family and friends. There were no significant differences between African-Americans, Black Caribbeans and non-Hispanic Whites in objective isolation. These and other findings are discussed in detail.

Correlates of Objective Social Isolation from Family and Friends among Older Adults

PubMed Central

Chatters, Linda M.; Taylor, Harry Owen; Taylor, Robert Joseph

2018-01-01

This study examined the correlates of objective social isolation from extended family members and friends among older adults. The analysis is based on the older adult sub-sample of the National Survey of American Life (n = 1321). Multinomial logistic regression analyses examined race/ethnicity, demographics, functional health and family and friend network factors as correlates of objective isolation from family and friends. Only 4.47% of respondents were objectively isolated from both their extended family and friends, 10.82% were isolated from their friends, and 7.43% were isolated from their family members. Men were more likely to be objectively isolated from both family and friends and older adults who live with others were significantly more likely to be objectively isolated from their friends. When controlling for subjective social isolation, the two measures of functional health were significantly associated with objective social isolation. In particular, higher levels of self-care impairment decreased the risk of being objectively isolated from friends only, whereas higher mobility impairment was associated with an increased likelihood of being objectively isolated from friends only. Subjective evaluations of social isolation from family and friends were consistently associated with being objectively isolated from family and friends. There were no significant differences between African-Americans, Black Caribbeans and non-Hispanic Whites in objective isolation. These and other findings are discussed in detail. PMID:29510504

Optimization of seismic isolation systems via harmony search

NASA Astrophysics Data System (ADS)

Melih Nigdeli, Sinan; Bekdaş, Gebrail; Alhan, Cenk

2014-11-01

In this article, the optimization of isolation system parameters via the harmony search (HS) optimization method is proposed for seismically isolated buildings subjected to both near-fault and far-fault earthquakes. To obtain optimum values of isolation system parameters, an optimization program was developed in Matlab/Simulink employing the HS algorithm. The objective was to obtain a set of isolation system parameters within a defined range that minimizes the acceleration response of a seismically isolated structure subjected to various earthquakes without exceeding a peak isolation system displacement limit. Several cases were investigated for different isolation system damping ratios and peak displacement limitations of seismic isolation devices. Time history analyses were repeated for the neighbouring parameters of optimum values and the results proved that the parameters determined via HS were true optima. The performance of the optimum isolation system was tested under a second set of earthquakes that was different from the first set used in the optimization process. The proposed optimization approach is applicable to linear isolation systems. Isolation systems composed of isolation elements that are inherently nonlinear are the subject of a future study. Investigation of the optimum isolation system parameters has been considered in parametric studies. However, obtaining the best performance of a seismic isolation system requires a true optimization by taking the possibility of both near-fault and far-fault earthquakes into account. HS optimization is proposed here as a viable solution to this problem.

Comparative analysis of phylogenetic relationships, morphologies, and pathogenicities among Curvularia lunata isolates from maize in China.

PubMed

Liu, T; Zhao, F Z; Wang, Y Y; Hou, J M; Liu, L Z; Shen, Y Q; Liu, Z; Zhang, H T; Zuo, Y H

2015-10-16

To understand the effects of disease-resistant maize varieties and new cropping systems on the population of Curvularia lunata, 52 isolates of C. lunata were collected in China from 2011 to 2013. The isolates were analyzed in terms of phylogenetic relationships, morphology, and pathogenicity. Phylogenetic analysis showed that the 52 isolates clustered into 2 distinct clusters with further subdivisions, suggesting the emergence of new genetic divergence within C. lunata. Results of morphology and pathogenicity analyses demonstrated that there were significant differences among these isolates: 27 isolates were classified as fast growing, 5 as slow growing, and 20 as moderate growing. Three isolates had white-colored colonies, 13 had yellowish green-colored colonies, and the remaining isolates had dark green-colored colonies. Furthermore, conidiation rates were assessed: 30 isolates were characterized as having low conidiation rates, 15 as having medium conidiation rates, and the remaining 7 isolates as having high conidiation rates. Eleven of the isolates appeared to be strongly pathogenic against maize, 15 isolates proved to be weakly pathogenic against maize, and the remaining isolates were regarded to be moderately pathogenic. Interestingly, correlation analysis demonstrated a negative correlation between the growth rate and the pathogenicity of the isolates, while a positive correlation was observed between the conidiation rate and the pathogenicity. No correlation was observed between the colony color and the pathogenicity of the isolates.

Dissemination of clonal Salmonella enterica serovar Typhimurium isolates causing salmonellosis in Mauritius.

PubMed

Issack, Mohammad I; Garcia-Migura, Lourdes; Ramsamy, Veemala D; Svendsen, Christina A; Pornruangwong, Srirat; Pulsrikarn, Chaiwat; Hendriksen, Rene S

2013-07-01

Salmonella enterica serotype Typhimurium is one of the leading causes of salmonellosis in Mauritius, where it has also been associated with outbreaks of foodborne illness. However, little is known about its molecular epidemiology in the country. This study was therefore undertaken to investigate the clonality and source of Salmonella Typhimurium in Mauritius by studying human, food, and poultry isolates by pulsed-field gel electrophoresis (PFGE) and antibiotic minimum inhibitory concentration determination. Forty-nine isolates collected between 2008 and 2011 were analyzed, including 25 stool isolates from foodborne illness outbreaks and sporadic gastroenteritis cases, four blood isolates, one postmortem colon isolate, 14 food isolates, and five poultry isolates. All isolates were pansusceptible to the 16 antibiotics tested, except for two isolates that were resistant to sulfamethoxazole and trimethoprim. Overall characterization of the isolates by PFGE digested with XbaI and BlnI resulted in eight different patterns. The largest of the clusters in the composite dataset consisted of 20 isolates, including two raw chicken isolates, four poultry isolates, and nine human stool isolates from two outbreaks. A second cluster consisted of 18 isolates, of which 12 originated from human blood and stool samples from both sporadic and outbreak cases. Six food isolates were also found in this cluster, including isolates from raw and grilled chicken, marlin mousse, and cooked pork. One poultry isolate had a closely related PFGE pattern. The results indicate that one clone of Salmonella Typhimurium found in poultry has been causing outbreaks of foodborne illness in Mauritius and another clone that has caused many cases of gastrointestinal illness and bacteremia in humans could also be linked to poultry. Thus, poultry appears to be a major reservoir for Salmonella Typhimurium in Mauritius. Initiating on-farm control strategies and measures against future dissemination may substantially reduce the number of cases of salmonellosis in the country.

42 CFR 71.33 - Persons: Isolation and surveillance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Persons: Isolation and surveillance. 71.33 Section...: Isolation and surveillance. (a) Persons held in isolation under this subpart may be held in facilities suitable for isolation and treatment. (b) The Director may require isolation where surveillance is...

42 CFR 71.33 - Persons: Isolation and surveillance.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Persons: Isolation and surveillance. 71.33 Section...: Isolation and surveillance. (a) Persons held in isolation under this subpart may be held in facilities suitable for isolation and treatment. (b) The Director may require isolation where surveillance is...

42 CFR 71.33 - Persons: Isolation and surveillance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Persons: Isolation and surveillance. 71.33 Section...: Isolation and surveillance. (a) Persons held in isolation under this subpart may be held in facilities suitable for isolation and treatment. (b) The Director may require isolation where surveillance is...

42 CFR 71.33 - Persons: Isolation and surveillance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Persons: Isolation and surveillance. 71.33 Section...: Isolation and surveillance. (a) Persons held in isolation under this subpart may be held in facilities suitable for isolation and treatment. (b) The Director may require isolation where surveillance is...

42 CFR 71.33 - Persons: Isolation and surveillance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Persons: Isolation and surveillance. 71.33 Section...: Isolation and surveillance. (a) Persons held in isolation under this subpart may be held in facilities suitable for isolation and treatment. (b) The Director may require isolation where surveillance is...

Effect of isolation techniques on the characteristics of pigeon pea (Cajanus cajan) protein isolates.

PubMed

Adenekan, Monilola K; Fadimu, Gbemisola J; Odunmbaku, Lukumon A; Oke, Emmanuel K

2018-01-01

In this study, the effect of different isolation techniques on the isolated proteins from pigeon pea was investigated. Water, methanol, ammonium sulfate, and acetone were used for the precipitation of proteins from pigeon pea. Proximate composition, and antinutritional and functional properties of the pigeon pea flour and the isolated proteins were measured. Data generated were statistically analyzed. The proximate composition of the water-extracted protein isolate was moisture 8.30%, protein 91.83%, fat 0.25%, ash 0.05%, and crude fiber 0.05%. The methanol-extracted protein isolate composition was moisture 7.87%, protein 91.83%, fat 0.17%, and ash 0.13%, while crude fiber and carbohydrates were not detected. The composition of the ammonium sulfate-extracted protein isolate was moisture 7.73%, protein 91.73%, fat 0.36, ash 0.13%, and crude fiber 0.67%. The acetone-extracted protein isolate composition was moisture 8.03%, protein 91.50%, ash 0.67%, and fat 0.30%, but crude fiber and carbohydrates were not detected. The isolate precipitated with ammonium sulfate displayed the highest foaming capacity (37.63%) and foaming stability (55.75%). Isolates precipitated with methanol and acetone had the highest water absorption capacity (160%). Pigeon pea protein isolates extracted with methanol and ammonium sulfate had the highest oil absorption capacity of 145%. Protein isolates recovered through acetone and methanol had the highest emulsifying capacity of 2.23% and emulsifying stability of 91.47%, respectively. The proximate composition of the recovered protein isolates were of high purity. This shows the efficiency of the extraction techniques. The isolates had desirable solubility index. All the isolation techniques brought significant impact on the characteristics of the isolated pigeon pea protein.

Multi-drug resistant oral Candida species isolated from HIV-positive patients in South Africa and Cameroon.

PubMed

Dos Santos Abrantes, Pedro Miguel; McArthur, Carole P; Africa, Charlene Wilma Joyce

2014-06-01

Candida species are a common cause of infection in immune-compromised HIV-positive individuals, who are usually treated with the antifungal drug, fluconazole, in public hospitals in Africa. However, information about the prevalence of drug resistance to fluconazole and other antifungal agents on Candida species is very limited. This study examined 128 Candida isolates from South Africa and 126 Cameroonian Candida isolates for determination of species prevalence and antifungal drug susceptibility. The isolates were characterized by growth on chromogenic and selective media and by their susceptibility to 9 antifungal drugs tested using the TREK™ YeastOne9 drug panel (Thermo Scientific, USA). Eighty-three percent (82.8%) of South African isolates were Candida albicans (106 isolates), 9.4% were Candida glabrata (12 isolates), and 7.8% were Candida dubliniensis (10 isolates). Of the Cameroonian isolates, 73.02% were C. albicans (92 isolates); 19.05% C. glabrata (24 isolates); 3.2% Candida tropicalis (4 isolates); 2.4% Candida krusei (3 isolates); 1.59% either Candida kefyr, Candida parapsilopsis, or Candida lusitaneae (2 isolates); and 0.79% C. dubliniensis (1 isolate). Widespread C. albicans resistance to azoles was detected phenotypically in both populations. Differences in drug resistance were seen within C. glabrata found in both populations. Echinocandin drugs were more effective on isolates obtained from the Cameroon than in South Africa. A multiple-drug resistant C. dubliniensis strain isolated from the South African samples was inhibited only by 5-flucytosine in vitro on the YO9 panel. Drug resistance among oral Candida species is common among African HIV patients in these 2 countries. Regional surveillance of Candida species drug susceptibility should be undertaken to ensure effective treatment for HIV-positive patients. Copyright © 2014 Elsevier Inc. All rights reserved.

Characterization of Encapsulated and Noncapsulated Haemophilus influenzae and Determination of Phylogenetic Relationships by Multilocus Sequence Typing

PubMed Central

Meats, Emma; Feil, Edward J.; Stringer, Suzanna; Cody, Alison J.; Goldstein, Richard; Kroll, J. Simon; Popovic, Tanja; Spratt, Brian G.

2003-01-01

A multilocus sequence typing (MLST) scheme has been developed for the unambiguous characterization of encapsulated and noncapsulated Haemophilus influenzae isolates. The sequences of internal fragments of seven housekeeping genes were determined for 131 isolates, comprising a diverse set of 104 serotype a, b, c, d, e, and f isolates and 27 noncapsulated isolates. Many of the encapsulated isolates had previously been characterized by multilocus enzyme electrophoresis (MLEE), and the validity of the MLST scheme was established by the very similar clustering of isolates obtained by these methods. Isolates of serotypes c, d, e, and f formed monophyletic groups on a dendrogram constructed from the differences in the allelic profiles of the isolates, whereas there were highly divergent lineages of both serotype a and b isolates. Noncapsulated isolates were distinct from encapsulated isolates and, with one exception, were within two highly divergent clusters. The relationships between the major lineages of encapsulated H. influenzae inferred from MLEE data could not be discerned on a dendrogram constructed from differences in the allelic profiles, but were apparent on a tree reconstructed from the concatenated nucleotide sequences. Recombination has not therefore completely eliminated phylogenetic signal, and in support of this, for encapsulated isolates, there was significant congruence between many of the trees reconstructed from the sequences of the seven individual loci. Congruence was less apparent for noncapsulated isolates, suggesting that the impact of recombination is greater among noncapsulated than encapsulated isolates. The H. influenzae MLST scheme is available at www.mlst.net, it allows any isolate to be compared with those in the MLST database, and (for encapsulated isolates) it assigns isolates to their phylogenetic lineage, via the Internet. PMID:12682154

New Paenibacillus larvae bacterial isolates from honey bee colonies infected with American foulbrood disease in Egypt.

PubMed

Masry, Saad Hamdy Daif; Kabeil, Sanaa Soliman; Hafez, Elsayed Elsayed

2014-03-04

The American foulbrood disease is widely distributed all over the world and causes a serious problem for the honeybee industry. Different infected larvae were collected from different apiaries, ground in phosphate saline buffer (PSB) and bacterial isolation was carried out on nutrient agar medium. Different colonies were observed and were characterized biologically. Two bacterial isolates (SH11 and SH33) were subjected to molecular identification using 16S rRNA gene and the sequence analysis revealed that the two isolates are Paenibacillus larvae with identity not exceeding 83%. The DNA sequence alignment between the other P. larvae bacterial strains and the two identified bacterial isolates showed that all the examined bacterial strains have the same ancestor, i.e. they have the same origin. The SH33 isolate was closely related to the P. larvae isolated from Germany, whereas the isolate SH11 was close to the P. larvae isolated from India. The phylogenetic tree constructed for 20 different Bacillus sp. and the two isolates SH11 and SH33 demonstrated that the two isolates are Bacillus sp. and they are new isolates. The bacterial isolates will be subjected to more tests for more confirmations.

The distribution of beta lactamase genes in Escherichia coli phylotypes isolated from diarrhea and UTI cases in northwest Iran.

PubMed

Hemati, Zahra; Ghanbarpour, Reza; Alizade, Hesam

2014-01-01

Pathogenic Escherichia coli strains are a common cause of intestinal and extra-intestinal infections, especially in developing countries. Extended spectrum beta-lactamases (ESBLS), a heterogeneous group of plasmid-encoded beta-lactamases, are common throughout the world. The aim of the present study was to determine the phenotypic and genotypic characteristics of ESBLS produced by E. coli isolates taken from patients with diarrhea and urinary tract infections (UTI) in northwest Iran. A total of 132 E. coli isolates (92 isolates from UTI and 40 isolates from diarrheic cases) were recovered and confirmed by biochemical tests. The isolates were examined for blaTEM and blaSHV genes and phylogenetic background by two multiplex PCR assays. The isolates were tested for antibiotic susceptibility against nine antibiotic agents by the disk diffusion method. The phylogenetic analysis showed that the UTI isolates mostly fell into phylo-group B2, followed by D, while the diarrheic isolates belonged to phylo-groups D and A. Out of 92 UTI isolates, 29.3% and 17.4% possessed blaTEM and blaSHV genes, respectively. Ten diarrheic isolates were positive for blaTEM, two isolates possessed the blaSHV gene, and one isolate was positive for both genes. The UTI isolates that were positive for blaTEM and blaSHV genes mostly belonged to phylo-groups D and B2, whereas the diarrhea isolates were in phylo-groups D and A. Phylogenetic group D isolates have an accumulation of ESBLS genes in the diarrheic and UTI isolates. In both the UTI and diarrhea isolates, the maximum rate of resistance was against cefazolin, and the minimum rate of resistance was against nitrofurantoin. Twenty-four antibiotic resistance patterns were observed among the isolates. The amikacin, ciprofloxacin, cefotaxime, cefuroxime, cefazolin, gentamicin, nalidixic acid and trimethoprim/sulfamethoxazole resistance pattern was the most prevalent in the isolates that belonged to phylo-group D. The correct choice of effective antibiotic policy is needed to limit the spread of antibiotic resistance in bacteria.

Survey of Active Vibration Isolation Systems for Microgravity Applications

NASA Technical Reports Server (NTRS)

Grodsinsky, Carlos M.; Whorton, Mark S.

2000-01-01

In view of the utility of space vehicles as orbiting science laboratories, the need for vibration isolation systems for acceleration-sensitive experiments has gained increasing visibility. To date, three active microgravity vibration isolation systems have successfully been demonstrated in flight. A tutorial discussion of the microgravity vibration isolation problem, including a description of the acceleration environment of the International Space Station and attenuation requirements, as well as a comparison or the dynamics of passive isolation, active rack-level isolation, and active payload-level isolation is provided. The flight test results of the three demonstrated systems: suppression of transient accelerations by levitation, the microgravity vibration isolation mount, and the active rack isolation system are surveyed.

Comparative analysis of virulence and resistance profiles of Salmonella Enteritidis isolates from poultry meat and foodborne outbreaks in northern Jordan

PubMed Central

Jaradat, Ziad W; Abedel Hafiz, Leena; Ababneh, Mustafa M; Ababneh, Qotaibah O; Al Mousa, Waseem; Al-Nabulsi, Anas; Osaili, Tareq M; Holley, Richard

2014-01-01

This study was conducted to isolate Salmonella Enteritidis from poultry samples and compare their virulence and antibiotic resistance profiles to S. Enteritidis isolated from outbreaks in northern Jordan. Two hundred presumptive isolates were obtained from 302 raw poultry samples and were subjected to further analysis and confirmation. A phylogenic tree based on 16S rRNA sequencing was constructed and selected isolates representing each cluster were further studied for their virulence in normal adult Swiss white mice. The most virulent strains were isolated from poultry samples and had an LD50 of 1.55 × 105 CFU, while some of the outbreak isolates were avirulent in mice. Antibiotic resistance profiling revealed that the isolates were resistant to seven of eight antibiotics screened with each isolate resistant to multiple antibiotics (from two to six). Of the poultry isolates, 100%, 88.9%, 77.8%, 66.7%, and 50% showed resistance to nalidixic acid, ciprofloxacin, ampicillin, cephalothin, and cefoperazone, respectively. Two outbreak isolates were sensitive to all tested antibiotics, while 71.4% were resistant to cefoperazone and only 28.6% showed resistance to nalidixic acid. Salmonella outbreak isolates were genetically related to poultry isolates as inferred from the 16S rRNA sequencing, yet were phenotypically different. Although outbreak strains were similar to poultry isolates, when tested in the mouse model, some of the outbreak isolates were highly virulent while others were avirulent. This might be due to a variation in susceptibility of the mouse to different S. Enteritidis isolates. PMID:24780883

Characterization of bacterial isolates from the microbiota of mothers' breast milk and their infants

PubMed Central

Kozak, Kimberly; Charbonneau, Duane; Sanozky-Dawes, Rosemary; Klaenhammer, Todd

2015-01-01

This investigation assessed the potential of isolating novel probiotics from mothers and their infants. A subset of 21 isolates among 126 unique bacteria from breast milk and infant stools from 15 mother-infant pairs were examined for simulated GI transit survival, adherence to Caco-2 cells, bacteriocin production, and lack of antibiotic resistance. Of the 21 selected isolates a Lactobacillus crispatus isolate and 3 Lactobacillus gasseri isolates demonstrated good profiles of in vitro GI transit tolerance and Caco-2 cell adherence. Bacteriocin production was observed only by L. gasseri and Enterococcus faecalis isolates. Antibiotic resistance was widespread, although not universal, among isolates from infants. Highly similar isolates (≥ 97% similarity by barcode match) of Bifidobacterium longum subsp. infantis (1 match), Lactobacillus fermentum (2 matches), Lactobacillus gasseri (6 matches), and Enterococcus faecalis (1 match) were isolated from 5 infant–mother pairs. Antibiotic resistance profiles between these isolate matches were similar, except in one case where the L. gasseri isolate from the infant exhibited resistance to erythromycin and tetracycline, not observed in matching mother isolate. In a second case, L. gasseri isolates differed in resistance to ampicillin, chloramphenicol and vancomycin between the mother and infant. In this study, gram positive bacteria isolated from mothers' breast milk as well as their infants exhibited diversity in GI transit survival and acid inhibition of pathogens, but demonstrated limited ability to produce bacteriocins. Mothers and their infants offer the potential for identification of probiotics; however, even in the early stages of development, healthy infants contain isolates with antibiotic resistance. PMID:26727418

Characterization of bacterial isolates from the microbiota of mothers' breast milk and their infants.

PubMed

Kozak, Kimberly; Charbonneau, Duane; Sanozky-Dawes, Rosemary; Klaenhammer, Todd

2015-01-01

This investigation assessed the potential of isolating novel probiotics from mothers and their infants. A subset of 21 isolates among 126 unique bacteria from breast milk and infant stools from 15 mother-infant pairs were examined for simulated GI transit survival, adherence to Caco-2 cells, bacteriocin production, and lack of antibiotic resistance. Of the 21 selected isolates a Lactobacillus crispatus isolate and 3 Lactobacillus gasseri isolates demonstrated good profiles of in vitro GI transit tolerance and Caco-2 cell adherence. Bacteriocin production was observed only by L. gasseri and Enterococcus faecalis isolates. Antibiotic resistance was widespread, although not universal, among isolates from infants. Highly similar isolates (≥ 97% similarity by barcode match) of Bifidobacterium longum subsp. infantis (1 match), Lactobacillus fermentum (2 matches), Lactobacillus gasseri (6 matches), and Enterococcus faecalis (1 match) were isolated from 5 infant-mother pairs. Antibiotic resistance profiles between these isolate matches were similar, except in one case where the L. gasseri isolate from the infant exhibited resistance to erythromycin and tetracycline, not observed in matching mother isolate. In a second case, L. gasseri isolates differed in resistance to ampicillin, chloramphenicol and vancomycin between the mother and infant. In this study, gram positive bacteria isolated from mothers' breast milk as well as their infants exhibited diversity in GI transit survival and acid inhibition of pathogens, but demonstrated limited ability to produce bacteriocins. Mothers and their infants offer the potential for identification of probiotics; however, even in the early stages of development, healthy infants contain isolates with antibiotic resistance.

Isolation barriers between petunia axillaris and Petunia integrifolia (Solanaceae).

PubMed

Dell'olivo, Alexandre; Hoballah, Maria Elena; Gübitz, Thomas; Kuhlemeier, Cris

2011-07-01

The isolation barriers restricting gene flow between populations or species are of crucial interest for understanding how biological species arise and how they are maintained. Few studies have examined the entire range of possible isolation barriers from geographic isolation to next generation hybrid viability. Here, we present a detailed analysis of isolation barriers between two flowering plant species of the genus Petunia (Solanaceae). Petunia integrifolia and P. axillaris feature divergent pollination syndromes but can produce fertile hybrids when crossed in the laboratory. Both Petunia species are primarily isolated in space but appear not to hybridize in sympatry. Our experiments demonstrate that pollinator isolation is very high but not strong enough to explain the absence of hybrids in nature. However, pollinator isolation in conjunction with male gametic isolation (i.e., pollen-pistil interaction) can explain the lack of natural hybridization, while postzygotic isolation barriers are low or nonexistent. Our study supports the notion that reproductive isolation in flowering plants is mainly caused by pre- rather than postzygotic isolation mechanisms. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Improved hybrid isolator with maglev actuator integrated in air spring for active-passive isolation of ship machinery vibration

NASA Astrophysics Data System (ADS)

Li, Yan; He, Lin; Shuai, Chang-geng; Wang, Chun-yu

2017-10-01

A hybrid isolator consisting of maglev actuator and air spring is proposed and developed for application in active-passive vibration isolation system of ship machinery. The dynamic characteristics of this hybrid isolator are analyzed and tested. The stability and adaptability of this hybrid isolator to shock and swing in the marine environment are improved by a compliant gap protection technique and a disengageable suspended structure. The functions of these new engineering designs are proved by analytical verification and experimental validation of the designed stiffness of such a hybrid isolator, and also by shock adaptability testing of the hybrid isolator. Finally, such hybrid isolators are installed in an engineering mounting loaded with a 200-kW ship diesel generator, and the broadband and low-frequency sinusoidal isolation performance is tested.

Characterization of Novel Trichoderma asperellum Isolates to Select Effective Biocontrol Agents Against Tomato Fusarium Wilt

PubMed Central

El_Komy, Mahmoud H.; Saleh, Amgad A.; Eranthodi, Anas; Molan, Younes Y.

2015-01-01

The use of novel isolates of Trichoderma with efficient antagonistic capacity against Fusarium oxysporum f. sp. lycopersici (FOL) is a promising alternative strategy to pesticides for tomato wilt management. We evaluated the antagonistic activity of 30 isolates of T. asperellum against 4 different isolates of FOL. The production of extracellular cell wall degrading enzymes of the antagonistic isolates was also measured. The random amplified polymorphic DNA (RAPD) method was applied to assess the genetic variability among the T. asperellum isolates. All of the T. asperellum isolates significantly reduced the mycelial growth of FOL isolates but the amount of growth reduction varied significantly as well. There was a correlation between the antagonistic capacity of T. asperellum isolates towards FOL and their lytic enzyme production. Isolates showing high levels of chitinase and β-1,3-glucanase activities strongly inhibited the growth of FOL isolates. RAPD analysis showed a high level of genetic variation among T. asperellum isolates. The UPGMA dendrogram revealed that T. asperellum isolates could not be grouped by their anta- gonistic behavior or lytic enzymes production. Six isolates of T. asperellum were highly antagonistic towards FOL and potentially could be used in commercial agriculture to control tomato wilt. Our results are consistent with the conclusion that understanding the genetic variation within Trichoderma isolates and their biochemical capabilities are required for the selection of effective indigenous fungal strains for the use as biocontrol agents. PMID:25774110

Effect of social isolation on anxiety-related behaviors, cortisol, and monoamines in adult zebrafish.

PubMed

Shams, Soaleha; Seguin, Diane; Facciol, Amanda; Chatterjee, Diptendu; Gerlai, Robert

2017-12-01

Social isolation can be used to study behavioral, neural, and hormonal mechanisms that regulate interactions in social animals. Although isolation effects have been reported in social mammals and various fish species, systematic studies with isolated zebrafish are rare. Here, the authors examined behavior (social and nonsocial), physiological stress (whole-body cortisol levels), and neurochemicals (serotonin, dopamine, and their metabolites), following acute and chronic social isolation in adult zebrafish. To observe how isolated fish respond behaviorally to social stimuli, they exposed zebrafish to live conspecifics or animated images after acute (24 hr) or chronic (6 months) social isolation. The authors observed that isolation did not affect locomotor activity, but acute isolation had weak nonsignificant anxiogenic effects in adult zebrafish. They also found that all isolated fish responded to both live and animated social stimuli, and the stress hormone, cortisol was lower in chronically isolated fish. Finally, neurochemical analyses showed that serotonin levels increased when fish were exposed to social stimulus after acute isolation, but its metabolite 5HIAA decreased in response to social stimulus following both acute and chronic isolation. Levels of both dopamine and its metabolite DOPAC were also reduced in fish exposed to social stimulus after acute and chronic isolation. Overall, these results show that isolation in zebrafish is an effective tool to study fundamental mechanisms controlling social interaction at behavioral and physiological levels. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Whole genome sequencing of Mycobacterium bovis to obtain molecular fingerprints in human and cattle isolates from Baja California, Mexico.

PubMed

Sandoval-Azuara, Sarai Estrella; Muñiz-Salazar, Raquel; Perea-Jacobo, Ricardo; Robbe-Austerman, Suelee; Perera-Ortiz, Alejandro; López-Valencia, Gilberto; Bravo, Doris M; Sanchez-Flores, Alejandro; Miranda-Guzmán, Daniela; Flores-López, Carlos Alberto; Zenteno-Cuevas, Roberto; Laniado-Laborín, Rafael; de la Cruz, Fabiola Lafarga; Stuber, Tod P

2017-10-01

To determine genetic diversity by comparing the whole genome sequences of cattle and human Mycobacterium bovis isolates from Baja California. A whole genome sequencing strategy was used to obtain the molecular fingerprints of 172 isolates of M. bovis obtained from Baja California, Mexico; 155 isolates were from cattle and 17 isolates were from humans. Spoligotypes were characterized in silico and single nucleotide polymorphism (SNP) differences between the isolates were evaluated. A total of 12 M. bovis spoligotype patterns were identified in cattle and humans. Two predominant spoligotypes patterns were seen in both cattle and humans: SB0145 and SB1040. The SB0145 spoligotype represented 59% of cattle isolates (n=91) and 65% of human isolates (n=11), while the SB1040 spoligotype represented 30% of cattle isolates (n=47) and 30% of human isolates (n=5). When evaluating SNP differences, the human isolates were intimately intertwined with the cattle isolates. All isolates from humans had spoligotype patterns that matched those observed in the cattle isolates, and all human isolates shared common ancestors with cattle in Baja California based on SNP analysis. This suggests that most human tuberculosis caused by M. bovis in Baja California is derived from M. bovis circulating in Baja California cattle. These results reinforce the importance of bovine tuberculosis surveillance and control in this region. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Multicenter study evaluating the Vitek MS system for identification of medically important yeasts.

PubMed

Westblade, Lars F; Jennemann, Rebecca; Branda, John A; Bythrow, Maureen; Ferraro, Mary Jane; Garner, Omai B; Ginocchio, Christine C; Lewinski, Michael A; Manji, Ryhana; Mochon, A Brian; Procop, Gary W; Richter, Sandra S; Rychert, Jenna A; Sercia, Linda; Burnham, Carey-Ann D

2013-07-01

The optimal management of fungal infections is correlated with timely organism identification. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) is revolutionizing the identification of yeasts isolated from clinical specimens. We present a multicenter study assessing the performance of the Vitek MS system (bioMérieux) in identifying medically important yeasts. A collection of 852 isolates was tested, including 20 Candida species (626 isolates, including 58 C. albicans, 62 C. glabrata, and 53 C. krusei isolates), 35 Cryptococcus neoformans isolates, and 191 other clinically relevant yeast isolates; in total, 31 different species were evaluated. Isolates were directly applied to a target plate, followed by a formic acid overlay. Mass spectra were acquired using the Vitek MS system and were analyzed using the Vitek MS v2.0 database. The gold standard for identification was sequence analysis of the D2 region of the 26S rRNA gene. In total, 823 isolates (96.6%) were identified to the genus level and 819 isolates (96.1%) were identified to the species level. Twenty-four isolates (2.8%) were not identified, and five isolates (0.6%) were misidentified. Misidentified isolates included one isolate of C. albicans (n = 58) identified as Candida dubliniensis, one isolate of Candida parapsilosis (n = 73) identified as Candida pelliculosa, and three isolates of Geotrichum klebahnii (n = 6) identified as Geotrichum candidum. The identification of clinically relevant yeasts using MS is superior to the phenotypic identification systems currently employed in clinical microbiology laboratories.

Characterization of Colletotrichum acutatum Causing Anthracnose of Anemone (Anemone coronaria L.)†

PubMed Central

Freeman, Stanley; Shabi, Ezra; Katan, Talma

2000-01-01

Anthracnose, or leaf-curl disease of anemone, caused by Colletotrichum sp., has been reported to occur in Australia, western Europe, and Japan. Symptoms include tissue necrosis, corm rot, leaf crinkles, and characteristic spiral twisting of floral peduncles. Three epidemics of the disease have been recorded in Israel: in 1978, in 1990 to 1993, and in 1996 to 1998. We characterized 92 Colletotrichum isolates associated with anthracnose of anemone (Anemone coronaria L.) for vegetative compatibility (72 isolates) and for molecular genotype (92 isolates) and virulence (4 isolates). Eighty-six of the isolates represented the three epidemics in Israel, one isolate was from Australia, and five isolates originated from western Europe. We divided these isolates into three vegetative-compatibility groups (VCGs). One VCG (ANE-A) included all 10 isolates from the first and second epidemics, and 13 of 62 examined isolates from the third epidemic in Israel, along with the isolate from Australia and 4 of 5 isolates from Europe. Another VCG (ANE-F) included most of the examined isolates (49 of the 62) from the third epidemic, as well as Colletotrichum acutatum from strawberry, in Israel. Based on PCR amplification with species-specific primers, all of the anemone isolates were identified as C. acutatum. Anemone and strawberry isolates of the two VCGs were genotypically similar and indistinguishable when compared by arbitrarily primed PCR of genomic DNA. Only isolate NL-12 from The Netherlands, confirmed as C. acutatum but not compatible with either VCG, had a distinct genotype; this isolate represents a third VCG of C. acutatum. Isolates from anemone and strawberry could infect both plant species in artificial inoculations. VCG ANE-F was recovered from natural infections of both anemone and strawberry, but VCG ANE-A was recovered only from anemone. This study of C. acutatum from anemone illustrates the potential of VCG analysis to reveal distinct subspecific groups within a pathogen population which appears to be genotypically homogeneous by molecular assays. PMID:11097901

Comparison of virulence and antibiotic resistance genes of food poisoning outbreak isolates of Staphylococcus aureus with isolates obtained from bovine mastitis milk and pig carcasses.

PubMed

Johler, Sophia; Layer, Franziska; Stephan, Roger

2011-11-01

Staphylococcus aureus is the etiological agent in a variety of infections in humans and livestock and produces enterotoxins leading to staphylococcal food poisoning (SFP), one of the most prevalent foodborne intoxication diseases worldwide. Pork and bovine milk are considered possible sources of SFP because pig skin is often colonized by S. aureus and bovine mastitis caused by S. aureus is common, but conclusive data are limited. The objective of the present study was to compare S. aureus isolates associated with cases of SFP with isolates obtained from bovine mastitis milk and pig carcasses. DNA microarray analysis and spa gene typing were performed with 100 S. aureus isolates: 20 isolates related to outbreaks of SFP in humans, 39 isolates obtained from pig carcasses, and 41 isolates collected from bovine mastitis milk. No overlap in spa types was observed for SFP isolates (t008, t015, t018, t024, t056, t084, t279, t377, t383, t648, t733, t912, t1239, t1270, t4802, and t6969) and isolates gathered from milk or pork. The porcine isolates were assigned to t034, t208, t337, t524, t899, t1939, t2922, t2971, t4475, and t7006, and the bovine isolates belonged to t267, t524, t529, t1403, t2953, t7007, t7008, and t7013. Comparison of microarray profiles revealed similar virulence gene patterns for isolates collected from the same host (pigs or cattle) but few similarities between SFP isolate profiles and the profiles of isolates obtained from bovine mastitis milk and pig carcasses. Although only some bovine and porcine isolates possessed the β-lactamase gene blaZ (milk, 24%; pork, 28%), significantly higher numbers of SFP isolates contained blaZ (90%). Investigations of these isolates provided no evidence that pork or bovine mastitis milk represent common sources of SFP.

Seismic isolation of Advanced LIGO: Review of strategy, instrumentation and performance

NASA Astrophysics Data System (ADS)

Matichard, F.; Lantz, B.; Mittleman, R.; Mason, K.; Kissel, J.; Abbott, B.; Biscans, S.; McIver, J.; Abbott, R.; Abbott, S.; Allwine, E.; Barnum, S.; Birch, J.; Celerier, C.; Clark, D.; Coyne, D.; DeBra, D.; DeRosa, R.; Evans, M.; Foley, S.; Fritschel, P.; Giaime, J. A.; Gray, C.; Grabeel, G.; Hanson, J.; Hardham, C.; Hillard, M.; Hua, W.; Kucharczyk, C.; Landry, M.; Le Roux, A.; Lhuillier, V.; Macleod, D.; Macinnis, M.; Mitchell, R.; O'Reilly, B.; Ottaway, D.; Paris, H.; Pele, A.; Puma, M.; Radkins, H.; Ramet, C.; Robinson, M.; Ruet, L.; Sarin, P.; Shoemaker, D.; Stein, A.; Thomas, J.; Vargas, M.; Venkateswara, K.; Warner, J.; Wen, S.

2015-09-01

The new generation of gravitational waves detectors require unprecedented levels of isolation from seismic noise. This article reviews the seismic isolation strategy and instrumentation developed for the Advanced LIGO observatories. It summarizes over a decade of research on active inertial isolation and shows the performance recently achieved at the Advanced LIGO observatories. The paper emphasizes the scientific and technical challenges of this endeavor and how they have been addressed. An overview of the isolation strategy is given. It combines multiple layers of passive and active inertial isolation to provide suitable rejection of seismic noise at all frequencies. A detailed presentation of the three active platforms that have been developed is given. They are the hydraulic pre-isolator, the single-stage internal isolator and the two-stage internal isolator. The architecture, instrumentation, control scheme and isolation results are presented for each of the three systems. Results show that the seismic isolation sub-system meets Advanced LIGO’s stringent requirements and robustly supports the operation of the two detectors.

Differentiation of Colletotrichum species responsible for anthracnose of strawberry by arbitrarily primed PCR

USGS Publications Warehouse

Freeman, S.; Rodriguez, R.J.

1995-01-01

A collection of 39 isolates of Colletotrichum acutatum, C. fragariae and C. gloeosporioides, which cause anthracnose on strawberry, was grouped into species based on the arbitrarily primed polymerase chain reaction (ap-PCR). All isolates used had previously been identified according to classical taxonomic morphology. Ap-PCR amplification of genomic DNA using four different primers allowed for reliable differentiation between isolates of C. acutatum, C. fragariae and two genotypes of C. gloeosporioides. Fifteen of the 18 C. acutatum isolates were very similar, although three isolates which produced a red pigment had distinctly different banding patterns. Nearly identical banding patterns were observed for all nine isolates of C. fragariae. The 12 C. gloeosporioides isolates were more diverse and two separate genotypes, Cgl-1 (six isolates) and Cgl-2 (five isolates) were distinguished by ap-PCR. An additional isolate did not conform to either the Cgl-1 or Cgl-2 genotypes. The utility of ap-PCR compared with other molecular techniques for reliable identification of Colletotrichum isolates pathogenic on strawberry is discussed.

Characterization and Epidemiology of Pigeon Paramyxovirus Type-1 Viruses (PPMV-1) Isolated in Macedonia.

PubMed

Dodovski, A; Cvetkovikj, I; Krstevski, K; Naletoski, I; Savić, Vladimir

2017-06-01

We have characterized in this study 10 PPMV-1 isolated from domestic pigeons and one PPMV-1 isolated from a feral pigeon in the period 2007-2012, using both classical methods (HI test and ICPI test) and molecular methods (RT-qPCR, RT-PCR, and nucleotide sequencing). Using phylogenetic analysis of partial fusion gene sequences, these viruses clustered with recent European PPMV-1 isolates (EU/re) within the genotype VIb/1. All isolates possessed virulent cleavage site motifs with variable morbidity and mortality in pigeons. The intracerebral pathogenecity indices of the five isolates ranged from 0.59 to 1.53. The repetitive isolation of PPMV-1 viruses for several consecutive years led toward establishing enzootic presence of the disease in pigeons. A high nucleotide sequence homology between the Macedonian isolates and EU/re isolates was shown. Co-circulation of different isolates in the same holdings was detected. This is the first study to extensively describe the molecular epidemiology of PPMV-1 isolated in Macedonia.

Identification of Mucorales From Clinical Specimens: A 4-Year Experience in a Single Institution

PubMed Central

Yang, Mina; Lee, Jang Ho; Kim, Young-Kwon; Ki, Chang-Seok

2016-01-01

Mucormycosis, a fatal opportunistic infection in immunocompromised hosts, is caused by fungi belonging to the order Mucorales. Early diagnosis based on exact identification and multidisciplinary treatments is critical. However, identification of Mucorales fungi is difficult and often delayed, resulting in poor prognosis. This study aimed to compare the results of phenotypic and molecular identification of 12 Mucorales isolates collected from 4-yr-accumulated data. All isolates were identified on the basis of phenotypic characteristics such as growth rate, colony morphology, and reproductive structures. PCR and direct sequencing were performed to target internal transcribed spacer (ITS) and/or D1/D2 regions. Target DNA sequencing identified five Lichtheimia isolates, two Rhizopus microsporus isolates, two Rhizomucor pusillus isolates, one Cunninghamella bertholletiae isolate, one Mucor fragilis isolate, and one Syncephalastrum racemosum isolate. Five of the 12 (41.7%) isolates were incorrectly identified on the basis of phenotypic identification. DNA sequencing showed that of these five isolates, two were Lichtheimia isolates, one was Mucor isolate, one was Rhizomucor isolate, and one was Rhizopus microspores. All the isolates were identified at the species level by ITS and/or D1/D2 analyses. Phenotypic differentiation and identification of Mucorales is difficult because different Mucorales share similar morphology. Our results indicate that the molecular methods employed in this study are valuable for identifying Mucorales. PMID:26522761

Identification of mucorales from clinical specimens: a 4-year experience in a single institution.

PubMed

Yang, Mina; Lee, Jang Ho; Kim, Young Kwon; Ki, Chang Seok; Huh, Hee Jae; Lee, Nam Yong

2016-01-01

Mucormycosis, a fatal opportunistic infection in immunocompromised hosts, is caused by fungi belonging to the order Mucorales. Early diagnosis based on exact identification and multidisciplinary treatments is critical. However, identification of Mucorales fungi is difficult and often delayed, resulting in poor prognosis. This study aimed to compare the results of phenotypic and molecular identification of 12 Mucorales isolates collected from 4-yr-accumulated data. All isolates were identified on the basis of phenotypic characteristics such as growth rate, colony morphology, and reproductive structures. PCR and direct sequencing were performed to target internal transcribed spacer (ITS) and/or D1/D2 regions. Target DNA sequencing identified five Lichtheimia isolates, two Rhizopus microsporus isolates, two Rhizomucor pusillus isolates, one Cunninghamella bertholletiae isolate, one Mucor fragilis isolate, and one Syncephalastrum racemosum isolate. Five of the 12 (41.7%) isolates were incorrectly identified on the basis of phenotypic identification. DNA sequencing showed that of these five isolates, two were Lichtheimia isolates, one was Mucor isolate, one was Rhizomucor isolate, and one was Rhizopus microspores. All the isolates were identified at the species level by ITS and/or D1/D2 analyses. Phenotypic differentiation and identification of Mucorales is difficult because different Mucorales share similar morphology. Our results indicate that the molecular methods employed in this study are valuable for identifying Mucorales.

A Survey of Active Vibration Isolation Systems for Microgravity Applications

NASA Technical Reports Server (NTRS)

Grodsinsky, Carlos M.; Whorton, Mark S.

2000-01-01

In view of the utility of space vehicles as orbiting science laboratories, the need for vibration isolation systems for acceleration sensitive experiments has gained increasing visibility. To date, three active microgravity vibration isolation systems have successfully been demonstrated in flight. This paper provides a tutorial discussion of the microgravity vibration isolation problem including a description of the acceleration environment of the International Space Station and attenuation requirements as well as a comparison of the dynamics of passive isolation, active rack-level isolation, and active payload-level isolation. This paper also surveys the flight test results of the three demonstrated systems: Suppression of Transient Accelerations By Levitation (STABLE); the Microgravity Vibration Isolation Mount (MIM); and the Active Rack Isolation System (ARIS).

A comparison of surface water natural organic matter in raw filtered water samples, XAD, and reverse osmosis isolates.

PubMed

Maurice, Patricia A; Pullin, Michael J; Cabaniss, Stephen E; Zhou, Qunhui; Namjesnik-Dejanovic, Ksenija; Aiken, George R

2002-05-01

This research compared raw filtered waters (RFWs), XAD resin isolates (XAD-8 and XAD-4), and reverse osmosis (RO) isolates of several surface water samples from McDonalds Branch, a small freshwater fen in the New Jersey Pine Barrens (USA). RO and XAD-8 are two of the most common techniques used to isolate natural organic matter (NOM) for studies of composition and reactivity; therefore, it is important to understand how the isolates differ from bulk (unisolated) samples and from one another. Although, any comparison between the isolation methods needs to consider that XAD-8 is specifically designed to isolate the humic fraction, whereas RO concentrates a broad range of organic matter and is not specific to humics. The comparison included for all samples: weight average molecular weight (Mw), number average molecular weight (Mn), polydispersity (rho), absorbance at 280 nm normalized to moles C (epsilon280) (RFW and isolates); and for isolates only: elemental analysis, % carbon distribution by 13C NMR, and aqueous FTIR spectra. As expected, RO isolation gave higher yield of NOM than XAD-8, but also higher ash content, especially Si and S. Mw decreased in the order: RO > XAD-8 > RFW > XAD-4. The Mw differences of isolates compared with RFW may be due to selective isolation (fractionation), or possibly in the case of RO to condensation or coagulation during isolation. 13C NMR results were roughly similar for the two methods, but the XAD-8 isolate was slightly higher in 'aromatic' C and the RO isolate was slightly higher in heteroaliphatic and carbonyl C. Infrared spectra indicated a higher carboxyl content for the XAD-8 isolates and a higher ester:carboxyl ratio for the RO isolates. The spectroscopic data thus are consistent with selective isolation of more hydrophobic compounds by XAD-8, and also with potential ester hydrolysis during that process, although further study is needed to determine whether ester hydrolysis does indeed occur. Researchers choosing between XAD and RO isolation methods for NOM need to consider first the purpose of the isolation; i.e., whether humic fractionation is desirable. Beyond that, they should consider the C yield and ash content, as well as the potential for alteration of NOM by ester hydrolysis (XAD) or condensation/coagulation (RO). Furthermore, the RO and XAD methods produce different fractions or isolates so that researchers should be careful when comparing the compositions and reactivities of NOM samples isolated by these two different techniques.

A comparison of surface water natural organic matter in raw filtered water samples, XAD, and reverse osmosis isolates

USGS Publications Warehouse

Maurice, P.A.; Pullin, M.J.; Cabaniss, S.E.; Zhou, Q.; Namjesnik-Dejanovic, K.; Aiken, G.R.

2002-01-01

This research compared raw filtered waters (RFWs), XAD resin isolates (XAD-8 and XAD-4), and reverse osmosis (RO) isolates of several surface water samples from McDonalds Branch, a small freshwater fen in the New Jersey Pine Barrens (USA). RO and XAD-8 are two of the most common techniques used to isolate natural organic matter (NOM) for studies of composition and reactivity; therefore, it is important to understand how the isolates differ from bulk (unisolated) samples and from one another. Although, any comparison between the isolation methods needs to consider that XAD-8 is specifically designed to isolate the humic fraction, whereas RO concentrates a broad range of organic matter and is not specific to humics. The comparison included for all samples: weight average molecular weight (Mw), number average molecular weight (Mn), polydispersity (??), absorbance at 280nm normalized to moles C (??280) (RFW and isolates); and for isolates only: elemental analysis, % carbon distribution by 13C NMR, and aqueous FTIR spectra. As expected, RO isolation gave higher yield of NOM than XAD-8, but also higher ash content, especially Si and S. Mw decreased in the order: RO>XAD-8>RFW>XAD-4. The Mw differences of isolates compared with RFW may be due to selective isolation (fractionation), or possibly in the case of RO to condensation or coagulation during isolation. 13C NMR results were roughly similar for the two methods, but the XAD-8 isolate was slightly higher in 'aromatic' C and the RO isolate was slightly higher in heteroaliphatic and carbonyl C. Infrared spectra indicated a higher carboxyl content for the XAD-8 isolates and a higher ester:carboxyl ratio for the RO isolates. The spectroscopic data thus are consistent with selective isolation of more hydrophobic compounds by XAD-8, and also with potential ester hydrolysis during that process, although further study is needed to determine whether ester hydrolysis does indeed occur. Researchers choosing between XAD and RO isolation methods for NOM need to consider first the purpose of the isolation; i.e., whether humic fractionation is desirable. Beyond that, they should consider the C yield and ash content, as well as the potential for alteration of NOM by ester hydrolysis (XAD) or condensation/coagulation (RO). Furthermore, the RO and XAD methods produce different fractions or isolates so that researchers should be careful when comparing the compositions and reactivities of NOM samples isolated by these two different techniques. ?? 2002 Published by Elsevier Science Ltd.

Comparison of CTX-M-14- and CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae isolates from patients with bacteremia.

PubMed

Shin, Juyoun; Kim, Dae Hun; Ko, Kwan Soo

2011-07-01

Recently, CTX-M-15-producing Enterobacteriaceae has disseminated worldwide. To better understand the success of CTX-M-15-type extended-spectrum β-lactamase, we compared the CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae isolates with CTX-M-14-producing E. coli and K. pneumoniae isolates that had been more prevalent before the recent increase of CTX-M-15 in Korea. Eighty-nine CTX-M-producing E. coli bloodstream infection isolates and 33 K. pneumoniae bloodstream infection isolates were collected in 2008 from nine hospitals in Korea. In vitro susceptibility testing and multilocus sequence typing were performed for all isolates. Phylogenetic groupings and distribution of virulence determinants and addiction systems were examined for only E. coli isolates. Among the 89 CTX-M-producing E. coli isolates, 54 isolates (60.7%) contained bla(CTx-M-15) and bla(CTx-M-14) was identified in 31 isolates (34.8%). Among 33 CTX-M-producing K. pneumoniae isolates, bla(CTx-M-14) and bla(CTx-M-15) were identified in 18 (54.5%) and 15 (45.5%) isolates, respectively. While CTX-M-14- and CTX-M-15-producing E. coli isolates displayed similar antimicrobial resistance rates, CTX-M-15-producing K. pneumoniae isolates showed significantly higher resistance rates of ciprofloxacin and piperacillin-tazobactam than CTX-M-14-producing isolates. ST131 and ST405 were the main clones in both CTX-M-14- and CTX-M-15-producing E. coli isolates. Although the frequency of virulence determinants was similar between two E. coli groups, ST131 and ST405 isolates producing CTX-M-15 showed higher frequency of determinants. In addition, CTX-M-15-producing E. coli isolates showed higher prevalence of addiction systems, particularly vagCD. ST405 showed the highest prevalence rates among main E. coli clones. In K. pneumoniae, ST15 and ST11, with high resistance rates, were the main clones of CTX-M-15-producing isolates, but no main clones was found among CTX-M-14-producing isolates because of extreme diversity. Rapid increase of CTX-M-15-producing E. coli isolates was due to certain clone with high frequency of virulence determinants and addiction systems. High antimicrobial resistance rates of CTX-M-15-producing K. pneumoniae isolates may contribute to their increase. Copyright © 2011 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Genomic Comparisons and Shiga Toxin Production among Escherichia coli O157:H7 Isolates from a Day Care Center Outbreak and Sporadic Cases in Southeastern Wisconsin

PubMed Central

Gouveia, S.; Proctor, M. E.; Lee, M.-S.; Luchansky, J. B.; Kaspar, C. W.

1998-01-01

Contour-clamped homogeneous electric field pulsed-field gel electrophoresis (CHEF-PFGE) was used to compare Wisconsin isolates of Escherichia coli O157:H7, including 39 isolates from a 1994 day care center outbreak, 28 isolates from 18 individuals from the surrounding geographic area with sporadic cases occurring during the 3 months before the outbreak, and 3 isolates, collected in 1995, from patients with hemolytic-uremic syndrome (HUS) who were from eastern Wisconsin counties other than those inhabited by the day care center and sporadic-case individuals. The technique of CHEF-PFGE using XbaI identified seven highly related restriction endonuclease digestion profiles (REDPs) (93 to 98% similarity) among the 39 day care center isolates and nine XbaI REDPs (63 to 93% similarity) among the 28 isolates from sporadic-case individuals, including REDP 33, which was exhibited by both day care and sporadic-case isolates. PFGE analyses of sequential E. coli O157:H7 isolates from symptomatic day care center attendees revealed that the REDPs of 25 isolates from eight patients were indistinguishable whereas the REDPs of 2 of 6 isolates from two patients differed slightly (93 to 95% similarity). The REDPs of the three isolates from 1995 HUS patients were 78 to 83% similar, with REDP 26 being exhibited by one HUS-associated isolate and an isolate from one day care attendee who did not develop HUS. The genes for both Shiga toxins I and II (stx1 and stx2, respectively) were detected in all but one isolate (sporadic case), and Shiga toxin production by the day care center isolates was not significantly different from that of the other isolates, including the three HUS-associated isolates. Analyses of E. coli O157:H7 isolates from both the day care center outbreak and sporadic cases by CHEF-PFGE permitted us to define the REDP variability of an outbreak and geographic region and demonstrated that the day care center outbreak and a HUS case in 1995 were caused by E. coli O157:H7 strains endemic to eastern Wisconsin. PMID:9508303

Genetic and pathogenic difference between Streptococcus agalactiae serotype Ia fish and human isolates.

PubMed

Chu, Chishih; Huang, Pei-Yu; Chen, Hung-Ming; Wang, Ying-Hsiang; Tsai, I-An; Lu, Chih-Cheng; Chen, Che-Chun

2016-08-02

Streptococcus agalactiae (GBS) is a common pathogen to infect newborn, woman, the elderly, and immuno-compromised human and fish. 37 fish isolates and 554 human isolates of the GBS in 2007-2012 were investigated in serotypes, antibiotic susceptibility, genetic difference and pathogenicity to tilapia. PCR serotyping determined serotype Ia for all fish GBS isolates and only in 3.2 % (3-4.2 %) human isolates. For fish isolates, all consisted a plasmid less than 6 kb and belonged to ST7 type, which includes mainly pulsotypes I and Ia, with a difference in a deletion at the largest DNA fragment. These fish isolates were susceptible to all antimicrobials tested in 2007 and increased in non-susceptibility to penicillin, and resistance to clindamycin and ceftriaxone in 2011. Differing in pulsotype and lacking plasmid from fish isolates, human serotype Ia isolates were separated into eight pulsotypes II-IX. Main clone ST23 included pulsotypes II and IIa (50 %) and ST483 consisted of pulsotype III. Human serotype Ia isolates were all susceptible to ceftriaxone and penicillin and few were resistant to erythromycin, azithromycin, clindamycin, levofloxacin and moxifloxacine with the resistant rate of 20 % or less. Using tilapia to analyze the pathogenesis, fish isolates could cause more severe symptoms, including hemorrhage of the pectoral fin, hemorrhage of the gill, and viscous black and common scites, and mortality (>95 % for pulsotype I) than the human isolates (<30 %); however, the fish pulostype Ia isolate 912 with deletion caused less symptoms and the lowest mortality (<50 %) than pulsotype I isolates. Genetic, pathogenic, and antimicrobial differences demonstrate diverse origin of human and fish serotype Ia isolates. The pulsotype Ia of fish serotype Ia isolates may be used as vaccine strains to prevent the GBS infection in fish.

Comparison of phenotypic and virulence genes characteristics in human and chicken isolates of Proteus mirabilis.

