Ciszewski, Marcin; Czekaj, Tomasz; Szewczyk, Eligia Maria
This article presents the problem of evolutionary changes of zoonotic pathogens responsible for human diseases. Everyone is exposed to the risk of zoonotic infection, particularly employees having direct contact with animals, i.e. veterinarians, breeders, butchers and workers of animal products' processing industry. The article focuses on pathogens monitored by the European Centre for Disease Prevention and Control (ECDC), which has been collecting statistical data on zoonoses from all European Union countries for 19 years and publishing collected data in annual epidemiological reports. Currently, the most important 11 pathogens responsible for causing human zoonotic diseases are being monitored, of which seven are bacteria: Salmonella spp., Campylobacter spp., Listeria monocytogenes, Mycobacterium bovis, Brucella spp., Coxiella burnetti and Verotoxin-producing E. coli (VTEC)/Shiga-like toxin producing E. coli (STEC). As particularly important are considered foodborne pathogens. The article also includes new emerging zoonotic bacteria, which are not currently monitored by ECDC but might pose a serious epidemiological problem in a foreseeable future: Streptococcus iniae, S. suis, S. dysgalactiae and staphylococci: Staphylococcus intermedius, S. pseudintermedius. Those species have just crossed the animal-human interspecies barrier. The exact mechanism of this phenomenon remains unknown, it is connected, however, with genetic variability, capability to survive in changing environment. These abilities derive from DNA rearrangement and horizontal gene transfer between bacterial cells. Substantial increase in the number of scientific publications on this subject, observed over the last few years, illustrates the importance of the problem.
Horton, Katherine C.; Wasfy, Momtaz; Samaha, Hamed; Abdel-Rahman, Bassem; Safwat, Sameh; Abdel Fadeel, Moustafa; Mohareb, Emad; Dueger, Erica
Introduction Zoonotic diseases are an important cause of human morbidity and mortality. Animal populations at locations with high risk of transmission of zoonotic pathogens offer an opportunity to study viral and bacterial pathogens of veterinary and public health concern. Methods Blood samples were collected from domestic and imported livestock slaughtered at the Muneeb abattoir in central Egypt in 2009. Samples were collected from cattle (n = 161), buffalo (n = 153), sheep (n = 174), and camels (n = 10). Samples were tested for antibodies against Leptospira spp. by a microscopy agglutination test, Coxiella burnetii by enzyme immunoassay, Brucella spp. by standard tube agglutination, and Rift Valley Fever virus (RVFV), Crimean–Congo hemorrhagic fever virus (CCHFV), sandfly fever Sicilian virus (SFSV), and sandfly fever Naples virus (SFNV) by enzyme-linked immunosorbent assay. Results Antibodies against Leptospira spp. were identified in 64 (40%) cattle, 45 (29%) buffalo, 71 (41%) sheep, and five (50%) camels; antibodies against C. burnetii in six (4%) buffalo, 14 (8%) sheep, and seven (70%) camels; and antibodies against Brucella spp. in 12 (8%) cattle, one (1%) buffalo, seven (4%) sheep, and one (10%) camel. Antibodies against RVFV were detected in two (1%) cattle and five (3%) buffalo, and antibodies against CCHFV in one (1%) cow. No antibodies against SFSV or SFNV were detected in any species. Discussion Results indicate that livestock have been exposed to a number of pathogens, although care must be taken with interpretation. It is not possible to determine whether antibodies against Leptospira spp. and RVFV in cattle and buffalo are due to prior vaccination or natural exposure. Similarly, antibodies identified in animals less than 6 months of age may be maternal antibodies transferred through colostrum rather than evidence of prior exposure. Results provide baseline evidence to indicate that surveillance within animal populations may be a useful tool to
van Samkar, Anusha; Brouwer, Matthijs C; van der Ende, Arie; van de Beek, Diederik
To describe the epidemiology, etiology, clinical characteristics, treatment, outcome, and prevention of zoonotic bacterial meningitis in human adults. We identified 16 zoonotic bacteria causing meningitis in adults. Zoonotic bacterial meningitis is uncommon compared to bacterial meningitis caused by human pathogens, and the incidence has a strong regional distribution. Zoonotic bacterial meningitis is mainly associated with animal contact, consumption of animal products, and an immunocompromised state of the patient. In a high proportion of zoonotic bacterial meningitis cases, CSF analysis showed only a mildly elevated leukocyte count. The recommended antibiotic therapy differs per pathogen, and the overall mortality is low. Zoonotic bacterial meningitis is uncommon but is associated with specific complications. The suspicion should be raised in patients with bacterial meningitis who have recreational or professional contact with animals and in patients living in regions endemic for specific zoonotic pathogens. An immunocompromised state is associated with a worse prognosis. Identification of risk factors and underlying disease is necessary to improve treatment. © 2016 American Academy of Neurology.
Lambertini, Elisabetta; Buchanan, Robert L; Narrod, Clare; Pradhan, Abani K
Recent Salmonella outbreaks associated with dry pet food and treats raised the level of concern for these products as vehicle of pathogen exposure for both pets and their owners. The need to characterize the microbiological and risk profiles of this class of products is currently not supported by sufficient specific data. This systematic review summarizes existing data on the main variables needed to support an ingredients-to-consumer quantitative risk model to (1) describe the microbial ecology of bacterial pathogens in the dry pet food production chain, (2) estimate pet exposure to pathogens through dry food consumption, and (3) assess human exposure and illness incidence due to contact with pet food and pets in the household. Risk models populated with the data here summarized will provide a tool to quantitatively address the emerging public health concerns associated with pet food and the effectiveness of mitigation measures. Results of such models can provide a basis for improvements in production processes, risk communication to consumers, and regulatory action.
Haack, Sheridan K; Duris, Joseph W; Kolpin, Dana W; Focazio, Michael J; Meyer, Michael T; Johnson, Heather E; Oster, Ryan J; Foreman, William T
Animal waste, stream water, and streambed sediment from 19 small (<32km(2)) watersheds in 12U.S. states having either no major animal agriculture (control, n=4), or predominantly beef (n=4), dairy (n=3), swine (n=5), or poultry (n=3) were tested for: 1) cholesterol, coprostanol, estrone, and fecal indicator bacteria (FIB) concentrations, and 2) shiga-toxin producing and enterotoxigenic Escherichia coli, Salmonella, Campylobacter, and pathogenic and vancomycin-resistant enterococci by polymerase chain reaction (PCR) on enrichments, and/or direct quantitative PCR. Pathogen genes were most frequently detected in dairy wastes, followed by beef, swine and poultry wastes in that order; there was only one detection of an animal-source-specific pathogen gene (stx1) in any water or sediment sample in any control watershed. Post-rainfall pathogen gene numbers in stream water were significantly correlated with FIB, cholesterol and coprostanol concentrations, and were most highly correlated in dairy watershed samples collected from 3 different states. Although collected across multiple states and ecoregions, animal-waste gene profiles were distinctive via discriminant analysis. Stream water gene profiles could also be discriminated by the watershed animal type. Although pathogen genes were not abundant in stream water or streambed samples, PCR on enrichments indicated that many genes were from viable organisms, including several (shiga-toxin producing or enterotoxigenic E. coli, Salmonella, vancomycin-resistant enterococci) that could potentially affect either human or animal health. Pathogen gene numbers and types in stream water samples were influenced most by animal type, by local factors such as whether animals had stream access, and by the amount of local rainfall, and not by studied watershed soil or physical characteristics. Our results indicated that stream water in small agricultural U.S. watersheds was susceptible to pathogen gene inputs under typical agricultural
Haack, Sheridan K.; Duris, Joseph W.; Kolpin, Dana W.; Focazio, Michael J.; Meyer, Michael T.; Johnson, Heather E.; Oster, Ryan J.; Foreman, William T.
Animal waste, stream water, and streambed sediment from 19 small (< 32 km2) watersheds in 12 U.S. states having either no major animal agriculture (control, n = 4), or predominantly beef (n = 4), dairy (n = 3), swine (n = 5), or poultry (n = 3) were tested for: 1) cholesterol, coprostanol, estrone, and fecal indicator bacteria (FIB) concentrations, and 2) shiga-toxin producing and enterotoxigenic Escherichia coli, Salmonella, Campylobacter, and pathogenic and vancomycin-resistant enterococci by polymerase chain reaction (PCR) on enrichments, and/or direct quantitative PCR. Pathogen genes were most frequently detected in dairy wastes, followed by beef, swine and poultry wastes in that order; there was only one detection of an animal-source-specific pathogen gene (stx1) in any water or sediment sample in any control watershed. Post-rainfall pathogen gene numbers in stream water were significantly correlated with FIB, cholesterol and coprostanol concentrations, and were most highly correlated in dairy watershed samples collected from 3 different states. Although collected across multiple states and ecoregions, animal-waste gene profiles were distinctive via discriminant analysis. Stream water gene profiles could also be discriminated by the watershed animal type. Although pathogen genes were not abundant in stream water or streambed samples, PCR on enrichments indicated that many genes were from viable organisms, including several (shiga-toxin producing or enterotoxigenic E. coli, Salmonella, vancomycin-resistant enterococci) that could potentially affect either human or animal health. Pathogen gene numbers and types in stream water samples were influenced most by animal type, by local factors such as whether animals had stream access, and by the amount of local rainfall, and not by studied watershed soil or physical characteristics. Our results indicated that stream water in small agricultural U.S. watersheds was susceptible to pathogen gene inputs under
Schmidt, Sabrina; Essbauer, Sandra S.; Mayer-Scholl, Anne; Poppert, Sven; Schmidt-Chanasit, Jonas; Klempa, Boris; Henning, Klaus; Schares, Gereon; Groschup, Martin H.; Spitzenberger, Friederike; Richter, Dania; Heckel, Gerald
Abstract Rodents are important reservoirs for a large number of zoonotic pathogens. We examined the occurrence of 11 viral, bacterial, and parasitic agents in rodent populations in Austria, including three different hantaviruses, lymphocytic choriomeningitis virus, orthopox virus, Leptospira spp., Borrelia spp., Rickettsia spp., Bartonella spp., Coxiella burnetii, and Toxoplasma gondii. In 2008, 110 rodents of four species (40 Clethrionomys glareolus, 29 Apodemus flavicollis, 26 Apodemus sylvaticus, and 15 Microtus arvalis) were trapped at two rural sites in Lower Austria. Chest cavity fluid and samples of lung, spleen, kidney, liver, brain, and ear pinna skin were collected. We screened selected tissue samples for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, Leptospira, Borrelia, Rickettsia, Bartonella spp., C. burnetii, and T. gondii by RT-PCR/PCR and detected nucleic acids of Tula hantavirus, Leptospira spp., Borrelia afzelii, Rickettsia spp., and different Bartonella species. Serological investigations were performed for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, and Rickettsia spp. Here, Dobrava-Belgrade hantavirus-, Tula hantavirus-, lymphocytic choriomeningitis virus-, orthopox virus-, and rickettsia-specific antibodies were demonstrated. Puumala hantavirus, C. burnetii, and T. gondii were neither detected by RT-PCR/PCR nor by serological methods. In addition, multiple infections with up to three pathogens were shown in nine animals of three rodent species from different trapping sites. In conclusion, these results show that rodents in Austria may host multiple zoonotic pathogens. Our observation raises important questions regarding the interactions of different pathogens in the host, the countermeasures of the host's immune system, the impact of the host–pathogen interaction on the fitness of the host, and the spread of infectious agents among wild rodents and from those to other animals or humans. PMID
Schmidt, Sabrina; Essbauer, Sandra S; Mayer-Scholl, Anne; Poppert, Sven; Schmidt-Chanasit, Jonas; Klempa, Boris; Henning, Klaus; Schares, Gereon; Groschup, Martin H; Spitzenberger, Friederike; Richter, Dania; Heckel, Gerald; Ulrich, Rainer G
Rodents are important reservoirs for a large number of zoonotic pathogens. We examined the occurrence of 11 viral, bacterial, and parasitic agents in rodent populations in Austria, including three different hantaviruses, lymphocytic choriomeningitis virus, orthopox virus, Leptospira spp., Borrelia spp., Rickettsia spp., Bartonella spp., Coxiella burnetii, and Toxoplasma gondii. In 2008, 110 rodents of four species (40 Clethrionomys glareolus, 29 Apodemus flavicollis, 26 Apodemus sylvaticus, and 15 Microtus arvalis) were trapped at two rural sites in Lower Austria. Chest cavity fluid and samples of lung, spleen, kidney, liver, brain, and ear pinna skin were collected. We screened selected tissue samples for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, Leptospira, Borrelia, Rickettsia, Bartonella spp., C. burnetii, and T. gondii by RT-PCR/PCR and detected nucleic acids of Tula hantavirus, Leptospira spp., Borrelia afzelii, Rickettsia spp., and different Bartonella species. Serological investigations were performed for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, and Rickettsia spp. Here, Dobrava-Belgrade hantavirus-, Tula hantavirus-, lymphocytic choriomeningitis virus-, orthopox virus-, and rickettsia-specific antibodies were demonstrated. Puumala hantavirus, C. burnetii, and T. gondii were neither detected by RT-PCR/PCR nor by serological methods. In addition, multiple infections with up to three pathogens were shown in nine animals of three rodent species from different trapping sites. In conclusion, these results show that rodents in Austria may host multiple zoonotic pathogens. Our observation raises important questions regarding the interactions of different pathogens in the host, the countermeasures of the host's immune system, the impact of the host-pathogen interaction on the fitness of the host, and the spread of infectious agents among wild rodents and from those to other animals or humans.
Bacterial pathogens are examples of classical etiological agents of waterborne disease. While these agents no longer serve as major threats to U.S. water supplies, they are still important pathogens in areas with substandard sanitation and poor water treatment facilities. In th...
Rothenburger, Jamie L; Himsworth, Chelsea H; Nemeth, Nicole M; Pearl, David L; Jardine, Claire M
Knowledge of pathogen ecology, including the impacts of environmental factors on pathogen and host dynamics, is essential for determining the risk that zoonotic pathogens pose to people. This review synthesizes the scientific literature on environmental factors that influence the ecology and epidemiology of zoonotic microparasites (bacteria, viruses and protozoa) in globally invasive urban exploiter wildlife species (i.e., rock doves [Columba livia domestica], European starlings [Sturnus vulgaris], house sparrows [Passer domesticus], Norway rats [Rattus norvegicus], black rats [R. rattus] and house mice [Mus musculus]). Pathogen ecology, including prevalence and pathogen characteristics, is influenced by geographical location, habitat, season and weather. The prevalence of zoonotic pathogens in mice and rats varies markedly over short geographical distances, but tends to be highest in ports, disadvantaged (e.g., low income) and residential areas. Future research should use epidemiological approaches, including random sampling and robust statistical analyses, to evaluate a range of biotic and abiotic environmental factors at spatial scales suitable for host home range sizes. Moving beyond descriptive studies to uncover the causal factors contributing to uneven pathogen distribution among wildlife hosts in urban environments may lead to targeted surveillance and intervention strategies. Application of this knowledge to urban maintenance and planning may reduce the potential impacts of urban wildlife-associated zoonotic diseases on people.
Siembieda, Jennifer L; Miller, Woutrina A; Byrne, Barbara A; Ziccardi, Michael H; Anderson, Nancy; Chouicha, Nadira; Sandrock, Christian E; Johnson, Christine K
To determine types and estimate prevalence of potentially zoonotic enteric pathogens shed by wild animals admitted to either of 2 wildlife hospitals and to characterize distribution of these pathogens and of aerobic bacteria in a hospital environment. Cross-sectional study. Fecal samples from 338 animals in 2 wildlife hospitals and environmental samples from 1 wildlife hospital. Fecal samples were collected within 24 hours of hospital admission. Environmental samples were collected from air and surfaces. Samples were tested for zoonotic pathogens via culture techniques and biochemical analyses. Prevalence of pathogen shedding was compared among species groups, ages, sexes, and seasons. Bacterial counts were determined for environmental samples. Campylobacter spp, Vibrio spp, Salmonella spp, Giardia spp, and Cryptosporidium spp (alone or in combination) were detected in 105 of 338 (31%) fecal samples. Campylobacter spp were isolated only from birds. Juvenile passerines were more likely to shed Campylobacter spp than were adults; prevalence increased among juvenile passerines during summer. Non-O1 serotypes of Vibrio cholerae were isolated from birds; during an oil-spill response, 9 of 10 seabirds screened were shedding this pathogen, which was also detected in environmental samples. Salmonella spp and Giardia spp were isolated from birds and mammals; Cryptosporidium spp were isolated from mammals only. Floors of animal rooms had higher bacterial counts than did floors with only human traffic. Potentially zoonotic enteric pathogens were identified in samples from several species admitted to wildlife hospitals, indicating potential for transmission if prevention is not practiced.
Wilcox, Bruce A; Gubler, Duane J
The incidence and frequency of epidemic transmission of zoonotic diseases, both known and newly recognized, has increased dramatically in the past 30 years. It is thought that this dramatic disease emergence is primarily the result of the social, demographic, and environmental transformation that has occurred globally since World War II. However, the causal linkages have not been elucidated. Investigating emerging zoonotic pathogens as an ecological phenomenon can provide significant insights as to why some of these pathogens have jumped species and caused major epidemics in humans. A review of concepts and theory from biological ecology and of causal factors in disease emergence previously described suggests a general model of global zoonotic disease emergence. The model links demographic and societal factors to land use and land cover change whose associated ecological factors help explain disease emergence. The scale and magnitude of these changes are more significant than those associated with climate change, the effects of which are largely not yet understood. Unfortunately, the complex character and non-linear behavior of the human-natural systems in which host-pathogen systems are embedded makes specific incidences of disease emergence or epidemics inherently difficult to predict. Employing a complex systems analytical approach, however, may show how a few key ecological variables and system properties, including the adaptive capacity of institutions, explains the emergence of infectious diseases and how an integrated, multi-level approach to zoonotic disease control can reduce risk.
Kalthoff, Donata; Globig, Anja; Beer, Martin
Zoonotic agents challenging the world every year afresh are influenza A viruses. In the past, human pandemics caused by influenza A viruses had been occurring periodically. Wild aquatic birds are carriers of the full variety of influenza virus A subtypes, and thus, most probably constitute the natural reservoir of all influenza A viruses. Whereas avian influenza viruses in their natural avian reservoir are generally of low pathogenicity (LPAIV), some have gained virulence by mutation after transmission and adaptation to susceptible gallinaceous poultry. Those so-called highly pathogenic avian influenza viruses (HPAIV) then cause mass die-offs in susceptible birds and lead to tremendous economical losses when poultry is affected. Besides a number of avian influenza virus subtypes that have sporadically infected mammals, the HPAIV H5N1 Asia shows strong zoonotic characteristics and it was transmitted from birds to different mammalian species including humans. Theoretically, pandemic viruses might derive directly from avian influenza viruses or arise after genetic reassortment between viruses of avian and mammalian origin. So far, HPAIV H5N1 already meets two conditions for a pandemic virus: as a new subtype it has been hitherto unseen in the human population and it has infected at least 438 people, and caused severe illness and high lethality in 262 humans to date (August 2009). The acquisition of efficient human-to-human transmission would complete the emergence of a new pandemic virus. Therefore, fighting H5N1 at its source is the prerequisite to reduce pandemic risks posed by this virus. Other influenza viruses regarded as pandemic candidates derive from subtypes H2, H7, and H9 all of which have infected humans in the past. Here, we will give a comprehensive overview on avian influenza viruses in concern to their zoonotic potential. Copyright 2009 Elsevier B.V. All rights reserved.
Bai, Ying; Urushadze, Lela; Osikowicz, Lynn; McKee, Clifton; Kuzmin, Ivan; Kandaurov, Andrei; Babuadze, Giorgi; Natradze, Ioseb; Imnadze, Paata; Kosoy, Michael
Bats are important reservoirs for many zoonotic pathogens. However, no surveys of bacterial pathogens in bats have been performed in the Caucasus region. To understand the occurrence and distribution of bacterial infections in these mammals, 218 bats belonging to eight species collected from four regions of Georgia were examined for Bartonella, Brucella, Leptospira, and Yersinia using molecular approaches. Bartonella DNA was detected in 77 (35%) bats from all eight species and was distributed in all four regions. The prevalence ranged 6-50% per bat species. The Bartonella DNA represented 25 unique genetic variants that clustered into 21 lineages. Brucella DNA was detected in two Miniopterus schreibersii bats and in two Myotis blythii bats, all of which were from Imereti (west-central region). Leptospira DNA was detected in 25 (13%) bats that included four M. schreibersii bats and 21 M. blythii bats collected from two regions. The Leptospira sequences represented five genetic variants with one of them being closely related to the zoonotic pathogen L. interrogans (98.6% genetic identity). No Yersinia DNA was detected in the bats. Mixed infections were observed in several cases. One M. blythii bat and one M. schreibersii bat were co-infected with Bartonella, Brucella, and Leptospira; one M. blythii bat and one M. schreibersii bat were co-infected with Bartonella and Brucella; 15 M. blythii bats and three M. schreibersii bats were co-infected with Bartonella and Leptospira. Our results suggest that bats in Georgia are exposed to multiple bacterial infections. Further studies are needed to evaluate pathogenicity of these agents to bats and their zoonotic potential.
Osikowicz, Lynn; McKee, Clifton; Kuzmin, Ivan; Kandaurov, Andrei; Babuadze, Giorgi; Natradze, Ioseb; Imnadze, Paata; Kosoy, Michael
Bats are important reservoirs for many zoonotic pathogens. However, no surveys of bacterial pathogens in bats have been performed in the Caucasus region. To understand the occurrence and distribution of bacterial infections in these mammals, 218 bats belonging to eight species collected from four regions of Georgia were examined for Bartonella, Brucella, Leptospira, and Yersinia using molecular approaches. Bartonella DNA was detected in 77 (35%) bats from all eight species and was distributed in all four regions. The prevalence ranged 6–50% per bat species. The Bartonella DNA represented 25 unique genetic variants that clustered into 21 lineages. Brucella DNA was detected in two Miniopterus schreibersii bats and in two Myotis blythii bats, all of which were from Imereti (west-central region). Leptospira DNA was detected in 25 (13%) bats that included four M. schreibersii bats and 21 M. blythii bats collected from two regions. The Leptospira sequences represented five genetic variants with one of them being closely related to the zoonotic pathogen L. interrogans (98.6% genetic identity). No Yersinia DNA was detected in the bats. Mixed infections were observed in several cases. One M. blythii bat and one M. schreibersii bat were co-infected with Bartonella, Brucella, and Leptospira; one M. blythii bat and one M. schreibersii bat were co-infected with Bartonella and Brucella; 15 M. blythii bats and three M. schreibersii bats were co-infected with Bartonella and Leptospira. Our results suggest that bats in Georgia are exposed to multiple bacterial infections. Further studies are needed to evaluate pathogenicity of these agents to bats and their zoonotic potential. PMID:28129398
Menrath, Andrea; Tomuzia, Katharina; Braeunig, Juliane; Appel, Bernd
Preparedness for the decontamination of affected environments, premises, facilities, and products is one prerequisite for an immediate response to an animal disease outbreak. Various information sources provide recommendations on how to proceed in an outbreak situation to eliminate biological contaminants and to stop the spread of the disease. In order to facilitate the identification of the right decontamination strategy, we present an overview of relevant references for a collection of pathogenic agents. The choice of pathogens is based on a survey of lists containing highly pathogenic agents and/or biological agents considered to be potential vehicles for deliberate contamination of food, feed, or farm animals. European legislation and guidelines from national and international institutions were screened to find decontamination protocols for each of the agents. Identified recommendations were evaluated with regard to their area of application, which could be facilities and equipment, wastes, food, and other animal products. The requirements of a disinfectant for large-scale incidents were gathered, and important characteristics (eg, inactivating spectrum, temperature range, toxicity to environment) of the main recommended disinfectants were summarized to assist in the choice of a suitable and efficient approach in a crisis situation induced by a specific high-risk animal or zoonotic pathogen. The literature search revealed numerous relevant recommendations but also legal gaps for certain diseases, such as Q fever or brucellosis, and legal difficulties for the use of recommended disinfectants. A lack of information about effective disinfectants was identified for some agents. PMID:23971795
Frentzel, Hendrik; Menrath, Andrea; Tomuzia, Katharina; Braeunig, Juliane; Appel, Bernd
Preparedness for the decontamination of affected environments, premises, facilities, and products is one prerequisite for an immediate response to an animal disease outbreak. Various information sources provide recommendations on how to proceed in an outbreak situation to eliminate biological contaminants and to stop the spread of the disease. In order to facilitate the identification of the right decontamination strategy, we present an overview of relevant references for a collection of pathogenic agents. The choice of pathogens is based on a survey of lists containing highly pathogenic agents and/or biological agents considered to be potential vehicles for deliberate contamination of food, feed, or farm animals. European legislation and guidelines from national and international institutions were screened to find decontamination protocols for each of the agents. Identified recommendations were evaluated with regard to their area of application, which could be facilities and equipment, wastes, food, and other animal products. The requirements of a disinfectant for large-scale incidents were gathered, and important characteristics (eg, inactivating spectrum, temperature range, toxicity to environment) of the main recommended disinfectants were summarized to assist in the choice of a suitable and efficient approach in a crisis situation induced by a specific high-risk animal or zoonotic pathogen. The literature search revealed numerous relevant recommendations but also legal gaps for certain diseases, such as Q fever or brucellosis, and legal difficulties for the use of recommended disinfectants. A lack of information about effective disinfectants was identified for some agents.
Vouga, M; Greub, G
Since the 1950s, medical communities have been facing with emerging and reemerging infectious diseases, and emerging pathogens are now considered to be a major microbiologic public health threat. In this review, we focus on bacterial emerging diseases and explore factors involved in their emergence as well as future challenges. We identified 26 major emerging and reemerging infectious diseases of bacterial origin; most of them originated either from an animal and are considered to be zoonoses or from water sources. Major contributing factors in the emergence of these bacterial infections are: (1) development of new diagnostic tools, such as improvements in culture methods, development of molecular techniques and implementation of mass spectrometry in microbiology; (2) increase in human exposure to bacterial pathogens as a result of sociodemographic and environmental changes; and (3) emergence of more virulent bacterial strains and opportunistic infections, especially affecting immunocompromised populations. A precise definition of their implications in human disease is challenging and requires the comprehensive integration of microbiological, clinical and epidemiologic aspects as well as the use of experimental models. It is now urgent to allocate financial resources to gather international data to provide a better understanding of the clinical relevance of these waterborne and zoonotic emerging diseases. Copyright © 2015. Published by Elsevier Ltd.
Konicek, Cornelia; Vodrážka, Pavel; Barták, Pavel; Knotek, Zdenek; Hess, Claudia; Račka, Karol; Hess, Michael; Troxler, Salome
To assess the importance of wild birds as a reservoir of zoonotic pathogens in Austria and the Czech Republic, we sampled 1,325 wild birds representing 13 orders, 32 families, and 81 species. The majority belonged to orders Columbiformes (43%), Passeriformes (25%), and to birds of prey: Accipitriformes, Strigiformes, and Falconiformes (15%). We collected cloacal swabs from 1,191 birds for bacterial culture and 1,214 triple swabs (conjunctiva, choana, cloaca) for DNA and RNA isolation. The cloacal swabs were processed by classical bacteriologic methods for isolation of Escherichia coli , Salmonella spp., methicillin-resistant Staphylococcus aureus (MRSA), and thermophilic Campylobacter spp. Nucleic acids isolated from triple swabs were investigated by PCR for West Nile virus, avian influenza viruses, and Chlamydia spp. We also tested tissue samples from 110 fresh carcasses for Mycobacterium spp. by PCR and we cultured fresh droppings from 114 birds for Cryptococcus spp. The most-frequently detected zoonotic bacteria were thermophilic Campylobacter spp. (12.5%) and Chlamydia spp. (10.3%). From 79.2% of the sampled birds we isolated E. coli , while 8.7% and 0.2% of E. coli isolates possessed the virulence genes for intimin (eaeA) and Shiga toxins (stx 1 and stx 2 ), respectively. Salmonella spp. were rarely found in the sampled birds (2.2%), similar to findings of MRSA (0.3%). None of the samples were positive for Cryptococcus neoformans , Mycobacterium spp., avian influenza viruses, or West Nile virus.
Graham, Elizabeth M; Taylor, David J
With the notable exception of Brucella canis, exogenous bacterial pathogens are uncommon causes of reproductive disease in cats and dogs. Most bacterial reproductive infections are endogenous, and predisposing factors for infection are important. This article reviews the etiology, pathogenesis, clinical presentation, diagnosis, treatment, and public health significance of bacterial reproductive pathogens in cats and dogs.
Schwind, Jessica S; Goldstein, Tracey; Thomas, Kate; Mazet, Jonna A K; Smith, Woutrina A
The capacity to conduct zoonotic pathogen surveillance in wildlife is critical for the recognition and identification of emerging health threats. The PREDICT project, a component of United States Agency for International Development's Emerging Pandemic Threats program, has introduced capacity building efforts to increase zoonotic pathogen surveillance in wildlife in global 'hot spot' regions where zoonotic disease emergence is likely to occur. Understanding priorities, challenges, and opportunities from the perspectives of the stakeholders is a key component of any successful capacity building program. A survey was administered to wildlife officials and to PREDICT-implementing in-country project scientists in 16 participating countries in order to identify similarities and differences in perspectives between the groups regarding capacity needs for zoonotic pathogen surveillance in wildlife. Both stakeholder groups identified some human-animal interfaces (i.e. areas of high contact between wildlife and humans with the potential risk for disease transmission), such as hunting and markets, as important for ongoing targeting of wildlife surveillance. Similarly, findings regarding challenges across stakeholder groups showed some agreement in that a lack of sustainable funding across regions was the greatest challenge for conducting wildlife surveillance for zoonotic pathogens (wildlife officials: 96% and project scientists: 81%). However, the opportunity for improving zoonotic pathogen surveillance capacity identified most frequently by wildlife officials as important was increasing communication or coordination among agencies, sectors, or regions (100% of wildlife officials), whereas the most frequent opportunities identified as important by project scientists were increasing human capacity, increasing laboratory capacity, and the growing interest or awareness regarding wildlife disease or surveillance programs (all identified by 69% of project scientists). A One
The objective of this study was to determine the effect of lysozyme and antibiotics on zoonotic pathogen shedding in feces from nursery pigs housed without and with an indirect disease challenge. Two replicates of 600 pigs each were weaned and randomly assigned to one of 24 pens in either a nursery...
Lysozyme is a 1,4-ß-N-acetylmuramidase that has antimicrobial properties. The objective of this study was to determine the effect of lysozyme and antibiotics on zoonotic pathogen shedding in feces in nursery pigs housed without and with an indirect disease challenge. Two replicates of 600 pigs eac...
Zhu, Xing-Quan; Korhonen, Pasi K.; Cai, Huimin; Young, Neil D.; Nejsum, Peter; von Samson-Himmelstjerna, Georg; Boag, Peter R.; Tan, Patrick; Li, Qiye; Min, Jiumeng; Yang, Yulan; Wang, Xiuhua; Fang, Xiaodong; Hall, Ross S.; Hofmann, Andreas; Sternberg, Paul W.; Jex, Aaron R.; Gasser, Robin B.
Toxocara canis is a zoonotic parasite of major socioeconomic importance worldwide. In humans, this nematode causes disease (toxocariasis) mainly in the under-privileged communities in developed and developing countries. Although relatively well studied from clinical and epidemiological perspectives, to date, there has been no global investigation of the molecular biology of this parasite. Here we use next-generation sequencing to produce a draft genome and transcriptome of T. canis to support future biological and biotechnological investigations. This genome is 317 Mb in size, has a repeat content of 13.5% and encodes at least 18,596 protein-coding genes. We study transcription in a larval, as well as adult female and male stages, characterize the parasite’s gene-silencing machinery, explore molecules involved in development or host–parasite interactions and predict intervention targets. The draft genome of T. canis should provide a useful resource for future molecular studies of this and other, related parasites. PMID:25649139
Morassutti, Alessandra Loureiro; Kazacos, Kevin R.
SUMMARY Baylisascaris procyonis, the raccoon roundworm, infects a wide range of vertebrate animals, including humans, in which it causes a particularly severe type of larva migrans. It is an important cause of severe neurologic disease (neural larva migrans [NLM]) but also causes ocular disease (OLM; diffuse unilateral subacute neuroretinitis [DUSN]), visceral larva migrans (VLM), and covert/asymptomatic infections. B. procyonis is common and widespread in raccoons, and there is increasing recognition of human disease, making a clinical consideration of baylisascariasis important. This review provides an update for this disease, especially its clinical relevance and diagnosis, and summarizes the clinical cases of human NLM and VLM known to date. Most diagnosed patients have been young children less than 2 years of age, although the number of older patients diagnosed in recent years has been increasing. The recent development of recombinant antigen-based serodiagnostic assays has aided greatly in the early diagnosis of this infection. Patients recovering with fewer severe sequelae have been reported in recent years, reinforcing the current recommendation that early treatment with albendazole and corticosteroids should be initiated at the earliest suspicion of baylisascariasis. Considering the seriousness of this zoonotic infection, greater public and medical awareness is critical for the prevention and early treatment of human cases. PMID:26960940
Dow, J M; Daniels, M J
Xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. Inspection of the sequence reveals high relatedness to many genes of other pathogens, notably Xanthomonas campestris. Based on this, we suggest that Xylella possesses certain easily testable properties that contribute to pathogenicity. We also present some general considerations for deriving information on pathogenicity from bacterial genomics. Copyright 2000 John Wiley & Sons, Ltd.
RNA viruses, with their high potential for mutation and epidemic spread, are the most common class of pathogens found as new causes of human illness. Despite great advances made in diagnostic technology since the 1950s, the annual rate at which novel virulent viruses have been found has remained at 2-3. Most emerging viruses are zoonoses; they have jumped from mammal or bird hosts to humans. An analysis of virus discovery indicates that the small number of novel viruses discovered annually is an artifact of inadequate surveillance in tropical and subtropical countries, where even established endemic pathogens are often misdiagnosed. Many of the emerging viruses of the future are already infecting humans but remain to be uncovered by a strategy of disease surveillance in selected populations.
Bhat, Meera; Firth, Matthew A.; Williams, Simon H.; Frye, Matthew J.; Simmonds, Peter; Conte, Juliette M.; Ng, James; Garcia, Joel; Bhuva, Nishit P.; Lee, Bohyun; Che, Xiaoyu; Quan, Phenix-Lan; Lipkin, W. Ian
ABSTRACT Norway rats (Rattus norvegicus) are globally distributed and concentrate in urban environments, where they live and feed in closer proximity to human populations than most other mammals. Despite the potential role of rats as reservoirs of zoonotic diseases, the microbial diversity present in urban rat populations remains unexplored. In this study, we used targeted molecular assays to detect known bacterial, viral, and protozoan human pathogens and unbiased high-throughput sequencing to identify novel viruses related to agents of human disease in commensal Norway rats in New York City. We found that these rats are infected with bacterial pathogens known to cause acute or mild gastroenteritis in people, including atypical enteropathogenic Escherichia coli, Clostridium difficile, and Salmonella enterica, as well as infectious agents that have been associated with undifferentiated febrile illnesses, including Bartonella spp., Streptobacillus moniliformis, Leptospira interrogans, and Seoul hantavirus. We also identified a wide range of known and novel viruses from groups that contain important human pathogens, including sapoviruses, cardioviruses, kobuviruses, parechoviruses, rotaviruses, and hepaciviruses. The two novel hepaciviruses discovered in this study replicate in the liver of Norway rats and may have utility in establishing a small animal model of human hepatitis C virus infection. The results of this study demonstrate the diversity of microbes carried by commensal rodent species and highlight the need for improved pathogen surveillance and disease monitoring in urban environments. PMID:25316698
Esteve-Gassent, Maria Dolores; Pérez de León, Adalberto A.; Romero-Salas, Dora; Feria-Arroyo, Teresa P.; Patino, Ramiro; Castro-Arellano, Ivan; Gordillo-Pérez, Guadalupe; Auclair, Allan; Goolsby, John; Rodriguez-Vivas, Roger Ivan; Estrada-Franco, Jose Guillermo
Transboundary zoonotic diseases, several of which are vector borne, can maintain a dynamic focus and have pathogens circulating in geographic regions encircling multiple geopolitical boundaries. Global change is intensifying transboundary problems, including the spatial variation of the risk and incidence of zoonotic diseases. The complexity of these challenges can be greater in areas where rivers delineate international boundaries and encompass transitions between ecozones. The Rio Grande serves as a natural border between the US State of Texas and the Mexican States of Chihuahua, Coahuila, Nuevo León, and Tamaulipas. Not only do millions of people live in this transboundary region, but also a substantial amount of goods and people pass through it everyday. Moreover, it occurs over a region that functions as a corridor for animal migrations, and thus links the Neotropic and Nearctic biogeographic zones, with the latter being a known foci of zoonotic diseases. However, the pathogenic landscape of important zoonotic diseases in the south Texas–Mexico transboundary region remains to be fully understood. An international perspective on the interplay between disease systems, ecosystem processes, land use, and human behaviors is applied here to analyze landscape and spatial features of Venezuelan equine encephalitis, Hantavirus disease, Lyme Borreliosis, Leptospirosis, Bartonellosis, Chagas disease, human Babesiosis, and Leishmaniasis. Surveillance systems following the One Health approach with a regional perspective will help identifying opportunities to mitigate the health burden of those diseases on human and animal populations. It is proposed that the Mexico–US border along the Rio Grande region be viewed as a continuum landscape where zoonotic pathogens circulate regardless of national borders. PMID:25453027
Esteve-Gassent, Maria Dolores; Pérez de León, Adalberto A; Romero-Salas, Dora; Feria-Arroyo, Teresa P; Patino, Ramiro; Castro-Arellano, Ivan; Gordillo-Pérez, Guadalupe; Auclair, Allan; Goolsby, John; Rodriguez-Vivas, Roger Ivan; Estrada-Franco, Jose Guillermo
Transboundary zoonotic diseases, several of which are vector borne, can maintain a dynamic focus and have pathogens circulating in geographic regions encircling multiple geopolitical boundaries. Global change is intensifying transboundary problems, including the spatial variation of the risk and incidence of zoonotic diseases. The complexity of these challenges can be greater in areas where rivers delineate international boundaries and encompass transitions between ecozones. The Rio Grande serves as a natural border between the US State of Texas and the Mexican States of Chihuahua, Coahuila, Nuevo León, and Tamaulipas. Not only do millions of people live in this transboundary region, but also a substantial amount of goods and people pass through it everyday. Moreover, it occurs over a region that functions as a corridor for animal migrations, and thus links the Neotropic and Nearctic biogeographic zones, with the latter being a known foci of zoonotic diseases. However, the pathogenic landscape of important zoonotic diseases in the south Texas-Mexico transboundary region remains to be fully understood. An international perspective on the interplay between disease systems, ecosystem processes, land use, and human behaviors is applied here to analyze landscape and spatial features of Venezuelan equine encephalitis, Hantavirus disease, Lyme Borreliosis, Leptospirosis, Bartonellosis, Chagas disease, human Babesiosis, and Leishmaniasis. Surveillance systems following the One Health approach with a regional perspective will help identifying opportunities to mitigate the health burden of those diseases on human and animal populations. It is proposed that the Mexico-US border along the Rio Grande region be viewed as a continuum landscape where zoonotic pathogens circulate regardless of national borders.