PubMed

Barbour, Elie K; Hajj, Zahi G; Hamadeh, Shadi; Shaib, Houssam A; Farran, Mohamad T; Araj, George; Faroon, Obaid; Barbour, Kamil E; Jirjis, Faris; Azhar, Esam; Kumosani, Taha; Harakeh, Steve

2012-10-01

The objective of this work is to compare the phenotypic and virulence genes characteristics in human and chicken isolates of Proteus mirabilis. The bacterial examination of 50 livers of individual broilers, marketed by four major outlets, revealed a high recovery of P. mirabilis (66%), and a low recovery frequency of Salmonella spp. (4%), Serratia odorifera (2%), Citrobacter brakii (2%), and Providencia stuartii (2%). The phenotypic biochemical characterization of the recovered 33 chicken isolates of P. mirabilis were compared to 30 human isolates (23 urinary and six respiratory isolates). The comparison revealed significant differences in the presence of gelatinase enzyme (100% presence in chicken isolates versus 91.3 and 83.3% presence in human urinary and respiratory isolates, respectively, P,0.05). The H(2)S production occurred in 100% of chicken isolates versus 95.6 and 66.7% presence in human urinary and respiratory isolates, respectively, P,0.05). The other 17 biochemical characteristics did not differ significantly among the three groups of isolates (P.0.05). Two virulence genes, the mrpA and FliL, were having a typical 100% presence in randomly selected isolates of P. mirabilis recovered from chicken livers (N510) versus isolates recovered from urinary (N55) and respiratory specimens of humans (N55) (P.0.05). The average percentage similarity of mrpA gene nucleotide sequence of poultry isolates to human urinary and respiratory isolates was 93.2 and 97.5-%, respectively. The high similarity in phenotypic characteristics, associated with typical frequency of presence of two virulence genes, and high similarity in sequences of mrpA gene among poultry versus human P. mirabilis isolates justifies future investigations targeting the evaluation of adaptable pathogenicity of avian Proteus mirabilis isolates to mammalian hosts.

Characterization of antimicrobial resistance in Salmonella enterica strains isolated from Brazilian poultry production.

PubMed

Mattiello, Samara P; Drescher, Guilherme; Barth, Valdir C; Ferreira, Carlos A S; Oliveira, Sílvia D

2015-11-01

Antimicrobial resistance profiles and presence of resistance determinants and integrons were evaluated in Salmonella enterica strains from Brazilian poultry. The analysis of 203 isolates showed that those from the poultry environment (88 isolates) were significantly more resistant to antimicrobials than isolates from other sources, particularly those isolated from poultry by-product meal (106 isolates). Thirty-seven isolates were resistant to at least three antimicrobial classes. Class 1 integrons were detected in 26 isolates, and the analysis of the variable region between the 5' conserved segment (CS) and 3' CS of each class 1 integron-positive isolate showed that 13 contained a typical 3' CS and 14 contained an atypical 3' CS. One Salmonella Senftenberg isolate harbored two class 1 integrons, showing both typical and atypical 3' CSs. The highest percentage of resistance was found to sulfonamides, and sul genes were detected in the majority of the resistant isolates. Aminoglycoside resistance was detected in 50 isolates, and aadA and aadB were present in 28 and 32 isolates, respectively. In addition, strA and strB were detected in 78.1 and 65.6% isolates resistant to streptomycin, respectively. Twenty-one isolates presented reduced susceptibility to β-lactams and harbored bla(TEM), bla(CMY), and/or bla(CTX-M). Forty isolates showed reduced susceptibility to tetracycline, and most presented tet genes. These results highlight the importance of the environment as a reservoir of resistant Salmonella, which may enable the persistence of resistance determinants in the poultry production chain, contributing, therefore, to the debate regarding the impacts that antimicrobial use in animal production may exert in human health.

Characterisation of clinically isolated Streptococcus pyogenes from balanoposthitis patients, with special emphasis on emm89 isolates.

PubMed

Hasegawa, Tadao; Hata, Nanako; Matsui, Hideyuki; Isaka, Masanori; Tatsuno, Ichiro

2017-04-01

Streptococcus pyogenes causes a variety of diseases, such as pharyngitis and toxic shock syndrome. In addition, this bacterium is a causative agent of balanoposthitis. To reveal the bacteriological characteristics of the isolates from balanoposthitis patients, we analysed 47 isolates. In addition, novel clade genotype emm89 S. pyogenes isolates have been reported to be spreading worldwide recently. Hence, we further analysed eight emm89 isolates. A drug susceptibility experiment was performed and emm types were determined. More detailed experiments, such as PCR analysis for the presence of virulence-associated genes and MLST analysis, were performed especially using emm89 isolates. All isolates were sensitive to ampicillin, but 34 % of the isolates were resistant to at least one antibiotic. The emm types of the isolates varied, with emm89 and emm11 being the most prevalent, but the emm1 type was not detected. The analysis of emm89 isolates revealed that drug susceptibilities varied. All isolates were negative for the hasABC gene and produced active NADase that are characteristics of novel clade genotype emm89 S. pyogenes. MLST analysis demonstrated that six isolates were of the ST101 type, the most predominant type reported thus far, but two isolates were of the ST646 type. According to the PCR analysis used to determine the presence of streptococcal pyrogenic exotoxin-related genes, the six ST101 isolates were further classified into four groups. These results suggest that balanoposthitis is caused by a variety of types of S. pyogenes, with novel clade genotype emm89 isolates playing a role in balanoposthitis infections in Japan.

Analysis of the Listeria monocytogenes Population Structure among Isolates from 1931 to 2015 in Australia

PubMed Central

Jennison, Amy V.; Masson, Jesse J.; Fang, Ning-Xia; Graham, Rikki M.; Bradbury, Mark I.; Fegan, Narelle; Gobius, Kari S.; Graham, Trudy M.; Guglielmino, Christine J.; Brown, Janelle L.; Fox, Edward M.

2017-01-01

Listeriosis remains among the most important bacterial illnesses, with a high associated mortality rate. Efforts to control listeriosis require detailed knowledge of the epidemiology of the disease itself, and its etiological bacterium, Listeria monocytogenes. In this study we provide an in-depth analysis of the epidemiology of 224 L. monocytogenes isolates from Australian clinical and non-clinical sources. Non-human sources included meat, dairy, seafood, fruit, and vegetables, along with animal and environmental isolates. Serotyping, Multi-Locus Sequence Typing, and analysis of inlA gene sequence were performed. Serogroups IIA, IIB, and IVB comprised 94% of all isolates, with IVB over-represented among clinical isolates. Serogroup IIA was the most common among dairy and meat isolates. Lineage I isolates were most common among clinical isolates, and 52% of clinical isolates belonged to ST1. Overall 39 STs were identified in this study, with ST1 and ST3 containing the largest numbers of L. monocytogenes isolates. These STs comprised 40% of the total isolates (n = 90), and both harbored isolates from clinical and non-clinical sources. ST204 was the third most common ST. The high prevalence of this group among L. monocytogenes populations has not been reported outside Australia. Twenty-seven percent of the STs in this study contained exclusively clinical isolates. Analysis of the virulence protein InlA among isolates in this study identified a truncated form of the protein among isolates from ST121 and ST325. The ST325 group contained a previously unreported novel mutation leading to production of a 93 amino acid protein. This study provides insights in the population structure of L. monocytogenes isolated in Australia, which will contribute to public health knowledge relating to this important human pathogen. PMID:28428781

Isolation and Biochemical Fingerprinting of Vancomycin-Resistant Enterococcus faecium From Meat, Chicken and Cheese.

PubMed

Talebi, Malihe; Sadeghi, Javad; Rahimi, Fateh; Pourshafie, Mohammad Reza

2015-04-01

Vancomycin-resistant enterococci (VRE) are important nosocomial pathogens and food chain has been considered as an assumed source for dissemination of VRE to human. The presence of VRE isolates from food samples and typing of these isolates with Phene plate, a biochemical fingerprinting method, were investigated. Thirty samples of meat, chicken and cheese were analyzed for VRE during 2010. Antibiotic susceptibility tests and minimum inhibitory concentration (MIC) were also examined. VRE isolates were typed with the Phene plate system (PhPlate), a biochemical fingerprinting method. A total of 70 VRE isolates were obtained and identified as Enterococcus faecium by species-specific PCR. All the isolates carried vanA, while none of them harbored vanB. The VRE isolates included 35, 27, and 8 isolates from meat, chicken and cheese, respectively. Typing with the PhPlate revealed a diversity index of 0.78 for E. faecium, containing 10 common and four single types. The results of antibiotic susceptibility and MIC tests showed an increased resistance to ciprofloxacin, erythromycin, ampicillin and gentamicin, to which, 100%, 100%, 100%, and 95% of VRE isolates were resistant, respectively. Only 5% of the isolates were resistant to chloramphenicol and the MIC of the isolates for vancomycin and teicoplanin was ≥ 256 µg/mL and for gentamicin-resistant isolates it was 1024 µg/mL. Conventional and molecular identification tests exhibited that all the isolates were E. faecium carrying vanA. None of the isolates harbored vanB. The results showed that enterococci are common contaminants in food. Indeed, this study indicates a high prevalence of multidrug-resistant enterococci in food of animal origin in Iran. Isolating some persisting enterococcal isolates revealed that continuous surveillance of antimicrobial resistance in enterococci from food is essential.

A single clone of Acinetobacter baumannii, ST22, is responsible for high antimicrobial resistance rates of Acinetobacter spp. isolates that cause bacteremia and urinary tract infections in Korea.

PubMed

Park, Young Kyoung; Lee, Gyu Hong; Baek, Jin Yang; Chung, Doo Ryeon; Peck, Kyong Ran; Song, Jae-Hoon; Ko, Kwan Soo

2010-06-01

We investigated the characteristics of a total of 96 Acinetobacter spp. isolates that were shown to cause bacteremia and urinary tract infections (UTIs) from 10 university hospitals located in various regions of Korea from November 2006 to August 2007. The antimicrobial susceptibilities of these isolates were determined using a broth microdilution method, and the species were identified using molecular identification. In addition, we performed multilocus sequence typing for Acinetobacter baumannii subgroup A isolates. A. baumannii subgroup A was the most prevalent in patients with both bacteremia (32 isolates, 53.3%) and UTIs (20 isolates, 55.6%), followed by Acinetobacter genomic species 13TU (15.0% and 27.8% in bacteremia and UTIs, respectively). A. baumannii subgroup B and Acinetobacter junii were found exclusively in isolates causing bacteremia (seven and five isolates, respectively). Among 96 Acinetobacter spp. isolates, 19.8% were resistant to imipenem and 25.0% were resistant to meropenem. Most carbapenem-resistant A. baumannii isolates contained PER or oxacillinase-23-like enzymes (65.2% and 78.3%, respectively). In addition, 13.5% were resistant to polymyxin B and 17.7% were resistant to colistin. A. baumannii subgroup A isolates (52 isolates, 54.2%) showed higher resistance rates to most antimicrobial agents than other species, but not to colistin. Among A. baumannii subgroup A isolates, ST22 was the most prevalent genotype (33 isolates, 63.5%) and showed higher resistance rates to all antimicrobial agents than the other genotypes. In addition, four out of five polymyxin-resistant A. baumannii group A isolates belonged to ST22. Thus, dissemination of the main clone of A. baumannii, ST22, may contribute to the high resistance rates of Acinetobacter isolates to antimicrobials, including carbapenems, in Korea.

Genetic Attributes of E. coli Isolates from Chlorinated Drinking Water

PubMed Central

Blyton, Michaela D. J.; Gordon, David M.

2017-01-01

Escherichia coli, is intimately associated with both human health and water sanitation. E. coli isolates from water can either be (i) host associated commensals, indicating recent faecal contamination; (ii) diarrheal pathogens or (iii) extra-intestinal pathogens that pose a direct health risk; or (iv) free-living. In this study we genetically characterised 28 E. coli isolates obtained from treated drinking water in south eastern Australia to ascertain their likely source. We used full genome sequencing to assign the isolates to their phylogenetic group and multi-locus sequence type. The isolates were also screened in silico for several virulence genes and genes involved in acquired antibiotic resistance. The genetic characteristics of the isolates indicated that four isolates were likely human pathogens. However, these isolates were not detected in sufficient numbers to present a health risk to the public. An additional isolate was a human associated strain. Nine isolates were water associated free-living strains that were unlikely to pose a health risk. Only 14% of the isolates belonged to the host associated phylogenetic group (B2) and only a single isolate had any antibiotic resistance genes. This suggests that the primary source of the drinking water E. coli isolates may not have been recent human faecal contamination. PMID:28107364

Characterization of Leishmania isolates from Nepalese patients with visceral leishmaniasis.

PubMed

Pandey, Kishor; Yanagi, Testuo; Pandey, Basu Dev; Mallik, Arun Kumar; Sherchand, Jeevan Bahadur; Kanbara, Hiroji

2007-05-01

In Nepal, visceral leishmaniasis (VL) is endemic in 13 districts of the central and eastern regions. A total of 166 bone-marrow aspirates were obtained from patients with suspected VL. Ninety-seven were identified as positive by microscopy, and 29 of those were successfully isolated and cultured. We characterized these isolates by molecular analysis and by their ability to infect mice. PCR-restriction fragment length polymorphism analysis of the mini-exon and the cysteine proteinase b gene showed that all isolates were Leishmania donovani, and the restriction pattern of the Nepalese isolates corresponded to the standard Indian strain of L. donovani but differed from that of the Kenyan strain. The single-strand conformation polymorphism analysis of ribosomal internal transcribed spacer showed no genetic heterogeneity within Nepalese isolates. Intraperitoneal inoculation with the promastigotes of all isolates resulted in amastigote proliferation in the spleen of 20 nude mice, of which ten isolates were highly infective, and ten were moderately infective, including one BALB/c mouse. Of the 20 amastigotes isolated from the spleen of nude mice, only the ten highly infective isolates infected BALB/c mice, of which, two isolates were considered to have low infectivity, three isolates were considered to be moderately infective, and five isolates were considered to be highly infective.

Occurrence, Genotyping, and Antibiotic Susceptibility of Cronobacter spp. in Drinking Water and Food Samples from Northeast China.

PubMed

Fei, Peng; Jiang, Yichao; Gong, Shaoying; Li, Ran; Jiang, Yan; Yuan, Xiujuan; Wang, Ziyuan; Kang, Huaibin; Ali, Md Aslam

2018-02-23

Cronobacter species (formerly Enterobacter sakazakii) are emerging opportunistic bacterial pathogens that can infect both infants and adults. This study was conducted to isolate and genotype diverse Cronobacter species from drinking water, chilled fresh pork, powdered infant formula, instant noodles, cookies, fruits, vegetables, and dishes in Northeast China and to evaluate the antibiotic resistance and susceptibility of the isolates. Thirty-four Cronobacter strains were isolated and identified: 21 C. sakazakii isolates (61.8%), 10 C. malonaticus isolates (29.4%), 2 C. dublinensis isolates (5.9%), and 1 C. turicensis isolate (2.9%). These isolates were further divided into 15 sequence types (STs) by multilocus sequence typing. C. sakazakii ST4 (10 isolates, 29.4%), ST1 (3 isolates, 8.8%), and ST8 (3 isolates, 8.8%) and C. malonaticus ST7 (four isolates, 11.8%) were dominant. Antibiotic susceptibility testing indicated that all 34 Cronobacter isolates were susceptible to ampicillin-sulbactam, cefotaxime, ciprofloxacin, gentamicin, meropenem, tetracycline, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole, 88.2% were susceptible to chloramphenicol, and 67.6% were resistant to cephalothin. The results of this study enhance knowledge about genotyping and antibiotic resistance of these Cronobacter species and could be used to prevent potential hazards caused by these strains in drinking water and various food products.

Social Isolation, Depression, and Psychological Distress Among Older Adults.

PubMed

Taylor, Harry Owen; Taylor, Robert Joseph; Nguyen, Ann W; Chatters, Linda

2018-02-01

To investigate the impact of objective and subjective social isolation from extended family members and friends on depressive symptoms and psychological distress among a national sample of older adults. Data for older adults (55 years and above) from the National Survey of American Life ( N = 1,439) were used to assess level of objective social isolation and subjective social isolation and to test regression models examining their impact on depressive symptoms (Center for Epidemiologic Studies Depression [CES-D] Scale) and psychological distress (Kessler 6 [K6] Scale). The majority of respondents were not socially isolated from family or friends; 5% were objectively isolated from family and friends, and less than 1% were subjectively isolated from family and friends. Regression analyses using both social isolation measures indicated that objective social isolation was unrelated to depressive symptoms and psychological distress. However, subjective social isolation from both family and friends and from friends only was associated with more depressive symptoms, and subjective social isolation from friends only was associated with higher levels of psychological distress. Assessments of social isolation among older populations should account for both subjective and objective dimensions, as well as both family and friend social networks. Social isolation from friends is an important, but understudied, issue that has significant consequences for older adult mental health.

Genetic Attributes of E. coli Isolates from Chlorinated Drinking Water.

PubMed

Blyton, Michaela D J; Gordon, David M

2017-01-01

Escherichia coli, is intimately associated with both human health and water sanitation. E. coli isolates from water can either be (i) host associated commensals, indicating recent faecal contamination; (ii) diarrheal pathogens or (iii) extra-intestinal pathogens that pose a direct health risk; or (iv) free-living. In this study we genetically characterised 28 E. coli isolates obtained from treated drinking water in south eastern Australia to ascertain their likely source. We used full genome sequencing to assign the isolates to their phylogenetic group and multi-locus sequence type. The isolates were also screened in silico for several virulence genes and genes involved in acquired antibiotic resistance. The genetic characteristics of the isolates indicated that four isolates were likely human pathogens. However, these isolates were not detected in sufficient numbers to present a health risk to the public. An additional isolate was a human associated strain. Nine isolates were water associated free-living strains that were unlikely to pose a health risk. Only 14% of the isolates belonged to the host associated phylogenetic group (B2) and only a single isolate had any antibiotic resistance genes. This suggests that the primary source of the drinking water E. coli isolates may not have been recent human faecal contamination.

Molecular analysis of Leptospira spp. isolated from humans by restriction fragment length polymorphism, real-time PCR and pulsed-field gel electrophoresis.

PubMed

Turk, Nenad; Milas, Zoran; Mojcec, Vesna; Ruzic-Sabljic, Eva; Staresina, Vilim; Stritof, Zrinka; Habus, Josipa; Postic, Daniele

2009-11-01

A total of 17 Leptospira clinical strains isolated from humans in Croatia were serologically and genetically analysed. For serovar identification, the microscopic agglutination test (MAT) and pulsed-field gel electrophoresis (PFGE) were used. To identify isolates on genomic species level, PCR-based restriction fragment length polymorphism (RFLP) and real-time PCR were performed. MAT revealed the following serogroup affinities: Grippotyphosa (seven isolates), Icterohaemorrhagiae (eight isolates) and Javanica (two isolates). RFLP of PCR products from a 331-bp-long fragment of rrs (16S rRNA gene) digested with endonucleases MnlI and DdeI and real-time PCR revealed three Leptospira genomic species. Grippotyphosa isolates belonged to Leptospira kirschneri, Icterohaemorrhagiae isolates to Leptospira interrogans and Javanica isolates to Leptospira borgpetersenii. Genomic DNA from 17 leptospiral isolates was digested with NotI and SgrAI restriction enzymes and analysed by PFGE. Results showed that seven isolates have the same binding pattern to serovar Grippotyphosa, eight isolates to serovar Icterohaemorrhagiae and two isolates to serovar Poi. Results demonstrate the diversity of leptospires circulating in Croatia. We point out the usefulness of a combination of PFGE, RFLP and real-time PCR as appropriate molecular methods in molecular analysis of leptospires.

Bean common mosaic virus isolates causing different symptoms in asparagus bean in China differ greatly in the 5'-parts of their genomes.

PubMed

Zheng, Hongying; Chen, Jiong; Chen, Jianping; Adams, Michael J; Hou, Mingsheng

2002-06-01

Potyvirus isolates from asparagus bean ( Vigna sesquipedalis) plants in Zhejiang province, China, caused either rugose and vein banding mosaic symptoms (isolate R) or severe yellowing (isolate Y) in this host, but were otherwise similar in host range. Both isolates were completely sequenced and shown to be isolates of Bean common mosaic virus (BCMV). The complete sequences were 9992 (R) or 10062 (Y) nucleotides long and shared 91.7% identical nucleotides (93.2% identical amino acids) in their genomes and were more distantly related to the BCMV-Peanut stripe virus sequence (PStV). The isolates were much less similar to one another in the 5'-UTR and the N-terminal region of the P1 protein. In the P1, isolate Y was closer to PStV (76.1% identical amino acids) than to isolate R (64.8%). Phylogenetic analyses of the coat protein region showed that the new isolates grouped with other isolates from Vigna spp., forming the blackeye cowpea mosaic strain subgroup of BCMV with 94-98% nucleotides (96-99% amino acids) identical to one another and about 90% identity to other BCMV isolates. Other significant subgroupings amongst published BCMV isolates were detected.

Antibiotic resistance phenotypes and virulence-associated genes in Escherichia coli isolated from animals and animal food products in Tunisia.

PubMed

Badi, Souhir; Cremonesi, Paola; Abbassi, Mohamed Salah; Ibrahim, Chourouk; Snoussi, Majdi; Bignoli, Giulia; Luini, Mario; Castiglioni, Bianca; Hassen, Abdennaceur

2018-05-01

Livestock and food products of animal origin constitute important reservoirs of intestinal and extraintestinal pathogenic Escherichia coli including antibiotic-resistant E. coli isolates. To assess potential risks to public health related to E. coli strains of animal origin in Tunisia, 65 E. coli isolates recovered from healthy animals and food products of animal origin were studied. Antimicrobial susceptibility was determined according to CLSI guidelines and genes encoding antibiotic resistance as well as virulence factors were investigated by PCR. High rates of antibiotic resistance were observed to kanamycin (78.4%), gentamicin (75.3%) and streptomycin (75.3%, encoded by strA-strB (7 isolates)), amoxicillin (64.6%), amoxicillin/clavulanic acid (60%), tetracycline (44.6%; tetA (8 isolates) and tetB (7 isolates)), nalidixic acid (27.6%, qnrS (3 isolates), qnrB (2 isolates) and qnrA (one isolate)) and sulfonamides (36.9%; sul1 (1 isolate), sul2 (4 isolates), and sul3 (1 isolate)). Virulotypes classified some isolates as STEC (3%), MNEC (1.5%) and atypical EPEC (1.5%). This study demonstrated high rates of antimicrobial resistance and the presence of some pathogenic pathovars from animal origins that are a cause of concern for public health.

Child physical abuse and self-perceived social isolation among adolescents.

PubMed

Elliott, Gregory C; Cunningham, Susan M; Linder, Meadow; Colangelo, Melissa; Gross, Michelle

2005-12-01

This research examines the connection between physical abuse and social isolation. Using data from the National Youth Survey, a measure of self-perceived social isolation was constructed indicating the extent to which respondents feel detached from their friends and from school. Those who had experienced violence were predicted to be more isolated than those who had not. Results strongly supported the hypothesis, controlling for theoretically relevant variables. Explanation is provided in terms of damage to attachment skills, social competence, and self-esteem concomitant to being a victim of abuse. Males were more socially isolated than females, and Hispanics more than Whites. Children with involved parents were less socially isolated; those whose parents experienced normlessness were more isolated. Children who recently experienced a stressful event or were from riskier neighborhoods were more isolated. The number of children in the family was positively related to isolation. Social isolation decreases between seventh and eighth grades.

Vapor-barrier Vacuum Isolation System

NASA Technical Reports Server (NTRS)

Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

2014-01-01

A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

Epidemiology of Extended-Spectrum β-Lactamase-Producing Enterobacter Isolates in a Spanish Hospital during a 12-Year Period

PubMed Central

Cantón, Rafael; Oliver, Antonio; Coque, Teresa M.; Varela, María del Carmen; Pérez-Díaz, José Claudio; Baquero, Fernando

2002-01-01

Fifteen Enterobacter clinical isolates (11 Enterobacter cloacae isolates, 3 Enterobacter aerogenes isolates, and 1 Enterobacter gergoviae isolate), representing 0.4% of all Enterobacter isolates recovered in our hospital from 1989 to 2000, were suspected of harboring an extended-spectrum β-lactamase (ESBL). These isolates were recovered from 14 different patients. ESBLs were transferred by conjugation into an Escherichia coli recipient strain. Pulsed-field gel electrophoresis (PFGE) revealed a single clone of E. aerogenes and six different clones of E. cloacae. Four of these E. cloacae clonal types were represented by only one isolate each, but the other two were represented by three and four isolates, respectively. Isoelectric focusing, susceptibility phenotyping, PCR analysis, and sequencing demonstrated the presence of three different ESBLs. The most frequent was the recently characterized CTX-M-10 ESBL, which was found in the E. gergoviae isolate and in all but one of the E. cloacae isolates. The remaining E. cloacae isolate harbored a TEM-27 ESBL, and the three E. aerogenes isolates harbored a TEM-24 ESBL. PFGE revealed that our E. aerogenes strain was indistinguishable from the French TEM-24-producing E. aerogenes endemic clone. Although a low prevalence of ESBL-producing Enterobacter isolates was found in our institution over a 12-year period, a diversity of nonepidemic E. cloacae clones was detected, as was the persistence of the CTX-M-10 β-lactamase. The presence of the TEM-24-producing E. aerogenes French clone in our institution also demonstrates the intercountry dissemination of ESBL-producing isolates. PMID:11923338

Multicenter Study Evaluating the Vitek MS System for Identification of Medically Important Yeasts

PubMed Central

Westblade, Lars F.; Jennemann, Rebecca; Branda, John A.; Bythrow, Maureen; Ferraro, Mary Jane; Garner, Omai B.; Ginocchio, Christine C.; Lewinski, Michael A.; Manji, Ryhana; Mochon, A. Brian; Procop, Gary W.; Richter, Sandra S.; Rychert, Jenna A.; Sercia, Linda

2013-01-01

The optimal management of fungal infections is correlated with timely organism identification. Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry (MS) is revolutionizing the identification of yeasts isolated from clinical specimens. We present a multicenter study assessing the performance of the Vitek MS system (bioMérieux) in identifying medically important yeasts. A collection of 852 isolates was tested, including 20 Candida species (626 isolates, including 58 C. albicans, 62 C. glabrata, and 53 C. krusei isolates), 35 Cryptococcus neoformans isolates, and 191 other clinically relevant yeast isolates; in total, 31 different species were evaluated. Isolates were directly applied to a target plate, followed by a formic acid overlay. Mass spectra were acquired using the Vitek MS system and were analyzed using the Vitek MS v2.0 database. The gold standard for identification was sequence analysis of the D2 region of the 26S rRNA gene. In total, 823 isolates (96.6%) were identified to the genus level and 819 isolates (96.1%) were identified to the species level. Twenty-four isolates (2.8%) were not identified, and five isolates (0.6%) were misidentified. Misidentified isolates included one isolate of C. albicans (n = 58) identified as Candida dubliniensis, one isolate of Candida parapsilosis (n = 73) identified as Candida pelliculosa, and three isolates of Geotrichum klebahnii (n = 6) identified as Geotrichum candidum. The identification of clinically relevant yeasts using MS is superior to the phenotypic identification systems currently employed in clinical microbiology laboratories. PMID:23658267

Diversity and Fermentation Products of Xylose-Utilizing Yeasts Isolated from Buffalo Feces in Thailand

PubMed Central

Lorliam, Wanlapa; Akaracharanya, Ancharida; Suzuki, Motofumi; Ohkuma, Moriya; Tanasupawat, Somboon

2013-01-01

Twenty-eight xylose-utilizing yeast strains were isolated by enrichment culture from 11 samples of feces from the rectum of Murrah buffalo and Swamp buffalo in Thailand. On the basis of their morphological and biochemical characteristics, including sequence analysis of the D1/D2 region of the large-subunit ribosomal RNA gene (LSU rDNA), they were identified as Candida tropicalis (designated as Group I, 11 isolates), Candida parasilosis (Group II, 2 isolates), Candida mengyuniae (Group III, 2 isolates), Sporopachydermia lactativora (Group IV, 2 isolates), Geotrichum sp. (Group V, 5 isolates) and Trichosporon asahii (Group VI, 6 isolates). All isolates utilized xylose as the sole carbon source but 27 isolates could ferment xylose to ethanol (0.006–0.602 g L−1) and 21 isolates could ferment xylose to xylitol (0.19–22.84 g L−1). Candida tropicalis isolates produced the highest yield of xylitol (74.80%). Their ability to convert xylose to xylitol and ethanol ranged from 15.06 g L−1 to 22.84 g L−1 xylitol and 0.110 g L−1 to 0.602 g L−1 ethanol, respectively. PMID:24005843

Characterization of Salmonella Typhimurium isolates associated with septicemia in swine.

PubMed

Bergeron, Nadia; Corriveau, Jonathan; Letellier, Ann; Daigle, France; Quessy, Sylvain

2010-01-01

Salmonella Typhimurium is frequently isolated from pigs and may also cause enteric disease in humans. In this study, 33 isolates of S. Typhimurium associated with septicemia in swine (CS) were compared to 33 isolates recovered from healthy animals at slaughter (WCS). The isolates were characterized using phenotyping and genotyping methods. For each isolate, the phage type, antimicrobial resistance, and pulsed-field gel electrophoresis (PFGE) DNA profiles were determined. In addition, the protein profiles of each isolate grown in different conditions were studied by Coomassie Blue-stained sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblot. Various phage types were identified. The phage type PT 104 represented 36.4% of all isolates from septicemic pigs. Resistance to as many as 12 antimicrobial agents, including some natural resistances, was found in isolates from CS and WCS. Many genetic profiles were identified among the PT 104 phage types. Although it was not possible to associate one particular protein with septicemic isolates, several highly immunogenic proteins, present in all virulent isolates and in most isolates from clinically healthy animals, were identified. These results indicated that strains associated with septicemia belong to various genetic lineages that can also be recovered from asymptomatic animals at the time of slaughter.

Protein distribution in lupin protein isolates from Lupinus angustifolius L. prepared by various isolation techniques.

PubMed

Muranyi, Isabel S; Volke, Daniela; Hoffmann, Ralf; Eisner, Peter; Herfellner, Thomas; Brunnbauer, Markus; Koehler, Peter; Schweiggert-Weisz, Ute

2016-09-15

Differences in the protein distribution of various protein isolates from Lupinus angustifolius L. Vitabor were identified as affected by the isolation procedure (alkaline and/or salt-induced extraction followed by isoelectric and/or dilutive precipitation). Protein isolates extracted in alkaline solution showed higher protein yields (26.4-31.7%) compared to salt-induced extraction (19.8-30.0%) or combined alkaline and salt-induced extraction (23.3-25.6%). Chemical variations among the protein isolates especially occurred within the albumins. Protein isolates precipitated isoelectrically showed the highest contents, whereas protein isolates precipitated by dilutive showed the lowest contents of conglutin δ. Furthermore, the alkaline subunits of conglutin α and conglutin γ decreased during alkaline extraction compared to salt-induced extraction. A decrease in protein-bound polar and basic amino acids was shown after protein isolation. In contrast, the amounts of nonpolar, aliphatic, aromatic, hydroxylated and sulfur-rich amino acids were higher in the lupin protein isolates compared to the lupin flakes. However, the functional side chains could not be related to the specific molecular arrangements of the protein isolates, as a similar amino acid composition was found among the protein isolates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sequence diversity of wheat mosaic virus isolates.

PubMed

Stewart, Lucy R

2016-02-02

Wheat mosaic virus (WMoV), transmitted by eriophyid wheat curl mites (Aceria tosichella) is the causal agent of High Plains disease in wheat and maize. WMoV and other members of the genus Emaravirus evaded thorough molecular characterization for many years due to the experimental challenges of mite transmission and manipulating multisegmented negative sense RNA genomes. Recently, the complete genome sequence of a Nebraska isolate of WMoV revealed eight segments, plus a variant sequence of the nucleocapsid protein-encoding segment. Here, near-complete and partial consensus sequences of five more WMoV isolates are reported and compared to the Nebraska isolate: an Ohio maize isolate (GG1), a Kansas barley isolate (KS7), and three Ohio wheat isolates (H1, K1, W1). Results show two distinct groups of WMoV isolates: Ohio wheat isolate RNA segments had 84% or lower nucleotide sequence identity to the NE isolate, whereas GG1 and KS7 had 98% or higher nucleotide sequence identity to the NE isolate. Knowledge of the sequence variability of WMoV isolates is a step toward understanding virus biology, and potentially explaining observed biological variation. Published by Elsevier B.V.

Antimicrobial Resistance and Molecular Investigation of H2S-Negative Salmonella enterica subsp. enterica serovar Choleraesuis Isolates in China.

PubMed

Xie, Jing; Yi, Shengjie; Zhu, Jiangong; Li, Peng; Liang, Beibei; Li, Hao; Yang, Xiaoxia; Wang, Ligui; Hao, Rongzhang; Jia, Leili; Wu, Zhihao; Qiu, Shaofu; Song, Hongbin

2015-01-01

Salmonella enterica subsp. enterica serovar Choleraesuis is a highly invasive pathogen of swine that frequently causes serious outbreaks, in particular in Asia, and can also cause severe invasive disease in humans. In this study, 21 S. Choleraesuis isolates, detected from 21 patients with diarrhea in China between 2010 and 2011, were found to include 19 H2S-negative S. Choleraesuis isolates and two H2S-positive isolates. This is the first report of H2S-negative S. Choleraesuis isolated from humans. The majority of H2S-negative isolates exhibited high resistance to ampicillin, chloramphenicol, gentamicin, tetracycline, ticarcillin, and trimethoprim-sulfamethoxazole, but only six isolates were resistant to norfloxacin. In contrast, all of the isolates were sensitive to cephalosporins. Fifteen isolates were found to be multidrug resistant. In norfloxacin-resistant isolates, we detected mutations in the gyrA and parC genes and identified two new mutations in the parC gene. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and clustered regularly interspaced short palindromic repeat (CRISPR) analysis were employed to investigate the genetic relatedness of H2S-negative and H2S-positive S. Choleraesuis isolates. PFGE revealed two groups, with all 19 H2S-negative S. Choleraesuis isolates belonging to Group I and H2S-positive isolates belonging to Group II. By MLST analysis, the H2S-negative isolates were all found to belong to ST68 and H2S-positive isolates belong to ST145. By CRISPR analysis, no significant differences in CRISPR 1 were detected; however, one H2S-negative isolate was found to contain three new spacers in CRISPR 2. All 19 H2S-negative isolates also possessed a frame-shift mutation at position 760 of phsA gene compared with H2S-positive isolates, which may be responsible for the H2S-negative phenotype. Moreover, the 19 H2S-negative isolates have similar PFGE patterns and same mutation site in the phsA gene, these results indicated that these H2S-negative isolates may have been prevalent in China. These findings suggested that surveillance should be increased of H2S-negative S. Choleraesuis in China.

Antimicrobial Resistance and Molecular Investigation of H2S-Negative Salmonella enterica subsp. enterica serovar Choleraesuis Isolates in China

PubMed Central

Li, Peng; Liang, Beibei; Li, Hao; Yang, Xiaoxia; Wang, Ligui; Hao, Rongzhang; Jia, Leili; Wu, Zhihao; Qiu, Shaofu; Song, Hongbin

2015-01-01

Salmonella enterica subsp. enterica serovar Choleraesuis is a highly invasive pathogen of swine that frequently causes serious outbreaks, in particular in Asia, and can also cause severe invasive disease in humans. In this study, 21 S. Choleraesuis isolates, detected from 21 patients with diarrhea in China between 2010 and 2011, were found to include 19 H2S-negative S. Choleraesuis isolates and two H2S-positive isolates. This is the first report of H2S-negative S. Choleraesuis isolated from humans. The majority of H2S-negative isolates exhibited high resistance to ampicillin, chloramphenicol, gentamicin, tetracycline, ticarcillin, and trimethoprim-sulfamethoxazole, but only six isolates were resistant to norfloxacin. In contrast, all of the isolates were sensitive to cephalosporins. Fifteen isolates were found to be multidrug resistant. In norfloxacin-resistant isolates, we detected mutations in the gyrA and parC genes and identified two new mutations in the parC gene. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and clustered regularly interspaced short palindromic repeat (CRISPR) analysis were employed to investigate the genetic relatedness of H2S-negative and H2S-positive S. Choleraesuis isolates. PFGE revealed two groups, with all 19 H2S-negative S. Choleraesuis isolates belonging to Group I and H2S-positive isolates belonging to Group II. By MLST analysis, the H2S-negative isolates were all found to belong to ST68 and H2S-positive isolates belong to ST145. By CRISPR analysis, no significant differences in CRISPR 1 were detected; however, one H2S-negative isolate was found to contain three new spacers in CRISPR 2. All 19 H2S-negative isolates also possessed a frame-shift mutation at position 760 of phsA gene compared with H2S-positive isolates, which may be responsible for the H2S-negative phenotype. Moreover, the 19 H2S-negative isolates have similar PFGE patterns and same mutation site in the phsA gene, these results indicated that these H2S-negative isolates may have been prevalent in China. These findings suggested that surveillance should be increased of H2S-negative S. Choleraesuis in China. PMID:26431037

Isolation and molecular characterization of Salmonella enterica serovar Enteritidis from poultry house and clinical samples during 2010.

PubMed

Mezal, Ezat H; Sabol, Ashley; Khan, Mariam A; Ali, Nawab; Stefanova, Rossina; Khan, Ashraf A

2014-04-01

A total of 60 Salmonella enterica serovar (ser.) Enteritidis isolates, 28 from poultry houses and 32 from clinical samples, were isolated during 2010. These isolates were subjected to testing and analyzed for antibiotic resistance, virulence genes, plasmids and plasmid replicon types. To assess genetic diversity, pulsed-field gel electrophoresis (PFGE) fingerprinting, using the XbaI restriction enzyme, Multiple-Locus Variable-Number Tandem Repeat Analysis (MLVA) and plasmid profiles were performed. All isolates from poultry, and 10 out of 32 clinical isolates were sensitive to ampicillin, chloramphenicol, gentamicin, kanamycin, nalidixic acid, sulfisoxazole, streptomycin, and tetracycline. Twenty-one of thirty-two clinical isolates were resistant to ampicillin and tetracycline, and one isolate was resistant to nalidixic acid. PFGE typing of sixty ser. Enteritidis isolates by XbaI resulted in 10-12 bands and grouped into six clusters each with similarity from 95% to 81%. The MLVA analysis of sixty isolates gave 18 allele profiles with the majority of isolates displayed in three groups, and two clinical isolates found to be new in the PulseNet national MLVA database. All isolates were positive for 12 or more of the 17 virulence genes mostly found in S. enterica (spvB, spiA, pagC, msgA, invA, sipB, prgH, spaN, orgA, tolC, iroN, sitC, IpfC, sifA, sopB, and pefA) and negative for one gene (cdtB). All isolates carried a typical 58 kb plasmid, type Inc/FIIA. Three poultry isolates and one clinical isolate carried small plasmids with 3.8, 6, 7.6 and 11.5 kb. Ten of the clinical isolates carried plasmids, with sizes 36 and 38 kb, types IncL/M and IncN, and one isolate carried an 81 kb plasmid, type IncI. Southern hybridization of a plasmid with an Inc/FIIA gene probe hybridized one large 58 kb plasmid in all isolates. Several large and small plasmids from poultry isolates were not typed by our PCR-based method. These results confirmed that PFGE fingerprinting has limited discriminatory power for ser. Enteritidis in both poultry and clinical sources. However, the plasmid and MLVA allele profiles were a useful and important epidemiology tool to discriminate outbreak strains of ser. Enteritidis from poultry and clinical samples. Published by Elsevier Ltd.

Assessing the genome level diversity of Listeria monocytogenes from contaminated ice cream and environmental samples linked to a listeriosis outbreak in the United States.

PubMed

Chen, Yi; Luo, Yan; Curry, Phillip; Timme, Ruth; Melka, David; Doyle, Matthew; Parish, Mickey; Hammack, Thomas S; Allard, Marc W; Brown, Eric W; Strain, Errol A

2017-01-01

A listeriosis outbreak in the United States implicated contaminated ice cream produced by one company, which operated 3 facilities. We performed single nucleotide polymorphism (SNP)-based whole genome sequencing (WGS) analysis on Listeria monocytogenes from food, environmental and clinical sources, identifying two clusters and a single branch, belonging to PCR serogroup IIb and genetic lineage I. WGS Cluster I, representing one outbreak strain, contained 82 food and environmental isolates from Facility I and 4 clinical isolates. These isolates differed by up to 29 SNPs, exhibited 9 pulsed-field gel electrophoresis (PFGE) profiles and multilocus sequence typing (MLST) sequence type (ST) 5 of clonal complex 5 (CC5). WGS Cluster II contained 51 food and environmental isolates from Facility II, 4 food isolates from Facility I and 5 clinical isolates. Among them the isolates from Facility II and clinical isolates formed a clade and represented another outbreak strain. Isolates in this clade differed by up to 29 SNPs, exhibited 3 PFGE profiles and ST5. The only isolate collected from Facility III belonged to singleton ST489, which was in a single branch separate from Clusters I and II, and was not associated with the outbreak. WGS analyses clustered together outbreak-associated isolates exhibiting multiple PFGE profiles, while differentiating them from epidemiologically unrelated isolates that exhibited outbreak PFGE profiles. The complete genome of a Cluster I isolate allowed the identification and analyses of putative prophages, revealing that Cluster I isolates differed by the gain or loss of three putative prophages, causing the banding pattern differences among all 3 AscI-PFGE profiles observed in Cluster I isolates. WGS data suggested that certain ice cream varieties and/or production lines might have contamination sources unique to them. The SNP-based analysis was able to distinguish CC5 as a group from non-CC5 isolates and differentiate among CC5 isolates from different outbreaks/incidents.

Assessing the genome level diversity of Listeria monocytogenes from contaminated ice cream and environmental samples linked to a listeriosis outbreak in the United States

PubMed Central

Chen, Yi; Luo, Yan; Curry, Phillip; Timme, Ruth; Melka, David; Doyle, Matthew; Parish, Mickey; Hammack, Thomas S.; Allard, Marc W.; Brown, Eric W.; Strain, Errol A.

2017-01-01

A listeriosis outbreak in the United States implicated contaminated ice cream produced by one company, which operated 3 facilities. We performed single nucleotide polymorphism (SNP)-based whole genome sequencing (WGS) analysis on Listeria monocytogenes from food, environmental and clinical sources, identifying two clusters and a single branch, belonging to PCR serogroup IIb and genetic lineage I. WGS Cluster I, representing one outbreak strain, contained 82 food and environmental isolates from Facility I and 4 clinical isolates. These isolates differed by up to 29 SNPs, exhibited 9 pulsed-field gel electrophoresis (PFGE) profiles and multilocus sequence typing (MLST) sequence type (ST) 5 of clonal complex 5 (CC5). WGS Cluster II contained 51 food and environmental isolates from Facility II, 4 food isolates from Facility I and 5 clinical isolates. Among them the isolates from Facility II and clinical isolates formed a clade and represented another outbreak strain. Isolates in this clade differed by up to 29 SNPs, exhibited 3 PFGE profiles and ST5. The only isolate collected from Facility III belonged to singleton ST489, which was in a single branch separate from Clusters I and II, and was not associated with the outbreak. WGS analyses clustered together outbreak-associated isolates exhibiting multiple PFGE profiles, while differentiating them from epidemiologically unrelated isolates that exhibited outbreak PFGE profiles. The complete genome of a Cluster I isolate allowed the identification and analyses of putative prophages, revealing that Cluster I isolates differed by the gain or loss of three putative prophages, causing the banding pattern differences among all 3 AscI-PFGE profiles observed in Cluster I isolates. WGS data suggested that certain ice cream varieties and/or production lines might have contamination sources unique to them. The SNP-based analysis was able to distinguish CC5 as a group from non-CC5 isolates and differentiate among CC5 isolates from different outbreaks/incidents. PMID:28166293

Absence of CTX-M Enzymes but High Prevalence of Clones, Including Clone ST131, among Fecal Escherichia coli Isolates from Healthy Subjects Living in the Area of Paris, France▿

PubMed Central

Leflon-Guibout, Véronique; Blanco, Jorge; Amaqdouf, Karim; Mora, Azucena; Guize, Louis; Nicolas-Chanoine, Marie-Hélène

2008-01-01

Quinolone-resistant and CTX-M-15-producing Escherichia coli isolates belonging to clone ST131 have been reported in the community. This study was designed to identify these E. coli isolates in the stools of 332 independent healthy subjects living in the area of Paris, France. Stools were plated on media without antibiotics, in order to obtain the dominant (Dm) fecal E. coli strain, and with nalidixic acid (NAL) and cefotaxime. Quinolone susceptibility, phylogenetic groups, and molecular profiles, including multilocus sequence types (ST), were determined for all NAL-resistant (NAL-R) isolates. Groups were also determined for the Dm strains from participants with NAL-R isolates and from a subgroup without NAL-R isolates. All B2 isolates were typed; pulsed-field gel electrophoresis was performed for the ST131 isolates, and the results were compared with those for intercontinental clone ST131. Two participants (0.6%) had extended-spectrum β-lactamase-producing (SHV-2, TEM-52) fecal E. coli isolates, and 51 (15%) had NAL-R isolates; 51% of NAL-R isolates belonged to phylogenetic group A, 31% to group D, 16% to group B2, and 2% to group B1. The Dm strain was NAL-R in 3.3% of the 332 subjects. Forty-nine percent of the NAL-R isolates belonged to clones: ST10 and ST606 for group A isolates, ST117 and ST393 for group D isolates. Of all B2 isolates studied from 100 subjects (8 NAL-R strains; 19 NAL-susceptible dominant strains), 52% belonged to three clones: ST131 (n = 7), ST95 (n = 4), and ST141 (n = 3). This is the first study to show the presence of fecal E. coli isolates of clone ST131 in 7% of independent healthy subjects not colonized by CTX-M-15-producing isolates. PMID:18842941

SUSCEPTIBILITY OF RESPIRATORY ISOLATES OF STREPTOCOCCUS PNEUMONIAE ISOLATED FROM CHILDREN HOSPITALIZED IN THE CLINICAL CENTER NIS.

PubMed

Dinić, Marina M; Mladenović Antić, Snezana; Kocić, Branislava; Stanković Dordević, Dobrila; Vrbić, Miodrag; Bogdanović, Milena

2016-01-01

Streptococcus pneumoniae is one of the most common causes of respiratory infections. The aim was to study the susceptibility to antimicrobial agents of respiratory isolates ofStreptococcus pneumoniae obtained from hospitalized children. A total of 190 respiratory pneumococcal isolates obtained from children aged from 0 to 14 years were isolated and identified by using standard microbiological methods. Susceptibility to oxacillin, erythromycin, clindamycin, tetracycline, cotrimoxazole, ofloxacin and rifampicin was tested by disc diffusion method. Minimal inhibitory concentrations for amoxicillin and ceftriaxone were determined by means of E test. The macrolide-resistant phenotype was detected by double disc diffusion test. All tested isolates were susceptible to amoxicillin and ceftriaxone. The minimal amoxicillin concentration inhibiting the growth of 50% of isolates and of 90% of isolates was 0.50 microg/ml and 1.0 microg/ml, respectively and the minimal ceftriaxone concentration inhibiting the growth of 50% of isolates and of 90% of isolates was 0.25 microg/ml and 0.50 microg/ml, respectively. Susceptibility to erythromycin and clindamycin was observed in 21.6% and 29.47% of isolates, respectively. The resistence to macrolides-M phenotype was detected in 10.07% of isolates and constitutive macrolide-lincosamide-streptogramin phenotype (constitutive MLS phenotype) was found in 89.93% of isolates. All tested isolates were susceptible to ofloxacin and rifampicin. Amoxicillin could be the therapy of choice in pediatric practice. The macrolides should not be recommended for the empirical therapy of pneumococcal respiratory tract infection in our local area.

Genetic Characterization of Soybean Rhizobia Isolated from Different Ecological Zones in North-Eastern Afghanistan.

PubMed

Habibi, Safiullah; Ayubi, Abdul Ghani; Ohkama-Ohtsu, Naoko; Sekimoto, Hitoshi; Yokoyama, Tadashi

2017-03-31

Seventy rhizobial isolates were obtained from the root nodules of two soybean (Glycine max) cultivars: Japanese cultivar Enrei and USA cultivar Stine3300, which were inoculated with different soil samples from Afghanistan. In order to study the genetic properties of the isolates, the DNA sequences of the 16S rRNA gene and symbiotic genes (nodD1 and nifD) were elucidated. Furthermore, the isolates were inoculated into the roots of two soybean cultivars, and root nodule numbers and nitrogen fixation abilities were subsequently evaluated in order to assess symbiotic performance. Based on 16S rRNA gene sequences, the Afghanistan isolates obtained from soybean root nodules were classified into two genera, Bradyrhizobium and Ensifer. Bradyrhizobium isolates accounted for 54.3% (38) of the isolates, and these isolates had a close relationship with Bradyrhizobium liaoningense and B. yuanmingense. Five out of the 38 Bradyrhizobium isolates showed a novel lineage for B. liaoningense and B. yuanmingense. Thirty-two out of the 70 isolates were identified as Ensifer fredii. An Ensifer isolate had identical nodD1 and nifD sequences to those in B. yuanmingense. This result indicated that the horizontal gene transfer of symbiotic genes occurred from Bradyrhizobium to Ensifer in Afghanistan soil. The symbiotic performance of the 14 tested isolates from the root nodules of the two soybean cultivars indicated that Bradyrhizobium isolates exhibited stronger acetylene reduction activities than Ensifer isolates. This is the first study to genetically characterize soybean-nodulating rhizobia in Afghanistan soil.

Whole-genome comparison of urinary pathogenic Escherichia coli and faecal isolates of UTI patients and healthy controls.

PubMed

Nielsen, Karen Leth; Stegger, Marc; Kiil, Kristoffer; Godfrey, Paul A; Feldgarden, Michael; Lilje, Berit; Andersen, Paal S; Frimodt-Møller, Niels

2017-12-01

The faecal flora is a common reservoir for urinary tract infection (UTI), and Escherichia coli (E. coli) is frequently found in this reservoir without causing extraintestinal infection. We investigated these E. coli reservoirs by whole-genome sequencing a large collection of E. coli from healthy controls (faecal), who had never previously had UTI, and from UTI patients (faecal and urinary) sampled from the same geographical area. We compared MLST types, phylogenetic relationship, accessory genome content and FimH type between patient and control faecal isolates as well as between UTI and faecal-only isolates, respectively. Comparison of the accessory genome of UTI isolates to faecal isolates revealed 35 gene families which were significantly more prevalent in the UTI isolates compared to the faecal isolates, although none of these were unique to one of the two groups. Of these 35, 22 belonged to a genomic island and three putatively belonged to a type VI secretion system (T6SS). MLST types and SNP phylogeny indicated no clustering of the UTI or faecal E. coli from patients distinct from the control faecal isolates, although there was an overrepresentation of UTI isolates belonging to clonal lineages CC73 and CC12. One combination of mutations in FimH, N70S/S78N, was significantly associated to UTI, while phylogenetic analysis of FimH and fimH identified no signs of distinct adaptation of UTI isolates compared to faecal-only isolates not causing UTI. In summary, the results showed that (i) healthy women who had never previously had UTI carried faecal E. coli which were overall closely related to UTI and faecal isolates from UTI patients; (ii) UTI isolates do not cluster separately from faecal-only isolates based on SNP analysis; and (iii) 22 gene families of a genomic island, putative T6SS proteins as well as specific metabolism and virulence associated proteins were significantly more common in UTI isolates compared to faecal-only isolates and (iv) evolution of fimH for these isolates was not linked to the clinical source of the isolates, apart from the mutation combination N70S/S78N, which was correlated to UTI isolates of phylogroup B2. Combined, these findings illustrate that faecal and UTI isolates, as well as faecal-only and faecal-UTI isolates, are closely related and can only be distinguished, if at all, by their accessory genome. Copyright © 2017 Elsevier GmbH. All rights reserved.

Genetic Characterization of Atypical Enteropathogenic Escherichia coli Isolates from Ewes' Milk, Sheep Farm Environments, and Humans by Multilocus Sequence Typing and Pulsed-Field Gel Electrophoresis

PubMed Central

Otero, Verónica; Rodríguez-Calleja, José-María; Otero, Andrés; García-López, María-Luisa

2013-01-01

A collection of 81 isolates of enteropathogenic Escherichia coli (EPEC) was obtained from samples of bulk tank sheep milk (62 isolates), ovine feces (4 isolates), sheep farm environment (water, 4 isolates; air, 1 isolate), and human stool samples (9 isolates). The strains were considered atypical EPEC organisms, carrying the eae gene without harboring the pEAF plasmid. Multilocus sequence typing (MLST) was carried out with seven housekeeping genes and 19 sequence types (ST) were detected, with none of them having been previously reported for atypical EPEC. The most frequent ST included 41 strains isolated from milk and human stool samples. Genetic typing by pulsed-field gel electrophoresis (PFGE) resulted in 57 patterns which grouped in 24 clusters. Comparison of strains isolated from the different samples showed phylogenetic relationships between milk and human isolates and also between milk and water isolates. The results obtained show a possible risk for humans due to the presence of atypical EPEC in ewes' milk and suggest a transmission route for this emerging pathogen through contaminated water. PMID:23872571

Phenotypic and genetic characterizations of Streptococcus dysgalactiae strains isolated from fish collected in Japan and other Asian countries.

PubMed

Abdelsalam, Mohamed; Chen, Shih-Chu; Yoshida, Terutoyo

2010-01-01

Lancefield group C Streptococcus dysgalactiae is an emerging fish pathogen, which was first isolated in 2002 in Japan. Streptococcus dysgalactiae isolates collected from diseased fish in Japan (n=12), Taiwan (n=12), China (n=2), Malaysia (n=3), and Indonesia (n=1) were characterized using biased sinusoidal field gel electrophoresis (BSFGE), sodA gene sequence analysis, and antimicrobial susceptibility. These isolates exhibited high phenotypic homogeneity irrespective of the countries from where the strains were collected. Seventeen isolates were found to be resistant to oxytetracycline and carried the tet(M) gene, except for the strains collected in Taiwan and the PP1564 strain collected in China. The sodA gene sequence analysis revealed that 23 isolates were identical, except for one Japanese isolate (KNH07902), in which a single nucleotide differed from that of the other isolates. Based on BSFGE typing by ApaI macrorestriction, the isolates - including the Japanese, Taiwanese, and Chinese isolates - could be grouped into one main cluster at a 70% similarity level. However, the macrorestriction genotypes of some isolates were apparently distinct from those of the main cluster.

Single spore isolation and morphological characterization of local Malaysian isolates of rice blast fungus Magnoporthe grisea

NASA Astrophysics Data System (ADS)

Mishra, Ankitta; Ratnam, Wickneswari; Bhuiyan, Md Atiqur Rahman; Ponaya, Ariane; Jena, Khisord K.

2015-09-01

Rice blast is a destructive disease, caused by the fungal pathogen Magnaporthe grisea. It causes considerable damage to rice and leads to crop loss in rice growing regions worldwide. Although fungicides can be used to control rice blast, they generate additional cost in rice production and contamination of environment and food. Therefore, the use of resistant varieties is thought to be one of the most economically and environmentally efficient ways of crop protection from the disease. Six new local Malaysian isolates of M. grisea were isolated using single spore isolation method. Five isolates were from infected leaf samples collected from Kompleks Latihan MADA, Kedah and one was from Kelantan. These isolates were identified using morphological characteristics and microscopic studies and later confirmed by ITSequences. These isolates were induced to sporulate and used for greenhouse screening on two differential rice varieties: Mahsuri (susceptible) and Pongsu Seribu 2 (resistant). Among the 6 isolates, isolate number 3 was found to be the most virulent showing high sporulation while isolate number 4 was very slow growing, and the least virulent.