Traversa, Donato; Di Cesare, Angela; Simonato, Giulia; Cassini, Rudi; Merola, Carmine; Diakou, Anastasia; Halos, Lénaïg; Beugnet, Frederic; Frangipane di Regalbono, Antonio
This study investigated the presence of zoonotic parasites and vector-borne pathogens in dogs housed in kennels and shelters from four sites of Italy. A total of 150 adoptable dogs was examined with different microscopic, serological and molecular methods. Overall 129 dogs (86%) were positive for one or more parasites and/or pathogens transmitted by ectoparasites. Forty-eight (32%) were positive for one infection, while 81 (54%) for more than one pathogen. The most common zoonotic helminths recorded were hookworms, roundworms and Capillaria aerophila, followed by mosquito-borne Dirofilaria spp. and Dipylidium caninum. One hundred and thirteen (77.9%), 6 (4.1%) and 2 (1.4%) dogs were positive for Rickettsia spp., Leishmania infantum and Anaplasma spp., respectively. The results show that dogs living in rescue facilities from the studied areas may be infected by many zoonotic internal parasites and vector-borne pathogens, and that control measures should be implemented. Copyright © 2017 Elsevier Ltd. All rights reserved.
Haack, Sheridan K.; Duris, Joseph W.; Kolpin, Dana W.; Fogarty, Lisa R.; Johnson, Heather E.; Gibson, Kristen E.; Focazio, Michael J.; Schwab, Kellogg J.; Hubbard, Laura E.; Foreman, William T.
Manure spills to streams are relatively frequent, but no studies have characterized stream contamination with zoonotic and veterinary pathogens, or fecal chemicals, following a spill. We tested stream water and sediment over 25 days and downstream for 7.6 km for: fecal indicator bacteria (FIB); the fecal indicator chemicals cholesterol and coprostanol; 20 genes for zoonotic and swine-specific bacterial pathogens by presence/absence polymerase chain reaction (PCR) for viable cells; one swine-specific Escherichia coli toxin gene (STII) by quantitative PCR (qPCR); and nine human and animal viruses by qPCR, or reverse-transcriptase qPCR. Twelve days post-spill, and 4.2 km downstream, water concentrations of FIB, cholesterol, and coprostanol were 1-2 orders of magnitude greater than those detected before, or above, the spill, and genes indicating viable zoonotic or swine-infectious Escherichia coli, were detected in water or sediment. STII increased from undetectable before, or above the spill, to 105 copies/100 mL water 12 days post-spill. Thirteen of 14 water (8/9 sediment) samples had viable STII-carrying cells post-spill. Eighteen days post-spill porcine adenovirus and teschovirus were detected 5.6 km downstream. Sediment FIB concentrations (per gram wet weight) were greater than in water, and sediment was a continuous reservoir of genes and chemicals post-spill. Constituent concentrations were much lower, and detections less frequent, in a runoff event (200 days post-spill) following manure application, although the swine-associated STII and stx2e genes were detected. Manure spills are an underappreciated pathway for livestock-derived contaminants to enter streams, with persistent environmental outcomes, and the potential for human and veterinary health consequences.
Abstract Extraintestinal pathogenic Escherichia coli (ExPEC) constitutes ongoing health concerns for women, newborns, elderly, and immunocompromised individuals due to increased numbers of urinary tract infections (UTIs), newborn meningitis, abdominal sepsis, and septicemia. E. coli remains the leading cause of UTIs, with recent investigations reporting the emergence of E. coli as the predominant cause of nosocomial and neonatal sepsis infections. This shift from the traditional Gram-positive bacterial causes of nosocomial and neonatal sepsis infections could be attributed to the use of intrapartum chemoprophylaxis against Gram-positive bacteria and the appearance of antibiotic (ATB) resistance in E. coli. While ExPEC strains cause significant healthcare concerns, these bacteria also infect chickens and cause the poultry industry economic losses due to costs of containment, mortality, and disposal of carcasses. To circumvent ExPEC-related costs, ATBs are commonly used in the poultry industry to prevent/treat microbial infections and promote growth and performance. In an unfortunate linkage, chicken products are suspected to be a source of foodborne ExPEC infections and ATB resistance in humans. Therefore, the emergence of multidrug resistance (MDR) (resistance to three or more classes of antimicrobial agents) among avian E. coli has created major economic and health concerns, affecting both human healthcare and poultry industries. Increased numbers of immunocompromised individuals, including the elderly, coupled with MDR among ExPEC strains, will continue to challenge the treatment of ExPEC infections and likely lead to increased treatment costs. With ongoing complications due to emerging ATB resistance, novel treatment strategies are necessary to control ExPEC infections. Recognizing and treating the zoonotic risk posed by ExPEC would greatly enhance food safety and positively impact human health. PMID:23962019
Transboundary zoonotic diseases, several of which are vector borne, can maintain a dynamic focus and have pathogens circulating in geographic regions encircling multiple geopolitical boundaries. Global change is intensifying transboundary problems, including the spatial variation of the risk and inc...
Segura, Mariela; Zheng, Han; de Greeff, Astrid; Gao, George F; Grenier, Daniel; Jiang, Yongqiang; Lu, Chengping; Maskell, Duncan; Oishi, Kazunori; Okura, Masatoshi; Osawa, Ro; Schultsz, Constance; Schwerk, Christian; Sekizaki, Tsutomu; Smith, Hilde; Srimanote, Potjanee; Takamatsu, Daisuke; Tang, Jiaqi; Tenenbaum, Tobias; Tharavichitkul, Prasit; Hoa, Ngo Thi; Valentin-Weigand, Peter; Wells, Jerry M; Wertheim, Heiman; Zhu, Baoli; Xu, Jianguo; Gottschalk, Marcelo
First International Workshop on Streptococcus suis, Beijing, China, 12-13 August 2013. This second and final chapter of the report on the First International Workshop on Streptococcus suis follows on from Part 1, published in the April 2014, volume 9, issue 4 of Future Microbiology. S. suis is a swine pathogen and a zoonotic agent afflicting people in close contact with infected pigs or pork meat. Although sporadic cases of human infections had been reported worldwide, deadly S. suis outbreaks emerged in Asia. The severity of the disease underscores the lack of knowledge on the virulence and zoonotic evolution of this human-infecting agent. The pathogenesis of the infection, interactions with host cells and new avenues for treatments were among the topics discussed during the First International Workshop on S. suis (China 2013).
Fuchs, Thilo Martin
Cautious optimism has arisen over recent decades with respect to the long struggle against bacteria, viruses, and parasites. This has been offset, however, by a fatal complacency stemming from previous successes such as the development of antimicrobial drugs, the eradication of smallpox, and global immunization programs. Infectious diseases nevertheless remain the world's leading cause of death, killing at least 17 million persons annually . Diarrheal diseases caused by Vibrio cholerae or Shigella dysenteriae kill about 3 million persons every year, most of them young children: Another 4 million die of tuberculosis or tetanus. Outbreaks of diphtheria in Eastern Europe threatens the population with a disease that had previously seemed to be overcome. Efforts to control infectious diseases more comprehensively are undermined not only by socioeconomic conditions but also by the nature of the pathogenic organisms itself; some isolates of Staphylococcus aureus and Enterobacter have become so resistant to drugs by horizontal gene transfer that they are almost untreatable. In addition, the mechanism of genetic variability helps pathogens to evade the human immune system, thus compromising the development of powerful vaccines. Therefore detailed knowledge of the molecular mechanisms of microbial pathogenicity is absolutely necessary to develop new strategies against infectious diseases and thus to lower their impact on human health and social development.
Bitome-Essono, Paul-Yannick; Ollomo, Benjamin; Arnathau, Céline; Durand, Patrick; Mokoudoum, Nancy Diamella; Yacka-Mouele, Lauriane; Okouga, Alain-Prince; Boundenga, Larson; Mve-Ondo, Bertrand; Obame-Nkoghe, Judicaël; Mbehang-Nguema, Philippe; Njiokou, Flobert; Makanga, Boris; Wattier, Rémi; Ayala, Diego; Ayala, Francisco J; Renaud, Francois; Rougeron, Virginie; Bretagnolle, Francois; Prugnolle, Franck; Paupy, Christophe
About 60% of emerging infectious diseases in humans are of zoonotic origin. Their increasing number requires the development of new methods for early detection and monitoring of infectious agents in wildlife. Here, we investigated whether blood meals from hematophagous flies could be used to identify the infectious agents circulating in wild vertebrates. To this aim, 1230 blood-engorged flies were caught in the forests of Gabon. Identified blood meals (30%) were from 20 vertebrate species including mammals, birds and reptiles. Among them, 9% were infected by different extant malaria parasites among which some belonged to known parasite species, others to new parasite species or to parasite lineages for which only the vector was known. This study demonstrates that using hematophagous flies as ‘flying syringes’ constitutes an interesting approach to investigate blood-borne pathogen diversity in wild vertebrates and could be used as an early detection tool of zoonotic pathogens. DOI: http://dx.doi.org/10.7554/eLife.22069.001 PMID:28347401
Artois, M; Blancou, J; Dupeyroux, O; Gilot-Fromont, E
Wildlife may harbour infectious pathogens that are of zoonotic concern. However, culling such reservoir populations to mitigate or control the transmission of these pathogens to humans has proved disappointingly inefficient. Alternatives are still in an experimental stage of development. They include vaccination, medication, contraception and environmental manipulation, including fencing and biosecurity measures. This review examines the general concepts involved in the control of wildlife diseases and presents relevant case studies. Since wildlife disease control inevitably involves interfering with wildlife ecology, this is a complex goal whose attempts at realisation should be supervised by a scientific organisation. Most approaches within natural ecosystems should first be carefully tested in trials that are progressively extended to a larger scale. Finally, all measures that aim to prevent infection in humans (such as personal hygiene or vaccination) or that encourage us to avoid infectious contacts with wildlife should be recommended.
Skånseng, Beate; Trosvik, Pål; Zimonja, Monika; Johnsen, Gro; Bjerrum, Lotte; Pedersen, Karl; Wallin, Nina; Rudi, Knut
A major bottleneck in understanding zoonotic pathogens has been the analysis of pathogen co-infection dynamics. We have addressed this challenge using a novel direct sequencing approach for pathogen quantification in mixed infections. The major zoonotic food-borne pathogen Campylobacter jejuni, with an important reservoir in the gastrointestinal (GI) tract of chickens, was used as a model. We investigated the co-colonisation dynamics of seven C. jejuni strains in a chicken GI infection trial. The seven strains were isolated from an epidemiological study showing multiple strain infections at the farm level. We analysed time-series data, following the Campylobacter colonisation, as well as the dominant background flora of chickens. Data were collected from the infection at day 16 until the last sampling point at day 36. Chickens with two different background floras were studied, mature (treated with Broilact, which is a product consisting of bacteria from the intestinal flora of healthy hens) and spontaneous. The two treatments resulted in completely different background floras, yet similar Campylobacter colonisation patterns were detected in both groups. This suggests that it is the chicken host and not the background flora that is important in determining the Campylobacter colonisation pattern. Our results showed that mainly two of the seven C. jejuni strains dominated the Campylobacter flora in the chickens, with a shift of the dominating strain during the infection period. We propose a model in which multiple C. jejuni strains can colonise a single host, with the dominant strains being replaced as a consequence of strain-specific immune responses. This model represents a new understanding of C. jejuni epidemiology, with future implications for the development of novel intervention strategies. PMID:18020703
Singh, B B; Gajadhar, A A
Evolving land use practices have led to an increase in interactions at the human/wildlife interface. The presence and poor knowledge of zoonotic pathogens in India's wildlife and the occurrence of enormous human populations interfacing with, and critically linked to, forest ecosystems warrant attention. Factors such as diverse migratory bird populations, climate change, expanding human population and shrinking wildlife habitats play a significant role in the emergence and re-emergence of zoonotic pathogens from India's wildlife. The introduction of a novel Kyasanur forest disease virus (family flaviviridae) into human populations in 1957 and subsequent occurrence of seasonal outbreaks illustrate the key role that India's wild animals play in the emergence and reemergence of zoonotic pathogens. Other high priority zoonotic diseases of wildlife origin which could affect both livestock and humans include influenza, Nipah, Japanese encephalitis, rabies, plague, leptospirosis, anthrax and leishmaniasis. Continuous monitoring of India's extensively diverse and dispersed wildlife is challenging, but their use as indicators should facilitate efficient and rapid disease-outbreak response across the region and occasionally the globe. Defining and prioritizing research on zoonotic pathogens in wildlife are essential, particularly in a multidisciplinary one-world one-health approach which includes human and veterinary medical studies at the wildlife-livestock-human interfaces. This review indicates that wild animals play an important role in the emergence and re-emergence of zoonotic pathogens and provides brief summaries of the zoonotic diseases that have occurred in wild animals in India. Copyright © 2014 Elsevier B.V. All rights reserved.
Sterk, Ankie; de Roda Husman, Ana Maria; Stergiadi, Maria; de Nijs, Ton; Schijven, Jack
Several studies have shown a correlation between rainfall and waterborne disease outbreaks. One of the mechanisms whereby rainfall may cause outbreaks is through an increase in runoff of animal faeces from fields to surface waters. Faeces originating from wildlife, domestic animals or manure-fertilized fields, is considered an important source of zoonotic pathogens to which people may be exposed by water recreation or drinking-water consumption. Climate changes affect runoff because of increasing winter precipitation and more extreme precipitation events, as well as changes in evaporation. Furthermore, drier summers are leading to longer periods of high soil moisture deficits, increasing the hydrophobicity of soil and consequently changing infiltration capacities. A conceptual model is designed to describe the impacts of climate changes on the terrestrial and aquatic ecosystems, which are both directly and indirectly affecting pathogen loads in the environment and subsequent public health risks. One of the major outcomes was the lack of quantitative data and limited qualitative analyses of impacts of climate changes on pathogen runoff. Quantifying the processes by which micro-organisms are transported from fields to waters is important to be able to estimate such impacts to enable targeted implementation of effective intervention measures. A quantitative model using Mathematica software will be developed to estimate concentrations of pathogens originating from overland flow during runoff events. Different input sources will be included by applying different land-use scenarios, including point source faecal pollution from dairy cows and geese and diffuse source pollution by fertilization. Zoonotic pathogens, i.e. Cryptosporidium and Campylobacter, were selected based on transport properties, faecal loads and disease burden. Transport and survival rates of these pathogens are determined including effects of changes in precipitation but also temperature induced
Moran, Nancy A
When bacterial lineages make the transition from free-living or facultatively parasitic life cycles to permanent associations with hosts, they undergo a major loss of genes and DNA. Complete genome sequences are providing an understanding of how extreme genome reduction affects evolutionary directions and metabolic capabilities of obligate pathogens and symbionts.
Didelot, Xavier; Walker, A. Sarah; Peto, Tim E.; Crook, Derrick W.; Wilson, Daniel J.
Whole genome sequencing has opened the way to investigating the dynamics and genomic evolution of bacterial pathogens during colonization and infection of humans. The application of this technology to the longitudinal study of adaptation in the infected host — in particular, the evolution of drug resistance and host adaptation in patients chronically infected with opportunistic pathogens — has revealed remarkable patterns of convergent evolution, pointing to an inherent repeatability of evolution. In this Review, we describe how these studies have advanced our understanding of the mechanisms and principles of within-host genome evolution, and we consider the consequences of findings such as a potent adaptive potential for pathogenicity. Finally, we discuss the possibility that genomics may be used in the future to predict the clinical progression of bacterial infections, and to suggest the best treatment option. PMID:26806595
Didelot, Xavier; Walker, A Sarah; Peto, Tim E; Crook, Derrick W; Wilson, Daniel J
Whole-genome sequencing has opened the way for investigating the dynamics and genomic evolution of bacterial pathogens during the colonization and infection of humans. The application of this technology to the longitudinal study of adaptation in an infected host--in particular, the evolution of drug resistance and host adaptation in patients who are chronically infected with opportunistic pathogens--has revealed remarkable patterns of convergent evolution, suggestive of an inherent repeatability of evolution. In this Review, we describe how these studies have advanced our understanding of the mechanisms and principles of within-host genome evolution, and we consider the consequences of findings such as a potent adaptive potential for pathogenicity. Finally, we discuss the possibility that genomics may be used in the future to predict the clinical progression of bacterial infections and to suggest the best option for treatment.
Carnero, A M; Kitayama, K; Diaz, D A; Garvich, M; Angulo, N; Cama, V A; Gilman, R H; Bayer, A M
Interspecies transmission of pathogens is an unfrequent but naturally occurring event and human activities may favour opportunities not previously reported. Reassortment of zoonotic pathogens like influenza A virus can result from these activities. Recently, swine and birds have played a central role as "mixing vessels" for epidemic and pandemic events related to strains like H1N1 and H5N1. Unsafe practices in poultry markets and swine farms can lead to interspecies transmission, favouring the emergence of novel strains. Thus, understanding practices that lead to interspecies interactions is crucial. This qualitative study aimed to evaluate poultry processing practices in formal and informal markets and the use of leftovers by swine farmers in three Peruvian cities: Lima (capital), Tumbes (coastal) and Tarapoto (jungle). We conducted 80 direct observations at formal and informal markets and interviewed 15 swine farmers. Processors slaughter and pluck chickens and vendors and/or processors eviscerate chickens. Food safety and hygiene practices were suboptimal or absent, although some heterogeneity was observed between cities and chicken vendors versus processors. Both vendors (76%) and processors (100%) sold the chicken viscera leftovers to swine farmers, representing the main source of chicken viscera for swine farms (53%). Swine farmers fed the chicken viscera to their swine. Chicken viscera cooking times varied widely and were insufficient in some cases. Non-abattoired poultry leads to the sale of poultry leftovers to small-scale swine farms, resulting in indirect but frequent interspecies contacts that can lead to interspecies transmission of bacterial pathogens or the reassortment of influenza A viruses. These interactions are exacerbated by suboptimal safety and hygiene conditions. People involved in these activities constitute an at-risk population who could play a central role in preventing the transmission of pathogens between species. Educational
Brown, V R; Bowen, R A; Bosco-Lauth, A M
The natural fecundity of suids, great ability to adapt to new habitats and desire for local hunting opportunities leading to translocation of feral pigs to regions where they are not yet established have all been instrumental in the home range expansion of feral swine. Feral swine populations in the United States continue to expand, wreaking havoc on agricultural lands, further compromising threatened and endangered species, and posing a microbiological threat to humans, domestic livestock and companion animals. This manuscript thoroughly reviews zoonotic diseases of concern including brucellosis, bovine tuberculosis, leptospirosis, enteric pathogens, both Salmonella spp. and shiga toxin-producing Escherichia coli, and hepatitis E. These pathogens are not a comprehensive list of microbes that are capable of infecting both humans and feral swine, but rather have been selected as they are known to infect US feral swine, direct transmission between wild suids and humans has previously been documented, or they have been shown to be readily transmitted during processing or consumption of feral swine pork. Humans that interact directly or indirectly with feral swine are at much higher risk for the development of a number of zoonotic pathogens. Numerous case reports document transmission events from feral swine and wild boar to humans, and the resulting diseases may be mild and self-limiting, chronic or fatal. Individuals that interact with feral swine should take preventative measures to minimize the risk of disease transmission and all meat should be thoroughly cooked. Additionally, public health campaigns to increase knowledge of the risks associated with feral swine are imperative. © 2018 Blackwell Verlag GmbH.
Quiner, C. A.; Nakazawa, Y.
Emerging and understudied pathogens often lack information that most commonly used analytical tools require, such as negative controls or baseline data making public health control of emerging pathogens challenging. In lieu of opportunities to collect more data from larger outbreaks or formal epidemiological studies, new analytical strategies, merging case data with publically available datasets, can be used to understand transmission patterns and drivers of disease emergence. Zoonotic infections with Vaccinia virus (VACV) were first reported in Brazil in 1999, VACV is an emerging zoonotic Orthopoxvirus, which primarily infects dairy cattle and farmers in close contact with infected cows. Prospective studies of emerging pathogens could provide critical data that would inform public health planning and response to outbreaks. By using the location of 87-recorded outbreaks and publicly available bioclimatic data we demonstrate one such approach. Using an Ecological Niche Model (ENM), we identify the environmental conditions under which VACV outbreaks have occurred, and determine additional locations in two affected South American countries that may be susceptible to transmission. Further, we show how suitability for the virus responds to different levels of various environmental factors and highlight the most important climatic factors in determining its transmission. The final ENM predicted all areas where Brazilian outbreaks occurred, two out of five Colombian outbreaks and identified new regions within Brazil that are suitable for transmission based on bioclimatic factors. Further, the most important factors in determining transmission suitability are precipitation of the wettest quarter, annual precipitation, mean temperature of the coldest quarter and mean diurnal range. The analyses here provide a means by which to study patterns of an emerging infectious disease, and regions that are potentially at risk for it, in spite of the paucity of critical data. Policy
Asrat, Seblewongel; de Jesús, Dennise A; Hempstead, Andrew D; Ramabhadran, Vinay; Isberg, Ralph R
Pathogens use a vast number of strategies to alter host membrane dynamics. Targeting the host membrane machinery is important for the survival and pathogenesis of several extracellular, vacuolar, and cytosolic bacteria. Membrane manipulation promotes bacterial replication while suppressing host responses, allowing the bacterium to thrive in a hostile environment. This review provides a comprehensive summary of various strategies used by both extracellular and intracellular bacteria to hijack host membrane trafficking machinery. We start with mechanisms used by bacteria to alter the plasma membrane, delve into the hijacking of various vesicle trafficking pathways, and conclude by summarizing bacterial adaptation to host immune responses. Understanding bacterial manipulation of host membrane trafficking provides insights into bacterial pathogenesis and uncovers the molecular mechanisms behind various processes within a eukaryotic cell.
SUMMARY Cell-cell communication, or quorum sensing, is a widespread phenomenon in bacteria that is used to coordinate gene expression among local populations. Its use by bacterial pathogens to regulate genes that promote invasion, defense, and spread has been particularly well documented. With the ongoing emergence of antibiotic-resistant pathogens, there is a current need for development of alternative therapeutic strategies. An antivirulence approach by which quorum sensing is impeded has caught on as a viable means to manipulate bacterial processes, especially pathogenic traits that are harmful to human and animal health and agricultural productivity. The identification and development of chemical compounds and enzymes that facilitate quorum-sensing inhibition (QSI) by targeting signaling molecules, signal biogenesis, or signal detection are reviewed here. Overall, the evidence suggests that QSI therapy may be efficacious against some, but not necessarily all, bacterial pathogens, and several failures and ongoing concerns that may steer future studies in productive directions are discussed. Nevertheless, various QSI successes have rightfully perpetuated excitement surrounding new potential therapies, and this review highlights promising QSI leads in disrupting pathogenesis in both plants and animals. PMID:23471618
Pedersen, Kerri; Bauer, Nathan E; Rodgers, Sandra; Bazan, Luis R; Mesenbrink, Brian T; Gidlewski, Thomas
The zoonotic risk posed to employees by slaughtering feral swine (Sus scrofa) at two abattoirs in Texas was assessed by testing feral swine serum samples for exposure to influenza A virus, Leptospira, Trichinella spiralis, and Toxoplasma gondii. Blood was collected from a total of 376 feral swine between the two facilities during six separate collection periods in 2015. Antibodies to one or more serovars of Leptospira were identified in 48.9% of feral swine tested, with Bratislava and Pomona as the most commonly detected serovars, and antibodies to influenza A virus were detected in 14.1% of feral swine. Antibodies to T. gondii and T. spiralis were identified in 9.0 and 3.5%, respectively, of feral swine tested. Our results suggest that abattoir employees should be aware of the potential for exposure to various zoonotic pathogens when slaughtering feral swine, wear appropriate personal protective equipment, and participate in medical monitoring programs to ensure detection and prompt treatment. In addition, consumers of feral swine should cook the meat to the appropriate temperature and wash hands and kitchen surfaces thoroughly after preparing meat.
Nhung, Nguyen Thi; Chansiripornchai, Niwat; Carrique-Mas, Juan J.
Antimicrobial resistance (AMR) is a global health threat, and antimicrobial usage and AMR in animal production is one of its contributing sources. Poultry is one of the most widespread types of meat consumed worldwide. Poultry flocks are often raised under intensive conditions using large amounts of antimicrobials to prevent and to treat disease, as well as for growth promotion. Antimicrobial resistant poultry pathogens may result in treatment failure, leading to economic losses, but also be a source of resistant bacteria/genes (including zoonotic bacteria) that may represent a risk to human health. Here we reviewed data on AMR in 12 poultry pathogens, including avian pathogenic Escherichia coli (APEC), Salmonella Pullorum/Gallinarum, Pasteurella multocida, Avibacterium paragallinarum, Gallibacterium anatis, Ornitobacterium rhinotracheale (ORT), Bordetella avium, Clostridium perfringens, Mycoplasma spp., Erysipelothrix rhusiopathiae, and Riemerella anatipestifer. A number of studies have demonstrated increases in resistance over time for S. Pullorum/Gallinarum, M. gallisepticum, and G. anatis. Among Enterobacteriaceae, APEC isolates displayed considerably higher levels of AMR compared with S. Pullorum/Gallinarum, with prevalence of resistance over >80% for ampicillin, amoxicillin, tetracycline across studies. Among the Gram-negative, non-Enterobacteriaceae pathogens, ORT had the highest levels of phenotypic resistance with median levels of AMR against co-trimoxazole, enrofloxacin, gentamicin, amoxicillin, and ceftiofur all exceeding 50%. In contrast, levels of resistance among P. multocida isolates were less than 20% for all antimicrobials. The study highlights considerable disparities in methodologies, as well as in criteria for phenotypic antimicrobial susceptibility testing and result interpretation. It is necessary to increase efforts to harmonize testing practices, and to promote free access to data on AMR in order to improve treatment guidelines as well as to
Mohammed, Kamiran Abdulrahman; Arabacı, Muhammed; Önalan, Şükrü
The aim of this study was to determine the zoonotic bacteria in carp farms in Duhok region of the Northern Iraq. Carp is the main fish species cultured in the Duhok region. The most common zoonotic bacteria generally seen in carp farms are Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus iniae. Samples were collected from 20 carp farms in the Duhok Region of the Northern Iraq. Six carp samples were collected from each carp farm. Head kidney tissue samples and intestine tissue samples were collected from each carp sample. Than head kidney and intestine tissue samples were pooled. The total bacterial DNA extraction from the pooled each 20 head kidney tissue samples and pooled each 20 intestinal tissue samples. Primers for pathogens were originally designed from 16S Ribosomal gene region. Zoonotic bacteria were scanned in all tissue samples by absent / present analysis in the RT-PCR. After RT-PCR, Capillary gel electrophoresis bands were used for the confirmation of the size of amplicon which was planned during primer designing stage. As a result, one sample was positive in respect to Aeromonas hydrophila, from intestine and one carp farm was positive in respect to Pseudomonas fluorescens from intestine and two carp farms were positive in respect to Streptococcus iniae. Totally 17 of 20 carp farms were negative in respect to the zoonotic bacteria. In conclusion the zoonotic bacteria were very low (15 %) in carp farms from the Duhok Region in the Northern Iraq. Only in one Carp farms, both Aeromonas hydrophila and Pseudomonas fluorescens were positive. Also Streptococcus inia were positive in two carp farms.
Ibraheem, Azad Saber; Önalan, Şükrü; Arabacı, Muhammed
The aim of this study was to determine the zoonotic bacteria in carp farms in the Northern Iraq-Erbil region. Carp is the main fish species cultured in Erbil region. The most common zoonotic bacteria generally seen in carp farms are Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus iniae. Samples were collected from 25 carp farms in the Northern Iraq-Erbil region. Six carp samples were collected from each carp farm. Head kidney and intestine tissue samples were collected from each carp sample. Then head kidney and intestine tissue samples were pooled separately from each carp farm. Total bacterial DNA had been extracted from the 25 pooled head kidney and 25 intestinal tissue samples. The pathogen Primers were originally designed from 16S RNA gene region. Zoonotic bacteria were scanned in all tissue samples with absent/present analysis by RT-PCR. Furthermore, the capillary gel electrophoresis bands were used for confirmation of amplicon size which was planned during primer designing stage. As a result, thirteen carp farms were positive in the respect to Aeromonas hydrophila, eight carp farms were positive from head kidney and six carp farms were positive from the intestine, only one carp farm was positive from both head kidney and the intestine tissue samples. In the respect to Streptococcus iniae, four carp farms were positive from head kidney and two carp farms were positive from the intestine. Only one carp farm was positive in the respect to Pseudomonas fluorescens from the intestine. Totally, 9 of 25 carp farms were cleared (negative) the zoonotic bacteria. In conclusion, the zoonotic bacteria were high (64 %) in carp farms in the Northern Iraq-Erbil region.
Reasoner, Donald J.
Presents a literature review of bacterial pathogens that are related to water pollution, covering publications from 1976-77. This review includes: (1) bacterial pathogens in animals; and (2) detection and identification of waterborne bacterial pathogens. A list of 129 references is also presented. (HM)
Olivares, Jorge; Bernardini, Alejandra; Garcia-Leon, Guillermo; Corona, Fernando; B. Sanchez, Maria; Martinez, Jose L.
Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyze recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice. PMID:23641241
Olivares, Jorge; Bernardini, Alejandra; Garcia-Leon, Guillermo; Corona, Fernando; B Sanchez, Maria; Martinez, Jose L
Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyze recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice.
Enterohaemorrhagic Escherichia Coli (EHEC) is a zoonotic pathogen known to be potentially lethal in humans. Its main animal reservoir is ruminants, specifically cattle, and yearly outbreaks occur worldwide with the most prevalent serotype being EHEC O157:H7. Most virulence factors of EHEC O157, incl...
Enterohaemorrhagic E. coli 0157 is a zoonotic pathogen for which colonisation of cattle and virulence in humans is associated with the expression of multiple horizontally acquired genes, the majority present in active or cryptic prophages. Our understanding of the evolution and phylogeny of E. coli ...
urinalis) is cause for concern, as it highlights the possibility for continued acquisition of human virulence factors for this emerging zoonotic pathogen. PMID:23244770
Rozental, Tatiana; Ferreira, Michelle Santos; Guterres, Alexandro; Mares-Guia, Maria Angélica; Teixeira, Bernardo R; Gonçalves, Jonathan; Bonvicino, Cibele Rodrigues; D'Andrea, Paulo Sergio; de Lemos, Elba Regina Sampaio
Zoonotic pathogens comprise a significant and increasing fraction of all emerging and re-emerging infectious diseases that plague humans. Identifying host species is one of the keys to controlling emerging infectious diseases. From March 2007 until April 2012, we collected a total of 131 wild rodents in eight municipalities of Rio de Janeiro, Brazil. We investigated these rodents for infection with Coxiella burnetii, Bartonella spp. and Rickettsia spp. In total, 22.1% (29/131) of the rodents were infected by at least one pathogen; co-infection was detected in 1.5% (2/131) of rodents. Coxiella burnetii was detected in 4.6% (6/131) of the wild animals, 17.6% of the rodents harbored Bartonella spp. No cases of Rickettsia were identified. Bartonella doshiae and Bartonella vinsonii were the species found on the wild mammals. This report is the first to note C. burnetii, B. doshiae and B. vinsonii natural infections in Atlantic Forest wild rodents in Brazil. Our work highlights the potential risk of transmission to humans, since most of the infected specimens belong to generalist species that live near human dwellings. Copyright © 2017 Elsevier B.V. All rights reserved.
Chacón-Díaz, Carlos; Altamirano-Silva, Pamela; González-Espinoza, Gabriela; Medina, María-Concepción; Alfaro-Alarcón, Alejandro; Bouza-Mora, Laura; Jiménez-Rojas, César; Wong, Melissa; Barquero-Calvo, Elías; Rojas, Norman; Guzmán-Verri, Caterina
Canine brucellosis caused by Brucella canis is a disease of dogs and a zoonotic risk. B. canis harbors most of the virulence determinants defined for the genus, but its pathogenic strategy remains unclear since it has not been demonstrated that this natural rough bacterium is an intracellular pathogen. Studies of B. canis outbreaks in kennel facilities indicated that infected dogs displaying clinical signs did not present hematological alterations. A virulent B. canis strain isolated from those outbreaks readily replicated in different organs of mice for a protracted period. However, the levels of tumor necrosis factor alpha, interleukin-6 (IL-6), and IL-12 in serum were close to background levels. Furthermore, B. canis induced lower levels of gamma interferon, less inflammation of the spleen, and a reduced number of granulomas in the liver in mice than did B. abortus. When the interaction of B. canis with cells was studied ex vivo, two patterns were observed, a predominant scattered cell-associated pattern of nonviable bacteria and an infrequent intracellular replicative pattern of viable bacteria in a perinuclear location. The second pattern, responsible for the increase in intracellular multiplication, was dependent on the type IV secretion system VirB and was seen only if the inoculum used for cell infections was in early exponential phase. Intracellular replicative B. canis followed an intracellular trafficking route undistinguishable from that of B. abortus. Although B. canis induces a lower proinflammatory response and has a stealthier replication cycle, it still displays the pathogenic properties of the genus and the ability to persist in infected organs based on the ability to multiply intracellularly. PMID:26438796
Feodorova, Valentina A; Sayapina, Lidiya V; Corbel, Michael J; Motin, Vladimir L
In response to the epidemiological situation, live attenuated or killed vaccines against anthrax, brucellosis, cholera, glanders, plague and tularemia were developed and used for immunization of at-risk populations in the Former Soviet Union. Certain of these vaccines have been updated and currently they are used on a selective basis, mainly for high risk occupations, in the Russian Federation. Except for anthrax and cholera these vaccines currently are the only licensed products available for protection against the most dangerous bacterial pathogens. Development of improved formulations and new products is ongoing. PMID:26038506
Fouts, Derrick E.; Matthias, Michael A.; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E.; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L.; Haake, David A.; Haft, Daniel H.; Hartskeerl, Rudy; Ko, Albert I.; Levett, Paul N.; Matsunaga, James; Mechaly, Ariel E.; Monk, Jonathan M.; Nascimento, Ana L. T.; Nelson, Karen E.; Palsson, Bernhard; Peacock, Sharon J.; Picardeau, Mathieu; Ricaldi, Jessica N.; Thaipandungpanit, Janjira; Wunder, Elsio A.; Yang, X. Frank; Zhang, Jun-Jie; Vinetz, Joseph M.
Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade’s refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic
Fouts, Derrick E; Matthias, Michael A; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L; Haake, David A; Haft, Daniel H; Hartskeerl, Rudy; Ko, Albert I; Levett, Paul N; Matsunaga, James; Mechaly, Ariel E; Monk, Jonathan M; Nascimento, Ana L T; Nelson, Karen E; Palsson, Bernhard; Peacock, Sharon J; Picardeau, Mathieu; Ricaldi, Jessica N; Thaipandungpanit, Janjira; Wunder, Elsio A; Yang, X Frank; Zhang, Jun-Jie; Vinetz, Joseph M
Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic
Mtshali, Khethiwe; Khumalo, Zth; Nakao, Ryo; Grab, Dennis J; Sugimoto, Chihiro; Thekisoe, Omm
Ticks carry and transmit a remarkable array of pathogens including bacteria, protozoa and viruses, which may be of veterinary and/or of medical significance. With little to no information regarding the presence of tick-borne zoonotic pathogens or their known vectors in southern Africa, the aim of our study was to screen for Anaplasma phagocytophilum, Borrelia burgdorferi, Coxiella burnetii, Rickettsia species and Ehrlichia ruminantium in ticks collected and identified from ruminants in the Eastern Cape, Free State, KwaZulu-Natal and Mpumalanga Provinces of South Africa. The most abundant tick species identified in this study were Rhipicephalus evertsi evertsi (40%), Rhipicephalus species (35%), Amblyomma hebraeum (10%) and Rhipicephalus decoloratus (14%). A total of 1634 ticks were collected. DNA was extracted, and samples were subjected to PCR amplification and sequencing. The overall infection rates of ticks with the target pathogens in the four Provinces were as follows: A. phagocytophilum, 7%; C. burnetii, 7%; E. ruminantium, 28%; and Rickettsia spp., 27%. The presence of B. burgdorferi could not be confirmed. The findings of this study show that zoonotic pathogens are present in ticks in the studied South African provinces. This information will aid in the epidemiology of tick-borne zoonotic diseases in the country as well as in raising awareness about such diseases in the veterinary, medical and tourism sectors, as they may be the most affected.
Cabral, João P S
Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water-cholera, typhoid fever and bacillary dysentery-is presented, focusing on the biology and ecology of the causal agents and on the diseases' characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.
Cabral, João P. S.
Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water—cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases’ characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters. PMID:21139855
Sutherland, Sara J.; Gray, Jeffrey T.; Menzies, Paula I.; Hook, Sarah E.; Millman, Suzanne T.
The objective of this study was to determine if sheep grazing near riparian areas on pasture in Ontario are an important risk factor for the contamination of water with specific foodborne pathogens. Ten Ontario sheep farms were visited weekly for 12 wk during the summer of 2005. Samples of feces, soil, and water were collected and analyzed for the presence of Escherichia coli O157:H7, Salmonella spp., Campylobacter jejuni and C. coli, and Yersinia enterocolitica, by bacteriological identification and polymerase chain reaction (PCR). The data was analyzed as repeated measures over time using mixed models. No samples were positive for Salmonella, and no samples were confirmed positive for E. coli O157:H7 after PCR. Levels of Campylobacter were highest in the soil, but did not differ between soil where sheep grazed or camped and roadside soil that had never been grazed (P = 0.85). Levels of Yersinia were highest in water samples and were higher in soil where sheep had access (P = 0.01). The prevalence of positive Campylobacter and Yersinia samples were not associated with locations where sheep spent more time (Campylobacter P = 0.46, Yersinia P = 0.99). There was no effect of stocking density on the prevalence of Campylobacter (P = 0.30), but as the stocking density increased the levels of Yersinia increased (P = 0.04). It was concluded that although sheep transmit Yersinia to their environment, pastured sheep flocks are not major risk factors for the transmission of zoonotic pathogens into water. PMID:19436581
Zhang, Qinghua; Dong, Xuehong; Chen, Biao; Zhang, Yonghua; Zu, Yao; Li, Weiming
Vibrio parahaemolyticus is an important aquatic zoonotic pathogen worldwide that causes vibriosis in many marine fish, and sepsis, gastroenteritis and wound infection in humans. However, the pathogenesis of different sources of V. parahaemolyticus is not fully understood. Here, we examined the pathogenicity and histopathology of fish (V. parahaemolyticus 1.2164) and human (V. parahaemolyticus 17) strains in a zebrafish (Danio rerio). We found that different infection routes resulted in different mortality in zebrafish. Moreover, death due to V. parahaemolyticus 1.2164 infection occurred quicker than that caused by V. parahaemolyticus 17 infection. Hematoxylin-eosin staining of liver, kidney and intestine sections showed histological lesions in all three organs after infection with either strain. V. parahaemolyticus 1.2164 caused more severe damage than V. parahaemolyticus 17. In particular, V. parahaemolyticus 1.2164 treatment induced more serious hydropic degeneration and venous sinus necrosis in the liver than V. parahaemolyticus 17 treatment. The expression levels of three proinflammatory cytokines, interleukin 1β (il1β), interferon phi 1 (ifnϕ1) and tumor necrosis factor α (tnfα), as determined by quantitative real-time PCR, were upregulated in all examined tissues of infected fish. Notably, the peak levels of tnfα were significantly higher than those of il1β and ifnϕ1, suggesting, together with pathological results, that tnfα and il1β play an important role in acute sepsis. High amounts of tnfα may be related to acute liver necrosis, while ifnϕ1 may respond to V. parahaemolyticus and play an antibacterial role for chronically infected adult zebrafish. Taken together, our results suggest that the zebrafish model of V. parahaemolyticus infection is useful for studying strain differences in V. parahaemolyticus pathogenesis. Copyright © 2015 Elsevier Ltd. All rights reserved.
Kamani, Joshua; Baneth, Gad; Gutiérrez, Ricardo; Nachum-Biala, Yaarit; Mumcuoglu, Kosta Y; Harrus, Shimon
Rodents are hosts of numerous pathogenic agents of public health importance globally. Their ability to harbor these pathogens without showing overt clinical signs of disease has epidemiologic consequences. In some rural settings in Nigeria, humans and rodents do not only share feeds and abode, but the latter may end up on the table of the former as a source of protein, thereby increasing the risks of disease transmission. Molecular assays were used to detect and characterize two agents of zoonotic importance, Coxiella burnetii and Rickettsia spp. in 194 peridomestic rodents captured in a peri-urban setting in Nigeria, and 32 pools of ectoparasites removed from them, to determine their possible role in the epidemiology of these diseases in this country. Targeting and characterizing the insertion sequence IS1111, C. burnetii DNA was detected in 4 out of 194 (2.1%) rodents comprising 3 out of 121 (2.5%) Rattus norvegicus and 1 out of 48 (2.1%) Rattus rattus screened in this study. Rickettsia spp. DNA was detected in two Rhipicephalus sanginueus sensu lato pools (i.e. RT1 and RT4) using the citrate synthase (gltA) gene and further characterized by amplification and sequence analysis of six genes to determine their identity. The RT1 sample consistently gave 98-100% identity to Rickettsia conorii str. Malish 7 for the various genes and loci studied. However, the identity of RT4 could not be definitively determined due to variable identities to different Rickettsia spp. according to the gene or loci under consideration. Further isolation study to determine if the RT4 characterized is a new variant or a mixture of sequences of different rickettsiae within the pool will be worthwhile. Copyright © 2017 Elsevier GmbH. All rights reserved.
Greig, Denise J.; Ip, Hon S.; Gulland, Frances M. D.; Miller, Woutrina A.; Conrad, Patricia A.; Field, Cara L.; Fleetwood, Michelle; Harvey, James T.; Jang, Spencer; Packham, Andrea; Wheeler, Elizabeth; Hall, Ailsa J.
The infection status of harbor seals Phoca vitulina in central California, USA, was evaluated through broad surveillance for pathogens in stranded and wild-caught animals from 2001 to 2008, with most samples collected in 2007 and 2008. Stranded animals from Mendocino County to San Luis Obispo County were sampled at a rehabilitation facility: The Marine Mammal Center (TMMC, n = 175); wild-caught animals were sampled at 2 locations: San Francisco Bay (SF, n = 78) and Tomales Bay (TB, n = 97), that differed in degree of urbanization. Low prevalences of Salmonella, Campylobacter, Giardia, and Cryptosporidium were detected in the feces of stranded and wild-caught seals. Clostridium perfringens and Escherichia coli were more prevalent in the feces of stranded (58% [78 out of 135] and 76% [102 out of 135]) than wild-caught (42% [45 out of 106] and 66% [68 out of 106]) seals, whereas Vibrio spp. were 16 times more likely to be cultured from the feces of seals from SF than TB or TMMC (p < 0.005). Brucella DNA was detected in 3.4% of dead stranded harbor seals (2 out of 58). Type A influenza was isolated from feces of 1 out of 96 wild-caught seals. Exposure to Toxoplasma gondii, Sarcocystis neurona, and type A influenza was only detected in the wild-caught harbor seals (post-weaning age classes), whereas antibody titers to Leptospira spp. were detected in stranded and wild-caught seals. No stranded (n = 109) or wild-caught (n = 217) harbor seals had antibodies to phocine distemper virus, although a single low titer to canine distemper virus was detected. These results highlight the role of harbor seals as sentinel species for zoonotic and terrestrial pathogens in the marine environment.
Chakma, S; Picard, J; Duffy, R; Constantinoiu, C; Gummow, B
In 1964, Brucella was isolated from rodents trapped in Wooroonooran National Park (WNP), in Northern Queensland, Australia. Genotyping of bacterial isolates in 2008 determined that they were a novel Brucella species. This study attempted to reisolate this species of Brucella from rodents living in the boundary area adjacent to WNP and to establish which endo- and ecto-parasites and bacterial agents were being carried by non-indigenous rodents at this interface. Seventy non-indigenous rodents were trapped [Mus musculus (52), Rattus rattus (17) and Rattus norvegicus (1)], euthanized and sampled on four properties adjacent to the WNP in July 2012. Organ pools were screened by culture for Salmonella, Leptospira and Brucella species, real-time PCR for Coxiella burnetii and conventional PCR for Leptospira. Collected ecto- and endo-parasites were identified using morphological criteria. The percentage of rodents carrying pathogens were Leptospira (40%), Salmonella choleraesuis ssp. arizonae (14.29%), ectoparasites (21.42%) and endoparasites (87%). Brucella and C. burnetii were not identified, and it was concluded that their prevalences were below 12%. Two rodent-specific helminthic species, namely Syphacia obvelata (2.86%) and Nippostrongylus brasiliensis (85.71%), were identified. The most prevalent ectoparasites belonged to Laelaps spp. (41.17%) followed by Polyplax spp. (23.53%), Hoplopleura spp. (17.65%), Ixodes holocyclus (17.64%) and Stephanocircus harrisoni (5.88%), respectively. These ectoparasites, except S. harrisoni, are known to transmit zoonotic pathogens such as Rickettsia spp. from rat to rat and could be transmitted to humans by other arthropods that bite humans. The high prevalence of pathogenic Leptospira species is of significant public health concern. This is the first known study of zoonotic agents carried by non-indigenous rodents living in the Australian wet-tropical forest interface. © 2015 Blackwell Verlag GmbH.
Holden, Matthew T. G.; Hauser, Heidi; Sanders, Mandy; Ngo, Thi Hoa; Cherevach, Inna; Cronin, Ann; Goodhead, Ian; Mungall, Karen; Quail, Michael A.; Price, Claire; Rabbinowitsch, Ester; Sharp, Sarah; Croucher, Nicholas J.; Chieu, Tran Bich; Thi Hoang Mai, Nguyen; Diep, To Song; Chinh, Nguyen Tran; Kehoe, Michael; Leigh, James A.; Ward, Philip N.; Dowson, Christopher G.; Whatmore, Adrian M.; Chanter, Neil; Iversen, Pernille; Gottschalk, Marcelo; Slater, Josh D.; Smith, Hilde E.; Spratt, Brian G.; Xu, Jianguo; Ye, Changyun; Bentley, Stephen; Barrell, Barclay G.; Schultsz, Constance; Maskell, Duncan J.; Parkhill, Julian
Background Streptococcus suis is a zoonotic pathogen that infects pigs and can occasionally cause serious infections in humans. S. suis infections occur sporadically in human Europe and North America, but a recent major outbreak has been described in China with high levels of mortality. The mechanisms of S. suis pathogenesis in humans and pigs are poorly understood. Methodology/Principal Findings The sequencing of whole genomes of S. suis isolates provides opportunities to investigate the genetic basis of infection. Here we describe whole genome sequences of three S. suis strains from the same lineage: one from European pigs, and two from human cases from China and Vietnam. Comparative genomic analysis was used to investigate the variability of these strains. S. suis is phylogenetically distinct from other Streptococcus species for which genome sequences are currently available. Accordingly, ∼40% of the ∼2 Mb genome is unique in comparison to other Streptococcus species. Finer genomic comparisons within the species showed a high level of sequence conservation; virtually all of the genome is common to the S. suis strains. The only exceptions are three ∼90 kb regions, present in the two isolates from humans, composed of integrative conjugative elements and transposons. Carried in these regions are coding sequences associated with drug resistance. In addition, small-scale sequence variation has generated pseudogenes in putative virulence and colonization factors. Conclusions/Significance The genomic inventories of genetically related S. suis strains, isolated from distinct hosts and diseases, exhibit high levels of conservation. However, the genomes provide evidence that horizontal gene transfer has contributed to the evolution of drug resistance. PMID:19603075
Nobori, Tatsuya; Velásquez, André C; Wu, Jingni; Kvitko, Brian H; Kremer, James M; Wang, Yiming; He, Sheng Yang; Tsuda, Kenichi
Plant pathogens can cause serious diseases that impact global agriculture. The plant innate immunity, when fully activated, can halt pathogen growth in plants. Despite extensive studies into the molecular and genetic bases of plant immunity against pathogens, the influence of plant immunity in global pathogen metabolism to restrict pathogen growth is poorly understood. Here, we developed RNA sequencing pipelines for analyzing bacterial transcriptomes in planta and determined high-resolution transcriptome patterns of the foliar bacterial pathogen Pseudomonas syringae in Arabidopsis thaliana with a total of 27 combinations of plant immunity mutants and bacterial strains. Bacterial transcriptomes were analyzed at 6 h post infection to capture early effects of plant immunity on bacterial processes and to avoid secondary effects caused by different bacterial population densities in planta We identified specific "immune-responsive" bacterial genes and processes, including those that are activated in susceptible plants and suppressed by plant immune activation. Expression patterns of immune-responsive bacterial genes at the early time point were tightly linked to later bacterial growth levels in different host genotypes. Moreover, we found that a bacterial iron acquisition pathway is commonly suppressed by multiple plant immune-signaling pathways. Overexpression of a P. syringae sigma factor gene involved in iron regulation and other processes partially countered bacterial growth restriction during the plant immune response triggered by AvrRpt2. Collectively, this study defines the effects of plant immunity on the transcriptome of a bacterial pathogen and sheds light on the enigmatic mechanisms of bacterial growth inhibition during the plant immune response.
Sritharan, T.; Palmer, A.; Sidhu, J. P. S.; Toze, S.
This study was aimed at evaluating the host specificity and host sensitivity of two bovine feces-associated bacterial (BacCow-UCD and cowM3) and one viral [bovine adenovirus (B-AVs)] microbial source tracking (MST) markers by screening 130 fecal and wastewater samples from 10 target and nontarget host groups in southeast Queensland, Australia. In addition, 36 water samples were collected from a reservoir and tested for the occurrence of all three bovine feces-associated markers along with fecal indicator bacteria (FIB), Campylobacter spp., Escherichia coli O157, and Salmonella spp. The overall host specificity values of the BacCow-UCD, cowM3, and B-AVs markers to differentiate between bovine and other nontarget host groups were 0.66, 0.88, and 1.00, respectively (maximum value of 1.00). The overall host sensitivity values of these markers, however, in composite bovine wastewater and individual bovine fecal DNA samples were 0.93, 0.90, and 0.60, respectively (maximum value of 1.00). Among the 36 water samples tested, 56%, 22%, and 6% samples were PCR positive for the BacCow-UCD, cowM3, and B-AVs markers, respectively. Among the 36 samples tested, 50% and 14% samples were PCR positive for the Campylobacter 16S rRNA and E. coli O157 rfbE genes, respectively. Based on the results, we recommend that multiple bovine feces-associated markers be used if possible for bovine fecal pollution tracking. Nonetheless, the presence of the multiple bovine feces-associated markers along with the presence of potential zoonotic pathogens indicates bovine fecal pollution in the reservoir water samples. Further research is required to understand the decay rates of these markers in relation to FIB and zoonotic pathogens. PMID:23417003
Wood, James L. N.; Leach, Melissa; Waldman, Linda; MacGregor, Hayley; Fooks, Anthony R.; Jones, Kate E.; Restif, Olivier; Dechmann, Dina; Hayman, David T. S.; Baker, Kate S.; Peel, Alison J.; Kamins, Alexandra O.; Fahr, Jakob; Ntiamoa-Baidu, Yaa; Suu-Ire, Richard; Breiman, Robert F.; Epstein, Jonathan H.; Field, Hume E.; Cunningham, Andrew A.
Many serious emerging zoonotic infections have recently arisen from bats, including Ebola, Marburg, SARS-coronavirus, Hendra, Nipah, and a number of rabies and rabies-related viruses, consistent with the overall observation that wildlife are an important source of emerging zoonoses for the human population. Mechanisms underlying the recognized association between ecosystem health and human health remain poorly understood and responding appropriately to the ecological, social and economic conditions that facilitate disease emergence and transmission represents a substantial societal challenge. In the context of disease emergence from wildlife, wildlife and habitat should be conserved, which in turn will preserve vital ecosystem structure and function, which has broader implications for human wellbeing and environmental sustainability, while simultaneously minimizing the spillover of pathogens from wild animals into human beings. In this review, we propose a novel framework for the holistic and interdisciplinary investigation of zoonotic disease emergence and its drivers, using the spillover of bat pathogens as a case study. This study has been developed to gain a detailed interdisciplinary understanding, and it combines cutting-edge perspectives from both natural and social sciences, linked to policy impacts on public health, land use and conservation. PMID:22966143
Tran Van Nhieu, Guy; Arbibe, Laurence
During the course of infection, pathogens often induce changes in gene expression in host cells and these changes can be long lasting and global or transient and of limited amplitude. Defining how, when, and why bacterial pathogens reprogram host cells represents an exciting challenge that opens up the opportunity to grasp the essence of pathogenesis and its molecular details.
Cano-Terriza, David; Guerra, Rafael; Lecollinet, Sylvie; Cerdà-Cuéllar, Marta; Cabezón, Oscar; Almería, Sonia; García-Bocanegra, Ignacio
A cross-sectional study was carried out to determine the prevalence of pathogenic zoonotic agents (flaviviruses, avian influenza viruses (AIVs), Salmonella spp. and Toxoplasma gondii) in feral pigeons and sympatric zoo animals from Córdoba (Southern Spain) between 2013 and 2014. Antibodies against flaviviruses were detected in 7.8% out of 142 (CI95%: 3.7-11.8) pigeons, and 8.2% of 49 (CI95%: 0.9-15.4) of zoo animals tested. Antibodies with specificity against West Nile virus (WNV) and Usutu virus (USUV) were confirmed both in pigeons and in zoo birds. Even though seropositivity to AIVs was not detected in any of the analyzed pigeons, 17.9% of 28 (CI95%: 3.7-32.0) zoo birds tested showed positive results. Salmonella spp. was not isolated in any of 152 fecal samples collected from pigeons, while 6.8% of 44 zoo animals were positive. Antibodies against T. gondii were found in 9.2% of 142 (CI95%: 4.8-13.6) feral pigeons and 26.9% of 108 (CI95%: 19.6-34.1) zoo animals. This is the first study on flaviviruses and T. gondii in feral pigeons and captive zoo species in Spain. Antibodies against WNV and USUV detected in non-migratory pigeons and captive zoo animals indicate local circulation of these emerging pathogens in the study area. T. gondii was widespread in species analyzed. This finding could be of importance for Public Health and Conservation of endangered species present in zoo parks. Pigeons and zoo animals may be included as sentinel species for monitoring zoonotic pathogens in urban areas. Copyright © 2015 Elsevier Ltd. All rights reserved.
Kimmey, Jacqueline M.; Stallings, Christina L.
Research in recent years has focused significantly on the role of selective macroautophagy in targeting intracellular pathogens for lysosomal degradation, a process termed xenophagy. In this review we evaluate the proposed roles for xenophagy in controlling bacterial infection, highlighting the concept that successful pathogens have evolved ways to subvert or exploit this defense, minimizing the actual effectiveness of xenophagy in innate immunity. Instead, studies in animal models have revealed that autophagy-associated proteins often function outside of xenophagy to influence bacterial pathogenesis. In light of current efforts to manipulate autophagy and the development of host-directed therapies to fight bacterial infections, we also discuss the implications stemming from the complicated relationship that exists between autophagy and bacterial pathogens. PMID:27866924
Many wild swine populations in different parts of the World have experienced an unprecedented demographic explosion that may result in increased exposure of humans to wild swine zoonotic pathogens. Interactions between humans and wild swine leading to pathogen transmission could come from different ways, being hunters and game professionals the most exposed to acquiring infections from wild swine. However, increasing human settlements in semi-natural areas, outdoor activities, socio-economic changes and food habits may increase the rate of exposure to wild swine zoonotic pathogens and to potentially emerging pathogens from wild swine. Frequent and increasing contact rate between humans and wild swine points to an increasing chance of zoonotic pathogens arising from wild swine to be transmitted to humans. Whether this frequent contact could lead to new zoonotic pathogens emerging from wild swine to cause human epidemics or emerging disease outbreaks is difficult to predict, and assessment should be based on thorough epidemiologic surveillance. Additionally, several gaps in knowledge on wild swine global population dynamics trends and wild swine-zoonotic pathogen interactions should be addressed to correctly assess the potential role of wild swine in the emergence of diseases in humans. In this work, viruses such as hepatitis E virus, Japanese encephalitis virus, Influenza virus and Nipah virus, and bacteria such as Salmonella spp., Shiga toxin-producing Escherichia coli, Campylobacter spp. and Leptospira spp. have been identified as the most prone to be transmitted from wild swine to humans on the basis of geographic spread in wild swine populations worldwide, pathogen circulation rates in wild swine populations, wild swine population trends in endemic areas, susceptibility of humans to infection, transmissibility from wild swine to humans and existing evidence of wild swine-human transmission events. © 2015 Blackwell Verlag GmbH.
Orji, Frank Anayo; Ugbogu, Ositadinma Chinyere; Ugbogu, Eziuche Amadike; Barbabosa-Pliego, Alberto; Monroy, Jose Cedillo; Elghandour, Mona M M Y; Salem, Abdelfattah Z M
Over 250 species of resident flora in the class of bacteria are known to be associated with humans. These conventional flora compositions is often determined by factors which may not be limited to genetics, age, sex, stress and nutrition of humans. Man is constantly in contact with bacteria through media such as air, water, soil and food. This paper reviews the concept of bacterial pathogenesis from the sequential point of colonization to tissue injury. The paper in addition to examination of the factors which enhance virulence in bacterial pathogens also x-rayed the concept of pathogenicity islands and the next generation approaches or rather current trends/methods used in the bacterial pathogenicity investigations. In terms of pathogenicity which of course is the capacity to cause disease in animals, requires that the attacking bacterial strain is virulent, and has ability to bypass the host immune defensive mechanisms. In order to achieve or exhibit pathogenicity, the virulence factors required by microorganisms include capsule, pigments, enzymes, iron acquisition through siderophores. Bacterial Pathogenicity Islands as a distinct concept in bacterial pathogenesis are just loci on the chromosome or extra chromosomal units which are acquired by horizontal gene transfer within pathogens in a microbial community or biofilm. In the area of laboratory investigations, bacterial pathogenesis was initially carried out using culture dependent approaches, which can only detect about 1% of human and veterinary-important pathogens. However, in the recent paradigms shift, the use of proteomics, metagenomics, phylogenetic tree analyses, spooligotyping, and finger printing etc. have made it possible that 100% of the bacterial pathogens in nature can be extensively studied. Copyright © 2018 Elsevier Ltd. All rights reserved.
Joseph, Sandeep J; Marti, Hanna; Didelot, Xavier; Read, Timothy D; Dean, Deborah
Species closely related to the human pathogen Chlamydia trachomatis (Ct) have recently been found to cause zoonotic infections, posing a public health threat especially in the case of tetracycline resistant Chlamydia suis (Cs) strains. These strains acquired a tet(C)-containing cassette via horizontal gene transfer (HGT). Genomes of 11 Cs strains from various tissues were sequenced to reconstruct evolutionary pathway(s) for tet(C) HGT. Cs had the highest recombination rate of Chlamydia species studied to date. Admixture occurred among Cs strains and with Chlamydia muridarum but not with Ct Although in vitro tet(C) cassette exchange with Ct has been documented, in vivo evidence may require examining human samples from Ct and Cs co-infected sites. Molecular-clock dating indicated that ancestral clades of resistant Cs strains predated the 1947 discovery of tetracycline, which was subsequently used in animal feed. The cassette likely spread throughout Cs strains by homologous recombination after acquisition from an external source, and our analysis suggests Betaproteobacteria as the origin. Selective pressure from tetracycline may be responsible for recent bottlenecks in Cs populations. Since tetracycline is an important antibiotic for treating Ct, zoonotic infections at mutual sites of infection indicate the possibility for cassette transfer and major public health repercussions. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
Barnes, Ian; Thomas, Mark G
Reports of bacterial pathogen DNA sequences obtained from archaeological bone specimens raise the possibility of greatly improving our understanding of the history of infectious diseases. However, the survival of pathogen DNA over long time periods is poorly characterized, and scepticism remains about the reliability of these data. In order to explore the survival of bacterial pathogen DNA in bone specimens, we analysed samples from 59 eighteenth and twentieth century individuals known to have been infected with either Mycobacterium tuberculosis or Treponema pallidum. No reproducible evidence of surviving pathogen DNA was obtained, despite the use of extraction and PCR-amplification methods determined to be highly sensitive. These data suggest that previous studies need to be interpreted with caution, and we propose that a much greater emphasis is placed on understanding how pathogen DNA survives in archaeological material, and how its presence can be properly verified and used. PMID:16608682
Ionita, Mariana; Mitrea, Ioan Liviu; Pfister, Kurt; Hamel, Dietmar; Silaghi, Cornelia
The aim of the present study was to provide a preliminary insight into the diversity of tick-borne pathogens circulating at the domestic host-tick interface in Romania. For this, feeding and questing ticks were analyzed by real-time polymerase chain reaction (PCR) for the presence of Anaplasma phagocytophilum, Anaplasma platys, Ehrlichia canis, Borrelia burgdorferi sensu latu, and by PCR and subsequent sequencing for Rickettsia spp., Babesia spp. and Theileria spp. A total of 382 ticks, encompassing 5 species from 4 genera, were collected in April-July 2010 from different areas of Romania; of them, 40 were questing ticks and the remainder was collected from naturally infested cattle, sheep, goats, horses or dogs. Tick species analyzed included Ixodes ricinus, Dermacentor marginatus, Hyalomma marginatum, Rhipicephalus bursa, and Rhipicephalus sanguineus. Four rickettsiae of the spotted fever group of zoonotic concern were identified for the first time in Romania: Rickettsia monacensis and Rickettsia helvetica in I. ricinus, and Rickettsia slovaca and Rickettsia raoultii in D. marginatus. Other zoonotic pathogens such as A. phagocytophilum, Borrelia afzelii, and Babesia microti were found in I. ricinus. Pathogens of veterinary importance were also identified, including Theileria equi in H. marginatum, Babesia occultans in D. marginatus and H. marginatum, Theileria orientalis/sergenti/buffeli-group in I. ricinus and in H. marginatum and E. canis in R. sanguineus. These findings show a wide distribution of very diverse bacterial and protozoan pathogens at the domestic host-tick interface in Romania, with the potential of causing both animal and human diseases. Copyright © 2013 Elsevier B.V. All rights reserved.
The key first step in evaluating pathogen levels in suspected contaminated water is concentration. Concentration methods tend to be specific for a particular pathogen group or genus, for example viruses or Cryptosporidium, requiring multiple methods if the sampling program is targeting more than on...
Salkeld, Daniel J; Padgett, Kerry A; Jones, James Holland
Zoonotic pathogens are significant burdens on global public health. Because they are transmitted to humans from non-human animals, the transmission dynamics of zoonoses are necessarily influenced by the ecology of their animal hosts and vectors. The 'dilution effect' proposes that increased species diversity reduces disease risk, suggesting that conservation and public health initiatives can work synergistically to improve human health and wildlife biodiversity. However, the meta-analysis that we present here indicates a weak and highly heterogeneous relationship between host biodiversity and disease. Our results suggest that disease risk is more likely a local phenomenon that relies on the specific composition of reservoir hosts and vectors, and their ecology, rather than patterns of species biodiversity. © 2013 Blackwell Publishing Ltd/CNRS.
Sahin, Orhan; Fitzgerald, Collette; Stroika, Steven; Zhao, Shaohua; Sippy, Rachel J; Kwan, Patrick; Plummer, Paul J; Han, Jing; Yaeger, Michael J; Zhang, Qijing
Campylobacter jejuni is a major zoonotic pathogen. A highly virulent, tetracycline-resistant C. jejuni clone (clone SA) has recently emerged in ruminant reservoirs and has become the predominant cause of sheep abortion in the United States. To determine whether clone SA is associated with human disease, we compared the clinical isolates of clone SA from sheep abortions with the human isolates of the PulseNet National Campylobacter databases at the CDC and the FDA using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and serotyping. The combined SmaI and KpnI PFGE pattern designations of clone SA from sheep were indistinguishable from those of 123 (9.03%) human C. jejuni isolates (total, 1,361) in the CDC database, among which 56 were associated with sporadic infections and 67 were associated with outbreaks that occurred in multiple states from 2003 to 2010. Most of the outbreaks were attributed to raw milk, while the sources for most of the sporadic cases were unknown. All clone SA isolates examined, including PFGE-matched human isolates, belong to sequence type 8 (ST-8) by MLST and serotype HS:1,8, further indicating the clonality of the related isolates from different host species. Additionally, C. jejuni clone SA was identified in raw milk, cattle feces, the feces and bile of healthy sheep, and abortion cases of cattle and goats, indicating the broad distribution of this pathogenic clone in ruminants. These results provide strong molecular and epidemiological evidence for zoonotic transmission of this emergent clone from ruminants to humans and indicate that C. jejuni clone SA is an important threat to public health.
Hodgers, L.; Sidhu, J. P. S.; Toze, S.
In this study, the microbiological quality of household tap water samples fed from rainwater tanks was assessed by monitoring the numbers of Escherichia coli bacteria and enterococci from 24 households in Southeast Queensland (SEQ), Australia. Quantitative PCR (qPCR) was also used for the quantitative detection of zoonotic pathogens in water samples from rainwater tanks and connected household taps. The numbers of zoonotic pathogens were also estimated in fecal samples from possums and various species of birds by using qPCR, as possums and birds are considered to be the potential sources of fecal contamination in roof-harvested rainwater (RHRW). Among the 24 households, 63% of rainwater tank and 58% of connected household tap water (CHTW) samples contained E. coli and exceeded Australian drinking water guidelines of <1 CFU E. coli per 100 ml water. Similarly, 92% of rainwater tanks and 83% of CHTW samples also contained enterococci. In all, 21%, 4%, and 13% of rainwater tank samples contained Campylobacter spp., Salmonella spp., and Giardia lamblia, respectively. Similarly, 21% of rainwater tank and 13% of CHTW samples contained Campylobacter spp. and G. lamblia, respectively. The number of E. coli (P = 0.78), Enterococcus (P = 0.64), Campylobacter (P = 0.44), and G. lamblia (P = 0.50) cells in rainwater tanks did not differ significantly from the numbers observed in the CHTW samples. Among the 40 possum fecal samples tested, Campylobacter spp., Cryptosporidium parvum, and G. lamblia were detected in 60%, 13%, and 30% of samples, respectively. Among the 38 bird fecal samples tested, Campylobacter spp., Salmonella spp., C. parvum, and G. lamblia were detected in 24%, 11%, 5%, and 13% of the samples, respectively. Household tap water samples fed from rainwater tanks tested in the study appeared to be highly variable. Regular cleaning of roofs and gutters, along with pruning of overhanging tree branches, might also prove effective in reducing animal fecal
Ahmed, W; Hodgers, L; Sidhu, J P S; Toze, S
In this study, the microbiological quality of household tap water samples fed from rainwater tanks was assessed by monitoring the numbers of Escherichia coli bacteria and enterococci from 24 households in Southeast Queensland (SEQ), Australia. Quantitative PCR (qPCR) was also used for the quantitative detection of zoonotic pathogens in water samples from rainwater tanks and connected household taps. The numbers of zoonotic pathogens were also estimated in fecal samples from possums and various species of birds by using qPCR, as possums and birds are considered to be the potential sources of fecal contamination in roof-harvested rainwater (RHRW). Among the 24 households, 63% of rainwater tank and 58% of connected household tap water (CHTW) samples contained E. coli and exceeded Australian drinking water guidelines of <1 CFU E. coli per 100 ml water. Similarly, 92% of rainwater tanks and 83% of CHTW samples also contained enterococci. In all, 21%, 4%, and 13% of rainwater tank samples contained Campylobacter spp., Salmonella spp., and Giardia lamblia, respectively. Similarly, 21% of rainwater tank and 13% of CHTW samples contained Campylobacter spp. and G. lamblia, respectively. The number of E. coli (P = 0.78), Enterococcus (P = 0.64), Campylobacter (P = 0.44), and G. lamblia (P = 0.50) cells in rainwater tanks did not differ significantly from the numbers observed in the CHTW samples. Among the 40 possum fecal samples tested, Campylobacter spp., Cryptosporidium parvum, and G. lamblia were detected in 60%, 13%, and 30% of samples, respectively. Among the 38 bird fecal samples tested, Campylobacter spp., Salmonella spp., C. parvum, and G. lamblia were detected in 24%, 11%, 5%, and 13% of the samples, respectively. Household tap water samples fed from rainwater tanks tested in the study appeared to be highly variable. Regular cleaning of roofs and gutters, along with pruning of overhanging tree branches, might also prove effective in reducing animal fecal
Sahin, Orhan; Fitzgerald, Collette; Stroika, Steven; Zhao, Shaohua; Sippy, Rachel J.; Kwan, Patrick; Plummer, Paul J.; Han, Jing; Yaeger, Michael J.
Campylobacter jejuni is a major zoonotic pathogen. A highly virulent, tetracycline-resistant C. jejuni clone (clone SA) has recently emerged in ruminant reservoirs and has become the predominant cause of sheep abortion in the United States. To determine whether clone SA is associated with human disease, we compared the clinical isolates of clone SA from sheep abortions with the human isolates of the PulseNet National Campylobacter databases at the CDC and the FDA using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and serotyping. The combined SmaI and KpnI PFGE pattern designations of clone SA from sheep were indistinguishable from those of 123 (9.03%) human C. jejuni isolates (total, 1,361) in the CDC database, among which 56 were associated with sporadic infections and 67 were associated with outbreaks that occurred in multiple states from 2003 to 2010. Most of the outbreaks were attributed to raw milk, while the sources for most of the sporadic cases were unknown. All clone SA isolates examined, including PFGE-matched human isolates, belong to sequence type 8 (ST-8) by MLST and serotype HS:1,8, further indicating the clonality of the related isolates from different host species. Additionally, C. jejuni clone SA was identified in raw milk, cattle feces, the feces and bile of healthy sheep, and abortion cases of cattle and goats, indicating the broad distribution of this pathogenic clone in ruminants. These results provide strong molecular and epidemiological evidence for zoonotic transmission of this emergent clone from ruminants to humans and indicate that C. jejuni clone SA is an important threat to public health. PMID:22189122
Baroudi, Djamel; Khelef, Djamel; Goucem, Rachid; Adjou, Karim T; Adamu, Haileeyesus; Zhang, Hongwei; Xiao, Lihua
Only a small number of birds have been identified by molecular techniques as having Cryptosporidium meleagridis, the third most important species for human cryptosporidiosis. In this study, using PCR-RFLP analysis of the small subunit (SSU) rRNA gene, we examined the ileum of 90 dead chickens from 23 farms and 57 dead turkeys from 16 farms in Algeria for Cryptosporidium spp. C. meleagridis-positive specimens were subtyped by sequence analysis of the 60 kDa glycoprotein gene. Cryptosporidium infection rates were 34% and 44% in chickens and turkeys, respectively, with all positive turkeys (25) and most positive chickens (26/31) having C. meleagridis. All C. meleagridis specimens belonged to a new subtype family. The frequent occurrence of C. meleagridis in chickens and turkeys illustrates the potential for zoonotic transmission of cryptosporidiosis in Algeria. Published by Elsevier B.V.
Mellouk, Nora; Enninga, Jost
Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it. PMID:27092296
Mellouk, Nora; Enninga, Jost
Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it.
Arenas, Nelson E; Abril, Diego A; Valencia, Paola; Khandige, Surabhi; Soto, Carlos Yesid; Moreno-Melo, Vilma
Hazardous practices regarding antibiotics misuse, unsanitary milking procedures, and the commercial sales of raw milk and unpasteurized dairy products are currently being practiced by livestock farmers in the Sumapaz region (Colombia). The purpose of this study was to screen for food-borne and zoonotic pathogens associated with local livestock practices. We evaluated 1098 cows from 46 livestock farms in the Sumapaz region that were selected by random. Of the total population of cattle, 962 animals (88%) were tested for bovine TB using a caudal-fold tuberculin test and 546 (50%) for brucellosis by a competitive ELISA. In the population tested, 23 cows were positive for Brucella sp. representing a 4.2% seroprevalence and no cases of bovine tuberculosis were found. In addition, food-borne contamination with Escherichia coli and Staphylococcus aureus was assessed together with antibiotic susceptibility for ten different antibiotics in milk samples from 16 livestock farms. We found that 12 of the farms (75%) were contaminated with these food-borne pathogens. Noteworthy, all of the isolated pathogenic strains were resistant to multiple antibiotics, primarily to oxytetracycline and erythromycin. Our findings suggest that livestock products could be a source of exposure to Brucella and multidrug-resistant E. coli and S. aureus strains as a result of unhygienic livestock practices in the Sumapaz region. Training in good farming practices is the key to improving safety in food production.
Murphy, Colleen P.; Reid-Smith, Richard J.; Boerlin, Patrick; Weese, J. Scott; Prescott, John F.; Janecko, Nicol; Hassard, Lori; McEwen, Scott A.
Hospital-based infection control in veterinary medicine is emerging and the role of the environment in hospital-acquired infections (HAI) in veterinary hospitals is largely unknown. This study was initiated to determine the recovery of Escherichia coli and selected veterinary and zoonotic pathogens from the environments of 101 community veterinary hospitals. The proportion of hospitals with positive environmental swabs were: E. coli — 92%, Clostridium difficile — 58%, methicillin-resistant Staphylococcus aureus (MRSA) — 9%, CMY-2 producing E. coli — 9%, methicillin-resistant Staphylococcus pseudintermedius — 7%, and Salmonella — 2%. Vancomycin-resistant Enterococcus spp., canine parvovirus, and feline calicivirus were not isolated. Prevalence of antimicrobial resistance in E. coli isolates was low. Important potential veterinary and human pathogens were recovered including Canadian epidemic strains MRSA-2 and MRSA-5, and C. difficile ribotype 027. There is an environmental reservoir of pathogens in veterinary hospitals; therefore, additional studies are required to characterize risk factors associated with HAI in companion animals, including the role of the environment. PMID:21119862
Murphy, Colleen P; Reid-Smith, Richard J; Boerlin, Patrick; Weese, J Scott; Prescott, John F; Janecko, Nicol; Hassard, Lori; McEwen, Scott A
Hospital-based infection control in veterinary medicine is emerging and the role of the environment in hospital-acquired infections (HAI) in veterinary hospitals is largely unknown. This study was initiated to determine the recovery of Escherichia coli and selected veterinary and zoonotic pathogens from the environments of 101 community veterinary hospitals. The proportion of hospitals with positive environmental swabs were: E. coli--92%, Clostridium difficile--58%, methicillin-resistant Staphylococcus aureus (MRSA)--9%, CMY-2 producing E. coli--9%, methicillin-resistant Staphylococcus pseudintermedius--7%, and Salmonella--2%. Vancomycin-resistant Enterococcus spp., canine parvovirus, and feline calicivirus were not isolated. Prevalence of antimicrobial resistance in E. coli isolates was low. Important potential veterinary and human pathogens were recovered including Canadian epidemic strains MRSA-2 and MRSA-5, and C. difficile ribotype 027. There is an environmental reservoir of pathogens in veterinary hospitals; therefore, additional studies are required to characterize risk factors associated with HAI in companion animals, including the role of the environment.
Henry, Elizabeth; Yadeta, Koste A; Coaker, Gitta
Bacterial pathogens can cause multiple plant diseases and plants rely on their innate immune system to recognize and actively respond to these microbes. The plant innate immune system comprises extracellular pattern recognition receptors that recognize conserved microbial patterns and intracellular nucleotide binding leucine-rich repeat (NLR) proteins that recognize specific bacterial effectors delivered into host cells. Plants lack the adaptive immune branch present in animals, but still afford flexibility to pathogen attack through systemic and transgenerational resistance. Here, we focus on current research in plant immune responses against bacterial pathogens. Recent studies shed light onto the activation and inactivation of pattern recognition receptors and systemic acquired resistance. New research has also uncovered additional layers of complexity surrounding NLR immune receptor activation, cooperation and sub-cellular localizations. Taken together, these recent advances bring us closer to understanding the web of molecular interactions responsible for coordinating defense responses and ultimately resistance. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.
Feng, Feng; Zhou, Jian-Min
Effectors secreted by the bacterial type III system play a central role in the interaction between Gram-negative bacterial pathogens and their host plants. Recent advances in the effector studies have helped cementing several key concepts concerning bacterial pathogenesis, plant immunity, and plant-pathogen co-evolution. Type III effectors use a variety of biochemical mechanisms to target specific host proteins or DNA for pathogenesis. The identifications of their host targets led to the identification of novel components of plant innate immune system. Key modules of plant immune signaling pathways such as immune receptor complexes and MAPK cascades have emerged as a major battle ground for host-pathogen adaptation. These modules are attacked by multiple type III effectors, and some components of these modules have evolved to actively sense the effectors and trigger immunity. Copyright © 2012 Elsevier Ltd. All rights reserved.
Pareja, Maria Eugenia Mansilla; Colombo, Maria I
Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will describe the means used by diverse bacterial pathogens to survive intracellularly and how they are recognized by the autophagic molecular machinery, as well as the mechanisms used to avoid autophagic clearance.