A Prospective Study of Social Isolation, Loneliness, and Mortality in Finland.

PubMed

Tanskanen, Jussi; Anttila, Timo

2016-11-01

To estimate the simultaneous effects of social isolation and loneliness on mortality. We analyzed a representative Finnish sample (n = 8650) from the cross-sectional Living Conditions Survey of 1994, with a 17-year follow-up period (1995-2011), by using Cox regression models adjusted for several possible confounding variables. We examined the possible nonlinear threshold effect of social isolation on mortality. The analyses revealed that social isolation predicted mortality even after we controlled for loneliness and control variables. The connection between social isolation and mortality was linear in nature and there was no synergistic effect between social isolation and loneliness. The effect of loneliness became nonsignificant when studied simultaneously with social isolation. This study reveals strong evidence for an adverse effect of social isolation on mortality. Social isolation and loneliness seem to have distinct pathways to mortality and health. The results imply that the risk of mortality exists along a continuum, affecting not only those who experience extreme social isolation, but also those who suffer from mild to progressively increasing intensity of isolation.

Antimicrobial Sensitivity of Avibacterium paragallinarum Isolates from Four Latin American Countries.

PubMed

Luna-Galaz, G A; Morales-Erasto, V; Peñuelas-Rivas, C G; Blackall, P J; Soriano-Vargas, E

2016-09-01

The antimicrobial sensitivity of 11 reference strains and 66 Avibacterium paragallinarum isolates from four Latin American countries was investigated. All 11 reference strains were sensitive to amoxicillin-clavulanic acid, ampicillin, fosfomycin, gentamicin, kanamycin, neomycin, penicillin, tetracycline, and trimethoprim-sulfamethoxazole. The 11 reference strains were all resistant to lincomycin. All isolates (100%) from Mexico, Panama, and Peru were sensitive to amoxicillin-clavulanic acid, ampicillin, and fosfomycin. The Ecuadorian isolates showed some level of resistance to all 16 agents tested. The Ecuadorian isolates were significantly more sensitive to erythromycin, lincomycin, and streptomycin, and significantly more resistant to gentamicin, kanamycin, penicillin, and tetracycline, than the Mexican isolates. A total of 57.5% (38/66) of tested isolates were multi-drug resistant (MDR), with 16 MDR patterns detected in 88.4% (23/26) of the antimicrobial-resistant isolates from Ecuador, and 8 MDR patterns detected in 42.8% (15/35) of the antimicrobial-resistant isolates from Mexico. In conclusion, the variation in antimicrobial sensitivity patterns between isolates from Ecuador and Mexico emphasizes the importance of active, ongoing monitoring of A. paragallinarum isolates.

Characterization of the Aeromonas hydrophila group isolated from retail foods of animal origin.

PubMed

Palumbo, S A; Bencivengo, M M; Del Corral, F; Williams, A C; Buchanan, R L

1989-05-01

During a recent survey of retail fresh foods of animal origin (fish and seafood, raw milk, poultry, and red meats) for organisms of the Aeromonas hydrophila group, we isolated representative strains from the various foods. In this study, we sought to characterize these isolates for biochemical properties and virulence-associated factors and to compare the food isolates with clinical isolates. We identified all food and clinical isolates as A. hydrophila and found that all isolates were typical in their biochemical reactions. Examination of the isolates for various virulence-associated factors indicated that most food and clinical isolates were serum resistant, beta-hemolytic, cytotoxin positive (against Y1 adrenal cells), hemagglutinin positive, Congo red positive, elastase positive, and staphylolysin positive. Mouse 50% lethal doses were log10 8 to 9 CFU for most isolates. All isolates had biotypes identical to those of enterotoxin-positive strains. The public health significance of these organisms in foods is not known at present, although their widespread occurrence and ability to grow competitively in foods kept at 5 degrees C represents a potential hazard.

Serotypes and DNA fingerprint profiles of Pasteurella multocida isolated from raptors

USGS Publications Warehouse

Wilson, M.A.; Duncan, R.M.; Nordholm, G.E.; Berlowski, B.M.

1995-01-01

Pasteurella multocida isolates from 21 raptors were examined by DNA fingerprint profile and serotyping methods. Isolates were obtained from noncaptive birds of prey found in 11 states from November 28, 1979, through February 10, 1993. Nine isolates were from bald eagles, and the remaining isolates were from hawks, falcons, and owls. Seven isolates were members of capsule group A, and 14 were nonencapsulated. One isolate was identified as somatic type 3, and another was type 3,4,7; both had unique HhaI DNA fingerprint profiles. Nineteen isolates expressed somatic type 1 antigen; HhaI profiles of all type 1 isolates were identical to each other and to the HhaI profile of the reference somatic type 1, strain X-73. The 19 type 1 isolates were differentiated by sequential digestion of DNA with HpaII; four HpaII fingerprint profiles were obtained. The HpaII profile of one isolate was identical to the HpaII profile of strain X-73. Incidence of P. multocida somatic type 1 in raptors suggests that this type may be prevalent in other wildlife or wildlife environments.

Isolation and molecular characterization of Salmonella enterica serovar Javiana from food, environmental and clinical samples.

PubMed

Mezal, Ezat H; Stefanova, Rossina; Khan, Ashraf A

2013-06-03

A total of 50 Salmonella enterica serovar Javiana isolates, isolated from food, environmental and clinical samples, were analyzed for antibiotic resistance, presence of virulence genes, plasmids and plasmid replicon types. To assess the genetic diversity, pulsed-field gel electrophoresis (PFGE) fingerprinting and plasmid profiles were performed. All of the isolates were sensitive to chloramphenicol, nalidixic acid, and sulfisoxazole, and four isolates showed intermediate resistance to gentamicin or kanamycin. Eleven isolates, including representatives from each of the source types, were resistant to ampicillin. Four isolates from either clinical or environmental sources were resistant to tetracycline, while an additional 20 isolates showed intermediate resistance to this drug. Fourteen isolates, primarily from food sources, showed intermediate resistance to streptomycin. The S. Javiana isolates were screened by PCR for 17 virulence genes (spvB, spiA, pagC, msgA, invA, sipB, prgH, spaN, orgA, tolC, iroN, sitC, IpfC, sifA, sopB, cdtB, and pefA). All isolates were positive for nine to fourteen of these genes, but none were positive for pefA, spvB and lpfC, which are typically present on the Salmonella virulence plasmid. Seven of the virulence genes including cdtB were found in all 50 isolates, suggesting that S. Javiana from food and environmental sources had virulence similar to clinical isolates. Four clinical isolates and two food isolates carried one or more plasmids of approximately 30, 38, and 58 kb, with the 58 kb plasmids belonging to incompatibility group IncFIIA. Two clinical isolates carried IncI1 type mega plasmid (80 kb), and one clinical isolate carried plasmids of 4.5 and 7 kb. The PFGE profiles resulted 34 patterns in five clusters at a 90% similarity threshold. Our results indicate that S. Javiana isolates have a diverse clonal population among the clinical, food and environmental samples and this serotype possesses several virulent genes and plasmids that can contribute to the development of salmonellosis in human. This study provides data that support the potential transmission of S. Javiana virulence factors from food and environmental sources to cause infections in humans. Published by Elsevier B.V.

[Prevalence and characteristics of social isolation in the elderly in a dormitory suburb according to household composition].

PubMed

Saito, Masashige; Fujiwara, Yoshinori; Kobayashi, Erika; Fukaya, Taro; Nishi, Mariko; Shinkai, Syoji

2010-09-01

The purpose of this paper is to clarify the prevalence and characteristics of social isolation in elderly individuals living alone or with others in a dormitory suburb, and to examine the characteristics of non-responders to questions concerning social isolation. Data were obtained from a survey of 978 elderly (aged 65 and over) individuals living alone and 1,529 elderly individuals living together in Wako-shi, Saitama. The frequencies of contacts with non-co-resident children, relatives, friends, and neighbors were used to operationally define social isolation. Based on these responses, those who had contact with any of the above groups less than 2 or 3 times a month were termed "isolated elderly", those who had contact with these more than once a week were termed "non-isolated elderly", and those who did not answer these questions were termed "nonresponders". In addition, a logistic regression analysis was conducted to examine differences among the characteristics of isolated elderly between these households. Also, a multiple comparison analysis was performed to clarify the characteristics of non-responders. The major findings were as follows: 1) rates of prevalence of the isolated elderly were 24.01% for elderly living alone, and 28.7% for elderly living with others, respectively; 2) the elderly who were male, childless or living distant from children, and of lower income tended to be more socially isolated whether they were living alone or not; 3) a difference in isolation was noted between living alone and together in that divorced and unmarried elderly tended to be isolated when living alone while older and frail elderly tended to be isolated even when living together; 4) the characteristics of "nonresponders" were similar to those of the isolated elderly for both those living alone and living together. These findings suggest that social support for the socially isolated elderly should be adequately planned considering differences in the characteristics of isolation between those living alone and living together. It is also suggested that the non-responders in some questions relating to social isolation should be considered as likely to belong to the isolation groups when screening for the isolated elderly.

Antibiotic resistance profile and virulence genes of uropathogenic Escherichia coli isolates in relation to phylogeny.

PubMed

Adib, N; Ghanbarpour, R; Solatzadeh, H; Alizade, H

2014-03-01

Escherichia coli (E. coli) strains are the major cause of urinary tract infections (UTI) and belong to the large group of extra-intestinal pathogenic E. coli. The purposes of this study were to determine the antibiotic resistance profile, virulence genes and phylogenetic background of E. coli isolates from UTI cases. A total of 137 E. coli isolates were obtained from UTI samples. The antimicrobial susceptibility of confirmed isolates was determined by disk diffusion method against eight antibiotics. The isolates were examined to determine the presence and prevalence of selected virulence genes including iucD, sfa/focDE, papEF and hly. ECOR phylo-groups of isolates were determined by detection of yjaA and chuA genes and fragment TspE4.C2. The antibiogram results showed that 71% of the isolates were resistant to cefazolin, 60.42% to co-trimoxazole, 54.16% to nalidixic acid, 36.45% to gentamicin, 29.18% to ciprofloxacin, 14.58% to cefepime, 6.25% to nitrofurantoin and 0.00% to imipenem. Twenty-two antibiotic resistance patterns were observed among the isolates. Virulence genotyping of isolates revealed that 58.39% isolates had at least one of the four virulence genes. The iucD gene was the most prevalent gene (43.06%). The other genes including sfa/focDE, papEF and hly genes were detected in 35.76%, 18.97% and 2.18% isolates, respectively. Nine combination patterns of the virulence genes were detected in isolates. Phylotyping of 137 isolates revealed that the isolates fell into A (45.99%), B1 (13.14%), B2 (19.71%) and D (21.16%) groups. Phylotyping of multidrug resistant isolates indicated that these isolates are mostly in A (60.34%) and D (20.38%) groups. In conclusion, the isolates that possessed the iucD, sfa/focDE, papEF and hly virulence genes mostly belonged to A and B2 groups, whereas antibiotic resistant isolates were in groups A and D. Escherichia coli strains carrying virulence factors and antibiotic resistance are distributed in specific phylogenetic background.

Differences in virulence genes and genome patterns of mastitis-associated Staphylococcus aureus among goat, cow, and human isolates in Taiwan.

PubMed

Chu, Chishih; Wei, Yajiun; Chuang, Shih-Te; Yu, Changyou; Changchien, Chih-Hsuan; Su, Yaochi

2013-03-01

A total of 117 mastitis-associated Staphylococcus aureus isolates from cow, goat, and human patients were analyzed for differences in antibiotic susceptibility, virulence genes, and genotypes using accessory gene regulator (agr) typing, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Multidrug-resistant (MDR) S. aureus were commonly found in all sources, though they were predominantly found in human and goat isolates. Almost 70% of the isolates were resistant to ampicillin and penicillin. Host-associated virulence genes were identified as follows: tst, a gene encoding toxic shock syndrome toxin, was found in goat isolates; lukED and lukM, genes encoding leukocidin, found in cow isolates; lukPV, a gene encoding leukocidin, found in human isolates; and eta, a gene encoding for exfoliative toxin, found in both human and cow isolates. All four types of hemolysin, α, β, γ, and δ, were identified in human isolates, three types (α, γ, and δ), were identified in cow isolates, and two types (α and δ) were identified in goat isolates. Agr-typing determined agr1 to be the main subtype in human and cow isolates. PFGE and MLST analysis revealed the presence of diverse genotypes among the three sources. In conclusion, mastitis-associated, genetically diverse strains of MDR S. aureus differed in virulence genes among human, cow, and goat isolates.

Isolation and characterization of an atypical Siberian sturgeon herpesvirus strain in Russia: novel North American Acipenserid herpesvirus 2 strain in Europe?

PubMed

Doszpoly, A; Kalabekov, I M; Breyta, R; Shchelkunov, I S

2017-10-01

Siberian sturgeon herpesvirus (SbSHV) was isolated in Russia for the first time in 2006. Nine SbSHV isolates were recovered from different fish hatcheries producing the same cytopathic effect in cell cultures, the same clinical signs and mortality kinetics in virus-infected fish and the same virus neutralization pattern and shared identical nucleotide sequences. In 2011, a new isolate was recovered from juvenile sturgeon, which caused completely different cytopathic effect. That isolate was not readily neutralized by Siberian sturgeon hyperimmune antisera, and its DNA was not recognized by the routine PCR developed for SbSHV detection. Molecular study of the novel isolate revealed that it was more closely related to North American Acipenserid herpesvirus 2 (AciHV-2) isolates from white sturgeon, while the genome sequences of the former SbSHV isolates showed high similarity to the AciHV-2 isolated from shortnose sturgeon. While clinical signs and mortality caused by the novel isolate in infected Siberian sturgeon were similar to those of the formerly described SbSHV isolates, the incubation period and mean time to death produced by the novel isolate were twice as long. The differences between the former isolates and the recent one suggest that a novel SbSHV strain emerged in Europe and the molecular findings imply its North American origin. © 2017 John Wiley & Sons Ltd.

Staphylococcus aureus isolated from wastewater treatment plants in Tunisia: occurrence of human and animal associated lineages.

PubMed

Ben Said, Meriam; Abbassi, Mohamed Salah; Gómez, Paula; Ruiz-Ripa, Laura; Sghaier, Senda; Ibrahim, Chourouk; Torres, Carmen; Hassen, Abdennaceur

2017-08-01

The objective was to characterize Staphylococcus aureus isolated from two wastewater treatment plants (WWTPs) located in Tunis City (Tunisia), during the period 2014-2015. Genetic lineages, antibiotic resistance mechanisms and virulence factors were determined for the recovered isolates. S. aureus isolates were recovered from 12 of the 62 wastewater samples tested (19.35%), and one isolate/sample was characterized, all of them being methicillin-susceptible (MSSA). Six spa types (t587, t674, t224, t127, t701 and t1534) were found among the 12 isolates, and the spa-t587, associated with the new sequence type ST3245, was the most predominant one (7 isolates). The remaining isolates were assigned to five clonal complexes (CC5, CC97, CC1, CC6 and CC522) according to the sequence-type determined and/or the spa-type detected. S. aureus isolates were ascribed to agrI (n = 3), agrII (n = 7) and agrIII (n = 1); however, one isolate was non-typeable. S. aureus showed resistance to (number of isolates): penicillin (12), erythromycin (7), tetracycline (one) and clindamycin (one). Among the virulence factors investigated, only one isolate harboured the tst gene, encoding the TSST-1 (toxic shock syndrome toxin 1). Despite the low number of studied isolates, the present study reports the occurrence of both human- and animal-associated S. aureus clonal complexes in WWTPs in Tunisia.

Isolation and Identification of cellulolytic bacteria from mangrove sediment in Bangka Island

NASA Astrophysics Data System (ADS)

Kurniawan, A.; Prihanto, A. A.; Sari, S. P.; Febriyanti, D.; Kurniawan, A.; Sambah, A. B.; Asriani, E.

2018-04-01

Cellulolytic bacteria is bacteria which hydrolyze cellulose to reducing sugars. This research aims to obtain cellulolytic bacteria from the sediment of mangroves in Bangka island. Reasearch was conducted from March to August 2017. Sampling was conducted at Sungailiat, and Tukak Sadai, South of Bangka. Bacteria was isolated using 1% Carboxymetyl Cellulosa (CMC). The isolation resulted in four isolates from Sungailiat and nine isolates from Tukak Sadai. Total five isolates, namely Bacillus pumilus, Pseudomonas sp., Bacillus amyloliquefacien, Bacillus alvei, Bacillus coagulant were identified. The best isolates that produced cellulose was Pseudomonas aeruginosa.

Clinical features and molecular characteristics of childhood community-associated methicillin-resistant Staphylococcus aureus infection in a medical center in northern Taiwan, 2012.

PubMed

Wang, Hong-Kai; Huang, Chun-Yen; Huang, Yhu-Chering

2017-07-05

Since first reported in 2002, the rate of methicillin-resistant Staphylococcus aureus (MRSA) among childhood community-associated (CA) S. aureus infection in Taiwan increased significantly up to 2005. There have been no reports on this issue since then. We prospectively collected clinical S. aureus isolates from the patients <19 years of age in a university-affiliated hospital in 2012. Only first isolate from each patient was included. The medical records were retrospectively reviewed and the patients were classified as CA or healthcare-associated (HA) by the standard epidemiologic criteria. Isolates as CA-MRSA were further characterized by pulsed-field gel electrophoresis, staphylococcal cassette chromosome (SCCmec) typing, and multilocus sequence typing. A total of 409 S. aureus isolates were included, and 260 (63.6%) were MRSA. The proportion of MRSA among all S. aureus isolates in 2012 increased significantly (p < 0.001) compared to that in 2004-2005. Of the 181 CA-MRSA isolates, 86.2% were identified from pus or wound. Nine pulsotypes were identified with two major types (type D, 119 (65.7%); type C, 27 (14.9%). Most of the isolates carried either SCCmec IV (66 isolates, 36%) or V T (112 isolates, 62%). 128 isolates (71%) carried Panton-Valentine leukocidin (PVL) genes. Clonal complex (CC) 59 accounted for 146 isolates (80.7%) of two major pulsotypes, CC45 for 19 isolates, ST30 for 6 isolates and ST8 (USA 300) for 4 isolates. In addition to penicillin (100%), most isolates were resistant to erythromycin (81%) and clindamycin (79.3%). Around two-thirds of childhood community-associated S. aureus infections in northern Taiwan were MRSA. Though CC59 is still the prevalent community clone, several new clones emerged in northern Taiwan.

Phenotypic and genotypic anti-microbial resistance profiles of campylobacters from untreated feedlot cattle and their environment.

PubMed

Minihan, D; Whyte, P; O'mahony, M; Cowley, D; O'halloran, F; Corcoran, D; Fanning, S; Collins, J D

2006-05-01

Anti-microbial resistance is an emerging public health issue. Farmed animals may act as reservoirs and potential sources of anti-microbial resistant Campylobacters. The aim of this study was to investigate the anti-microbial resistance profile of cattle and environmental Campylobacter isolates from normal untreated feedlot cattle, the role of the gyrA Thr-86-Ile mutation in ciprofloxacin-resistant Campylobacter jejuni isolates and the involvement of the tripartite CmeABC efflux system for multi-resistant C. jejuni isolates. The phenotypic anti-microbial resistance testing was carried out on 500 Campylobacter isolates (445 cattle isolates and 55 environmental isolates). In general, there was a higher level of anti-microbial resistance for the environmental isolates compared with the animal isolates, 45% of the animal isolates were resistant to one or more of the seven anti-microbials compared with 84% of the environmental isolates. The combined cattle and environmental Campylobacters had 34 (6.8%) isolates resistant to three or more of the seven anti-microbials tested on all isolates and 11 (2.2%) isolates were resistant to the seven anti-microbials. There was a substantial level of ciprofloxacin-resistant Campylobacters in both animal (8.5%) and environmental (21.8%) isolates. The gyrA Thr-86-Ile mutation was only present in five of 22 ciprofloxacin-resistant C. jejuni isolates investigated. No multi-drug-resistant associated mutation was detected in the CmeB or the CmeR regions investigated. In conclusion, our study observed a substantial level of Campylobacter anti-microbial resistance, highlighting the need for an active anti-microbial surveillance program for food animals in Ireland and the importance of the chosen sampling point can have on the findings of such a program.

Host Specialization in the Charcoal Rot Fungus, Macrophomina phaseolina.

PubMed

Su, G; Suh, S O; Schneider, R W; Russin, J S

2001-02-01

ABSTRACT To investigate host specialization in Macrophomina phaseolina, the fungus was isolated from soybean, corn, sorghum, and cotton root tissue and soil from fields cropped continuously to these species for 15 years in St. Joseph, LA. Chlorate phenotype of each isolate was determined after growing on a minimal medium containing 120 mM potassium chlorate. Consistent differences in chlorate sensitivity were detected among isolates from different hosts and from soil versus root. To further explore genetic differentiation among fungal isolates from each host, these isolates were examined by restriction fragment length polymorphism and random amplified polymorphic DNA (RAPD) analysis. No variations were observed among isolates in restriction patterns of DNA fragments amplified by polymerase chain reaction covering the internal transcribed spacer region, 5.8S rRNA and part of 25S rRNA, suggesting that M. phaseolina constitutes a single species. Ten random primers were used to amplify the total DNA of 45 isolates, and banding patterns resulting from RAPD analysis were compared with the neighbor-joining method. Isolates from a given host were genetically similar to each other but distinctly different from those from other hosts. Chlorate-sensitive isolates were distinct from chlorate-resistant isolates within a given host. In greenhouse tests, soybean, sorghum, corn, and cotton were grown separately in soil infested with individual isolates of M. phaseolina that were chosen based on their host of origin and chlorate phenotype. Root colonization and plant weight were measured after harvesting. More colonization of corn roots occurred when corn was grown in soil containing corn isolates compared with isolates from other hosts. However, there was no host specialization in isolates from soybean, sorghum, or cotton. More root colonization in soybean occurred with chlorate-sensitive than with chlorate-resistant isolates.

Antimicrobial susceptibilities and bacteriological characteristics of bovine Pseudomonas aeruginosa and Serratia marcescens isolates from mastitis.

PubMed

Ohnishi, Mamoru; Sawada, Takuo; Hirose, Kazuhiko; Sato, Reiichiro; Hayashimoto, Mizuki; Hata, Eiji; Yonezawa, Chizuko; Kato, Hajime

2011-12-29

The presence of metallo-β-lactamase (MBL)-producing and multidrug-resistant Pseudomonas aeruginosa (MDRP) strains among bovine isolates of Gram-negative bacilli, and O-serotypes of bovine Serratia marcescens and P. aeruginosa isolates have been reported rarely. The aims of this study were to (1) elucidate antimicrobial susceptibilities and O-serotypes of P. aeruginosa and S. marcescens isolates from bovine mastitis and the presence of MBL-producers and MDRP strains among them and (2) evaluate their relationships to human isolates. We investigated the MICs of 24 antimicrobials and O-serotypes for 116 P. aeruginosa and 55 S. marcescens isolates in Japan, primarily in 2006. A total of 171 isolates exhibited high antimicrobial susceptibilities with the exception of a partial drug. P. aeruginosa isolates exhibited high susceptibilities of ≥ 95.7% to ciprofloxacin, imipenem, meropenem, piperacillin, ceftazidime, cefepime, cefoperazone/sulbactam, amikacin, tobramycin, and gentamicin; however, they exhibited a susceptibility of only 69.8% to aztreonam. They exhibited substantial resistances to ceftriaxone, enrofloxacin, cefotaxime, and moxalactam. S. marcescens isolates exhibited high susceptibilities of ≥ 90.9% to kanamycin, ceftiofur, sulfamethoxazole-trimethoprim, and the 15 aforementioned drugs, but exhibited resistance to minocycline. Neither MBL-producers nor MDRP strains were detected among the 171 strains. The dominant serotypes of P. aeruginosa isolates were OG, OA, OB, OI, OF, OE, and OK; those of S. marcescens isolates were O6 and O5. Every S. marcescens isolate was pigmented. These findings suggest that bovine P. aeruginosa and S. marcescens isolates differ from human isolates from both antibiogram and phenotypic perspectives, and could help to evaluate differences in bacteriological characteristics between bovine and human isolates. Copyright © 2011 Elsevier B.V. All rights reserved.

Investigation of mercury thruster isolators. [service life

NASA Technical Reports Server (NTRS)

Mantenieks, M. A.

1973-01-01

Mercury ion thruster isolator lifetime tests were performed using different isolator materials and geometries. Tests were performed with and without the flow of mercury through the isolators in an oil diffusion pumped vacuum facility and cryogenically pumped bell jar. The onset of leakage current in isolators tested occurred in time intervals ranging from a few hours to many hundreds of hours. In all cases, surface contamination was responsible for the onset of leakage current and subsequent isolator failure. Rate of increase of leakage current and the leakage current level increased approximately exponentially with isolator temperature. Careful attention to shielding techniques and the elimination of sources of metal oxides appear to have eliminated isolator failures as a thruster life limiting mechanism.

Noise Performance of a 72 m Suspended FABRY-PÉROT Cavity

NASA Astrophysics Data System (ADS)

Dumas, Jean-Charles; Ju, Li; Barriga, Pablo; Zhao, Chunnong; Woolley, Andrew A.; Blair, David G.

We report on a seismic isolator with a relatively compact 3 m stack, combining new passive isolation techniques. It consists of three cascaded passive 3D isolator stages suspended from an Ultra Low Frequency (ULF) horizontal Robert linkage stage which itself is suspended from a ULF 3D pre-isolator. The 3D isolators use self-damping pendulums and Euler springs for the horizontal and vertical stages respectively, while the 3D pre-isolator is the combination of an inverse pendulum which provides low frequency horizontal pre-isolation, and a LaCoste linkage for low frequency vertical pre-isolation. Two isolators suspending mirror test masses have been built to form a 72 m optical cavity in order to test their performance. We report results which demonstrate residual motion at nanometer level at frequencies above 1 Hz.

Isolation and Characterization of Thermophilic Bacteria from Jordanian Hot Springs: Bacillus licheniformis and Thermomonas hydrothermalis Isolates as Potential Producers of Thermostable Enzymes.

PubMed

Mohammad, Balsam T; Al Daghistani, Hala I; Jaouani, Atef; Abdel-Latif, Saleh; Kennes, Christian

2017-01-01

The aim of this study was the isolation and characterization of thermophilic bacteria from hot springs in Jordan. Ten isolates were characterized by morphological, microscopic, biochemical, molecular, and physiological characteristics. Sequencing of the 16S rDNA of the isolates followed by BLAST search revealed that nine strains could be identified as Bacillus licheniformis and one isolate as Thermomonas hydrothermalis . This is the first report on the isolation of Thermomonas species from Jordanian hot springs. The isolates showed an ability to produce some thermostable enzymes such as amylase, protease, cellulose, gelatins, and lecithin. Moreover, the UPGMA dendrogram of the enzymatic characteristics of the ten isolates was constructed; results indicated a high phenotypic diversity, which encourages future studies to explore further industrial and environmental applications.

Characterization of Staphylococcus aureus isolates from raw milk sources in Victoria, Australia.

PubMed

McMillan, Kate; Moore, Sean C; McAuley, Catherine M; Fegan, Narelle; Fox, Edward M

2016-07-29

Highly pathogenic strains of Staphylococcus aureus can cause disease in both humans and animals. In animal species, including ruminants, S. aureus may cause severe or sub-clinical mastitis. Dairy animals with mastitis frequently shed S. aureus into the milk supply which can lead to food poisoning in humans. The aim of this study was to use genotypic and immunological methods to characterize S. aureus isolates from milk-related samples collected from 7 dairy farms across Victoria. A total of 30 S. aureus isolates were collected from milk and milk filter samples from 3 bovine, 3 caprine and 1 ovine dairy farms across Victoria, Australia. Pulsed Field Gel Electrophoresis (PFGE) identified 11 distinct pulsotypes among isolates; all caprine and ovine isolates shared greater than 80 % similarity regardless of source. Conversely, bovine isolates showed higher diversity. Multi-Locus Sequence Typing (MLST) identified 5 different sequence types (STs) among bovine isolates, associated with human or ruminant lineages. All caprine and ovine isolates were ST133, or a single allele variant of ST133. Two new novel STs were identified among isolates in this study (ST3183 and ST3184). With the exception of these 2 new STs, eBURST analysis predicted all other STs to be founding members of their associated clonal complexes (CCs). Analysis of genetic markers revealed a diverse range of classical staphylococcal enterotoxins (SE) among isolates, with 11 different SEs identified among bovine isolates, compared with just 2 among caprine and ovine isolates. None of the isolates contained mecA, or were resistant to oxacillin. The only antibiotic resistance identified was that of a single isolate resistant to penicillin; this isolate also contained the penicillin resistance gene blaZ. Production of SE was observed at 16 °C and/or 37 °C in milk, however no SE production was detected at 12 °C. Although this study characterized a limited number of isolates, bovine-associated isolates showed higher genetic diversity than their caprine or ovine counterparts. This was also reflected in a more diverse SE repertoire among bovine isolates. Very little antibiotic resistance was identified among isolates in this study. These results suggest maintaining the milk cold chain will minimise any risk from SE production and highlights the need to prevent temperature abuse.

Detection and characterization of broad-spectrum antipathogen activity of novel rhizobacterial isolates and suppression of Fusarium crown and root rot disease of tomato.

PubMed

Zhang, L; Khabbaz, S E; Wang, A; Li, H; Abbasi, P A

2015-03-01

To detect and characterize broad-spectrum antipathogen activity of indigenous bacterial isolates obtained from potato soil and soya bean leaves for their potential to be developed as biofungicides to control soilborne diseases such as Fusarium crown and root rot of tomato (FCRR) caused by Fusarium oxysporum f. sp. radicis-lycopersici (Forl). Thirteen bacterial isolates (Bacillus amyloliquefaciens (four isolates), Paenibacillus polymyxa (three isolates), Pseudomonas chlororaphis (two isolates), Pseudomonas fluorescens (two isolates), Bacillus subtilis (one isolate) and Pseudomonas sp. (one isolate)) or their volatiles showed antagonistic activity against most of the 10 plant pathogens in plate assays. Cell-free culture filtrates (CF) of five isolates or 1-butanol extracts of CFs also inhibited the growth of most pathogen mycelia in plate assays. PCR analysis confirmed the presence of most antibiotic biosynthetic genes such as phlD, phzFA, prnD and pltC in most Pseudomonas isolates and bmyB, bacA, ituD, srfAA and fenD in most Bacillus isolates. These bacterial isolates varied in the production of hydrogen cyanide (HCN), siderophores, β-1,3-glucanases, chitinases, proteases, indole-3-acetic acid, salicylic acid, and for nitrogen fixation and phosphate solubilization. Gas chromatography-mass spectrometry analysis identified 10 volatile compounds from 10 isolates and 18 compounds from 1-butanol extracts of CFs of five isolates. Application of irradiated peat formulation of six isolates to tomato roots prior to transplanting in a Forl-infested potting mix and field soil provided protection of tomato plants from FCRR disease and enhanced plant growth under greenhouse conditions. Five of the 13 indigenous bacterial isolates were antagonistic to eight plant pathogens, both in vitro and in vivo. Antagonistic and plant-growth promotion activities of these isolates might be related to the production of several types of antibiotics, lytic enzymes, phytohormones, secondary metabolites, siderophores and volatile compounds; however, any specific role of each needs to be determined. Indigenous antagonistic bacterial isolates have the potential to be developed as biofungicides for minimizing early crop losses due to soilborne diseases caused by Fusarium and other soilborne pathogens. © 2014 Her Majesty the Queen in Right of Canada © 2014 The Society for Applied Microbiology. Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada.

SYMBIODINIUM ISOLATES FROM STONY CORAL: ISOLATION, GROWTH CHARACTERISTICS AND EFFECTS OF UV IRRADIATION

EPA Science Inventory

Symbiodinium spp. Isolates from Stony Coral: Isolation, Growth Characteristics and Effects of UV Irradiation (Abstract). J. Phycol. 37(3):42-43.

Symbiodinium species were isolated from Montipora capitata, Acropora palmata and two field samples of Porites porites. Cultures ...

Bacteria isolated from amoebae/bacteria consortium

DOEpatents

Tyndall, R.L.

1995-05-30

New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

Bacteria isolated from amoebae/bacteria consortium

DOEpatents

Tyndall, Richard L.

1995-01-01

New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

Complex multifractal nature in Mycobacterium tuberculosis genome

PubMed Central

Mandal, Saurav; Roychowdhury, Tanmoy; Chirom, Keilash; Bhattacharya, Alok; Brojen Singh, R. K.

2017-01-01

The mutifractal and long range correlation (C(r)) properties of strings, such as nucleotide sequence can be a useful parameter for identification of underlying patterns and variations. In this study C(r) and multifractal singularity function f(α) have been used to study variations in the genomes of a pathogenic bacteria Mycobacterium tuberculosis. Genomic sequences of M. tuberculosis isolates displayed significant variations in C(r) and f(α) reflecting inherent differences in sequences among isolates. M. tuberculosis isolates can be categorised into different subgroups based on sensitivity to drugs, these are DS (drug sensitive isolates), MDR (multi-drug resistant isolates) and XDR (extremely drug resistant isolates). C(r) follows significantly different scaling rules in different subgroups of isolates, but all the isolates follow one parameter scaling law. The richness in complexity of each subgroup can be quantified by the measures of multifractal parameters displaying a pattern in which XDR isolates have highest value and lowest for drug sensitive isolates. Therefore C(r) and multifractal functions can be useful parameters for analysis of genomic sequences. PMID:28440326

Genotypic Diversity of Phytophthora cinnamomi and P. plurivora in Maryland's Nurseries and Mid-Atlantic Forests.

PubMed

Beaulieu, Justine; Ford, Blaine; Balci, Yilmaz

2017-06-01

Genetic diversity of two Phytophthora spp.-P. cinnamomi (102 isolates), commonly encountered in Maryland nurseries and forests in the Mid-Atlantic United States, and P. plurivora (186 isolates), a species common in nurseries-was characterized using amplified fragment length polymorphism. Expected heterozygosity and other indices suggested a lower level of diversity among P. cinnamomi than P. plurivora isolates. Hierarchical clustering showed P. cinnamomi isolates separated into four clusters, and two of the largest clusters were closely related, containing 80% of the isolates. In contrast, P. plurivora isolates separated into six clusters, one of which included approximately 40% of the isolates. P. plurivora isolates recovered from the environment (e.g., soil and water) were genotypically more diverse than those found causing lesions. For both species, isolate origin (forest versus nursery or among nurseries) was a significant factor of heterozygosity. Clonal groups existed within P. cinnamomi and P. plurivora and included isolates from both forest and nurseries, suggesting that a pathway from nurseries to forests or vice versa exists.

Complex multifractal nature in Mycobacterium tuberculosis genome

NASA Astrophysics Data System (ADS)

Mandal, Saurav; Roychowdhury, Tanmoy; Chirom, Keilash; Bhattacharya, Alok; Brojen Singh, R. K.

2017-04-01

The mutifractal and long range correlation (C(r)) properties of strings, such as nucleotide sequence can be a useful parameter for identification of underlying patterns and variations. In this study C(r) and multifractal singularity function f(α) have been used to study variations in the genomes of a pathogenic bacteria Mycobacterium tuberculosis. Genomic sequences of M. tuberculosis isolates displayed significant variations in C(r) and f(α) reflecting inherent differences in sequences among isolates. M. tuberculosis isolates can be categorised into different subgroups based on sensitivity to drugs, these are DS (drug sensitive isolates), MDR (multi-drug resistant isolates) and XDR (extremely drug resistant isolates). C(r) follows significantly different scaling rules in different subgroups of isolates, but all the isolates follow one parameter scaling law. The richness in complexity of each subgroup can be quantified by the measures of multifractal parameters displaying a pattern in which XDR isolates have highest value and lowest for drug sensitive isolates. Therefore C(r) and multifractal functions can be useful parameters for analysis of genomic sequences.

Antimicrobial susceptibility of Clostridium perfringens isolates of bovine, chicken, porcine, and turkey origin from Ontario.

PubMed

Slavić, Durđa; Boerlin, Patrick; Fabri, Marta; Klotins, Kim C; Zoethout, Jennifer K; Weir, Pat E; Bateman, Debbie

2011-04-01

Antimicrobial susceptibilities and toxin types were determined for 275 Clostridium perfringens isolates collected in Ontario in the spring of 2005. Minimal inhibitory concentrations (MICs) of C. perfringens isolates for 12 antimicrobials used in therapy, prophylaxis, and/or growth promotion of cattle (n = 40), swine (n = 75), turkeys (n = 50), and chickens (n = 100) were determined using the microbroth dilution method. Statistical analyses and MIC distributions showed reduced susceptibility to bacitracin, clindamycin, erythromycin, florfenicol, and tetracycline for some isolates. Reduced susceptibility to bacitracin was identified in chicken (64%) and turkey (60%) isolates. Swine isolates had predominantly reduced susceptibility to clindamycin (28%) and erythromycin (31%), whereas bovine isolates had reduced susceptibility to clindamycin (10%) and florfenicol (10%). Reduced susceptibility to tetracycline was spread across all species. No clear reduced susceptibility, but elevated MIC(50) for virginiamycin was found in chicken isolates in comparison with isolates from other species. Toxin typing revealed that C. perfringens type A is the dominant toxin type isolated in this study across all 4 host species.

Comparison of atypical Brachyspira spp. clinical isolates and classic strains in a mouse model of swine dysentery.

PubMed

Burrough, Eric; Strait, Erin; Kinyon, Joann; Bower, Leslie; Madson, Darin; Schwartz, Kent; Frana, Timothy; Songer, J Glenn

2012-12-07

Multiple Brachyspira spp. can colonize the porcine colon, and the presence of the strongly beta-hemolytic Brachyspira hyodysenteriae is typically associated with clinical swine dysentery. Recently, several Brachyspira spp. have been isolated from the feces of pigs with clinical disease suggestive of swine dysentery, yet these isolates were not identified as B. hyodysenteriae by genotypic or phenotypic methods. This study used a mouse model of swine dysentery to compare the pathogenic potential of seventeen different Brachyspira isolates including eight atypical clinical isolates, six typical clinical isolates, the standard strain of B. hyodysenteriae (B204), and reference strains of Brachyspira intermedia and Brachyspira innocens. Results revealed that strongly beta-hemolytic isolates induced significantly greater cecal inflammation than weakly beta-hemolytic isolates regardless of the genetic identification of the isolate, and that strongly beta-hemolytic isolates identified as 'Brachyspira sp. SASK30446' and B. intermedia by PCR produced lesions indistinguishable from those caused by B. hyodysenteriae in this model. Copyright © 2012 Elsevier B.V. All rights reserved.

Characterization of Salmonella Typhimurium isolates associated with septicemia in swine

PubMed Central

Bergeron, Nadia; Corriveau, Jonathan; Letellier, Ann; Daigle, France; Quessy, Sylvain

2010-01-01

Salmonella Typhimurium is frequently isolated from pigs and may also cause enteric disease in humans. In this study, 33 isolates of S. Typhimurium associated with septicemia in swine (CS) were compared to 33 isolates recovered from healthy animals at slaughter (WCS). The isolates were characterized using phenotyping and genotyping methods. For each isolate, the phage type, antimicrobial resistance, and pulsed-field gel electrophoresis (PFGE) DNA profiles were determined. In addition, the protein profiles of each isolate grown in different conditions were studied by Coomassie Blue-stained sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblot. Various phage types were identified. The phage type PT 104 represented 36.4% of all isolates from septicemic pigs. Resistance to as many as 12 antimicrobial agents, including some natural resistances, was found in isolates from CS and WCS. Many genetic profiles were identified among the PT 104 phage types. Although it was not possible to associate one particular protein with septicemic isolates, several highly immunogenic proteins, present in all virulent isolates and in most isolates from clinically healthy animals, were identified. These results indicated that strains associated with septicemia belong to various genetic lineages that can also be recovered from asymptomatic animals at the time of slaughter. PMID:20357952

Male and female contributions to behavioral isolation in darters as a function of genetic distance and color distance

PubMed Central

Moran, Rachel L.; Zhou, Muchu; Catchen, Julian M.; Fuller, Rebecca C.

2017-01-01

Abstract Determining which reproductive isolating barriers arise first between geographically isolated lineages is critical to understanding allopatric speciation. We examined behavioral isolation among four recently diverged allopatric species in the orangethroat darter clade (Etheostoma: Ceasia). We also examined behavioral isolation between each Ceasia species and the sympatric rainbow darter Etheostoma caeruleum. We asked (1) is behavioral isolation present between allopatric Ceasia species, and how does this compare to behavioral isolation with E. caeruleum, (2) does male color distance and/or genetic distance predict behavioral isolation between species, and (3) what are the relative contributions of female choice, male choice, and male competition to behavioral isolation? We found that behavioral isolation, genetic differentiation, and male color pattern differentiation were present between allopatric Ceasia species. Males, but not females, discerned between conspecific and heterospecific mates. Males also directed more aggression toward conspecific rival males. The high levels of behavioral isolation among Ceasia species showed no obvious pattern with genetic distance or male color distance. However, when the E. caeruleum was included in the analysis, an association between male aggression and male color distance was apparent. We discuss the possibility that reinforcement between Ceasia and E. caeruleum is driving behavioral isolation among allopatric Ceasia species. PMID:28776645

The heterogeneity of socially isolated older adults: a social isolation typology.

PubMed

Machielse, Anja

2015-01-01

Recent statistics show a growing number of older adults who are living alone and are socially isolated. It is against this background that, in recent years, many interventions have been developed to address social isolation among the elderly. Evaluative studies show that most interventions are hardly effective, though. An important reason for this is the heterogeneity of the socially isolated. This article offers insight into this heterogeneity by presenting a typology with different profiles of socially isolated older adults and the intervention implications of this typology. The typology is derived from an extensive qualitative study on socially isolated elderly individuals in the Netherlands. The typology imposes some degree of order to a diversity of circumstances, ambitions, and possibilities of the socially isolated elderly, thereby deepening the understanding of the heterogeneity of this population. The definition of social isolation used in this study starts from a societal angle of incidence, namely the current policy context of Western European welfare states, in which governments emphasize the importance of independence and self-reliance of their citizens. Developed from that perspective, the typology provides a theoretical basis for applying interventions aimed at increasing self-reliance of social isolated elderly. This perspective on social isolation also has consequences for the way in which the effectiveness of interventions to alleviate social isolation is assessed.

Isolation and identification of bacterial pathogen from mastitis milk in Central Java Indonesia

NASA Astrophysics Data System (ADS)

Harjanti, D. W.; Ciptaningtyas, R.; Wahyono, F.; Setiatin, ET

2018-01-01

Mastitis is a multi-etiologic disease of the mammary gland characterized mainly by reduction in milk production and milk quality due to intramammary infection by pathogenic bacteria. Nearly 83% of lactating dairy cows in Indonesia are infected with mastitis in various inflammation degrees. This study was conducted to isolate and identify the pathogen in milk collected from mastitis-infected dairy cows. The study was carried out in ten smallholder dairy farms in Central Java Indonesia based on animal examination, California mastitis test, isolation bacterial pathogens, Gram staining, Catalase and Coagulase test, and identification of bacteria species using Vitek. Bacteriological examination of milk samples revealed 15 isolates where Streptococcus was predominant species (73.3%) and the coagulase negative Staphylococcus species was identified at the least bacteria (26.7%). The Streptococcus bacteria found were Streptococcus uberis (2 isolates), Streptococcus sanguinis(6 isolates), Streptococcus dysgalactiaessp dysgalactiae(1 isolate) , Streptococcus mitis (1 isolate) and Streptococcus agalactiae (1 isolate). The Staphylococcus isolates comprising of Staphylococcus simulans (1 isolate) and Staphylococcus chromogens (3 isolates). Contamination of raw milkwith pathogenic bacteria can cause outbreaks of human disease (milk borne disease). Thus, proper milk processing method that couldinhibit the growth or kill these pathogenic bacteria is important to ensure the safety of milk and milk products.

Detection of meca gene from methicillin resistant staphylococcus aureus isolates of north sumatera

NASA Astrophysics Data System (ADS)

Septiani Nasution, Gabriella; Suryanto, Dwi; Lia Kusumawati, R.

2018-03-01

Methicillin Resistant Staphylococcus aureus (MRSA) is a major pathogen associated with hospital-acquired infections (nosocomial infections). MRSA is a type of S. aureus resistant to the sub-group of beta-lactam antibiotics such as penicillin, cephalosporin, monobactam, and carbapenem. MRSA is resistant because of genetic changes caused by exposure to irrational antibiotic therapy. This study aimed to detect mecA gene in North Sumatra isolates of MRSA and to determine the pattern of antibiotic resistance in S.aureus isolates classified as MRSA by Vitek 2 Compact in the Central Public Hospital Haji Adam Malik, Medan. Samples were 40 isolates of S. aureus classified as MRSA obtained from clinical microbiology specimens. DNA isolation of the isolates was conducted by a method of freeze-thaw cycling. Amplification of mecA gene was done by PCR technique using specific primer for the gene. PCR products were visualized using mini-gel electrophoresis. The results showed that all MRSA isolates showed to have 533 bp band of mecA. Antibiotics test of Vitek 2 Compact showed that despite all isolates were resistant to beta-lactam antibiotics groups; the isolates showed multidrug resistant to other common antibiotics, such as aminoglycosides, macrolides, and fluoroquinolones. However, they were still sensitive to vancomycin (82.5% isolates), linezolid (97.5% isolates), and tigecycline (100% isolates).

Isolation of non-sporing anaerobic rods from infections in children.

PubMed

Brook, I

1996-07-01

From 1974 to 1994, 2033 microbiological specimens from children were submitted for cultures for anaerobic bacteria. Fifty-seven isolates of Bifidobacterium spp. were obtained from 55 (3%) children, 67 isolates of Eubacterium spp. from 65 (3%) children and 41 isolates of Lactobacillus spp. from 40 (2%) children. Most Bifidobacterium isolates were from chronic otitis media, abscesses, peritonitis, aspiration pneumonia and paronychia. Most Eubacterium isolates were from abscesses, peritonitis, decubitus ulcers and bites. Lactobacillus spp. were mainly isolated from abscesses, aspiration pneumonia, bacteraemia and conjunctivitis. Most (> 90%) infections from which these species were isolated were polymicrobial and yielded a mixture of aerobic and anaerobic bacteria. The organisms most commonly isolated with the non-sporing anaerobic gram-positive rods were Peptostreptococcus spp., Bacteroides spp., pigmented Prevotella and Porphyromonas spp., Fusobacterium spp., Staphylococcus aureus and Escherichia coli. Most Bacteroides spp. and E. coli were isolated from intra-abdominal infection and skin and soft tissue infection around the rectal area, whereas most Prevotella, Porphyromonas and Fusobacterium isolates were from oropharyngeal, pulmonary and head and neck sites. The predisposing conditions associated with the isolation of non-sporing anaerobic gram-positive rods were previous surgery, malignancy, steroid therapy and immunodeficiency. Antimicrobial therapy was given to 149 (83%) of the 160 patients, in conjunction with surgical drainage or correction of pathology in 89 (56%).

Echinocandin resistance among Candida isolates at an academic medical centre 2005-15: analysis of trends and outcomes.

PubMed

McCarty, Todd P; Lockhart, Shawn R; Moser, Stephen A; Whiddon, Jennifer; Zurko, Joanna; Pham, Cau D; Pappas, Peter G

2018-02-28

To identify the frequency of micafungin resistance among clinically significant isolates of Candida stored at our institution from 2005 to 2015. Chart review of patients with resistant isolates then informed the clinical setting and outcomes associated with these infections. Clinical Candida isolates had been stored at -80°C in Brucella broth with 20% glycerol from 2005. Isolates were tested using broth microdilution to determine micafungin MICs. All Candida glabrata isolates and all isolates demonstrating decreased susceptibility to micafungin were screened for FKS mutations using a Luminex assay. In total, 3876 Candida isolates were tested for micafungin resistance, including 832 C. glabrata isolates. Of those, 33 isolates from 31 patients were found to have either decreased susceptibility to micafungin and/or an FKS mutation. C. glabrata accounted for the majority of these isolates. While bloodstream infections were found to have a very high mortality rate, isolates from other sites were uncommonly associated with 30-day mortality. Overall resistance rates were very low. Echinocandin resistance in C. glabrata has been increasingly reported but rates at our institution remain very low. We hypothesize that a focus on antifungal stewardship may have led to these observations. Knowledge of local resistance patterns is key to appropriate empirical treatment strategies.

The potential of bacteria isolated from ruminal contents of seaweed-eating North Ronaldsay sheep to hydrolyse seaweed components and produce methane by anaerobic digestion in vitro

PubMed Central

Williams, Allan G; Withers, Susan; Sutherland, Alastair D

2013-01-01

The production of methane biofuel from seaweeds is limited by the hydrolysis of polysaccharides. The rumen microbiota of seaweed-eating North Ronaldsay sheep was studied for polysaccharidic bacterial isolates degrading brown-seaweed polysaccharides. Only nine isolates out of 65 utilized > 90% of the polysaccharide they were isolated on. The nine isolates (eight Prevotella spp. and one Clostridium butyricum) utilized whole Laminaria hyperborea extract and a range of seaweed polysaccharides, including alginate (seven out of nine isolates), laminarin and carboxymethylcellulose (eight out of nine isolates); while two out of nine isolates additionally hydrolysed fucoidan to some extent. Crude enzyme extracts from three of the isolates studied further had diverse glycosidases and polysaccharidase activities; particularly against laminarin and alginate (two isolates were shown to have alginate lyase activity) and notably fucoidan and carageenan (one isolate). In serial culture rumen microbiota hydrolysed a range of seaweed polysaccharides (fucoidan to a notably lesser degree) and homogenates of L. hyperborea, mixed Fucus spp. and Ascophyllum nodosum to produce methane and acetate. The rumen microbiota and isolates represent potential adjunct organisms or enzymes which may improve hydrolysis of seaweed components and thus improve the efficiency of seaweed anaerobic digestion for methane biofuel production. PMID:23170956

Molecular typing, antibiotic resistance, virulence gene and biofilm formation of different Salmonella enterica serotypes.

PubMed

Turki, Yousra; Mehr, Ines; Ouzari, Hadda; Khessairi, Amel; Hassen, Abdennaceur

2014-01-01

Salmonella enterica isolates representing commonly isolated serotypes in Tunisia were analyzed using genotyping and phenotyping methods. ERIC and ITS-PCR applied to 48 Salmonella spp. isolates revealed the presence of 12 and 10 different profiles, respectively. The distribution of profiles among serotypes demonstrated the presence of strains showing an identical fingerprinting pattern. All Salmonella strains used in this study were positive for the sdiA gene. Three Salmonella isolates belonging to serotypes Anatum, Enteritidis and Amsterdam were negative for the invA gene. The spvC gene was detected in thirteen isolates belonging to serotypes Anatum, Typhimurium, Enteritidis, Gallinarum and Montevideo. Antibiotic resistance was frequent among the recovered Salmonella isolates belonging to serotypes Anatum, Typhimurium, Enteritidis, Zanzibar and Derby. The majority of these isolates exhibited resistance to at least two antibiotic families. Four multidrug-resistant isolates were recovered from food animals and poultry products. These isolates exhibited not only resistance to tetracycline, sulphonamides, and ampicillin, but also have shown resistance to fluoroquinolones. Common resistance to nalidixic acid, ciprofloxacin and ofloxacin in two S. Anatum and S. Zanzibar strains isolated from raw meat and poultry was also obtained. Furthermore, wastewater and human isolates exhibited frequent resistance to nalidixic acid and tetracycline. Of all isolates, 33.5% were able to form biofilm.

Yersinia enterocolitica and related species isolated from wildlife in New York State.

PubMed Central

Shayegani, M; Stone, W B; DeForge, I; Root, T; Parsons, L M; Maupin, P

1986-01-01

Fecal specimens for Yersinia screening were obtained from a variety of wild mammals, birds, reptiles, fish, and invertebrates throughout New York State. One specimen from each of 1,426 animals was examined. A total of 148 isolates of Yersinia enterocolitica and related species were obtained from 133 (9.3%) of the animals. Y. enterocolitica was isolated from 100 (7%) of the animals tested, including 81 (10%) of 812 mammals and 19 (3.3%) of 573 birds. Y. intermedia, Y. frederiksenii, and Y. kristensenii were isolated from 39 (2.7%), 5 (0.35%), and 4 (0.28%) animals, respectively. The 81 Y. enterocolitica isolates from mammals belonged to 15 serogroups and included three pathogens: two isolates of typical serogroup 0:8, the "American strain," one from a gray fox (Urocyon cinereoargenteus) and one from a porcupine (Erethizon dorsatum); and one isolate of serogroup 0:3, bacteriophage type IXb, the "Canadian strain," from a gray fox. The most prevalent serogroups recovered from mammals were 0:6,31 (16 isolates) and 0:5,27 (6 isolates). The 19 isolates of Y. enterocolitica from birds belonged to nine serogroups and included one serogroup 0:6,31 isolate from a common grackle (Quiscalus quiscula) and two serogroup 0:5,27 isolates from great horned owls (Bubo virginianus). PMID:3767355

[Isolation of actinobacteria with antibiotic associated with soft coral Nephthea sp].

PubMed

Ma, Liang; Zhang, Wenjun; Zhu, Yiguang; Wu, Zhengchao; Saurav, Kumar; Hang, Hui; Zhang, Changsheng

2013-10-04

The present study aims to isolate and identify actinobacteria associated with the soft coral Nephthea sp., and to isolate natural products from these actinobacteria under the guidance of PCR screening for polyketides synthase (PKS) genes. Eleven selective media were used to isolate actinobacteria associated with the soft coral Nephthea sp. collected from Yongxin Island. The isolated actinobacteria were classified on the basis of phylogenetic tree analysis of their 16S rRNA genes. Degenerated primers targeted on conserved KS (ketoacyl-synthase) domain of type I PKS genes were used to screen for potential isolates. The positive isolates were cultured in three different media to check their producing profiles. One bioactive strain that is rich in metabolites was subjected to larger scale fermentation for isolating bioactive natural products. A total of 20 strains were isolated from Nephthea sp., and were categorized into 3 genera including Streptomyces, Dietzia and Salinospora, among which 18 strains were positive in screening with type I PKS genes. Two bioactive compounds rifamycin S and rifamycin W were isolated and identified from Salinospora arenicola SH04. This is the first report of isolating indigenous marine actinobacteria Salinospora from the soft coral Nephthea sp. It provides an example of isolating bioactive secondary metabolites from cultivable actinobacteria associated with Nephthea sp. by PCR screening.

Diversity and Antimicrobial Activities of Actinobacteria Isolated from Tropical Mangrove Sediments in Malaysia

PubMed Central

Lee, Learn-Han; Zainal, Nurullhudda; Azman, Adzzie-Shazleen; Eng, Shu-Kee; Goh, Bey-Hing; Yin, Wai-Fong; Ab Mutalib, Nurul-Syakima; Chan, Kok-Gan

2014-01-01

The aim of this study was to isolate and identify Actinobacteria from Malaysia mangrove forest and screen them for production of antimicrobial secondary metabolites. Eighty-seven isolates were isolated from soil samples collected at 4 different sites. This is the first report to describe the isolation of Streptomyces, Mycobacterium, Leifsonia, Microbacterium, Sinomonas, Nocardia, Terrabacter, Streptacidiphilus, Micromonospora, Gordonia, and Nocardioides from mangrove in east coast of Malaysia. Of 87 isolates, at least 5 isolates are considered as putative novel taxa. Nine Streptomyces sp. isolates were producing potent antimicrobial secondary metabolites, indicating that Streptomyces isolates are providing high quality metabolites for drug discovery purposes. The discovery of a novel species, Streptomyces pluripotens sp. nov. MUSC 135T that produced potent secondary metabolites inhibiting the growth of MRSA, had provided promising metabolites for drug discovery research. The biosynthetic potential of 87 isolates was investigated by the detection of polyketide synthetase (PKS) and nonribosomal polyketide synthetase (NRPS) genes, the hallmarks of secondary metabolites production. Results showed that many isolates were positive for PKS-I (19.5%), PKS-II (42.5%), and NRPS (5.7%) genes, indicating that mangrove Actinobacteria have significant biosynthetic potential. Our results highlighted that mangrove environment represented a rich reservoir for isolation of Actinobacteria, which are potential sources for discovery of antimicrobial secondary metabolites. PMID:25162061

Diversity and antimicrobial activities of actinobacteria isolated from tropical mangrove sediments in Malaysia.