Wallace, N; Zani, A; Abrams, E; Sun, Y
Bacterial enteric pathogens are responsible for a tremendous amount of foodborne illnesses every year through the consumption of contaminated food products. During their transit from contaminated food sources to the host gastrointestinal tract, these pathogens are exposed and must adapt to fluctuating oxygen levels to successfully colonize the host and cause diseases. However, the majority of enteric infection research has been conducted under aerobic conditions. To raise awareness of the importance in understanding the impact of oxygen, or lack of oxygen, on enteric pathogenesis, we describe in this review the metabolic and physiological responses of nine bacterial enteric pathogens exposed to environments with different oxygen levels. We further discuss the effects of oxygen levels on virulence regulation to establish potential connections between metabolic adaptations and bacterial pathogenesis. While not providing an exhaustive list of all bacterial pathogens, we highlight key differences and similarities among nine facultative anaerobic and microaerobic pathogens in this review to argue for a more in-depth understanding of the diverse impact oxygen levels have on enteric pathogenesis. Copyright © 2016 Elsevier Inc. All rights reserved.
Eisenreich, Wolfgang; Heesemann, Jürgen; Rudel, Thomas; Goebel, Werner
The interaction of bacterial pathogens with mammalian hosts leads to a variety of physiological responses of the interacting partners aimed at an adaptation to the new situation. These responses include multiple metabolic changes in the affected host cells which are most obvious when the pathogen replicates within host cells as in case of intracellular bacterial pathogens. While the pathogen tries to deprive nutrients from the host cell, the host cell in return takes various metabolic countermeasures against the nutrient theft. During this conflicting interaction, the pathogen triggers metabolic host cell responses by means of common cell envelope components and specific virulence-associated factors. These host reactions generally promote replication of the pathogen. There is growing evidence that pathogen-specific factors may interfere in different ways with the complex regulatory network that controls the carbon and nitrogen metabolism of mammalian cells. The host cell defense answers include general metabolic reactions, like the generation of oxygen- and/or nitrogen-reactive species, and more specific measures aimed to prevent access to essential nutrients for the respective pathogen. Accurate results on metabolic host cell responses are often hampered by the use of cancer cell lines that already exhibit various de-regulated reactions in the primary carbon metabolism. Hence, there is an urgent need for cellular models that more closely reflect the in vivo infection conditions. The exact knowledge of the metabolic host cell responses may provide new interesting concepts for antibacterial therapies. PMID:23847769
Millen, Hana T.; Gonnering, Jordan C.; Berg, Ryan K.; Spencer, Susan K.; Jokela, William E.; Pearce, John M.; Borchardt, Jackson S.; Borchardt, Mark A.
The key first step in evaluating pathogen levels in suspected contaminated water is concentration. Concentration methods tend to be specific for a particular pathogen group, for example US Environmental Protection Agency Method 1623 for Giardia and Cryptosporidium1, which means multiple methods are required if the sampling program is targeting more than one pathogen group. Another drawback of current methods is the equipment can be complicated and expensive, for example the VIRADEL method with the 1MDS cartridge filter for concentrating viruses2. In this article we describe how to construct glass wool filters for concentrating waterborne pathogens. After filter elution, the concentrate is amenable to a second concentration step, such as centrifugation, followed by pathogen detection and enumeration by cultural or molecular methods. The filters have several advantages. Construction is easy and the filters can be built to any size for meeting specific sampling requirements. The filter parts are inexpensive, making it possible to collect a large number of samples without severely impacting a project budget. Large sample volumes (100s to 1,000s L) can be concentrated depending on the rate of clogging from sample turbidity. The filters are highly portable and with minimal equipment, such as a pump and flow meter, they can be implemented in the field for sampling finished drinking water, surface water, groundwater, and agricultural runoff. Lastly, glass wool filtration is effective for concentrating a variety of pathogen types so only one method is necessary. Here we report on filter effectiveness in concentrating waterborne human enterovirus, Salmonella enterica, Cryptosporidium parvum, and avian influenza virus. PMID:22415031
Millen, Hana T.; Gonnering, Jordan C.; Berg, Ryan K.; Spencer, Susan K.; Jokela, William E.; Pearce, John M.; Borchardt, Jackson S.; Borchardt, Mark A.
The key first step in evaluating pathogen levels in suspected contaminated water is concentration. Concentration methods tend to be specific for a particular pathogen group, for example US Environmental Protection Agency Method 1623 for Giardia and Cryptosporidium1, which means multiple methods are required if the sampling program is targeting more than one pathogen group. Another drawback of current methods is the equipment can be complicated and expensive, for example the VIRADEL method with the 1MDS cartridge filter for concentrating viruses2. In this article we describe how to construct glass wool filters for concentrating waterborne pathogens. After filter elution, the concentrate is amenable to a second concentration step, such as centrifugation, followed by pathogen detection and enumeration by cultural or molecular methods. The filters have several advantages. Construction is easy and the filters can be built to any size for meeting specific sampling requirements. The filter parts are inexpensive, making it possible to collect a large number of samples without severely impacting a project budget. Large sample volumes (100s to 1,000s L) can be concentrated depending on the rate of clogging from sample turbidity. The filters are highly portable and with minimal equipment, such as a pump and flow meter, they can be implemented in the field for sampling finished drinking water, surface water, groundwater, and agricultural runoff. Lastly, glass wool filtration is effective for concentrating a variety of pathogen types so only one method is necessary. Here we report on filter effectiveness in concentrating waterborne human enterovirus, Salmonella enterica, Cryptosporidium parvum, and avian influenza virus.
Da Rold, Graziana; Ravagnan, Silvia; Soppelsa, Fabio; Porcellato, Elena; Soppelsa, Mauro; Obber, Federica; Citterio, Carlo Vittorio; Carlin, Sara; Danesi, Patrizia; Montarsi, Fabrizio; Capelli, Gioia
Northeastern Italy is a hotspot for several tick-borne pathogens, transmitted to animals and humans mainly by Ixodes ricinus. Here we compare the results of molecular monitoring of ticks and zoonotic TBPs over a six-year period, with the monitoring of red foxes (Vulpes vulpes) in an endemic area. In the period 2011-2016, 2,578 ticks were collected in 38 sites of 20 municipalities of Belluno Province. Individual adults (264), pooled larvae (n = 330) and nymphs (n = 1984) were screened for tick-borne encephalitis virus, Borrelia burgdorferi (s.l.), Rickettsia spp., Babesia spp., Anaplasma phagocytophilum and "Candidatus Neoehrlichia mikurensis" by specific SYBR green real-time PCR assays and sequencing. The spleens of 97 foxes, culled in the period 2015-2017 during sport hunting or population control programs, were also screened. Overall, nine different pathogens were found in I. ricinus nymph and adult ticks: Rickettsia helvetica (3.69%); R. monacensis (0.49%); four species of the B. burgdorferi (s.l.) complex [B. afzelii (1.51%); B. burgdorferi (s.s.) (1.25%); B. garinii (0.18%); and B. valaisiana (0.18%)]; A. phagocytophilum (3.29%); "Candidatus N. mikurensis" (1.73%); and Babesia venatorum (0.04%). Larvae were collected and screened in the first year only and two pools (0.6%) were positive for R. helvetica. Tick-borne encephalitis virus was not found in ticks although human cases do occur in the area. The rate of infection in ticks varied widely according to tick developmental stage, site and year of collection. As expected, adults were the most infected, with 27.6% harboring at least one pathogen compared to 7.3% of nymphs. Pathogens with a minimum infection rate above 1% were recorded every year. None of the pathogens found in ticks were detectable in the foxes, 52 (54%) of which were instead positive for Babesia cf. microti (also referred to as Babesia microti-like, "Theileria annae", "Babesia annae" and "Babesia vulpes"). The results show that foxes
Arenas, Yaxal; Mandel, Arkady; Lilge, Lothar
Fast detection of bacterial concentrations is important for the food industry and for healthcare. Early detection of infections and appropriate treatment is essential since, the delay of treatments for bacterial infections tends to be associated with higher mortality rates. In the food industry and in healthcare, standard procedures require the count of colony-forming units in order to quantify bacterial concentrations, however, this method is time consuming and reports require three days to be completed. An alternative is metabolic-colorimetric assays which provide time efficient in vitro bacterial concentrations. A colorimetric assay based on Resazurin was developed as a time kinetic assay (KRA) suitable for bacterial concentration measurements. An optimization was performed by finding excitation and emission wavelengths for fluorescent acquisition. A comparison of two non-related bacteria, foodborne pathogens Escherichia coli and Listeria monocytogenes, was performed in 96 well plates. A metabolic and clonogenic dependence was established for fluorescent kinetic signals.
Staley, Zachery R; Senkbeil, Jacob K; Rohr, Jason R; Harwood, Valerie J
Agrochemicals, fecal indicator bacteria (FIB), and pathogens frequently contaminate water simultaneously. No significant direct effects of fertilizer, atrazine, malathion, and chlorothalonil on the survival of Escherichia coli, Enterococcus faecalis, Salmonella enterica, human polyomaviruses, and adenovirus were detected, supporting the assertion that previously observed effects of agrochemicals on FIB were indirect.
Staley, Zachery R.; Senkbeil, Jacob K.; Rohr, Jason R.
Agrochemicals, fecal indicator bacteria (FIB), and pathogens frequently contaminate water simultaneously. No significant direct effects of fertilizer, atrazine, malathion, and chlorothalonil on the survival of Escherichia coli, Enterococcus faecalis, Salmonella enterica, human polyomaviruses, and adenovirus were detected, supporting the assertion that previously observed effects of agrochemicals on FIB were indirect. PMID:22961900
Hettinga, K A; van Valenberg, H J F; Lam, T J G M; van Hooijdonk, A C M
The ability to detect mastitis pathogens based on their volatile metabolites was studied. Milk samples from cows with clinical mastitis, caused by Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus uberis, Streptococcus dysgalactiae, and Escherichia coli were collected. In addition, samples from cows without clinical mastitis and with low somatic cell count (SCC) were collected for comparison. All mastitis samples were examined by using classical microbiological methods, followed by headspace analysis for volatile metabolites. Milk from culture-negative samples contained a lower number and amount of volatile components compared with cows with clinical mastitis. Because of variability between samples within a group, comparisons between pathogens were not sufficient for classification of the samples by univariate statistics. Therefore, an artificial neural network was trained to classify the pathogen in the milk samples based on the bacterial metabolites. The trained network differentiated milk from uninfected and infected quarters very well. When comparing pathogens, Staph. aureus produced a very different pattern of volatile metabolites compared with the other samples. Samples with coagulase-negative staphylococci and E. coli had enough dissimilarity with the other pathogens, making it possible to separate these 2 pathogens from each other and from the other samples. The 2 streptococcus species did not show significant differences between each other but could be identified as a different group from the other pathogens. Five groups can thus be identified based on the volatile bacterial metabolites: Staph. aureus, coagulase-negative staphylococci, streptococci (Strep. uberis and Strep. dysgalactiae as one group), E. coli, and uninfected quarters.
Lommano, Elena; Bertaiola, Luce; Dupasquier, Christèle
In Europe, Ixodes ricinus is the vector of many pathogens of medical and veterinary relevance, among them Borrelia burgdorferi sensu lato and tick-borne encephalitis virus, which have been the subject of numerous investigations. Less is known about the occurrence of emerging tick-borne pathogens like Rickettsia spp., Babesia spp., “Candidatus Neoehrlichia mikurensis,” and Anaplasma phagocytophilum in questing ticks. In this study, questing nymph and adult I. ricinus ticks were collected at 11 sites located in Western Switzerland. A total of 1,476 ticks were analyzed individually for the simultaneous presence of B. burgdorferi sensu lato, Rickettsia spp., Babesia spp., “Candidatus Neoehrlichia mikurensis,” and A. phagocytophilum. B. burgdorferi sensu lato, Rickettsia spp., and “Candidatus Neoehrlichia mikurensis” were detected in ticks at all sites with global prevalences of 22.5%, 10.2%, and 6.4%, respectively. Babesia- and A. phagocytophilum-infected ticks showed a more restricted geographic distribution, and their prevalences were lower (1.9% and 1.5%, respectively). Species rarely reported in Switzerland, like Borrelia spielmanii, Borrelia lusitaniae, and Rickettsia monacensis, were identified. Infections with more than one pathogenic species, involving mostly Borrelia spp. and Rickettsia helvetica, were detected in 19.6% of infected ticks. Globally, 34.2% of ticks were infected with at least one pathogen. The diversity of tick-borne pathogens detected in I. ricinus in this study and the frequency of coinfections underline the need to take them seriously into consideration when evaluating the risks of infection following a tick bite. PMID:22522688
Jori, F; Godfroid, J; Michel, A L; Potts, A D; Jaumally, M R; Sauzier, J; Roger, M
A population of approximately 70,000 rusa deer (Cervus timorensis russa) represents the most important mammal species reared for food on the island of Mauritius, being the main source of red meat for the local population. However, very limited information is available on the circulation of pathogens affecting the productivity and health of this species. To produce baseline data on the circulation of infectious pathogens in rusa deer under production, a serological survey and/or direct pathogen detection for six selected infectious diseases was undertaken in 2007 in a sample of 53% of the herds reared in semi-free-ranging conditions in hunting estates. Seropositive results were recorded for Johne's disease with an indirect ELISA test (1.7%, n = 351), heartwater with an immunofluorescence antibody test (IFAT) (95.5%, n = 178) and leptospirosis with a Microscopic Agglutination Test (MAT) (25.9%, n = 363). Significant associations were found between seroprevalence to some of the leptospiral serogroups detected (Tarassovi, Pomona, Sejroe and Mini) and age of the animals, animal density or location of the estates (being more prevalent in hotter and more humid areas). In addition, Mycobacterium bovis and M. avium subspecies paratuberculosis were confirmed in two deer carcasses by culture and PCR, respectively. No antibodies against Brucella spp. nor Rift Valley Fever virus were detected with the use of respective indirect ELISA's. The results obtained suggest that the population of rusa deer from Mauritius is exposed to a wide range of pathogens which may affect their productivity. In addition, the results highlight the potential public health risks incurred by deer industry workers and consumers. This survey fills an important gap in knowledge regarding the health of tropical deer meat in Mauritius and justifies the need to implement more regular surveys of selected pathogens in the deer population. © 2013 Blackwell Verlag GmbH.
We constructed a new real-time PCR method to detect causative pathogens in cerebrospinal fluid (CSF) from patient due to bacterial meningitis. The eight pathogens targeted in the PCR are Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus agalactiae, Staphylococcus aurues, Neisseria meningitides, Listeria monocytogenes, Esherichia coli, and Mycoplasma pneumoniae. The total time from DNA extraction from CSF to PCR analysis was 1.5 hour. The pathogens were detected in 72% of the CSF samples (n=115) by real-time PCR, but in only 48% by culture, although the microorganisms were completely concordant. The detection rate of pathogens with PCR was significantly better than that with cultures in patients with antibiotic administration.In conclusion, detection with real-time PCR is useful for rapidly identifying the causative pathogens of meningitis and for examining the clinical course of chemotherapy.
Disease pathways form overlapping networks, and hub proteins represent attractive targets for broad-spectrum drugs. Using bacterial toxins as a proof of concept, we describe a new approach of discovering broad-spectrum therapies capable of inhibiting host proteins that mediate multiple pathogenic pa...
Allocati, N; Petrucci, A G; Di Giovanni, P; Masulli, M; Di Ilio, C; De Laurenzi, V
Bats are natural reservoir hosts and sources of infection of several microorganisms, many of which cause severe human diseases. Because of contact between bats and other animals, including humans, the possibility exists for additional interspecies transmissions and resulting disease outbreaks. The purpose of this article is to supply an overview on the main pathogens isolated from bats that have the potential to cause disease in humans. PMID:27551536
Schlievert, Patrick M; Merriman, Joseph A; Salgado-Pabón, Wilmara; Mueller, Elizabeth A; Spaulding, Adam R; Vu, Bao G; Chuang-Smith, Olivia N; Kohler, Petra L; Kirby, John R
Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents.
Liu, Xiang-Ye; Gong, Xiang-Yao; Zheng, Chen; Song, Qi-Yuan; Chen, Ting; Wang, Jing; Zheng, Jie; Deng, Hong-Kuan; Zheng, Kui-Yang
Ticks are able to transmit various pathogens-viruses, bacteria, and parasites-to their host during feeding. Several molecular epidemiological surveys have been performed to evaluate the risk of tick-borne pathogens in China, but little is known about pathogens circulating in ticks from eastern China. Therefore, this study aimed to investigate the presence of bacteria and parasites in ticks collected from Xuzhou, a 11258km 2 region in eastern China. In the present study, ticks were collected from domestic goats and grasses in urban districts of Xuzhou region from June 2015 to July 2016. After tick species identification, the presence of tick-borne bacterial and parasitic pathogens, including Anaplasma phagocytophilum, Borrelia burgdorferi, Rickettsia sp., Bartonella sp., Babesia sp., and Theileria sp., was established via conventional or nested polymerase chain reaction assays (PCR) and sequence analysis. Finally, a total of 500 questing adult ticks, identified as Haemaphysalis longicornis, were investigated. Among them, 28/500 tick samples (5.6%) were infected with A. phagocytophilum, and 23/500 (4.6%) with Theileria luwenshuni, whereas co-infection with these pathogens was detected in only 1/51 (2%) of all infected ticks. In conclusion, H. longicornis is the dominant tick species in the Xuzhou region and plays an important role in zoonotic pathogen transmission. Both local residents and animals are at a significant risk of exposure to anaplasmosis and theileriosis, due to the high rates of A. phagocytophilum and T. luwenshuni tick infection. Copyright © 2016 Elsevier B.V. All rights reserved.
Krishnamurthy, Malathy; Moore, Richard T; Rajamani, Sathish; Panchal, Rekha G
The emergence and prevalence of multidrug resistant (MDR) pathogenic bacteria poses a serious threat to human and animal health globally. Nosocomial infections and common ailments such as pneumonia, wound, urinary tract, and bloodstream infections are becoming more challenging to treat due to the rapid spread of MDR pathogenic bacteria. According to recent reports by the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC), there is an unprecedented increase in the occurrence of MDR infections worldwide. The rise in these infections has generated an economic strain worldwide, prompting the WHO to endorse a global action plan to improve awareness and understanding of antimicrobial resistance. This health crisis necessitates an immediate action to target the underlying mechanisms of drug resistance in bacteria. The advent of new bacterial genome engineering and synthetic biology (SB) tools is providing promising diagnostic and treatment plans to monitor and treat widespread recalcitrant bacterial infections. Key advances in genetic engineering approaches can successfully aid in targeting and editing pathogenic bacterial genomes for understanding and mitigating drug resistance mechanisms. In this review, we discuss the application of specific genome engineering and SB methods such as recombineering, clustered regularly interspaced short palindromic repeats (CRISPR), and bacterial cell-cell signaling mechanisms for pathogen targeting. The utility of these tools in developing antibacterial strategies such as novel antibiotic production, phage therapy, diagnostics and vaccine production to name a few, are also highlighted. The prevalent use of antibiotics and the spread of MDR bacteria raise the prospect of a post-antibiotic era, which underscores the need for developing novel therapeutics to target MDR pathogens. The development of enabling SB technologies offers promising solutions to deliver safe and effective antibacterial therapies.
Gottschalk, Marcelo; Xu, Jianguo; Calzas, Cynthia; Segura, Mariela
Infections caused by Streptococcus suis are considered a global and an economical problem in the swine industry. Moreover, S. suis is an agent of zoonosis that afflicts people in close contact with infected pigs or pork-derived products. Although sporadic cases of S. suis infections in humans (mainly meningitis) have been reported during the last 40 years, a large outbreak due to this pathogen emerged in the summer of 2005 in China. The severity of the infection in humans during the outbreak, such as a shorter incubation time, more rapid disease progression and higher rate of mortality, attracted a lot of attention from the scientific community and the general press. In fact, the number of publications on S. suis (including the number of reported human cases) has significantly increased during recent years. In this article we critically review the present knowledge on S. suis infection in humans, we discuss the hypotheses that may explain the 2005 outbreak and the repercussion of such an episode on the scientific community.
Cui, Haitao; Xiang, Tingting; Zhou, Jian-Min
Phytopathogenic bacteria inject an array of effector proteins into host cells to alter host physiology and assist the infection process. Some of these effectors can also trigger disease resistance as a result of recognition in the plant cell by cytoplasmic immune receptors. In addition to effector-triggered immunity, plants immunity can be triggered upon the detection of Pathogen/Microbe-Associated Molecular Patterns by surface-localized immune receptors. Recent progress indicates that many bacterial effector proteins use a variety of biochemical properties to directly attack key components of PAMP-triggered immunity and effector-triggered immunity, providing new insights into the molecular basis of plant innate immunity. Emerging evidence indicate that the evolution of disease resistance in plants is intimately linked to the mechanism by which bacterial effectors promote parasitism. This review focuses on how these studies have conceptually advanced our understanding of plant-pathogen interactions.
Block, Anna; Schmelz, Eric; O'Donnell, Phillip J; Jones, Jeffrey B; Klee, Harry J
Recent studies on the interactions between plants and pathogenic microorganisms indicate that the processes of disease symptom development and pathogen growth can be uncoupled. Thus, in many instances, the symptoms associated with disease represent an active host response to the presence of a pathogen. These host responses are frequently mediated by phytohormones. For example, ethylene and salicylic acid (SA) mediate symptom development but do not influence bacterial growth in the interaction between tomato (Lycopersicon esculentum) and virulent Xanthomonas campestris pv vesicatoria (Xcv). It is not apparent why extensive tissue death is integral to a defense response if it does not have the effect of limiting pathogen proliferation. One possible function for this hormone-mediated response is to induce a systemic defense response. We therefore assessed the systemic responses of tomato to Xcv. SA- and ethylene-deficient transgenic lines were used to investigate the roles of these phytohormones in systemic signaling. Virulent and avirulent Xcv did induce a systemic response as evidenced by expression of defense-associated pathogenesis-related genes in an ethylene- and SA-dependent manner. This systemic response reduced cell death but not bacterial growth during subsequent challenge with virulent Xcv. This systemic acquired tolerance (SAT) consists of reduced tissue damage in response to secondary challenge with a virulent pathogen with no effect upon pathogen growth. SAT was associated with a rapid ethylene and pathogenesis-related gene induction upon challenge. SAT was also induced by infection with Pseudomonas syringae pv tomato. These data show that SAT resembles systemic acquired resistance without inhibition of pathogen growth.
Wei, Feng; Song, Mingxin; Liu, Huanhuan; Wang, Bo; Wang, Shuchao; Wang, Zedong; Ma, Hongyu; Li, Zhongyu; Zeng, Zheng; Qian, Jun; Liu, Quan
Tick-borne diseases are considered as emerging infectious diseases in humans and animals in China. In this study, Ixodes persulcatus (n = 1699), Haemaphysalis concinna (n = 412), Haemaphysalis longicornis (n = 390), Dermacentor nuttalli (n = 253), and Dermacentor silvarum (n = 204) ticks were collected by flagging from northeastern China, and detected for infection with Anaplasma, Ehrlichia, Babesia, and Hepatozoon spp. by using nested polymerase chain reaction assays and sequencing analysis. Anaplasma phagocytophilum was detected in all tick species, i.e., I. persulcatus (9.4%), H. longicornis (1.9%), H. concinna (6.5%), D. nuttalli (1.7%), and D. silvarum (2.3%); Anaplasma bovis was detected in H. longicornis (0.3%) and H. concinna (0.2%); Ehrlichia muris was detected in I. persulcatus (2.5%) and H. concinna (0.2%); Candidatus Neoehrlichia mikurensis was only detected in I. persulcatus (0.4%). The Ehrlichia variant (GenBank access number KU921424), closely related to Ehrlichia ewingii, was found in H. longicornis (0.8%) and H. concinna (0.2%). I. persulcatus was infected with Babesia venatorum (1.2%), Babesia microti (0.6%), and Babesia divergens (0.6%). Additionally, four Babesia sequence variants (GenBank access numbers 862303–862306) were detected in I. persulcatus, H. longicornis, and H. concinna, which belonged to the clusters formed by the parasites of dogs, sheep, and cattle (B. gibsoni, B. motasi, and B. crassa). Two Hepatozoon spp. (GenBank access numbers KX016028 and KX016029) associated with hepatozoonosis in Japanese martens were found in the collected ticks (0.1–3.1%). These findings showed the genetic variability of Anaplasma, Ehrlichia, Babesia, and Hepatozoon spp. circulating in ticks in northeastern China, highlighting the necessity for further research of these tick-associated pathogens and their role in human and animal diseases. PMID:27965644
Griffin, Dee; Chengappa, M M; Kuszak, Jennifer; McVey, D Scott
Pneumonia caused by the bacterial pathogens discussed in this article is the most significant cause of morbidity and mortality of the BRDC. Most of these infectious bacteria are not capable of inducing significant disease without the presence of other predisposing environmental factors, physiologic stressors, or concurrent infections. Mannheimia haemolytica is the most common and serious of these bacterial agents and is therefore also the most highly characterized. There are other important bacterial pathogens of BRD, such as Pasteurella multocida, Histophulus somni, and Mycoplasma bovis. Mixed infections with these organisms do occur. These pathogens have unique and common virulence factors but the resulting pneumonic lesions may be similar. Although the amount and quality of research associated with BRD has increased, vaccination and therapeutic practices are not fully successful. A greater understanding of the virulence mechanisms of the infecting bacteria and pathogenesis of pneumonia, as well as the characteristics of the organisms that allow tissue persistence, may lead to improved management, therapeutics, and vaccines. Copyright 2010 Elsevier Inc. All rights reserved.
Serruto, Davide; Serino, Laura; Masignani, Vega; Pizza, Mariagrazia
Bacterial infectious diseases remain the single most important threat to health worldwide. Although conventional vaccinology approaches were successful in conferring protection against several diseases, they failed to provide efficacious solutions against many others. The advent of whole-genome sequencing changed the way to think about vaccine development, enabling the targeting of possible vaccine candidates starting from the genomic information of a single bacterial isolate, with a process named reverse vaccinology. As the genomic era progressed, reverse vaccinology has evolved with a pan-genome approach and multi-strain genome analysis became fundamental for the design of universal vaccines. This review describes the applications of genome-based approaches in the development of new vaccines against bacterial pathogens.
Castillo-Torres, Keisha Y.; Garraud, Nicolas; Arnold, David P.; McLamore, Eric S.
Despite strict regulations to control the presence of human pathogens in our food supply, recent foodborne outbreaks have heightened public concern about food safety and created urgency to improve methods for pathogen detection. Herein we explore a potentially portable, low-cost system that uses magnetic microdiscs for the detection of bacterial pathogens in liquid samples. The system operates by optically measuring the rotational dynamics of suspended magnetic microdiscs functionalized with pathogen-binding aptamers. The soft ferromagnetic (Ni80Fe20) microdiscs exhibit a closed magnetic spin arrangement (i.e. spin vortex) with zero magnetic stray field, leading to no disc agglomeration when in free suspension. With very high surface area for functionalization and volumes 10,000x larger than commonly used superparamagnetic nanoparticles, these 1.5-μm-diameter microdiscs are well suited for tagging, trapping, actuating, or interrogating bacterial targets. This work reports a wafer-level microfabrication process for fabrication of 600 million magnetic microdiscs per substrate and measurement of their rotational dynamics response. Additionally, the biofunctionalization of the microdiscs with DNA aptamers, subsequent binding to E. coli bacteria, and their magnetic manipulation is reported.
Oral samples, including saliva, offer an attractive alternative to serum or urine for diagnostic testing. This is particularly true for point-of-use detection systems. The various types of oral samples that have been reported in the literature are presented here along with the wide variety of analytes that have been measured in saliva and other oral samples. The paper focuses on utilizing point-detection of infectious disease agents, and presents work from our group on a rapid test for multiple bacterial and viral pathogens by monitoring a series of targets. It is thus possible in a single oral sample to identify multiple pathogens based on specific antigens, nucleic acids, and host antibodies to those pathogens. The value of such a technology for detecting agents of bioterrorism at remote sites is discussed.
Sohn, Miryeong; Himmelsbach, David S; Barton, Franklin E; Fedorka-Cray, Paula J
This study deals with the rapid detection and differentiation of Escherichia coli, Salmonella, and Campylobacter, which are the most commonly identified commensal and pathogenic bacteria in foods, using fluorescence spectroscopy and multivariate analysis. Each bacterial sample cultured under controlled conditions was diluted in physiologic saline for analysis. Fluorescence spectra were collected over a range of 200-700 nm with 0.5 nm intervals on the PerkinElmer Fluorescence Spectrometer. The synchronous scan technique was employed to find the optimum excitation (lambda(ex)) and emission (lambda(em)) wavelengths for individual bacteria with the wavelength interval (Deltalambda) being varied from 10 to 200 nm. The synchronous spectra and two-dimensional plots showed two maximum lambda(ex) values at 225 nm and 280 nm and one maximum lambda(em) at 335-345 nm (lambda(em) = lambda(ex) + Deltalambda), which correspond to the lambda(ex) = 225 nm, Deltalambda = 110-120 nm, and lambda(ex) = 280 nm, Deltalambda = 60-65 nm. For all three bacterial genera, the same synchronous scan results were obtained. The emission spectra from the three bacteria groups were very similar, creating difficulty in classification. However, the application of principal component analysis (PCA) to the fluorescence spectra resulted in successful classification of the bacteria by their genus as well as determining their concentration. The detection limit was approximately 10(3)-10(4) cells/mL for each bacterial sample. These results demonstrated that fluorescence spectroscopy, when coupled with PCA processing, has the potential to detect and to classify bacterial pathogens in liquids. The methodology is rapid (>10 min), inexpensive, and requires minimal sample preparation compared to standard analytical methods for bacterial detection.
Bacterial pathogens cause disease in man and animals. They have unique biological properties, which enable them to colonize mucous surfaces, penetrate them, grow in the environment of the host, inhibit or avoid host defences and damage the host. The bacterial products responsible for these five biological requirements are the determinants of pathogenicity (virulence determinants). Current knowledge comes from studies in vitro, but now interest is increasing in how bacteria behave and produce virulence determinants within the infected host. There are three aspects to elucidate: bacterial activities, the host factors that affect them and the metabolic interactions between the two. The first is relatively easy to accomplish and, recently, new methods for doing this have been devised. The second is not easy because of the complexity of the environment in vivo and its ever-changing face. Nevertheless, some information can be gained from the literature and by new methodology. The third aspect is very difficult to study effectively unless some events in vivo can be simulated in vitro. The objectives of the Discussion Meeting were to describe the new methods and to show how they, and conventional studies, are revealing the activities of bacterial pathogens in vivo. This paper sets the scene by raising some questions and suggesting, with examples, how they might be answered. Bacterial growth in vivo is the primary requirement for pathogenicity. Without growth, determinants of the other four requirements are not formed. Results from the new methods are underlining this point. The important questions are as follows. What is the pattern of a developing infection and the growth rates and population sizes of the bacteria at different stages? What nutrients are present in vivo and how do they change as infection progresses and relate to growth rates and population sizes? How are these nutrients metabolized and by what bacterial mechanisms? Which bacterial processes handle
Eldridge, Matthew J G; Shenoy, Avinash R
Inflammasomes - molecular platforms for caspase-1 activation - have emerged as common hubs for a number of pathways that detect and respond to bacterial pathogens. Caspase-1 activation results in the secretion of bioactive IL-1β and IL-18 and pyroptosis, and thus launches a systemic immune and inflammatory response. In this review we discuss signal transduction leading to 'canonical' and 'non-canonical' activation of caspase-1 through the involvement of upstream caspases. Recent studies have identified a growing number of regulatory networks involving guanylate binding proteins, protein kinases, ubiquitylation and necroptosis related pathways that modulate inflammasome responses and immunity to bacterial infection. By being able to respond to extracellular, vacuolar and cytosolic bacteria, their cytosolic toxins or ligands for cell surface receptors, inflammasomes have emerged as important sentinels of infection. Copyright © 2014 Elsevier Ltd. All rights reserved.
Pudová, V; Htoutou Sedláková, M; Kolář, M
Hospital-acquired pneumonia (HAP) is one of the most serious complications in patients staying in intensive care units. This multicenter study of Czech patients with HAP aimed at assessing the clonality of bacterial pathogens causing the condition. Bacterial isolates were compared using pulsed-field gel electrophoresis. Included in this study were 330 patients hospitalized between May 1, 2013 and December 31, 2014 at departments of anesthesiology and intensive care medicine of four big hospitals in the Czech Republic. A total of 531 bacterial isolates were obtained, of which 267 were classified as etiological agents causing HAP. Similarity or identity was assessed in 231 bacterial isolates most frequently obtained from HAP patients. Over the study period, no significant clonal spread was noted. Most isolates were unique strains, and the included HAP cases may therefore be characterized as mostly endogenous. Yet there were differences in species and potential identical isolates between the participating centers. In three hospitals, Gram-negative bacteria (Enterobacteriaceae and Pseudomonas aeruginosa) prevailed as etiological agents, and Staphylococcus aureus was most prevalent in the fourth center.
Braymer, Joseph J.; Giedroc, David P.
Copper and zinc homeostasis systems in pathogenic bacteria are required to resist host efforts to manipulate the availability and toxicity of these metal ions. Central to this microbial adaptive response is the involvement of metal-trafficking and -sensing proteins that ultimately exercise control of metal speciation in the cell. Cu- and Zn-specific metalloregulatory proteins regulate the transcription of metal-responsive genes while metallochaperones and related proteins ensure that these metals are appropriately buffered by the intracellular milieu and delivered to correct intracellular targets. In this review, we summarize recent findings on how bacterial pathogens mount a metal-specific response to derail host efforts to win the “fight over metals.” PMID:24463765
Zumla, Alimuddin; Dar, Osman; Kock, Richard; Muturi, Matthew; Ntoumi, Francine; Kaleebu, Pontiano; Eusebio, Macete; Mfinanga, Sayoki; Bates, Matthew; Mwaba, Peter; Ansumana, Rashid; Khan, Mishal; Alagaili, Abdulaziz N; Cotten, Matthew; Azhar, Esam I; Maeurer, Markus; Ippolito, Giuseppe; Petersen, Eskild
The appearance of novel pathogens of humans with epidemic potential and high mortality rates have threatened global health security for centuries. Over the past few decades new zoonotic infectious diseases of humans caused by pathogens arising from animal reservoirs have included West Nile virus, Yellow fever virus, Ebola virus, Nipah virus, Lassa Fever virus, Hanta virus, Dengue fever virus, Rift Valley fever virus, Crimean-Congo haemorrhagic fever virus, severe acute respiratory syndrome coronavirus, highly pathogenic avian influenza viruses, Middle East Respiratory Syndrome Coronavirus, and Zika virus. The recent Ebola Virus Disease epidemic in West Africa and the ongoing Zika Virus outbreak in South America highlight the urgent need for local, regional and international public health systems to be be more coordinated and better prepared. The One Health concept focuses on the relationship and interconnectedness between Humans, Animals and the Environment, and recognizes that the health and wellbeing of humans is intimately connected to the health of animals and their environment (and vice versa). Critical to the establishment of a One Health platform is the creation of a multidisciplinary team with a range of expertise including public health officers, physicians, veterinarians, animal husbandry specialists, agriculturalists, ecologists, vector biologists, viral phylogeneticists, and researchers to co-operate, collaborate to learn more about zoonotic spread between animals, humans and the environment and to monitor, respond to and prevent major outbreaks. We discuss the unique opportunities for Middle Eastern and African stakeholders to take leadership in building equitable and effective partnerships with all stakeholders involved in human and health systems to take forward a 'One Health' approach to control such zoonotic pathogens with epidemic potential. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.
Gomes, Bruna Carrer; Franco, Bernadette Dora Gombossy de Melo; De Martinis, Elaine Cristina Pereira
The globalization of food supply impacts patterns of foodborne disease outbreaks worldwide, and consumers are having increased concern about microbiological food safety. In this sense, the assessment of epidemiological data of foodborne diseases in different countries has not only local impact, but it can also be of general interest, especially in the case of major global producers and exporters of several agricultural food products, such as Brazil. In this review, the most common agents of foodborne illnesses registered in Brazil will be presented, compiled mainly from official databases made available to the public. In addition, some representative examples of studies on foodborne bacterial pathogens commonly found in Brazilian foods are provided.
Razzak, Mohammad Sabri A; Al-Charrakh, Alaa H; Al-Greitty, Bara Hamid
Vaginitis, is an infectious inflammation of the vaginal mucosa, which sometimes involves the vulva. The balance of the vaginal flora is maintained by the Lactobacilli and its protective and probiotic role in treating and preventing vaginal infection by producing antagonizing compounds which are regarded as safe for humans. The aim of this study was to evaluate the protective role of Lactobacilli against common bacterial opportunistic pathogens in vaginitis and study the effects of some antibiotics on Lactobacilli isolates. In this study (110) vaginal swabs were obtained from women suffering from vaginitis who admitted to Babylon Hospital of Maternity and Paediatrics in Babylon province, Iraq. The study involved the role of intrauterine device among married women with vaginitis and also involved isolation of opportunistic bacterial isolates among pregnant and non pregnant women. This study also involved studying probiotic role of Lactobacilli by production of some defense factors like hydrogen peroxide, bacteriocin, and lactic acid. Results revealed that a total of 130 bacterial isolates were obtained. Intrauterine device was a predisposing factor for vaginitis. The most common opportunistic bacterial isolates were Staphylococcus aureus, Escherichia coli, Streptococcus agalactiae, and Klebsiella pneumoniae. All Lactobacilli were hydrogen peroxide producers while some isolates were bacteriocin producers that inhibited some of opportunistic pathogens (S. aureus, E. coli). Lactobacilli were sensitive to erythromycin while 93.3% of them were resistant to ciprofloxacin and (40%, 53.3%) of them were resistant to amoxicillin and gentamycin respectively. Results revealed that there was an inverse relationship between Lactobacilli presence and organisms causing vaginitis. This may be attributed to the production of defense factors by Lactobacilli. The types of antibiotics used to treat vaginitis must be very selective in order not to kill the beneficial bacteria
Razzak, Mohammad Sabri A.; Al-Charrakh, Alaa H.; AL-Greitty, Bara Hamid
Background: Vaginitis, is an infectious inflammation of the vaginal mucosa, which sometimes involves the vulva. The balance of the vaginal flora is maintained by the Lactobacilli and its protective and probiotic role in treating and preventing vaginal infection by producing antagonizing compounds which are regarded as safe for humans. Aim: The aim of this study was to evaluate the protective role of Lactobacilli against common bacterial opportunistic pathogens in vaginitis and study the effects of some antibiotics on Lactobacilli isolates. Materials and Methods: In this study (110) vaginal swabs were obtained from women suffering from vaginitis who admitted to Babylon Hospital of Maternity and Paediatrics in Babylon province, Iraq. The study involved the role of intrauterine device among married women with vaginitis and also involved isolation of opportunistic bacterial isolates among pregnant and non pregnant women. This study also involved studying probiotic role of Lactobacilli by production of some defense factors like hydrogen peroxide, bacteriocin, and lactic acid. Results: Results revealed that a total of 130 bacterial isolates were obtained. Intrauterine device was a predisposing factor for vaginitis. The most common opportunistic bacterial isolates were Staphylococcus aureus, Escherichia coli, Streptococcus agalactiae, and Klebsiella pneumoniae. All Lactobacilli were hydrogen peroxide producers while some isolates were bacteriocin producers that inhibited some of opportunistic pathogens (S. aureus, E. coli). Lactobacilli were sensitive to erythromycin while 93.3% of them were resistant to ciprofloxacin and (40%, 53.3%) of them were resistant to amoxicillin and gentamycin respectively. Results revealed that there was an inverse relationship between Lactobacilli presence and organisms causing vaginitis. This may be attributed to the production of defense factors by Lactobacilli. Conclusion: The types of antibiotics used to treat vaginitis must be very
McGuire, Victoria A.; Arthur, J. Simon C.