PubMed

Lee, Learn-Han; Zainal, Nurullhudda; Azman, Adzzie-Shazleen; Eng, Shu-Kee; Goh, Bey-Hing; Yin, Wai-Fong; Ab Mutalib, Nurul-Syakima; Chan, Kok-Gan

2014-01-01

The aim of this study was to isolate and identify Actinobacteria from Malaysia mangrove forest and screen them for production of antimicrobial secondary metabolites. Eighty-seven isolates were isolated from soil samples collected at 4 different sites. This is the first report to describe the isolation of Streptomyces, Mycobacterium, Leifsonia, Microbacterium, Sinomonas, Nocardia, Terrabacter, Streptacidiphilus, Micromonospora, Gordonia, and Nocardioides from mangrove in east coast of Malaysia. Of 87 isolates, at least 5 isolates are considered as putative novel taxa. Nine Streptomyces sp. isolates were producing potent antimicrobial secondary metabolites, indicating that Streptomyces isolates are providing high quality metabolites for drug discovery purposes. The discovery of a novel species, Streptomyces pluripotens sp. nov. MUSC 135(T) that produced potent secondary metabolites inhibiting the growth of MRSA, had provided promising metabolites for drug discovery research. The biosynthetic potential of 87 isolates was investigated by the detection of polyketide synthetase (PKS) and nonribosomal polyketide synthetase (NRPS) genes, the hallmarks of secondary metabolites production. Results showed that many isolates were positive for PKS-I (19.5%), PKS-II (42.5%), and NRPS (5.7%) genes, indicating that mangrove Actinobacteria have significant biosynthetic potential. Our results highlighted that mangrove environment represented a rich reservoir for isolation of Actinobacteria, which are potential sources for discovery of antimicrobial secondary metabolites.

Bacterial isolates from the bryozoan Membranipora membranacea: influence of culture media on isolation and antimicrobial activity.

PubMed

Heindl, Herwig; Thiel, Vera; Wiese, Jutta; Imhoff, Johannes F

2012-03-01

From specimens of the bryozoan Membranipora membranacea collected in the Baltic Sea, bacteria were isolated on four different media, which significantly increased the diversity of the isolated groups. All isolates were classified according to 16S rRNA gene sequence analysis and tested for antimicrobial properties using a panel of five indicator strains and six different media. Each medium featured a unique set of isolated phylotypes, and a phylogenetically diverse collection of isolates was obtained. A total of 96 isolates were assigned to 49 phylotypes and 29 genera. Only one-third of the members of these genera had been isolated previously from comparable sources. The isolates were affiliated with Alpha- and Gammaproteobacteria, Bacilli, and Actinobacteria. A comparable large portion of up to 22 isolates, i.e., 15 phylotypes, probably represent new species. Likewise, 47 isolates (approximately 50%) displayed antibiotic activities, mostly against grampositive indicator strains. Of the active strains, 63.8 % had antibiotic traits only on one or two of the growth media, whereas only 12.7 % inhibited growth on five or all six media. The application of six different media for antimicrobial testing resulted in twice the number of positive hits as obtained with only a single medium. The use of different media for the isolation of bacteria as well as the variation of media considered suitable for the production of antibiotic substances significantly enhanced both the number of isolates obtained and the proportion of antibiotic active cultures. Thus the approach described herein offers an improved strategy in the search for new antibiotic compounds.

Phenotype and genotype of Escherichia coli isolated from pigs with postweaning diarrhea in Hungary.

PubMed Central

Nagy, B; Casey, T A; Moon, H W

1990-01-01

A total of 205 Escherichia coli isolates from 88 diarrheal weanling (4- to 10-week-old) pigs from 59 farms were tested by slide agglutination for K88, K99, F41, and 987P antigens. K88 antigen was detected in 61% of the isolates representing 60% of the pigs and 56% of the farms. K88 antigen was associated with serogroup O149 and 91% of the K88+ isolates. K99, F41, and 987P were not detected. Of the K88- isolates, 70 were additionally tested by colony hybridization with DNA probes for adherence factors K88, K99, 987P, and F41 and for enterotoxin genes STaP, STaH, STb, and LT and by Vero cell assay for verotoxins (VT). The 70 K88- isolates could be divided into three categories: LT-, VT-, STaP+, and/or STb+ (34 isolates); LT-, STaP+, STb+, and/or VT+ (17 isolates); and nontoxigenic (19 isolates). Only one of the K88- isolates carried a known adherence factor (987P) detectable with DNA probes. Most of the STaP+ and STb+ isolates belonged to O groups O141, O147, and O157. All but 1 of the 17 VT+ isolates belonged to O groups O138, O139, O141, and O149. Only three of the VT+ strains were isolated from pigs with edema disease. We concluded that 73% of the K88- isolates had the capability to produce enterotoxins or VT that could have contributed to weanling pig diarrhea. PMID:1970575

A molecular surveillance reveals the prevalence of Vibrio cholerae O139 isolates in China from 1993 to 2012.

PubMed

Zhang, Ping; Zhou, Haijian; Diao, Baowei; Li, Fengjuan; Du, Pengcheng; Li, Jie; Kan, Biao; Morris, J Glenn; Wang, Duochun

2014-04-01

Vibrio cholerae serogroup O139 was first identified in 1992 in India and Bangladesh, in association with major epidemics of cholera in both countries; cases were noted shortly thereafter in China. We characterized 211 V. cholerae O139 isolates that were isolated at multiple sites in China between 1993 and 2012 from patients (n = 92) and the environment (n = 119). Among clinical isolates, 88 (95.7%) of 92 were toxigenic, compared with 47 (39.5%) of 119 environmental isolates. Toxigenic isolates carried the El Tor CTX prophage and toxin-coregulated pilus A gene (tcpA), as well as the Vibrio seventh pandemic island I (VSP-I) and VSP-II. Among a subset of 42 toxigenic isolates screened by multilocus sequence typing (MLST), all were in the same sequence type as a clinical isolate (MO45) from the original Indian outbreak. Nontoxigenic isolates, in contrast, generally lacked VSP-I and -II, and fell within 13 additional sequence types in two clonal complexes distinct from the toxigenic isolates. In further pulsed-field gel electrophoresis (PFGE) (with NotI digestion) studies, toxigenic isolates formed 60 pulsotypes clustered in one group, while the nontoxigenic isolates formed 43 pulsotypes which clustered into 3 different groups. Our data suggest that toxigenic O139 isolates from widely divergent geographic locations, while showing some diversity, have maintained a relatively tight clonal structure across a 20-year time span. Nontoxigenic isolates, in contrast, exhibited greater diversity, with multiple clonal lineages, than did their toxigenic counterparts.

Morphological and Inter Simple Sequence Repeat (ISSR) markers analyses of Corynespora cassiicola isolates from rubber plantations in Malaysia.

PubMed

Nghia, Nguyen Anh; Kadir, Jugah; Sunderasan, E; Puad Abdullah, Mohd; Malik, Adam; Napis, Suhaimi

2008-10-01

Morphological features and Inter Simple Sequence Repeat (ISSR) polymorphism were employed to analyse 21 Corynespora cassiicola isolates obtained from a number of Hevea clones grown in rubber plantations in Malaysia. The C. cassiicola isolates used in this study were collected from several states in Malaysia from 1998 to 2005. The morphology of the isolates was characteristic of that previously described for C. cassiicola. Variations in colony and conidial morphology were observed not only among isolates but also within a single isolate with no inclination to either clonal or geographical origin of the isolates. ISSR analysis delineated the isolates into two distinct clusters. The dendrogram created from UPGMA analysis based on Nei and Li's coefficient (calculated from the binary matrix data of 106 amplified DNA bands generated from 8 ISSR primers) showed that cluster 1 encompasses 12 isolates from the states of Johor and Selangor (this cluster was further split into 2 sub clusters (1A, 1B), sub cluster 1B consists of a unique isolate, CKT05D); while cluster 2 comprises of 9 isolates that were obtained from the other states. Detached leaf assay performed on selected Hevea clones showed that the pathogenicity of representative isolates from cluster 1 (with the exception of CKT05D) resembled that of race 1; and isolates in cluster 2 showed pathogenicity similar to race 2 of the fungus that was previously identified in Malaysia. The isolate CKT05D from sub cluster 1B showed pathogenicity dissimilar to either race 1 or race 2.

Identification of a novel Lymantria dispar nucleopolyhedrovirus mutant that exhibits abnormal polyhedron formation and virion occlusion.

PubMed

Slavicek, J M; Mercer, M J; Pohlman, D; Kelly, M E; Bischoff, D S

1998-07-01

In previous studies on the formation of Lymantria dispar nuclear polyhedrosis virus (LdMNPV) few polyhedra (FP) mutants, several polyhedron formation mutants (PFM) were identified that appeared to be unique. These viral mutants are being characterized to investigate the processes of polyhedron formation and virion occlusion. LdMNPV isolate PFM-1 is one of these mutants, and is described in this report. Genetic techniques were used to determine if isolate PFM-1 contained a mutation in the polyhedrin or 25K FP gene. Wild-type viruses were recovered after coinfection of Ld652Y cells with isolate PFM-1 and a FP mutant, and with isolates PFM-1 and PFM-C (isolate PFM-C contains a mutation in the polyhedrin gene). These viruses were analyzed by genomic restriction endonuclease digestion and found to be chimeras of the original PFMs used in the coinfections. Marker rescue studies mapped the mutation in isolate PFM-1 to a genomic region that does not include the polyhedrin or 25K FP genes. Isolate PFM-1 produced approximately 14-fold fewer polyhedra than LdMNPV isolate A21-MPV, an isolate that produces wild-type levels of polyhedra, and approximately 2-fold more polyhedra compared to the FP isolate 122-2. Polyhedra generated by isolate PFM-1 were normal in size and shape but contained very few viral nucleocapsids. The same amount of budded virus (BV) was released from cells infected with isolates PFM-1 and A21-MPV. In contrast, isolate 122-2 yielded significantly more BV than isolates PFM-1 and A21-MPV.

Antibiotic Resistance Patterns of Pseudomonas spp. Isolated from the River Danube

PubMed Central

Kittinger, Clemens; Lipp, Michaela; Baumert, Rita; Folli, Bettina; Koraimann, Günther; Toplitsch, Daniela; Liebmann, Astrid; Grisold, Andrea J.; Farnleitner, Andreas H.; Kirschner, Alexander; Zarfel, Gernot

2016-01-01

Spread and persistence of antibiotic resistance pose a severe threat to human health, yet there is still lack of knowledge about reservoirs of antibiotic resistant bacteria in the environment. We took the opportunity of the Joint Danube Survey 3 (JDS3), the world's biggest river research expedition of its kind in 2013, to analyse samples originating from different sampling points along the whole length of the river. Due to its high clinical relevance, we concentrated on the characterization of Pseudomonas spp. and evaluated the resistance profiles of Pseudomonas spp. which were isolated from eight sampling points. In total, 520 Pseudomonas isolates were found, 344 (66.0%) isolates were identified as Pseudomonas putida, and 141 (27.1%) as Pseudomonas fluorescens, all other Pseudomonas species were represented by less than five isolates, among those two P. aeruginosa isolates. Thirty seven percent (37%) of all isolated Pseudomonas species showed resistance to at least one out of 10 tested antibiotics. The most common resistance was against meropenem (30.4%/158 isolates) piperacillin/tazobactam (10.6%/55 isolates) and ceftazidime (4.2%/22 isolates). 16 isolates (3.1%/16 isolates) were multi-resistant. For each tested antibiotic at least one resistant isolate could be detected. Sampling points from the upper stretch of the River Danube showed more resistant isolates than downriver. Our results suggest that antibiotic resistance can be acquired by and persists even in Pseudomonas species that are normally not in direct contact with humans. A possible scenario is that these bacteria provide a reservoir of antibiotic resistance genes that can spread to related human pathogens by horizontal gene transfer. PMID:27199920

Diversity among strains of Pseudomonas aeruginosa from manure and soil, evaluated by multiple locus variable number tandem repeat analysis and antibiotic resistance profiles.

PubMed

Youenou, Benjamin; Brothier, Elisabeth; Nazaret, Sylvie

2014-01-01

The results of a multiple locus variable number of tandem repeat (VNTR) analysis (MLVA)-based study designed to understand the genetic diversity of soil and manure-borne Pseudomonas aeruginosa isolates, and the relationship between these isolates and a set of clinical and environmental isolates, are hereby reported. Fifteen described VNTR markers were first selected, and 62 isolates recovered from agricultural and industrial soils in France and Burkina Faso, and from cattle and horse manure, along with 26 snake-related isolates and 17 environmental and clinical isolates from international collections, were genotyped. Following a comparison with previously published 9-marker MLVA schemes, an optimal 13-marker MLVA scheme (MLVA13-Lyon) was identified that was found to be the most efficient, as it showed high typability (90%) and high discriminatory power (0.987). A comparison of MLVA with PFGE for typing of the snake-related isolates confirmed the MLVA13-Lyon scheme to be a robust method for quickly discriminating and inferring genetic relatedness among environmental isolates. The 62 isolates displayed wide diversity, since 41 MLVA types (i.e. MTs) were observed, with 26 MTs clustered in 10 MLVA clonal complexes (MCs). Three and eight MCs were found among soil and manure isolates, respectively. Only one MC contained both soil and manure-borne isolates. No common MC was observed between soil and manure-borne isolates and the snake-related or environmental and clinical isolates. Antibiotic resistance profiles were performed to determine a potential link between resistance properties and the selective pressure that might be present in the various habitats. Except for four soil and manure isolates resistant to ticarcillin and ticarcillin/clavulanic acid and one isolate from a hydrocarbon-contaminated soil resistant to imipenem, all environmental isolates showed wild-type antibiotic profiles. Copyright © 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

[Identification of lactic acid bacteria in commercial yogurt and their antibiotic resistance].

PubMed

Qin, Yuxuan; Li, Jing; Wang, Qiuya; Gao, Kexin; Zhu, Baoli; Lv, Na

2013-08-04

To identify lactic acid bacteria (LAB) in commercial yogurts and investigate their antibiotic resistance. LABs were cultured from 5 yogurt brands and the isolates were identified at the species level by 16S rRNA sequence. Genotyping was performed by repetitive extragenic palindromic PCR (rep-PCR). The sensitivity to 7 antibiotics was tested for all LAB isolates by Kirby-Bauer paper diffusion (K-B method). Meanwhile, 9 antibiotic resistance genes (ARGs), including erythromycin resistance genes (ermA and ermB) and tetracycline resistance genes (tetM, tetK, tetS, tetQ, tetO, tetL and tetW), were detected by PCR amplification in the identified LAB isolates. The PCR products were confirmed by sequencing. Total 100 LABs were isolated, including 23 Lactobacillus delbrueckii ssp. bulgaricus, 26 Lactobacillus casei, 30 Streptococcus thermophilus, 5 Lactobacillus acidophilus, 6 Lactobacillus plantarum, and 10 Lactobacillus paracasei. The drug susceptibility test shows that all 100 isolates were resistant to gentamicin and streptomycin, 42 isolates were resistant to vancomycin, and on the contrary all were sensitive to cefalexin, erythromycin, tetracycline and oxytetracycline. Moreover, 5 ARGs were found in the 28 sequencing confirmed isolates, ermB gene was detected in 8 isolates, tet K in 4 isolates, tetL in 2 isolates, tetM in 4 isolates, tetO in 2 isolates. erm A, tet S, tet Q and tet W genes were not detected in the isolates. Antibiotic resistance genes were found in 53.57% (15/28) sequenced isolates, 2 -3 antibiotic resistance genes were detected in 4 isolates of L. delbrueckii ssp. bulgaricus. Some LABs were not labeled in commercial yogurt products. Antibiotic resistance genes tend to be found in the starter culture of L. delbrueckii ssp. Bulgaricus and S. thermophilus. All the LAB isolates were sensitive to erythromycin and tetracycline, even though some carried erythromycin and/or tetracycline resistance genes. We proved again that LAB could carry antibiotic resistance gene(s) though it is sensitive to antibiotics.

Characterisation of nasal Staphylococcus delphini and Staphylococcus pseudintermedius isolates from healthy donkeys in Tunisia.

PubMed

Gharsa, H; Slama, K Ben; Gómez-Sanz, E; Gómez, P; Klibi, N; Zarazaga, M; Boudabous, A; Torres, C

2015-07-01

Staphylococcus intermedius group (SIG) bacteria can colonise the nares of some animals but are also emerging pathogens in humans and animals. To analyse SIG nasal carriage in healthy donkeys destined for food consumption in Tunisia and to characterise recovered isolates. Nasal swabs from 100 healthy donkeys were tested for SIG recovery, and isolates were identified by biochemical and molecular methods. Antimicrobial susceptibility of isolates was tested and detection of antimicrobial resistance and virulence genes was performed. Isolates were typed at the clonal level by multilocus sequence typing and SmaI pulsed-field gel electrophoresis. Staphylococcus delphini and Staphylococcus pseudintermedius (included in SIG) were obtained in 19% and 2% of the tested samples, respectively, and one isolate per sample was characterised. All isolates were meticillin susceptible and mecA negative. Most S. delphini and S. pseudintermedius isolates showed susceptibility to all antimicrobials tested, with the exception of 2 isolates resistant to tetracycline (tet(M) gene) or fusidic acid. The following toxin genes were identified (percentage of isolates): lukS-I (100%), lukF-I (9.5%), siet (100%), se-int (90%), seccanine (19%) and expA (9.5%). Thirteen different pulsed-field gel electrophoresis profiles were identified among the 21 SIG isolates. Additionally, the following 9 different sequence types (STs) were detected by multilocus sequence typing, 6 of them new: ST219 (6 isolates), ST12 (5 isolates), ST220 (3 isolates), ST13, ST50, ST193, ST196, ST218 and ST221 (one isolate each). Staphylococcus delphini and S. pseudintermedius are common nasal colonisers of donkeys, generally susceptible to the antimicrobials tested; nevertheless, these SIG isolates contain virulence genes, including the recently described exfoliative gene (expA) and several enterotoxin genes, with potential implications for public health. This is the first description of S. delphini in Tunisia. The Summary is available in Chinese - see Supporting information. © 2014 EVJ Ltd.

Molecular Identification, Antifungal Susceptibility Profile, and Biofilm Formation of Clinical and Environmental Rhodotorula Species Isolates

PubMed Central

Nunes, Jorge Meneses; Bizerra, Fernando César; Ferreira, Renata Carmona e

2013-01-01

Rhodotorula species are emergent fungal pathogens capable of causing invasive infections, primarily fungemia. They are particularly problematic in immunosuppressed patients when using a central venous catheter. In this study, we evaluated the species distribution of 51 clinical and 8 environmental Rhodotorula species isolates using the ID32C system and internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing and biofilm formation capability using a crystal violet staining assay were performed. Using ITS sequencing as the gold standard, the clinical isolates were identified as follows: 44 R. mucilaginosa isolates, 2 R. glutinis isolates, 2 R. minuta isolates, 2 R. dairenensis isolates, and 1 Rhodosporidium fluviale isolate. The environmental isolates included 7 R. mucilaginosa isolates and 1 R. slooffiae isolate. Using the ID32C system, along with a nitrate assimilation test, only 90.3% of the isolates tested were correctly identified. In the biofilm formation assay, R. mucilaginosa and R. minuta exhibited greater biofilm formation ability compared to the other Rhodotorula species; the clinical isolates of R. mucilaginosa showed greater biofilm formation compared to the environmental isolates (P = 0.04). Amphotericin B showed good in vitro activity (MIC ≤ 1 μg/ml) against planktonic cells, whereas voriconazole and posaconazole showed poor activity (MIC50/MIC90, 2/4 μg/ml). Caspofungin and fluconazole MICs were consistently high for all isolates tested (≥64 μg/ml and ≥ 4 μg/ml, respectively). In this study, we emphasized the importance of molecular methods to correctly identify Rhodotorula species isolates and non-R. mucilaginosa species in particular. The antifungal susceptibility profile reinforces amphotericin B as the antifungal drug of choice for the treatment of Rhodotorula infections. To our knowledge, this is the first study evaluating putative differences in the ability of biofilm formation among different Rhodotorula species. PMID:23114761

Molecular identification, antifungal susceptibility profile, and biofilm formation of clinical and environmental Rhodotorula species isolates.

PubMed

Nunes, Jorge Meneses; Bizerra, Fernando César; Ferreira, Renata Carmona E; Colombo, Arnaldo Lopes

2013-01-01

Rhodotorula species are emergent fungal pathogens capable of causing invasive infections, primarily fungemia. They are particularly problematic in immunosuppressed patients when using a central venous catheter. In this study, we evaluated the species distribution of 51 clinical and 8 environmental Rhodotorula species isolates using the ID32C system and internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing and biofilm formation capability using a crystal violet staining assay were performed. Using ITS sequencing as the gold standard, the clinical isolates were identified as follows: 44 R. mucilaginosa isolates, 2 R. glutinis isolates, 2 R. minuta isolates, 2 R. dairenensis isolates, and 1 Rhodosporidium fluviale isolate. The environmental isolates included 7 R. mucilaginosa isolates and 1 R. slooffiae isolate. Using the ID32C system, along with a nitrate assimilation test, only 90.3% of the isolates tested were correctly identified. In the biofilm formation assay, R. mucilaginosa and R. minuta exhibited greater biofilm formation ability compared to the other Rhodotorula species; the clinical isolates of R. mucilaginosa showed greater biofilm formation compared to the environmental isolates (P = 0.04). Amphotericin B showed good in vitro activity (MIC ≤ 1 μg/ml) against planktonic cells, whereas voriconazole and posaconazole showed poor activity (MIC(50)/MIC(90), 2/4 μg/ml). Caspofungin and fluconazole MICs were consistently high for all isolates tested (≥64 μg/ml and ≥ 4 μg/ml, respectively). In this study, we emphasized the importance of molecular methods to correctly identify Rhodotorula species isolates and non-R. mucilaginosa species in particular. The antifungal susceptibility profile reinforces amphotericin B as the antifungal drug of choice for the treatment of Rhodotorula infections. To our knowledge, this is the first study evaluating putative differences in the ability of biofilm formation among different Rhodotorula species.

Cryptococcus gattii VGIII Isolates Causing Infections in HIV/AIDS Patients in Southern California: Identification of the Local Environmental Source as Arboreal

PubMed Central

Springer, Deborah J.; Billmyre, R. Blake; Filler, Elan E.; Voelz, Kerstin; Pursall, Rhiannon; Mieczkowski, Piotr A.; Larsen, Robert A.; Dietrich, Fred S.; May, Robin C.; Filler, Scott G.; Heitman, Joseph

2014-01-01

Ongoing Cryptococcus gattii outbreaks in the Western United States and Canada illustrate the impact of environmental reservoirs and both clonal and recombining propagation in driving emergence and expansion of microbial pathogens. C. gattii comprises four distinct molecular types: VGI, VGII, VGIII, and VGIV, with no evidence of nuclear genetic exchange, indicating these represent distinct species. C. gattii VGII isolates are causing the Pacific Northwest outbreak, whereas VGIII isolates frequently infect HIV/AIDS patients in Southern California. VGI, VGII, and VGIII have been isolated from patients and animals in the Western US, suggesting these molecular types occur in the environment. However, only two environmental isolates of C. gattii have ever been reported from California: CBS7750 (VGII) and WM161 (VGIII). The incongruence of frequent clinical presence and uncommon environmental isolation suggests an unknown C. gattii reservoir in California. Here we report frequent isolation of C. gattii VGIII MATα and MAT a isolates and infrequent isolation of VGI MATα from environmental sources in Southern California. VGIII isolates were obtained from soil debris associated with tree species not previously reported as hosts from sites near residences of infected patients. These isolates are fertile under laboratory conditions, produce abundant spores, and are part of both locally and more distantly recombining populations. MLST and whole genome sequence analysis provide compelling evidence that these environmental isolates are the source of human infections. Isolates displayed wide-ranging virulence in macrophage and animal models. When clinical and environmental isolates with indistinguishable MLST profiles were compared, environmental isolates were less virulent. Taken together, our studies reveal an environmental source and risk of C. gattii to HIV/AIDS patients with implications for the >1,000,000 cryptococcal infections occurring annually for which the causative isolate is rarely assigned species status. Thus, the C. gattii global health burden could be more substantial than currently appreciated. PMID:25144534

21 CFR 870.2600 - Signal isolation system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Signal isolation system. 870.2600 Section 870.2600...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2600 Signal isolation system. (a) Identification. A signal isolation system is a device that electrically isolates the patient...

21 CFR 870.2600 - Signal isolation system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Signal isolation system. 870.2600 Section 870.2600...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2600 Signal isolation system. (a) Identification. A signal isolation system is a device that electrically isolates the patient...

21 CFR 870.2600 - Signal isolation system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Signal isolation system. 870.2600 Section 870.2600...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2600 Signal isolation system. (a) Identification. A signal isolation system is a device that electrically isolates the patient...

Total main rotor isolation system analysis

NASA Technical Reports Server (NTRS)

Sankewitsch, V.

1981-01-01

Requirements, preliminary design, and verification procedures for a total main rotor isolation system at n/rev are presented. The fuselage is isolated from the vibration inducing main rotor at one frequency in all degrees of freedom by four antiresonant isolation units. Effects of parametric variations on isolation system performance are evaluated.

Mechanism of Flagellar Vaccine Protection Related to Pseudomonas Pathogenesis in Trauma Burns

DTIC Science & Technology

1989-01-19

differentiated by the indirect fluorescent-antibody and aglutination techniques 16). GNB. general clinical non-bum isolate; F. folliculitis isolate; CF...128.000(+ -, 256.000 - 5 12 000 n -s. GNB. general clinical non-burn isolate. F. folliculitis isolate. CF. ,:ystic fibrosis isolate. N R, not reactive

The Prisoner of War: Coping with the Stress of Isolation

DTIC Science & Technology

1974-12-01

HUNTER Social isolation produces stiess, and although persistence of effects in slimt experimental isolations may last only a matter of hours or days...character of the stresses of captivity "severely limits inferences about the etiologic role of specific components; e.g., malnutrition, social isolation... social ’ isolation. Suedfcld IT has pointed out that the amount of research on the effects of social isolation per se is very small, and that most

Occurrence and antimicrobial resistance of Salmonella strains from food of animal origin in southern Italy.

PubMed

Proroga, Yolande T R; Capuano, Federico; Carullo, Maria Rosaria; La Tela, Immacolata; Capparelli, Rosanna; Barco, Lisa; Pasquale, Vincenzo

2016-01-01

Six hundred fourteen strains of Salmonella enterica were isolated from 16,926 samples of food of animal origin collected in southern Italy from 2003 to 2012. The isolates were identified, serotyped, and challenged against 15 antibiotics according to the protocol defined at national level for veterinary isolates of Salmonella (EnterVet surveillance network). Salmonella serotypes Typhimurium, Hadar, Enteritidis, Derby, and 4,[5],12:i:- were those most frequently isolated. The widest resistances were recorded towards sulfonamides (69 % of the isolates), trimethoprim-sulfamethoxazole (52 % of the isolates), and tetracycline (51 % of the isolates). The rate of multidrug resistance of the isolates decreased significantly from the first 5 years of the study period (82.6 %) to the last 5 years (54.3 %).

Genome sequence analysis of five Canadian isolates of strawberry mottle virus reveals extensive intra-species diversity and a longer RNA2 with increased coding capacity compared to a previously characterized European isolate.

PubMed

Bhagwat, Basdeo; Dickison, Virginia; Ding, Xinlun; Walker, Melanie; Bernardy, Michael; Bouthillier, Michel; Creelman, Alexa; DeYoung, Robyn; Li, Yinzi; Nie, Xianzhou; Wang, Aiming; Xiang, Yu; Sanfaçon, Hélène

2016-06-01

In this study, we report the genome sequence of five isolates of strawberry mottle virus (family Secoviridae, order Picornavirales) from strawberry field samples with decline symptoms collected in Eastern Canada. The Canadian isolates differed from the previously characterized European isolate 1134 in that they had a longer RNA2, resulting in a 239-amino-acid extension of the C-terminal region of the polyprotein. Sequence analysis suggests that reassortment and recombination occurred among the isolates. Phylogenetic analysis revealed that the Canadian isolates are diverse, grouping in two separate branches along with isolates from Europe and the Americas.

Characterization of isolates of meloidogyne from rice-wheat production fields in Nepal.

PubMed

Pokharel, Ramesh R; Abawi, George S; Zhang, Ning; Duxbury, John M; Smart, Christine D

2007-09-01

Thirty-three isolates of root-knot nematode were recovered from soil samples from rice-wheat fields in Nepal and maintained on rice cv. BR 11. The isolates were characterized using morphology, host range and DNA sequence analyses in order to ascertain their identity. Results indicated phenotypic similarity (juvenile measurements, perennial pattern, host range and gall shape) of the Nepalese isolates with Meloidogyne graminicola, with minor variations. The rice varieties LA 110 and Labelle were susceptible to all of the Nepalese isolates, but differences in the aggressiveness of the isolates were observed. Phylogenetic analyses based on the sequences of partial internal transcribed spacer (ITS) of the rRNA genes indicated that all Nepalese isolates formed a distinct clade with known isolates of M. graminicola with high bootstrap support. Furthermore, two groups were identified within the M. graminicola clade. No correlation between ITS haplotype and aggressiveness or host range was found among the tested isolates.

Tiamulin resistance in porcine Brachyspira pilosicoli isolates.

PubMed

Pringle, M; Landén, A; Franklin, A

2006-02-01

There are few studies on antimicrobial susceptibility of Brachyspira pilosicoli, therefore this study was performed to investigate the situation among isolates from pigs. The tiamulin and tylosin susceptibility was determined by broth dilution for 93 and 86 porcine B. pilosicoli isolates, respectively. The isolates came from clinical samples taken in Swedish pig herds during the years 2002 and 2003. The tylosin minimal inhibitory concentration (MIC) was >16 microg/ml for 50% (n=43) of the isolates tested. A tiamulin MIC >2 microg/ml was obtained for 14% (n=13) of the isolates and these were also tested against doxycycline, salinomycin, valnemulin, lincomycin and aivlosin. For these isolates the susceptibility to salinomycin and doxycycline was high but the MICs for aivlosin varied. The relationship between the 13 tiamulin resistant isolates was analyzed by pulsed-field gel electrophoresis (PFGE). Among the 13 isolates 10 different PFGE patterns were identified.

Molecular characterization of Bacillus thuringiensis isolated from diverse habitats of India.

PubMed

Patel, Ketan D; Chudasama, Chaitanyasinh J; Ingle, Sanjay S

2012-08-01

Bacillus thuringiensis (Bt) strains were isolated from 94 samples from different geographical regions. Novel types of crystalline inclusion bodies were observed from some of the isolates. Crystalline inclusions of bipyramidal, spherical and cuboidal morphology were found produced by most of the isolates. Isolate GS12 showed crystal on one side of spore while isolate GM108 formed crystals on both termini of spore. Isolate GN31 produced large sized bipyramidal crystals. SDS-PAGE analysis of the spore crystal suspension showed major protein bands in the range of 29 and 140 kDa. Two new serovars of Bt viz. GS4 and GN24 having H3abce and H3ab serotype respectively were isolated. Toxicity comparable to the reference strain Bacillus thuringiensis subs. kurstaki (Btk) HD-1 was observed for the isolates GM20, GM17 and MP3 against larvae of Helicoverpa armigera. Some of the isolates harboring cry genes like cry1Ac and cry2 did not show any toxicity towards H. armigera while most of the isolates were harboring cry1, cry1Ac and cry2 gene. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Pseudomonas spp on infection of Peronosporaparasitica (Pers. Fr), the pathogen of downy mildew on Chinese cabbage

NASA Astrophysics Data System (ADS)

Damiri, N.; Mulawarman; Umayah, A.; Agustin, S. E.; Rahmiyah, M.

2018-01-01

This research was conducted to study the effect of the application of Pseudomonasspp on infection of Peronosporaparasitica (Pers. Fr), the pathogen of Downy mildew on Chinese cabbage. The research was conducted in the laboratory and greenhouse Department of Plant Pests and Diseases Faculty of Agriculture Sriwijaya University, Inderalaya, OganIlir South Sumatra Indonesia. The research was conducted in the laboratory and greenhouse Department of Plant Pests and Diseases Faculty of Agriculture Sriwijaya University, Inderalaya, Ogan Ilir South Sumatra Indonesia. The research was conducted using Completely Randomized Design with ten treatments including control. ie: isolate A, Isolate B, isolate C, isolate D, isolate E, isolate F, isolate G, isolate H, isolate I and control. Each treatment consists of four replications. Results of the study showed that the application of Pseudomonas spp. can suppress the infection of P. parasitica on Chinese cabbage. The lowest disease intensity was shown by treatment C (isolate Pseudomonas sp.) which was significantly different from control. The best treatment in suppressing disease severity of downy mildew on chinese cabbage was isolate H which had disease severity of 37.07 percent, which was significantly different from control and other treatment.

Comparative Study on Antibiotic Resistance and DNA Profiles of Salmonella enterica Serovar Typhimurium Isolated from Humans, Retail Foods, and the Environment in Shanghai, China.

PubMed

Zhang, Zengfeng; Cao, Chenyang; Liu, Bin; Xu, Xuebin; Yan, Yanfei; Cui, Shenghui; Chen, Sheng; Meng, Jianghong; Yang, Baowei

2018-05-09

We characterized antibiotic resistance profiles, antibiotic resistance-associated genes, and pulsed-field gel electrophoresis (PFGE) patterns of 145 Salmonella enterica serotype Typhimurium isolates from human infections and retail foods that were possibly responsible for salmonellosis outbreaks from 2008 to 2012 in Shanghai, China. Resistance to at least three antibiotics was found in 66.7% of chicken isolates, 76.5% of duck isolates, 77.8% of pork isolates, and 80.5% of human isolates. Seven antibiotic resistance phenotypes were detected in chicken isolates, 16 in pork isolates, 17 in duck isolates, and 50 in human isolates. No significant difference (p > 0.05) was found between Salmonella isolates derived from human salmonellosis and from retail foods in terms of the percent resistance of ampicillin, amoxicillin/clavulanic acid, ceftiofur, ceftriaxone, nalidixic acid, chloramphenicol, gentamicin, kanamycin, streptomycin, tetracycline, sulfisoxazole, and sulfamethoxazole/trimethoprim. PFGE using XbaI and BlnI showed that some Salmonella isolates recovered from human infections and retail foods had same or highly similar genetic profile. Same or similar antibiotic resistance profiles, antibiotic resistance associated genes (i.e., qnrA, qnrB, qnrS, aac(6')-Ib, and oqxAB), gene cassettes (i.e., aadA2, dfrA12-aadA2, and aadA1), and mutations were detected in those isolates that exhibited high genetic similarities. These findings highlighted the frequent presence of Salmonella Typhimurium in retail chicken, pork, duck, and humans.

Distribution and Genetic Variability of Fusarium oxysporum Associated with Tomato Diseases in Algeria and a Biocontrol Strategy with Indigenous Trichoderma spp.

PubMed

Debbi, Ali; Boureghda, Houda; Monte, Enrique; Hermosa, Rosa

2018-01-01

Fifty fungal isolates were sampled from diseased tomato plants as result of a survey conducted in seven tomato crop areas in Algeria from 2012 to 2015. Morphological criteria and PCR-based identification, using the primers PF02 and PF03, assigned 29 out of 50 isolates to Fusarium oxysporum ( Fo ). The banding patterns amplified for genes SIX1, SIX3 and SIX4 served to identify races 2 and 3 of Fo f. sp. lycopersici (FOL), and Fo f. sp. radicis lycopersici (FORL) among the Algerian isolates. All FOL isolates showed pathogenicity on the susceptible tomato cv. "Super Marmande," while nine of out 10 Algerian FORL isolates were pathogenic on tomato cv. "Rio Grande." Inter simple sequence repeat (ISSR) fingerprints showed high genetic diversity among Algerian Fo isolates. Seventeen Algerian Trichoderma isolates were also obtained and assigned to the species T. asperellum (12 isolates), T. harzianum (four isolates) and T. ghanense (one isolate) based on ITS and tef1 α gene sequences. Different in vitro tests identified the antagonistic potential of native Trichoderma isolates against FORL and FOL. Greenhouse biocontrol assays performed on "SM" tomato plants with T. ghanense T8 and T. asperellum T9 and T17, and three Fo isolates showed that isolate T8 performed well against FORL and FOL. This finding was based on an incidence reduction of crown and root rot and Fusarium wilt diseases by 53.1 and 48.3%, respectively.

Virulence genes and plasmid profiles in Rhodococcus equi isolates from domestic pigs and wild boars (Sus scrofa) in Brazil.

PubMed

Ribeiro, Márcio Garcia; Takai, Shinji; Guazzelli, Alessandro; Lara, Gustavo Henrique Batista; da Silva, Aristeu Vieira; Fernandes, Marta Catarina; Condas, Larissa Anuska Zeni; Siqueira, Amanda Keller; Salerno, Tatiana

2011-12-01

The virulence genes and plasmid profiles of 23 Rhodococcus equi isolates from 258 lymph nodes from domestic pigs (129 nodes with lesions and 129 without lesions) and 120 lymph nodes from slaughtered wild boars (60 nodes with lesions and 60 without) were characterized. R. equi was obtained from 19 lymph nodes of domestic pigs, 17 with, and two without lesions, and from four lymph nodes with lesions, from wild boars. The 23 isolates were tested for the presence of vapA and vapB genes, responsible for the 15-17 and 20 kDa virulence-associated proteins, respectively, by PCR in order to characterize as virulent (VapA), intermediately virulent (VapB) and avirulent. Plasmid DNAs were isolated and analyzed by digestion with restriction endonucleases to estimate size and compare their polymorphisms. Of the 19 domestic pigs strains, seven (36.8%) were avirulent and 12 (63.2%) were intermediately virulent, with the intermediately virulent isolates being plasmid types 8 (8 isolates), 10 (2 isolates), 1 (1 isolate) and 29 (1 isolate). The plasmid type of four strains isolated from wild boars was also intermediately virulent type 8. None of the domestic pigs and wild boar isolates showed the vapA gene. These findings demonstrate a high occurrence of plasmid type 8 in isolates from pigs and wild boars, and the similarity of plasmid types in the domestic pigs, wild boars and human isolates in Brazil. Copyright © 2010 Elsevier Ltd. All rights reserved.

Antimicrobial susceptibility of Histophilus somni isolated from clinically affected cattle in Australia.

PubMed

Goldspink, Lauren K; Mollinger, Joanne L; Barnes, Tamsin S; Groves, Mitchell; Mahony, Timothy J; Gibson, Justine S

2015-02-01

This study investigated antimicrobial resistance traits, clonal relationships and epidemiology of Histophilus somni isolated from clinically affected cattle in Queensland and New South Wales, Australia. Isolates (n = 53) were subjected to antimicrobial susceptibility testing against six antimicrobial agents (ceftiofur, enrofloxacin, florfenicol, tetracycline, tilmicosin and tulathromycin) using disc diffusion and minimum inhibitory concentration (MIC) assays. Clonal relationships were assessed using repetitive sequence PCR and descriptive epidemiological analysis was performed. The H. somni isolates appeared to be geographically clonal, with 27/53 (47%) isolates grouping in one cluster from one Australian state. On the basis of disc diffusion, 34/53 (64%) isolates were susceptible to all antimicrobial agents tested; there was intermediate susceptibility to tulathromycin in 12 isolates, tilmicosin in seven isolates and resistance to tilmicosin in one isolate. Using MIC, all but one isolate was susceptible to all antimicrobial agents tested; the non-susceptible isolate was resistant to tetracycline, but this MIC result could not be compared to disc diffusion, since there are no interpretative guidelines for disc diffusion for H. somni against tetracycline. In this study, there was little evidence of antimicrobial resistance in H. somni isolates from Australian cattle. Disc diffusion susceptibility testing results were comparable to MIC results for most antimicrobial agents tested; however, results for isolates with intermediate susceptibility or resistance to tilmicosin and tulathromycin on disc diffusion should be interpreted with caution in the absence of MIC results. Copyright © 2014 Elsevier Ltd. All rights reserved.

Antimicrobial Susceptibility and Clonality of Clinical Ureaplasma Isolates in the United States

PubMed Central

Fernández, Javier; Karau, Melissa J.; Cunningham, Scott A.; Greenwood-Quaintance, Kerryl E.

2016-01-01

Ureaplasma urealyticum and Ureaplasma parvum are pathogens involved in urogenital tract and intrauterine infections and also in systemic diseases in newborns and immunosuppressed patients. There is limited information on the antimicrobial susceptibility and clonality of these species. In this study, we report the susceptibility of 250 contemporary isolates of Ureaplasma (202 U. parvum and 48 U. urealyticum isolates) recovered at Mayo Clinic, Rochester, MN. MICs of doxycycline, azithromycin, ciprofloxacin, tetracycline, erythromycin, and levofloxacin were determined by broth microdilution, with MICS of the last three interpreted according to CLSI guidelines. Levofloxacin resistance was found in 6.4% and 5.2% of U. parvum and U. urealyticum isolates, respectively, while 27.2% and 68.8% of isolates, respectively, showed ciprofloxacin MICs of ≥4 μg/ml. The resistance mechanism of levofloxacin-resistant isolates was due to mutations in parC, with the Ser83Leu substitution being most frequent, followed by Glu87Lys. No macrolide resistance was found among the 250 isolates studied; a single U. parvum isolate was tetracycline resistant. tet(M) was found in 10 U. parvum isolates, including the single tetracycline-resistant isolate, as well as in 9 isolates which had low tetracycline and doxycycline MICs. Multilocus sequence typing (MLST) performed on a selection of 46 isolates showed high diversity within the clinical Ureaplasma isolates studied, regardless of antimicrobial susceptibility. The present work extends previous knowledge regarding susceptibility to antimicrobial agents, resistance mechanisms, and clonality of Ureaplasma species in the United States. PMID:27246773

Pilot Study of Antimicrobial Resistance in Northern Bobwhites (Colinus virginianus).

PubMed

Zhang, Michael; Shen, Zhenyu; Rollins, Dale; Fales, William; Zhang, Shuping

2017-09-01

Antimicrobial resistance (AMR) is an important issue for both wildlife conservation and public health. The purpose of this study was to screen for AMR in fecal bacteria isolated from northern bobwhite (Colinus virginianus), a species that is an ecologically and economically important natural resource in the southern United States. The antimicrobial susceptibility profiles of 45 Escherichia coli isolates, 20 Enterococcus faecalis isolates, and 10 Enterococcus faecium isolates were determined using the Sensititer TM microbroth dilution minimum inhibitory concentration (MIC) plate, AVIAN1F. Overall, E. coli isolates had high MIC values for the following classes of antimicrobials: aminocoumarins, beta-lactams, lincosamides, macrolides, florfenicol, and sulfonamides. Enterococcus faecalis and E. faecium isolates had high MICs for aminocyclitols, aminoglycosides, beta-lactams, lincosamides, and sulfonamides. Enterococcus faecalis isolates also showed high MICs for aminocoumarins, while E. faecium isolates had high MICs for trimethoprim/sulfamethoxazole and tetracycline. Based on available veterinary interpretive criteria, 15% and 33% of E. coli isolates were resistant to sulphathiazole and sulphadimethoxine, respectively. Intermediate susceptibility to florfenicol was seen with 17.8% of E. coli isolates. Twenty percent of E. faecalis and 80% of E. faecium isolates were resistant to high-concentration streptomycin. One third of E. faecalis and 70% of E. faecium isolates were intermediately susceptible to erythromycin. Ten percent of E. faecium isolates were resistant to tetracycline and oxytetracycline. A comparison of available MIC suggests that AMR in wild bobwhite is less severe than in domestic poultry. Further investigation is needed to determine the source of AMR in wild bobwhite.

Analysis of isolates within species of anuran trypanosomes using random amplified polymorphic DNA.

PubMed

Lun, Z R; Desser, S S

1996-01-01

A total of 20 decamer primers were used to generate random applied polymorphic DNA (RAPD) markers from 5 isolates of Trypanosoma fallisi, 3 isolates of T. ranarum, 2 isolates of T. rotatorium, and 2 isolates of T. rotatorium-like trypanosomes in addition to 2 species from the American Type Culture Collection, T. chattoni (ATCC 50294) and Trypanosoma sp. (ATCC 50295). A slight polymorphism was observed among the four isolates of T. fallisi obtained form American toads, Bufo americanus, collected in Algonquin Park, Ontario, Canada, and an isolate obtained from the same species of host collected in Marquette, Michigan, United States, and produced similarity coefficients ranging from 80.7% to 96.9%. Pronounced polymorphism was recorded among the three isolates of T. ranarum from bullfrogs, Rana catesbeiana, collected in Ontario, Canada, and in Maryland, United States, and from a Northern leopard frog, R. pipiens, collected in Minnesota (USA). The similarity coefficients ranged from 54.7% to 59.5%, suggesting that alleles of these isolates were conserved over a wide geographic range. The high degree of polymorphism observed in two isolates of T. rotatorium from a bullfrog collected in Ontario and two isolates of a T. rotatorium-like parasite from the green frog R. clamitans, collected in Louisiana (USA) suggests that they are different species. These results reflect the high similarity among isolates from the same geographic location and the pronounced polymorphism apparent among isolates from distant geographic locations.

Development of vibration isolation platform for low amplitude vibration

NASA Astrophysics Data System (ADS)

Lee, Dae-Oen; Park, Geeyong; Han, Jae-Hung

2014-03-01

The performance of high precision payloads on board a satellite is extremely sensitive to vibration. Although vibration environment of a satellite on orbit is very gentle compared to the launch environment, even a low amplitude vibration disturbances generated by reaction wheel assembly, cryocoolers, etc may cause serious problems in performing tasks such as capturing high resolution images. The most commonly taken approach to protect sensitive payloads from performance degrading vibration is application of vibration isolator. In this paper, development of vibration isolation platform for low amplitude vibration is discussed. Firstly, single axis vibration isolator is developed by adapting three parameter model using bellows and viscous fluid. The isolation performance of the developed single axis isolator is evaluated by measuring force transmissibility. The measured transmissibility shows that both the low Q-factor (about 2) and the high roll-off rate (about -40 dB/dec) are achieved with the developed isolator. Then, six single axis isolators are combined to form Stewart platform in cubic configuration to provide multi-axis vibration isolation. The isolation performance of the developed multi-axis isolator is evaluated using a simple prototype reaction wheel model in which wheel imbalance is the major source of vibration. The transmitted force without vibration isolator is measured and compared with the transmitted force with vibration isolator. More than 20 dB reduction of the X and Y direction (radial direction of flywheel) disturbance is observed for rotating wheel speed of 100 Hz and higher.

Emergence of Resistance among USA300 Methicillin-Resistant Staphylococcus aureus Isolates Causing Invasive Disease in the United States▿

PubMed Central

McDougal, Linda K.; Fosheim, Gregory E.; Nicholson, Ainsley; Bulens, Sandra N.; Limbago, Brandi M.; Shearer, Julia E. S.; Summers, Anne O.; Patel, Jean B.

2010-01-01

USA300 methicillin-resistant Staphylococcus aureus (MRSA) isolates are usually resistant only to oxacillin, erythromycin, and, increasingly, levofloxacin. Of these, oxacillin and levofloxacin resistances are chromosomally encoded. Plasmid-mediated clindamycin, mupirocin, and/or tetracycline resistance has been observed among USA300 isolates, but these descriptions were limited to specific patient populations or isolated occurrences. We examined the antimicrobial susceptibilities of invasive MRSA isolates from a national surveillance population in order to identify USA300 isolates with unusual, possibly emerging, plasmid-mediated antimicrobial resistance. DNA from these isolates was assayed for the presence of resistance determinants and the presence of a pSK41-like conjugative plasmid. Of 823 USA300 isolates, 72 (9%) were tetracycline resistant; 69 of these were doxycycline susceptible and tetK positive, and 3 were doxycycline resistant and tetM positive. Fifty-one (6.2%) isolates were clindamycin resistant and ermC positive; 22 (2.7%) isolates were high-level mupirocin resistant (mupA positive); 5 (0.6%) isolates were trimethoprim-sulfamethoxazole (TMP-SMZ) resistant, of which 4 were dfrA positive; and 7 (0.9%) isolates were gentamicin resistant and aac6′-aph2″ positive. Isolates with pSK41-like plasmids (n = 24) were positive for mupA (n = 19), dfrA (n = 6), aac6′-aph2″ (n = 6), tetM (n = 2), and ermC (n = 8); 20 pSK41-positive isolates were positive for two or more resistance genes. Conjugative transfer of resistance was demonstrated between four gentamicin- and mupirocin-resistant and three gentamicin- and TMP-SMZ-resistant USA300 isolates; transconjugants harbored a single pSK41-like plasmid, which was PCR positive for aac6′-aph2″ and either mupA and/or dfrA. USA300 and USA100 isolates from the same state with identical resistance profiles contained pSK41-like plasmids with indistinguishable restriction and Southern blot profiles, suggesting horizontal plasmid transfer between USA100 and USA300 isolates. PMID:20585117

[Predictors of social isolation among older people living in urban area: a prospective study].

PubMed

Ejiri, Manami; Kawai, Hisashi; Fujiwara, Yoshinori; Ihara, Kazushige; Hirano, Hirohiko; Kojima, Motonaga; Obuchi, Shuichi

2018-01-01

Objectives　We aimed to investigate the predictors of social isolation among older people living in urban area.Methods　A mail survey was sent out to 7,015 elderly subjects living in nine districts of Itabashi ward. At baseline (2012), 3,696 subjects and at follow-up (2014) 2,375 replied to the self-administered questionnaire. We defined social isolation as seeing friends or relatives less than two or three times a month. Gender, age, self-rated health, present illnesses, instrumental activities of daily living (IADL), frequency of going out, frequency of social participation, family structure, and perceived financial status were also investigated. A t-test, a chi-square test, and logistic regression analysis were conducted to examine the predictors of social isolation in a follow-up study.Results　Of the 1,791 subjects who were analyzed for social isolation, 348 (19.4%) were found to be socially isolated in 2014. A multiple logistic regression analysis showed that men (adjusted odds ratio, 1.88; 95% confidence interval, 1.41-2.50) were significantly more likely to be isolated than women. Being older (1.03, 1.01-1.06) was also a significant predictor of isolation. Subjects who participated in group activities one to three times a month (1.62, 1.04-2.53) were significantly more likely to be isolated than those who participated in them more than once a week. Subjects who rated their financial status as low (1.67, 1.20-2.32) were more likely to be isolated than those who rated it as high. Subjects who were isolated (10.24, 7.60-13.81), and those who did not respond to questions about isolation (8.15, 3.76-17.67), were significantly more likely to be isolated than those who were not isolated at baseline. Among the subjects who were not isolated at baseline, being male (2.39, 1.57-3.64) and lower self-rated health (3.99, 1.33-11.94) were predictors of social isolation.Conclusion　Participation in social activities is effective in preventing social isolation among elderly men living in urban area.

Inhibitor-resistant TEM- and OXA-1-producing Escherichia coli isolates resistant to amoxicillin-clavulanate are more clonal and possess lower virulence gene content than susceptible clinical isolates.

PubMed

Oteo, Jesús; González-López, Juan José; Ortega, Adriana; Quintero-Zárate, J Natalia; Bou, Germán; Cercenado, Emilia; Conejo, María Carmen; Martínez-Martínez, Luis; Navarro, Ferran; Oliver, Antonio; Bartolomé, Rosa M; Campos, José

2014-07-01

In a previous prospective multicenter study in Spain, we found that OXA-1 and inhibitor-resistant TEM (IRT) β-lactamases constitute the most common plasmid-borne mechanisms of genuine amoxicillin-clavulanate (AMC) resistance in Escherichia coli. In the present study, we investigated the population structure and virulence traits of clinical AMC-resistant E. coli strains expressing OXA-1 or IRT and compared these traits to those in a control group of clinical AMC-susceptible E. coli isolates. All OXA-1-producing (n = 67) and IRT-producing (n = 45) isolates were matched by geographical and temporal origin to the AMC-susceptible control set (n = 56). We performed multilocus sequence typing and phylogenetic group characterization for each isolate and then studied the isolates for the presence of 49 virulence factors (VFs) by PCR and sequencing. The most prevalent clone detected was distinct for each group: group C isolates of sequence type (ST) 88 (C/ST88) were the most common in OXA-1 producers, B2/ST131 isolates were the most common in IRT producers, and B2/ST73 isolates were the most common in AMC-susceptible isolates. The median numbers of isolates per ST were 3.72 in OXA-1 producers, 2.04 in IRT producers, and 1.69 in AMC-susceptible isolates; the proportions of STs represented by one unique isolate in each group were 19.4%, 31.1%, and 48.2%, respectively. The sum of all VFs detected, calculated as a virulence score, was significantly higher in AMC-susceptible isolates than OXA-1 and IRT producers (means, 12.5 versus 8.3 and 8.2, respectively). Our findings suggest that IRT- and OXA-1-producing E. coli isolates resistant to AMC have a different and less diverse population structure than AMC-susceptible clinical E. coli isolates. The AMC-susceptible population also contains more VFs than AMC-resistant isolates. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Differentiation of BHV-1 isolates from vaccine virus by high-resolution melting analysis.

PubMed

Ostertag-Hill, Claire; Fang, Liang; Izume, Satoko; Lee, Megan; Reed, Aimee; Jin, Ling

2015-02-16

An efficacious bovine herpesvirus type-1 (BHV-1) vaccine has been used for many years. However, in the past few years, abortion and respiratory diseases have occurred after administration of the modified live vaccine. To investigate whether BHV-1 isolates from disease outbreaks are identical to those of the vaccines used, selected regions of the BHV-1 genome were investigated by high-resolution melting (HRM) analysis and PCR-DNA sequencing. When a target region within the thymidine kinase (TK) gene was examined by HRM analysis, 6 out of the 11 isolates from abortion cases and 22 out of the 25 isolates from bovine respiratory disease (BRD) cases had different melting curves compared to the vaccine virus. Surprisingly, when a conserved region within the US6 gene that encodes glycoprotein D (gD) was examined by HRM analysis, 5 out of the 11 abortion isolates and 18 out of the 23 BRD isolates had different melting curves from the vaccine virus. To determine whether SNPs within the coding regions of glycoprotein E (gE) and TK genes can be used to differentiate the isolates from the vaccine virus, PCR-DNA sequencing was used to examine these SNPs in all the isolates. This revealed that only 1 out of 11 of the abortion isolates and 4 out of 24 of the BRD isolates are different in the target region of gE from the vaccine virus, while 5 out of 11 abortion isolates and 4 out of 22 BRD isolates are different in the target region of TK from the vaccine virus. No DNA sequence differences were observed in glycoprotein G (gG) region between disease and vaccine isolates. Our study demonstrated that many disease isolates had genetic differences from the vaccine virus in regions examined by HRM and PCR-DNA sequencing analysis. In addition, many isolates contained more than one type of mutation and were composed of mixed variants. Our study suggests that a mixture of variants were present in isolates collected post-vaccination. HRM is a rapid diagnostic method that can be used for rapid differentiation of clinical isolates from vaccine strains. Copyright © 2014 Elsevier B.V. All rights reserved.

Optical depth retrievals from Delta-T SPN1 measurements of broadband solar irradiance at ground

NASA Astrophysics Data System (ADS)

Estelles, Victor; Serrano, David; Segura, Sara; Wood, John; Webb, Nick

2016-04-01

The SPN1 radiometer, manufactured by Delta-T Devices Ltd., is an instrument designed for the measurement of global solar irradiance and its components (diffuse, direct) at ground level. In the present study, the direct irradiance component has been used to retrieve an effective total optical depth, by applying the Beer-Lambert law to the broadband measurements. The results have been compared with spectral total optical depths derived from two Cimel CE318 and Prede POM01 sun-sky radiometers, located at the Burjassot site in Valencia (Spain), during years 2013 - 2015. The SPN1 is an inexpensive and versatile instrument for the measurement of the three components of the solar radiation without any mobile part and without any need to azimuthally align the instrument to track the sun (http://www.delta-t.co.uk). The three components of the solar radiation are estimated from a combination of measurements performed by 7 different miniature thermopiles. In turn, the Beer-Lambert law has been applied to the broadband direct solar component to obtain an effective total optical depth, representative of the total extinction in the atmosphere. For the assessment of the total optical depth values retrieved with the SPN1, two different sun-sky radiometers (Cimel CE318 and Prede POM01L) have been employed. Both instruments belong to the international networks AERONET and SKYNET. The modified SUNRAD package has been applied in both Cimel and Prede instruments. Cloud affected data has been removed by applying the Smirnov cloud-screening procedure in the SUNRAD algorithm. The broadband SPN1 total optical depth has been analysed by comparison with the spectral total optical depth from the sun-sky radiometer measurements at wavelengths 440, 500, 675, 870 and 1020 nm. The slopes and intercepts have been estimated to be 0.47 - 0.98 and 0.055 - 0.16 with increasing wavelength. The average correlation coefficients and RMSD were 0.80 - 0.83 and 0.034 - 0.036 for all the channels. The analysis shows that the SPN1 instrument underestimates the TOD increasingly with wavelength, for higher TOD. This observation is in agreement with the already known effect of a larger effective field of view in the SPN1, as the aureole radiation increase. In any case, these results are promising and would be useful as a determination of the total atmospheric extinction, mainly for users of the SPN1 in the solar radiation field.

Phylogenetic Diversity of Vibrio cholerae Associated with Endemic Cholera in Mexico from 1991 to 2008.

PubMed

Choi, Seon Young; Rashed, Shah M; Hasan, Nur A; Alam, Munirul; Islam, Tarequl; Sadique, Abdus; Johura, Fatema-Tuz; Eppinger, Mark; Ravel, Jacques; Huq, Anwar; Cravioto, Alejandro; Colwell, Rita R

2016-03-15

An outbreak of cholera occurred in 1991 in Mexico, where it had not been reported for more than a century and is now endemic. Vibrio cholerae O1 prototype El Tor and classical strains coexist with altered El Tor strains (1991 to 1997). Nontoxigenic (CTX(-)) V. cholerae El Tor dominated toxigenic (CTX(+)) strains (2001 to 2003), but V. cholerae CTX(+) variant El Tor was isolated during 2004 to 2008, outcompeting CTX(-) V. cholerae. Genomes of six Mexican V. cholerae O1 strains isolated during 1991 to 2008 were sequenced and compared with both contemporary and archived strains of V. cholerae. Three were CTX(+) El Tor, two were CTX(-) El Tor, and the remaining strain was a CTX(+) classical isolate. Whole-genome sequence analysis showed the six isolates belonged to five distinct phylogenetic clades. One CTX(-) isolate is ancestral to the 6th and 7th pandemic CTX(+) V. cholerae isolates. The other CTX(-) isolate joined with CTX(-) non-O1/O139 isolates from Haiti and seroconverted O1 isolates from Brazil and Amazonia. One CTX(+) isolate was phylogenetically placed with the sixth pandemic classical clade and the V. cholerae O395 classical reference strain. Two CTX(+) El Tor isolates possessing intact Vibrio seventh pandemic island II (VSP-II) are related to hybrid El Tor isolates from Mozambique and Bangladesh. The third CTX(+) El Tor isolate contained West African-South American (WASA) recombination in VSP-II and showed relatedness to isolates from Peru and Brazil. Except for one isolate, all Mexican isolates lack SXT/R391 integrative conjugative elements (ICEs) and sensitivity to selected antibiotics, with one isolate resistant to streptomycin. No isolates were related to contemporary isolates from Asia, Africa, or Haiti, indicating phylogenetic diversity. Sequencing of genomes of V. cholerae is critical if genetic changes occurring over time in the circulating population of an area of endemicity are to be understood. Although cholera outbreaks occurred rarely in Mexico prior to the 1990s, genetically diverse V. cholerae O1 strains were isolated between 1991 and 2008. Despite the lack of strong evidence, the notion that cholera was transmitted from Africa to Latin America has been proposed in the literature. In this study, we have applied whole-genome sequence analysis to a set of 124 V. cholerae strains, including six Mexican isolates, to determine their phylogenetic relationships. Phylogenetic analysis indicated the six V. cholerae O1 isolates belong to five phylogenetic clades: i.e., basal, nontoxigenic, classical, El Tor, and hybrid El Tor. Thus, the results of phylogenetic analysis, coupled with CTXϕ array and antibiotic susceptibility, do not support single-source transmission of cholera to Mexico from African countries. The association of indigenous populations of V. cholerae that has been observed in this study suggests it plays a significant role in the dynamics of cholera in Mexico. Copyright © 2016 Choi et al.

[Susceptibilities of Escherichia coli, Salmonella and Staphylococcus aureus isolated from animals to ofloxacin and commonly used antimicrobial agents].

PubMed

Takahashi, I; Yoshida, T; Higashide, Y; Sakano, T

1990-01-01

Susceptibilities of Escherichia coli, Salmonella and Staphylococcus aureus isolated from chickens, pigs and cattle to ofloxacin (OFLX) and commonly used antimicrobial agents were investigated. 1. E. coli (28 isolates) demonstrated the highest level of susceptibility of OFLX (MIC 0.10-0.39 micrograms/ml for all the isolates) among all the test drugs. Commonly used antimicrobial agents to which these isolates responded with relatively high susceptibilities (MIC50 0.78-6.25 micrograms/ml) included oxolinic acid (OXA), ampicillin (ABPC), kanamycin (KM) and chloramphenicol (CP) with their MIC50 values in the increasing order as above. Drugs to which these isolates responded with moderate to weak susceptibilities (MIC50 25 approximately greater than 800 micrograms/ml) were doxycycline (DOXY), streptomycin (SM), spectinomycin (SPCM) and sulfadimethoxine (SDMX) in the increasing order of MIC50. E. coli isolates with resistances to all the test drugs other than OFLX and OXA amounted to 7.1-57.1% of the isolates examined and 20 isolates (71.4%) in total. 2. Susceptibilities to OFLX and 4 existing pyridonecarboxylic acid derivatives of E. coli (48 samples) isolated recently from diarrheal pigs were compared. When evaluated in terms of MIC50, the values of OFLX and norfloxacin were both 0.10 micrograms/ml. The values increased by differences of 0.39-3.13 micrograms/ml in an order of OXA, pipemidic acid and nalidixic acid. 3. Salmonella (28 isolates) demonstrated the highest level of susceptibility to OFLX (MIC 0.20-0.39 micrograms/ml for all the isolates) among all the test drugs. The drugs to which these isolates responded with relatively high to moderate susceptibilities (MIC50 0.78-12.5 micrograms/ml) included ABPC, OXA, DOXY, KM, CP and SM with their MIC50 values increasing in this order. The drugs to which the isolates responded with low susceptibilities (MIC50 above 100 micrograms/ml) were SPCM and SDMX. Of all the 28 Salmonella isolates tested, 7.1-32.1% were resistant to all the test drugs other than OFLX and OXA. These resistant isolates amounted to a total of 12 isolates (42.9%). 4. S. aureus (28 isolates) were highly susceptible to OFLX (MIC50 and MIC90 were both 0.78 micrograms/ml). Commonly used antimicrobial agents to which the isolates responded with high to relatively high susceptibilities (MIC50 0.10-6.25 micrograms/ml) were, in the increasing order of MIC50: DOXY, ABPC, tylosin, tiamulin, KM, OXA and CP. Drugs with moderate to low bacterial susceptibilities (MIC50 12.5-100 microns/ml) were SD, SDMX and SPCM. Isolates resistant to all the test drugs except OFLX and SDMX amounted to 3.6-50% of the 28 isolates examined and they totalled 20 isolates (71.4%).(ABSTRACT TRUNCATED AT 400 WORDS)

Prevalence of multiple drug resistant Streptococcus suis in and around Guwahati, India.

PubMed

Devi, Mrinalee; Dutta, Jyoti B; Rajkhowa, Swaraj; Kalita, Dhireswar; Saikia, Girindra Kumar; Das, Bipin Chandra; Hazarika, Razibuddin Ahmed; Mahato, Gauranga

2017-05-01

This study was conducted to determine the prevalence and antimicrobial susceptibility of Streptococcus suis and their resistance patterns isolated from both clinically healthy carriers and diseased pigs in and around Guwahati, Assam, India. A total of 497 samples were collected during October, 2012, to April, 2014, from clinically healthy (n=67) and diseased (n=230) pigs of varying age and either sex maintained under organized and unorganized farming systems. Samples were processed for isolation and identification of S. suis by biochemical characterization and polymerase chain reaction targeting the housekeeping gene glutamate dehydrogenase. In vitro antimicrobial susceptibility of the recovered isolates against nine antibiotic groups comprising 17 antimicrobial agents was studied by standard method. Of the 497 samples examined, 7 (1.41%) isolates were confirmed to be S. suis of which 5 (1.87%) and 2 (0.87%) were derived from clinically healthy and diseased pigs, respectively. All the isolates were susceptible to gentamicin, amikacin, and erythromycin (100%) followed by the penicillin group and enrofloxacin (85.71%), ceftriaxone, doxycycline HCL, ofloxacin and chloramphenicol (71.43%), to kanamycin, clindamycin and co-trimoxazole (42.85%). The isolates showed least susceptibility to cefalexin, tetracycline and streptomycin (28.57%). All the five S. suis isolates from clinically healthy pigs were susceptible to penicillin G, amoxyclav, doxycycline HCl, gentamicin, amikacin and erythromycin, 80.00% isolates susceptible to ampicillin, enrofloxacin and ofloxacin, 60.00% to ceftriaxone, kanamycin and chloramphenicol, 40% to cefalexin, tetracycline, clindamycin and co-trimoxazole, respectively. Only 20.00% isolates were susceptible to streptomycin. Both the isolates recovered from diseased pigs were susceptible to ampicillin, ceftriaxone, gentamicin, amikacin, enrofloxacin, erythromycin, and clindamycin. On the other hand, both the isolates were resistant to cefalexin, tetracycline, doxycycline HCL, and kanamycin. Altogether five different resistance patterns (multi-drug resistance) were observed. Of the seven S. suis isolates, two isolates were susceptible to all the 17 antimicrobial agents, one isolate was resistant to four antimicrobial agents, two isolates to seven agents, one isolate to nine agents, and one isolate exhibited resistance to 14 antimicrobial agents. This study was conducted to determine the prevalence of S. suis in clinically healthy and diseased pigs and their antimicrobial susceptibility patterns. All the isolates were susceptible to gentamicin, amikacin and erythromycin, and most of them were resistant to cefalexin, tetracycline and streptomycin. Five different patterns of antimicrobial resistance (multi-drug resistance) were observed.

In Vitro Activity of the Siderophore Cephalosporin, Cefiderocol, against a Recent Collection of Clinically Relevant Gram-Negative Bacilli from North America and Europe, Including Carbapenem-Nonsusceptible Isolates (SIDERO-WT-2014 Study).

PubMed

Hackel, Meredith A; Tsuji, Masakatsu; Yamano, Yoshinori; Echols, Roger; Karlowsky, James A; Sahm, Daniel F

2017-09-01

Cefiderocol (formerly S-649266) is an investigational siderophore cephalosporin. Iron-depleted cation-adjusted Mueller-Hinton broth (ID-CAMHB) was prepared according to the Clinical and Laboratory Standards Institute (CLSI) protocol and used to perform broth microdilution testing of cefiderocol against a 2014-2015 collection of clinical isolates of Gram-negative bacilli from North America ( n = 4,239) and Europe ( n = 4,966). The concentrations of cefiderocol inhibiting 90% of isolates tested (MIC 90 s) were 0.5 μg/ml (North America; n = 3,007) and 1 μg/ml (Europe; n = 3,080) for all isolates of Enterobacteriaceae ; 1 μg/ml (North America; n = 30) and 4 μg/ml (Europe; n = 139) for meropenem-nonsusceptible (MIC ≥ 2 μg/ml) isolates of Enterobacteriaceae ; 0.5 μg/ml for both North American ( n = 765) and European ( n = 765) isolates of Pseudomonas aeruginosa ; 0.5 μg/ml (North America; n = 151) and 1 μg/ml (Europe; n = 202) for meropenem-nonsusceptible (MIC ≥ 4 μg/ml) isolates of P. aeruginosa ; 1 μg/ml for both North American ( n = 309) and European ( n = 839) isolates of all Acinetobacter baumannii strains as well as for both North American ( n = 173) and European ( n = 595) isolates of meropenem-nonsusceptible A. baumannii ; and 0.5μg/ml (North America; n = 152) and 0.25 μg/ml (Europe; n = 276) for isolates of Stenotrophomonas maltophilia MICs of cefiderocol were ≤4 μg/ml for 99.9% (6,078/6,087) of all Enterobacteriaceae , 97.0% (164/169) of meropenem-nonsusceptible Enterobacteriaceae , 99.9% (1,529/1,530) of all P. aeruginosa isolates, 100% (353/353) of meropenem-nonsusceptible P. aeruginosa isolates, 97.6% (1,120/1,148) of all A. baumannii isolates, 96.9% (744/768) of meropenem-nonsusceptible A. baumannii isolates, 100% of isolates of S. maltophilia (428/428) and 93.8% of isolates of Burkholderia cepecia (11/12). We conclude that cefiderocol demonstrated potent in vitro activity against a recent collection of clinical isolates of commonly encountered Gram-negative bacilli, including carbapenem-nonsusceptible isolates. Copyright © 2017 American Society for Microbiology.

Identification of Isolates that Cause a Leaf Spot Disease of Brassicas as Xanthomonas campestris pv. raphani and Pathogenic and Genetic Comparison with Related Pathovars.

PubMed

Vicente, J G; Everett, B; Roberts, S J

2006-07-01

ABSTRACT Twenty-five Xanthomonas isolates, including some isolates received as either X. campestris pv. armoraciae or pv. raphani, caused discrete leaf spot symptoms when spray-inoculated onto at least one Brassica oleracea cultivar. Twelve of these isolates and four other Xanthomonas isolates were spray- and pin-inoculated onto 21 different plant species/cultivars including horseradish (Armoracia rusticana), radish (Raphanus sativus), and tomato (Lycopersicon esculentum). The remaining 13 leaf spot isolates were spray-inoculated onto a subset of 10 plant species/cultivars. The leaf spot isolates were very aggressive on several Brassica spp., radish, and tomato causing leaf spots and dark sunken lesions on the middle vein, petiole, and stem. Based on the differential reactions of several Brassica spp. and radish cultivars, the leaf spot isolates were divided into three races, with races 1 and 3 predominating. A differential series was established to determine the race-type of isolates and a gene-for-gene model based on the interaction of two avirulence genes in the pathogen races and two matching resistance genes in the differential hosts is proposed. Repetitive-DNA polymerase chain reaction-based fingerprinting was used to assess the genetic diversity of the leaf spot isolates and isolates of closely related Xanthomonas pathovars. Although there was variability within each race, the leaf spot isolates were clustered separately from the X. campestris pv. campestris isolates. We propose that X. campestris isolates that cause a nonvascular leaf spot disease on Brassica spp. should be identified as pv. raphani and not pv. armoraciae. Race-type strains and a neopathotype strain for X. campestris pv. raphani are proposed.

Distinct Transcriptional Profiles and Phenotypes Exhibited by Escherichia coli O157:H7 Isolates Related to the 2006 Spinach-Associated Outbreak

PubMed Central

Kyle, Jennifer L.; Huynh, Steven; Carter, Michelle Q.; Brandl, Maria T.; Mandrell, Robert E.

2012-01-01

In 2006, a large outbreak of Escherichia coli O157:H7 was linked to the consumption of ready-to-eat bagged baby spinach in the United States. The likely sources of preharvest spinach contamination were soil and water that became contaminated via cattle or feral pigs in the proximity of the spinach fields. In this study, we compared the transcriptional profiles of 12 E. coli O157:H7 isolates that possess the same two-enzyme pulsed-field gel electrophoresis (PFGE) profile and are related temporally or geographically to the above outbreak. These E. coli O157:H7 isolates included three clinical isolates, five isolates from separate bags of spinach, and single isolates from pasture soil, river water, cow feces, and a feral pig. The three clinical isolates and two spinach bag isolates grown in cultures to stationary phase showed decreased expression of many σS-regulated genes, including gadA, osmE, osmY, and katE, compared with the soil, water, cow, feral pig, and the other three spinach bag isolates. The decreased expression of these σS-regulated genes was correlated with the decreased resistance of the isolates to acid stress, osmotic stress, and oxidative stress but increases in scavenging ability. We also observed that intraisolate variability was much more pronounced among the clinical and spinach isolates than among the environmental isolates. Together, the transcriptional and phenotypic differences of the spinach outbreak isolates of E. coli O157:H7 support the hypothesis that some variants within the spinach bag retained characteristics of the preharvest isolates, whereas other variants with altered gene expression and phenotypes infected the human host. PMID:22081562

Patients' perceived level of social isolation affects the prognosis of low back pain.

PubMed

Oliveira, V C; Ferreira, M L; Morso, L; Albert, H B; Refshauge, K M; Ferreira, P H

2015-04-01

Perceived social isolation is prevalent among patients with low back pain (LBP) and could be a potential prognostic factor for clinical outcomes following an episode of LBP. A secondary analysis of an original prospective cohort study, which investigated the validity of the Danish version of the STarT Back Screening Tool (STarT), investigated whether social isolation predicts the clinical outcomes of disability, anxiety, depression and pain catastrophizing in people with LBP. Patients with LBP of any duration (N = 204) from Middelfart, Denmark, were included. Social isolation was measured at baseline using the friendship scale (score ranges from 0 to 24, with lower values meaning higher perceived social isolation), and outcomes were measured at baseline and at 6-month follow-up. Regression models investigated whether social isolation at baseline predicted the outcomes at 6-month follow-up. Some level of social isolation was reported by 39.2% of the participants (n = 80) with 5.9% (n = 12) being very socially isolated. One-point difference on social isolation predicted one point on a 100-point disability scale (adjusted unstandardized coefficient: -0.91; 95% confidence interval (CI): -1.56 to -0.26). Social isolation predicted anxiety; however, a change of one point on the social isolation scale represents a difference of only 0.08 points on a 22-point scale in anxiety (95% CI: 0.01-0.15) and is unlikely to denote clinical importance. Social isolation did not predict pain catastrophizing or depression. Patients' perceived social isolation predicts disability related to LBP. Further understanding of the role of social isolation in LBP is warranted. © 2014 European Pain Federation - EFIC®

Whole genome typing of the recently emerged Canadian serogroup W Neisseria meningitidis sequence type 11 clonal complex isolates associated with invasive meningococcal disease.

PubMed

Tsang, Raymond S W; Ahmad, Tauqeer; Tyler, Shaun; Lefebvre, Brigitte; Deeks, Shelley L; Gilca, Rodica; Hoang, Linda; Tyrrell, Gregory; Van Caeseele, Paul; Van Domselaar, Gary; Jamieson, Frances B

2018-04-01

This study was performed to analyze the Canadian invasive serogroup W Neisseria meningitidis (MenW) sequence type 11 (ST-11) clonal complex (CC) isolates by whole genome typing and to compare Canadian isolates with similar isolates from elsewhere. Whole genome typing of 30 MenW ST-11 CC, 20 meningococcal group C (MenC) ST-11 CC, and 31 MenW ST-22 CC isolates was performed on the Bacterial Isolate Genome Sequence database platform. Canadian MenW ST-11 CC isolates were compared with the 2000 MenW Hajj outbreak strain, as well as with MenW ST-11 CC from other countries. Whole genome typing showed that the Canadian MenW ST-11 CC isolates were distinct from the traditional MenW ST-22 CC; they were not capsule-switched contemporary MenC strains that incorporated MenW capsules. While some recent MenW disease cases in Canada were caused by MenW ST-11 CC isolates showing relatedness to the 2000 MenW Hajj strain, many were non-Hajj isolates similar to current MenW ST-11 isolates found globally. Geographical and temporal variations in genotypes and surface protein antigen genes were found among the MenW ST-11 CC isolates. The current MenW ST-11 isolates did not arise by capsule switching from contemporary MenC ST-11 isolates. Both the Hajj-related and non-Hajj MenW ST-11 CC strains were associated with invasive meningococcal disease in Canada. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Characterization of Staphylococcus aureus isolates from retail chicken carcasses and pet workers in Northwest Arkansas.

PubMed

Hanning, Irene; Gilmore, David; Pendleton, Sean; Fleck, Scott; Clement, Ashley; Park, Si Hong; Scott, Erin; Ricke, Steven C

2012-01-01

Staphylococcus aureus can be carried on the skin and nasal passages of humans and animals as a commensal. A case of human methicillin-resistant S. aureus infection resulting from contact with pork has been reported. Poultry carcasses are sold at retail with the skin intact, but pork and beef typically are not. Thus, the risk of methicillin-resistant S. aureus human infection from whole raw poultry carcasses may be greater than that of exposure from pork or beef. The objective of this study was to isolate and characterize S. aureus from whole retail poultry carcasses and compare the isolates to S. aureus isolates from humans. A total of 25 S. aureus isolates were collected from 222 whole poultry carcasses. The isolates were characterized phenotypically with antibiotic resistance disc diffusion assays and genotypically using multilocus sequence typing. A total of 17 S. aureus isolates obtained from healthy humans were included and characterized in the same way as the poultry isolates. Staphylococcus spp. were recovered from all poultry carcasses. Only 25 poultry carcasses (11.2%) were contaminated with S. aureus. Of these 25 isolates, 36% were resistant to at least one of the antibiotics tested and 20% were resistant to two or more antibiotics tested. However, 100% of the human isolates were resistant to at least one of the antibiotics and 94% were resistant to two or more antibiotics. The results of the multilocus sequence typing indicate that most of the isolates grouped according to source. These results indicate a low prevalence of S. aureus present in poultry, and the isolates were not phenotypically similar to human isolates. The low number of S. aureus isolates from this study indicates that chicken carcasses would appear to not be a significant source of this bacterium.

Comparison of broad-spectrum cephalosporin-resistant Escherichia coli isolated from dogs and humans in Hokkaido, Japan.

PubMed

Okubo, Torahiko; Sato, Toyotaka; Yokota, Shin-ichi; Usui, Masaru; Tamura, Yutaka

2014-04-01

Resistance to broad-spectrum cephalosporins (BSCs) in Enterobacteriaceae in companion animals has become a great concern for public health. To estimate the dissemination of BSC-resistant bacteria between dog and human, we examined the BSC-resistance determinants of and genetic similarities between 69 BSC-resistant Escherichia coli isolates derived from canine rectal swabs (n = 28) and human clinical samples (n = 41). Some E. coli isolates possessed blaTEM-1b (14 canine and 16 human isolates), blaCTx-M-2 (6 human isolates), blaCTx-M-14 (3 canine and 14 human isolates), blaCTx-M-27 (1 canine and 15 human isolates), and blaCMY-2 (11 canine and 3 human isolates). The possession of CTX-M-type β-lactamases was significantly more frequent in human isolates, whereas CMY-2 was more common in canine isolates. Bacterial typing methods (phylogenetic typing, O-antigen serotyping, and pulsed-field gel electrophoresis) showed little clonal relationship between canine isolates and human isolates. Plasmid analysis and Southern blotting indicated that the plasmids encoding CMY-2 were similar among canine and human isolates. Based on the differences in the major β-lactamase and the divergence of bacterial types between canine and human isolates, it seems that clonal dissemination of BSC-resistant E. coli between canines and humans is limited. The similarity of the CMY-2-encoding plasmid suggests that plasmid-mediated β-lactamase gene transmission plays a role in interspecies diffusion of BSC-resistant E. coli between dog and human. Copyright © 2013 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Surveillance for azole resistance in clinical and environmental isolates of Aspergillus fumigatus in Australia and cyp51A homology modelling of azole-resistant isolates.

PubMed

Talbot, Jessica J; Subedi, Shradha; Halliday, Catriona L; Hibbs, David E; Lai, Felcia; Lopez-Ruiz, Francisco J; Harper, Lincoln; Park, Robert F; Cuddy, William S; Biswas, Chayanika; Cooley, Louise; Carter, Dee; Sorrell, Tania C; Barrs, Vanessa R; Chen, Sharon C-A

2018-05-29

The prevalence of azole resistance in Aspergillus fumigatus is uncertain in Australia. Azole exposure may select for resistance. We investigated the frequency of azole resistance in a large number of clinical and environmental isolates. A. fumigatus isolates [148 human, 21 animal and 185 environmental strains from air (n = 6) and azole-exposed (n = 64) or azole-naive (n = 115) environments] were screened for azole resistance using the VIPcheck™ system. MICs were determined using the Sensititre™ YeastOne YO10 assay. Sequencing of the Aspergillus cyp51A gene and promoter region was performed for azole-resistant isolates, and cyp51A homology protein modelling undertaken. Non-WT MICs/MICs at the epidemiological cut-off value of one or more azoles were observed for 3/148 (2%) human isolates but not amongst animal, or environmental, isolates. All three isolates grew on at least one azole-supplemented well based on VIPcheck™ screening. For isolates 9 and 32, the itraconazole and posaconazole MICs were 1 mg/L (voriconazole MICs 0.12 mg/L); isolate 129 had itraconazole, posaconazole and voriconazole MICs of >16, 1 and 8 mg/L, respectively. Soil isolates from azole-exposed and azole-naive environments had similar geometric mean MICs of itraconazole, posaconazole and voriconazole (P > 0.05). A G54R mutation was identified in the isolates exhibiting itraconazole and posaconazole resistance, and the TR34/L98H mutation in the pan-azole-resistant isolate. cyp51A modelling predicted that the G54R mutation would prevent binding of itraconazole and posaconazole to the haem complex. Azole resistance is uncommon in Australian clinical and environmental A. fumigatus isolates; further surveillance is indicated.

Molecular epidemiology of invasive Candida albicans at a tertiary hospital in northern Taiwan from 2003 to 2011.

PubMed

Wang, Shao-Hung; Shen, Mandy; Lin, Hsin-Chieh; Sun, Pei-Lun; Lo, Hsiu-Jung; Lu, Jang-Jih

2015-11-01

Candida albicans is a common cause of bloodstream fungal infections in hospitalized patients. To investigate its epidemiology, multilocus sequence typing (MLST) was performed on 285 C. albicans bloodstream isolates from patients in Chang Gung Memorial Hospital at Linkou (CGMHL), Taiwan from 2003 to 2011. Among these isolates, the three major diploid sequence types (DSTs) were 693, 659, and 443 with 19, 16, and 13 isolates, respectively. The 179 DSTs were classified into 16 clades by unweighted pair-group method using arithmetic averages (UPGMA). The major ones were clades 1, 4, 3, and 17 (54, 49, 31, and 31 isolates, respectively). Further analyses with eBURST clustered the 285 isolates into 28 clonal complexes (CC). The most common complexes were CC8, CC20, and CC9. DST 693 that had the highest number of isolates was determined to be the cluster founder of CC20, which belonged to clade 3. So far, 33 isolates worldwide including 29 from Taiwan and 4 from Korea, are CC20, suggesting that CC20 is an Asian cluster. Two fluconazole-resistant isolates belonging to CC12 and CC19 were detected. All other CGMHL isolates were susceptible to 5-flucytosine, amphotericin B, anidulfungin, caspofungin, fluconazole, itraconazole, micafungin, posaconazole, and voriconazole. However, CC20 isolates exhibited significantly lower susceptibility to fluconazole. In conclusion, the 285 CGMHL C. albicans isolates displayed geographically clustering with Asian isolates, and most of them are susceptible to common antifungal drugs. Isolates of DST 693, a Taiwanese major genotype belonging to MLST clade 3, were more resistant to fluconazole than other isolates. © The Author 2015. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Characterization of Mycobacterium bohemicum Isolated from Human, Veterinary, and Environmental Sources

PubMed Central

Torkko, Pirjo; Suomalainen, Sini; Iivanainen, Eila; Suutari, Merja; Paulin, Lars; Rudbäck, Eeva; Tortoli, Enrico; Vincent, Véronique; Mattila, Rauni; Katila, Marja-Leena

2001-01-01

Chemotaxonomic and genetic properties were determined for 14 mycobacterial isolates identified as members of a newly described species Mycobacterium bohemicum. The isolates recovered from clinical, veterinary, and environmental sources were compared for lipid composition, biochemical test results, and sequencing of the 16S ribosomal DNA (rDNA) and the 16S-23S rDNA internal transcribed spacer (ITS) regions. The isolates had a lipid composition that was different from those of other known species. Though the isolates formed a distinct entity, some variations were detected in the features analyzed. Combined results of the phenotypic and genotypic analyses were used to group the isolates into three clusters. The major cluster (cluster A), very homogenous in all respects, comprised the M. bohemicum type strain, nine clinical and veterinary isolates, and two of the five environmental isolates. Three other environmental isolates displayed an insertion of 14 nucleotides in the ITS region; they also differed from cluster A in fatty alcohol composition and produced a positive result in the Tween 80 hydrolysis test. Among these three, two isolates were identical (cluster B), but one isolate (cluster C) had a unique high-performance liquid chromatography profile, and its gas liquid chromatography profile lacked 2-octadecanol, which was present in all other isolates analyzed. Thus, sequence variation in the 16S-23S ITS region was associated with interesting variations in lipid composition. Two of the isolates analyzed were regarded as potential inducers of human or veterinary infections. Each of the environmental isolates, all of which were unrelated to the cases presented, was cultured from the water of a different stream. Hence, natural waters are potential reservoirs of M. bohemicum. PMID:11136772

Temperature range and degree of acidity growth of isolate of indigenous bacteria on fermented feed “fermege”

NASA Astrophysics Data System (ADS)

Isnawati; Trimulyono, G.

2018-01-01

Fermege is a fermented feed of ruminants, especially goats made from water hyacinth (Eichhornia crassipes). Temperature range and pH need to know in making starter formula for acceleration of fermentation process at making ruminant feed made from this materials. The starter formula expired period can be extended by adjusting starter storage temperature and pH of the starter. This research was aimed to find the temperature and pH range for the growth of isolate of indigenous bacteria “fermege.” This research is an explorative research conducted by growing bacteria isolate indigenous fermege in liquid medium with various pH and incubation in various temperature. Bacterial population was calculated based on turbidity of bacterial suspension with turbidometer. The stages of this research were to isolate the bacteria present in the fermege, purify the isolates found, and then grow the isolates in a liquid medium with various pH values. The isolated bacterials were incubated at different temperature variations. The cell population density of the isolates was calculated after incubation for 24 hours. The results showed there were eight indigenous bacterial isolates. All isolates can grow in the pH range 6 and 7. Two isolates (Bacillus subtilis and B. pumilus) can grow at 4°C. All isolates obtained can grow at a temperature of 30°C. Isolates Bacillus badius, B. subtilis, B. cereus, Pseudomonas stutzeri and P. diminuta can grow at 50°C. Based on research indicates that indigenous fermege bacterial isolates have the ability to grow in the neutral pH range and temperature range between 4°C and 50°C.

Association between antimicrobial resistance in Escherichia coli isolates from food animals and blood stream isolates from humans in Europe: an ecological study.

PubMed

Vieira, Antonio R; Collignon, Peter; Aarestrup, Frank M; McEwen, Scott A; Hendriksen, Rene S; Hald, Tine; Wegener, Henrik C

2011-12-01

In addition to medical antimicrobial usage, the use of antimicrobials in food animals contributes to the occurrence of resistance among some bacterial species isolated from infections in humans. Recently, several studies have indicated that a large proportion of Escherichia coli causing infections in humans, especially those resistant to antimicrobials, have an animal origin. We analyzed the correlation between the prevalence of antimicrobial resistance in E. coli isolates from blood stream infections in humans and in E. coli isolates from poultry, pigs, and cattle between 2005 and 2008 for 11 countries, using available surveillance data. We also assessed the correlation between human antimicrobial usage and the occurrence of resistance in E. coli isolates from blood stream infections. Strong and significant correlations between prevalences of resistance to ampicillin (r=0.94), aminoglycosides (r=0.72), third-generation cephalosporins (r=0.76), and fluoroquinolones (r=0.68) were observed for human and poultry E. coli isolates. Similar significant correlations were observed for ampicillin (r=0.91), aminoglycosides (r=0.73), and fluoroquinolone resistance (r=0.74) in pig and human isolates. In cattle isolates, only ampicillin resistance (r=0.72) was significantly correlated to human isolates. When usage of antimicrobials in humans was analyzed with antimicrobial resistance among human isolates, only correlations between fluoroquinolones (r=0.90) and third-generation cephalosporins (r=0.75) were significant. Resistance in E. coli isolates from food animals (especially poultry and pigs) was highly correlated with resistance in isolates from humans. This supports the hypothesis that a large proportion of resistant E. coli isolates causing blood stream infections in people may be derived from food sources.

Molecular Characterization of Mycobacterium avium subsp. hominissuis of Two Groups of Lymph Nodes, Being Intradermal Tuberculin or Interferon-Gamma Test Positive and Negative, Isolated from Swiss Cattle at Slaughter.

PubMed

Scherrer, Simone; Landolt, Patricia; Carroli, Natasha; Stephan, Roger

2018-01-01

Mycobacterium avium subsp. hominissuis (MAH) is an important zoonotic pathogen with raising global health concerns. In humans, MAH is one of the most widespread non-tuberculous mycobacterial species responsible for lung disease. In animals, MAH is frequently isolated from pigs; however, it is also an opportunistic pathogen for other mammals including cattle. To elucidate the genetic diversity of MAH in cattle, a molecular characterization of isolates ( n  = 26) derived from lymph nodes was performed. Fourteen isolates originated from slaughtered cattle with visible altered lymph nodes at meat inspection, whereas 12 isolates were from lymph nodes without any gross pathological changes of healthy slaughtered cattle. Variable number of tandem repeat (VNTR) analysis was performed at 20 loci to examine genetic differences of isolates and to compare to previously reported VNTR data of human isolates from different countries. Genetic elements IS901, IS1245, IS1311, LSPA17, ITS1 sequevar, and hsp65 code were determined. Interestingly, two bovine MAH isolates harbored ISMav6 and hsp65 code 15, which so far has only been observed in human isolates. We supposed that VNTR data of Swiss samples would show clustering with European samples. Minimum spanning tree and unweighted pair group method using arithmetic averages analyses based on the VNTR data indicated a specific cluster of MAH isolates obtained from lymph nodes without any gross pathological changes of healthy slaughtered cattle. Comparing Swiss isolates with isolates from different other countries, no geographical clustering was observed; however, four Swiss isolates had an identical VNTR profile as human isolates from the Netherlands, the United States, and Japan. These findings indicate a possible public health issue.

[Molecular epidemiology of methicillin-resistant Staphylococcus aureus isolates with toxic shock syndrome toxin and staphylococcal enterotoxin C genes].

PubMed

Kim, Jae Seok; Kim, Han Sung; Song, Wonkeun; Cho, Hyoun Chan; Lee, Kyu Man; Kim, Eui Chong

2007-04-01

Many methicillin-resistant Staphylococcus aureus (MRSA) isolates in Korea possess a specific profile of staphylococcal enterotoxins in that the toxic shock syndrome toxin gene (tst) coexists with the staphylococcal enterotoxin C gene (sec). Because the analysis of staphylococcal cassette chromosome mec (SCCmec), a mobile genetic element mecA gene encoding methicillin resistance, showed that majority of these are SCCmec type II, these MRSA isolates with tst and sec may be genetically related with each other. This study was performed to investigate the genetic relatedness of tstand sec-harboring MRSA strains isolated in Korea by using pulsed-field gel electrophoresis (PFGE). A total of 59 strains of MRSA isolates of SCCmec type II possessing tst and sec were selected for PFGE and phylogenetic analyses. These isolates were collected from 13 health care facilities during nationwide surveillance of antimicrobial resistance in 2002. The 59 MRSA isolates were clustered into 11 PFGE types, including one major group of 26 strains (44.1%) isolated from 7 healthcare facilities. Seven PFGE types contained 2 or more isolates each, comprising 55 isolates in total. Most of SCCmec type II MRSA isolates containing tst and sec showed closely related PFGE patterns. Moreover, MRSA isolates collected from different healthcare facilities showed identical PFGE patterns. These findings suggested a clonal spread of MRSA strains possessing tst and sec in Korean hospitals.

Performance of CarbaNP and CIM tests in OXA-48 carbapenemase-producing Enterobacteriaceae.

PubMed

Yıldız, Serap Süzük; Kaşkatepe, Banu; Avcıküçük, Havva; Öztürk, Şükran

2017-03-01

This study applied two phenotypic tests, namely "Carbapenemase Nordmann-Poirel" (CarbaNP) test and "Carbapenem Inactivation Method" (CIM), against the isolates carrying the carbapenem resistance genes. The study included 83 carbapenem-resistant Enterobacteriaceae isolates producing oxacillinase-48 (OXA-48) and 30 carbapenem-sensitive Enterobacteriaceae isolates. Out of the total isolates studied, 77 isolates (92.77%) were identified as Klebsiella pneumoniae and six isolates (7.23%) were identified as Escherichia coli by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry. Polymerase chain reaction (PCR) method used to detect resistance genes found that 74 isolates (89.16%) produced OXA-48 carbapenemase, whereas nine isolates (10.84%) produced both OXA-48 and New Delhi metallo-beta-lactamase-1 (NDM-1). The isolates producing both OXA-48 and NDM-1 were found to be positive by both phenotypic tests. Among isolates carrying only bla OXA-48 gene alone, nine isolates (13.04%) for CarbaNP test and two isolates for CIM test (2.90%) displayed false negative results, respectively. The sensitivity of CarbaNP and CIM tests was found to be 89.16% and 97.59%, respectively, whereas the specificity was determined to be 100% for both tests. These findings suggest that CarbaNP and CIM tests are useful tools to identify the carbapenemase producers. Molecular methods like PCR are recommended to verify false negative tests predicted to have OXA-48 activity.

Trajectories of social isolation in adult survivors of childhood cancer.

PubMed

Howard, A Fuchsia; Tan de Bibiana, Jason; Smillie, Kirsten; Goddard, Karen; Pritchard, Sheila; Olson, Rob; Kazanjian, Arminee

2014-03-01

Long-term childhood cancer survivors may be at increased risk for poor social outcomes as a result of their cancer treatment, as well as physical and psychological health problems. Yet, important challenges, namely social isolation, are not well understood. Moreover, survivors' perspectives of social isolation as well as the ways in which this might evolve through young adulthood have yet to be investigated. The purpose of this research was to describe the trajectories of social isolation experienced by adult survivors of a childhood cancer. Data from 30 in-depth interviews with survivors (9 to 38 years after diagnosis, currently 22 to 43 years of age, 60 % women) were analyzed using qualitative, constant comparative methods. Experiences of social isolation evolved over time as survivors grew through childhood, adolescence and young adulthood. Eleven survivors never experienced social isolation after their cancer treatment, nor to the present day. Social isolation among 19 survivors followed one of three trajectories; (1) diminishing social isolation: it got somewhat better, (2) persistent social isolation: it never got better or (3) delayed social isolation: it hit me later on. Knowledge of when social isolation begins and how it evolves over time for different survivors is an important consideration for the development of interventions that prevent or mitigate this challenge. Assessing and addressing social outcomes, including isolation, might promote comprehensive long-term follow-up care for childhood cancer survivors.

Xylella fastidiosa Isolates from Both subsp. multiplex and fastidiosa Cause Disease on Southern Highbush Blueberry (Vaccinium sp.) Under Greenhouse Conditions.

PubMed

Oliver, J E; Cobine, P A; De La Fuente, L

2015-07-01

Xylella fastidiosa is a xylem-limited gram-negative plant pathogen that affects numerous crop species, including grape, citrus, peach, pecan, and almond. Recently, X. fastidiosa has also been found to be the cause of bacterial leaf scorch on blueberry in the southeastern United States. Thus far, all X. fastidiosa isolates obtained from infected blueberry have been classified as X. fastidiosa subsp. multiplex; however, X. fastidiosa subsp. fastidiosa isolates are also present in the southeastern United States and commonly cause Pierce's disease of grapevines. In this study, seven southeastern U.S. isolates of X. fastidiosa, including three X. fastidiosa subsp. fastidiosa isolates from grape, one X. fastidiosa subsp. fastidiosa isolate from elderberry, and three X. fastidiosa subsp. multiplex isolates from blueberry, were used to infect the southern highbush blueberry 'Rebel'. Following inoculation, all isolates colonized blueberry, and isolates from both X. fastidiosa subsp. multiplex and X. fastidiosa subsp. fastidiosa caused symptoms, including characteristic stem yellowing and leaf scorch symptoms as well as dieback of the stem tips. Two X. fastidiosa subsp. multiplex isolates from blueberry caused more severe symptoms than the other isolates examined, and infection with these two isolates also had a significant impact on host mineral nutrient content in sap and leaves. These findings have potential implications for understanding X. fastidiosa host adaptation and expansion and the development of emerging diseases caused by this bacterium.

Non-Tuberculous Mycobacteria. An Emerging Threat?

PubMed

Martínez González, Susana; Cano Cortés, Arantxa; Sota Yoldi, Luis Alfonso; García García, José María; Alba Álvarez, Luz María; Palacios Gutiérrez, Juan José

2017-10-01

Non-tuberculous mycobacteria (NTM) isolates are becoming more common. The main objective of our study was to establish the number and diversity of NTM species in our region and their distribution according to the source sample, age and gender of the patients, and to analyse clinically significant isolates. Prospective study of all NTM isolated in Asturias from 2005 to 2012. Samples were processed following internationally accepted guidelines. Statistical analysis was based on Fisher's exact test for 2×2 contingency tables. A total of 3,284 mycobacteria were isolated: 1,499 Mycobacterium tuberculosis complex (MTB) and 1,785 NTM.During the study, NTM isolation rates increased while MTB isolation decreased. NTM were more frequent in men (P<.001). M.gordonae was the most frequently isolated species but did not cause disease in any case. NTM isolates from 212 patients were associated with clinically significant disease (17.1%). M.kansasii and M.avium were most commonly associated with disease. The number of M.kansasii isolates from men was statistically significant (P<.01). In our study, NTM isolates increased by 35%, compared with a 21% decline in cases of MTB. Both isolation of NTM and clinically significant cases were more common in men. Only 17.1% of NTM isolates were associated with disease, most commonly M.avium complex and M.kansasii. Copyright © 2017 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

Characterization of carbapenem nonsusceptible Pseudomonas aeruginosa in Denmark: a nationwide, prospective study.

PubMed

Hansen, Frank; Johansen, Helle Krogh; Østergaard, Claus; Arpi, Magnus; Hansen, Dennis Schrøder; Littauer, Pia; Holm, Anette; Heltberg, Ole; Schumacher, Helga; Fuursted, Kurt; Lykke, Mari-Ann Domar; Tønning, Birgitte; Hammerum, Anette M; Justesen, Ulrik Stenz

2014-02-01

From January 1st 2011 through June 30th 2011, 116 nonreplicate, noncystic fibrosis-related Pseudomonas aeruginosa isolates with reduced carbapenem susceptibility were collected from 12 out of 13 Danish departments of clinical microbiology. The presence of acquired β-lactamases was assessed with combination tablet-diffusion methodology and polymerase chain reaction. In addition, antimicrobial susceptibility testing, an efflux pump inhibitor assay, and pulsed-field gel electrophoresis (PFGE) were performed. Isolates producing acquired β-lactamases were further investigated by serotyping and multi locus sequence typing. Eight isolates produced the metallo-β-lactamase (MBL) VIM-2, and one isolate produced OXA-10 and VEB-1-like extended-spectrum beta-lactamase (ESBL). Phenotypic indications of derepressed AmpC and efflux pump were seen in 56 and 43 isolates, respectively. Overall, the results indicate that mutational factors related to permeability--often combined with derepressed, chromosomal AmpC--is the main factor behind carbapenem nonsusceptibility in Danish P. aeruginosa isolates. The ESBL producer and all the VIM producers belonged to international clones. PFGE revealed that most of the isolates were unrelated, but clonal spread was seen; the 116 isolates distributed in 97 PFGE types, with the largest cluster consisting of 4 isolates (including three isolates from the same hospital with 100% similarity). Thirty-two isolates were pair-wise related, while the remaining isolates were clonally unrelated, as were all nine ESBL/MBL producers.

Molecular epidemiology and clinical implications of metallo-β-lactamase-producing Pseudomonas aeruginosa isolated from urine.

PubMed

Sako, Shinichi; Kariyama, Reiko; Mitsuhata, Ritsuko; Yamamoto, Masumi; Wada, Koichiro; Ishii, Ayano; Uehara, Shinya; Kokeguchi, Susumu; Kusano, Nobuchika; Kumon, Hiromi

2014-01-01

We conducted a study on molecular epidemiology and clinical implications of metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa isolated from urine. Over a 10-year period from 2001 through 2010, a total of 92 MBL-producing P. aeruginosa urine isolates were collected from patients (one isolate per patient) who were admitted to 5 hospitals in Okayama Prefecture, Japan. When cross-infection was suspected in the hospital, pulsed-field gel electrophoresis was performed. In the resulting dendrogram of 79 MBL-producing P. aeruginosa urine isolates, no identical isolates and 7 pairs of isolates with >80% similarity were found. The biofilm-forming capabilities of 92 MBL-producing P. aeruginosa urine isolates were significantly greater than those of 92 non-MBL-producing urine isolates in a medium of modified artificial urine. The imipenem resistance transferred in 16 of 18 isolates tested, and these frequencies were in the range of 10⁻³ to 10⁻⁹. All of 18 isolates tested belonged to internationally spread sequence type 235 and had 3 gene cassettes of antimicrobial resistance genes in the class 1 integron. The strong biofilm-forming capabilities of MBL-producing P. aeruginosa urine isolates could be seriously implicated in nosocomial infections. To prevent spread of the organism and transferable genes, effective strategies to inhibit biofilm formation in medical settings are needed.

Prevalence and antimicrogram of Staphylococcus intermedius group isolates from veterinary staff, companion animals, and the environment in veterinary hospitals in Korea.

PubMed

Youn, Jung-Ho; Yoon, Jang Won; Koo, Hye Cheong; Lim, Suk-Kyung; Park, Yong Ho

2011-03-01

The Staphylococcus intermedius bacterial group (SIG) includes 3 distinct genetically heterogenous species: S. intermedius, S. pseudintermedius, and S. delphini. This pathogen group is associated with many opportunistic skin and ear infections in companion animals. Human infections with S. intermedius and S. pseudintermedius isolates and the emergence of methicillin-resistant isolates have been recently reported, which emphasizes the importance of nationwide identification of SIG isolate prevalence and antibiotic resistance in veterinary clinics. In the present study, a total of 178 SIG isolates were obtained from veterinary staff (n  =  40), companion animals (n  =  115), and the local environment (n  =  23) in 8 Korean veterinary hospitals. Isolates were differentiated into 167 S. pseudintermedius (93.8%) and 11 S. intermedius (6.2%) isolates; S. delphini isolates were not identified. The most effective antibiotics against these isolates included amoxicillin-clavulanic acid, amikacin, nitrofloxacin, imipenem, and vancomycin; whereas ampicillin, penicillin, tetracycline, erythromycin, and trimethoprim-sulfamethoxazole were not effective. Surprisingly, the 128 SIG isolates (71.9%) displayed multiple drug resistance (MDR) against 3 or more antibiotic classes. Out of 52 SIG isolates carrying the methicillin-resistance gene (mecA), only 34 (65.4%) were oxacillin-resistant, and 49 (94.2%) methicillin-resistant SIG were multidrug resistant. This finding suggests the presence of greater numbers of MDR phenotypes than other isolates (P < 0.05).

Increased frequency of self-fertile isolates in Phytophthora infestans may attribute to their higher fitness relative to the A1 isolates

PubMed Central

Zhu, Wen; Shen, Lin-Lin; Fang, Zhi-Guo; Yang, Li-Na; Zhang, Jia-Feng; Sun, Dan-Li; Zhan, Jiasui

2016-01-01

Knowledge of population dynamics of mating types is important for better understanding pathogen’s evolutionary potential and sustainable management of natural and chemical resources such as host resistances and fungicides. In this study, 2250 Phytophthora infestans isolates sampled from 61 fields across China were assayed for spatiotemporal dynamics of mating type frequency. Self-fertile isolates dominated in ~50% of populations and all but one cropping region with an average frequency of 0.64 while no A2 isolates were detected. Analyses of 140 genotypes consisting of 82 self-fertile and 58 A1 isolates indicated that on average self-fertile isolates grew faster, demonstrated higher aggressiveness and were more tolerant to fungicides than A1 isolates; Furthermore, pattern of association between virulence complexity (defined as the number of differential cultivars on which an isolate can induce disease) and frequency was different in the two mating types. In A1 isolates, virulence complexity was negatively correlated (r = −0.515, p = 0.043) with frequency but this correlation was positive (r = 0.532, p = 0.037) in self-fertile isolates. Our results indicate a quick increase of self-fertile isolates possibly attributable to their higher fitness relative to A1 mating type counterpart in the field populations of P. infestans in China. PMID:27384813

The potential of bacteria isolated from ruminal contents of seaweed-eating North Ronaldsay sheep to hydrolyse seaweed components and produce methane by anaerobic digestion in vitro.

PubMed

Williams, Allan G; Withers, Susan; Sutherland, Alastair D

2013-01-01

The production of methane biofuel from seaweeds is limited by the hydrolysis of polysaccharides. The rumen microbiota of seaweed-eating North Ronaldsay sheep was studied for polysaccharidic bacterial isolates degrading brown-seaweed polysaccharides. Only nine isolates out of 65 utilized >90% of the polysaccharide they were isolated on. The nine isolates (eight Prevotella spp. and one Clostridium butyricum) utilized whole Laminaria hyperborea extract and a range of seaweed polysaccharides, including alginate (seven out of nine isolates), laminarin and carboxymethylcellulose (eight out of nine isolates); while two out of nine isolates additionally hydrolysed fucoidan to some extent. Crude enzyme extracts from three of the isolates studied further had diverse glycosidases and polysaccharidase activities; particularly against laminarin and alginate (two isolates were shown to have alginate lyase activity) and notably fucoidan and carageenan (one isolate). In serial culture rumen microbiota hydrolysed a range of seaweed polysaccharides (fucoidan to a notably lesser degree) and homogenates of L. hyperborea, mixed Fucus spp. and Ascophyllum nodosum to produce methane and acetate. The rumen microbiota and isolates represent potential adjunct organisms or enzymes which may improve hydrolysis of seaweed components and thus improve the efficiency of seaweed anaerobic digestion for methane biofuel production. © 2012 The Authors. Microbial Biotechnology © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Relationships among North American and Japanese Laetiporus isolates inferred from molecular phylogenetics and single-spore incompatibility reactions

Treesearch

Mark T. Banik; Daniel L. Lindner; Yuko Ota; Tsutomu Hattori

2010-01-01

Relationships were investigated among North American and Japanese isolates of Laetiporus using phylogenetic analysis of ITS sequences and single-spore isolate incompatibility. Single-spore isolate pairings revealed no significant compatibility between North American and Japanese isolates. ITS analysis revealed 12 clades within the core ...

Improved RF Isolation Amplifier

NASA Technical Reports Server (NTRS)

Stevens, G. L.; Macconnell, J.

1985-01-01

Circuit has high reverse isolation and wide bandwidth. Wideband isolation amplifier has low intermodulation distortion and high reverse isolation. Circuit does not require selected or matched components or directional coupling device. Circuit used in applications requiring high reverse isolation such as receiver intermediate-frequency (IF) strips and frequency distribution systems. Also applicable in RF and video signaling.

Chromobacterium sphagni sp. nov., an insecticidal bacterium isolated from Sphagnum bogs

USDA-ARS?s Scientific Manuscript database

Sixteen isolates of Gram-negative, motile, violet-pigmented bacteria were isolated from Sphagnum bogs in West Virginia and Maine, USA. 16S rDNA sequences and fatty acid analysis (FAME) revealed a high degree of relatedness among the isolates, and genomic sequencing of two isolates, IIBBL 14B-1 and I...

In Vitro Susceptibilities of Mycoplasma hyopneumoniae Field Isolates

PubMed Central

Vicca, J.; Stakenborg, T.; Maes, D.; Butaye, P.; Peeters, J.; de Kruif, A.; Haesebrouck, F.

2004-01-01

The in vitro susceptibilities of 21 Mycoplasma hyopneumoniae field isolates were determined using a broth microdilution technique. One isolate showed acquired resistance to lincomycin, tilmicosin, and tylosin, while five isolates were resistant to flumequine and enrofloxacin. Acquired resistance against these antimicrobials in M. hyopneumoniae field isolates was not reported previously. PMID:15504886

Phenotypic and genotypic evaluation of fluoroquinolone resistance in clinical isolates of Staphylococcus aureus in Tehran

PubMed Central

Aligholi, Marzieh; Mirsalehian, Akbar; Halimi, Shahnaz; Imaneini, Hossein; Taherikalani, Morovat; Jabalameli, Fereshteh; Asadollahi, Parisa; Mohajer, Babak; Abdollahi, Alireza; Emaneini, Mohammad

2011-01-01

Summary Background Fluoroquinolones are broad-spectrum antibiotics widely used in the treatment of bacterial infections such as Staphylococcus aureus isolates. Resistance to these antibiotics is increasing. Material/Methods The occurrence of mutations in the grlA and gyrA loci were evaluated in 69 fluoroquinolone-resistant S. aureus isolates from 2 teaching hospitals of Tehran University of Medical Sciences. Results Out of the 165 S. aureus isolates, 87 (52.7%) were resistant to methicillin and 69 (41.8%) were resistant to fluoroquinolone. Fluoroquinolone-resistant S. aureus isolates had a mutation at codon 80 in the grlA gene and different mutational combinations in the gyrA gene. These mutational combinations included 45 isolates at codons 84 and 86, 23 isolates at codons 84, 86 and 106 and 1 isolate at codons 84, 86 and 90. Fluoroquinolone-resistant S. aureus isolates were clustered into 33 PFGE types. Conclusions The findings of this study show that the fluoroquinolone-resistant S. aureus strains isolated in the teaching hospitals in Tehran had multiple mutations in the QRDRs region of both grlA and gyrA genes. PMID:21873957

Phenotypic and genotypic evaluation of fluoroquinolone resistance in clinical isolates of Staphylococcus aureus in Tehran.