Pathogenic bacteria are detected by pattern-recognition receptors (PRRs) expressed on innate immune cells, which activate intracellular signal transduction pathways to elicit an immune response. Toll-like receptors are, perhaps, the most studied of the PRRs and can activate the mitogen-activated protein kinase (MAPK) and Nuclear Factor-κB (NF-κB) pathways. These pathways are critical for mounting an effective immune response. In order to evade detection and promote virulence, many pathogens subvert the host immune response by targeting components of these signal transduction pathways. This mini-review highlights the diverse mechanisms that bacterial pathogens have evolved to manipulate the innate immune response, with a particular focus on those that target MAPK and NF-κB signaling pathways. Understanding the elaborate strategies that pathogens employ to subvert the immune response not only highlights the importance of these proteins in mounting effective immune responses, but may also identify novel approaches for treatment or prevention of infection. PMID:26648936
Dhama, K; Rajagunalan, S; Chakraborty, S; Verma, A K; Kumar, A; Tiwari, R; Kapoor, S
The term food borne diseases or food-borne illnesses or more commonly food poisoning are used to denote gastrointestinal complications that occur following recent consumption of a particular food or drink. Millions of people suffer worldwide every year and the situation is quiet grave in developing nations creating social and economic strain. The food borne pathogens include various bacteria viz., Salmonella, Campylobacter, Escherichia coli, Listeria monocytogenes, Yersinia enterocolitica, Staphylococcus, Arcobacter, Clostridium perfringens, Cl. botulinum and Bacillus cereus and helminths viz., Taenia. They also include protozoa viz., Trichinella, Sarcocystis, Toxoplasma gondii and Cryptosporidium parvum. The zoonotic potential and the ability to elaborate toxins by many of the microbes causing fatal intoxication are sufficient to understand the seriousness of the situation. The viral agents being host specific their transmission to humans through food of animal origin is not yet confirmed although these animal viruses are similar to that of viruses infecting human. Food-borne bacteria; protozoa and helminthes have complex distribution pattern in the environment and inside the host system. This along with complexity of the maintenance chain and life cycle (of parasites) has made it difficult for epidemiologist and diagnostician to undertake any immediate safety measures against them. Serological and molecular diagnostic tests viz. ELISA, Latex agglutination test, Lateral flow assays, Immunomagnetic separation assays, molecular assays viz. Polymerase Chain Reaction (PCR), multiplex PCR, immuno-PCR, Realtime PCR, Random Amplified Polymorphic DNA (RAPD)-PCR, DNA microarrays and probes are widely used. Along with these LAMP assays, Capillary Electrophoresis-Single Strand Confirmation polymorphism (CE-SSCP); Flow cytometry, FISH, Biosensors, Direct epifluorescent filter technique, nanotechnology based methods and sophisticated tools (ultrasonography, magnetic resonance
Aijuka, Matthew; Charimba, George; Hugo, Celia J; Buys, Elna M
The study aimed to compare the bacteriological quality of an urban and rural irrigation water source. Bacterial counts, characterization, identification and diversity of aerobic bacteria were determined. Escherichia coli isolated from both sites was subjected to antibiotic susceptibility testing, virulence gene (Stx1/Stx2 and eae) determination and (GTG)5 Rep-PCR fingerprinting. Low mean monthly counts for aerobic spore formers, anaerobic spore formers and Staphylococcus aureus were noted although occasional spikes were observed. The most prevalent bacterial species at both sites were Bacillus spp., E. coli and Enterobacter spp. In addition, E. coli and Bacillus spp. were most prevalent in winter and summer respectively. Resistance to at least one antibiotic was 84% (rural) and 83% (urban). Highest resistance at both sites was to cephalothin and ampicillin. Prevalence of E. coli possessing at least one virulence gene (Stx1/Stx2 and eae) was 15% (rural) and 42% (urban). All (rural) and 80% (urban) of E. coli possessing virulence genes showed antibiotic resistance. Complete genetic relatedness (100%) was shown by 47% of rural and 67% of urban E. coli isolates. Results from this study show that surface irrigation water sources regardless of geographical location and surrounding land-use practices can be reservoirs of similar bacterial pathogens.
Wang, L-F; Crameri, G
Zoonotic diseases are infectious diseases that are naturally transmitted from vertebrate animals to humans and vice versa. They are caused by all types of pathogenic agents, including bacteria, parasites, fungi, viruses and prions. Although they have been recognised for many centuries, their impact on public health has increased in the last few decades due to a combination of the success in reducing the spread of human infectious diseases through vaccination and effective therapies and the emergence of novel zoonotic diseases. It is being increasingly recognised that a One Health approach at the human-animal-ecosystem interface is needed for effective investigation, prevention and control of any emerging zoonotic disease. Here, the authors will review the drivers for emergence, highlight some of the high-impact emerging zoonotic diseases of the last two decades and provide examples of novel One Health approaches for disease investigation, prevention and control. Although this review focuses on emerging zoonotic viral diseases, the authors consider that the discussions presented in this paper will be equally applicable to emerging zoonotic diseases of other pathogen types.
Roxas, Jennifer Lising; Viswanathan, V K
The passive and regulated movement of ions, solutes, and water via spaces between cells of the epithelial monolayer plays a critical role in the normal intestinal functioning. This paracellular pathway displays a high level of structural and functional specialization, with the membrane-spanning complexes of the tight junctions, adherens junctions, and desmosomes ensuring its integrity. Tight junction proteins, like occludin, tricellulin, and the claudin family isoforms, play prominent roles as barriers to unrestricted paracellular transport. The past decade has witnessed major advances in our understanding of the architecture and function of epithelial tight junctions. While it has been long appreciated that microbes, notably bacterial and viral pathogens, target and disrupt junctional complexes and alter paracellular permeability, the precise mechanisms remain to be defined. Notably, renewed efforts will be required to interpret the available data on pathogen-mediated barrier disruption in the context of the most recent findings on tight junction structure and function. While much of the focus has been on pathogen-induced dysregulation of junctional complexes, commensal microbiota and their products may influence paracellular permeability and contribute to the normal physiology of the gut. Finally, microbes and their products have become important tools in exploring host systems, including the junctional properties of epithelial cells. © 2018 American Physiological Society. Compr Physiol 8:823-842, 2018. Copyright © 2018 American Physiological Society. All rights reserved.
Deep, Antariksh; Chaudhary, Uma; Gupta, Varsha
Quorum sensing in prokaryotic biology refers to the ability of a bacterium to sense information from other cells in the population when they reach a critical concentration (i.e. a Quorum) and communicate with them. The “language” used for this intercellular communication is based on small, self-generated signal molecules called as autoinducers. Quorum sensing is thought to afford pathogenic bacteriaa mechanism to minimize host immune responses by delaying theproduction of tissue-damaging virulence factors until sufficientbacteria have amassed and are prepared to overwhelm host defensemechanisms and establish infection. Quorum sensing systems are studied in a large number of gram-negative bacterial species belonging to α, β, and γ subclasses of proteobacteria. Among the pathogenic bacteria, Pseudomonas aeruginosa is perhaps the best understood in terms of the virulence factors regulated and the role the Quorum sensing plays in pathogenicity. Presently, Quorum sensing is considered as a potential novel target for antimicrobial therapy to control multi/all drug-resistant infections. This paper reviews Quorum sensing in gram positive and gram negative bacteria and its role in biofilm formation. PMID:21701655
Andersson, Martin O; Tolf, Conny; Tamba, Paula; Stefanache, Mircea; Radbea, Gabriel; Frangoulidis, Dimitrios; Tomaso, Herbert; Waldenström, Jonas; Dobler, Gerhard; Chitimia-Dobler, Lidia
Ticks are transmitting a wide range of bacterial pathogens that cause substantial morbidity and mortality in domestic animals. The full pathogen burden transmitted by tick vectors is incompletely studied in many geographical areas, and extensive studies are required to fully understand the diversity and distribution of pathogens transmitted by ticks. We sampled 824 ticks of 11 species collected in 19 counties in Romania. Ticks were collected mainly from dogs, but also from other domestic and wild animals, and were subjected to molecular screening for pathogens. Rickettsia spp. was the most commonly detected pathogen, occurring in 10.6% (87/824) of ticks. Several species were detected: Rickettsia helvetica, R. raoultii, R. massiliae, R. monacensis, R. slovaca and R. aeschlimannii. A single occurrence of the zoonotic bacterium Bartonella vinsonii berkhoffii was detected in a tick collected from a dog. Anaplasma phagocytophilum occurred in four samples, and sequences similar to Anaplasma marginale/ovis were abundant in ticks from ruminants. In addition, molecular screening showed that ticks from dogs were carrying an Ehrlichia species identical to the HF strain as well as the enigmatic zoonotic pathogen "Candidatus Neoehrlichia mikurensis". An organism similar to E. chaffeensis or E. muris was detected in an Ixodes ricinus collected from a fox. We describe an abundant diversity of bacterial tick-borne pathogens in ticks collected from animal hosts in Romania, both on the level of species and genotypes/strains within these species. Several findings were novel for Romania, including Bartonella vinsonii subsp. berkhoffii that causes bacteremia and endocarditis in dogs. "Candidatus Neoehrlichia mikurensis" was detected in a tick collected from a dog. Previously, a single case of infection in a dog was diagnosed in Germany. The results warrant further studies on the consequences of tick-borne pathogens in domestic animals in Romania.
Karasartova, Djursun; Gureser, Ayse Semra; Gokce, Tuncay; Celebi, Bekir; Yapar, Derya; Keskin, Adem; Celik, Selim; Ece, Yasemin; Erenler, Ali Kemal; Usluca, Selma; Mumcuoglu, Kosta Y.
Background Tick-borne diseases are increasing all over the word, including Turkey. The aim of this study was to determine the bacterial and protozoan vector-borne pathogens in ticks infesting humans in the Corum province of Turkey. Methodology/Principal findings From March to November 2014 a total of 322 ticks were collected from patients who attended the local hospitals with tick bites. Ticks were screened by real time-PCR and PCR, and obtained amplicons were sequenced. The dedected tick was belonging to the genus Hyalomma, Haemaphysalis, Rhipicephalus, Dermacentor and Ixodes. A total of 17 microorganism species were identified in ticks. The most prevalent Rickettsia spp. were: R. aeschlimannii (19.5%), R. slovaca (4.5%), R. raoultii (2.2%), R. hoogstraalii (1.9%), R. sibirica subsp. mongolitimonae (1.2%), R. monacensis (0.31%), and Rickettsia spp. (1.2%). In addition, the following pathogens were identified: Borrelia afzelii (0.31%), Anaplasma spp. (0.31%), Ehrlichia spp. (0.93%), Babesia microti (0.93%), Babesia ovis (0.31%), Babesia occultans (3.4%), Theileria spp. (1.6%), Hepatozoon felis (0.31%), Hepatozoon canis (0.31%), and Hemolivia mauritanica (2.1%). All samples were negative for Francisella tularensis, Coxiella burnetii, Bartonella spp., Toxoplasma gondii and Leishmania spp. Conclusions/Significance Ticks in Corum carry a large variety of human and zoonotic pathogens that were detected not only in known vectors, but showed a wider vector diversity. There is an increase in the prevalence of ticks infected with the spotted fever group and lymphangitis-associated rickettsiosis, while Ehrlichia spp. and Anaplasma spp. were reported for the first time from this region. B. microti was detected for the first time in Hyalomma marginatum infesting humans. The detection of B. occultans, B. ovis, Hepatozoon spp., Theileria spp. and Hemolivia mauritanica indicate the importance of these ticks as vectors of pathogens of veterinary importance, therefore patients with
Karasartova, Djursun; Gureser, Ayse Semra; Gokce, Tuncay; Celebi, Bekir; Yapar, Derya; Keskin, Adem; Celik, Selim; Ece, Yasemin; Erenler, Ali Kemal; Usluca, Selma; Mumcuoglu, Kosta Y; Taylan-Ozkan, Aysegul
Tick-borne diseases are increasing all over the word, including Turkey. The aim of this study was to determine the bacterial and protozoan vector-borne pathogens in ticks infesting humans in the Corum province of Turkey. From March to November 2014 a total of 322 ticks were collected from patients who attended the local hospitals with tick bites. Ticks were screened by real time-PCR and PCR, and obtained amplicons were sequenced. The dedected tick was belonging to the genus Hyalomma, Haemaphysalis, Rhipicephalus, Dermacentor and Ixodes. A total of 17 microorganism species were identified in ticks. The most prevalent Rickettsia spp. were: R. aeschlimannii (19.5%), R. slovaca (4.5%), R. raoultii (2.2%), R. hoogstraalii (1.9%), R. sibirica subsp. mongolitimonae (1.2%), R. monacensis (0.31%), and Rickettsia spp. (1.2%). In addition, the following pathogens were identified: Borrelia afzelii (0.31%), Anaplasma spp. (0.31%), Ehrlichia spp. (0.93%), Babesia microti (0.93%), Babesia ovis (0.31%), Babesia occultans (3.4%), Theileria spp. (1.6%), Hepatozoon felis (0.31%), Hepatozoon canis (0.31%), and Hemolivia mauritanica (2.1%). All samples were negative for Francisella tularensis, Coxiella burnetii, Bartonella spp., Toxoplasma gondii and Leishmania spp. Ticks in Corum carry a large variety of human and zoonotic pathogens that were detected not only in known vectors, but showed a wider vector diversity. There is an increase in the prevalence of ticks infected with the spotted fever group and lymphangitis-associated rickettsiosis, while Ehrlichia spp. and Anaplasma spp. were reported for the first time from this region. B. microti was detected for the first time in Hyalomma marginatum infesting humans. The detection of B. occultans, B. ovis, Hepatozoon spp., Theileria spp. and Hemolivia mauritanica indicate the importance of these ticks as vectors of pathogens of veterinary importance, therefore patients with a tick infestation should be followed for a variety of pathogens
Lee, Soo Youn; Lee, Jiho; Lee, Hye Sun; Chang, Jeong Ho
We report rapid and accurate pathogen detection by coupling with high efficiency magnetic separation of pathogen by Ni(2+)-heterogeneous magnetic mesoporous silica (Ni-HMMS) and real time-polymerase chain reaction (RT-PCR) technique. Ni-HMMS was developed with a significant incorporation of Fe particles within the silica mesopores by programmed thermal hydrogen reaction and functionalized with Ni(2+) ion on the surface by the wet impregnation process. High abundant Ni(2+) ions on the Ni-HMMS surface were able to assemble with cell wall component protein NikA (nickel-binding membrane protein), which contains several pathogenic bacteria including Escherichia coli O157:H7. NikA protein expression experiment showed the outstanding separation rate of the nikA gene-overexpressed E. coli (pSY-Nik) when comparing with wild-type E. coli (44.5 ± 13%) or not over-expressed E. coli (pSY-Nik) (53.2 ± 2.7%). Moreover, Ni-HMMS showed lower obstacle effect by large reaction volume (10 mL) than spherical core/shell-type silica magnetic nanoparticles functionalized with Ni(2+) (ca. 40 nm-diameters). Finally, the Ni-HMMS was successfully assessed to separate pathogenic E. coli O157:H7 and applied to direct and rapid RT-PCR to quantitative detection at ultralow concentration (1 Log10 cfu mL(-1)) in the real samples (milk and Staphylococcus aureus culture broth) without bacterial amplification and DNA extraction step. © 2013 Elsevier B.V. All rights reserved.
Abba, Yusuf; Ilyasu, Yusuf Maina; Noordin, Mustapha Mohamed
Captivity of non-venomous snakes such as python and boa are common in zoos, aquariums and as pets in households. Poor captivity conditions expose these reptiles to numerous pathogens which may result in disease conditions. The purpose of this study was to investigate the common bacteria isolated from necropsied captive snakes in Malaysia over a five year period. A total of 27 snake carcasses presented for necropsy at the Universiti Putra Malaysia (UPM) were used in this survey. Samples were aseptically obtained at necropsy from different organs/tissues (lung, liver, heart, kindey, oesophagus, lymph node, stomach, spinal cord, spleen, intestine) and cultured onto 5% blood and McConkey agar, respectively. Gram staining, morphological evaluation and biochemical test such as oxidase, catalase and coagulase were used to tentatively identify the presumptive bacterial isolates. Pythons had the highest number of cases (81.3%) followed by anaconda (14.8%) and boa (3.7%). Mixed infection accounted for 81.5% in all snakes and was highest in pythons (63%). However, single infection was only observed in pythons (18.5%). A total of 82.7%, 95.4% and 100% of the bacterial isolates from python, anaconda and boa, respectively were gram negative. Aeromonas spp was the most frequently isolated bacteria in pythons and anaconda with incidences of 25 (18%) and 8 (36.6%) with no difference (p > 0.05) in incidence, respectively, while Salmonella spp was the most frequently isolated in boa and significantly higher (p < 0.05) than in python and anaconda. Bacteria species were most frequently isolated from the kidney of pythons 35 (25.2%), intestines of anacondas 11 (50%) and stomach of boa 3 (30%). This study showed that captive pythons harbored more bacterial species than anaconda or boa. Most of the bacterial species isolated from these snakes have public health importance and have been incriminated in human infections worldwide. Copyright © 2017 Elsevier Ltd. All rights reserved.
Wilkes, Graham; Ruecker, Norma J.; Neumann, Norman F.; Gannon, Victor P. J.; Jokinen, Cassandra; Sunohara, Mark; Topp, Edward; Pintar, Katarina D. M.; Edge, Thomas A.
Nearly 690 raw surface water samples were collected during a 6-year period from multiple watersheds in the South Nation River basin, Ontario, Canada. Cryptosporidium oocysts in water samples were enumerated, sequenced, and genotyped by detailed phylogenetic analysis. The resulting species and genotypes were assigned to broad, known host and human infection risk classes. Wildlife/unknown, livestock, avian, and human host classes occurred in 21, 13, 3, and <1% of sampled surface waters, respectively. Cryptosporidium andersoni was the most commonly detected livestock species, while muskrat I and II genotypes were the most dominant wildlife genotypes. The presence of Giardia spp., Salmonella spp., Campylobacter spp., and Escherichia coli O157:H7 was evaluated in all water samples. The greatest significant odds ratios (odds of pathogen presence when host class is present/odds of pathogen presence when host class is absent) for Giardia spp., Campylobacter spp., and Salmonella spp. in water were associated, respectively, with livestock (odds ratio of 3.1), avian (4.3), and livestock (9.3) host classes. Classification and regression tree analyses (CART) were used to group generalized host and human infection risk classes on the basis of a broad range of environmental and land use variables while tracking cooccurrence of zoonotic pathogens in these groupings. The occurrence of livestock-associated Cryptosporidium was most strongly related to agricultural water pollution in the fall (conditions also associated with elevated odds ratios of other zoonotic pathogens occurring in water in relation to all sampling conditions), whereas wildlife/unknown sources of Cryptosporidium were geospatially associated with smaller watercourses where urban/rural development was relatively lower. Conditions that support wildlife may not necessarily increase overall human infection risks associated with Cryptosporidium since most Cryptosporidium genotypes classed as wildlife in this study (e
Goyette-Desjardins, Guillaume; Auger, Jean-Philippe; Xu, Jianguo; Segura, Mariela; Gottschalk, Marcelo
Streptococcus suis is an important pathogen causing economic problems in the pig industry. Moreover, it is a zoonotic agent causing severe infections to people in close contact with infected pigs or pork-derived products. Although considered sporadic in the past, human S. suis infections have been reported during the last 45 years, with two large outbreaks recorded in China. In fact, the number of reported human cases has significantly increased in recent years. In this review, we present the worldwide distribution of serotypes and sequence types (STs), as determined by multilocus sequence typing, for pigs (between 2002 and 2013) and humans (between 1968 and 2013). The methods employed for S. suis identification and typing, the current epidemiological knowledge regarding serotypes and STs and the zoonotic potential of S. suis are discussed. Increased awareness of S. suis in both human and veterinary diagnostic laboratories and further establishment of typing methods will contribute to our knowledge of this pathogen, especially in regions where complete and/or recent data is lacking. More research is required to understand differences in virulence that occur among S. suis strains and if these differences can be associated with specific serotypes or STs. PMID:26038745
Naser, A M; Hossain, M J; Sazzad, H M S; Homaira, N; Gurley, E S; Podder, G; Afroj, S; Banu, S; Rollin, P E; Daszak, P; Ahmed, B-N; Rahman, M; Luby, S P
This paper explores the utility of cluster- and case-based surveillance established in government hospitals in Bangladesh to detect Nipah virus, a stage III zoonotic pathogen. Physicians listed meningo-encephalitis cases in the 10 surveillance hospitals and identified a cluster when ⩾2 cases who lived within 30 min walking distance of one another developed symptoms within 3 weeks of each other. Physicians collected blood samples from the clustered cases. As part of case-based surveillance, blood was collected from all listed meningo-encephalitis cases in three hospitals during the Nipah season (January-March). An investigation team visited clustered cases' communities to collect epidemiological information and blood from the living cases. We tested serum using Nipah-specific IgM ELISA. Up to September 2011, in 5887 listed cases, we identified 62 clusters comprising 176 encephalitis cases. We collected blood from 127 of these cases. In 10 clusters, we identified a total of 62 Nipah cases: 18 laboratory-confirmed and 34 probable. We identified person-to-person transmission of Nipah virus in four clusters. From case-based surveillance, we identified 23 (4%) Nipah cases. Faced with thousands of encephalitis cases, integrated cluster surveillance allows targeted deployment of investigative resources to detect outbreaks by stage III zoonotic pathogens in resource-limited settings.
Herasimenka, Yury; Benincasa, Monica; Mattiuzzo, Maura; Cescutti, Paola; Gennaro, Renato; Rizzo, Roberto
The interaction of two cathelicidin antimicrobial peptides, LL-37 and SMAP-29, with three bacterial polysaccharides, respectively, produced by Pseudomonas aeruginosa, Burkholderia cepacia and Klebsiella pneumoniae, was investigated to identify possible mechanisms adopted by lung pathogens to escape the action of innate immunity effectors. In vitro assays indicated that the antibacterial activity of both peptides was inhibited to a variable extent by the three polysaccharides. Circular dichroism experiments showed that these induced an alpha-helical conformation in the two peptides, with the polysaccharides from K. pneumoniae and B. cepacia showing, respectively, the highest and the lowest effect. Fluorescence measurements also indicated the presence of peptide-polysaccharide interactions. A model is proposed in which the binding of peptides to the polysaccharide molecules induces, at low polysaccharide to peptide ratios, a higher order of aggregation, due to peptide-peptide interactions. Overall, these results suggest that binding of the peptides by the polysaccharides produced by lung pathogens can contribute to the impairment of peptide-based innate defenses of airway surface.
Killiny, Nabil; Almeida, Rodrigo P P
Many bacterial plant pathogens have a gene-for-gene relationship that determines host specificity. However, there are pathogens such as the xylem-limited bacterium Xylella fastidiosa that do not carry genes considered essential for the gene-for-gene model, such as those coding for a type III secretion system and effector molecules. Nevertheless, X. fastidiosa subspecies are host specific. A comparison of symptom development and host colonization after infection of plants with several mutant strains in two hosts, grapevines and almonds, indicated that X. fastidiosa virulence mechanisms are similar in those plants. Thus, we tested if modification of gene regulation patterns, by affecting the production of a cell-cell signalling molecule (DSF), impacted host specificity in X. fastidiosa. Results show that disruption of the rpfF locus, required for DSF synthesis, in a strain incapable of causing disease in grapevines, leads to symptom development in that host. These data are indicative that the core machinery required for the colonization of grapevines is present in that strain, and that changes in gene regulation alone can lead X. fastidiosa to exploit a novel host. The study of the evolution and mechanisms of host specificity mediated by gene regulation at the genome level could lead to important insights on the emergence of new diseases. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.
Mikhail, I A; Fox, E; Haberberger, R L; Ahmed, M H; Abbatte, E A
During a survey examining the causes of diarrhea in the East African country of Djibouti, 140 bacterial pathogens were recovered from 209 diarrheal and 100 control stools. The following pathogens were isolated at comparable frequencies from both diarrheal and control stools: enteroadherent Escherichia coli (EAEC) (10.6 versus 13%), enterotoxigenic E. coli (ETEC) (11 versus 10%), enteropathogenic E. coli (EPEC) (7.7 versus 12%), Salmonella spp. (2.9 versus 3%), and Campylobacter jejuni-C. coli (3.3 versus 5%). Surprisingly, the EAEC strains isolated did not correspond to well-recognized EPEC serogroups. No Yersinia spp., enteroinvasive E. coli, or enterohemorrhagic E. coli were isolated during the course of this study. Only the following two genera were recovered from diarrheal stools exclusively: Shigella spp. (7.7%) and Aeromonas hydrophila group organisms (3.3%). Shigella flexneri was the most common Shigella species isolated. Patients with Shigella species were of a higher average age than were controls (27 versus 13 years), while subjects with Campylobacter or Salmonella species belonged to younger age groups (2.6 and 1.6 years, respectively). Salmonella cases were more often in females. Shigella diarrhea was associated with fecal blood or mucus and leukocytes. ETEC was not associated with nausea or vomiting. Anorexia, weight loss, and fever were associated with the isolation of Salmonella and Aeromonas species. EAEC, ETEC, EPEC, and Shigella species were resistant to most drugs used for treating diarrhea in Africa, while the antibiotic most active against all bacteria tested was norfloxacin. We conclude that in Djibouti in 1989, Shigella and Aeromonas species must be considered as potential pathogens whenever they are isolated from diarrheal stools and that norfloxacin should be considered the drug of choice in adults for treating severe shigellosis and for diarrhea prophylaxis in travelers. PMID:2351738
Pizarro-Cerdá, Javier; Charbit, Alain; Enninga, Jost; Lafont, Frank; Cossart, Pascale
Bacterial pathogens display an impressive arsenal of molecular mechanisms that allow survival in diverse host niches. Subversion of plasma membrane and cytoskeletal functions are common themes associated to infection by both extracellular and intracellular pathogens. Moreover, intracellular pathogens modify the structure/stability of their membrane-bound compartments and escape degradation from phagocytic or autophagic pathways. Here, we review the manipulation of host membranes by Listeria monocytogenes, Francisella tularensis, Shigella flexneri and Yersinia spp. These four bacterial model pathogens exemplify generalized strategies as well as specific features observed during bacterial infection processes. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.
Hellberg, Rosalee S; Chu, Eric
According to the Intergovernmental Panel on Climate Change (IPCC), warming of the climate system is unequivocal. Over the coming century, warming trends such as increased duration and frequency of heat waves and hot extremes are expected in some areas, as well as increased intensity of some storm systems. Climate-induced trends will impact the persistence and dispersal of foodborne pathogens in myriad ways, especially for environmentally ubiquitous and/or zoonotic microorganisms. Animal hosts of foodborne pathogens are also expected to be impacted by climate change through the introduction of increased physiological stress and, in some cases, altered geographic ranges and seasonality. This review article examines the effects of climatic factors, such as temperature, rainfall, drought and wind, on the environmental dispersal and persistence of bacterial foodborne pathogens, namely, Bacillus cereus, Brucella, Campylobacter, Clostridium, Escherichia coli, Listeria monocytogenes, Salmonella, Staphylococcus aureus, Vibrio and Yersinia enterocolitica. These relationships are then used to predict how future climatic changes will impact the activity of these microorganisms in the outdoor environment and associated food safety issues. The development of predictive models that quantify these complex relationships will also be discussed, as well as the potential impacts of climate change on transmission of foodborne disease from animal hosts.
Shahid, Naila; Daniell, Henry
The shared diseases between animals and humans are known as zoonotic diseases and spread infectious diseases among humans. Zoonotic diseases are not only a major burden to livestock industry but also threaten humans accounting for >60% cases of human illness. About 75% of emerging infectious diseases in humans have been reported to originate from zoonotic pathogens. Because antibiotics are frequently used to protect livestock from bacterial diseases, the development of antibiotic-resistant strains of epidemic and zoonotic pathogens is now a major concern. Live attenuated and killed vaccines are the only option to control these infectious diseases and this approach has been used since 1890. However, major problems with this approach include high cost and injectable vaccines is impractical for >20 billion poultry animals or fish in aquaculture. Plants offer an attractive and affordable platform for vaccines against animal diseases because of their low cost, and they are free of attenuated pathogens and cold chain requirement. Therefore, several plant-based vaccines against human and animals diseases have been developed recently that undergo clinical and regulatory approval. Plant-based vaccines serve as ideal booster vaccines that could eliminate multiple boosters of attenuated bacteria or viruses, but requirement of injectable priming with adjuvant is a current limitation. So, new approaches like oral vaccines are needed to overcome this challenge. In this review, we discuss the progress made in plant-based vaccines against zoonotic or other animal diseases and future challenges in advancing this field. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.
Kaushik, Rajni; Balasubramanian, Rajasekhar
Bacterial pathogens in airborne particulate matter (PM) and in rainwater (RW) were detected using a robust and sensitive Real-Time PCR method. Both RW and PM were collected simultaneously in the tropical atmosphere of Singapore, which were then subjected to analysis for the presence of selected bacterial pathogens and potential pathogen of health concern ( Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Aeromonas hydrophila). These pathogens were found to be prevalent in both PM and RW samples with E. coli being the most prevalent potential pathogen in both types of samples. The temporal distribution of these pathogens in PM and RW was found to be similar to each other. Using the proposed microbiological technique, the atmospheric deposition (dry and wet deposition) of bacterial pathogens to lakes and reservoirs can be studied in view of growing concerns about the outbreak of waterborne diseases.
Skanata, Antun; Kussell, Edo
Environmental changes can have profound effects on ecosystems, leading to drastic outcomes such as extinction and desertification. Quantifying, predicting, and ultimately preventing those transitions is a key problem in the field. Our previous work in microbial systems has shown that fluctuations in environments drive transitions to alternate evolutionary optima, which can be either smooth or abrupt. The long term growth rate, an analog of free energy for population dynamics, has been used to distinguish under what conditions those transitions will occur. Our framework, which uses the mean field approximation to compute the long term growth rate in fluctuating environments, is uniquely positioned to treat more complex dependencies that allow coexistence among species sharing resources or infected by common pathogens. Here we present a simple model of a bacterial community subjected to fluctuating phage infections that outlines the regimes where species diversity results in long-term stability. We identify prevalent, but often counter-intuitive, strategies that bacteria use to protect against infection, and find a new general principle in the evolution of phage resistance. Our results, which predict the transition regimes, have implications for a broad range of ecological models.
Griffin, Dale W.; Shaefer, F.L.; Charlena Bowling,; Dino Mattorano,; Tonya Nichols,; Erin Silvestri,
This Sample Collection Procedure (SCP) describes the activities and considerations for the collection of bacterial pathogens from representative surface soil samples (0-5 cm). This sampling depth can be reached without the use of a drill rig, direct-push technology, or other mechanized equipment. This procedure can be used in most soil types but is limited to sampling at or near the ground surface. This protocol has components for two different types of sampling applications: (1) typical sampling, when there is no suspicion of contamination (e.g., surveillance or background studies); and (2) in response to known or suspected accidental contamination (e.g., the presence of animal carcasses). This protocol does not cover sampling in response to a suspected bioterrorist or intentional release event. Surface material is removed to the required depth (0-5 cm) and clean trowel or 50 ml sample tube is used to collect the sample. Sample containers are sealed, bagged, and shipped to the laboratory for analysis. Associated documentation, including a Field Data Log and Chain-of-Custody are also included in this document.
Briand, François-Xavier; Schmitz, Audrey; Ogor, Katell; Le Prioux, Aurélie; Guillou-Cloarec, Cécile; Guillemoto, Carole; Allée, Chantal; Le Bras, Marie-Odile; Hirchaud, Edouard; Quenault, Hélène; Touzain, Fabrice; Cherbonnel-Pansart, Martine; Lemaitre, Evelyne; Courtillon, Céline; Gares, Hélène; Daniel, Patrick; Fediaevsky, Alexandre; Massin, Pascale; Blanchard, Yannick; Eterradossi, Nicolas; van der Werf, Sylvie; Jestin, Véronique; Niqueux, Eric
Several new highly pathogenic (HP) H5 avian influenza virus (AIV) have been detected in poultry farms from south-western France since November 2015, among which an HP H5N1. The zoonotic potential and origin of these AIVs immediately became matters of concern. One virus of each subtype H5N1 (150169a), H5N2 (150233) and H5N9 (150236) was characterised. All proved highly pathogenic for poultry as demonstrated molecularly by the presence of a polybasic cleavage site in their HA protein – with a sequence (HQRRKR/GLF) previously unknown among avian H5 HPAI viruses – or experimentally by the in vivo demonstration of an intravenous pathogenicity index of 2.9 for the H5N1 HP isolate. Phylogenetic analyses based on the full genomes obtained by NGS confirmed that the eight viral segments of the three isolates were all part of avian Eurasian phylogenetic lineage but differed from the Gs/Gd/1/96-like lineage. The study of the genetic characteristics at specific amino acid positions relevant for modulating the adaptation to and the virulence for mammals showed that presently, these viruses possess most molecular features characteristic of AIV and lack some major characteristics required for efficient respiratory transmission to or between humans. The three isolates are therefore predicted to have no significant pandemic potential. PMID:28277218
Briand, François-Xavier; Schmitz, Audrey; Ogor, Katell; Le Prioux, Aurélie; Guillou-Cloarec, Cécile; Guillemoto, Carole; Allée, Chantal; Le Bras, Marie-Odile; Hirchaud, Edouard; Quenault, Hélène; Touzain, Fabrice; Cherbonnel-Pansart, Martine; Lemaitre, Evelyne; Courtillon, Céline; Gares, Hélène; Daniel, Patrick; Fediaevsky, Alexandre; Massin, Pascale; Blanchard, Yannick; Eterradossi, Nicolas; van der Werf, Sylvie; Jestin, Véronique; Niqueux, Eric
Several new highly pathogenic (HP) H5 avian influenza virus (AIV) have been detected in poultry farms from south-western France since November 2015, among which an HP H5N1. The zoonotic potential and origin of these AIVs immediately became matters of concern. One virus of each subtype H5N1 (150169a), H5N2 (150233) and H5N9 (150236) was characterised. All proved highly pathogenic for poultry as demonstrated molecularly by the presence of a polybasic cleavage site in their HA protein - with a sequence (HQRRKR/GLF) previously unknown among avian H5 HPAI viruses - or experimentally by the in vivo demonstration of an intravenous pathogenicity index of 2.9 for the H5N1 HP isolate. Phylogenetic analyses based on the full genomes obtained by NGS confirmed that the eight viral segments of the three isolates were all part of avian Eurasian phylogenetic lineage but differed from the Gs/Gd/1/96-like lineage. The study of the genetic characteristics at specific amino acid positions relevant for modulating the adaptation to and the virulence for mammals showed that presently, these viruses possess most molecular features characteristic of AIV and lack some major characteristics required for efficient respiratory transmission to or between humans. The three isolates are therefore predicted to have no significant pandemic potential. This article is copyright of The Authors, 2017.
Qadri, S. M.; Lee, G. C.; Ueno, Y.; Burdette, J. M.
Although most respiratory tract infections are caused by viruses, bacterial pathogens are responsible for higher morbidity and mortality. Because virtually nothing is known about the etiology of bacterial respiratory pathogens in Saudi Arabia, this study examined the incidence of these organisms in 5426 patients over a 1-year period. Of the bacterial pathogens isolated from 904 patients, the most common organism was Hemophilus influenzae (31%), followed by pneumococci (22%), Pseudomonas aeruginosa (16%), and others (31%). Because the first two organisms accounted for more than 50% of isolates, their susceptibility to commonly used antibiotics was also reviewed. The results are presented here. PMID:8496993
Edwards, Andrew M; Massey, Ruth C
Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be applied to the study of cell invasion by virtually any culturable bacterium. The stages at which specific aspects of invasion can be studied, such as the role of actin rearrangement or caveolae, will be highlighted. Host cells are grown in flasks and when ready for use are seeded into 24-well plates containing Thermanox coverslips. Using coverslips allows subsequent removal of the cells from the wells to reduce interference from serum proteins deposited onto the sides of the wells (to which S. aureus would attach). Bacteria are grown to the required density and washed to remove any secreted proteins (e.g. toxins). Coverslips with confluent layers of endothelial cells are transferred to new 24-well plates containing fresh culture medium before the addition of bacteria. Bacteria and cells are then incubated together for the required amount of time in 5% CO(2) at 37°C. For S. aureus this is typically between 15-90 minutes. Thermanox coverslips are removed from each well and dip-washed in PBS to remove unattached bacteria. If total associated bacteria (adherent and internalised) are to be quantified, coverslips are then placed in a fresh well containing 0.5% Triton X-100 in PBS. Gentle pipetting leads to complete cell lysis and bacteria are enumerated by serial dilution and plating onto agar. If the number of bacteria that have invaded the cells is needed, coverslips are added to wells containing 500 μl tissue culture medium supplemented with gentamicin and incubation continued for 1 h, which will kill all external bacteria. Coverslips can then be washed, cells lysed and bacteria enumerated by plating onto agar as described above. If the experiment requires direct visualisation, coverslips can be fixed and stained for light, fluorescence or confocal microscopy or prepared for electron microscopy.
Ticks are of medical and veterinary importance due to their ability to transmit pathogens to humans and animals. The Rocky Mountain wood tick, Dermacentor andersoni, is a vector of a number of pathogens, including Anaplasma marginale, which is the most widespread tick-borne pathogen of livestock. Al...
Keane, O M; Budd, K E; Flynn, J; McCoy, F
Rapid and accurate identification of mastitis pathogens is important for disease control. Bacterial culture and isolate identification is considered the gold standard in mastitis diagnosis but is time consuming and results in many culture-negative samples. Identification of mastitis pathogens by PCR has been proposed as a fast and sensitive alternative to bacterial culture. The results of bacterial culture and PCR for the identification of the aetiological agent of clinical mastitis were compared. The pathogen identified by traditional culture methods was also detected by PCR in 98 per cent of cases indicating good agreement between the positive results of bacterial culture and PCR. A mastitis pathogen could not be recovered from approximately 30 per cent of samples by bacterial culture, however, an aetiological agent was identified by PCR in 79 per cent of these samples. Therefore, a mastitis pathogen was detected in significantly more milk samples by PCR than by bacterial culture (92 per cent and 70 per cent, respectively) although the clinical relevance of PCR-positive culture-negative results remains controversial. A mixed infection of two or more mastitis pathogens was also detected more commonly by PCR. Culture-negative samples due to undetected Staphylococcus aureus infections were rare. The use of PCR technology may assist in rapid mastitis diagnosis, however, accurate interpretation of PCR results in the absence of bacterial culture remains problematic.