PubMed

Aligholi, Marzieh; Mirsalehian, Akbar; Halimi, Shahnaz; Imaneini, Hossein; Taherikalani, Morovat; Jabalameli, Fereshteh; Asadollahi, Parisa; Mohajer, Babak; Abdollahi, Alireza; Emaneini, Mohammad

2011-09-01

Fluoroquinolones are broad-spectrum antibiotics widely used in the treatment of bacterial infections such as Staphylococcus aureus isolates. Resistance to these antibiotics is increasing. The occurrence of mutations in the grlA and gyrA loci were evaluated in 69 fluoroquinolone-resistant S. aureus isolates from 2 teaching hospitals of Tehran University of Medical Sciences. Out of the 165 S. aureus isolates, 87 (52.7%) were resistant to methicillin and 69 (41.8%) were resistant to fluoroquinolone. Fluoroquinolone-resistant S. aureus isolates had a mutation at codon 80 in the grlA gene and different mutational combinations in the gyrA gene. These mutational combinations included 45 isolates at codons 84 and 86, 23 isolates at codons 84, 86 and 106 and 1 isolate at codons 84, 86 and 90. Fluoroquinolone-resistant S. aureus isolates were clustered into 33 PFGE types. The findings of this study show that the fluoroquinolone-resistant S. aureus strains isolated in the teaching hospitals in Tehran had multiple mutations in the QRDRs region of both grlA and gyrA genes.

Recent advances in micro-vibration isolation

NASA Astrophysics Data System (ADS)

Liu, Chunchuan; Jing, Xingjian; Daley, Steve; Li, Fengming

2015-05-01

Micro-vibration caused by disturbance sources onboard spacecraft can severely degrade the working environment of sensitive payloads. Some notable vibration control methods have been developed particularly for the suppression or isolation of micro-vibration over recent decades. Usually, passive isolation techniques are deployed in aerospace engineering. Active isolators, however, are often proposed to deal with the low frequency vibration that is common in spacecraft. Active/passive hybrid isolation has also been effectively used in some spacecraft structures for a number of years. In semi-active isolation systems, the inherent structural performance can be adjusted to deal with variation in the aerospace environment. This latter approach is potentially one of the most practical isolation techniques for micro-vibration isolation tasks. Some emerging advanced vibration isolation methods that exploit the benefits of nonlinearity have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of the vibration isolation theory and/or methods which were developed, mainly over the last decade, specifically for or potentially could be used for, micro-vibration control.

Regional Spread of CTX-M-2-Producing Proteus mirabilis with the Identical Genetic Structure in Japan.

PubMed

Kato, Karin; Matsumura, Yasufumi; Yamamoto, Masaki; Nagao, Miki; Takakura, Shunji; Ichiyama, Satoshi

2017-07-01

In this study, we analyzed the molecular epidemiology of extended-spectrum β-lactamase (ESBL)-producing Proteus mirabilis isolates collected from the central region of Japan. Between 2005 and 2012, 820 clinical P. mirabilis isolates were obtained from ten acute care hospitals in Japan. We characterized ESBL confirmatory test-positive isolates by sequencing the ESBL genes and their flanking regions, detecting plasmid replicons, and performing pulsed-field gel electrophoresis (PFGE). Ninety-six isolates (12%) were positive according to the ESBL confirmatory test; all these isolates possessed bla CTX-M-2 with the same flanking structure of upstream ΔISEcp1 and a downstream region identical to downstream bla KLUA-1 . IncT was the prevalent, and only, replicon found in 63 isolates. PFGE analysis detected eight clusters with more than one isolate, among which three included 56 isolates and six included isolates from multiple hospitals. CTX-M-2-producing P. mirabilis with an identical genetic structure flanking bla CTX-M-2 is dominant in this Japanese region, and there is evidence for the clonal spread of isolates.

The Epidemiology of Social Isolation: National Health & Aging Trends Study.

PubMed

Cudjoe, Thomas K M; Roth, David L; Szanton, Sarah L; Wolff, Jennifer L; Boyd, Cynthia M; Thorpe, Roland J

2018-03-26

Social isolation among older adults is an important but under-recognized risk for poor health outcomes. Methods are needed to identify subgroups of older adults at risk for social isolation. We constructed a typology of social isolation using data from the National Health and Aging Trends Study (NHATS) and estimated the prevalence and correlates of social isolation among community-dwelling older adults. The typology was formed from four domains: living arrangement, core discussion network size, religious attendance, and social participation. In 2011, 24% of self-responding, community-dwelling older adults (65+ years), approximately 7.7 million people, were characterized as socially isolated, including 1.3 million (4%) who were characterized as severely socially isolated. Multinomial multivariable logistic regression indicated that being unmarried, male, having low education, and low income were all independently associated with social isolation. Black and Hispanic older adults had lower odds of social isolation compared to White older adults, after adjusting for covariates. Social isolation is an important and potentially modifiable risk that affects a significant proportion of the older adult population.

Human isolates of Listeria monocytogenes in Sweden during half a century (1958-2010).

PubMed

Lopez-Valladares, G; Tham, W; Parihar, V Singh; Helmersson, S; Andersson, B; Ivarsson, S; Johansson, C; Ringberg, H; Tjernberg, I; Henriques-Normark, B; Danielsson-Tham, M-L

2014-11-01

Isolates of Listeria monocytogenes (n = 932) isolated in Sweden during 1958-2010 from human patients with invasive listeriosis were characterized by serotyping and pulsed-field gel electrophoresis (PFGE) (AscI). Of the 932 isolates, 183 different PFGE types were identified, of which 83 were each represented by only one isolate. In all, 483 serovar 1/2a isolates were distributed over 114 PFGE types; 90 serovar 1/2b isolates gave 32 PFGE types; 21 serovar 1/2c isolates gave nine PFGE types; three serovar 3b isolates gave one PFGE type; and, 335 serovar 4b isolates gave 31 PFGE types. During the 1980s in Sweden, several serovar 4b cases were associated with the consumption of European raw soft cheese. However, as cheese-production hygiene has improved, the number of 4b cases has decreased. Since 1996, serovar 1/2a has been the dominant L. monocytogenes serovar in human listeriosis in Sweden. Therefore, based on current serovars and PFGE types, an association between human cases of listeriosis and the consumption of vacuum-packed gravad and cold-smoked salmon is suggested.

Engine isolation for structural-borne interior noise reduction in a general aviation aircraft

NASA Technical Reports Server (NTRS)

Unruh, J. F.; Scheidt, D. C.

1981-01-01

Engine vibration isolation for structural-borne interior noise reduction is investigated. A laboratory based test procedure to simulate engine induced structure-borne noise transmission, the testing of a range of candidate isolators for relative performance data, and the development of an analytical model of the transmission phenomena for isolator design evaluation are addressed. The isolator relative performance test data show that the elastomeric isolators do not appear to operate as single degree of freedom systems with respect to noise isolation. Noise isolation beyond 150 Hz levels off and begins to decrease somewhat above 600 Hz. Coupled analytical and empirical models were used to study the structure-borne noise transmission phenomena. Correlation of predicted results with measured data show that (1) the modeling procedures are reasonably accurate for isolator design evaluation, (2) the frequency dependent properties of the isolators must be included in the model if reasonably accurate noise prediction beyond 150 Hz is desired. The experimental and analytical studies were carried out in the frequency range from 10 Hz to 1000 Hz.

Antimicrobial susceptibility of Clostridium perfringens isolates of bovine, chicken, porcine, and turkey origin from Ontario

PubMed Central

Slavić, Đurđa; Boerlin, Patrick; Fabri, Marta; Klotins, Kim C.; Zoethout, Jennifer K.; Weir, Pat E.; Bateman, Debbie

2011-01-01

Antimicrobial susceptibilities and toxin types were determined for 275 Clostridium perfringens isolates collected in Ontario in the spring of 2005. Minimal inhibitory concentrations (MICs) of C. perfringens isolates for 12 antimicrobials used in therapy, prophylaxis, and/or growth promotion of cattle (n = 40), swine (n = 75), turkeys (n = 50), and chickens (n = 100) were determined using the microbroth dilution method. Statistical analyses and MIC distributions showed reduced susceptibility to bacitracin, clindamycin, erythromycin, florfenicol, and tetracycline for some isolates. Reduced susceptibility to bacitracin was identified in chicken (64%) and turkey (60%) isolates. Swine isolates had predominantly reduced susceptibility to clindamycin (28%) and erythromycin (31%), whereas bovine isolates had reduced susceptibility to clindamycin (10%) and florfenicol (10%). Reduced susceptibility to tetracycline was spread across all species. No clear reduced susceptibility, but elevated MIC50 for virginiamycin was found in chicken isolates in comparison with isolates from other species. Toxin typing revealed that C. perfringens type A is the dominant toxin type isolated in this study across all 4 host species. PMID:21731178

Isolation and identification of cellulolytic bacteria from termites gut (Cryptotermes sp.)

NASA Astrophysics Data System (ADS)

Peristiwati; Natamihardja, Y. S.; Herlini, H.

2018-05-01

The energy and environmental crises developed due to a huge amount of cellulosic materials are disposed of as “waste.” Cellulose is the most abundant biopolymer on Earth. The hydrolysis of cellulose to glucose and soluble sugars has thus become a subject of intense research. Termites are one of the most important soil insects that efficiently decompose lignocelluloses with the aid of their associated microbial symbionts to a simpler form of sugars. The steps of this study consisted of cellulose isolation, cellulolytic bacteria isolation and identification. Cellulose degrading bacteria from termite (Cryptotermes sp.) gut flora were isolated, screened and their identification was studied which showed halo zones due to CMC agar. Among 12 isolates of bacteria, six isolates were cellulolytic. MLC-A isolate had shown a maximum in a cellulolytic index (1.32). Each isolate was identified based on standard physical and biochemical tests. Three isolates were identified in the genus of Clostridium, one isolate be placed in the group of Mycobacteriaceae, Lactobacillaceae or Coryneform and the last one in the genus Proteus.

Emergence of new strains of Watermelon mosaic virus in South-eastern France: evidence for limited spread but rapid local population shift.

PubMed

Desbiez, C; Joannon, B; Wipf-Scheibel, C; Chandeysson, C; Lecoq, H

2009-05-01

Severe symptoms caused by Watermelon mosaic virus (WMV) in zucchini squash leaves and fruits have been observed since 1999 in South-eastern (SE) France. Their appearance correlates with the introduction of new, "emerging" (EM) isolates distant at the molecular level from the "classic" (CL) isolates present for more than 30 years. To understand the origin and spread of EM isolates, a survey was performed between 2004 and 2007. WMV isolates collected were characterized by sequencing part of the polymerase and coat protein coding regions. This revealed the presence of EM isolates in SE France only, whereas CL isolates were widespread throughout the country. Besides, four subgroups of EM isolates were observed in SE France, suggesting multiple introductions. Recombinants between CL and EM groups, which probably arose locally, were observed during the survey. A strong geographic structure that remained stable during the 4 years was observed between different EM isolates. Our results showed that EM isolates did not spread over long distances, but rapidly replaced the pre-existing CL isolates in all sites where both groups occurred.

RAPD cluster analysis and chlorate sensitivity of some Indian isolates of Macrophomina phaseolina from sorghum and their relationships with pathogenicity.

PubMed

Das, I K; Fakrudin, B; Arora, D K

2008-01-01

Charcoal rot caused by Macrophomina phaseolina is an economically important disease in sorghum grown during the post rainy season in India. Variations in random amplified polymorphic DNA (RAPD) polymorphisms, chlorate sensitivity and pathogenicity were studied among sorghum isolates of M. phaseolina collected from different parts of India. RAPD data based on 14 random primers of Kit A and C (OPA and OPC) on 20 isolates showed a high degree of polymorphism (98.1%) in different isolates. UPGMA dendrogram on RAPD data produced 7 clusters at the level of 37% similarity. Isolates from the same locations showed a tendency to group closer, substantiating closer genetic relatedness. Sorghum infecting Macrophomina isolates showed a mixed response for sensitivity to potassium chlorate (120 mM). Chlorate-resistant isolates were predominant (>65% of the isolates) over sensitive isolates. Chlorate-sensitive isolates were found to be genetically closer among them than the resistant ones. For the first time it was shown that chlorate sensitivity in Macrophomina had some relations with charcoal rot severity in sorghum.

Isolation and molecular identification of echovirus 13 isolated from patients of aseptic meningitis in Korea, 2002.

PubMed

Cheon, Doo-Sung; Lee, Jiwon; Lee, Kangbum; Lee, Sunhwa; Park, Kwisung; Ahn, Jungbae; Jee, Youngmee; Yoon, Jaedeuk; Cho, Haewol

2004-07-01

During 2002, several epidemics of aseptic meningitis were attributed to echovirus 13 in Korea. The causative agents of these outbreaks were isolated and identified using rhabdosarcoma cells, HEp-2 and Buffalo green monkey kidney cells, and a neutralization test using monospecific antiserum. Fifty-four echovirus 13 isolates were isolated from patients with aseptic meningitis in the provinces, Seoul, Kyonggi, Gwangju, Jeonju, Busan, and Ulsan. Symptoms associated with aseptic meningitis infection in patients included the occurrence of headaches and mild fever. Molecular characterization of echovirus 13 samples was achieved by sequence and phylogenetic analyses on partial VP1 sequences from 20 Korean isolates and 10 foreign isolates listed in Genbank. Minor variation was observed among the Korean isolates, which formed a unique cluster with isolates of German and Japanese origin. The marked similarities between isolates could be attributed to a relatively recent arrival of the virus in Korea. This is the first such investigation of aseptic meningitis caused by echovirus 13 on the Korean peninsula. Copyright 2004 Wiley-Liss, Inc.

Fungal endophytes characterization from four species of Diplazium Swartz

NASA Astrophysics Data System (ADS)

Affina-Eliya, A. A.; Noraini, T.; Nazlina, I.; Ruzi, A. R.

2014-09-01

Four species on genus Diplazium namely Diplazium tomentosum, D. sorzogonense, D. asperum and D. accedens of Peninsular Malaysia were studied for presence of fungal endophyte. The objective of this study is to characterize fungal endophytes in the rhizome of four Diplazium species. The rhizome was surface sterilized and incubated to isolate fungal endophytes. Characterization of the colonies was performed by macroscopic morphological, microscopic identification, types of hyphae and mycelium, and spore structure. For isolation that produces spores, the structure of conidiophores and conidia were identified. From this study, four fungal have been isolated and determined as Aspergillus sp. (isolates AE 1), Aspergillus fumigatus (isolates AE 2), Aspergillus versicolor (isolates AE 3) and Verticillium sp. (isolates AE 4). The fungal isolates from this study were classified from the same family Moniliaceae.

Isolation and identification of gold nanoparticles synthesizing fungi from Indian Kolar Gold Field mine soil.

PubMed

Lakshmi, V Jhansi; Kannan, K P

2016-07-01

An indigenous fungal strain was isolated from Indian Kolar Gold Field mine soil. The isolate was heterothallic, branched septate, deeply floccose, fast-growing, dull green with white background conidial columnar mycelium from Aspergillus section Fumigati. Diverse metabolic patterns of the isolate exhibit high metal, thermal resistance which grews well from 28 ± 1 degrees C to 37 degrees C and pH concentration was significant on the growth of isolate. Phylogenetic analysis of 16srRNA β-Tubulin gene sequence established relationship among isolate and other taxa. Molecular identification and morphological features of fungal isolate were consistent with those of Neosartorya udagawae. Heterothallic N. udagawae FJ830683 strain was closely related to homothallic N. aureola EF661890. Fungal isolate extract synthesized narrow sized stable Gold nanoparticles (AuNPs).

Isolation of copper-binding proteins from activated sludge culture.

PubMed

Fukushi, K; Kato, S; Antsuki, T; Omura, T

2001-01-01

Six copper-binding microbial proteins were isolated from activated sludge cultures grown on media containing copper at various concentrations. Molecular weights among isolated proteins were ranged from 1.3k to 1 74k dalton. Isolated proteins were compared for their copper binding capabilities. Proteins isolated from cultures grown in the presence of copper in the growth media exhibited higher copper binding capabilities than those isolated from the culture grown in the absence of copper. The highest metal uptake of 61.23 (mol copper/mol protein) was observed by a protein isolated from a culture grown with copper at a concentration of 0.25 mM. This isolated protein (CBP2) had a molecular weight of 24k dalton. Other protein exhibited copper binding capability of 4.8-32.5 (mol copper/mol protein).

A new genotype of lymphocystivirus, LCDV-RF, from lymphocystis diseased rockfish.

PubMed

Kitamura, S-I; Jung, S-J; Kim, W-S; Nishizawa, T; Yoshimizu, M; Oh, M-J

2006-03-01

Lymphocystis disease virus (LCDV) is the causative agent of lymphocystis disease. In this study, nucleotide sequences of the major capsid protein (MCP) gene were analyzed among LCDV isolates from Japanese flounder and rockfish. A phylogenetic tree revealed three clusters for lymphocystiviruses. The first cluster included Japanese flounder isolates; the second cluster consisted of rockfish isolates; and the remaining one consisted of LCDV-1. Nucleotide sequence identities were > or =99.6% among Japanese flounder isolates and 100% among rockfish isolates, while between each cluster they were < or =85.2%. Experimental infections with Japanese flounder and rockfish isolates revealed that Japanese flounder and rockfish were infected by the respective homologous isolate but not by the heterologous isolate. These findings suggest that at least three genotypes exist in the genus Lymphocystivirus.

Fine typing of methicillin-resistant Staphylococcus aureus isolates using direct repeat unit and staphylococcal interspersed repeat unit typing methods.

PubMed

Ho, Cheng-Mao; Ho, Mao-Wang; Li, Chi-Yuan; Lu, Jang-Jih

2015-08-01

Methicillin-resistant Staphylococcus aureus (MRSA) typing is an important epidemiologic tool for monitoring trends and preventing outbreaks. However, the efficiency of various MRSA typing methods for each SCCmec MRSA isolate is rarely evaluated. A total of 157 MRSA isolates from four different regions in Taiwan were typed with five different molecular methods, including SCCmec typing, multilocus sequence typing (MLST), spa typing, mec-associated direct repeat unit (dru) copy number determination, and staphylococcal interspersed repeat unit (SIRU) profiling. There were four SCCmec types, eight MLST types, 15 spa types, 11 dru types, and 31 SIRU profiles. The most common type determined by each molecular typing method was SCCmec III (115 isolates, 73.2%), ST239 (99 isolates, 63.1%), t037 (107 isolates, 68.2%), 14 dru copies (76 isolates, 48.4%), and SIRU profile 3013722 (102 isolates, 65%), respectively. When using the combination of MLST, spa typing, and dru copy number, ST5-t002-4 (n = 8), ST239-t037-14 (n = 68), ST59-t437-9 (n = 9), and ST59-t437-11 (n = 6) were found to be the most common types of SCCmec types II (n = 9), III (n = 115), IV (n = 21), and VT (n = 11) isolates, respectively. SCCmec type III isolates were further classified into 11 dru types. Of the 21 SCCmec type IV isolates, 14 SIRU profiles were found. Seven SIRU patterns were observed in the 11 SCCmec type VT isolates. Different typing methods showed a similar Hunter-Gaston discrimination index among the 157 MRSA isolates. However, dru and SIRU typing methods had a better discriminatory power for SCCmec type III and SCCmec types IV and VT isolates, respectively, suggesting that dru and SIRU can be used to further type these isolates. Copyright © 2013. Published by Elsevier B.V.

Using whole genome sequencing to identify resistance determinants and predict antimicrobial resistance phenotypes for year 2015 invasive pneumococcal disease isolates recovered in the United States.

PubMed

Metcalf, B J; Chochua, S; Gertz, R E; Li, Z; Walker, H; Tran, T; Hawkins, P A; Glennen, A; Lynfield, R; Li, Y; McGee, L; Beall, B

2016-12-01

Our whole genome sequence (WGS) pipeline was assessed for accurate prediction of antimicrobial phenotypes. For 2316 invasive pneumococcal isolates recovered during 2015 we compared WGS pipeline data to broth dilution testing (BDT) for 18 antimicrobials. For 11 antimicrobials categorical discrepancies were assigned when WGS-predicted MICs and BDT MICs predicted different categorizations for susceptibility, intermediate resistance or resistance, ranging from 0.9% (tetracycline) to 2.9% (amoxicillin). For β-lactam antibiotics, the occurrence of at least four-fold differences in MIC ranged from 0.2% (meropenem) to 1.0% (penicillin), although phenotypic retesting resolved 25%-78% of these discrepancies. Non-susceptibility to penicillin, predicted by penicillin-binding protein types, was 2.7% (non-meningitis criteria) and 23.8% (meningitis criteria). Other common resistance determinants included mef (475 isolates), ermB (191 isolates), ermB + mef (48 isolates), tetM (261 isolates) and cat (51 isolates). Additional accessory resistance genes (tetS, tet32, aphA-3, sat4) were rarely detected (one to three isolates). Rare core genome mutations conferring erythromycin-resistance included a two-codon rplD insertion (rplD69-KG-70) and the 23S rRNA A2061G substitution (six isolates). Intermediate cotrimoxazole-resistance was associated with one or two codon insertions within folP (238 isolates) or the folA I100L substitution (38 isolates), whereas full cotrimoxazole-resistance was attributed to alterations in both genes (172 isolates). The two levofloxacin-resistant isolates contained parC and/or gyrA mutations. Of 11 remaining isolates with moderately elevated MICs to both ciprofloxacin and levofloxacin, seven contained parC or gyrA mutations. The two rifampin-resistant isolates contained rpoB mutations. WGS-based antimicrobial phenotype prediction was an informative alternative to BDT for invasive pneumococci. Published by Elsevier Ltd.

Fluoroquinolone resistance in Streptococcus pneumoniae isolates in Germany from 2004-2005 to 2014-2015.

PubMed

Schmitz, Julia; van der Linden, Mark; Al-Lahham, Adnan; Levina, Natalia; Pletz, Mathias W; Imöhl, Matthias

2017-06-01

Streptococcus pneumoniae is a major cause of bacterial pneumonia, sepsis and meningitis worldwide. Prevalence of levofloxacin-resistant S. pneumoniae isolates in Germany and associated mutations in the quinolone resistance determining regions (QRDRs), as well as serotype distribution and multi locus sequence types (MLST) are shown. 21,764 invasive S. pneumoniae isolates from Germany, isolated in the epidemiological seasons from 2004/05 to 2014/15 were analyzed at the German National Reference Centre for Streptococci (GNRCS) for their levofloxacin resistance by micro broth dilution method. All resistant (minimal inhibitory concentration (MIC) ≥8μg/ml) and intermediate (MIC >2μg/ml and <8μg/ml) isolates were selected for the present study. Additionally, 29 susceptible isolates were randomly selected. A total of ninety isolates were tested for their levofloxacin-MIC by Etest, their serotype and sequence type, as well as for point-mutations at the QRDRs in the genes parC, parE, gyrA and gyrB. Twenty-five isolates exhibited levofloxacin MICs <2μg/ml (Etest) and no mutations in the QRDRs. Four isolates with MICs=2μg/ml had one mutation in parC; isolates with MICs >2μg/ml all had one or more mutations in the QRDRs. Four of nine intermediate isolates had a mutation in either parC or gyrA, and four isolates had mutations in both parC and gyrB. One isolate had mutations in both parC and gyrA. All isolates with MICs ≥8μg/ml (52) had mutations in both topoisomerase IV and gyrase. Serotypes associated with levofloxacin resistance shifted from a majority of PCV13 serotypes before the introduction of the PCV13 vaccine towards non-PCV serotypes. Resistant isolates were almost exclusively found among adults (98.1%). Copyright © 2017. Published by Elsevier GmbH.

Staphylococcus argenteus from rabbits in Thailand.

PubMed

Indrawattana, Nitaya; Pumipuntu, Natapol; Suriyakhun, Nawarat; Jangsangthong, Arunee; Kulpeanprasit, Suphang; Chantratita, Narisara; Sookrung, Nitat; Chaicumpa, Wanpen; Buranasinsup, Shutipen

2018-06-21

Staphylococcus argenteus, a novel species of the genus Staphylococcus or a member of the S. aureus complex, is closely related to S. aureus and is usually misidentified. In this study, the presence of S. argenteus in isolated S. aureus was investigated in 67 rabbits with abscess lesions during 2014-2016. Among 19 S. aureus complex isolates, three were confirmed to be S. argenteus by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, nonribosomal peptide synthetase gene amplification, and multilocus sequence type. All S. aureus complex isolates, including the S. aureus isolates, were examined for their antimicrobial resistance phenotype by disk diffusion and for their resistance genotype by PCR assays. Among the S. argenteus isolates, one was susceptible to all antimicrobial drugs and the other two were resistant to penicillin and doxycycline. In contrast, most S. aureus isolates were resistant to penicillin (37.5%), and gentamicin (12.5%). Moreover, S. aureus isolates harbored the blaZ, mecA, aacA-aphD, and mrs(A) as well as mutations of gyrA and grlA, but S. argenteus isolates carried solely the blaZ. S. argenteus isolates were investigated for enterotoxin (sea-sed) and virulence genes by PCR. One isolate carried sea, sec, and sed, whereas the other two isolates carried only sea or sed. No isolate carried seb and see. All three S. argenteus isolates carried hla, hlb, and clfA, followed by pvl, whereas coa, spa (IgG-binding region), and spa (x region) were not detected in the three isolates. This paper presents the first identification of S. argenteus from rabbits in Thailand. S. argenteus might be pathogenic because the isolates carried virulence genes. Moreover, antimicrobial resistance was observed. Investigations of this new bacterial species should be conducted in other animal species as well as in humans. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Prevalence and Antimicrobial Resistance of Vibrio parahaemolyticus Isolated from Raw Shellfish in Poland.

PubMed

Lopatek, Magdalena; Wieczorek, Kinga; Osek, Jacek

2015-05-01

Vibrio parahaemolyticus is a marine bacterium recognized as an important cause of gastroenteritis in humans consuming contaminated shellfish. In recent years, increasing resistance to ampicillin and aminoglycosides has been observed among V. parahaemolyticus isolates. However, the first-line antimicrobials such as tetracyclines and fluoroquinolones remained highly effective against these bacteria. The aim of this study was to evaluate the occurrence of V. parahaemolyticus in live bivalve molluscs available on the Polish market and to determine the antimicrobial resistance of the recovered isolates. A total of 400 shellfish samples (mussels, oysters, clams, and scallops) from 2009 to 2012 were tested using the International Organization for Standardization standard 21872-1 method and PCR for the species-specific toxR gene. Antimicrobial susceptibility of the isolates was determined using a microbroth dilution method. V. parahaemolyticus was identified in 70 (17.5%) of the 400 samples, and the toxR gene was confirmed in 64 (91.4%) of these isolates. Most of the isolates were recovered from clams (31 isolates; 48.4% prevalence) followed by mussels (17 isolates; 26.6% prevalence). More V. parahaemolyticus-positive samples were found between May and September (22.7% prevalence) than between October and April (11.4% prevalence). Antibiotic profiling revealed that most isolates were resistant to ampicillin (56 isolates; 87.5%) and to streptomycin (45 isolates; 70.3%), but all of them were susceptible to tetracycline and chloramphenicol. Forty-one isolates (64.1%) were resistant to two or more antimicrobials; however, only one isolate (1.6%) was resistant to three antimicrobial classes. The antimicrobials used in treatment of human V. parahaemolyticus infection had high efficacy against the bacterial isolates tested. This study is the first concerning antibiotic resistance of V. parahaemolyticus isolates in Poland, and the results obtained indicate that these bacteria may pose a health risk to consumers.

Does change in isolated lumbar extensor muscle function correlate with good clinical outcome? A secondary analysis of data on change in isolated lumbar extension strength, pain, and disability in chronic low back pain.

PubMed

Steele, James; Fisher, James; Perrin, Craig; Conway, Rebecca; Bruce-Low, Stewart; Smith, Dave

2018-01-12

Secondary analysis of data from studies utilising isolated lumbar extension exercise interventions for correlations among changes in isolated lumbar extension strength, pain, and disability. Studies reporting isolated lumbar extension strength changes were examined for inclusion criteria including: (1) participants with chronic low back pain, (2) intervention ≥ four weeks including isolated lumbar extension exercise, (3) outcome measures including isolated lumbar extension strength, pain (Visual Analogue Scale), and disability (Oswestry Disability Index). Six studies encompassing 281 participants were included. Correlations among change in isolated lumbar extension strength, pain, and disability. Participants were grouped as "met" or "not met" based on minimal clinically important changes and between groups comparisons conducted. Isolated lumbar extension strength and Visual Analogue Scale pooled analysis showed significant weak to moderate correlations (r = -0.391 to -0.539, all p < 0.001). Isolated lumbar extension strength and Oswestry Disability Index pooled analysis showed significant weak correlations (r = -0.349 to -0.470, all p < 0.001). For pain and disability, isolated lumbar extension strength changes were greater for those "met" compared with those "not met" (p < 0.001-0.008). Improvements in isolated lumbar extension strength may be related to positive and meaningful clinical outcomes. As many other performance outcomes and clinical outcomes are not related, isolated lumbar extension strength change may be a mechanism of action affecting symptom improvement. Implications for Rehabilitation Chronic low back pain is often associated with deconditioning of the lumbar extensor musculature. Isolated lumbar extension exercise has been shown to condition this musculature and also reduce pain and disability. This study shows significant correlations between increases in isolated lumbar extension strength and reductions in pain and disability. Strengthening of the lumbar extensor musculature could be considered an important target for exercise interventions.

Plant growth-promoting potential of bacteria isolated from active volcano sites of Barren Island, India.

PubMed

Amaresan, N; Kumar, K; Sureshbabu, K; Madhuri, K

2014-02-01

To elucidate the biodiversity of plant growth-promoting (PGP) bacteria in active volcano sites of Barren Island, India, a total of 102 bacteria were isolated and screened for their multifunctional PGP properties. The results revealed that 21 isolates (20.6%) survived heat shock at 72°C and 11 (10.8%) isolates were able to grow exposed to 25% NaCl (w/v). In assaying for PGP properties, 59 (57.8%) isolates shown indole acetic acid (IAA) like substances production, 57 isolates (55.9%) produced siderophore and 34 (33.3%) solubilized inorganic phosphate qualitatively. Whereas in the production of extracellular enzymes, 42 isolates (41.2%) produced protease and amylase, 26 (25.5%) isolates produced lipase and 24 (23.5%) isolates produced cellulase. In antagonistic activity, 30 isolates (29.4%) were found antagonistic against Macrophomina sp., 20 isolates (19.6%) against Rhizoctonia solani and 15 isolates (14.7%) against Sclerotium rolfsii. The results based on 16 rRNA gene sequencing revealed that the PGP bacteria belonged to 22 different species comprising 13 genera. Based on multifunctional properties, nine isolates were further selected to determine the PGP in brinjal and chilli seeds. Of the bacteria tested, the isolate BAN87 showed increased root and shoot length of both the crops followed in plant growth promotion by BAN86 and BAN43. The outcome of this research proves plausible practical applicability of these PGPB for crop production in soils of saline and arid environments. The present research shows diverse plant growth-promoting (PGP) bacteria could be isolated from the active volcano site and suggests that volcano sites represent an ecological niche, which harbours a diverse and hitherto largely uncharacterized microbial population with yet unknown and untapped potential biotechnological applications, for example, plant growth promoters, as evidenced from this study. The outcome of this research may have a practical effect on crop production methodologies in saline and arid environment soils. © 2013 The Society for Applied Microbiology.

Molecular and biochemical characterization of Iranian surfactin-producing Bacillus subtilis isolates and evaluation of their biocontrol potential against Aspergillus flavus and Colletotrichum gloeosporioides.

PubMed

Mohammadipour, Matin; Mousivand, Maryam; Salehi Jouzani, Gholamreza; Abbasalizadeh, Saeed

2009-04-01

The characterization of surfactin-producing Bacillus subtilis isolates collected from different ecological zones of Iran is presented. Characterization was performed using blood agar, PCR, drop-collapse, and reverse-phase high-performance liquid chromatography (HPLC) analyses, and the isolates' biocontrol effects against the aflatoxin-producing agent Aspergillus flavus and the citrus antracnosis agent Colletotrichum gloeosporioides were studied. In total, 290 B. subtilis isolates were isolated from phylosphere and rhizosphere samples collected from fields and gardens of 5 provinces of Iran. Blood agar assays showed that 185 isolates produced different biosurfactants. Isolates containing the sfp gene, coding for surfactin, were detected using the PCR method. It was found that 14 different isolates contained the sfp gene. Drop-collapse assays, which detect isolates with high production of surfactin, showed that 7 isolates produced high levels of surfactin. It was found from HPLC analysis that the isolates containin the sfp gene produced between 55 and 1610 mg of surfactin per litre of broth medium. Four isolates, named BS119m, BS116l, N3dn, and BS113c, produced more than 1000 mg of surfactin per litre of broth. The highest surfactin production level was observed for isolate BS119m (1610 mg/L). The antagonistic potential of the sfp gene-containing isolates was determined using dual culture and chloroform vapour methods. Our bioassay results indicated that isolate BS119m showed high inhibitory effects against A. flavus (100%) and C. gloeosporioides (88%). Furthermore, the effect of purified surfactin on the growth of A. flavus was evaluated. Mycelia growth was considerably reduced with increasing concentration of surfactin, and 36%, 54%, 84%, and 100% inhibitions of mycelia growth were, respectively, observed at 20, 40, 80, and 160 mg/L after 7 days of incubation.

Mycobacterium tuberculosis Genotypes Determined by Spoligotyping to Be Circulating in Colombia between 1999 and 2012 and Their Possible Associations with Transmission and Susceptibility to First-Line Drugs

PubMed Central

Puerto, Gloria; Erazo, Lina; Wintaco, Maira; Castro, Claudia; Ribón, Wellman; Guerrero, Martha Inírida

2015-01-01

Introduction Tuberculosis (TB) remains a primary public health problem worldwide. The number of multidrug-resistant tuberculosis (MDR TB) cases has increased in recent years in Colombia. Knowledge of M. tuberculosis genotypes defined by spoligotyping can help determine the circulation of genotypes that must be controlled to prevent the spread of TB. Objective To describe the genotypes of M. tuberculosis using spoligotyping in resistant and drug-sensitive isolates and their possible associations with susceptibility to first-line drugs. Methods An analytical observational study was conducted that included 741 isolates of M. tuberculosis from patients. The isolates originated from 31 departments and were obtained by systematic surveillance between 1999 and 2012. Results In total 61.94% of the isolates were resistant to 1 or more drugs, and 147 isolates were MDR. In total, 170 genotypes were found in the population structure of Colombian M. tuberculosis isolates. The isolates were mainly represented by four families: LAM (39.9%), Haarlem (19%), Orphan (17%) and T (9%). The SIT42 (LAM 9) was the most common genotype and contained 24.7% of the isolates, followed by the genotypes SIT62 (Haarlem1), SIT53 (T1), and SIT50 (H3). A high clustering of isolates was evident with 79.8% of the isolates classified into 32 groups. The Beijing family was associated with resistant isolates, whereas the Haarlem and T families were associated with sensitive isolates. The Haarlem family was also associated with grouped isolates (p = 0.031). Conclusions A high proportion (approximately 80%) of isolates was found in clusters; these clusters were not associated with resistance to first-line drugs. The Beijing family was associated with drug resistance, whereas the T and Haarlem families were associated with susceptibility in the Colombian isolates studied. PMID:26066494

Population structure and circulating genotypes of drug-sensitive and drug-resistant Mycobacterium tuberculosis clinical isolates in São Paulo state, Brazil.

PubMed

Martins, Maria Conceição; Giampaglia, Carmen M Saraiva; Oliveira, Rosângela S; Simonsen, Vera; Latrilha, Fábio Oliveira; Moniz, Letícia Lisboa; Couvin, David; Rastogi, Nalin; Ferrazoli, Lucilaine

2013-03-01

São Paulo is the most populous Brazilian state and reports the largest number of tuberculosis cases in the country annually (over 18,500). This study included 193 isolates obtained during the 2nd Nationwide Survey on Mycobacterium tuberculosis Drug Resistance that was conducted in São Paulo state and 547 isolates from a laboratory based study of drug resistance that were analyzed by the Mycobacteria Reference Laboratory at the Institute Adolfo Lutz. Both studies were conducted from 2006 to 2008 and sought to determine the genetic diversity and pattern of drug resistance of M. tuberculosis isolates (MTC) circulating in São Paulo. The patterns obtained from the spoligotyping analysis demonstrated that 51/740 (6.9%) of the isolates corresponded to orphan patterns and that 689 (93.1%) of the isolates distributed into 144 shared types, including 119 that matched a preexisting shared type in the SITVIT2 database and 25 that were new isolates. A total of 77/144 patterns corresponded to unique isolates, while the remaining 67 corresponded to clustered patterns (n=612 isolates clustered into groups of 2-84 isolates each). The evolutionarily ancient PGG1 lineages (Beijing, CAS1-DEL, EAI3-IND, and PINI2) were rarely detected in São Paulo and comprised only 13/740, or 1.76%, of the total isolates; all of the remaining 727/740, or 98.24%, of the MTC isolates from São Paulo state were from the recent PGG2/3 evolutionary isolates belonging to the LAM, T, S, X, and Haarlem lineages, i.e., the Euro-American group. This study provides the first overview of circulating genotypes of M. tuberculosis in São Paulo state and demonstrates that the clustered shared types containing seven or more M. tuberculosis isolates that are spread in São Paulo state included both resistant and susceptible isolates. Copyright © 2012 Elsevier B.V. All rights reserved.

Pentamidine is active in vitro against Fusarium species.

PubMed

Lionakis, Michail S; Lewis, Russell E; Samonis, George; Kontoyiannis, Dimitrios P

2003-10-01

Fusariosis is an emerging opportunistic mycosis against which currently used antifungals have limited activity. Here, we investigated the in vitro activities of pentamidine (PNT) against 10 clinical isolates of Fusarium species (five Fusarium solani isolates and five non-F. solani isolates) by using the National Committee for Clinical Laboratory Standards microdilution method in three different media (RPMI, RPMI-2, and a yeast nitrogen base medium), disk diffusion testing, and viability dye staining. PNT had significant activities against all 10 Fusarium isolates. Non-F. solani isolates were more susceptible than F. solani isolates (P < 0.05). Additionally, PNT was fungicidal against all non-F. solani isolates, whereas it had fungistatic effects against four of the five F. solani isolates. PNT also exhibited greater activity against conidial than against hyphal development of the fungus. This fungicidal activity against non-F. solani Fusarium isolates was confirmed microscopically after staining of PNT-treated Fusarium oxysporum hyphae with the fluorescent viability dyes 5,(6)-carboxyfluorescein diacetate (CFDA) and bis-(1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC). The MICs at which 50% of the isolates were inhibited (2 micro g/ml for non-F. solani isolates and 4 micro g/ml for F. solani isolates) and the minimum fungicidal concentration at which 50% of the isolates were killed (8 micro g/ml for non-F. solani isolates) were much lower than the PNT tissue concentrations previously reported in humans using conventional daily intravenous PNT dosing. Finally, PNT was more active against Fusarium isolates in a hypoxic environment of in vitro growth (P < 0.05). This finding may be clinically significant, because Fusarium, an angiotropic mold, causes tissue infarcts with resultant low tissue perfusion. Our findings suggest that PNT may have a role in the management of Fusarium infections. Future in vivo studies are needed to verify these in vitro findings.

In Vitro Activity of Imipenem against Carbapenemase-Positive Enterobacteriaceae Isolates Collected by the SMART Global Surveillance Program from 2008 to 2014

PubMed Central

Karlowsky, James A.; Kazmierczak, Krystyna M.; Badal, Robert E.; Young, Katherine; Motyl, Mary R.; Sahm, Daniel F.

2017-01-01

ABSTRACT The Study for Monitoring Antimicrobial Resistance Trends (SMART) global surveillance program collected 103,960 isolates of Enterobacteriaceae from 2008 to 2014. From this isolate collection, all ertapenem-nonsusceptible isolates (MIC, ≥1 μg/ml; n = 3,428) and 9,371 isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis with an ertapenem-susceptible extended-spectrum-β-lactamase (ESBL)-positive phenotype were assessed for the presence of common carbapenemase genes using a Check-MDR CT101 microarray (Check-Points, Wageningen, the Netherlands) and published multiplex PCR assays. Testing identified 1,493 isolates that harbored a carbapenemase gene (1,485 ertapenem-nonsusceptible isolates and 8 ertapenem-susceptible ESBL-positive isolates) and accounted for 1.4% (1,493/103,960) of all isolates of Enterobacteriaceae. The most frequently identified carbapenemase genes were the KPC (n = 794), OXA-48-like (n = 300), and NDM (n = 290) genes. Carbapenemase genes were most frequently identified in Klebsiella pneumoniae (n = 1,127), Escherichia coli (n = 149), and Enterobacter cloacae (n = 110). Among the carbapenemase-positive isolates, 66.7% (2/3), 37.0% (111/300), 20.0% (8/40), 3.3% (3/92), 2.3% (18/794), and 0% (0/290) of the isolates with genes for GES, OXA-48-like, IMP, VIM, KPC, and NDM, respectively, were susceptible to imipenem (MIC, ≤1 μg/ml). Isolates that tested as susceptible to imipenem were not uncommon among carbapenemase-positive isolates (9.4%, 141/1,493) and most frequently carried OXA-48-like enzymes (78.7%; 111/141); however, overall, these isolates remained rare (0.1%, 141/103,960). The practice of screening clinical isolates of Enterobacteriaceae that test as susceptible to carbapenems in vitro for the presence of carbapenemase genes remains controversial and requires further study. PMID:28298454

In Vitro Activity of Imipenem against Carbapenemase-Positive Enterobacteriaceae Isolates Collected by the SMART Global Surveillance Program from 2008 to 2014.

PubMed

Karlowsky, James A; Lob, Sibylle H; Kazmierczak, Krystyna M; Badal, Robert E; Young, Katherine; Motyl, Mary R; Sahm, Daniel F

2017-06-01

The Study for Monitoring Antimicrobial Resistance Trends (SMART) global surveillance program collected 103,960 isolates of Enterobacteriaceae from 2008 to 2014. From this isolate collection, all ertapenem-nonsusceptible isolates (MIC, ≥1 μg/ml; n = 3,428) and 9,371 isolates of Escherichia coli , Klebsiella pneumoniae , Klebsiella oxytoca , and Proteus mirabilis with an ertapenem-susceptible extended-spectrum-β-lactamase (ESBL)-positive phenotype were assessed for the presence of common carbapenemase genes using a Check-MDR CT101 microarray (Check-Points, Wageningen, the Netherlands) and published multiplex PCR assays. Testing identified 1,493 isolates that harbored a carbapenemase gene (1,485 ertapenem-nonsusceptible isolates and 8 ertapenem-susceptible ESBL-positive isolates) and accounted for 1.4% (1,493/103,960) of all isolates of Enterobacteriaceae The most frequently identified carbapenemase genes were the KPC ( n = 794), OXA-48-like ( n = 300), and NDM ( n = 290) genes. Carbapenemase genes were most frequently identified in Klebsiella pneumoniae ( n = 1,127), Escherichia coli ( n = 149), and Enterobacter cloacae ( n = 110). Among the carbapenemase-positive isolates, 66.7% (2/3), 37.0% (111/300), 20.0% (8/40), 3.3% (3/92), 2.3% (18/794), and 0% (0/290) of the isolates with genes for GES, OXA-48-like, IMP, VIM, KPC, and NDM, respectively, were susceptible to imipenem (MIC, ≤1 μg/ml). Isolates that tested as susceptible to imipenem were not uncommon among carbapenemase-positive isolates (9.4%, 141/1,493) and most frequently carried OXA-48-like enzymes (78.7%; 111/141); however, overall, these isolates remained rare (0.1%, 141/103,960). The practice of screening clinical isolates of Enterobacteriaceae that test as susceptible to carbapenems in vitro for the presence of carbapenemase genes remains controversial and requires further study. Copyright © 2017 American Society for Microbiology.

Characterization of Staphylococcus caprae Clinical Isolates Involved in Human Bone and Joint Infections, Compared with Goat Mastitis Isolates.

PubMed

d'Ersu, J; Aubin, G G; Mercier, P; Nicollet, P; Bémer, P; Corvec, S

2016-01-01

Staphylococcus caprae is an emerging microorganism in human bone and joint infections (BJI). The aim of this study is to describe the features of S. caprae isolates involved in BJI (H for human) compared with those of isolates recovered in goat mastitis (A for animal). Fourteen isolates of each origin were included. Identifications were performed using a Vitek 2 GP ID card, tuf gene sequencing, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) Vitek MS. Molecular typing was carried out using pulsed-field gel electrophoresis (PFGE) and DiversiLab technology. The crystal violet method was used to determine biofilm-forming ability. Virulence factors were searched by PCR. Vitek MS technology provides an accurate identification for the two types of isolates compared to that of gold-standard sequencing (sensitivity, 96.4%), whereas the Vitek 2 GP ID card was more effective for H isolates. Molecular typing methods revealed two distinct lineages corresponding to the origin despite few overlaps: H and A. In our experimental conditions, no significant difference was observed in biofilm production ability between H and A isolates. Nine isolates (5 H isolates and 4 A isolates) behaved as weak producers while one A isolate was a strong producer. Concerning virulence factors, the autolysin atlC and the serine aspartate adhesin (sdrZ) genes were detected in 24 isolates (86%), whereas the lipase gene was always detected, except in one H isolate (96%). The ica operon was present in 23 isolates (82%). Fibrinogen-binding (fbe) or collagen-binding (cna) genes were not detected by using primers designed for Staphylococcus aureus or Staphylococcus epidermidis, even in low stringency conditions. Although S. caprae probably remains underestimated in human infections, further studies are needed to better understand the evolution and the adaptation of this species to its host. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Association of viridans group streptococci from pregnant women with bacterial vaginosis and upper genital tract infection.

PubMed Central

Rabe, L K; Winterscheid, K K; Hillier, S L

1988-01-01

The prevalence and role of viridans group streptococci in the female genital tract have not been well described. In this study of 482 pregnant women, 147 (30%) were culture positive for viridans group streptococci. Of 392 women with predominant Lactobacillus morphotypes by Gram stain (normal), 110 (28%) were colonized with viridans group streptococci, compared with 37 (41%) of 90 women with bacterial vaginosis (BV) (P = 0.02). To determine whether any species were associated with BV, 177 consecutively isolated viridans group streptococci from the vagina were identified to the species level by using the Facklam scheme. The most frequently isolated species from the vagina was Streptococcus intermedius (13%), followed by Streptococcus acidominimus (6%), Streptococcus constellatus (5%), Streptococcus sanguis II (4%), Streptococcus mitis (2%), Streptococcus salivarius (2%), Streptococcus morbillorum (2%), Streptococcus sanguis I (1%), Streptococcus mutans (0.2%), and Streptococcus uberis (0.2%) with an average of 1.2 species per woman. The distribution of the species among women with BV compared with normal women was not significantly different, with the exception of two species which were associated with BV: S. acidominimus (18% versus 3%, P less than 0.001) and S. morbillorum (6% versus 0.7%, P = 0.005). Amniotic fluid and placenta cultures yielded 54 isolates: S. sanguis II (13 isolates), S. acidominimus (9 isolates), S. intermedius (10 isolates), S. constellatus (3 isolates), S. mitis (4 isolates), S. sanguis I (4 isolates), S. morbillorum (5 isolates), S. mutans (2 isolates), S. uberis (1 isolate), mannitol-positive S. intermedius (1 isolate), and 2 isolates which were not classified. The distribution of species isolated from the upper genital tract was not a reflection of the distribution in the lower genital tract. Dextran-producing species of viridans group streptococci may have a greater pathogenic potential in the placenta than the non-dextran-producing species. PMID:2454943

Association of viridans group streptococci from pregnant women with bacterial vaginosis and upper genital tract infection.

PubMed

Rabe, L K; Winterscheid, K K; Hillier, S L

1988-06-01

The prevalence and role of viridans group streptococci in the female genital tract have not been well described. In this study of 482 pregnant women, 147 (30%) were culture positive for viridans group streptococci. Of 392 women with predominant Lactobacillus morphotypes by Gram stain (normal), 110 (28%) were colonized with viridans group streptococci, compared with 37 (41%) of 90 women with bacterial vaginosis (BV) (P = 0.02). To determine whether any species were associated with BV, 177 consecutively isolated viridans group streptococci from the vagina were identified to the species level by using the Facklam scheme. The most frequently isolated species from the vagina was Streptococcus intermedius (13%), followed by Streptococcus acidominimus (6%), Streptococcus constellatus (5%), Streptococcus sanguis II (4%), Streptococcus mitis (2%), Streptococcus salivarius (2%), Streptococcus morbillorum (2%), Streptococcus sanguis I (1%), Streptococcus mutans (0.2%), and Streptococcus uberis (0.2%) with an average of 1.2 species per woman. The distribution of the species among women with BV compared with normal women was not significantly different, with the exception of two species which were associated with BV: S. acidominimus (18% versus 3%, P less than 0.001) and S. morbillorum (6% versus 0.7%, P = 0.005). Amniotic fluid and placenta cultures yielded 54 isolates: S. sanguis II (13 isolates), S. acidominimus (9 isolates), S. intermedius (10 isolates), S. constellatus (3 isolates), S. mitis (4 isolates), S. sanguis I (4 isolates), S. morbillorum (5 isolates), S. mutans (2 isolates), S. uberis (1 isolate), mannitol-positive S. intermedius (1 isolate), and 2 isolates which were not classified. The distribution of species isolated from the upper genital tract was not a reflection of the distribution in the lower genital tract. Dextran-producing species of viridans group streptococci may have a greater pathogenic potential in the placenta than the non-dextran-producing species.

Actinobacteria Associated With Arbuscular Mycorrhizal Funneliformis mosseae Spores, Taxonomic Characterization and Their Beneficial Traits to Plants: Evidence Obtained From Mung Bean (Vigna radiata) and Thai Jasmine Rice (Oryza sativa)

PubMed Central

Lasudee, Krisana; Tokuyama, Shinji; Lumyong, Saisamorn; Pathom-aree, Wasu

2018-01-01

In this study, we report on the isolation of actinobacteria obtained from spores of Funneliformis mosseae and provide evidence for their potential in agricultural uses as plant growth promoters in vitro and in vivo. Actinobacteria were isolated from spores of F. mosseae using the dilution plate technique and media designed for the selective isolation of members of specific actinobacterial taxa. Six strains namely 48, S1, S3, S4, S4-1 and SP, were isolated and identified based on16S rRNA gene sequences. Phylogenetic analysis showed that isolate SP belonged to the genus Pseudonocardia with P. nantongensis KLBMP 1282T as its closest neighbor. The remaining isolates belonged to the genus Streptomyces. Two isolates, 48 and S3 were most closely related to S. thermocarboxydus DSM 44293T. Isolates S4 and S4-1 shared the highest 16S RNA gene similarity with S. pilosus NBRC 127772T. Isolate S1 showed its closest relationship with the type strain of S. spinoverrucosus NBRC14228T. The ability of these isolates to produce indole-3-acetic acid (IAA), siderophores and the ability to solubilize phosphate in vitro were examined. All isolates produced siderophores, four isolates produced IAA and two isolates solubilized inorganic phosphate at varying levels. S. thermocarboxydus isolate S3 showed the highest IAA production with high activities of phosphate solubilization and siderophore production. The inoculation of mung beans (Vigna radiata) with this strain resulted in a significant increase in fresh weight, root length and total length as an effect of IAA production. In an experiment with rice (Oryza sativa), S. thermocarboxydus isolate S3 promoted the growth of rice plants grown in low nutritional soil under induced drought stress. This report supports the view that the inoculation of rice with plant growth promoting actinobacteria mitigates some adverse effects of low nutrient and drought stress on rice. PMID:29942292

CPm gene diversity in field isolates of Citrus tristeza virus from Colombia.

PubMed

Oliveros-Garay, Oscar Arturo; Martinez-Salazar, Natalhie; Torres-Ruiz, Yanneth; Acosta, Orlando

2009-01-01

The nucleotide sequence diversity of the CPm gene from 28 field isolates of Citrus tristeza virus (CTV) was assessed by SSCP and sequence analyses. These isolates showed two major shared haplotypes, which differed in distribution: A1 was the major haplotype in 23 isolates from different geographic regions, whereas R1 was found in isolates from a discrete region. Phylogenetic reconstruction clustered A1 within an independent group, while R1 was grouped with mild isolates T30 from Florida and T385 from Spain. Some isolates contained several minor haplotypes, which were very similar to, and associated with, the major haplotype.

Heterothallic Type of Mating System for Cordyceps cardinalis

PubMed Central

Sung, Gi-Ho; Shrestha, Bhushan; Han, Sang-Kuk; Kim, Soo-Young

2010-01-01

Cordyceps cardinalis successfully produced its fruiting bodies from multi-ascospore isolates. However, subcultures of multi-ascospore isolates could not produce fruiting bodies after few generations. Fruiting body production also differed from sector to sector of the same isolate. Single ascospore isolates were then co-inoculated in combinations of two to observe the fruiting characteristics. Combinations of certain isolates produced perithecial stromata formation, whereas other combinations did not produce any fruiting bodies. These results show that C. cardinalis is a heterothallic fungus, requiring two isolates of opposite mating types for fruiting body production. It was also shown that single ascospore isolates are hermaphrodites. PMID:23956667

Occurrence of efflux mechanism and cephalosporinase variant in a population of Enterobacter aerogenes and Klebsiella pneumoniae isolates producing extended-spectrum beta-lactamases.

PubMed

Tran, Que-Tien; Dupont, Myrielle; Lavigne, Jean-Philippe; Chevalier, Jacqueline; Pagès, Jean-Marie; Sotto, Albert; Davin-Regli, Anne

2009-04-01

We investigated the occurrence of multidrug resistance in 44 Enterobacter aerogenes and Klebsiella pneumoniae clinical isolates. Efflux was involved in resistance in E. aerogenes isolates more frequently than in K. pneumoniae isolates (100 versus 38% of isolates) and was associated with the expression of phenylalanine arginine beta-naphthylamide-susceptible active efflux. AcrA-TolC overproduction in E. aerogenes isolates was noted. An analysis of four E. aerogenes isolates for which cefepime MICs were high revealed no modification in porin expression but a new specific mutation in the AmpC beta-lactamase.

Type 5 and 8 capsular polysaccharides are expressed by Staphylococcus aureus isolates from rabbits, poultry, pigs, and horses.

PubMed Central

Poutrel, B; Sutra, L

1993-01-01

A total of 103 Staphylococcus aureus isolates from rabbits (n = 37), poultry (n = 33), pigs (n = 27), and horses (n = 6) and 14 Staphylococcus intermedius isolates from wild animals were serotyped for capsular polysaccharide types 5 and 8 by an enzyme-linked immunosorbent assay using polyclonal rabbit antibodies. About 98% of the S. aureus isolates were typeable. Type 5 was predominant in the poultry (75.8%) and pig (66.7%) isolates, whereas type 8 was more frequent among the isolates from rabbits (59.5%) and horses (83.3%). By contrast, none of the 14 S. intermedius isolates was typeable. PMID:8432841

Distribution of the ACME-arcA gene among meticillin-resistant Staphylococcus haemolyticus and identification of a novel ccr allotype in ACME-arcA-positive isolates.