Foodborne pathogens remain global health problems despite concerted efforts to control the transmission of these microorganisms through food. The resurgence of drug resistant bacteria has renewed interest in developing and testing new sources of antimicrobial agents to control foodborne illness. Thi...
Delabouglise, A; Antoine-Moussiaux, N; Tatong, D; Chumkaeo, A; Binot, A; Fournié, G; Pilot, E; Phimpraphi, W; Kasemsuwan, S; Paul, M C; Duboz, R; Salem, G; Peyre, M
Effectiveness of current passive zoonotic disease surveillance systems is limited by the under-reporting of disease outbreaks in the domestic animal population. Evaluating the acceptability of passive surveillance and its economic, social and cultural determinants appears a critical step for improving it. A participatory rural appraisal was implemented in a rural subdistrict of Thailand. Focus group interviews were used to identify sanitary risks perceived by native chicken farmers and describe the structure of their value chain. Qualitative individual interviews with a large diversity of actors enabled to identify perceived costs and benefits associated with the reporting of HPAI suspicions to sanitary authorities. Besides, flows of information on HPAI suspected cases were assessed using network analysis, based on data collected through individual questionnaires. Results show that the presence of cockfighting activities in the area negatively affected the willingness of all chicken farmers and other actors to report suspected HPAI cases. The high financial and affective value of fighting cocks contradicted the HPAI control policy based on mass culling. However, the importance of product quality in the native chicken meat value chain and the free veterinary services and products delivered by veterinary officers had a positive impact on suspected case reporting. Besides, cockfighting practitioners had a significantly higher centrality than other actors in the information network and they facilitated the spatial diffusion of information. Social ties built in cockfighting activities and the shared purpose of protecting valuable cocks were at the basis of the diffusion of information and the informal collective management of diseases. Building bridges with this informal network would greatly improve the effectiveness of passive surveillance. © 2016 Blackwell Verlag GmbH.
Steele-Mortimer, O; Knodler, L A; Finlay, B B
The cytoskeleton of eukaryotic cells is affected by a number of bacterial and viral pathogens. In this review we consider three recurring themes of cytoskeletal involvement in bacterial pathogenesis: 1) the effect of bacterial toxins on actin-regulating small GTP-binding proteins; 2) the invasion of non-phagocytic cells by the bacterial induction of ruffles at the plasma membrane; 3) the formation of actin tails and pedestals by intracellular and extracellular bacteria, respectively. Considerable progress has been made recently in the characterization of these processes. It is becoming clear that bacterial pathogens have developed a variety of sophisticated mechanisms for utilizing the complex cytoskeletal system of host cells. These bacterially-induced processes are now providing unique insights into the regulation of fundamental eukaryotic mechanisms.
J.D. Podgwaite; R.W. Campbell
Eighty-six pathogenic aerobic bacterial isolates from diseased gypsy moth larvae collected in both sparse and dense populations were characterized and identified as members of the families Bacillaceae, Enterobacteriaceae, Lactobacillaceae, Pseudomonadaceae, and Achromobacteraceae. The commonest pathogens were Streptococcus faecalis, Bacillus cereus, Bacillus...
Zagólski, Olaf; Stręk, Paweł; Kasprowicz, Andrzej; Białecka, Anna
Background Polyvalent bacterial lysate (PBL) is an oral immunostimulating vaccine consisting of bacterial standardized lysates obtained by lysis of different strains of bacteria. Autovaccines are individually prepared based on the results of smears obtained from the patient. Both types of vaccine can be used to treat an ongoing chronic infection. This study sought to determine which method is more effective against nasal colonization by potential respiratory tract pathogens. Material/Methods We enrolled 150 patients with aerobic Gram stain culture and count results indicating bacterial colonization of the nose and/or throat by potential pathogens. The participants were randomly assigned to each of the following groups: 1. administration of PBL, 2. administration of autovaccine, and 3. no intervention (controls). Results Reduction of the bacterial count in Streptococcus pneumoniae-colonized participants was significant after the autovaccine (p<0.001) and PBL (p<0.01). Reduction of the bacterial count of other β-hemolytic streptococcal strains after treatment with the autovaccine was significant (p<0.01) and was non-significant after PBL. In Haemophilus influenzae colonization, significant reduction in the bacterial count was noted in the PBL group (p<0.01). Methicillin-resistant Staphylococcus aureus colonization did not respond to either treatment. Conclusions The autovaccine is more effective than PBL for reducing bacterial count of Streptococcus pneumoniae and β-hemolytic streptococci, while PBL was more effective against Haemophilus influenzae colonization. PMID:26434686
Iraola, Gregorio; Vazquez, Gustavo; Spangenberg, Lucía; Naya, Hugo
Although there have been great advances in understanding bacterial pathogenesis, there is still a lack of integrative information about what makes a bacterium a human pathogen. The advent of high-throughput sequencing technologies has dramatically increased the amount of completed bacterial genomes, for both known human pathogenic and non-pathogenic strains; this information is now available to investigate genetic features that determine pathogenic phenotypes in bacteria. In this work we determined presence/absence patterns of different virulence-related genes among more than finished bacterial genomes from both human pathogenic and non-pathogenic strains, belonging to different taxonomic groups (i.e: Actinobacteria, Gammaproteobacteria, Firmicutes, etc.). An accuracy of 95% using a cross-fold validation scheme with in-fold feature selection is obtained when classifying human pathogens and non-pathogens. A reduced subset of highly informative genes () is presented and applied to an external validation set. The statistical model was implemented in the BacFier v1.0 software (freely available at ), that displays not only the prediction (pathogen/non-pathogen) and an associated probability for pathogenicity, but also the presence/absence vector for the analyzed genes, so it is possible to decipher the subset of virulence genes responsible for the classification on the analyzed genome. Furthermore, we discuss the biological relevance for bacterial pathogenesis of the core set of genes, corresponding to eight functional categories, all with evident and documented association with the phenotypes of interest. Also, we analyze which functional categories of virulence genes were more distinctive for pathogenicity in each taxonomic group, which seems to be a completely new kind of information and could lead to important evolutionary conclusions. PMID:22916122
Brettar, Ingrid; Höfle, Manfred G
Human bacterial pathogens are considered as an increasing threat to drinking water supplies worldwide because of the growing demand of high-quality drinking water and the decreasing quality and quantity of available raw water. Moreover, a negative impact of climate change on freshwater resources is expected. Recent advances in molecular detection technologies for bacterial pathogens in drinking water bear the promise in improving the safety of drinking water supplies by precise detection and identification of the pathogens. More importantly, the array of molecular approaches allows understanding details of infection routes of waterborne diseases, the effects of changes in drinking water treatment, and management of freshwater resources.
Wronowska, Weronika; Godlewska, Renata; Jagusztyn-Krynicka, Elzbieta Katarzyna
Several pathogenic bacteria are able to trigger apoptosis in the host cell, but the mechanisms by which it occurs differ, and the resulting pathology can take different courses. Induction and/or blockage of programmed cell death upon infection is a result of complex interaction of bacterial proteins with cellular proteins involved in signal transduction and apoptosis. In this review we focus on pro/anti-apoptotic activities exhibited by two enteric pathogens Salmonella enterica, Yersinia spp. and gastric pathogen Helicobacter pylori. We present current knowledge on how interaction between mammalian and bacterial cell relates to the molecular pathways of apoptosis, and what is the role of apoptosis in pathogenesis.
This work presents the development of a method for rapid bacterial identification based on the fluorescence spectroscopy combined with multivariate analysis. Fluorescence spectra of pure three different genera of bacteria (Escherichia coli, Salmonella, and Campylobacter) were collected from 200...
Hajishengallis, George; Lamont, Richard J
Many diseases that originate on mucosal membranes ensue from the action of polymicrobial communities of indigenous organisms working in concert to disrupt homeostatic mechanisms. Multilevel physical and chemical communication systems among constituent organisms underlie polymicrobial synergy and dictate the community's pathogenic potential or nososymbiocity, that is, disease arising from living together with a susceptible host. Functional specialization of community participants, often originating from metabolic codependence, has given rise to several newly appreciated designations within the commensal-to-pathogen spectrum. Accessory pathogens, while inherently commensal in a particular microenvironment, nonetheless enhance the colonization or metabolic activity of pathogens. Keystone pathogens (bacterial drivers or alpha-bugs) exert their influence at low abundance by modulating both the composition and levels of community participants and by manipulating host responses. Pathobionts (or bacterial passengers) exploit disrupted host homeostasis to flourish and promote inflammatory disease. In this review we discuss how commensal or pathogenic properties of organisms are not intrinsic features, and have to be considered within the context of both the microbial community in which they reside and the host immune status. Copyright © 2016 Elsevier Ltd. All rights reserved.
Das, Anusmita; Patgiri, Saurav J; Saikia, Lahari; Dowerah, Pritikar; Nath, Reema
To determine the spectrum of bacterial pathogens causing community-acquired pneumonia in children below 5 years of age. Children aged below 5 years satisfying the WHO criteria for pneumonia, severe pneumonia or very severe pneumonia, and with the presence of lung infiltrates on chest X-ray were enrolled. Two respiratory samples, one for culture and the other for PCR analysis, and a blood sample for culture were collected from every child. Of the 180 samples processed, bacterial pathogens were detected in 64.4%. Streptococcus pneumoniae and Hemophilus influenzae were most frequently detected. The performance of PCR analysis and culture were identical for the typical bacterial pathogens; atypical pathogens were detected by PCR analysis only. S. pneumoniae and H. influenza were the most commonly detected organisms from respiratory secretions of children with community acquired pneumonia.
Chen, Quan; Zhu, Zhiling; Wang, Jun; Lopez, Analette I; Li, Siheng; Kumar, Amit; Yu, Fei; Chen, Haoqing; Cai, Chengzhi; Zhang, Lijuan
Bacterial interference is an alternative strategy to fight against device-associated bacterial infections. Pursuing this strategy, a non-pathogenic bacterial biofilm is used as a live, protective barrier to fence off pathogen colonization. In this work, biofilms formed by probiotic Escherichia coli strain Nissle 1917 (EcN) are investigated for their potential for long-term bacterial interference against infections associated with silicone-based urinary catheters and indwelling catheters used in the digestive system, such as feeding tubes and voice prostheses. We have shown that EcN can form stable biofilms on silicone substrates, particularly those modified with a biphenyl mannoside derivative. These biofilms greatly reduced the colonization by pathogenic Enterococcus faecalis in Lysogeny broth (LB) for 11days. Bacterial interference is an alternative strategy to fight against device-associated bacterial infections. Pursuing this strategy, we use non-pathogenic bacteria to form a biofilm that serves as a live, protective barrier against pathogen colonization. Herein, we report the first use of preformed probiotic E. coli Nissle 1917 biofilms on the mannoside-presenting silicone substrates to prevent pathogen colonization. The biofilms serve as a live, protective barrier to fence off the pathogens, whereas current antimicrobial/antifouling coatings are subjected to gradual coverage by the biomass from the rapidly growing pathogens in a high-nutrient environment. It should be noted that E. coli Nissle 1917 is commercially available and has been used in many clinical trials. We also demonstrated that this probiotic strain performed significantly better than the non-commercial, genetically modified E. coli strain that we previously reported. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Li, Bing; Ju, Feng; Cai, Lin; Zhang, Tong
The broad-spectrum profile of bacterial pathogens and their fate in sewage treatment plants (STPs) were investigated using high-throughput sequencing based metagenomic approach. This novel approach could provide a united platform to standardize bacterial pathogen detection and realize direct comparison among different samples. Totally, 113 bacterial pathogen species were detected in eight samples including influent, effluent, activated sludge (AS), biofilm, and anaerobic digestion sludge with the abundances ranging from 0.000095% to 4.89%. Among these 113 bacterial pathogens, 79 species were reported in STPs for the first time. Specially, compared to AS in bulk mixed liquor, more pathogen species and higher total abundance were detected in upper foaming layer of AS. This suggests that the foaming layer of AS might impose more threat to onsite workers and citizens in the surrounding areas of STPs because pathogens in foaming layer are easily transferred into air and cause possible infections. The high removal efficiency (98.0%) of total bacterial pathogens suggests that AS treatment process is effective to remove most bacterial pathogens. Remarkable similarities of bacterial pathogen compositions between influent and human gut indicated that bacterial pathogen profiles in influents could well reflect the average bacterial pathogen communities of urban resident guts within the STP catchment area.
Cox, Christopher R.; Voorhees, Kent J.
Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.
Banskar, Sunil; Bhute, Shrikant S.; Suryavanshi, Mangesh V.; Punekar, Sachin; Shouche, Yogesh S.
Bats are crucial for proper functioning of an ecosystem. They provide various important services to ecosystem and environment. While, bats are well-known carrier of pathogenic viruses, their possible role as a potential carrier of pathogenic bacteria is under-explored. Here, using culture-based approach, employing multiple bacteriological media, over thousand bacteria were cultivated and identified from Rousettus leschenaultii (a frugivorous bat species), the majority of which were from the family Enterobacteriaceae and putative pathogens. Next, pathogenic potential of most frequently cultivated component of microbiome i.e. Escherichia coli was assessed to identify its known pathotypes which revealed the presence of virulent factors in many cultivated E. coli isolates. Applying in-depth bacterial community analysis using high-throughput 16 S rRNA gene sequencing, a high inter-individual variation was observed among the studied guano samples. Interestingly, a higher diversity of bacterial communities was observed in decaying guano representative. The search against human pathogenic bacteria database at 97% identity, a small proportion of sequences were found associated to well-known human pathogens. The present study thus indicates that this bat species may carry potential bacterial pathogens and advice to study the effect of these pathogens on bats itself and the probable mode of transmission to humans and other animals. PMID:27845426
Banskar, Sunil; Bhute, Shrikant S; Suryavanshi, Mangesh V; Punekar, Sachin; Shouche, Yogesh S
Bats are crucial for proper functioning of an ecosystem. They provide various important services to ecosystem and environment. While, bats are well-known carrier of pathogenic viruses, their possible role as a potential carrier of pathogenic bacteria is under-explored. Here, using culture-based approach, employing multiple bacteriological media, over thousand bacteria were cultivated and identified from Rousettus leschenaultii (a frugivorous bat species), the majority of which were from the family Enterobacteriaceae and putative pathogens. Next, pathogenic potential of most frequently cultivated component of microbiome i.e. Escherichia coli was assessed to identify its known pathotypes which revealed the presence of virulent factors in many cultivated E. coli isolates. Applying in-depth bacterial community analysis using high-throughput 16 S rRNA gene sequencing, a high inter-individual variation was observed among the studied guano samples. Interestingly, a higher diversity of bacterial communities was observed in decaying guano representative. The search against human pathogenic bacteria database at 97% identity, a small proportion of sequences were found associated to well-known human pathogens. The present study thus indicates that this bat species may carry potential bacterial pathogens and advice to study the effect of these pathogens on bats itself and the probable mode of transmission to humans and other animals.
Kusiluka, L. J. M.; Karimuribo, E. D.; Mdegela, R. H.; Luoga, E. J.; Munishi, P. K. T.; Mlozi, M. R. S.; Kambarage, D. M.
A study on the prevalence of water-borne zoonotic pathogens in water, cattle and humans was conducted in six villages in Dodoma Rural (5) and Bagamoyo (1) districts, Tanzania. Water sources were screened for faecal coliform organisms, thermophilic Campylobacter, Salmonella, Cryptosporidium and Giardia. Faecal samples from cattle and humans were also analysed for the above specific pathogens. Results indicate that 70.8% ( n = 48) of the water sources screened were contaminated with faecal coliform organisms. Water sources in two villages, one each in Dodoma Rural and Bagamoyo districts were also contaminated with Giardia lamblia. The overall prevalence of Campylobacter jejuni in cattle in the two study areas was 2.3% ( n = 942) and at least one animal in each village was infected with C. jejuni. Cryptosporidium parvum was detected in 0.5% ( n = 942) of the cattle examined in three villages in Dodoma district. Salmonella spp. was demonstrated in only 1.4% ( n = 144) of the cattle in Chalinze village in Dodoma Rural district while G. lamblia was only detected in 1.5% ( n = 202) of the animals examined in Chamakweza village in Bagamoyo district. Nine (1.9%) of the people screened at three heath centres in the study areas were infected with C. jejuni while 3.7% ( n = 484) of the people had C. parvum oocysts. G. lamblia was detected in 2.5% of the 202 people screened at the Chalinze health centre in Bagamoyo district. Analysis of the secondary data revealed that clinical complaints related to enteric diseases were prevalent in humans in the two areas throughout the year and the prevalence varied from about 1% to 25% in both <5 years and ⩾5 years patients. In conclusion, this study has highlighted the possible public health risks, which may be associated with keeping of animals and sharing of water sources between humans and animals.
Coulaud, Pierre-Julien; Lepolard, Catherine; Bechah, Yassina; Berenger, Jean-Michel; Raoult, Didier; Ghigo, Eric
Pediculus humanus humanus is an human ectoparasite which represents a serious public health threat because it is vector for pathogenic bacteria. It is important to understand and identify where bacteria reside in human body lice to define new strategies to counterstroke the capacity of vectorization of the bacterial pathogens by body lice. It is known that phagocytes from vertebrates can be hosts or reservoirs for several microbes. Therefore, we wondered if Pediculus humanus humanus phagocytes could hide pathogens. In this study, we characterized the phagocytes from Pediculus humanus humanus and evaluated their contribution as hosts for human pathogens such as Rickettsia prowazekii, Bartonella Quintana, and Acinetobacter baumannii. PMID:25688336
Several bacterial pathogens, including Listeria monocytogenes, Shigella flexneri and Rickettsia spp., have evolved mechanisms to actively spread within human tissues. Spreading is initiated by the pathogen-induced recruitment of host filamentous (F)-actin. F-actin forms a tail behind the microbe, propelling it through the cytoplasm. The motile pathogen then encounters the host plasma membrane, forming a bacterium-containing protrusion that is engulfed by an adjacent cell. Over the past two decades, much progress has been made in elucidating mechanisms of F-actin tail formation. Listeria and Shigella produce tails of branched actin filaments by subverting the host Arp2/3 complex. By contrast, Rickettsia forms tails with linear actin filaments through a bacterial mimic of eukaryotic formins. Compared with F-actin tail formation, mechanisms controlling bacterial protrusions are less well understood. However, recent findings have highlighted the importance of pathogen manipulation of host cell-cell junctions in spread. Listeria produces a soluble protein that enhances bacterial protrusions by perturbing tight junctions. Shigella protrusions are engulfed through a clathrin-mediated pathway at 'tricellular junctions'--specialized membrane regions at the intersection of three epithelial cells. This review summarizes key past findings in pathogen spread, and focuses on recent developments in actin-based motility and the formation and internalization of bacterial protrusions.
Villette, P; Afonso, E; Couval, G; Levret, A; Galan, M; Tatard, C; Cosson, J F; Giraudoux, P
High-throughput sequencing technologies now allow for rapid cost-effective surveys of multiple pathogens in many host species including rodents, but it is currently unclear if the organ chosen for screening influences the number and identity of bacteria detected. We used 16S rRNA amplicon sequencing to identify bacterial pathogens in the heart, liver, lungs, kidneys and spleen of 13 water voles (Arvicola terrestris) collected in Franche-Comté, France. We asked if bacterial pathogen assemblages within organs are similar and if all five organs are necessary to detect all of the bacteria present in an individual animal. We identified 24 bacteria representing 17 genera; average bacterial richness for each organ ranged from 1·5 ± 0·4 (mean ± standard error) to 2·5 ± 0·4 bacteria/organ and did not differ significantly between organs. The average bacterial richness when organ assemblages were pooled within animals was 4·7 ± 0·6 bacteria/animal; Operational Taxonomic Unit accumulation analysis indicates that all five organs are required to obtain this. Organ type influences bacterial assemblage composition in a systematic way (PERMANOVA, 999 permutations, pseudo-F 4,51 = 1·37, P = 0·001). Our results demonstrate that the number of organs sampled influences the ability to detect bacterial pathogens, which can inform sampling decisions in public health and wildlife ecology.
Wells, J E; Berry, E D; Guerini, M N; Varel, V H
To evaluate natural terpene compounds for antimicrobial activities and determine whether these compounds could be used to control microbial activities and pathogens in production animal facilities. Thymol, geraniol, glydox, linalool, pine oil, plinol and terpineol were tested in laboratory studies for ability to control the production of odorous volatile fatty acid compounds and reduce pathogen levels in manure slurry preparations. Thymol is a terpene phenolic compound and was most effective for reducing fermentation products and pathogen levels (P < 0.05), followed by the extracts linalool, pine oil and terpineol, which are terpene alcohols. Select compounds thymol, linalool and pine oil were further evaluated in two separate studies by applying the agents to feedlot surfaces in cattle pens. Feedlot surface material (FSM; manure and soil) was collected and analysed for fermentation products, levels of coliforms and total Escherichia coli, and the presence of E. coli O157:H7, Campylobacter, Salmonella, Listeria and L. monocytogenes. The reduction in fermentation products but not pathogens was dependent on the moisture present in the FSM. Treatment with 2000 ppm thymol reduced the prevalence of E. coli O157:H7 but not Listeria. In a separate study, treatment with 4000 ppm pine oil reduced E. coli O157:H7, Listeria and Campylobacter (P < 0.05). Linalool was tested at two levels (2000 and 4000 ppm) and did not affect pathogen levels at either concentration. Natural compounds bearing terpenes can control pathogenic bacteria in treated manures and when applied to the feedlot surface in production cattle systems. Pine oil is a cheaper alternative to thymol and may be a useful treatment for controlling pathogens. The control of bacterial pathogens in animal productions systems is an important step in preharvest food safety. Waste products, such as pine oil extract, from the pulp wood industry may have application for treating feedlot pens and manures to reduce the
Yan, Muxia; Li, Weidong; Zhou, Zhenwen; Peng, Hongxia; Luo, Ziyan; Xu, Ling
In this work, loop-mediated isothermal amplification based detection assay using bacterial culture and bacterial colony for various common pathogens direct detection had been established, evaluated and further applied. A total of five species of common pathogens and nine detection targets (tlh, tdh and trh for V. Parahaemolyticus, rfbE, stx1 and stx2 for E. coli, oprI for P. aeruginosa, invA for Salmonella and hylA for L. monocytogenes) were performed on bacterial culture and bacterial colony LAMP. To evaluate and optimize this assay, a total of 116 standard strains were included. Then, for each detected targets, 20 random selected strains were applied. Results were determined through both visual observation of the changed color by naked eye and electrophoresis, which increased the accuracy of survey. The minimum adding quantity of each primer had been confirmed, and the optimal amplification was obtained under 65 °C for 45 min with 25 μl reaction volume. The detection limit of bacterial culture LAMP and PCR assay were determined to be 10 2 and 10 4 or 10 5 CFU/reaction, respectively. No false positive amplification was observed when subjecting the bacterial -LAMP assay to 116 reference strains. This was the first report of colony-LAMP and culture-LAMP assay, which had been demonstrated to be a fast, reliable, cost-effective and simple method on detection of various common pathogens. Copyright © 2016 Elsevier Ltd. All rights reserved.
Sharma, Manan; Reynnells, Russell
Biological soil amendments (BSAs) such as manure and compost are frequently used as organic fertilizers to improve the physical and chemical properties of soils. However, BSAs have been known to be a reservoir for enteric bacterial pathogens such as enterohemorrhagic Escherichia coli (EHEC), Salmonella spp., and Listeria spp. There are numerous mechanisms by which manure may transfer pathogens to growing fruits and vegetables, and several outbreaks of infections have been linked to manure-related contamination of leafy greens. In the United States several commodity-specific guidelines and current and proposed federal rules exist to provide guidance on the application of BSAs as fertilizers to soils, some of which require an interval between the application of manure to soils and the harvest of fruits and vegetables. This review examines the survival, persistence, and regrowth/resuscitation of bacterial pathogens in manure, biosolids, and composts. Moisture, along with climate and the physicochemical properties of soil, manure, or compost, plays a significant role in the ability of pathogens to persist and resuscitate in amended soils. Adaptation of enteric bacterial pathogens to the nonhost environment of soils may also extend their persistence in manure- or compost-amended soils. The presence of antibiotic-resistance genes in soils may also be increased by manure application. Overall, BSAs applied as fertilizers to soils can support the survival and regrowth of pathogens. BSAs should be handled and applied in a manner that reduces the prevalence of pathogens in soils and the likelihood of transfer of food-borne pathogens to fruits and vegetables. This review will focus on two BSAs-raw manure and composted manure (and other feedstocks)-and predominantly on the survival of enteric bacterial pathogens in BSAs as applied to soils as organic fertilizers.
Hammarlöf, Disa L; Canals, Rocío; Hinton, Jay C D
The availability of thousands of genome sequences of bacterial pathogens poses a particular challenge because each genome contains hundreds of genes of unknown function (FUN). How can we easily discover which FUN genes encode important virulence factors? One solution is to combine two different functional genomic approaches. First, transcriptomics identifies bacterial FUN genes that show differential expression during the process of mammalian infection. Second, global mutagenesis identifies individual FUN genes that the pathogen requires to cause disease. The intersection of these datasets can reveal a small set of candidate genes most likely to encode novel virulence attributes. We demonstrate this approach with the Salmonella infection model, and propose that a similar strategy could be used for other bacterial pathogens. Copyright © 2013 Elsevier Ltd. All rights reserved.
Brovko, Lubov Y; Anany, Hany; Griffiths, Mansel W
This chapter presents recent advances in bacteriophage research and their application in the area of food safety. Section 1 describes general facts on phage biology that are relevant to their application for control and detection of bacterial pathogens in food and environmental samples. Section 2 summarizes the recently acquired data on application of bacteriophages to control growth of bacterial pathogens and spoilage organisms in food and food-processing environment. Section 3 deals with application of bacteriophages for detection and identification of bacterial pathogens. Advantages of bacteriophage-based methods are presented and their shortcomings are discussed. The chapter is intended for food scientist and food product developers, and people in food inspection and health agencies with the ultimate goal to attract their attention to the new developing technology that has a tremendous potential in providing means for producing wholesome and safe food. Copyright © 2012 Elsevier Inc. All rights reserved.
Hijaz, Faraj; Ebert, Timothy A.; Rogers, Michael E.
ABSTRACT Insect-transmitted plant-pathogenic bacteria may alter their vectors' fitness, survival, behavior, and metabolism. Because these pathogens interact with their vectors on the cellular and organismal levels, potential changes at the biochemical level might occur. “Candidatus Liberibacter asiaticus” (CLas) is transmitted in a persistent, circulative, and propagative manner. The genome of CLas revealed the presence of an ATP translocase that mediates the uptake of ATP and other nucleotides from medium to achieve its biological processes, such as growth and multiplication. Here, we showed that the levels of ATP and many other nucleotides were significantly higher in CLas-infected than healthy psyllids. Gene expression analysis showed upregulation for ATP synthase subunits, while ATPase enzyme activity showed a decrease in ATPase activity. These results indicated that CLas stimulated Diaphorina citri to produce more ATP and many other energetic nucleotides, while it may inhibit their consumption by the insect. As a result of ATP accumulation, the adenylated energy charge (AEC) increased and the AMP/ATP and ADP/ATP ratios decreased in CLas-infected D. citri psyllids. Survival analysis confirmed a shorter life span for CLas-infected D. citri psyllids. In addition, electropenetrography showed a significant reduction in total nonprobing time, salivation time, and time from the last E2 (phloem ingestion) to the end of recording, indicating that CLas-infected psyllids were at a higher hunger level and they tended to forage more often. This increased feeding activity reflects the CLas-induced energetic stress. In conclusion, CLas alters the energy metabolism of its psyllid vector, D. citri, in order to secure its need for energetic nucleotides. IMPORTANCE Insect transmission of plant-pathogenic bacteria involves propagation and circulation of the bacteria within their vectors. The transmission process is complex and requires specific interactions at the molecular
engineering and SB methods such as recombineering, clustered regularly interspaced short palindromic repeats ( CRISPR ), and bacterial cell-cell...Cholera# Yersinia pseudotuberculosis# Staphylococcus aureus* Phage Engineering CRISPR /Cas9 Delivery of CRISPR genes and RNA guides for sequence...bear very close sequence alignment to the harmless strains via the use of the CRISPR /Cas9 system. The CRISPR system specifically targets a DNA sequence
Cosentino, Salvatore; Voldby Larsen, Mette; Møller Aarestrup, Frank; Lund, Ole
Although the majority of bacteria are harmless or even beneficial to their host, others are highly virulent and can cause serious diseases, and even death. Due to the constantly decreasing cost of high-throughput sequencing there are now many completely sequenced genomes available from both human pathogenic and innocuous strains. The data can be used to identify gene families that correlate with pathogenicity and to develop tools to predict the pathogenicity of newly sequenced strains, investigations that previously were mainly done by means of more expensive and time consuming experimental approaches. We describe PathogenFinder (http://cge.cbs.dtu.dk/services/PathogenFinder/), a web-server for the prediction of bacterial pathogenicity by analysing the input proteome, genome, or raw reads provided by the user. The method relies on groups of proteins, created without regard to their annotated function or known involvement in pathogenicity. The method has been built to work with all taxonomic groups of bacteria and using the entire training-set, achieved an accuracy of 88.6% on an independent test-set, by correctly classifying 398 out of 449 completely sequenced bacteria. The approach here proposed is not biased on sets of genes known to be associated with pathogenicity, thus the approach could aid the discovery of novel pathogenicity factors. Furthermore the pathogenicity prediction web-server could be used to isolate the potential pathogenic features of both known and unknown strains.
Clark, Emily L; Emmadi, Madhu; Krupp, Katharine L; Podilapu, Ananda R; Helble, Jennifer D; Kulkarni, Suvarn S; Dube, Danielle H
Bacterial glycans contain rare, exclusively bacterial monosaccharides that are frequently linked to pathogenesis and essentially absent from human cells. Therefore, bacterial glycans are intriguing molecular targets. However, systematic discovery of bacterial glycoproteins is hampered by the presence of rare deoxy amino sugars, which are refractory to traditional glycan-binding reagents. Thus, the development of chemical tools that label bacterial glycans is a crucial step toward discovering and targeting these biomolecules. Here, we explore the extent to which metabolic glycan labeling facilitates the studying and targeting of glycoproteins in a range of pathogenic and symbiotic bacterial strains. We began with an azide-containing analog of the naturally abundant monosaccharide N-acetylglucosamine and discovered that it is not broadly incorporated into bacterial glycans, thus revealing a need for additional azidosugar substrates to broaden the utility of metabolic glycan labeling in bacteria. Therefore, we designed and synthesized analogs of the rare deoxy amino d-sugars N-acetylfucosamine, bacillosamine, and 2,4-diacetamido-2,4,6-trideoxygalactose and established that these analogs are differentially incorporated into glycan-containing structures in a range of pathogenic and symbiotic bacterial species. Further application of these analogs will refine our knowledge of the glycan repertoire in diverse bacteria and may find utility in treating a variety of infectious diseases with selectivity.
Rapicavoli, Jeannette N; Kinsinger, Nichola; Perring, Thomas M; Backus, Elaine A; Shugart, Holly J; Walker, Sharon; Roper, M Caroline
Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
Rapicavoli, Jeannette N.; Kinsinger, Nichola; Perring, Thomas M.; Backus, Elaine A.; Shugart, Holly J.; Walker, Sharon
Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. PMID:26386068
Bacterial pathogens have evolved various strategies to avoid immune surveillance, depending of their in vivo'lifestyle'. The identification of few bacterial effectors capable to enter the nucleus and modifying chromatin structure in host raises the fascinating questions of how pathogens modulate chromatin structure and why. Chromatin is a dynamic structure that maintains the stability and accessibility of the host DNA genome to the transcription machinery. This review describes the various strategies used by pathogens to interface with host chromatin. In some cases, chromatin injury can be a strategy to take control of major cellular functions, such as the cell cycle. In other cases, manipulation of chromatin structure at specific genomic locations by modulating epigenetic information provides a way for the pathogen to impose its own transcriptional signature onto host cells. This emerging field should strongly influence our understanding of chromatin regulation at interphase nucleus and may provide invaluable openings to the control of immune gene expression in inflammatory and infectious diseases.
Bishai, David; Liu, Liang; Shiau, Stephanie; Wang, Harrison; Tsai, Cindy; Liao, Margaret; Prakash, Shivaani; Howard, Tracy
The purpose of this study was to estimate the risk of acquiring pathogenic bacteria as a result of shaking hands at graduation ceremonies. School officials participating in graduation ceremonies at elementary, secondary, and postsecondary schools were recruited. Specimens were collected before and immediately following graduation. Cultures identified any pathogenic bacteria in each specimen. Subjects shook a total of 5,209 hands. Staphylococcus aureus was separately detected on one pregraduation right hand, one postgraduation right hand, and one postgraduation left hand. Nonpathogenic bacteria were collected in 93% of specimens. Pregraduation and postgraduation specimens were of different strains. We measured a risk of one new bacterial acquisition in a sample exposed to 5,209 handshakes yielding an overall estimate of 0.019 pathogens acquired per handshake. We conclude that a single handshake at a graduation offers only a small risk of bacterial pathogen acquisition.
Brüssow, Harald; Canchaya, Carlos; Hardt, Wolf-Dietrich
Comparative genomics demonstrated that the chromosomes from bacteria and their viruses (bacteriophages) are coevolving. This process is most evident for bacterial pathogens where the majority contain prophages or phage remnants integrated into the bacterial DNA. Many prophages from bacterial pathogens encode virulence factors. Two situations can be distinguished: Vibrio cholerae, Shiga toxin-producing Escherichia coli, Corynebacterium diphtheriae, and Clostridium botulinum depend on a specific prophage-encoded toxin for causing a specific disease, whereas Staphylococcus aureus, Streptococcus pyogenes, and Salmonella enterica serovar Typhimurium harbor a multitude of prophages and each phage-encoded virulence or fitness factor makes an incremental contribution to the fitness of the lysogen. These prophages behave like “swarms” of related prophages. Prophage diversification seems to be fueled by the frequent transfer of phage material by recombination with superinfecting phages, resident prophages, or occasional acquisition of other mobile DNA elements or bacterial chromosomal genes. Prophages also contribute to the diversification of the bacterial genome architecture. In many cases, they actually represent a large fraction of the strain-specific DNA sequences. In addition, they can serve as anchoring points for genome inversions. The current review presents the available genomics and biological data on prophages from bacterial pathogens in an evolutionary framework. PMID:15353570
Luo, Gang; Angelidaki, Irini
The present study investigated the changes of bacterial community composition including bacterial pathogens along a biogas plant, i.e. from the influent, to the biogas reactor and to the post-digester. The effects of post-digestion temperature and time on the changes of bacterial community composition and bacterial pathogens were also studied. Microbial analysis was made by Ion Torrent sequencing of the PCR amplicons from ethidium monoazide treated samples, and ethidium monoazide was used to cleave DNA from dead cells and exclude it from PCR amplification. Both similarity and taxonomic analysis showed that the bacterial community composition in the influent was changed after anaerobic digestion. Firmicutes were dominant in all the samples, while Proteobacteria decreased in the biogas reactor compared with the influent. Variations of bacterial community composition in the biogas reactor with time were also observed. This could be attributed to varying composition of the influent. Batch experiments showed that the methane recovery from the digested residues (obtained from biogas reactor) was mainly related with post-digestion temperature. However, post-digestion time rather than temperature had a significant effect on the changes of bacterial community composition. The changes of bacterial community composition were also reflected in the changes of relative abundance of bacterial pathogens. The richness and relative abundance of bacterial pathogens were reduced after anaerobic digestion in the biogas reactor. It was found in batch experiments that bacterial pathogens showed the highest relative abundance and richness after 30 days' post-digestion. Streptococcus bovis was found in all the samples. Our results showed that special attention should be paid to the post-digestion since the increase in relative abundance of bacterial pathogens after post-digestion might reflect regrowth of bacterial pathogens and limit biosolids disposal vectors. Copyright © 2014 Elsevier
Some of the most deadly bacterial diseases, including leprosy, anthrax and plague, are caused by bacterial lineages with extremely low levels of genetic diversity, the so-called ‘genetically monomorphic bacteria’. It has only become possible to analyse the population genetics of such bacteria since the recent advent of high-throughput comparative genomics. The genomes of genetically monomorphic lineages contain very few polymorphic sites, which often reflect unambiguous clonal genealogies. Some genetically monomorphic lineages have evolved in the last decades, e.g. antibiotic-resistant Staphylococcus aureus, whereas others have evolved over several millennia, e.g. the cause of plague, Yersinia pestis. Based on recent results, it is now possible to reconstruct the sources and the history of pandemic waves of plague by a combined analysis of phylogeographic signals in Y. pestis plus polymorphisms found in ancient DNA. Different from historical accounts based exclusively on human disease, Y. pestis evolved in China, or the vicinity, and has spread globally on multiple occasions. These routes of transmission can be reconstructed from the genealogy, most precisely for the most recent pandemic that was spread from Hong Kong in multiple independent waves in 1894. PMID:22312053
Stirling, J; Griffith, M; Blair, I; Cormican, M; Dooley, J S G; Goldsmith, C E; Glover, S G; Loughrey, A; Lowery, C J; Matsuda, M; McClurg, R; McCorry, K; McDowell, D; McMahon, A; Cherie Millar, B; Nagano, Y; Rao, J R; Rooney, P J; Smyth, M; Snelling, W J; Xu, J; Moore, J E
Faecal prevalence of gastrointestinal bacterial pathogens, including Campylobacter, Escherichia coli O157:H7, Salmonella, Shigella, Yersinia, as well as Arcobacter, were examined in 317 faecal specimens from 44 animal species in Belfast Zoological Gardens, during July-September 2006. Thermophilic campylobacters including Campylobacter jejuni, Campylobacter coli and Campylobacter lari, were the most frequently isolated pathogens, where members of this genus were isolated from 11 animal species (11 of 44; 25%). Yersinia spp. were isolated from seven animal species (seven of 44; 15.9%) and included, Yersinia enterocolitica (five of seven isolates; 71.4%) and one isolate each of Yersinia frederiksenii and Yersinia kristensenii. Only one isolate of Salmonella was obtained throughout the entire study, which was an isolate of Salmonella dublin (O 1,9,12: H g, p), originating from tiger faeces after enrichment. None of the animal species found in public contact areas of the zoo were positive for any gastrointestinal bacterial pathogens. Also, water from the lake in the centre of the grounds, was examined for the same bacterial pathogens and was found to contain C. jejuni. This study is the first report on the isolation of a number of important bacterial pathogens from a variety of novel host species, C. jejuni from the red kangaroo (Macropus rufus), C. lari from a maned wolf (Chrysocyon brachyurus), Y. kristensenii from a vicugna (Vicugna vicugna) and Y. enterocolitica from a maned wolf and red panda (Ailurus fulgens). In conclusion, this study demonstrated that the faeces of animals in public contact areas of the zoo were not positive for the bacterial gastrointestinal pathogens examined. This is reassuring for the public health of visitors, particularly children, who enjoy this educational and recreational resource.
Bernard, Quentin; Smith, Alexis A; Yang, Xiuli; Koci, Juraj; Foor, Shelby D; Cramer, Sarah D; Zhuang, Xuran; Dwyer, Jennifer E; Lin, Yi-Pin; Mongodin, Emmanuel F; Marques, Adriana; Leong, John M; Anguita, Juan; Pal, Utpal
Borrelia burgdorferi is one of the few extracellular pathogens capable of establishing persistent infection in mammals. The mechanisms that sustain long-term survival of this bacterium are largely unknown. Here we report a unique innate immune evasion strategy of B. burgdorferi , orchestrated by a surface protein annotated as BBA57, through its modulation of multiple spirochete virulent determinants. BBA57 function is critical for early infection but largely redundant for later stages of spirochetal persistence, either in mammals or in ticks. The protein influences host IFN responses as well as suppresses multiple host microbicidal activities involving serum complement, neutrophils, and antimicrobial peptides. We also discovered a remarkable plasticity in BBA57-mediated spirochete immune evasion strategy because its loss, although resulting in near clearance of pathogens at the inoculum site, triggers nonheritable adaptive changes that exclude detectable nucleotide alterations in the genome but incorporate transcriptional reprograming events. Understanding the malleability in spirochetal immune evasion mechanisms that ensures their host persistence is critical for the development of novel therapeutic and preventive approaches to combat long-term infections like Lyme borreliosis.
Kirsch, Petra; Jores, Jörg; Wieler, Lothar H
Many bacterial virulence attributes, like toxins, adhesins, invasins, iron uptake systems, are encoded within specific regions of the bacterial genome. These in size varying regions are termed pathogenicity islands (PAIs) since they confer pathogenic properties to the respective micro-organism. Per definition PAIs are exclusively found in pathogenic strains and are often inserted near transfer-RNA genes. Nevertheless, non-pathogenic bacteria also possess foreign DNA elements that confer advantageous features, leading to improved fitness. These additional DNA elements as well as PAIs are termed genomic islands and were acquired during bacterial evolution. Significant G+C content deviation in pathogenicity islands with respect to the rest of the genome, the presence of direct repeat sequences at the flanking regions, the presence of integrase gene determinants as other mobility features,the particular insertion site (tRNA gene) as well as the observed genetic instability suggests that pathogenicity islands were acquired by horizontal gene transfer. PAIs are the fascinating proof of the plasticity of bacterial genomes. PAIs were originally described in human pathogenic Escherichia (E.) coli strains. In the meantime PAIs have been found in various pathogenic bacteria of humans, animals and even plants. The Locus of Enterocyte Effacement (LEE) is one particular widely distributed PAI of E coli. In addition, it also confers pathogenicity to the related species Citrobacter (C.) rodentium and Escherichia (E.) alvei. The LEE is an important virulence feature of several animal pathogens. It is an obligate PAI of all animal and human enteropathogenic E. coli (EPEC), and most enterohaemorrhegic E. coli (EHEC) also harbor the LEE. The LEE encodes a type III secretion system, an adhesion (intimin) that mediates the intimate contact between the bacterium and the epithelial cell, as well as various proteins which are secreted via the type III secretion system. The LEE encoded
Yao, Jiangwei; Rock, Charles O.
Bacterial type II fatty acid synthesis (FASII) is a target for the development of novel therapeutics. Bacteria incorporate extracellular fatty acids into membrane lipids, raising the question of whether pathogens use host fatty acids to bypass FASII and defeat FASII therapeutics. Some pathogens suppress FASII when exogenous fatty acids are present to bypass FASII therapeutics. FASII inhibition cannot be bypassed in many bacteria because essential fatty acids cannot be obtained from the host. FASII antibiotics may not be effective against all bacteria, but a broad spectrum of Gram-negative and -positive pathogens can be effectively treated with FASII inhibitors. PMID:25648887
Beattie, Gwyn A
This review examines the many ways in which water influences the relations between foliar bacterial pathogens and plants. As a limited resource in aerial plant tissues, water is subject to manipulation by both plants and pathogens. A model is emerging that suggests that plants actively promote localized desiccation at the infection site and thus restrict pathogen growth as one component of defense. Similarly, many foliar pathogens manipulate water relations as one component of pathogenesis. Nonvascular pathogens do this using effectors and other molecules to alter hormonal responses and enhance intercellular watersoaking, whereas vascular pathogens use many mechanisms to cause wilt. Because of water limitations on phyllosphere surfaces, bacterial colonists, including pathogens, benefit from the protective effects of cellular aggregation, synthesis of hygroscopic polymers, and uptake and production of osmoprotective compounds. Moreover, these bacteria employ tactics for scavenging and distributing water to overcome water-driven barriers to nutrient acquisition, movement, and signal exchange on plant surfaces. Copyright © 2011 by Annual Reviews. All rights reserved.
Fire blight is a devastating disease of apple (Malus x domestica) caused by the bacterial pathogen Erwinia amylovora (Ea). When infiltrated into host leaves, Ea induces reactions similar to a hypersensitive response (HR). Type III (T3SS) associated effectors, especially DspA/E, are suspected to ha...
Biological soil amendments (BSA’s) like manure and compost are frequently used as organic fertilizers to soils to improve its physical and chemical properties. However, BSAs have been known to be a reservoir for enteric bacterial pathogens like enterohemorrhagic E. coli, Salmonella spp, and Listeri...
Bacterial foodborne diseases are caused by consumption of foods contaminated with bacteria and/or their toxins. In this study, we evaluated antibacterial properties of twelve different extracts including turmeric, lemon and different kinds of teas against four major pathogenic foodborne bacteria inc...
The Quantum II, originally designed by Abbott Diagnostics for automated rapid identification of members of Enterobacteriaceae, was adapted for the identification of bacterial fish pathogens. he instrument operates as a spectrophotometer at a wavelength of 492.600 nm. ample cartri...
Bacterial stem blight of alfalfa occurs sporadically in the central and western U.S. Yield losses of up to 50% of the first harvest can occur with some cultivars. Developing resistant cultivars is hampered by lack of information on the pathogen and a standard test for evaluating plant germplasm. Bac...
Gram-negative bacterial pathogens of eukaryotes often secrete proteins directly into host cells via a needle-like protein channel called a ‘type III secretion system’ (T3SS). Bacteria that are adapted to either animal or plant hosts use phylogenetically distinct T3SSs for secreting proteins. Here, ...
Karavolos, Michail H; Winzer, Klaus; Williams, Paul; Khan, C M Anjam
The interactions between bacterial pathogens and their eukaryotic hosts are vital in determining the outcome of infections. Bacterial pathogens employ molecular sensors to detect and facilitate adaptation to changes in their niche. The sensing of these extracellular signals enables the pathogen to navigate within mammalian hosts. Intercellular bacterial communication is facilitated by the production and sensing of autoinducer (AI) molecules via quorum sensing. More recently, AI-3 and the host neuroendocrine (NE) hormones adrenaline and noradrenaline were reported to display cross-talk for the activation of the same signalling pathways. Remarkably, there is increasing evidence to suggest that enteric bacteria sense and respond to the host NE stress hormones adrenaline and noradrenaline to modulate virulence. These responses can be inhibited by α and β-adrenergic receptor antagonists implying a bacterial receptor-based sensing and signalling cascade. In Escherichia coli O157:H7 and Salmonella, QseC has been proposed as the adrenergic receptor. Strikingly, there is an increasing body of evidence that not all the bacterial adrenergic responses require signalling through QseC. Here we provide additional hypotheses to reconcile these observations implicating the existence of alternative adrenergic receptors including BasS, QseE and CpxA and their associated signalling cascades with major roles in interkingdom communication. © 2012 Blackwell Publishing Ltd.
Caza, Mélissa; Kronstad, James W.
Iron is the most abundant transition metal in the human body and its bioavailability is stringently controlled. In particular, iron is tightly bound to host proteins such as transferrin to maintain homeostasis, to limit potential damage caused by iron toxicity under physiological conditions and to restrict access by pathogens. Therefore, iron acquisition during infection of a human host is a challenge that must be surmounted by every successful pathogenic microorganism. Iron is essential for bacterial and fungal physiological processes such as DNA replication, transcription, metabolism, and energy generation via respiration. Hence, pathogenic bacteria and fungi have developed sophisticated strategies to gain access to iron from host sources. Indeed, siderophore production and transport, iron acquisition from heme and host iron-containing proteins such as hemoglobin and transferrin, and reduction of ferric to ferrous iron with subsequent transport are all strategies found in bacterial and fungal pathogens of humans. This review focuses on a comparison of these strategies between bacterial and fungal pathogens in the context of virulence and the iron limitation that occurs in the human body as a mechanism of innate nutritional defense. PMID:24312900
Han, Barbara A.; Schmidt, John Paul; Bowden, Sarah E.; Drake, John M.
The increasing frequency of zoonotic disease events underscores a need to develop forecasting tools toward a more preemptive approach to outbreak investigation. We apply machine learning to data describing the traits and zoonotic pathogen diversity of the most speciose group of mammals, the rodents, which also comprise a disproportionate number of zoonotic disease reservoirs. Our models predict reservoir status in this group with over 90% accuracy, identifying species with high probabilities of harboring undiscovered zoonotic pathogens based on trait profiles that may serve as rules of thumb to distinguish reservoirs from nonreservoir species. Key predictors of zoonotic reservoirs include biogeographical properties, such as range size, as well as intrinsic host traits associated with lifetime reproductive output. Predicted hotspots of novel rodent reservoir diversity occur in the Middle East and Central Asia and the Midwestern United States. PMID:26038558
Crowder, Chris D.; Rounds, Megan A.; Phillipson, Curtis A.; Picuri, John M.; Matthews, Heather E.; Halverson, Justina; Schutzer, Steven E.; Ecker, David J.; Eshoo, Mark W.
Ticks harbor numerous bacterial, protozoal, and viral pathogens that can cause serious infections in humans and domestic animals. Active surveillance of the tick vector can provide insight into the frequency and distribution of important pathogens in the environment. Nucleic-acid based detection of tick-borne bacterial, protozoan, and viral pathogens requires the extraction of both DNA and RNA (total nucleic acids) from ticks. Traditional methods for nucleic acid extraction are limited to extraction of either DNA or the RNA from a sample. Here we present a simple bead-beating based protocol for extraction of DNA and RNA from a single tick and show detection of Borrelia burgdorferi and Powassan virus from individual, infected Ixodes scapularis ticks. We determined expected yields for total nucleic acids by this protocol for a variety of adult tick species. The method is applicable to a variety of arthropod vectors, including fleas and mosquitoes, and was partially automated on a liquid handling robot. PMID:20180313
Eason, Mia M; Fan, Xin
Respiratory tract bacterial pathogens are the etiologic agents of a variety of illnesses. The ability of these bacteria to cause disease is imparted through survival within the host and avoidance of pathogen clearance by the immune system. Respiratory tract pathogens are continually bombarded by reactive oxygen species (ROS), which may be produced by competing bacteria, normal metabolic function, or host immunological responses. In order to survive and proliferate, bacteria have adapted defense mechanisms to circumvent the effects of ROS. Bacteria employ the use of anti-oxidant enzymes, catalases and catalase-peroxidases, to relieve the effects of the oxidative stressors to which they are continually exposed. The decomposition of ROS has been shown to provide favorable conditions in which respiratory tract opportunistic bacterial pathogens such as Haemophilus influenzae, Mycobacterium tuberculosis, Legionella pneumophila, and Neisseria meningitidis are able to withstand exposure to highly reactive molecules and yet survive. Bacteria possessing mutations in the catalase gene have a decreased survival rate, yet may be able to compensate for the lack of catalatic activity if peroxidatic activity is present. An incomplete knowledge of the mechanisms by which catalase and catalase-peroxidases are regulated still persists, however, in some bacterial species, a regulatory factor known as OxyR has been shown to either up-regulate or down-regulate catalase gene expression. Yet, more research is still needed to increase the knowledge base in relation to this enzyme class. As with this review, we focus on major respiratory tract opportunistic bacterial pathogens in order to elucidate the function and regulation of catalases. The importance of the research could lead to the development of novel treatments against respiratory bacterial infections. Copyright © 2014 Elsevier Ltd. All rights reserved.
Wagner, Karoline; Springer, Burkard; Imkamp, Frank; Opota, Onya; Greub, Gilbert; Keller, Peter M
Pneumonia is a severe infectious disease. In addition to common viruses and bacterial pathogens (e.g. Streptococcus pneumoniae), fastidious respiratory pathogens like Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella spp. can cause severe atypical pneumonia. They do not respond to penicillin derivatives, which may cause failure of antibiotic empirical therapy. The same applies for infections with B. pertussis and B. parapertussis, the cause of pertussis disease, that may present atypically and need to be treated with macrolides. Moreover, these fastidious bacteria are difficult to identify by culture or serology, and therefore often remain undetected. Thus, rapid and accurate identification of bacterial pathogens causing atypical pneumonia is crucial. We performed a retrospective method evaluation study to evaluate the diagnostic performance of the new, commercially available Lightmix ® multiplex RT-PCR assay that detects these fastidious bacterial pathogens causing atypical pneumonia. In this retrospective study, 368 clinical respiratory specimens, obtained from patients suffering from atypical pneumonia that have been tested negative for the presence of common agents of pneumonia by culture and viral PCR, were investigated. These clinical specimens have been previously characterized by singleplex RT-PCR assays in our diagnostic laboratory and were used to evaluate the diagnostic performance of the respiratory multiplex Lightmix ® RT-PCR. The multiplex RT-PCR displayed a limit of detection between 5 and 10 DNA copies for different in-panel organisms and showed identical performance characteristics with respect to specificity and sensitivity as in-house singleplex RT-PCRs for pathogen detection. The Lightmix ® multiplex RT-PCR assay represents a low-cost, time-saving and accurate diagnostic tool with high throughput potential. The time-to-result using an automated DNA extraction device for respiratory specimens followed by multiplex RT-PCR detection was
Duvenage, Francois J; Duvenage, Stacey; Du Plessis, Erika M; Volschenk, Quinton; Korsten, Lise
Knowledge on the culturable bacteria and foodborne pathogen presence on pears is important for understanding the impact of postharvest practices on food safety assurance. Pear fruit bacteria were investigated from the point of harvest, following chlorine drenching and after controlled atmosphere (CA) storage to assess the impact on natural bacterial populations and potential foodborne pathogens. Salmonella spp. and Listeria monocytogenes were detected on freshly harvested fruit in season one. During season one, chemical drenching and CA storage did not have a significant effect on the bacterial load of orchard pears, except for two farms where the populations were lower 'after CA storage'. During season two, bacterial populations of orchard pears from three of the four farms increased significantly following drenching; however, the bacterial load decreased 'after CA storage'. Bacteria isolated following enumeration included Enterobacteriaceae, Microbacteriaceae, Pseudomonadaceae and Bacillaceae, with richness decreasing 'after drench' and 'after CA storage'. Salmonella spp. and L. monocytogenes were not detected after postharvest practices. Postharvest practices resulted in decreased bacterial species richness. Understanding how postharvest practices have an impact on the viable bacterial populations of pear fruit will contribute to the development of crop-specific management systems for food safety assurance. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.
Kerk, David; Uhrig, R Glen; Moorhead, Greg B
Reversible phosphorylation is a widespread modification affecting the great majority of eukaryotic cellular proteins, and whose effects influence nearly every cellular function. Protein phosphatases are increasingly recognized as exquisitely regulated contributors to these changes. The PPP (phosphoprotein phosphatase) family comprises enzymes, which catalyze dephosphorylation at serine and threonine residues. Nearly a decade ago, "bacterial-like" enzymes were recognized with similarity to proteins from various bacterial sources: SLPs (Shewanella-like phosphatases), RLPHs (Rhizobiales-like phosphatases), and ALPHs (ApaH-like phosphatases). A recent article from our laboratory appearing in Plant Physiology characterizes their extensive organismal distribution, abundance in plant species, predicted subcellular localization, motif organization, and sequence evolution. One salient observation is the distinct evolutionary trajectory followed by SLP genes and proteins in photosynthetic eukaryotes vs. animal and plant pathogens derived from photosynthetic ancestors. We present here a closer look at sequence data that emphasizes the distinctiveness of pathogen SLP proteins and that suggests that they might represent novel drug targets. A second observation in our original report was the high degree of similarity between the bacterial-like PPPs of eukaryotes and closely related proteins of the "eukaryotic-like" phyla Myxococcales and Planctomycetes. We here reflect on the possible implications of these observations and their importance for future research.
Amanzougaghene, Nadia; Fenollar, Florence; Sangaré, Abdoul Karim; Sissoko, Mahamadou S.; Doumbo, Ogobara K.; Raoult, Didier
In poor African countries, where no medical and biological facilities are available, the identification of potential emerging pathogens of concern at an early stage is challenging. Head lice, Pediculus humanus capitis, have a short life, feed only on human blood and do not transmit pathogens to their progeny. They are, therefore, a perfect tool for the xenodiagnosis of current or recent human infection. This study assessed the occurrence of bacterial pathogens from head lice collected in two rural villages from Mali, where a high frequency of head lice infestation had previously been reported, using molecular methods. Results show that all 600 head lice, collected from 117 individuals, belonged to clade E, specific to West Africa. Bartonella quintana, the causative agent of trench fever, was identified in three of the 600 (0.5%) head lice studied. Our study also shows, for the first time, the presence of the DNA of two pathogenic bacteria, namely Coxiella burnetii (5.1%) and Rickettsia aeschlimannii (0.6%), detected in human head lice, as well as the DNA of potential new species from the Anaplasma and Ehrlichia genera of unknown pathogenicity. The finding of several Malian head lice infected with B. quintana, C. burnetii, R. aeschlimannii, Anaplasma and Ehrlichia is alarming and highlights the need for active survey programs to define the public health consequences of the detection of these emerging bacterial pathogens in human head lice. PMID:28931077
Amanzougaghene, Nadia; Fenollar, Florence; Sangaré, Abdoul Karim; Sissoko, Mahamadou S; Doumbo, Ogobara K; Raoult, Didier; Mediannikov, Oleg
In poor African countries, where no medical and biological facilities are available, the identification of potential emerging pathogens of concern at an early stage is challenging. Head lice, Pediculus humanus capitis, have a short life, feed only on human blood and do not transmit pathogens to their progeny. They are, therefore, a perfect tool for the xenodiagnosis of current or recent human infection. This study assessed the occurrence of bacterial pathogens from head lice collected in two rural villages from Mali, where a high frequency of head lice infestation had previously been reported, using molecular methods. Results show that all 600 head lice, collected from 117 individuals, belonged to clade E, specific to West Africa. Bartonella quintana, the causative agent of trench fever, was identified in three of the 600 (0.5%) head lice studied. Our study also shows, for the first time, the presence of the DNA of two pathogenic bacteria, namely Coxiella burnetii (5.1%) and Rickettsia aeschlimannii (0.6%), detected in human head lice, as well as the DNA of potential new species from the Anaplasma and Ehrlichia genera of unknown pathogenicity. The finding of several Malian head lice infected with B. quintana, C. burnetii, R. aeschlimannii, Anaplasma and Ehrlichia is alarming and highlights the need for active survey programs to define the public health consequences of the detection of these emerging bacterial pathogens in human head lice.
Forde, Taya L.; Orsel, Karin; Zadoks, Ruth N.; Biek, Roman; Adams, Layne G.; Checkley, Sylvia L.; Davison, Tracy; De Buck, Jeroen; Dumond, Mathieu; Elkin, Brett T.; Finnegan, Laura; Macbeth, Bryan J.; Nelson, Cait; Niptanatiak, Amanda; Sather, Shane; Schwantje, Helen M.; van der Meer, Frank; Kutz, Susan J.
Northern ecosystems are currently experiencing unprecedented ecological change, largely driven by a rapidly changing climate. Pathogen range expansion, and emergence and altered patterns of infectious disease, are increasingly reported in wildlife at high latitudes. Understanding the causes and consequences of shifting pathogen diversity and host-pathogen interactions in these ecosystems is important for wildlife conservation, and for indigenous populations that depend on wildlife. Among the key questions are whether disease events are associated with endemic or recently introduced pathogens, and whether emerging strains are spreading throughout the region. In this study, we used a phylogenomic approach to address these questions of pathogen endemicity and spread for Erysipelothrix rhusiopathiae, an opportunistic multi-host bacterial pathogen associated with recent mortalities in arctic and boreal ungulate populations in North America. We isolated E. rhusiopathiae from carcasses associated with large-scale die-offs of muskoxen in the Canadian Arctic Archipelago, and from contemporaneous mortality events and/or population declines among muskoxen in northwestern Alaska and caribou and moose in western Canada. Bacterial genomic diversity differed markedly among these locations; minimal divergence was present among isolates from muskoxen in the Canadian Arctic, while in caribou and moose populations, strains from highly divergent clades were isolated from the same location, or even from within a single carcass. These results indicate that mortalities among northern ungulates are not associated with a single emerging strain of E. rhusiopathiae, and that alternate hypotheses need to be explored. Our study illustrates the value and limitations of bacterial genomic data for discriminating between ecological hypotheses of disease emergence, and highlights the importance of studying emerging pathogens within the broader context of environmental and host factors.
Coy, Monique R.; Stelinski, Lukasz L.; Pelz-Stelinski, Kirsten S.
The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movement of vectors is likely manipulated by a bacterial plant pathogen. We investigated how Candidatus Liberibacter asiaticus (CLas) affects dispersal behavior, flight capacity, and the sexual attraction of its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama). CLas is the putative causal agent of huanglongbing (HLB), which is a disease that threatens the viability of commercial citrus production worldwide. When D. citri developed on CLas-infected plants, short distance dispersal of male D. citri was greater compared to counterparts reared on uninfected plants. Flight by CLas-infected D. citri was initiated earlier and long flight events were more common than by uninfected psyllids, as measured by a flight mill apparatus. Additionally, CLas titers were higher among psyllids that performed long flights than psyllid that performed short flights. Finally, attractiveness of female D. citri that developed on infected plants to male conspecifics increased proportionally with increasing CLas bacterial titers measured within female psyllids. Our study indicates that the phytopathogen, CLas, may manipulate movement and mate selection behavior of their vectors, which is a possible evolved mechanism to promote their own spread. These results have global implications for both current HLB models of disease spread and control strategies. PMID:26083763
Chapuis, Élodie; Pagès, Sylvie; Emelianoff, Vanya; Givaudan, Alain; Ferdy, Jean-Baptiste
The trade-off hypothesis proposes that the evolution of pathogens' virulence is shaped by a link between virulence and contagiousness. This link is often assumed to come from the fact that pathogens are contagious only if they can reach high parasitic load in the infected host. In this paper we present an experimental test of the hypothesis that selection on fast replication can affect virulence. In a serial passage experiment, we selected 80 lines of the bacterial insect-pathogen Xenorhabdus nematophila to multiply fast in an artificial culture medium. This selection resulted in shortened lag phase in our selected bacteria. We then injected these bacteria into insects and observed an increase in virulence. This could be taken as a sign that virulence in Xenorhabdus is linked to fast multiplication. But we found, among the selected lineages, either no link or a positive correlation between lag duration and virulence: the most virulent bacteria were the last to start multiplying. We then surveyed phenotypes that are under the control of the flhDC super regulon, which has been shown to be involved in Xenorhabdus virulence. We found that, in one treatment, the flhDC regulon has evolved rapidly, but that the changes we observed were not connected to virulence. All together, these results indicate that virulence is, in Xenorhabdus as in many other pathogens, a multifactorial trait. Being able to grow fast is one way to be virulent. But other ways exist which renders the evolution of virulence hard to predict.
Sistrunk, Jeticia R.; Nickerson, Kourtney P.; Chanin, Rachael B.; Rasko, David A.
SUMMARY Bacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual infection cycle. For enteric pathogens, the ability to adapt to numerous host factors under the harsh conditions of the gastrointestinal tract is critical for establishing infection. One such host factor readily encountered by enteric bacteria is bile, an innately antimicrobial detergent-like compound essential for digestion and nutrient absorption. Not only have enteric pathogens evolved to resist the bactericidal conditions of bile, but these bacteria also utilize bile as a signal to enhance virulence regulation for efficient infection. This review provides a comprehensive and up-to-date analysis of bile-related research with enteric pathogens. From common responses to the unique expression of specific virulence factors, each pathogen has overcome significant challenges to establish infection in the gastrointestinal tract. Utilization of bile as a signal to modulate virulence factor expression has led to important insights for our understanding of virulence mechanisms for many pathogens. Further research on enteric pathogens exposed to this in vivo signal will benefit therapeutic and vaccine development and ultimately enhance our success at combating such elite pathogens. PMID:27464994
Guo, Ling-Yun; Zhang, Zhi-Xiao; Wang, Xi; Zhang, Ping-Ping; Shi, Wei; Yao, Kai-Hu; Liu, Lin-Lin; Liu, Gang; Yang, Yong-Hong
To explore the clinical characteristics and analyze the pathogens of bacterial meningitis in children. Bacterial meningitis cases occurring from January 2010 through December 2014 at Beijing Children's Hospital were reviewed retrospectively. The records of all patients, including data on clinical features and laboratory information, were obtained and analyzed. In total, the cases of 507 pediatric patients seen over a 5-year period were analyzed; 220 of these cases were etiologically confirmed. These patients were classified into four age groups: 29 days to 1 year (n=373, 73.6%), 1-3 years (n=61, 12.0%), 3-6 years (n=41, 8.1%), and >6 years (n=32, 6.3%). The main pathogens identified in this study were Streptococcus pneumoniae (n=73, 33.2%), Escherichia coli (n=24, 10.9%), Enterococcus (n=22, 10.0%), and group B Streptococcus (n=18, 8.2%). All Gram-positive bacteria were sensitive to vancomycin and linezolid. All Gram-negative bacteria were sensitive to meropenem. The total non-susceptibility rate of S. pneumoniae to penicillin was 47.6% (20/42). The resistance rates to ceftriaxone, cefepime, and ceftazidime were 75% (9/12), 55.6% (5/9), and 40% (4/10), respectively. The main pathogen of bacterial meningitis in this study was S. pneumoniae. The antibiotic resistance rates among children with bacterial meningitis are of serious concern. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.
Dobrowsky, P. H.; De Kwaadsteniet, M.; Cloete, T. E.
The harvesting of rainwater is gaining acceptance among many governmental authorities in countries such as Australia, Germany, and South Africa, among others. However, conflicting reports on the microbial quality of harvested rainwater have been published. To monitor the presence of potential pathogenic bacteria during high-rainfall periods, rainwater from 29 rainwater tanks was sampled on four occasions (during June and August 2012) in a sustainable housing project in Kleinmond, South Africa. This resulted in the collection of 116 harvested rainwater samples in total throughout the sampling period. The identities of the dominant, indigenous, presumptive pathogenic isolates obtained from the rainwater samples throughout the sampling period were confirmed through universal 16S rRNA PCR, and the results revealed that Pseudomonas (19% of samples) was the dominant genus isolated, followed by Aeromonas (16%), Klebsiella (11%), and Enterobacter (9%). PCR assays employing genus-specific primers also confirmed the presence of Aeromonas spp. (16%), Klebsiella spp. (47%), Legionella spp. (73%), Pseudomonas spp. (13%), Salmonella spp. (6%), Shigella spp. (27%), and Yersinia spp. (28%) in the harvested rainwater samples. In addition, on one sampling occasion, Giardia spp. were detected in 25% of the eight tank water samples analyzed. This study highlights the diverse array of pathogenic bacteria that persist in harvested rainwater during high-rainfall periods. The consumption of untreated harvested rainwater could thus pose a potential significant health threat to consumers, especially children and immunocompromised individuals, and it is recommended that harvested rainwater be treated for safe usage as an alternative water source. PMID:24487540
Sherwood, Racquel Kim; Roy, Craig R
The ability to create and maintain a specialized organelle that supports bacterial replication is an important virulence property for many intracellular pathogens. Living in a membrane-bound vacuole presents inherent challenges, including the need to remodel a plasma membrane-derived organelle into a novel structure that will expand and provide essential nutrients to support replication, while also having the vacuole avoid membrane transport pathways that target bacteria for destruction in lysosomes. It is clear that pathogenic bacteria use different strategies to accomplish these tasks. The dynamics by which host Rab GTPases associate with pathogen-occupied vacuoles provide insight into the mechanisms used by different bacteria to manipulate host membrane transport. In this review we highlight some of the strategies bacteria use to maintain a pathogen-occupied vacuole by focusing on the Rab proteins involved in biogenesis and maintenance of these novel organelles. Copyright © 2013 Elsevier Inc. All rights reserved.
Criss, Alison K.; Seifert, H. Steven
Preface Neisseria gonorrhoeae and Neisseria meningitidis are Gram-negative bacterial pathogens that are exquisitely adapted for growth at human mucosal surfaces and for efficient transmission between hosts. One factor that is essential to neisserial pathogenesis is the interaction between the bacteria and neutrophils, which are recruited in high numbers during infection. Although this vigorous host response could simply reflect effective immune recognition of the bacteria, there is mounting evidence that in fact these obligate human pathogens manipulate the innate immune response to promote infectious processes. This Review summarizes the mechanisms used by pathogenic neisseriae to resist and modulate the antimicrobial activities of neutrophils. It also details some of the major outstanding questions about the Neisseria–neutrophil relationship and proposes potential benefits of this relationship for the pathogen. PMID:22290508
Fu, Yue; Chang, Feng-Ming James; Giedroc, David P
CONSPECTUS: The human innate immune system has evolved the means to reduce the bioavailability of first-row late d-block transition metal ions to invading microbial pathogens in a process termed "nutritional immunity". Transition metals from Mn(II) to Zn(II) function as metalloenzyme cofactors in all living cells, and the successful pathogen is capable of mounting an adaptive response to mitigate the effects of host control of transition metal bioavailability. Emerging evidence suggests that Mn, Fe, and Zn are withheld from the pathogen in classically defined nutritional immunity, while Cu is used to kill invading microorganisms. This Account summarizes new molecular-level insights into copper trafficking across cell membranes from studies of a number of important bacterial pathogens and model organisms, including Escherichia coli, Salmonella species, Mycobacterium tuberculosis, and Streptococcus pneumoniae, to illustrate general principles of cellular copper resistance. Recent highlights of copper chemistry at the host-microbial pathogen interface include the first high resolution structures and functional characterization of a Cu(I)-effluxing P1B-ATPase, a new class of bacterial copper chaperone, a fungal Cu-only superoxide dismutase SOD5, and the discovery of a small molecule Cu-bound SOD mimetic. Successful harnessing by the pathogen of host-derived bactericidal Cu to reduce the bacterial load of reactive oxygen species (ROS) is an emerging theme; in addition, recent studies continue to emphasize the importance of short lifetime protein-protein interactions that orchestrate the channeling of Cu(I) from donor to target without dissociation into bulk solution; this, in turn, mitigates the off-pathway effects of Cu(I) toxicity in both the periplasm in Gram negative organisms and in the bacterial cytoplasm. It is unclear as yet, outside of the photosynthetic bacteria, whether Cu(I) is trafficked to other cellular destinations, for example, to cuproenzymes or other
Mikonranta, Lauri; Mappes, Johanna; Laakso, Jouni; Ketola, Tarmo
Pathogens evolve in a close antagonistic relationship with their hosts. The conventional theory proposes that evolution of virulence is highly dependent on the efficiency of direct host-to-host transmission. Many opportunistic pathogens, however, are not strictly dependent on the hosts due to their ability to reproduce in the free-living environment. Therefore it is likely that conflicting selection pressures for growth and survival outside versus within the host, rather than transmission potential, shape the evolution of virulence in opportunists. We tested the role of within-host selection in evolution of virulence by letting a pathogen Serratia marcescens db11 sequentially infect Drosophila melanogaster hosts and then compared the virulence to strains that evolved only in the outside-host environment. We found that the pathogen adapted to both Drosophila melanogaster host and novel outside-host environment, leading to rapid evolutionary changes in the bacterial life-history traits including motility, in vitro growth rate, biomass yield, and secretion of extracellular proteases. Most significantly, selection within the host led to decreased virulence without decreased bacterial load while the selection lines in the outside-host environment maintained the same level of virulence with ancestral bacteria. This experimental evidence supports the idea that increased virulence is not an inevitable consequence of within-host adaptation even when the epidemiological restrictions are removed. Evolution of attenuated virulence could occur because of immune evasion within the host. Alternatively, rapid fluctuation between outside-host and within-host environments, which is typical for the life cycle of opportunistic bacterial pathogens, could lead to trade-offs that lower pathogen virulence.
Canova, Marc J.; Molle, Virginie
In bacterial pathogenesis, monitoring and adapting to the dynamically changing environment in the host and an ability to disrupt host immune responses are critical. The virulence determinants of pathogenic bacteria include the sensor/signaling proteins of the serine/threonine protein kinase (STPK) family that have a dual role of sensing the environment and subverting specific host defense processes. STPKs can sense a wide range of signals and coordinate multiple cellular processes to mount an appropriate response. Here, we review some of the well studied bacterial STPKs that are essential virulence factors and that modify global host responses during infection. PMID:24554701
Canova, Marc J; Molle, Virginie
In bacterial pathogenesis, monitoring and adapting to the dynamically changing environment in the host and an ability to disrupt host immune responses are critical. The virulence determinants of pathogenic bacteria include the sensor/signaling proteins of the serine/threonine protein kinase (STPK) family that have a dual role of sensing the environment and subverting specific host defense processes. STPKs can sense a wide range of signals and coordinate multiple cellular processes to mount an appropriate response. Here, we review some of the well studied bacterial STPKs that are essential virulence factors and that modify global host responses during infection.
Arrieta-Ortiz, Mario L; Rodríguez-R, Luis M; Pérez-Quintero, Álvaro L; Poulin, Lucie; Díaz, Ana C; Arias Rojas, Nathalia; Trujillo, Cesar; Restrepo Benavides, Mariana; Bart, Rebecca; Boch, Jens; Boureau, Tristan; Darrasse, Armelle; David, Perrine; Dugé de Bernonville, Thomas; Fontanilla, Paula; Gagnevin, Lionel; Guérin, Fabien; Jacques, Marie-Agnès; Lauber, Emmanuelle; Lefeuvre, Pierre; Medina, Cesar; Medina, Edgar; Montenegro, Nathaly; Muñoz Bodnar, Alejandra; Noël, Laurent D; Ortiz Quiñones, Juan F; Osorio, Daniela; Pardo, Carolina; Patil, Prabhu B; Poussier, Stéphane; Pruvost, Olivier; Robène-Soustrade, Isabelle; Ryan, Robert P; Tabima, Javier; Urrego Morales, Oscar G; Vernière, Christian; Carrere, Sébastien; Verdier, Valérie; Szurek, Boris; Restrepo, Silvia; López, Camilo; Koebnik, Ralf; Bernal, Adriana
Xanthomonas axonopodis pv. manihotis (Xam) is the causal agent of bacterial blight of cassava, which is among the main components of human diet in Africa and South America. Current information about the molecular pathogenicity factors involved in the infection process of this organism is limited. Previous studies in other bacteria in this genus suggest that advanced draft genome sequences are valuable resources for molecular studies on their interaction with plants and could provide valuable tools for diagnostics and detection. Here we have generated the first manually annotated high-quality draft genome sequence of Xam strain CIO151. Its genomic structure is similar to that of other xanthomonads, especially Xanthomonas euvesicatoria and Xanthomonas citri pv. citri species. Several putative pathogenicity factors were identified, including type III effectors, cell wall-degrading enzymes and clusters encoding protein secretion systems. Specific characteristics in this genome include changes in the xanthomonadin cluster that could explain the lack of typical yellow color in all strains of this pathovar and the presence of 50 regions in the genome with atypical nucleotide composition. The genome sequence was used to predict and evaluate 22 variable number of tandem repeat (VNTR) loci that were subsequently demonstrated as polymorphic in representative Xam strains. Our results demonstrate that Xanthomonas axonopodis pv. manihotis strain CIO151 possesses ten clusters of pathogenicity factors conserved within the genus Xanthomonas. We report 126 genes that are potentially unique to Xam, as well as potential horizontal transfer events in the history of the genome. The relation of these regions with virulence and pathogenicity could explain several aspects of the biology of this pathogen, including its ability to colonize both vascular and non-vascular tissues of cassava plants. A set of 16 robust, polymorphic VNTR loci will be useful to develop a multi-locus VNTR analysis
Arrieta-Ortiz, Mario L.; Rodríguez-R, Luis M.; Pérez-Quintero, Álvaro L.; Poulin, Lucie; Díaz, Ana C.; Arias Rojas, Nathalia; Trujillo, Cesar; Restrepo Benavides, Mariana; Bart, Rebecca; Boch, Jens; Boureau, Tristan; Darrasse, Armelle; David, Perrine; Dugé de Bernonville, Thomas; Fontanilla, Paula; Gagnevin, Lionel; Guérin, Fabien; Jacques, Marie-Agnès; Lauber, Emmanuelle; Lefeuvre, Pierre; Medina, Cesar; Medina, Edgar; Montenegro, Nathaly; Muñoz Bodnar, Alejandra; Noël, Laurent D.; Ortiz Quiñones, Juan F.; Osorio, Daniela; Pardo, Carolina; Patil, Prabhu B.; Poussier, Stéphane; Pruvost, Olivier; Robène-Soustrade, Isabelle; Ryan, Robert P.; Tabima, Javier; Urrego Morales, Oscar G.; Vernière, Christian; Carrere, Sébastien; Verdier, Valérie; Szurek, Boris; Restrepo, Silvia; López, Camilo
Xanthomonas axonopodis pv. manihotis (Xam) is the causal agent of bacterial blight of cassava, which is among the main components of human diet in Africa and South America. Current information about the molecular pathogenicity factors involved in the infection process of this organism is limited. Previous studies in other bacteria in this genus suggest that advanced draft genome sequences are valuable resources for molecular studies on their interaction with plants and could provide valuable tools for diagnostics and detection. Here we have generated the first manually annotated high-quality draft genome sequence of Xam strain CIO151. Its genomic structure is similar to that of other xanthomonads, especially Xanthomonas euvesicatoria and Xanthomonas citri pv. citri species. Several putative pathogenicity factors were identified, including type III effectors, cell wall-degrading enzymes and clusters encoding protein secretion systems. Specific characteristics in this genome include changes in the xanthomonadin cluster that could explain the lack of typical yellow color in all strains of this pathovar and the presence of 50 regions in the genome with atypical nucleotide composition. The genome sequence was used to predict and evaluate 22 variable number of tandem repeat (VNTR) loci that were subsequently demonstrated as polymorphic in representative Xam strains. Our results demonstrate that Xanthomonas axonopodis pv. manihotis strain CIO151 possesses ten clusters of pathogenicity factors conserved within the genus Xanthomonas. We report 126 genes that are potentially unique to Xam, as well as potential horizontal transfer events in the history of the genome. The relation of these regions with virulence and pathogenicity could explain several aspects of the biology of this pathogen, including its ability to colonize both vascular and non-vascular tissues of cassava plants. A set of 16 robust, polymorphic VNTR loci will be useful to develop a multi-locus VNTR analysis
Awan, Uzma Azeem; Andleeb, Saiqa; Kiyani, Ayesha; Zafar, Atiya; Shafique, Irsa; Riaz, Nazia; Azhar, Muhammad Tehseen; Uddin, Hafeez
Chloroformic and isoamyl alcohol extracts of Cinnnamomum zylanicum, Cuminum cyminum, Curcuma long Linn, Trachyspermum ammi and selected standard antibiotics were investigated for their in vitro antibacterial activity against six human bacterial pathogens. The antibacterial activity was evaluated and based on the zone of inhibition using agar disc diffusion method. The tested bacterial strains were Streptococcus pyogenes, Staphylococcus epidermidis, Klebsiella pneumonia, Staphylococcus aurues, Serratia marcesnces, and Pseudomonas aeruginosa. Ciprofloxacin showed highly significant action against K. pneumonia and S. epidermidis while Ampicillin and Amoxicillin indicated lowest antibacterial activity against tested pathogens. Among the plants chloroform and isoamyl alcohol extracts of C. cyminum, S. aromaticum and C. long Linn had significant effect against P. aeruginosa, S. marcesnces and S. pyogenes. Comparison of antibacterial activity of medicinal herbs and standard antibiotics was also recorded via activity index. Used medicinal plants have various phytochemicals which reasonably justify their use as antibacterial agent.