PubMed

Pi, Borui; Yu, Meihong; Chen, Yagang; Yu, Yunsong; Li, Lanjuan

2009-06-01

The aim of this study was to investigate the prevalence and characteristics of ACME (arginine catabolic mobile element)-arcA-positive isolates among meticillin-resistant Staphylococcus haemolyticus (MRSH). ACME-arcA, native arcA and SCCmec elements were detected by PCR. Susceptibilities to 10 antimicrobial agents were compared between ACME-arcA-positive and -negative isolates by chi-square test. PFGE was used to investigate the clonal relatedness of ACME-arcA-positive isolates. The phylogenetic relationships of ACME-arcA and native arcA were analysed using the neighbour-joining methods of mega software. A total of 42 (47.7 %) of 88 isolates distributed in 13 PFGE types were positive for the ACME-arcA gene. There were no significant differences in antimicrobial susceptibility between ACME-arcA-positive and -negative isolates. A novel ccr allotype (ccrAB(SHP)) was identified in ACME-arcA-positive isolates. Among 42 ACME-arcA-positive isolates: 8 isolates harboured SCCmec V, 8 isolates harboured class C1 mec complex and ccrAB(SHP); 22 isolates harbouring class C1 mec complex and 4 isolates harbouring class C2 mec complex were negative for all known ccr allotypes. The ACME-arcA-positive isolates were first found in MRSH with high prevalence and clonal diversity, which suggests a mobility of ACME within MRSH. The results from this study revealed that MRSH is likely to be one of the potential reservoirs of ACME for Staphylococcus aureus.

Cariogenic properties of Streptococcus mutans clinical isolates with sortase defects.

PubMed

Lapirattanakul, Jinthana; Takashima, Yukiko; Tantivitayakul, Pornpen; Maudcheingka, Thaniya; Leelataweewud, Pattarawadee; Nakano, Kazuhiko; Matsumoto-Nakano, Michiyo

2017-09-01

In Streptococcus mutans, a Gram-positive pathogen of dental caries, several surface proteins are anchored by the activity of sortase enzyme. Although various reports have shown that constructed S. mutans mutants deficient of sortase as well as laboratory reference strains with a sortase gene mutation have low cariogenic potential, no known studies have investigated clinical isolates with sortase defects. Here, we examined the cariogenic properties of S. mutans clinical isolates with sortase defects as well as caries status in humans harboring such defective isolates. Sortase-defective clinical isolates were evaluated for biofilm formation, sucrose-dependent adhesion, stress-induced dextran-dependent aggregation, acid production, and acid tolerance. Additionally, caries indices of subjects possessing such defective isolates were determined. Our in vitro results indicated that biofilm with a lower quantity was formed by sortase-defective as compared to non-defective isolates. Moreover, impairments of sucrose-dependent adhesion and stress-induced dextran-dependent aggregation were found among the isolates with defects, whereas no alterations were seen in regard to acid production or tolerance. Furthermore, glucan-binding protein C, a surface protein anchored by sortase activity, was predominantly detected in culture supernatants of all sortase-defective S. mutans isolates. Although the sortase-defective isolates showed lower cariogenic potential because of a reduction in some cariogenic properties, deft/DMFT indices revealed that all subjects harboring those isolates had caries experience. Our findings suggest the impairment of cariogenic properties in S. mutans clinical isolates with sortase defects, though the detection of these defective isolates seemed not to imply low caries risk in the subjects harboring them. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phenotypic and genetic characterization of Vibrio cholerae O1 clinical isolates collected through national antimicrobial resistance surveillance network in Nepal.

PubMed

Shakya, Geeta; Kim, Dong Wook; Clemens, John D; Malla, Sarala; Upadhyaya, Bishnu Prasad; Dumre, Shyam Prakash; Shrestha, Sirjana Devi; Adhikari, Shailaja; Sharma, Supriya; Rijal, Nisha; Shrestha, Sanjaya K; Mason, Carl; Kansakar, Palpasa

2012-08-01

Cholera occurs in sporadic cases and outbreaks in Nepal each year. Vibrio cholerae O1 (n = 522) isolated during 2007-2010 from diarrheal patients at 10 different hospital laboratories in Nepal were characterized. Biochemical and serologic identifications showed that all the isolates belonged to serogroup O1, El Tor biotype. Except 72 isolates of Inaba serotype isolated in the year 2007, all the remaining isolates were of Ogawa serotype. All isolates were resistant to nalidixic acid and furazolidone. Resistance to tetracycline, ciprofloxacin, erythromycin and co-trimoxazole were 21, 4, 16 and 90 % respectively. Seventy-seven of these isolates were selected for further characterization for ctxB gene and MLVA typing. Two different variants of classical type cholera toxin were observed. Ogawa strains from 2007 and 2010-Western Nepal outbreak harbored CTX-3 type cholera toxin, whereas Inaba serotypes in 2007 and the remaining Ogawa serotypes in 2008-2010 harbored CTX 3b-type toxin. MLVA analysis showed circulation of four different groups of altered V. cholerae O1 El Tor strains. Two different profiles were seen among 2007 Inaba (9, 3, 6, x, x) and Ogawa (10, 7, 6, x, x) isolates. The MLVA profile of 2008 and 2009 Ogawa isolates were similar to those of Inaba strains of 2007. Isolates from 2010 also showed three different MLVA profiles; profile 9, 3, 6, x, x in 3 isolates, 11, 7, 6, x, x among 2010 Western Nepal outbreak strains and profile 8, 3, 6, x, x among isolates from Butwal and Kathmandu.

Social isolation after spinal cord injury: Indicators from the Longitudinal Aging Study.

PubMed

Newman, Susan D; Li, Chao; Krause, James S

2016-11-01

The purpose of this study was to develop and test a conceptual model of social isolation, incorporating social disconnectedness (objective measures) and perceived isolation (subjective appraisals) in an aging sample of participants with spinal cord injury (SCI). The study used cross-sectional data from 768 participants from the most recent administration of the SCI Longitudinal Aging Study, which was initiated in 1973. Measures included the revised version of the Life Situation Questionnaire, items from the Craig Handicap Assessment Reporting Technique, and the Patient Reported Outcomes Measurement Information System. Indicators of social isolation were combined into scales assessing social disconnectedness and perceived isolation. We tested the hypothesized model of social isolation, including both social disconnectedness and perceived isolation, after SCI using structural equation modeling. Results of structural equation modeling indicated good fit between the hypothesized model and data (root-mean-square error of approximation = 0.073, 90% confidence interval [0.070, 0.075]; comparative fit index = 0.949; Tucker Lewis Index = 0.946). Perceived isolation was significantly related with social disconnectedness (standardized coefficient [r] = .610). Several exogenous factors were significantly related to social disconnectedness and perceived isolation. Older participants were more likely to report lower levels of perceived isolation. Time since injury demonstrated an inverse relationship with both social disconnectedness and perceived isolation. Higher level and severity of injury were associated with higher levels of social disconnectedness. Our study establishes a stable model of social isolation to guide future research exploring the effect of social isolation on health after SCI. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Distribution and Genetic Variability of Fusarium oxysporum Associated with Tomato Diseases in Algeria and a Biocontrol Strategy with Indigenous Trichoderma spp.

PubMed Central

Debbi, Ali; Boureghda, Houda; Monte, Enrique; Hermosa, Rosa

2018-01-01

Fifty fungal isolates were sampled from diseased tomato plants as result of a survey conducted in seven tomato crop areas in Algeria from 2012 to 2015. Morphological criteria and PCR-based identification, using the primers PF02 and PF03, assigned 29 out of 50 isolates to Fusarium oxysporum (Fo). The banding patterns amplified for genes SIX1, SIX3 and SIX4 served to identify races 2 and 3 of Fo f. sp. lycopersici (FOL), and Fo f. sp. radicis lycopersici (FORL) among the Algerian isolates. All FOL isolates showed pathogenicity on the susceptible tomato cv. “Super Marmande,” while nine of out 10 Algerian FORL isolates were pathogenic on tomato cv. “Rio Grande.” Inter simple sequence repeat (ISSR) fingerprints showed high genetic diversity among Algerian Fo isolates. Seventeen Algerian Trichoderma isolates were also obtained and assigned to the species T. asperellum (12 isolates), T. harzianum (four isolates) and T. ghanense (one isolate) based on ITS and tef1α gene sequences. Different in vitro tests identified the antagonistic potential of native Trichoderma isolates against FORL and FOL. Greenhouse biocontrol assays performed on “SM” tomato plants with T. ghanense T8 and T. asperellum T9 and T17, and three Fo isolates showed that isolate T8 performed well against FORL and FOL. This finding was based on an incidence reduction of crown and root rot and Fusarium wilt diseases by 53.1 and 48.3%, respectively. PMID:29515557

Pasteurellaceae isolated from bighorn sheep (Ovis canadensis) from Idaho, Oregon, and Wyoming.

PubMed

Miller, David S; Weiser, Glen C; Ward, Alton C S; Drew, Mark L; Chapman, Phillip L

2012-07-01

To elucidate the species and biovariants of Pasteurellaceae isolated from clinically normal bighorn sheep (Ovis canadensis) or bighorn sheep with evidence of respiratory disease. 675 Pasteurellaceae isolates from 290 free-ranging bighorn sheep in Idaho, Oregon and Wyoming. Nasal and oropharyngeal swab specimens were inoculated onto selective and nonselective blood agar media. Representatives of each colony type were classified via a biovariant scheme. The association of respective β-hemolytic isolates with respiratory disease was evaluated via χ(2) analyses. Bacterial isolates belonged to 4 species: Histophilus somni, Mannheimia haemolytica, Pasteurella multocida, and Bibersteinia (Pasteurella) trehalosi. Within the latter 3 species, 112 subspecies, biotypes, and biovariants were identified. Bibersteinia trehalosi 2 and B trehalosi 2B constituted 345 of 675 (51%) isolates. Most (597/618 [97%]) isolates from adult sheep were from clinically normal animals, whereas most (47/57 [82%]) isolates from lambs were from animals with evidence of respiratory disease. Twenty-two Pasteurellaceae biovariants were isolated from sheep with respiratory disease; 17 of these biovariants were also isolated from clinically normal sheep. The ability of isolates to cause β-hemolysis on blood agar was associated with respiratory disease in adult bighorn sheep (OR, 2.59; 95% confidence interval, 1.10 to 6.07). Bighorn lambs appeared more susceptible to respiratory disease caused by Pasteurellaceae than did adult sheep. β-Hemolytic Pasteurellaceae isolates were more likely to be associated with respiratory disease than were non-β-hemolytic isolates in adult sheep. Identification of Pasteurellaceae with the greatest pathogenic potential will require studies to estimate the risk of disease from specific biovariants.

Seismic response evaluation of base-isolated reinforced concrete buildings under bidirectional excitation

NASA Astrophysics Data System (ADS)

Bhagat, Satish; Wijeyewickrema, Anil C.

2017-04-01

This paper reports on an investigation of the seismic response of base-isolated reinforced concrete buildings, which considers various isolation system parameters under bidirectional near-fault and far-fault motions. Three-dimensional models of 4-, 8-, and 12-story base-isolated buildings with nonlinear effects in the isolation system and the superstructure are investigated, and nonlinear response history analysis is carried out. The bounding values of isolation system properties that incorporate the aging effect of isolators are also taken into account, as is the current state of practice in the design and analysis of base-isolated buildings. The response indicators of the buildings are studied for near-fault and far-fault motions weight-scaled to represent the design earthquake (DE) level and the risk-targeted maximum considered earthquake (MCER) level. Results of the nonlinear response history analyses indicate no structural damage under DE-level motions for near-fault and far-fault motions and for MCER-level far-fault motions, whereas minor structural damage is observed under MCER-level near-fault motions. Results of the base-isolated buildings are compared with their fixed-base counterparts. Significant reduction of the superstructure response of the 12-story base-isolated building compared to the fixed-base condition indicates that base isolation can be effectively used in taller buildings to enhance performance. Additionally, the applicability of a rigid superstructure to predict the isolator displacement demand is also investigated. It is found that the isolator displacements can be estimated accurately using a rigid body model for the superstructure for the buildings considered.

Antimicrobial Susceptibility and Clonality of Clinical Ureaplasma Isolates in the United States.

PubMed

Fernández, Javier; Karau, Melissa J; Cunningham, Scott A; Greenwood-Quaintance, Kerryl E; Patel, Robin

2016-08-01

Ureaplasma urealyticum and Ureaplasma parvum are pathogens involved in urogenital tract and intrauterine infections and also in systemic diseases in newborns and immunosuppressed patients. There is limited information on the antimicrobial susceptibility and clonality of these species. In this study, we report the susceptibility of 250 contemporary isolates of Ureaplasma (202 U. parvum and 48 U. urealyticum isolates) recovered at Mayo Clinic, Rochester, MN. MICs of doxycycline, azithromycin, ciprofloxacin, tetracycline, erythromycin, and levofloxacin were determined by broth microdilution, with MICS of the last three interpreted according to CLSI guidelines. Levofloxacin resistance was found in 6.4% and 5.2% of U. parvum and U. urealyticum isolates, respectively, while 27.2% and 68.8% of isolates, respectively, showed ciprofloxacin MICs of ≥4 μg/ml. The resistance mechanism of levofloxacin-resistant isolates was due to mutations in parC, with the Ser83Leu substitution being most frequent, followed by Glu87Lys. No macrolide resistance was found among the 250 isolates studied; a single U. parvum isolate was tetracycline resistant. tet(M) was found in 10 U. parvum isolates, including the single tetracycline-resistant isolate, as well as in 9 isolates which had low tetracycline and doxycycline MICs. Multilocus sequence typing (MLST) performed on a selection of 46 isolates showed high diversity within the clinical Ureaplasma isolates studied, regardless of antimicrobial susceptibility. The present work extends previous knowledge regarding susceptibility to antimicrobial agents, resistance mechanisms, and clonality of Ureaplasma species in the United States. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Identification of Major Sequence Types among Multidrug-Resistant Staphylococcus epidermidis Strains Isolated from Infected Eyes and Healthy Conjunctiva

PubMed Central

Jena, Smrutiti; Panda, Sasmita; Nayak, Kinshuk C.; Singh, Durg V.

2017-01-01

We examined the presence of virulence and antibiotic resistance genes, SCCmec types and determined the genomic diversity among ocular S. epidermidis isolates (patients-23, healthy controls-29). PCR determined the presence of antibiotic resistance genes, virulence genes and SCCmec types among all isolates. MLST and PFGE determined the genomic relatedness among them. All isolates of S. epidermidis showed resistance to at least one class of antibiotics of which 48 isolates were multidrug resistant and carried ARGs. Thirty-five isolates were methicillin resistant and carried mecA gene. Majority of the isolates were resistant to fluoroquinolones and showed mutation in gyrA, parC, and parE genes, however, few isolates showed additional novel mutations in parC gene. Of the MRSE strains, 17 strains carried SCCmec type IV, four type V, two type II, and two UT4. Seven strains carried novel combination of ccr complex and SCCmercury element, not reported earlier. All the S. epidermidis strains harbored icaA and icaD genes, 47 carried ACME operon, and 50 contained IS256. A noteworthy finding was the presence of ST179 among 43% of infected eye isolates an observation rarely reported among S. epidermidis. PFGE and MLST analysis showed genomic diversity among them. Statistical analysis suggests that few healthy conjunctiva isolates had characteristics similar to infected eye isolates. S. epidermidis strains carrying mecA gene are multidrug resistant, virulent and diverse irrespective of sources of isolation. IS256 cannot be used as marker to differentiate isolates of infected eye from healthy conjunctiva. PMID:28824564

Population Relationship of Vibrio parahaemolyticus Isolates Derived from Aquaculture Ponds, a Seafood Market, Restaurants, and Clinical Samples.

PubMed

Gao, Lei; Deng, Yi Qin; Chen, Chang; Ke, Chang Wen; Li, Bo Sheng; Long, Yun Ying; Liu, Zhu Hong; Wei, Lu

2016-06-01

To study the relationship between environmental and clinical populations of Vibrio parahaemolyticus, we collected in total 86 isolates from Southern China during one and a half years. Sixty-eight isolates were recovered from aquaculture ponds, a seafood market, and restaurants, and 18 isolates were recovered from clinical samples. Virulence gene analysis revealed that 25 isolates (14 clinical and 11 environmental) tested positive for tdh, but only 4 carried trh. Interestingly, none of the tdh(+) environmental isolates was recovered from ponds. Both environmental and clinical tdh(+) isolates, except for one clinical isolate, harbor type III secretion system 2α (T3SS2α) and T3SS2β-related genes, including vopB2α, which was previously suggested to be absent from environmental strains. More than 70% of clinical isolates carried the pandemic marker of new toxRS (GS-PCR(+)), which was not present in the environmental isolates. Pulsed-field gel electrophoresis and multilocus sequence typing analysis showed a high degree of genetic diversity within the environmental isolates. In contrast, the clinical population formed a tight cluster that differed from the environmental isolates. These findings suggest that the pandemic strains of V. parahaemolyticus may not directly originate from marine animals. Rather the environments where they are maintained could serve as reservoirs for toxigenic, but not pandemic strains. These environments provide an ideal place for generation of new toxigenic strains through DNA exchange, which was revealed by extensive recombination events in recA sequences of the environmental isolates.

Rapid Identification of Vancomycin Resistant Enterococcus Faecalis Clinical Isolates using a Sugar Fermentation Method

PubMed Central

Raeisi, Javad; Saifi, Mahnaz; Pourshafie, Mohammad Reza; Habibi, Mehri; Mohajerani, Hamid Reza; Akbari, Neda

2017-01-01

Introduction Vancomycin Resistant Enterococci (VRE) can be found all over the world. Thus, rapid detection of the isolates could be of high importance in the treatment or prevention of the associated disease. Aim To measure the turanose fermentation in Enterococcus faecalis clinical isolates for rapid differentiation of VRE and Vancomycin-Susceptible E. faecalis (VSE) isolates. Materials and Methods Forty E. faecalis samples were isolated from 200 clinical samples in Tehran Medical Center, Iran, from October 2012 to December 2012. These isolates were detected according to the standard microbial and biochemical tests. Detection of VRE isolates was originally performed by disk diffusion using 1 μg vancomycin disk, followed by Polymerase Chain Reaction (PCR) amplification of the vanA gene. Finally, the turanose consumption in 1%, 0.7% and 0.5% dilutions was detected by a phenotypic method. Results Among the 40 E. faecalis isolates, 20 vancomycin-susceptible and 20 vancomycin-resistant E. faecalis were isolated according to the disk diffusion and PCR of the vanA gene. There was a considerable difference between VRE and VSE isolates in 0.7% dilution of turanose. However, there was no significant difference between VRE and VSE in 1% and 0.5% dilutions of turanose. Conclusion Since detection of VRE isolates is of high importance, especially in nosocomial infections, phenotypic methods may be highly useful for this purpose. In conclusion, our data indicate that VRE isolated from clinical samples could be distinguished from VSE isolates by turanose fermentation at dilution 0.7%. PMID:28511382

Epidemiology, Clinical Characteristics, and Antimicrobial Susceptibility Profiles of Human Clinical Isolates of Staphylococcus intermedius Group.

PubMed

Yarbrough, Melanie L; Lainhart, William; Burnham, C A

2018-03-01

The veterinary pathogens in the Staphylococcus intermedius group (SIG) are increasingly recognized as causes of human infection. Shared features between SIG and Staphylococcus aureus may result in the misidentification of SIG in human clinical cultures. This study examined the clinical and microbiological characteristics of isolates recovered at a tertiary-care academic medical center. From 2013 to 2015, 81 SIG isolates were recovered from 62 patients. Patients were commonly ≥50 years old, diabetic, and/or immunocompromised. Documentation of dog exposure in the electronic medical record was not common. Of the 81 SIG isolates, common sites of isolation included 37 (46%) isolates from wound cultures and 17 (21%) isolates from respiratory specimens. Although less common, 10 (12%) bloodstream infections were documented in 7 unique patients. The majority of SIG (65%) isolates were obtained from polymicrobial cultures. In comparison to S. aureus isolates from the same time period, significant differences were noted in proportion of SIG isolates that were susceptible to doxycycline (74% versus 97%, respectively; P < 0.001), trimethoprim-sulfamethoxazole (65% versus 97%, respectively; P < 0.001), and ciprofloxacin (78% versus 59%, respectively; P < 0.01). Methicillin resistance (MR) was detected in 12 (15%) of 81 SIG isolates. All MR isolates detected by an oxacillin disk diffusion test would have been misclassified as methicillin susceptible using a cefoxitin disk diffusion test. Thus, SIG is recovered from human clinical specimens, and distinction of SIG from S. aureus is critical for the accurate characterization of MR status in these isolates. Copyright © 2018 American Society for Microbiology.

Genetic basis for loss of immuno-reactive O-chain in Salmonella enterica serovar Enteritidis veterinary isolates.

PubMed

Szabo, Istvan; Grafe, Marianne; Kemper, Nicole; Junker, Ernst; Malorny, Burkhard

2017-05-01

Fifty-two rough Salmonella enterica serovar Enteritidis (S. Enteritidis) isolates from broilers and the environment were characterized for their serological and genotypic properties. Under routine diagnostic serotyping methods such isolates lack the immuno-reactivity of the O-chain of the lipopolysaccharide (LPS), and are referred to as non-typeable. Using a modified slide agglutination method, the isolates could be differentiated into three different serological variants. Twenty-six isolates (50%) were defined as semi-rough, nineteen isolates (37%) as deep-rough, four isolates (8%) as rough and three isolates could not be assigned. Genetically, all semi-rough isolates lacked the wzyB gene encoding the O-antigen polymerase. Two isolates carried a frameshift mutation in wzyB. In 15 of 23 cases deep-rough or rough isolates had a single point mutation, a single - or double-nucleotide insert or deletion in the wbaP gene. The mutational changes lead to expression of truncated (premature) protein, resulting in the loss of the immuno-reactive O-chain. Both rough and smooth S. Enteritidis isolates showed identical or highly similar XbaI-PFGE profiles. Our results indicate that the loss of a functional LPS in S. Enteritidis isolates is caused by a variety of different mutation events within the wzyB (semi-rough) or the wbaP (deep-rough) gene and is not a result of a vertical spread of a specific S. Enteritidis subtype. The defect of the LPS may be a common evolutionary mechanism through which host defence can be escaped. Copyright © 2017. Published by Elsevier B.V.

Seagulls of the Berlengas natural reserve of Portugal as carriers of fecal Escherichia coli harboring CTX-M and TEM extended-spectrum beta-lactamases.

PubMed

Poeta, Patricia; Radhouani, Hajer; Igrejas, Gilberto; Gonçalves, Alexandre; Carvalho, Carlos; Rodrigues, Jorge; Vinué, Laura; Somalo, Sergio; Torres, Carmen

2008-12-01

Escherichia coli isolates containing the following extended-spectrum beta-lactamases have been detected in 11 of 57 fecal samples (19.3%) in Berlengas Island seagulls: TEM-52 (eight isolates), CTX-M-1 (one isolate), CTX-M-14a (one isolate), and CTX-M-32 (one isolate). Most of the extended-spectrum beta-lactamase-positive isolates harbored class 1 or class 2 integrons, which included different antibiotic resistance gene cassettes.

Seagulls of the Berlengas Natural Reserve of Portugal as Carriers of Fecal Escherichia coli Harboring CTX-M and TEM Extended-Spectrum Beta-Lactamases▿

PubMed Central

Poeta, Patricia; Radhouani, Hajer; Igrejas, Gilberto; Gonçalves, Alexandre; Carvalho, Carlos; Rodrigues, Jorge; Vinué, Laura; Somalo, Sergio; Torres, Carmen

2008-01-01

Escherichia coli isolates containing the following extended-spectrum beta-lactamases have been detected in 11 of 57 fecal samples (19.3%) in Berlengas Island seagulls: TEM-52 (eight isolates), CTX-M-1 (one isolate), CTX-M-14a (one isolate), and CTX-M-32 (one isolate). Most of the extended-spectrum beta-lactamase-positive isolates harbored class 1 or class 2 integrons, which included different antibiotic resistance gene cassettes. PMID:18835997

Genetic disorders of the anterior pituitary gland.

PubMed

Teller, W M

1985-01-01

This survey deals with disorders caused by genetically disturbed function of the anterior pituitary gland. Genetic Dwarfism may be caused by isolated growth hormone deficiency (IGHD) or panpituitary diseases, such as congenital absence of the pituitary or familial panhypopituitarism. Genetic disturbances of isolated pituitary hormone secretion without dwarfism may occur as isolated gonadotropin deficiency (IGD), isolated luteinizing hormone deficiency ("fertile eunuch"), Kallmann syndrome (olfactogenital dysplasia), isolated thyrotropin deficiency (ITD) and isolated corticotropin deficiency (ICD). Pituitary dysfunction may also be associated with other genetic disease entities.

Antibacterial Activity of the Isolation Ethyl Acetate-Soluble Extract Noni Fruit (Morindra citrifolia L.) against Meat Bacterial Decay

NASA Astrophysics Data System (ADS)

Nugraheni, E. R.; Nurrakhman, M. B. E.; Munawaroh, H.; Saputri, L.

2017-02-01

Noni (Morindra citrifolia L.) is native to Indonesia which have medicinal properties. One of them as an antibacterial. This study aims to determine the antibacterial activity of isolates from the ethanol extract noni fruit to bacterial decay meat is Bacillus licheniformis, Klebsiella pneumonia, Bacillus alvei, Acinetobacter calcoaceticus, and Staphylococcus saprophyticus. The extraction process using the maceration method, and then made a partition by centrifugation ethyl acetate. Soluble part partition showed bacterial growth inhibition activity of the strong to very strong. Furthermore, the ethyl acetate soluble partition on preparative thin layer chromatography produced 5 isolates. Isolates obtained antibacterial activity test performed with a concentration of 20% and 30%. The results of antibacterial test against bacteria test isolates, showing isolates A can not inhibit the growth of bacteria, isolates B and C have medium activity and strong, isolates D and E isolates have activity against bacteria that were tested. MIC and MBC test results showed that the isolates B gives an inhibitory effect (bacteriostatic) against all bacteria. Content analysis of compounds by TLC using the reagents cerium (IV) sulfate indicates a phenol group. Isolates B contains a major compound which can be used as an antibacterial candidate in food preservation replace chemical preservatives.

Assessing Social Isolation: Pilot Testing Different Methods.

PubMed

Taylor, Harry Owen; Herbers, Stephanie; Talisman, Samuel; Morrow-Howell, Nancy

2016-04-01

Social isolation is a significant public health problem among many older adults; however, most of the empirical knowledge about isolation derives from community-based samples. There has been less attention given to isolation in senior housing communities. The objectives of this pilot study were to test two methods to identify socially isolated residents in low-income senior housing and compare findings about the extent of isolation from these two methods. The first method, self-report by residents, included 47 out of 135 residents who completed in-person interviews. To determine self-report isolation, residents completed the Lubben Social Network Scale 6 (LSNS-6). The second method involved a staff member who reported the extent of isolation on all 135 residents via an online survey. Results indicated that 26% of residents who were interviewed were deemed socially isolated by the LSNS-6. Staff members rated 12% of residents as having some or a lot of isolation. In comparing the two methods, staff members rated 2% of interviewed residents as having a lot of isolation. The combination of self-report and staff report could be more informative than just self-report alone, particularly when participation rates are low. However, researchers should be aware of the potential discrepancy between these two methods.

Effects of the mode of re-socialization after juvenile social isolation on medial prefrontal cortex myelination and function.

PubMed

Makinodan, Manabu; Ikawa, Daisuke; Yamamuro, Kazuhiko; Yamashita, Yasunori; Toritsuka, Michihiro; Kimoto, Sohei; Yamauchi, Takahira; Okumura, Kazuki; Komori, Takashi; Fukami, Shin-Ichi; Yoshino, Hiroki; Kanba, Shigenobu; Wanaka, Akio; Kishimoto, Toshifumi

2017-07-14

Social isolation is an important factor in the development of psychiatric disorders. It is necessary to develop an effective psychological treatment, such as cognitive rehabilitation, for children who have already suffered from social isolation, such as neglect and social rejection. We used socially isolated mice to validate whether elaborate re-socialization after juvenile social isolation can restore hypomyelination in the medial prefrontal cortex (mPFC) and the attendant functions manifested in socially isolated mice. While mice who underwent re-socialization with socially isolated mice after juvenile social isolation (Re-IS mice) demonstrated less mPFC activity during exposure to a strange mouse, as well as thinner myelin in the mPFC than controls, mice who underwent re-socialization with socially housed mice after juvenile social isolation (Re-SH mice) caught up with the controls in terms of most mPFC functions, as well as myelination. Moreover, social interaction of Re-IS mice was reduced as compared to controls, but Re-SH mice showed an amount of social interaction comparable to that of controls. These results suggest that the mode of re-socialization after juvenile social isolation has significant effects on myelination in the mPFC and the attendant functions in mice, indicating the importance of appropriate psychosocial intervention after social isolation.

Isolation, in vitro culture, ultrastructure study, and characterization by lectin-agglutination tests of Phytomonas isolated from tomatoes (Lycopersicon esculentum) and cherimoyas (Anona cherimolia) in southeastern Spain.

PubMed

Sanchez-Moreno, M; Fernandez-Becerra, C; Mascaro, C; Rosales, M J; Dollet, M; Osuna, A

1995-01-01

Plants of Lycopersicon esculentum (grown in greenhouses) and Anona cherimolia cultivated in southeastern Spain were examined for the presence of trypanosomatid flagellates. Kinetoplastid protozoa were found in the fruits but not in the phloem or other plant tissues. Parasites were detected from the onset of fruiting. Isolates were detected from the onset of fruiting. Isolates were adapted to in vitro culturing in monophase media. The form and the structural organization was studied by scanning and transmission electron microscopy. The parasites showed an ultrastructural pattern similar to that of other species of the genus Phytomonas. In tomatoes experimentally inoculated with flagellates cultivated in vitro, we observed that the parasites did not lose their infectious capacity. Three strains of trypanosomatids of the genus Phytomonas, isolated from different species of Euphorbia (E. characias and E. hyssopifolia) and from Cocos nucifera, were compared with our isolates by lectin-agglutination tests. Our isolates were different from the two strains isolated from Euphorbia, but with this technique we could not differentiate our isolates from those of the coconut, nor could we differentiate between the isolates, their ultrastructural similarity together with their similar behavior in the lectin-agglutination test suggesting that these isolates have a common origin.

Ground Isolation Circuit for Isolating a Transmission Line from Ground Interference

NASA Technical Reports Server (NTRS)

Davidson, Craig A. (Inventor)

1996-01-01

This invention relates generally to a system for isolating ground interference from a transmission line, e.g., a ground isolation circuit for isolating a wideband transmission signal (such as a video signal) from ground by modulating the base signal on a carrier signal to permit the transmission signal to be isolated. In one embodiment, the circuit includes a pair of matched mixer circuits, each of which receives a carrier signal from the same oscillator circuit. The first mixer circuit also receives the baseband signal input, after appropriate conditioning, and modulates the baseband signal onto the carrier signal. In a preferred embodiment the carrier signal has a predetermined frequency which is at least two times the frequency of the baseband signal. The modulated signal (which can comprise an rf signal) is transmitted via an rf transmission line to the second mixer, which demodulates the rf signal to recover the baseband signal. Each port of the mixer connects to an isolation transformer to ensure isolation from ground interference. The circuit is considered to be of commercial value in that it can provide isolation between transmitting and receiving circuits, e.g., ground isolation for television circuits or high frequency transmitters, without the need for video transformers or optical isolators, thereby reducing the complexity, power consumption, and weight of the system.

Clinical and molecular epidemiology of hospital Enterococcus faecalis isolates in eastern France.

PubMed

Mulin, Blandine; Bailly, Pascale; Thouverez, Michelle; Cailleaux, Vincent; Cornette, Christian; Dupont, Marie-Jeanne; Talon, Daniel

1999-03-01

OBJECTIVE: To report on the occurrence of Enterococcus faecalis hospital isolates obtained during 1 year in hospitals in the Franche-Comté region of France. METHODS: Clinical isolates of E. faecalis of different antibiotic susceptibility phenotypes from hospitalized patients were characterized by pulsed-field gel electrophoresis. Patients with positive cultures were investigated by three case-control studies to identify risk factors for colonization/infection. RESULTS: The crude incidence of colonization/infection was 2.37%, and 4-day and 7-day colonization rates after admission were 10.0% and 6.36%, respectively. The rates of high-level resistance to kanamycin (HLKR) and to gentamicin (HLGR) were 47.1% and 7.1%, respectively. No isolate was resistant to glycopeptides or produced beta-lactamase. The 209 hospital isolates obtained during the study yielded 98 major DNA patterns, of which two were major epidemic patterns including HLKR isolates. No single factor was significantly associated with colonization/infection by HLKR isolates. The length of hospitalization before isolation was associated with colonization by HLGR isolates. CONCLUSIONS: The isolation frequency of E. faecalis strains with acquired resistance to aminoglycoside antibiotics, and the wide dissemination of resistant strains with characteristics that allow them to persist and spread, argue for further large prospective surveys of clinical isolates of E. faecalis in hospitals.

Vibration isolation using six degree-of-freedom quasi-zero stiffness magnetic levitation

NASA Astrophysics Data System (ADS)

Zhu, Tao; Cazzolato, Benjamin; Robertson, William S. P.; Zander, Anthony

2015-12-01

In laboratories and high-tech manufacturing applications, passive vibration isolators are often used to isolate vibration sensitive equipment from ground-borne vibrations. However, in traditional passive isolation devices, where the payload weight is supported by elastic structures with finite stiffness, a design trade-off between the load capacity and the vibration isolation performance is unavoidable. Low stiffness springs are often required to achieve vibration isolation, whilst high stiffness is desired for supporting payload weight. In this paper, a novel design of a six degree of freedom (six-dof) vibration isolator is presented, as well as the control algorithms necessary for stabilising the passively unstable maglev system. The system applies magnetic levitation as the payload support mechanism, which realises inherent quasi-zero stiffness levitation in the vertical direction, and zero stiffness in the other five dofs. While providing near zero stiffness in multiple dofs, the design is also able to generate static magnetic forces to support the payload weight. This negates the trade-off between load capacity and vibration isolation that often exists in traditional isolator designs. The paper firstly presents the novel design concept of the isolator and associated theories, followed by the mechanical and control system designs. Experimental results are then presented to demonstrate the vibration isolation performance of the proposed system in all six directions.

Determination of staphylococcal exotoxins, SCCmec types, and genetic relatedness of Staphylococcus intermedius group isolates from veterinary staff, companion animals, and hospital environments in Korea

PubMed Central

Youn, Jung-Ho; Ahn, Kuk Ju; Lim, Suk-Kyung

2011-01-01

The Staphylococcus (S.) intermedius group (SIG) has been a main research subject in recent years. S. pseudintermedius causes pyoderma and otitis in companion animals as well as foodborne diseases. To prevent SIG-associated infection and disease outbreaks, identification of both staphylococcal exotoxins and staphylococcal cassette chromosome mec (SCCmec) types among SIG isolates may be helpful. In this study, it was found that a single isolate (one out of 178 SIG isolates examined) harbored the canine enterotoxin SEC gene. However, the S. intermedius exfoliative toxin gene was found in 166 SIG isolates although the S. aureus-derived exfoliative toxin genes, such as eta, etb and etd, were not detected. SCCmec typing resulted in classifying one isolate as SCCmec type IV, 41 isolates as type V (including three S. intermedius isolates), and 10 isolates as non-classifiable. Genetic relatedness of all S. pseudintermedius isolates recovered from veterinary staff, companion animals, and hospital environments was determined by pulsed-field gel electrophoresis. Strains having the same band patterns were detected in S. pseudintermedius isolates collected at 13 and 18 months, suggesting possible colonization and/or expansion of a specific S. pseudintermedius strain in a veterinary hospital. PMID:21897094

Determination of staphylococcal exotoxins, SCCmec types, and genetic relatedness of Staphylococcus intermedius group isolates from veterinary staff, companion animals, and hospital environments in Korea.

PubMed

Youn, Jung-Ho; Koo, Hye Cheong; Ahn, Kuk Ju; Lim, Suk-Kyung; Park, Yong Ho

2011-09-01

The Staphylococcus (S.) intermedius group (SIG) has been a main research subject in recent years. S. pseudintermedius causes pyoderma and otitis in companion animals as well as foodborne diseases. To prevent SIG-associated infection and disease outbreaks, identification of both staphylococcal exotoxins and staphylococcal cassette chromosome mec (SCCmec) types among SIG isolates may be helpful. In this study, it was found that a single isolate (one out of 178 SIG isolates examined) harbored the canine enterotoxin SEC gene. However, the S. intermedius exfoliative toxin gene was found in 166 SIG isolates although the S. aureus-derived exfoliative toxin genes, such as eta, etb and etd, were not detected. SCCmec typing resulted in classifying one isolate as SCCmec type IV, 41 isolates as type V (including three S. intermedius isolates), and 10 isolates as non-classifiable. Genetic relatedness of all S. pseudintermedius isolates recovered from veterinary staff, companion animals, and hospital environments was determined by pulsed-field gel electrophoresis. Strains having the same band patterns were detected in S. pseudintermedius isolates collected at 13 and 18 months, suggesting possible colonization and/or expansion of a specific S. pseudintermedius strain in a veterinary hospital.

In vitro interaction of actinomycetes isolates with Aspergillus flavus: impact on aflatoxins B1 and B2 production.

PubMed

Verheecke, C; Liboz, T; Darriet, M; Sabaou, N; Mathieu, F

2014-06-01

This work aimed to study the interaction between Actinomycetal isolates and Aspergillus flavus to promote mutual antagonism in contact. Thirty-seven soilborn Streptomyces spp. isolates were chosen as potential candidates. After a 10-day in vitro co-incubation period, 27 isolates respond to the criteria, that is, mutual antagonism in contact. Further aflatoxins B1 and B2 analysis revealed that those 27 isolates reduced aflatoxin B1 residual concentration from 38·6 to 4·4%, depending on the isolate. We selected 12 isolates and tested their capacity to reduce AFB1 in pure culture to start identifying the mechanisms involved in its reduction. AFB1 was reduced by eight isolates. The remaining AFB1 concentration varied between 82·2 and 15·6%. These findings led us to suggest that these eight isolates could be used as biocontrol agents against AFB1 and B2 with low risk of impacting the natural microbial equilibrium. Interaction between Aspergillus flavus and Actinomycetes isolates was conducted in vitro. Actinomycetes isolates having a mutual antagonism in contact with A. flavus were chosen for further aflatoxins production study. This is a new approach based to develop biocontrol against aflatoxins accumulation in maize while respecting natural microbial equilibrium. © 2014 The Society for Applied Microbiology.

The complete genome sequence of a south Indian isolate of Rice tungro spherical virus reveals evidence of genetic recombination between distinct isolates.

PubMed

Sailaja, B; Anjum, Najreen; Patil, Yogesh K; Agarwal, Surekha; Malathi, P; Krishnaveni, D; Balachandran, S M; Viraktamath, B C; Mangrauthia, Satendra K

2013-12-01

In this study, complete genome of a south Indian isolate of Rice tungro spherical virus (RTSV) from Andhra Pradesh (AP) was sequenced, and the predicted amino acid sequence was analysed. The RTSV RNA genome consists of 12,171 nt without the poly(A) tail, encoding a putative typical polyprotein of 3,470 amino acids. Furthermore, cleavage sites and sequence motifs of the polyprotein were predicted. Multiple alignment with other RTSV isolates showed a nucleotide sequence identity of 95% to east Indian isolates and 90% to Philippines isolates. A phylogenetic tree based on complete genome sequence showed that Indian isolates clustered together, while Vt6 and PhilA isolates of Philippines formed two separate clusters. Twelve recombination events were detected in RNA genome of RTSV using the Recombination Detection Program version 3. Recombination analysis suggested significant role of 5' end and central region of genome in virus evolution. Further, AP and Odisha isolates appeared as important RTSV isolates involved in diversification of this virus in India through recombination phenomenon. The new addition of complete genome of first south Indian isolate provided an opportunity to establish the molecular evolution of RTSV through recombination analysis and phylogenetic relationship.

Molecular diversity of serial Cryptococcus neoformans isolates from AIDS patients in the city of São Paulo, Brazil.

PubMed

Martins, Marilena A; Pappalardo, Mara C S M; Melhem, Márcia S C; Pereira-Chioccola, Vera L

2007-11-01

Despite highly active anti-retroviral therapy, cryptococcal meningoencephalitis is the second most prevalent neurological disease in Brazilian AIDS patients, being frequently a defining condition with several episodes. As knowledge of Cryptococcus neoformans isolates in the same episode is critical for understanding why some patients develop several episodes, we investigated the genotype characteristics of C. neoformans isolates in two different situations. By pulsed field gel electrophoresis and random amplified polymorphic DNA analysis, 54 isolates from 12 patients with AIDS and cryptococcosis were analyzed. Group 1 comprised 39 isolates from nine patients with a single episode and hospitalization. Group 2 comprised 15 isolates from three patients with two episodes and hospitalizations. Except for three patients from group 1 probably infected with a single C. neoformans isolate, the other nine patients probably were infected with multiple isolates selected in different collection periods, or the infecting isolate might have underwent mutation to adapt and survive the host immune system and/or the antifungal therapy. However, the three patients from group 2 presented genetic diversity among isolates collected in both hospitalizations, possibly having hosted the initial isolate in both periods. These data, emphasize that Cryptococcus diversity in infection can contribute to strategies of treatment and prevention of cryptococcosis.

The Helicobacter pylori L-form: formation and isolation in the human bile cultures in vitro and in the gallbladders of patients with biliary diseases.

PubMed

Wang, Dan N; Ding, Wen J; Pan, Yao Z; Tang, Ke L; Wang, Tao; She, Xiao L; Wang, He

2015-04-01

The Helicobacter pylori is considered the important causative agent causing biliary diseases, but the H. pylori can be isolated from very few gallbladder specimens with diseases. We studied the formation of H. pylori L-forms in bile in vitro and isolated the H. pylori L-forms from gallbladder of patients with biliary diseases. We inoculated the H. pylori into the human bile to induce the L-form in vitro. The gallbladder specimens were collected from patients with biliary diseases to isolate the bacterial L-forms by the nonhigh osmotic isolation technique, and the H. pylori L-forms in the L-form isolates were identified by the gene assay for the H. pylori-specific genes 16S rRNA and UreA. The H. Pylori cannot be isolated from the bile-induced cultures, but the H. pylori L-form can be isolated from the H. pylori-negative bile-induced cultures. The L-form isolates of bile-induced cultures showed a positive reaction of the H. pylori-specific genes by PCR, and the coincidence ratio of the nucleotide sequences between the L-forms and the H. pylori is 99%. The isolation rate of bacteria L-form is 93.2% in the gallbladder specimens with bacteria-negative isolation culture by the nonhigh osmotic isolation technique, and the positive rate of the H. pylori-specific genes in the L-form isolates is 7.1% in the bacterial L-form-positive isolation cultures by the PCR. H. pylori can be rapidly induced into the L-form in the human bile; the L-form, as the latent bacteria, can live in the host gallbladder for a long times, and they made the host became a latent carrier of the H. pylori L-form. The H. pylori L-form can be isolated by the nonhigh osmotic isolation technique, and the variant can be identified by the gene assay for the H. pylori-specific genes 16S rRNA and reA. © 2014 John Wiley & Sons Ltd.

Species composition of and fumonisin production by the Fusarium fujikuroi species complex isolated from Korean cereals.

PubMed

Choi, Jung-Hye; Lee, Seolhee; Nah, Ju-Young; Kim, Hee-Kyoung; Paek, Ji-Seon; Lee, Soohyung; Ham, Hyeonheui; Hong, Sung Kee; Yun, Sung-Hwan; Lee, Theresa

2018-02-21

To assess the risk of fumonisin contamination in Korean cereals, we isolated colonies of the Fusarium fujikuroi species complex (FFSC) from barley, maize, rice and soybean samples from 2011 to 2015. A total of 878 FFSC strains were isolated mostly from maize and rice, and species identity of the isolates were determined using the DNA sequence of the translation elongation factor 1-α (TEF-1α) and RNA polymerase II (RPB2) genes. Fusaria recovered from Korean cereals included F. fujikuroi (317 isolates and a frequency of 36%), F. proliferatum (212 isolates and 24.1%), F. verticillioides (170 isolates and 19.4%), F. concentricum (86 strains and 9.8%), F. andiyazi (56 isolates and 6.4%), F. subglutinans (28 isolates and 3.2%), F. thapsinum (5 isolates and 0.6%), and F. circinatum (2 isolates and 0.2%). The rice samples were dominated by F. fujikuroi (47.4%), F. proliferatum (27.3%), and F. concentricum (15.1%), whereas maize samples were dominated by F. verticillioides (33.9%), F. fujikuroi (25.3%), and F. proliferatum (21.1%). A phylogenetic analysis of 70 representative isolates demonstrated that each species was resolved as genealogically exclusive in the ML tree. Fumonisin production potential was evaluated using a PCR assay for the fumonisin biosynthesis gene, FUM1 in all of the isolates. Most of the isolates tested (94%) were positive for FUM1. All of the isolates assigned to F. fujikuroi, F. proliferatum, F. verticillioides and F. thapsinum were positive for FUM1 irrespective of their host origin. Seventy-seven representative isolates positive for FUM1 were examined for fumonisin production in rice medium. The majority of F. proliferatum (26/27, 96.3%), F. verticillioides (16/17, 94.1%) and F. fujikuroi (19/25, 76.0%) produced both FB 1 and FB 2 . Notably, 16 of 19 fumonisin-producing F. fujikuroi produced >1000μg/g of fumonisins (FB 1 +FB 2 ) in rice medium, which is higher than that in previous reports. These results suggest that F. fujikuroi can produce high levels of fumonisins similar to F. verticillioides and F. proliferatum. Copyright © 2017 Elsevier B.V. All rights reserved.

Clinical and molecular epidemiology of veterinary blastomycosis in Wisconsin.

PubMed

Anderson, Jennifer L; Sloss, Brian L; Meece, Jennifer K

2013-04-22

Several studies have shown that Blastomyces dermatitidis, the etiologic agent of blastomycosis, is a genetically diverse pathogen. Blastomycosis is a significant health issue in humans and other mammals. Veterinary and human isolates matched with epidemiological case data from the same geographic area and time period were used to determine: (i) if differences in genetic diversity and structure exist between clinical veterinary and human isolates of B. dermatitidis and (ii) if comparable epidemiologic features differ among veterinary and human blastomycosis cases. Genetic typing of 301 clinical B. dermatitidis isolates produced 196 haplotypes (59 unique to veterinary isolates, 134 unique to human isolates, and 3 shared between canine and human isolates). Private allelic richness was higher in veterinary (median 2.27) compared to human isolates (median 1.14) (p = 0.005). Concordant with previous studies, two distinct genetic groups were identified among all isolates. Genetic group assignment was different between human and veterinary isolates (p < 0.001), with more veterinary isolates assigned to Group 2. The mean age of dogs diagnosed with blastomycosis was 6 years. Thirty cases were in male dogs (52%) and 24 were females (41%). The breed of dog was able to be retrieved in 38 of 58 cases with 19 (50%) being sporting breeds. Three of four felines infected with blastomycosis were domestic shorthair males between ages 6-12, and presented with disseminated disease. The other was a lynx with pulmonary disease. The equine isolate was from an 11-year-old male Halflinger with disseminated disease. Disseminated disease was reported more often in veterinary (62%) than human cases (19%) (p < 0.001). Isolates from all hosts clustered largely into previously identified genetic groups, with 3 haplotypes being shared between human and canine isolates confirming that B. dermatitidis isolates capable of infecting both species occur in nature. Allelic diversity measures trended higher in veterinary samples, with a higher number of total alleles and private alleles. Veterinary isolates of B. dermatitidis contributed a substantial amount of diversity to the overall population genetic structure demonstrating the importance of including veterinary isolates in genetic studies of evolution and virulence in this organism.

Clinical test to detect mecA and antibiotic resistance in Staphylococcus aureus, based on novel biotechnological methods.

PubMed

Shahmohammadi, Mohammad Reza; Nahaei, Mohammad Reza; Akbarzadeh, Abolfazl; Milani, Morteza

2016-09-01

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common organisms isolated from clinical samples, and has been associated with morbidity and mortality among hospitalized patients. The aim of this study was to evaluate the prevalence and antibiotic susceptibility patterns among MRSA and methicillin-sensitive S. aureus (MSSA) isolates collected from four hospitals in Iran. A total of 183 isolates of S. aureus were collected from various clinical specimens of four hospitals in Iran. The isolates were identified by using the conventional biochemical tests. Three methods-oxacillin agar disk diffusion, oxacillin agar screening, and PCR- were applied to determine susceptibility to oxacillin. The conventional disk agar diffusion test was used to evaluate the antibiotic sensitivity of our isolates against 15 antibiotics, according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Of 183 isolates, 77 isolates (42.1%) were found to be MRSA, by the PCR method. The highest antibiotic resistance was found to be against penicillin, co-trimoxazole, erythromycin, and tetracycline respectively. All isolates were susceptible to vancomycin, according to the results of disk agar diffusion. Among other antibiotics, teicoplanin (84%) and fusidic acid (80.5%) were more active against MRSA isolates. For the different methods evaluated, the sensitivities and specificities were as follows: for disk agar diffusion (84.9% and 95.9%) and for agar screening test with oxacillin concentrations of 0.6 μg/ml (70.8% and 97.4%), 4 μg/ml (96.1%and 97.2%) and 6 μg/ml (96% and 96.3%), respectively. The results of our study showed that 47% of S. aureus isolates were MRSA. Overall, in this research study, resistance to all test antimicrobial agents in MRSA isolates were higher than that of MSSA isolates. Our results also revealed that 85% of mecA-positive isolates and 15% of mecA-negative isolates were resistant to methicillin; while 96% of mecA-negative isolates were sensitive to methicillin. Meanwhile 4% of mecA-positive isolates were also sensitive to methicillin.

Prototheca zopfii genotypes isolated from cow barns and bovine mastitis in Japan.

PubMed

Osumi, Takafumi; Kishimoto, Yuji; Kano, Rui; Maruyama, Haruhiko; Onozaki, Masanobu; Makimura, Koichi; Ito, Takaaki; Matsubara, Kiyoshi; Hasegawa, Atsuhiko

2008-10-15

This study is the first investigation on Japanese isolates of Prototheca zopfii from bovine mastitis and the cow-barn surroundings by molecular characterization to clarify routes of infection for bovine protothecal mastitis. We performed isolation of Prototheca from cow-barn surroundings (drinking water, sewage and feces) and milk samples from cases of bovine mastitis. Genotypes of the 32 isolates of P. zopfii from cow-barn surroundings and 67 isolates from mastitis were analyzed by genotype-specific PCR assays and restriction fragment length polymorphism (RFLP) assays. All mastitis isolates were identified as P. zopfii genotype 2. Conversely, 29 isolates from cow-barn surroundings were identified as P. zopfii genotypes 1 and 3 isolates as genotype 2, respectively. Given these results, both genotypes of P. zopfii could exist in cow-barn surroundings, but no sites were identified as frequent sources of P. zopfii genotype 2. P. zopfii isolates should thus be further explored with regard to genotype to clarify the reservoir of etiological agents in bovine Prototheca mastitis.

Analysis and Design of Bridgeless Switched Mode Power Supply for Computers

NASA Astrophysics Data System (ADS)

Singh, S.; Bhuvaneswari, G.; Singh, B.

2014-09-01

Switched mode power supplies (SMPSs) used in computers need multiple isolated and stiffly regulated output dc voltages with different current ratings. These isolated multiple output dc voltages are obtained by using a multi-winding high frequency transformer (HFT). A half-bridge dc-dc converter is used here for obtaining different isolated and well regulated dc voltages. In the front end, non-isolated Single Ended Primary Inductance Converters (SEPICs) are added to improve the power quality in terms of low input current harmonics and high power factor (PF). Two non-isolated SEPICs are connected in a way to completely eliminate the need of single-phase diode-bridge rectifier at the front end. Output dc voltages at both the non-isolated and isolated stages are controlled and regulated separately for power quality improvement. A voltage mode control approach is used in the non-isolated SEPIC stage for simple and effective control whereas average current control is used in the second isolated stage.

Social isolation, survey nonresponse, and nonresponse bias: An empirical evaluation using social network data within an organization.

PubMed

Watanabe, Megumi; Olson, Kristen; Falci, Christina

2017-03-01

Survey researchers have long hypothesized that social isolation negatively affects the probability of survey participation and biases survey estimates. Previous research, however, has relied on proxy measures of isolation, such as being a marginalized group member within a population. We re-examine the relationship between social isolation and survey participation using direct measures of social isolation derived from social network data; specifically, instrumental research and expressive friendship connections among faculty within academic departments. Using a reconceptualization of social isolation, we find that social network isolation is negatively associated with unit response. Among women (a numerical minority group within the organization), we further find that social group isolation (i.e., lacking instrumental network connections to men, the majority group in the organization) is negatively associated with survey participation. Finally, we show that some survey estimates are systematically biased due to nonparticipation from socially isolated people. Copyright © 2016 Elsevier Inc. All rights reserved.

Cultured bacterial diversity and human impact on alpine glacier cryoconite.

PubMed

Lee, Yung Mi; Kim, So-Yeon; Jung, Jia; Kim, Eun Hye; Cho, Kyeung Hee; Schinner, Franz; Margesin, Rosa; Hong, Soon Gyu; Lee, Hong Kum

2011-06-01

The anthropogenic effect on the microbial communities in alpine glacier cryoconites was investigated by cultivation and physiological characterization of bacteria from six cryoconite samples taken at sites with different amounts of human impact. Two hundred and forty seven bacterial isolates were included in Actinobacteria (9%, particularly Arthrobacter), Bacteroidetes (14%, particularly Olleya), Firmicutes (0.8%), Alphaproteobacteria (2%), Betaproteobacteria (16%, particularly Janthinobacterium), and Gammaproteobacteria (59%, particularly Pseudomonas). Among them, isolates of Arthrobacter were detected only in samples from sites with no human impact, while isolates affiliated with Enterobacteriaceae were detected only in samples from sites with strong human impact. Bacterial isolates included in Actinobacteria and Bacteroidetes were frequently isolated from pristine sites and showed low maximum growth temperature and enzyme secretion. Bacterial isolates included in Gammaproteobacteria were more frequently isolated from sites with stronger human impact and showed high maximum growth temperature and enzyme secretion. Ecotypic differences were not evident among isolates of Janthinobacterium lividum, Pseudomonas fluorescens, and Pseudomonas veronii, which were frequently isolated from sites with different degrees of anthropogenic effect.

Design and test of aircraft engine isolators for reduced interior noise

NASA Technical Reports Server (NTRS)

Unruh, J. F.; Scheidt, D. C.

1982-01-01

Improved engine vibration isolation was proposed to be the most weight and cost efficient retrofit structure-borne noise control measure for single engine general aviation aircraft. A study was carried out the objectives: (1) to develop an engine isolator design specification for reduced interior noise transmission, (2) select/design candidate isolators to meet a 15 dB noise reduction design goal, and (3) carry out a proof of concept evaluation test. Analytical model of the engine, vibration isolators and engine mount structure were coupled to an empirical model of the fuselage for noise transmission evaluation. The model was used to develop engine isolator dynamic properties design specification for reduced noise transmission. Candidate isolators ere chosen from available product literature and retrofit to a test aircraft. A laboratory based test procedure was then developed to simulate engine induced noise transmission in the aircraft for a proof of concept evaluation test. Three candidate isolator configurations were evaluated for reduced structure-borne noise transmission relative to the original equipment isolators.

Isolation and Identification of Mushroom Pathogens from Agrocybe aegerita

PubMed Central

Choi, Jang-Nam; Sharma, Praveen K.; Lee, Wang-Hyu

2010-01-01

Agrocybe aegerita is an important mushroom cultivated in Korea, with good feel and a peculiar fragrance. A. aegerita can be cultivated throughout the year using culture bottles but is more susceptible to contamination than other mushrooms. Twenty-two pathogens were isolated from the fruiting bodies and compost of A. aegerita, and seven isolates were isolated from Pleurotus ostreatus to compare with the A. aegerita isolates, collected from Gimje, Iksan, Gunsan of Chonbuk, and Chilgok of Gyeongbuk Province in 2009. These isolates were identified based on morphological and molecular characteristics. Of the 29 isolates, 26 were identified as Trichoderma spp. and the remaining three were Aspergillus spp., Mucor spp., and Penicillium spp. A phylogenetic analysis revealed that the 26 isolates of Trichoderma were divided into four taxa, namely T. harzianum, T. pleuroticola, T. longibrachiatum, and T. atroviride. Among the Trichoderma spp., 16 isolates (55.2%) were identified as T. harzianum, six as T. pleuroticola (20.7%), two as T. longibrachiatum, and the remaining two were T. atroviride. PMID:23956671

Upstream thinking and health promotion planning for older adults at risk of social isolation.

PubMed

Wilson, Donna M; Harris, Ashley; Hollis, Vivien; Mohankumar, Deepthi

2011-12-01

To raise awareness of social isolation, and provide an approach to first conceptualise and then prevent social isolation among older community-dwelling persons. Older adults comprise a vulnerable population for social isolation and its associated health risks. Literature review. Canada's Population Health Promotion Model was chosen as a comprehensive tool to understand and prevent social isolation. Research studies were sought to identify key health determinants and evidence-based options for preventing social isolation. Around 1 out of 6 older persons are socially isolated and three health determinants are of prime importance: (i) income and social status; (ii) personal health practices and coping skills and (iii) social support networks. Evidence-based interventions targeted to these health determinants are suggested. Nurses are a key group to advocate for actions needed to prevent social isolation. Nurses can play a vital role in minimising social isolation through a variety of educational, prevention and political lobbying activities. © 2010 Blackwell Publishing Ltd.

Molecular variability analysis of five new complete cacao swollen shoot virus genomic sequences.

PubMed

Muller, E; Sackey, S

2005-01-01

Cacao swollen shoot virus (CSSV), a member of the family Caulimovi-ridae, genus Badnavirus occurs in all the main cacao-growing areas of West Africa. We amplified, cloned and sequenced complete genomes of five new isolates, two originating from Togo and three originating from Ghana. The genome of these five newly sequenced isolates all contain the five putative open reading frames I, II, III, X and Y described for the first sequenced CSSV isolate, Agou1 originating from Togo. Their genomes have been aligned with the genome of Agou1. The nucleotide and amino acid sequence identities between isolates have been calculated and a phylogenetic analysis has been made including other pararetroviruses. Maximum nucleotide sequence variability between complete genomes of CSSV isolates was 29.4%. Geographical differentiation between isolates appears more important than differentiation between mild and severe isolates. ORF X differs greatly in size and sequence between the Togolese isolates Nyongbo2 and Agou1, and the four other isolates, its functional role is therefore clearly questionable.

Micro-jitter attenuation of spaceborne cooler by using a blade-type hyperelastic shape memory alloy passive isolator

NASA Astrophysics Data System (ADS)

Kwon, Seong-Cheol; Jeon, Young-Hyeon; Oh, Hyun-Ung

2017-10-01

In this study, the primary design objective is to develop a passive isolator that can guarantee structural safety of the cooler assembly in a launch vibration environment without a launch locking mechanism, while effectively isolating the cooler-induced micro-jitter during the on-orbit operation of the cooler. To achieve the design objective, we focused on the utilization of characteristics of the hyperelastic shape memory effects. The major advantage of the isolator is that the micro-jitter isolation performance is much less sensitive to the aligned position of the isolator in comparison with the conventional isolator. Moreover, implementation of an additional 0g compensation device during a satellite level on-ground test, such as a jitter measurement test, is not required. In this study, the basic characteristics of the isolator were measured using the torque test and free vibration test. The micro-jitter attenuation capability and position sensitivity of the proposed isolator design were validated by the micro-jitter measurement test.

Multilocus Sequence Types of Campylobacter jejuni Isolates from Different Sources in Eastern China.

PubMed

Zhang, Gong; Zhang, Xiaoyan; Hu, Yuanqing; Jiao, Xin-An; Huang, Jinlin

2015-09-01

Campylobacter jejuni is a major food-borne pathogen that causes human gastroenteritis in many developed countries. In our study, we applied multilocus sequence typing (MLST) technology to 167 C. jejuni isolates from diverse sources in Eastern China to examine their genetic diversity. MLST defined 94 sequence types (STs) belonging to 18 clonal complexes (CCs). Forty-five STs from 60 isolates (36%) and 22 alleles have not been previously documented in an international database. One hundred and two isolates, accounting for 61.1% of all isolates, belonged to eight clonal complexes. The eight major CCs were also the most common complexes from different sources. The most common ST type of isolates from human and food was ST-353. The dominant ST type in chicken and foods was ST-354. Among 21 STs that contained two or more different sources isolates, 15 STs contained human isolates and isolates from other sources, suggesting that potentially pathogenic strains are not restricted to specific lineages.

Characterization of Pasteurella multocida isolates from wetland ecosystems during 1996 to 1999

USGS Publications Warehouse

Samuel, M.D.; Shadduck, D.J.; Goldberg, Diana R.; Wilson, M.A.; Joly, D.O.; Lehr, M.A.

2003-01-01

We cultured 126 Pasteurella multocida isolates, 92 from water and 34 from sediment samples collected from wetlands in the Pacific and Central flyways of the United States between 1996 and 1999. Most (121) of the isolates were P. multocida serotype 1, but serotypes 3, 3/4, 10, and 11 were also found. Many (82) of the isolates were further characterized by DNA fingerprinting procedures and tested in Pekin ducks for virulence. Almost all the serotype 1 isolates we tested caused mortality in Pekin ducks. Serotype 1 isolates varied in virulence, but the most consistent pattern was higher mortality in male ducks than in females. We found no evidence that isolates found in sediment vs. water, between Pacific and Central flyways, or during El Nino years had consistently different virulence. We also found a number of non-serotype 1 isolates that were avirulent in Pekin ducks. Isolates had DNA fingerprint profiles similar to those found in birds that died during avian cholera outbreaks.

Isolation and characterisation of obligately anaerobic, lipolytic bacteria from the rumen of red deer.

PubMed

Jarvis, G N; Strömpl, C; Moore, E R; Thiele, J H

1998-03-01

Two Gram-positive, obligately anaerobic, lipolytic bacteria, isolates LIP4 and LIP5, were obtained from the rumen contents of juvenile red deer. These mesophilic bacterial strains were capable of hydrolysing the neutral lipids, tallow, tripalmitin and oliver oil, into their constituent free long-chain fatty acid and glycerol moieties. The latter compound was dissimilated by both isolates, with isolate LIP4 producing propionate as the predominant product, while isolate LIP5 produced acetate, ethanol and succinate. The lactate-utilising isolate LIP4 grew on a limited range of saccharide substrates including glucose, fructose and ribose, and exhibited an unusual cell wall structure and morphology. The isolate LIP5 grew upon a wider range of saccharides, but was unable to use lactate as a substrate. Based upon phenotypic and 16S rRNA gene sequence analyses, isolate LIP4 clusters with species in the genus Propionibacterium, while isolate LIP5 is a member of clostridial cluster XIVa.

Genotyping Toxoplasma gondii from wildlife in Pennsylvania and identification of natural recombinants virulent to mice.

PubMed

Dubey, J P; Van Why, K; Verma, S K; Choudhary, S; Kwok, O C H; Khan, A; Behinke, M S; Sibley, L D; Ferreira, L R; Oliveira, S; Weaver, M; Stewart, R; Su, C

2014-02-24

Recent studies indicated the predominance of Toxoplasma gondii haplogroup 12 in wildlife in the USA. However, still little is known of the genetic diversity of this parasite circulating in wildlife. In the present study, we tested coyotes (Canis latrans), red foxes (Vulpes vulpes), white-tailed deer (Odocoileus virginianus), and geese (Branta canadensis) from the state of Pennsylvania for T. gondii infection. Antibodies to T. gondii were found in 160 of 367 animals, including 92 (34.5%) of 266 coyotes, 49 (62.0%) of 79 white-tailed deer, 17 (85.0%) of 20 red fox, and two of two Canada geese tested by the modified agglutination test (cut off titer 1:25). Tissues from 105 seropositive animals were bioassayed in mice, and viable T. gondii was isolated from 29 animals, including 10 of 53 coyotes, 11 of 16 foxes, 7 of 49 deer, and one of one goose. DNA isolated from culture-derived tachyzoites of these isolates was characterized initially using multilocus PCR-RFLP markers. Nine genotypes were revealed, including ToxoDB PCR-RFLP #1 (4 isolates), #2 (2 isolates), #3 (4 isolates), #4 (6 isolates), #5 (4 isolates), #54 (1 isolate), #141 (1 isolate), #143 (1 isolate), and #216 (6 isolates), indicating high genetic diversity of T. gondii in wildlife in Pennsylvania. Pathogenicity of six T. gondii isolates (5 of #216 and #141) was determined in outbred Swiss Webster mice. Three of #216 and the #141 isolates were acute virulent to mice, and the other 2 #216 isolates were intermediate virulent. To determine the extent of genetic variation of these as well as a few recently reported virulent isolates from wildlife in North America, intron sequences were generated. Analysis of intron sequences and PCR-RFLP genotyping results indicated that the #216 isolates are likely derived from recombination of the clonal type I and III lineages. To determine if T. gondii virulence can be predicted by typing, we genotyped a collection of strains using PCR-RFLP markers for polymorphic genes ROP5, ROP16, ROP18 and GRA15, which are known to interact with host immune response. The results showed that there is an association of genotypes of ROP5 and ROP18 with mouse-virulence, however, additional gene(s) may also contribute to virulence in distinct T. gondii genotypes. Published by Elsevier B.V.

Genetics Home Reference: isolated Duane retraction syndrome

MedlinePlus

... Health Conditions Isolated Duane retraction syndrome Isolated Duane retraction syndrome Printable PDF Open All Close All Enable ... view the expand/collapse boxes. Description Isolated Duane retraction syndrome is a disorder of eye movement. This ...

A "Kanes's Dynamics" Model for the Active Rack Isolation System

NASA Technical Reports Server (NTRS)

Hampton, R. David; Beech, Geoffrey

1999-01-01

Many microgravity space-science experiments require vibratory acceleration levels unachievable without active isolation. The Boeing Corporation's Active Rack Isolation System (ARIS) employs a novel combination of magnetic actuation and mechanical linkages, to address these isolation requirements on the International Space Station (ISS). ARIS provides isolation at the rack (international Standard Payload Rack, or ISPR) level. Effective model-based vibration isolation requires (1) an appropriate isolation device, (2) an adequate dynamic (i.e., mathematical) model of that isolator, and (3) a suitable, corresponding controller. ARIS provides the ISS response to the first requirement. This paper presents one response to the second, in a state-space framework intended to facilitate an optimal-controls approach to the third. The authors use "Kane's Dynamics" to develop an state-space, analytical (algebraic) set of linearized equations of motion for ARIS.

A "Kane's Dynamics" Model for the Active Rack Isolation System

NASA Technical Reports Server (NTRS)

Hampton, R. D.; Beech, G. S.; Rao, N. N. S.; Rupert, J. K.; Kim, Y. K.

2001-01-01

Many microgravity space science experiments require vibratory acceleration levels unachievable without active isolation. The Boeing Corporation's Active Rack Isolation System (ARIS) employs a novel combination of magnetic actuation and mechanical linkages to address these isolation requirements on the International Space Station (ISS). ARIS provides isolation at the rack (International Standard Payload Rack (ISPR)) level. Effective model-based vibration isolation requires: (1) an appropriate isolation device, (2) an adequate dynamic (i.e., mathematical) model of that isolator, and (3) a suitable, corresponding controller. ARIS provides the ISS response to the first requirement. This paper presents one response to the second, in a state space framework intended to facilitate an optimal-controls approach to the third. The authors use "Kane's Dynamics" to develop a state-space, analytical (algebraic) set of linearized equations of motion for ARIS.

Genetic diversity, QoI fungicide resistance, and mating type distribution of Cercospora sojina—Implications for the disease dynamics of frogeye leaf spot on soybean

PubMed Central

Shrestha, Sandesh Kumar; Cochran, Alicia; Mengistu, Alemu; Castro-Rocha, Arturo; Young-Kelly, Heather

2017-01-01

Frogeye leaf spot (FLS), caused by Cercospora sojina, causes significant damage to soybean in the U.S. One control strategy is the use of quinone outside inhibitor (QoI) fungicides. QoI resistant isolates were first reported in Tennessee (TN) in 2010. To investigate the disease dynamics of C. sojina, we collected 437 C. sojina isolates in 2015 from Jackson and Milan, TN and used 40 historical isolates collected from 2006–2009 from TN and ten additional states for comparison. A subset of 186 isolates, including historical isolates, were genotyped for 49 single nucleotide polymorphism (SNP) markers and the QoI resistance locus, revealing 35 unique genotypes. The genotypes clustered into three groups with two groups containing only sensitive isolates and the remaining group containing all resistant isolates and a dominant clonal lineage of 130 isolates. All 477 C. sojina isolates were genotyped for the QoI locus revealing 344 resistant and 133 sensitive isolates. All isolates collected prior to 2015 were QoI sensitive. Both mating type alleles (MAT1-1-1 and MAT1-2) were found in Jackson and Milan, TN and recovered from single lesions suggesting sexual recombination may play a role in the epidemiology of field populations. Analysis of C. sojina isolates using SNP markers proved useful to investigate population diversity and to elaborate on diversity as it relates to QoI resistance and mating type. PMID:28486517

Novel Aminoglycoside Resistance Transposons and Transposon-Derived Circular Forms Detected in Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates

PubMed Central

Dwibedi, Chinmay Kumar; Sjöström, Karin; Edquist, Petra; Wai, Sun Nyunt; Uhlin, Bernt Eric

2016-01-01

Acinetobacter baumannii has emerged as an important opportunistic pathogen equipped with a growing number of antibiotic resistance genes. Our study investigated the molecular epidemiology and antibiotic resistance features of 28 consecutive carbapenem-resistant clinical isolates of A. baumannii collected throughout Sweden in 2012 and 2013. The isolates mainly belonged to clonal complexes (CCs) with an extensive international distribution, such as CC2 (n = 16) and CC25 (n = 7). Resistance to carbapenems was related to blaOXA-23 (20 isolates), blaOXA-24/40-like (6 isolates), blaOXA-467 (1 isolate), and ISAba1-blaOXA-69 (1 isolate). Ceftazidime resistance was associated with blaPER-7 in the CC25 isolates. Two classical point mutations were responsible for resistance to quinolones in all the isolates. Isolates with high levels of resistance to aminoglycosides carried the 16S rRNA methylase armA gene. The isolates also carried a variety of genes encoding aminoglycoside-modifying enzymes. Several novel structures involved in aminoglycoside resistance were identified, including Tn6279, ΔTn6279, Ab-ST3-aadB, and different assemblies of Tn6020 and TnaphA6. Importantly, a number of circular forms related to the IS26 or ISAba125 composite transposons were detected. The frequent occurrence of these circular forms in the populations of several isolates indicates a potential role of these circular forms in the dissemination of antibiotic resistance genes. PMID:26824943

Strain variation in Mycobacterium marinum fish isolates.

PubMed

Ucko, M; Colorni, A; Kvitt, H; Diamant, A; Zlotkin, A; Knibb, W R

2002-11-01

A molecular characterization of two Mycobacterium marinum genes, 16S rRNA and hsp65, was carried out with a total of 21 isolates from various species of fish from both marine and freshwater environments of Israel, Europe, and the Far East. The nucleotide sequences of both genes revealed that all M. marinum isolates from fish in Israel belonged to two different strains, one infecting marine (cultured and wild) fish and the other infecting freshwater (cultured) fish. A restriction enzyme map based on the nucleotide sequences of both genes confirmed the divergence of the Israeli marine isolates from the freshwater isolates and differentiated the Israeli isolates from the foreign isolates, with the exception of one of three Greek isolates from marine fish which was identical to the Israeli marine isolates. The second isolate from Greece exhibited a single base alteration in the 16S rRNA sequence, whereas the third isolate was most likely a new Mycobacterium species. Isolates from Denmark and Thailand shared high sequence homology to complete identity with reference strain ATCC 927. Combined analysis of the two gene sequences increased the detection of intraspecific variations and was thus of importance in studying the taxonomy and epidemiology of this aquatic pathogen. Whether the Israeli M. marinum strain infecting marine fish is endemic to the Red Sea and found extremely susceptible hosts in the exotic species imported for aquaculture or rather was accidentally introduced with occasional imports of fingerlings from the Mediterranean Sea could not be determined.

Genetic diversity among sea otter isolates of Toxoplasma gondii

USGS Publications Warehouse

Sundar, N.; Cole, Rebecca A.; Thomas, N.J.; Majumdar, D.; Dubey, J.P.; Su, C.

2008-01-01

Sea otters (Enhydra lutris) have been reported to become infected with Toxoplasma gondiiand at times succumb to clinical disease. Here, we determined genotypes of 39 T. gondiiisolates from 37 sea otters in two geographically distant locations (25 from California and 12 from Washington). Six genotypes were identified using 10 PCR-RFLP genetic markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico, and by DNA sequencing of loci SAG1 and GRA6 in 13 isolates. Of these 39 isolates, 13 (33%) were clonal Type II which can be further divided into two groups at the locus Apico. Two of the 39 isolates had Type II alleles at all loci except a Type I allele at locus L358. One isolate had Type II alleles at all loci except the Type I alleles at loci L358 and Apico. One isolate had Type III alleles at all loci except Type II alleles at SAG2 and Apico. Two sea otter isolates had a mixed infection. Twenty-one (54%) isolates had an unique allele at SAG1 locus. Further genotyping or DNA sequence analysis for 18 of these 21 isolates at loci SAG1 and GRA6 revealed that there were two different genotypes, including the previously identified Type X (four isolates) and a new genotype named Type A (14 isolates). The results from this study suggest that the sea otter isolates are genetically diverse.

Comparative study of the functional properties of three legume seed isolates: adzuki, pea and soy bean.

PubMed

Barac, Miroljub B; Pesic, Mirjana B; Stanojevic, Sladjana P; Kostic, Aleksandar Z; Bivolarevic, Vanja

2015-05-01

The aim of this work was to compare functional properties including solubility, emulsifying and foaming properties of native and thermally treated adzuki, soy and pea protein isolates prepared under the same conditions. These functional properties were tested at four pH values: pH 3.0, pH 5.0, pH 7.0 and pH 8.0. The lowest solubility at all pH values were obtained for isolate of adzuki whereas isolates of soybean had the highest values at almost all pHs. Thermal treatment reduced solubility of soy and pea isolates at all pH values, whereas solubility of adzuki isolate was unchanged, except at pH 8. Native isolate of adzuki had the best emulsifying properties at pH 7.0 whereas at the other pH values some of native pea and soybean protein isolates were superior. After thermal treatment, depending on tested pH and selected variety all of three species could be a good emulsifier. Native soy protein isolates formed the most stable foams at all pHs. Thermal treatment significantly improved foaming properties of adzuki isolate, whereas reduced foaming capacity of soy and pea isolates, but could improve foam stability of these isolates at specific pH. Appropriate selection of legume seed as well as variety could have great importance in achievement of desirable functional properties of final products. All three tested species could find specific application in wide range of food products.

Frequency of resistance in obligate anaerobic bacteria isolated from dogs, cats, and horses to antimicrobial agents.

PubMed

Lawhon, S D; Taylor, A; Fajt, V R

2013-11-01

Clinical specimens from dogs, cats, and horses were examined for the presence of obligate anaerobic bacteria. Of 4,018 specimens cultured, 368 yielded 606 isolates of obligate anaerobic bacteria (248 from dogs, 50 from cats, and 308 from horses). There were 100 specimens from 94 animals from which only anaerobes were isolated (25 dogs, 8 cats, and 61 horses). The most common sites tested were abdominal fluid (dogs and cats) and intestinal contents (horses). The most common microorganism isolated from dogs, cats, and horses was Clostridium perfringens (75, 13, and101 isolates, respectively). The MICs of amoxicillin with clavulanate, ampicillin, chloramphenicol, metronidazole, and penicillin were determined using a gradient endpoint method for anaerobes. Isolates collected at necropsy were not tested for antimicrobial susceptibility unless so requested by the clinician. There were 1/145 isolates tested that were resistant to amoxicillin-clavulanate (resistance breakpoint ≥ 16/8 μg/ml), 7/77 isolates tested were resistant to ampicillin (resistance breakpoint ≥ 2 μg/ml), 4/242 isolates tested were resistant to chloramphenicol (resistance breakpoint ≥ 32 μg/ml), 12/158 isolates tested were resistant to clindamycin (resistance breakpoint ≥ 8 μg/ml), 10/247 isolates tested were resistant to metronidazole (resistance breakpoint ≥ 32 μg/ml), and 54/243 isolates tested were resistant to penicillin (resistance breakpoint ≥ 2 μg/ml). These data suggest that anaerobes are generally susceptible to antimicrobial drugs in vitro.

Vibrio cholerae Serogroup O139: Isolation from Cholera Patients and Asymptomatic Household Family Members in Bangladesh between 2013 and 2014.

PubMed

Chowdhury, Fahima; Mather, Alison E; Begum, Yasmin Ara; Asaduzzaman, Muhammad; Baby, Nabilah; Sharmin, Salma; Biswas, Rajib; Uddin, Muhammad Ikhtear; LaRocque, Regina C; Harris, Jason B; Calderwood, Stephen B; Ryan, Edward T; Clemens, John D; Thomson, Nicholas R; Qadri, Firdausi

2015-11-01

Cholera is endemic in Bangladesh, with outbreaks reported annually. Currently, the majority of epidemic cholera reported globally is El Tor biotype Vibrio cholerae isolates of the serogroup O1. However, in Bangladesh, outbreaks attributed to V. cholerae serogroup O139 isolates, which fall within the same phylogenetic lineage as the O1 serogroup isolates, were seen between 1992 and 1993 and in 2002 to 2005. Since then, V. cholerae serogroup O139 has only been sporadically isolated in Bangladesh and is now rarely isolated elsewhere. Here, we present case histories of four cholera patients infected with V. cholerae serogroup O139 in 2013 and 2014 in Bangladesh. We comprehensively typed these isolates using conventional approaches, as well as by whole genome sequencing. Phenotypic typing and PCR confirmed all four isolates belonging to the O139 serogroup. Whole genome sequencing revealed that three of the isolates were phylogenetically closely related to previously sequenced El Tor biotype, pandemic 7, toxigenic V. cholerae O139 isolates originating from Bangladesh and elsewhere. The fourth isolate was a non-toxigenic V. cholerae that, by conventional approaches, typed as O139 serogroup but was genetically divergent from previously sequenced pandemic 7 V. cholerae lineages belonging to the O139 or O1 serogroups. These results suggest that previously observed lineages of V. cholerae O139 persist in Bangladesh and can cause clinical disease and that a novel disease-causing non-toxigenic O139 isolate also occurs.

A prospective study on evaluation of pathogenesis, biofilm formation, antibiotic susceptibility of microbial community in urinary catheter

NASA Astrophysics Data System (ADS)

Younis, Khansa Mohammed; Usup, Gires; Ahmad, Asmat

2015-09-01

This study is aimed to isolate, detect biofilm formation ability and antibiotic susceptibility of urinary catheter adherent microorganisms from elderly hospitalized patient at the Universiti Kebangsaan Malaysia Medical Center. Microorganisms were isolated from three samples of urinary catheters (UC) surface; one of the acute vascular rejection patient (UCB) and two from benign prostate hyperplasia patients (UCC and UCD). A total of 100 isolates was isolated with 35 from UCB, 38 (UCC) and 28 (UCD). Ninety six were identified as Gram-negative bacilli, one Gram-positive bacilli and three yeasts. Results of biofilm forming on sterile foley catheter showed that all the isolates can form biofilm at different degrees; strong biofilm forming: 32% from the 35 isolates (UCB), 25% out of 38 isolates (UCC), 26% out of 28 isolates (UCD). As for moderate biofilm forming; 3% from UCB, 10% from UCC and 2% from UCD. Weak biofilm forming in UCC (3%). The antibiotic susceptibility for (UCB) isolates showed highly resistant to ampicillin, novobiocin and penicillin 100 (%), kanamycin (97%), tetracycline (94%), chloramphenicol (91%), streptomycin (77%) and showed low level of resistance to gentamycin (17%), while all the isolates from (UCC-D) showed high resistant towards ampicillin and penicillin, novobiocin (94%), tetracycline (61%), streptomycin (53%), gentamycin (50%) and low level of resistance to kanamycin (48%), chloramphenicol (47%). The findings indicate that these isolates can spread within the community on urinary catheters surface and produce strong biofilm, therefore, monitoring antibiotic susceptibility of bacteria isolated in the aggregation is recommended.

Characterization and zoonotic potential of uropathogenic Escherichia coli isolated from dogs.

PubMed

Nam, Eui-Hwa; Ko, Sungjin; Chae, Joon-Seok; Hwang, Cheol-Yong

2013-03-01

The aim of this study was to investigate the characteristics of canine uropathogenic Escherichia coli (UPEC) and the interaction between canine UPEC and human bladder epithelial cells. Ten E. coli isolates collected from dogs with cystitis were analyzed for antimicrobial resistance patterns, the presence of virulence factors, and biofilm formation. The ability of these isolates to induce cytotoxicity, invade human bladder epithelial cells, and stimulate an immune response was also determined. We observed a high rate of antimicrobial resistance among canine UPEC isolates. All virulence genes tested (including adhesins, iron acquisition, and protectin), except toxin genes, were detected among the canine UPEC isolates. We found that all isolates showed varying degrees of biofilm formation (mean, 0.26; range, 0.07 to 0.82), using a microtiter plate assay to evaluate biofilm formation by the isolates. Cytotoxicity to human bladder epithelial cells by the canine UPEC isolates increased in a time-dependent manner, with a 56.9% and 36.1% reduction in cell viability compared with the control at 6 and 9 h of incubation, respectively. We found that most canine UPEC isolates were able to invade human bladder epithelial cells. The interaction between these isolates and human bladder epithelial cells strongly induced the production of proinflammatory cytokines such as IL-6 and IL-8. We demonstrated that canine UPEC isolates can interact with human bladder epithelial cells, although the detailed mechanisms remain unknown. The results suggest that canine UPEC isolates, rather than dogspecific pathogens, have zoonotic potential.

Emergence of Carbapenem-Resistant Pseudomonas aeruginosa and Acinetobacter baumannii Clinical Isolates Collected from Some Libyan Hospitals.

PubMed

Mathlouthi, Najla; Areig, Zaynab; Al Bayssari, Charbel; Bakour, Sofiane; Ali El Salabi, Allaaeddin; Ben Gwierif, Salha; Zorgani, Abdulaziz A; Ben Slama, Karim; Chouchani, Chedly; Rolain, Jean-Marc

2015-06-01

The aim of the present study was to investigate the molecular mechanism of carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii clinical isolates recovered from Libyan hospitals between April 2013 and April 2014. In total, 49 strains (24 P. aeruginosa and 25 A. baumannii) were isolated, including 21 P. aeruginosa and 22 A. baumannii isolates (87.75%) resistant to imipenem (minimum inhibitory concentrations ≥16 μg/ml). The blaVIM-2 gene was detected in 19 P. aeruginosa isolates. All imipenem-resistant P. aeruginosa isolates showed the presence of OprD mutations. Acquired OXA-carbapenemase-encoding genes were present in all A. baumannii isolates: blaOXA-23 (n=19) and blaOXA-24 (n=3). Finally, a total of 13 and 17 different sequence types were assigned to the 21 P. aeruginosa and the 22 A. baumannii carbapenem-resistant isolates, respectively. This study is the first report describing imipenem-resistant P. aeruginosa and A. baumannii isolated from patients in Libya. We report the first case of co-occurrence of blaVIM-2 with oprD porin loss in identical isolates of P. aeruginosa in Libya and demonstrate that these oprD mutations can be used as a tool to study the clonality in P. aeruginosa isolates. We also report the first identification of multidrug-resistant A. baumannii isolates harboring blaOXA-23-like, blaOXA-24-like, and blaOXA-48-like genes in Libya.

Isolation of Ganjam virus from ticks collected off domestic animals around Pune, Maharashtra, India.

PubMed

Joshi, M V; Geevarghese, G; Joshi, G D; Ghodke, Y S; Mourya, D T; Mishra, A C

2005-03-01

Studies on viruses of zoonotic importance in certain villages around Pune were undertaken between December 2000 and January 2002. A total of 1,138 adult ticks belonging to six different species were collected off domestic animals and processed for virus isolation. Six virus isolates were obtained. All six isolates were identified as Ganjam virus by Quick Complement Fixation test and reverse transcriptase-polymerase chain reaction using RNA nucleocapsid gene amplification. Five isolates were from the pools of adult Hemaphysalis intermedia ticks, and one isolate was from a pool of adult Rhipecephalus hemaphysaloides. This is the first report of isolation of Ganjam virus from Maharashtra state of India.

Method for isolating nucleic acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hurt, Jr., Richard Ashley; Elias, Dwayne A.

The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids formore » a wide variety of applications including, sequencing or species population analysis.« less

Shock isolator for diode laser operation on a closed-cycle refrigerator

NASA Technical Reports Server (NTRS)

Jennings, D. E.; Hillman, J. J.

1977-01-01

Closed-cycle helium refrigerators are widely used as coolers for semiconductor diode lasers. These refrigerators pose several difficulties including temperature oscillations due to varying refrigerator capacity during the Solvay cycle, and impact shocks delivered to the diode in the cycle's expansion phase. A shock isolator has been designed to isolate diode lasers from such impact shocks. Slow diode current scans have been made before installation of the shock isolator, with the isolator but no thermal damper, and with both devices. With the isolator and no damper, the diode output frequency oscillated at the refrigerator cycle rate, deviating by plus or minus 40 MHz. Using the isolator and the damper no frequency fluctuation was detected.

[Tracing to the source of staphylococcus aureus isolates from ice cream].

PubMed

Zhang, Yan-Jun; Xu, Dan-Ge; Fang, Ye-Zhen; Gong, Pu; Zhu, Min; Bao, Fang-Zhen

2008-07-01

To investigate the contamination of Staphylococcus aureus isolates in ice cream by phenotypic typing and molecular typing. The Staphylococcus aureus isolates were separated from ice cream, filler, cutter, salves and material. The separated isolates were characterized by drug-resistance, staphylococcal enterotoxin (SEA-E), SE (A-E, G-J) genes and pulsed-field gel electrophoresis (PFGE) types. Two Staphylococcus aureus isolates were separated, one from ice cream, another from cutter. Their characteristics of drug-resistance, staphylococcal enterotoxin (SEA-E), SE (A-E,G-J) genes and PFGE type were the same. The two Staphylococcus aureus isolates were the same clone. The contaminated Staphylococcus aureus isolates could be traced to the contaminated cutters.

Whole-Genome Sequencing Reveals Laboratory Salmonella Typhimurium Strain 14028s as a Likely Source of Outbreak Isolates from 2009-2010

USDA-ARS?s Scientific Manuscript database

Background: Next-generation sequencing (NGS) of bacterial isolates has emerged as valuable tool for tracking of an outbreak source. Between 2009 and 2011, clinical isolates of Salmonella Typhimurium sharing the JPXX01.0014 (XbaI) PFGE type were isolated across the U.S. The initial isolates were asso...

Racial Isolation in the Rochester Public Schools: The Problem and What to Do About It. Special Report.

ERIC Educational Resources Information Center

Urban League of Rochester, Inc., NY.

This report focuses on initiatives which might be taken by the Rochester Board of Education to reduce racial isolation within the city. Information is provided about the extent of racial isolation in Rochester, the effects of isolation on student achievement, the forces behind minority group isolation, and current policies and programs undertaken…

World Reference Center for Arboviruses.

DTIC Science & Technology

1997-07-01

reagent bank, to identify emerging viruses by antigenic and genetic methods, and (d) ordering and cataloguing the virus collection into a computer...encephalitis viruses in mosquitoes collected in Rhode Island and Connecticut. Eastern equine encephalitis (EKE) virus was isolated from 93 of 1800...Results of ri state mosquito- virus isolation studies Viruses identified Date of first isolation Number of isolations Date of last isolation Other

Characterization of a naturally occurring recombinant isolate of Grapevine fanleaf virus.

PubMed

Vigne, E; Demangeat, G; Komar, V; Fuchs, M

2005-11-01

The naturally occurring Grapevine fanleaf virus (GFLV) recombinant isolate A17b was recovered from its grapevine host by sap inoculation and serial passages onto Gomphrena globosa, a pseudo local lesion herbaceous host, and Chenopodium quinoa, a systemic herbaceous host, to characterize some of its biological properties. Sequence analysis of the CP gene, in which a recombinational event was previously detected, demonstrated the genetic stability of recombinant isolate A17b over a 5-year period in its natural host as well as in C. quinoa. Also, recombinant isolate A17b was graft transmissible, as shown by an in vitro heterologous approach, and transmitted by the nematode Xiphinema index as readily as nonrecombinant GFLV isolates. Furthermore, despite a lower pathogenicity on Chenopodium amaranticolor, recombinant isolate A17b had a similar host range and induced similar symptoms in type and severity to nonrecombinant GFLV isolates. Interestingly, the use of infectious chimeric RNA2 transcripts in combination to RNA1 transcripts of GFLV strain F13 suggested no implication of the recombination event in the CP gene of isolate A17b in the reduced pathogenicity on C. amaranticolor. Altogether, recombinant isolate A17b had similar biological properties to GFLV nonrecombinant isolates.

Characterization of spaC-type Erysipelothrix sp. isolates causing systemic disease in ornamental fish.

PubMed

Pomaranski, E K; Reichley, S R; Yanong, R; Shelley, J; Pouder, D B; Wolf, J C; Kenelty, K V; Van Bonn, B; Oliaro, F; Byrne, B; Clothier, K A; Griffin, M J; Camus, A C; Soto, E

2018-01-01

Since 2012, low-to-moderate mortality associated with an Erysipelothrix sp. bacterium has been reported in ornamental fish. Histological findings have included facial cellulitis, necrotizing dermatitis and myositis, and disseminated coelomitis with abundant intralesional Gram-positive bacterial colonies. Sixteen Erysipelothrix sp. isolates identified phenotypically as E. rhusiopathiae were recovered from diseased cyprinid and characid fish. Similar clinical and histological changes were also observed in zebrafish, Danio rerio, challenged by intracoelomic injection. The Erysipelothrix sp. isolates from ornamental fish were compared phenotypically and genetically to E. rhusiopathiae and E. tonsillarum isolates recovered from aquatic and terrestrial animals from multiple facilities. Results demonstrated that isolates from diseased fish were largely clonal and divergent from E. rhusiopathiae and E. tonsillarum isolates from normal fish skin, marine mammals and terrestrial animals. All ornamental fish isolates were PCR positive for spaC, with marked genetic divergence (<92% similarity at gyrB, <60% similarity by rep-PCR) between the ornamental fish isolates and other Erysipelothrix spp. isolates. This study supports previous work citing the genetic variability of Erysipelothrix spp. spa types and suggests isolates from diseased ornamental fish may represent a genetically distinct species. © 2017 John Wiley & Sons Ltd.

Pathogenic diversity amongst serotype C VGIII and VGIV Cryptococcus gattii isolates

PubMed Central

Rodrigues, Jéssica; Fonseca, Fernanda L.; Schneider, Rafael O.; Godinho, Rodrigo M. da C.; Firacative, Carolina; Maszewska, Krystyna; Meyer, Wieland; Schrank, Augusto; Staats, Charley; Kmetzsch, Livia; Vainstein, Marilene H.; Rodrigues, Marcio L.

2015-01-01

Cryptococcus gattii is one of the causative agents of human cryptococcosis. Highly virulent strains of serotype B C. gattii have been studied in detail, but little information is available on the pathogenic properties of serotype C isolates. In this study, we analyzed pathogenic determinants in three serotype C C. gattii isolates (106.97, ATCC 24066 and WM 779). Isolate ATCC 24066 (molecular type VGIII) differed from isolates WM 779 and 106.97 (both VGIV) in capsule dimensions, expression of CAP genes, chitooligomer distribution, and induction of host chitinase activity. Isolate WM 779 was more efficient than the others in producing pigments and all three isolates had distinct patterns of reactivity with antibodies to glucuronoxylomannan. This great phenotypic diversity reflected in differential pathogenicity. VGIV isolates WM 779 and 106.97 were similar in their ability to cause lethality and produced higher pulmonary fungal burden in a murine model of cryptococcosis, while isolate ATCC 24066 (VGIII) was unable to reach the brain and caused reduced lethality in intranasally infected mice. These results demonstrate a high diversity in the pathogenic potential of isolates of C. gattii belonging to the molecular types VGIII and VGIV. PMID:26153364

Biochemical characters and antibiotic susceptibility of Staphylococcus aureus isolates.

PubMed

Chakraborty, Subhankari Prasad; Mahapatra, Santanu Kar; Roy, Somenath

2011-06-01

To observe the biochemical characters and antibiotic susceptibility of isolated Staphylococcus aureus (S. auerus) strains against some conventional and traditional antibiotics. Thirty post operative pathogenic isolated S. aureus strains were used in this study. Bacterial culture was done in Mueller-Hinton broth at 37 °C. Characters of these strains were determined by traditional biochemical tests such as hydrolysis test of gelatin, urea, galactose, starch and protein, and fermentation of lactose and sucrose. Antibiotic susceptibility were carried out by minimum inhibitory concentration test, minium bactericidal concentration test, disc agar diffusion test and brain heart infusion oxacillin screening agar. From this study, it was observed that 100% S. aureus isolates showed positive results in gelatin, urea and galactose hydrolysis test, 50% isolates were positive in starch hydrolysis test, 35% in protein hydrolysis test, 100% isolates in lactose fermenting test, but no isolate was positive in sucrose fermenting test. Antibiotic susceptibility testing suggested that 20% of isolates were resistant to kanamycin and 46.67% were resistant to oxacillin. These findings show that all these isolates have gelatin, urea, galactose hydrolysis and lactose fermenting activity. 20% of these isolates were resistant to kanamycin and 46.67% were resistant to oxacillin.

Evidence for Geographic Isolation and Signs of Endemism within a Protistan Morphospecies†

PubMed Central

Boenigk, Jens; Pfandl, Karin; Garstecki, Tobias; Harms, Hauke; Novarino, Gianfranco; Chatzinotas, Antonis

2006-01-01

The possible existence of endemism among microorganisms resulting from and preserved by geographic isolation is one of the most controversial topics in microbial ecology. We isolated 31 strains of “Spumella-like” flagellates from remote sampling sites from all continents, including Antarctica. These and another 23 isolates from a former study were characterized morphologically and by small-subunit rRNA gene sequence analysis and tested for the maximum temperature tolerance. Only a minority of the Spumella morpho- and phylotypes from the geographically isolated Antarctic continent follow the worldwide trend of a linear correlation between ambient (air) temperature during strain isolation and heat tolerance of the isolates. A high percentage of the Antarctic isolates, but none of the isolates from locations on all other continents, were obligate psychrophilic, although some of the latter were isolated at low ambient temperatures. The drastic deviation of Antarctic representatives of Spumella from the global trend of temperature adaptation of this morphospecies provides strong evidence for geographic transport restriction of a microorganism; i.e., Antarctic protistan communities are less influenced by transport of protists to and from the Antarctic continent than by local adaptation, a subtle form of endemism. PMID:16885260

Phenotypic and genotypic profile of clinical and animal multidrug-resistant Salmonella enterica isolates from Mexico.

PubMed

Aguilar-Montes de Oca, S; Talavera-Rojas, M; Soriano-Vargas, E; Barba-León, J; Vázquez-Navarrete, J; Acosta-Dibarrat, J; Salgado-Miranda, C

2018-01-01

The objective of this study was to obtain a phenotypic and genotypic profile of Salmonella enterica including multidrug-resistant (MDR) isolates from food-producing animals and clinical isolates, as well as their genetic relatedness in two different States of Mexico (Jalisco and State of Mexico). A total of 243 isolates were evaluated in terms of antimicrobial resistance (AMR) and related genes through a disk diffusion method and PCR respectively; we found 16 MDR isolates, all of them harbouring the bla CMY gene but not qnr genes, these isolates represent less than 10% of the collection. The pulsed-field gel electrophoresis revealed a higher genotypic similitude within isolates of State of Mexico than Jalisco. A low percentage of Salmonella isolates were resistant to relevant antibiotics in human health, nevertheless, the AMR and involved genes were similar despite the different serovars and origin of the isolates. This investigation provided an insight of the current status of AMR of Salmonella isolates in two States of Mexico and pinpoint the genes involved in AMR and their epidemiological relationship, the information could help to determine an adequate therapy in human and veterinary medicine. © 2017 The Society for Applied Microbiology.

Infectious pancreatic necrosis virus in Atlantic salmon, Salmo salar L., post-smolts in the Shetland Isles, Scotland: virus identification, histopathology, immunohistochemistry and genetic comparison with Scottish mainland isolates.

PubMed

Smail, D A; Bain, N; Bruno, D W; King, J A; Thompson, F; Pendrey, D J; Morrice, S; Cunningham, C O

2006-01-01

During mid-June 1999 peak mortalities of 11% of the total stock per week were seen at a sea cage site of Atlantic salmon, Salmo salar L., post-smolts in the Shetland Isles, Scotland. Virus was isolated on chinook salmon embryo (CHSE) cells in a standard diagnostic test and infectious pancreatic necrosis virus (IPNV) identified by enzyme-linked immunosorbent assay. IPNV was confirmed as serogroup A by a cell immunofluorescent antibody test using the cross-reactive monoclonal antibody AS-1. Four weeks after the main outbreak, virus titres in surviving moribund fish were assayed at >10(10) TCID50 g(-1) kidney. Histopathology of moribund fish was characterized by pancreatic acinar cell necrosis and a marked catarrhal enteritis of the intestinal mucosa. In the liver, necrosis, leucocytic infiltration and a generalized cell vacuolation were noted. IPNV-specific immunostaining was demonstrated in pancreas, liver, heart, gill and kidney tissue. The nucleotide sequence of the coding region of segment A was determined from the Shetland isolate. A 1180 bp fragment of the VP2 gene of this isolate was compared with a 1979 reference isolate from mainland Scottish Atlantic salmon, La/79 and another more recent mainland isolate, 432/00. Both A2 isolates were derived from carrier fish without signs of IPN and serotyped by a plaque neutralization test. The Shetland isolate shows a different nucleotide and amino acid sequence compared with the two isolates from carrier fish. These latter isolates showed identical amino acid sequences in the fragment examined, despite the 21 years separating the isolations. Sequence comparisons with other A2 (Sp) isolates on the database confirm all three Scottish isolates are A2 (Sp).

Molecular Phylogenetic Analysis of a Geographically and Temporally Matched Set of Candida albicans Isolates from Humans and Nonmigratory Wildlife in Central Illinois ▿

PubMed Central

Wrobel, Lauren; Whittington, Julia K.; Pujol, Claude; Oh, Soon-Hwan; Ruiz, Marilyn O.; Pfaller, Michael A.; Diekema, Daniel J.; Soll, David R.; Hoyer, Lois L.

2008-01-01

This study explored whether wildlife species serve as the reservoir for human Candida albicans strains in a given geographic area. C. albicans isolates were collected from nonmigratory wildlife admitted to the University of Illinois Wildlife Medical Clinic. A geographically and temporally matched set of C. albicans oral isolates was collected from healthy human volunteers. Multilocus sequence typing was used to assign strains to genetic clades. Clade 1 isolates, particularly diploid sequence type 69 (DST 69), were most common in humans. Clade 1 strains were less frequently recovered from wildlife, while clade 8 strains, particularly DST 90, were overrepresented in the wildlife collection. All instances where a wildlife and human isolate shared the same DST occurred within clade 1. Clade distributions between human and wildlife isolates were significantly different, demonstrating population isolation between the groups. These differences may indicate limited strain transfer between groups or differential selection of C. albicans isolates in humans and wildlife. Wildlife strains had an amphotericin B MIC significantly lower than that of human isolates; strains with increased susceptibility were from several clades. C. albicans isolates were collected from domestic animals to provide comparisons with human and wildlife data sets. C. albicans isolation from canine and feline oral and anal swabs was infrequent; companion animal isolates were closely related to clade 1 human isolates. Collectively, the data suggest a greater likelihood of C. albicans transfer from humans to animals than from animals to humans. The nontransient human population may maintain the connection between geography and the C. albicans genetic groups recovered from humans. PMID:18621922

First isolation and genotyping of Toxoplasma gondii from bats (Mammalia: Chiroptera).

PubMed

Cabral, A D; Gama, A R; Sodré, M M; Savani, E S M M; Galvão-Dias, M A; Jordão, L R; Maeda, M M; Yai, L E O; Gennari, S M; Pena, H F J

2013-03-31

There are currently no reports on the isolation and molecular examination of Toxoplasma gondii from bats. Here, we report the isolation and genotypic characterisation of two T. gondii isolates from bats. A total of 369 bats from different municipalities in São Paulo state, southeastern Brazil, were captured and euthanised, and collected tissues (heart and pectoral muscle) were processed for each bat or in pools of two or three bats and bioassayed in mice (a total of 283 bioassays). Eleven PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) markers were used to genotype positive samples: SAG1, SAG2 (5'-3'SAG2 and alt. SAG2), SAG3, BTUB, GRA6, L358, c22-8, c29-2, PK1, CS3 and Apico. The parasite was isolated from two bats from São Paulo city: an insectivorous bat, the velvety free-tailed bat Molossus molossus, and a hematophagous bat, the common vampire bat Desmodus rotundus. Isolates were designated TgBatBr1 and TgBatBr2, respectively. The genotype of the isolate from M. molossus (TgBatBr1) has been previously described in an isolate from a capybara from São Paulo state, and the genotype from the D. rotundus isolate (TgBatBr2) has already been identified in isolates from cats, chickens, capybaras, sheep, a rodent and a common rabbit from different Brazilian states, suggesting that this may be a common T. gondii lineage circulating in some Brazilian regions. Isolation of T. gondii from a hematophagous species is striking. This study reveals that bats can share the same isolates that are found in domesticated and wild terrestrial animals. This is the first report of the isolation and genotyping of T. gondii in chiropterans. Copyright © 2012 Elsevier B.V. All rights reserved.

Porphyromonas pogonae sp. nov., an anaerobic but low concentration oxygen adapted coccobacillus isolated from lizards (Pogona vitticeps) or human clinical specimens, and emended description of the genus Porphyromonas Shah and Collins 1988.

PubMed

Kawamura, Yoshiaki; Kuwabara, Saki; Kania, Stephen A; Kato, Hisayuki; Hamagishi, Manami; Fujiwara, Nagatoshi; Sato, Takuichi; Tomida, Junko; Tanaka, Kaori; Bemis, David A

2015-03-01

During the process of identifying a Gram-negative coccobacillus isolated from a human clinical specimen, we found that the isolate's 16S rRNA gene had very close sequence identity with that of a variant Porphyromonas isolated from polymicrobial infections in the central bearded dragon, a species of lizard [2]. The 16S rRNA gene sequences of the human isolate and of six isolates from lizards were nearly identical (99.9-100%). Phylogenetic analysis placed all of these isolates in a single phylogenetic cluster well separated from other species in the genus Porphyromonas. The closest species was Porphyromonas catoniae with 90.7-90.9% sequence identity, although there was less than 6% DNA similarity between the P. catoniae type strain and our representative isolates from lizards (PAGU 1787(T)) and human (PAGU 1776). These isolates could grow under anaerobic or microaerobic conditions (6% O2 atmosphere). The isolates were positive for catalase and very strong β-hemolytic activity, but did not show black or brown pigmentation. Biochemically, the isolates could be differentiated from closely related species by pyroglutamic acid arylamidase and glycine arylamidase activity, and some others. The fermentation products mainly included succinic acid and propionic acid. The major fatty acids detected in cells of the isolates were iso-C15:0, anteiso-C15:0, and 3OH-iso-C17:0. The G+C content was 43.0 ± 0.62 mol%. The species name Porphyromonas pogonae sp. nov. is proposed for these isolates with the type strain of PAGU 1787(T) (=MI 10-1288(T)=JCM 19732(T)=ATCC BAA-2643(T)). Copyright © 2014 Elsevier GmbH. All rights reserved.

Toxin-associated and other genes in Clostridium perfringens type A isolates from bovine clostridial abomasitis (BCA) and jejunal hemorrhage syndrome (JHS).

PubMed

Schlegel, Benjamin J; Nowell, Victoria J; Parreira, Valeria R; Soltes, Glenn; Prescott, John F

2012-10-01

This study examined known or possible virulence-associated genes in type A Clostridium perfringens from cases of both bovine clostridial abomasitis (BCA) and jejunal hemorrhage syndrome (JHS) and compared these to isolates from calves that were healthy or had undifferentiated diarrheal illness. A real-time polymerase chain reaction (PCR) assay was used to genotype the 218 C. perfringens isolates. Isolates were sourced from healthy and diarrheic young and mature cattle (n = 191), from calves with confirmed or suspected BCA (n = 22), and from mature cattle with JHS (n = 5). Of 216 isolates (96%), 208 were positive for the cpa gene and 13% (29/218) were positive for atypical cpb2. Three of 8 (37.5%) confirmed BCA isolates, 2 of 13 (15.4%) suspected BCA isolates, and no JHS isolates tested positive for atypical cpb2. As all isolates were negative for cpb, cpb2, cpe, etx, netB, and tpeL, the results of the present study do not support a role for these genes in BCA or JHS. A subset of unique genes identified in 1 bovine clostridial abomasitis isolate (F262), for which a genome sequence is available, was searched for in 8 BCA isolates by PCR. None of the 10 genes was consistently present in all or even in a majority of BCA isolates. Many of these genes were also variably and inconsistently present in type A isolates from calves that did not have BCA. Although a virulence signature to aid in the diagnosis of BCA caused by C. perfringens type A was not identified, further work may discover a gene or group of genes that would constitute such a signature.

Toxin-associated and other genes in Clostridium perfringens type A isolates from bovine clostridial abomasitis (BCA) and jejunal hemorrhage syndrome (JHS)

PubMed Central

Schlegel, Benjamin J.; Nowell, Victoria J.; Parreira, Valeria R.; Soltes, Glenn; Prescott, John F.

2012-01-01

This study examined known or possible virulence-associated genes in type A Clostridium perfringens from cases of both bovine clostridial abomasitis (BCA) and jejunal hemorrhage syndrome (JHS) and compared these to isolates from calves that were healthy or had undifferentiated diarrheal illness. A real-time polymerase chain reaction (PCR) assay was used to genotype the 218 C. perfringens isolates. Isolates were sourced from healthy and diarrheic young and mature cattle (n = 191), from calves with confirmed or suspected BCA (n = 22), and from mature cattle with JHS (n = 5). Of 216 isolates (96%), 208 were positive for the cpa gene and 13% (29/218) were positive for atypical cpb2. Three of 8 (37.5%) confirmed BCA isolates, 2 of 13 (15.4%) suspected BCA isolates, and no JHS isolates tested positive for atypical cpb2. As all isolates were negative for cpb, cpb2, cpe, etx, netB, and tpeL, the results of the present study do not support a role for these genes in BCA or JHS. A subset of unique genes identified in 1 bovine clostridial abomasitis isolate (F262), for which a genome sequence is available, was searched for in 8 BCA isolates by PCR. None of the 10 genes was consistently present in all or even in a majority of BCA isolates. Many of these genes were also variably and inconsistently present in type A isolates from calves that did not have BCA. Although a virulence signature to aid in the diagnosis of BCA caused by C. perfringens type A was not identified, further work may discover a gene or group of genes that would constitute such a signature. PMID:23543949

Screening of antibacterial activity of lactic acid bacteria against different pathogens found in vacuum-packaged meat products.

PubMed

Awaisheh, Saddam S; Ibrahim, Salam A

2009-11-01

The objective of this work was to screen the antibacterial activity of lactic acid bacteria (LAB) isolated from different sources against different pathogens found in ready-to-eat vacuum-packaged meat products (RTE-VPMP). LAB were isolated from human, RTE-VPMP, fermented vegetables, and dairy samples. These isolates were assessed for their antibacterial activity against Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus using spot on lawn technique. Six LAB isolates-three from a human source, two from a RTE-VPMP source, and one from a fermented vegetable source-were found to be effective against all pathogenic strains. Antibacterial activities of cell-free neutral supernatant broths of these isolates were assessed against the different pathogenic strains to confirm bacteriocin production. All six isolates were effective against all pathogenic strains. LAB isolates from the human source had the highest antibacterial activity and were significantly more effective than other LAB isolates, with the inhibition zone ranging from 14 to 22 mm. Inhibition zones of RTE-VPMP LAB isolates were lower than those of human origin (inhibition zone range, 11-17 mm). The lowest activities were for the fermented vegetable isolate, for which inhibition zones ranged from 11 to 15 mm. The three isolates of human origin were identified as L. acidophilus, L. casei, and L. reuteri; the two isolates from RTE-VPMP source were both L. sake; and the one isolate of fermented vegetable origin was L. plantarum. Our results showed that nonmeat product-sourced LAB were effective against several foodborne pathogens, which suggests that they could be used as natural biopreservatives in many RTE-VPMP produced in Jordan.

Prevalence of macrolide-non-susceptible isolates among β-lactamase-negative ampicillin-resistant Haemophilus influenzae in a tertiary care hospital in Japan.

PubMed

Wajima, Takeaki; Seyama, Shoji; Nakamura, Yuka; Kashima, Chihiro; Nakaminami, Hidemasa; Ushio, Masanobu; Fujii, Takeshi; Noguchi, Norihisa

2016-09-01

β-Lactamase-negative ampicillin-resistant (BLNAR) Haemophilus influenzae account for a large portion of H. influenzae clinical isolates in Japan. The aim of this study was to clarify the antimicrobial susceptibility of BLNAR H. influenzae clinical isolates as well as the annual changes in susceptibility. BLNAR H. influenzae isolates were collected from a tertiary care hospital from 2007 to 2012. Antimicrobial susceptibility testing was performed and resistance mechanisms were analysed. All of the isolates (n=304) had amino acid substitutions in penicillin-binding protein 3 (PBP3) and isolates were classified by these amino acid substitutions: R517H or N526K (class I); S385T and R517H (class II); and S385T and N526K (class III). Classes I, II and III represented 8.2% (n=25), 9.5% (n=29) and 81.6% (n=248) of the isolates, respectively; 2 isolates could not be classified because they had a PBP3 with a substantially mutated FtsI transpeptidase domain. All of the isolates were highly susceptible to fluoroquinolones and carbapenems. The number of clarithromycin (CAM)-non-susceptible [minimum inhibitory concentration (MIC) ≥16μg/mL] H. influenzae isolates increased significantly between 2010 and 2012. Moreover, CAM-non-susceptible H. influenzae isolates were prevalent among class II and class III BLNAR H. influenzae. Multilocus sequence typing (MLST) of the CAM-resistant (MIC ≥32μg/mL) H. influenzae isolates showed that they were not specific sequence types, suggesting that CAM resistance may occur in any isolates. These results raise concern regarding the occurrence of multidrug-resistant BLNAR H. influenzae. Copyright © 2016 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.