Zhao, Xinyan; Dong, Tao
Bacterial waterborne pathogens often threaten the water safety of the drinking water system. In order to protect the health of home users, a household lab-on-a-chip (LOC) device was developed for online monitoring bacterial pathogens in drinking water, which are in accord with green design concept. The chip integrated counter-flow micromixers, a T-junction droplet generator and time-delay channels (TD-Cs), which can mix water sample and reactants into droplets in air flow and incubate the droplets in the LOC for about 18 hours before observation. The detection module was simplified into a transparent observation chamber, from which the home users can evaluate the qualitative result by naked eyes. The liquid waste generated by the LOC system was sterilized and absorbed by quicklime powders. No secondary pollution was found. The preliminary test of the prototype system met its design requirements.
Du, Songtao; Chen, I.-Hsuan; Horikawa, Shin; Lu, Xu; Liu, Yuzhe; Wikle, Howard C.; Suh, Sang Jin; Chin, Bryan A.
This paper investigates a phage-based biomolecular filter that enables the evaluation of large volumes of liquids for the presence of small quantities of bacterial pathogens. The filter is a planar arrangement of phage-coated, strip-shaped magnetoelastic (ME) biosensors (4 mm × 0.8 mm × 0.03 mm), magnetically coupled to a filter frame structure, through which a liquid of interest flows. This "phage filter" is designed to capture specific bacterial pathogens and allow non-specific debris to pass, eliminating the common clogging issue in conventional bead filters. ANSYS Maxwell was used to simulate the magnetic field pattern required to hold ME biosensors densely and to optimize the frame design. Based on the simulation results, a phage filter structure was constructed, and a proof-in-concept experiment was conducted where a Salmonella solution of known concentration were passed through the filter, and the number of captured Salmonella was quantified by plate counting.
Phaneuf, Christopher R.; Mangadu, Betty Lou Bosano; Piccini, Matthew E.; ...
Enteric and diarrheal diseases are a major cause of childhood illness and death in countries with developing economies. Each year, more than half of a million children under the age of five die from these diseases. We have developed a portable, microfluidic platform capable of simultaneous, multiplexed detection of several of the bacterial pathogens that cause these diseases. Furthermore, this platform can perform fast, sensitive immunoassays directly from relevant, complex clinical matrices such as stool without extensive sample cleanup or preparation. Using only 1 µL of sample per assay, we demonstrate simultaneous multiplexed detection of four bacterial pathogens implicated inmore » diarrheal and enteric diseases in less than 20 min.« less
Phaneuf, Christopher R.; Mangadu, Betty Lou Bosano; Piccini, Matthew E.
Enteric and diarrheal diseases are a major cause of childhood illness and death in countries with developing economies. Each year, more than half of a million children under the age of five die from these diseases. We have developed a portable, microfluidic platform capable of simultaneous, multiplexed detection of several of the bacterial pathogens that cause these diseases. Furthermore, this platform can perform fast, sensitive immunoassays directly from relevant, complex clinical matrices such as stool without extensive sample cleanup or preparation. Using only 1 µL of sample per assay, we demonstrate simultaneous multiplexed detection of four bacterial pathogens implicated inmore » diarrheal and enteric diseases in less than 20 min.« less
Alum, Absar; Rock, Channah; Abbaszadegan, Morteza
For land application, biosolids are classified as Class A or Class B based on the levels of bacterial, viral, and helminths pathogens in residual biosolids. The current EPA methods for the detection of these groups of pathogens in biosolids include discrete steps. Therefore, a separate sample is processed independently to quantify the number of each group of the pathogens in biosolids. The aim of the study was to develop a unified method for simultaneous processing of a single biosolids sample to recover bacterial, viral, and helminths pathogens. At the first stage for developing a simultaneous method, nine eluents were compared for their efficiency to recover viruses from a 100 gm spiked biosolids sample. In the second stage, the three top performing eluents were thoroughly evaluated for the recovery of bacteria, viruses, and helminthes. For all three groups of pathogens, the glycine-based eluent provided higher recovery than the beef extract-based eluent. Additional experiments were performed to optimize performance of glycine-based eluent under various procedural factors such as, solids to eluent ratio, stir time, and centrifugation conditions. Last, the new method was directly compared with the EPA methods for the recovery of the three groups of pathogens spiked in duplicate samples of biosolids collected from different sources. For viruses, the new method yielded up to 10% higher recoveries than the EPA method. For bacteria and helminths, recoveries were 74% and 83% by the new method compared to 34% and 68% by the EPA method, respectively. The unified sample processing method significantly reduces the time required for processing biosolids samples for different groups of pathogens; it is less impacted by the intrinsic variability of samples, while providing higher yields (P = 0.05) and greater consistency than the current EPA methods.
Bhagchandani, Sharda P; Kubade, Sushant; Nikhare, Priyanka P; Manke, Sonali; Chandak, Nitin H; Kabra, Dinesh; Baheti, Neeraj N; Agrawal, Vijay S; Sarda, Pankaj; Mahajan, Parikshit; Ganjre, Ashish; Purohit, Hemant J; Singh, Lokendra; Taori, Girdhar M; Daginawala, Hatim F; Kashyap, Rajpal S
Bacterial meningitis is a dreadful infectious disease with a high mortality and morbidity if remained undiagnosed. Traditional diagnostic methods for bacterial meningitis pose a challenge in accurate identification of pathogen, making prognosis difficult. The present study is therefore aimed to design and evaluate a specific and sensitive nested 16S rDNA genus-based polymerase chain reaction (PCR) assay using clinical cerebrospinal fluid (CSF) for rapid diagnosis of eight pathogens causing the disease. The present work was dedicated to development of an in-house genus specific 16S rDNA nested PCR covering pathogens of eight genera responsible for causing bacterial meningitis using newly designed as well as literature based primers for respective genus. A total 150 suspected meningitis CSF obtained from the patients admitted to Central India Institute of Medical Sciences (CIIMS), India during the period from August 2011 to May 2014, were used to evaluate clinical sensitivity and clinical specificity of optimized PCR assays. The analytical sensitivity and specificity of our newly designed genus-specific 16S rDNA PCR were found to be ≥92%. With such a high sensitivity and specificity, our in-house nested PCR was able to give 100% sensitivity in clinically confirmed positive cases and 100% specificity in clinically confirmed negative cases indicating its applicability in clinical diagnosis. Our in-house nested PCR system therefore can diagnose the accurate pathogen causing bacterial meningitis and therefore be useful in selecting a specific treatment line to minimize morbidity. Results are obtained within 24 h and high sensitivity makes this nested PCR assay a rapid and accurate diagnostic tool compared to traditional culture-based methods.
Morales-Sánchez, M A; Domínguez-Gómez, M A; Jurado-Santa Cruz, F; Peralta-Pedrero, M L
Alopecia areata is an autoimmune inflammatory disease affecting the hair follicles. Researchers are currently interested in whether the presence of bacterial pathogens and/or a history of immunization can trigger an autoimmune response in patients who are genetically predisposed. This study aimed to determine whether there is an association between the development of alopecia areata and throat carriage of bacterial pathogens or a history of immunization. Sixty-five men and women with alopecia areata and 65 control patients with other skin diseases were studied at the Dr Ladislao de la Pascua Dermatology Clinic between September 2008 and February 2009. The patients ranged in age from 18-59 years. Patients with scalp diseases were excluded from the control group. In all cases, the patient was questioned about immunizations received in the previous 6 months, and a throat swab was cultured. A history of immunization (odds ratio [OR], 3.3; 95% confidence interval [CI], 1.6-6.7; P=.001), the presence of bacterial pathogens in the oropharynx (OR, 2.6; 95% CI, 1.1-6.2; P=.033), and being a carrier of Streptococcus pyogenes (OR, 2.1; 95% CI, 1.7-2.5; P=.042) were risk factors for alopecia areata. Klebsiella pneumoniae, S. pyogenes, Pseudomonas aeruginosa, Streptococcus pneumoniae, Serratia marcescens and Escherichia coli were isolated from cultures. This is the first study to show an association between alopecia areata and throat carriage of bacterial pathogens or history of immunization, as risk factors for development of the disease. Given the characteristics of our study population, the association appears valid for patients with less than 25% hair loss and a course of disease under 1 year.
Giaouris, Efstathios; Heir, Even; Desvaux, Mickaël; Hébraud, Michel; Møretrø, Trond; Langsrud, Solveig; Doulgeraki, Agapi; Nychas, George-John; Kačániová, Miroslava; Czaczyk, Katarzyna; Ölmez, Hülya; Simões, Manuel
A community-based sessile life style is the normal mode of growth and survival for many bacterial species. Under such conditions, cell-to-cell interactions are inevitable and ultimately lead to the establishment of dense, complex and highly structured biofilm populations encapsulated in a self-produced extracellular matrix and capable of coordinated and collective behavior. Remarkably, in food processing environments, a variety of different bacteria may attach to surfaces, survive, grow, and form biofilms. Salmonella enterica, Listeria monocytogenes, Escherichia coli, and Staphylococcus aureus are important bacterial pathogens commonly implicated in outbreaks of foodborne diseases, while all are known to be able to create biofilms on both abiotic and biotic surfaces. Particularly challenging is the attempt to understand the complexity of inter-bacterial interactions that can be encountered in such unwanted consortia, such as competitive and cooperative ones, together with their impact on the final outcome of these communities (e.g., maturation, physiology, antimicrobial resistance, virulence, dispersal). In this review, up-to-date data on both the intra- and inter-species interactions encountered in biofilms of these pathogens are presented. A better understanding of these interactions, both at molecular and biophysical levels, could lead to novel intervention strategies for controlling pathogenic biofilm formation in food processing environments and thus improve food safety. PMID:26347727
There are a number of significant diseases among cultured and free-ranging freshwater fishes that have a bacterial etiology; these represent a variety of gram-negative and gram-positive genera. Confirmatory diagnosis of these diseases involves primary isolation of the causative bacterium on bacteriologic media. Frequently used "general" bacteriologic media simply provide the essential nutrients for growth. For most of the major pathogens, however, there are differential and/or selective media that facilitate primary recovery. Some specialized media are available as "ready-to-use" from suppliers, while others must be prepared. Differential media employ various types of indicator systems, such as pH indicators, that allow diagnosticians to observe assimilation of selected substrates. An advantage to the use of differential media for primary isolation is that they hasten bacterial characterization by yielding the appropriate positive or negative result for a particular substrate, often leading to a presumptive identification. Selective media also incorporate agent(s) that inhibit the growth of contaminants typically encountered with samples from aquatic environments. Media that incorporate differential and/or selective components are ideally based on characters that are unique to the targeted bacterium, and their use can reduce the time associated with diagnosis and facilitate early intervention in affected fish populations. In this review, the concepts of general and differential/selective bacteriologic media and their use and development for fish pathogens are discussed. The media routinely employed for primary isolation of the significant bacterial pathogens of fishes are presented. ?? Wildlife Disease Association 2008.
Joseph, Baby; Dhas, Berlina; Hena, Vimalin; Raj, Justin
Objective To isolate and identify Bacillus subtilis (B. subtilis) from soil and to characterize and partially purify the bacteriocin. To evaluate the antimicrobial activity against four diabetic foot ulcer bacterial pathogens. Methods Genotypic identification was done based on Bergey's manual of systemic bacteriology. Antimicrobial susceptibility test was done by Kirby-Bauer disc diffusion method. Colonies were identified by colony morphology and biochemical characterization and also compared with MTCC 121 strain. Further identification was done by 16S rRNA sequencing. Inhibitory activities of partially purified bacteriocin on all the DFU isolates were done by agar well diffusion method. The strain was identified to produce bacteriocin by stab overlay assay. Bacteriocin was extracted by organic solvent extraction using chloroform, further purified by HPLC and physical, and chemical characterization was performed. Results The four isolates showed high level of resistance to amoxyclav and sensitivity to ciprofloxacin. HPLC purification revealed that the extracts are bacteriocin. The phylogenetic tree analysis results showed that the isolate was 99% related to B. subtilis BSF01. The results reveled activity to all the four isolates and high level of activity was seen in case of Klebsiella sp. Conclusions Partially purified bacteriocin was found to have antimicrobial activity against the four diabetic foot ulcer bacterial pathogens, which can thus be applied as a better drug molecule on further studies. The strain B. subtilis are found to be safe for use and these antimicrobial peptides can be used as an antimicrobial in humans to treat DFU bacterial pathogens. PMID:24093784
Jing-Zi, Piao; Zheng-Xin, He; Wei-Jun, Chen; Yong-Qiang, Jiang
Acute bacterial meningitis remains a life-threatening infectious disease with considerable morbidity and mortality. DNA-based detection methods are an urgent requisite for meningitis-causing bacterial pathogens for the prevention of outbreaks and control of infections. We proposed a novel PCR-mass spectrometry (PCR-Mass) assay for the simultaneous detection of four meningitis-causing agents, Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae, and Mycobacterium tuberculosis in the present study. A total of 138 cerebrospinal fluid (CSF) samples (including 56 CSF culture positive, 44 CSF culture negative, and 38 CSF control) were enrolled and analyzed by PCR/Mass. Results were compared to real-time PCR detection. These four targeting pathogens could be discriminated without cross-reaction by the accurate detection of the corresponding extension products with different masses. The limits of detection were 102 copies/reaction for S. pneumoniae, H. influenzae, and N. meningitidis and 103 for M. tuberculosis. The evaluation of the culture-positive CSF specimens from the meningitis patients provided an overall agreement rate of 85.7% with PCR-Mass and real-time PCR. The PCR-Mass was also able to detect the targeting pathogens from culture-negative CSF specimens from meningitis patients receiving early antibiotic treatment. PCR-Mass could be used for the molecular detection of bacterial meningitis and tuberculosis, especially when early antibiotic treatment has been administered to the suspected patients.
Joseph, Susan; Forsythe, Stephen J.
Cronobacter spp. (previously known as Enterobacter sakazakii) is a bacterial pathogen affecting all age groups, with particularly severe clinical complications in neonates and infants. One recognized route of infection being the consumption of contaminated infant formula. As a recently recognized bacterial pathogen of considerable importance and regulatory control, appropriate detection, and identification schemes are required. The application of multilocus sequence typing (MLST) and analysis (MLSA) of the seven alleles atpD, fusA, glnS, gltB, gyrB, infB, and ppsA (concatenated length 3036 base pairs) has led to considerable advances in our understanding of the genus. This approach is supported by both the reliability of DNA sequencing over subjective phenotyping and the establishment of a MLST database which has open access and is also curated; http://www.pubMLST.org/cronobacter. MLST has been used to describe the diversity of the newly recognized genus, instrumental in the formal recognition of new Cronobacter species (C. universalis and C. condimenti) and revealed the high clonality of strains and the association of clonal complex 4 with neonatal meningitis cases. Clearly the MLST approach has considerable benefits over the use of non-DNA sequence based methods of analysis for newly emergent bacterial pathogens. The application of MLST and MLSA has dramatically enabled us to better understand this opportunistic bacterium which can cause irreparable damage to a newborn baby’s brain, and has contributed to improved control measures to protect neonatal health. PMID:23189075
Setterington, Emma B.; Alocilja, Evangelyn C.
Biological defense and security applications demand rapid, sensitive detection of bacterial pathogens. This work presents a novel qualitative electrochemical detection technique which is applied to two representative bacterial pathogens, Bacillus cereus (as a surrogate for B. anthracis) and Escherichia coli O157:H7, resulting in detection limits of 40 CFU/mL and 6 CFU/mL, respectively, from pure culture. Cyclic voltammetry is combined with immunomagnetic separation in a rapid method requiring approximately 1 h for presumptive positive/negative results. An immunofunctionalized magnetic/polyaniline core/shell nano-particle (c/sNP) is employed to extract target cells from the sample solution and magnetically position them on a screen-printed carbon electrode (SPCE) sensor. The presence of target cells significantly inhibits current flow between the electrically active c/sNPs and SPCE. This method has the potential to be adapted for a wide variety of target organisms and sample matrices, and to become a fully portable system for routine monitoring or emergency detection of bacterial pathogens. PMID:25585629
Viršek, Manca Kovač; Lovšin, Marija Nika; Koren, Špela; Kržan, Andrej; Peterlin, Monika
Microplastics is widespread in the marine environment where it can cause numerous negative effects. It can provide space for the growth of organisms and serves as a vector for the long distance transfer of marine microorganisms. In this study, we examined the sea surface concentrations of microplastics in the North Adriatic and characterized bacterial communities living on the microplastics. DNA from microplastics particles was isolated by three different methods, followed by PCR amplification of 16S rDNA, clone libraries preparation and phylogenetic analysis. 28 bacterial species were identified on the microplastics particles including Aeromonas spp. and hydrocarbon-degrading bacterial species. Based on the 16S rDNA sequences the pathogenic fish bacteria Aeromonas salmonicida was identified for the first time on microplastics. Because A. salmonicida is responsible for illnesses in fish, it is crucial to get answers if and how microplastics pollution is responsible for spreading of diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.
Towle, Dana; Callan, Deborah A; Farrel, Patricia A; Egan, Marie E; Murray, Thomas S
Contaminated nebulizers are a potential source of bacterial infection but no single method is universally accepted for disinfection. We hypothesized that baby-bottle steam sterilizers effectively disinfect home nebulizers. Home nebulizers were inoculated with the common CF respiratory pathogens methicillin resistant Staphylococcus aureus, Burkholderia cepacia, Haemophilus influenzae, mucoid and non mucoid Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The nebulizers were swabbed for bacterial growth, treated with either the AVENT (Philips), the NUK Quick & Ready (Gerber) or DRY-POD (Camera Baby) baby bottle steam sterilizer and reswabbed for bacterial growth. All steam sterilizers were effective at disinfecting all home nebulizers. Viable bacteria were not recovered from any inoculated site after steam treatment, under any conditions tested. Steam treatment is an effective disinfection method. Additional studies are needed to confirm whether these results are applicable to the clinical setting. Copyright © 2012 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.
Gopal, Judy; Lee, Chia-Hsun; Wu, Hui-Fen
This study demonstrates the first use of matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) to trace the Invivo infection kinetics of the well known deadly pathogen Staphylococcus aureus in Swiss albino mice. The growth curve of the bacteria from the point of injection (200μL of bacterial suspension (10(8)cfu/mL)) into the mouse blood till mortality (death) was periodically analyzed using the plate counting method and MALDI-MS. Bacterial counts of 10(3)cfu/mL were observed in the log phase of the growth curve in the blood and 10(2)cfu/mL were observed in the urine samples. Death occurred in the log phase of the growth curve, where the bacterial counts showed steady increase. In other cases, the bacteria counts started decreasing after 48h and by 96h the bacteria got totally eliminated from the mouse and these mice survived. Direct MALDI-MS was not feasible for tracking the bacteria in the infected blood. However, ionic liquid 1-Butyl-3-methylimidazolium tetrafluoroborate was successful in enabling bacterial detection amidst the strong blood peaks. But, in the case of the urine analysis, it was observed that direct MALDI-MS was adequate to enable detection. The results obtained prove the efficacy of MALDI-MS for analyzing pathogenic bacteria in clinical samples. This article is part of a Special Issue entitled: Proteomics: The clinical link. Copyright © 2011 Elsevier B.V. All rights reserved.
Vogt, Stefanie L; Peña-Díaz, Jorge; Finlay, B Brett
Gastrointestinal pathogens must overcome many obstacles in order to successfully colonize a host, not the least of which is the presence of the gut microbiota, the trillions of commensal microorganisms inhabiting mammals' digestive tracts, and their products. It is well established that a healthy gut microbiota provides its host with protection from numerous pathogens, including Salmonella species, Clostridium difficile, diarrheagenic Escherichia coli, and Vibrio cholerae. Conversely, pathogenic bacteria have evolved mechanisms to establish an infection and thrive in the face of fierce competition from the microbiota for space and nutrients. Here, we review the evidence that gut microbiota-generated metabolites play a key role in determining the outcome of infection by bacterial pathogens. By consuming and transforming dietary and host-produced metabolites, as well as secreting primary and secondary metabolites of their own, the microbiota define the chemical environment of the gut and often determine specific host responses. Although most gut microbiota-produced metabolites are currently uncharacterized, several well-studied molecules made or modified by the microbiota are known to affect the growth and virulence of pathogens, including short-chain fatty acids, succinate, mucin O-glycans, molecular hydrogen, secondary bile acids, and the AI-2 quorum sensing autoinducer. We also discuss challenges and possible approaches to further study of the chemical interplay between microbiota and gastrointestinal pathogens. Copyright © 2015 Elsevier Ltd. All rights reserved.
Daszak, Peter; Kilpatrick, A. Marm; Burke, Donald S.
Understanding the emergence of new zoonotic agents requires knowledge of pathogen biodiversity in wildlife, human-wildlife interactions, anthropogenic pressures on wildlife populations, and changes in society and human behavior. We discuss an interdisciplinary approach combining virology, wildlife biology, disease ecology, and anthropology that enables better understanding of how deforestation and associated hunting leads to the emergence of novel zoonotic pathogens. PMID:16485465
Schwab, Clarissa; Cristescu, Bogdan; Northrup, Joseph M; Stenhouse, Gordon B; Gänzle, Michael
Diet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic clostridia in wild and captive grizzly bears (Ursus arctos) and relates these to food resources consumed by bears. Feces were obtained from animals of two wild populations and from two captive animals during an active bear season. Wild animals consumed a diverse diet composed of plant material, animal prey and insects. Captive animals were fed a regular granulated diet with a supplement of fruits and vegetables. Bacterial populations were analyzed using quantitative PCR. Fecal microbiota composition fluctuated in wild and in captive animals. The abundance of Clostridium clusters I and XI, and of C. perfringens correlated to regular diet protein intake. Enteroaggregative E. coli were consistently present in all populations. The C. sordellii phospholipase C was identified in three samples of wild animals and for the first time in Ursids. This is the first longitudinal study monitoring the fecal microbiota of wild carnivores and comparing it to that of captive individuals of the same species. Location and diet affected fecal bacterial populations as well as the presence of enteric pathogens.
Schwab, Clarissa; Cristescu, Bogdan; Northrup, Joseph M.; Stenhouse, Gordon B.; Gänzle, Michael
Background Diet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic clostridia in wild and captive grizzly bears (Ursus arctos) and relates these to food resources consumed by bears. Methodology/Principal Findings Feces were obtained from animals of two wild populations and from two captive animals during an active bear season. Wild animals consumed a diverse diet composed of plant material, animal prey and insects. Captive animals were fed a regular granulated diet with a supplement of fruits and vegetables. Bacterial populations were analyzed using quantitative PCR. Fecal microbiota composition fluctuated in wild and in captive animals. The abundance of Clostridium clusters I and XI, and of C. perfringens correlated to regular diet protein intake. Enteroaggregative E. coli were consistently present in all populations. The C. sordellii phospholipase C was identified in three samples of wild animals and for the first time in Ursids. Conclusion This is the first longitudinal study monitoring the fecal microbiota of wild carnivores and comparing it to that of captive individuals of the same species. Location and diet affected fecal bacterial populations as well as the presence of enteric pathogens. PMID:22194798
Escobedo-Hinojosa, Wendy; Pardo-López, Liliana
Little is known about the diversity of bacteria in the Southwestern Gulf of Mexico. The aim of the study illustrated in this perspective was to search for the presence of bacterial pathogens in this ecosystem, using metagenomic data recently generated by the Mexican research group known as the Gulf of Mexico Research Consortium. Several genera of bacteria annotated as pathogens were detected in water and sediment marine samples. As expected, native and ubiquitous pathogenic bacteria genera such as Burkolderia, Halomonas, Pseudomonas, Shewanella and Vibrio were highly represented. Surprisingly, non-native genera of public health concern were also detected, including Borrelia, Ehrlichia, Leptospira, Mycobacterium, Mycoplasma, Salmonella, Staphylococcus, Streptococcus and Treponema. While there are no previous metagenomics studies of this environment, the potential influences of natural, anthropogenic and ecological factors on the diversity of putative pathogenic bacteria found in it are reviewed. The taxonomic annotation herein reported provides a starting point for an improved understanding of bacterial biodiversity in the Southwestern Gulf of Mexico. It also represents a useful tool in public health as it may help identify infectious diseases associated with exposure to marine water and ingestion of fish or shellfish, and thus may be useful in predicting and preventing waterborne disease outbreaks. © FEMS 2017. All rights reserved. For permissions, please e-mail: email@example.com.
Czyż, Daniel M.; Potluri, Lakshmi-Prasad; Jain-Gupta, Neeta; Riley, Sean P.; Martinez, Juan J.; Steck, Theodore L.; Crosson, Sean; Gabay, Joëlle E.
ABSTRACT We sought a new approach to treating infections by intracellular bacteria, namely, by altering host cell functions that support their growth. We screened a library of 640 Food and Drug Administration (FDA)-approved compounds for agents that render THP-1 cells resistant to infection by four intracellular pathogens. We identified numerous drugs that are not antibiotics but were highly effective in inhibiting intracellular bacterial growth with limited toxicity to host cells. These compounds are likely to target three kinds of host functions: (i) G protein-coupled receptors, (ii) intracellular calcium signals, and (iii) membrane cholesterol distribution. The compounds that targeted G protein receptor signaling and calcium fluxes broadly inhibited Coxiella burnetii, Legionella pneumophila, Brucella abortus, and Rickettsia conorii, while those directed against cholesterol traffic strongly attenuated the intracellular growth of C. burnetii and L. pneumophila. These pathways probably support intracellular pathogen growth so that drugs that perturb them may be therapeutic candidates. Combining host- and pathogen-directed treatments is a strategy to decrease the emergence of drug-resistant intracellular bacterial pathogens. PMID:25073644
van Spijk, J N; Schmitt, S; Fürst, A E; Schoster, A
Antimicrobial resistance has become an important concern in veterinary medicine. The aim of this study was to describe the rate of antimicrobial resistance in common equine pathogens and to determine the occurrence of multidrug-resistant isolates. A retrospective analysis of all susceptibility testing results from bacterial pathogens cultured from horses at the University of Zurich Equine Hospital (2012-2015) was performed. Strains exhibiting resistance to 3 or more antimicrobial categories were defined as multidrug-resistant. Susceptibility results from 303 bacterial pathogens were analyzed, most commonly Escherichia coli (60/303, 20%) and Staphylococcus aureus (40/303, 13%). High rates of acquired resistance against commonly used antimicrobials were found in most of the frequently isolated equine pathogens. The highest rate of multidrug resistance was found in isolates of Acinetobacter baumannii (23/24, 96%), followed by Enterobacter cloacae complex (24/28, 86%) and Escherichia coli (48/60, 80%). Overall, 60% of Escherichia coli isolates were phenotypically ESBL-producing and 68% of Staphylococcus spp. were phenotypically methicillin-resistant. High rates of acquired antimicrobial resistance towards commonly used antibiotics are concerning and underline the importance of individual bacteriological and antimicrobial susceptibility testing to guide antimicrobial therapy. Minimizing and optimizing antimicrobial therapy in horses is needed.
Fichi, G; Cardeti, G; Cersini, A; Mancusi, C; Guarducci, M; Di Guardo, G; Terracciano, G
During 2014, six loggerhead turtles, Caretta caretta and one green turtle, Chelonia mydas, found stranded on the Tuscany coast of Italy, were examined for the presence of specific bacterial and viral agents, along with their role as carriers of fish and human pathogens. Thirteen different species of bacteria, 10 Gram negative and 3 Gram positive, were identified. Among them, two strains of Vibrio parahaemolyticus and one strain of Lactococcus garviae were recovered and confirmed by specific PCR protocols. No trh and tdh genes were detected in V. parahaemolyticus. The first isolation of L. garviae and the first detection of Betanodavirus in sea turtles indicate the possibility for sea turtles to act as carriers of fish pathogens. Furthermore, the isolation of two strains of V. parahaemolyticus highlights the possible role of these animals in human pathogens' diffusion. Copyright © 2016 Elsevier B.V. All rights reserved.
Rasool, Muhammad H; Siddique, Abu B; Saqalein, Muhammad; Asghar, Muhammad J; Zahoor, Muhammad A; Aslam, Bilal; Shafiq, Humerah B; Nisar, Muhammad A
To determine the occurrence of bacterial pathogens responsible for diarrhea and to engender information regarding the effectiveness of commonly used antibiotic against diarrhea. This cross-sectional study was conducted between April and July 2014. Samples were collected from the Divisional Headquarter and Allied Hospital, Faisalabad, Pakistan. The differential and selective media were used to isolate bacterial pathogens, which were identified through cultural characteristics, microscopy, and biochemical tests. Disc diffusion assay was carried out using Muller Hinton agar medium, and minimum inhibitory concentration was determined using broth dilution method against isolated pathogens. One hundred and forty-one (100%) samples were positive for some bacteria. Frequency of occurrence was Bacillus cereus (B. cereus) (66%), Escherichia coli (E.coli) (48.5%), Salmonella typhi (S. Typhi) (27.7%), Pseudomonas aeruginosa (P. aeruginosa) (8.5%), and Staphylococcus aureus (S. aureus) (4.3%). Single pathogen was detected in 20 (14.2%) samples whereas combinations were found in 121 (85.8%) samples. Bacillus cereus and E.coli were the most frequently detected pathogens followed by the S. Typhi, P. aeruginosa, and Staph. aureus. The percentage occurrence of isolated pathogens was 31% in B. cereus, 31% in E. coli, 18% in S. Typhi, 5% in P. aeruginosa, and 3% in Staph. aureus. Pseudomonas aeruginosa showed resistance against Amoxicillin and Cefotaxime, whereas S. aureus was found resistant against Cefotaxime. Statistical analysis using one way Analysis of Variance revealed that Ofloxacin and Gentamicin had significant (p less than 0.05) differences against all isolates as compared with other antibiotics used in this study.
Lu, Yun-Yun; Luo, Rong; Fu, Zhou
To investigate the distribution of pathogens and bacterial resistance in children with severe community-acquired pneumonia (CAP). A total of 522 children with severe CAP who were hospitalized in 2016 were enrolled as study subjects. According to their age, they were divided into infant group (402 infants aged 28 days to 1 year), young children group (73 children aged 1 to 3 years), preschool children group (35 children aged 3 to 6 years), and school-aged children group (12 children aged ≥6 years). According to the onset season, all children were divided into spring group (March to May, 120 children), summer group (June to August, 93 children), autumn group (September to November, 105 children), and winter group (December to February, 204 children). Sputum specimens from the deep airway were collected from all patients. The phoenix-100 automatic bacterial identification system was used for bacterial identification and drug sensitivity test. The direct immunofluorescence assay was used to detect seven common respiratory viruses. The quantitative real-time PCR was used to detect Mycoplasma pneumoniae (MP) and Chlamydia trachomatis (CT). Of all the 522 children with severe CAP, 419 (80.3%) were found to have pathogens, among whom 190 (45.3%) had mixed infection. A total of 681 strains of pathogens were identified, including 371 bacterial strains (54.5%), 259 viral strains (38.0%), 12 fungal strains (1.8%), 15 MP strains (2.2%), and 24 CT strains (3.5%). There were significant differences in the distribution of bacterial, viral, MP, and fungal infections between different age groups (P<0.05). There were significant differences in the incidence rate of viral infection between different season groups (P<0.05), with the highest incidence rate in winter. The drug-resistance rates of Streptococcus pneumoniae to erythromycin, tetracycline, and clindamycin reached above 85%, and the drug-resistance rates of Staphylococcus aureus to penicillin, erythromycin, and clindamycin
Wittebole, Xavier; De Roock, Sophie; Opal, Steven M
The seemingly inexorable spread of antibiotic resistance genes among microbial pathogens now threatens the long-term viability of our current antimicrobial therapy to treat severe bacterial infections such as sepsis. Antibiotic resistance is reaching a crisis situation in some bacterial pathogens where few therapeutic alternatives remain and pan-resistant strains are becoming more prevalent. Non-antibiotic therapies to treat bacterial infections are now under serious consideration and one possible option is the therapeutic use of specific phage particles that target bacterial pathogens. Bacteriophage therapy has essentially been re-discovered by modern medicine after widespread use of phage therapy in the pre-antibiotic era lost favor, at least in Western countries, after the introduction of antibiotics. We review the current therapeutic rationale and clinical experience with phage therapy as a treatment for invasive bacterial infection as novel alternative to antimicrobial chemotherapy. PMID:23973944
Matsunaga, James; Barocchi, Michele A.; Croda, Julio; Young, Tracy A.; Sanchez, Yolanda; Siqueira, Isadora; Bolin, Carole A.; Reis, Mitermayer G.; Riley, Lee W.; Haake, David A.; Ko, Albert I.
Summary Proteins with bacterial immunoglobulin-like (Big) domains, such as the Yersinia pseudotuberculosis invasin and Escherichia coli intimin, are surface-expressed proteins that mediate host mammalian cell invasion or attachment. Here, we report the identification and characterization of a new family of Big domain proteins, referred to as Lig (leptospiral Ig-like) proteins, in pathogenic Leptospira. Screening of L. interrogans and L. kirschneri expression libraries with sera from leptospirosis patients identified 13 lambda phage clones that encode tandem repeats of the 90 amino acid Big domain. Two lig genes, designated ligA and ligB, and one pseudo-gene, ligC, were identified. The ligA and ligB genes encode amino-terminal lipoprotein signal peptides followed by 10 or 11 Big domain repeats and, in the case of ligB, a unique carboxy-terminal non-repeat domain. The organization of ligC is similar to that of ligB but contains mutations that disrupt the reading frame. The lig sequences are present in pathogenic but not saprophytic Leptospira species. LigA and LigB are expressed by a variety of virulent leptospiral strains. Loss of Lig protein and RNA transcript expression is correlated with the observed loss of virulence during culture attenuation of pathogenic strains. High-pressure freeze substitution followed by immunocytochemical electron microscopy confirmed that the Lig proteins were localized to the bacterial surface. Immunoblot studies with patient sera found that the Lig proteins are a major antigen recognized during the acute host infection. These observations demonstrate that the Lig proteins are a newly identified surface protein of pathogenic Leptospira, which by analogy to other bacterial immunoglobulin superfamily virulence factors, may play a role in host cell attachment and invasion during leptospiral pathogenesis. PMID:12890019
Matsunaga, James; Barocchi, Michele A; Croda, Julio; Young, Tracy A; Sanchez, Yolanda; Siqueira, Isadora; Bolin, Carole A; Reis, Mitermayer G; Riley, Lee W; Haake, David A; Ko, Albert I
Proteins with bacterial immunoglobulin-like (Big) domains, such as the Yersinia pseudotuberculosis invasin and Escherichia coli intimin, are surface-expressed proteins that mediate host mammalian cell invasion or attachment. Here, we report the identification and characterization of a new family of Big domain proteins, referred to as Lig (leptospiral Ig-like) proteins, in pathogenic Leptospira. Screening of L. interrogans and L. kirschneri expression libraries with sera from leptospirosis patients identified 13 lambda phage clones that encode tandem repeats of the 90 amino acid Big domain. Two lig genes, designated ligA and ligB, and one pseudogene, ligC, were identified. The ligA and ligB genes encode amino-terminal lipoprotein signal peptides followed by 10 or 11 Big domain repeats and, in the case of ligB, a unique carboxy-terminal non-repeat domain. The organization of ligC is similar to that of ligB but contains mutations that disrupt the reading frame. The lig sequences are present in pathogenic but not saprophytic Leptospira species. LigA and LigB are expressed by a variety of virulent leptospiral strains. Loss of Lig protein and RNA transcript expression is correlated with the observed loss of virulence during culture attenuation of pathogenic strains. High-pressure freeze substitution followed by immunocytochemical electron microscopy confirmed that the Lig proteins were localized to the bacterial surface. Immunoblot studies with patient sera found that the Lig proteins are a major antigen recognized during the acute host infection. These observations demonstrate that the Lig proteins are a newly identified surface protein of pathogenic Leptospira, which by analogy to other bacterial immunoglobulin superfamily virulence factors, may play a role in host cell attachment and invasion during leptospiral pathogenesis.
Srinivasan, Usha; Ponnaluri, Sreelatha; Villareal, Lisa; Gillespie, Brenda; Wen, Ai; Miles, Arianna; Bucholz, Brigette; Marrs, Carl F.; Iyer, Ram K.; Misra, Dawn; Foxman, Betsy
We demonstrate the feasibility of using qPCR on DNA extracted from vaginal Gram stain slides to estimate the presence and relative abundance of specific bacterial pathogens. We first tested Gram stained slides spiked with a mix of 108 cfu/ml of Escherichia coli and 105 cfu/ml of Lactobacillus acidophilus. Primers were designed for amplification of total and species-specific bacterial DNA based on 16S ribosomal gene regions. Sample DNA was pre-amplified with nearly full length 16S rDNA ribosomal gene fragment, followed by quantitative PCR with genera and species-specific 16S rDNA primers. Pre-amplification PCR increased the bacterial amounts; relative proportions of Escherichia coli and Lactobacillus recovered from spiked slides remained unchanged. We applied this method to forty two archived Gram stained slides available from a clinical trial of cerclage in pregnant women at high risk of preterm birth. We found a high correlation between Nugent scores based on bacterial morphology of Lactobacillus, Gardenerella and Mobiluncus and amounts of quantitative PCR estimated genus specific DNA (rrn copies) from Gram stained slides. Testing of a convenience sample of eight paired vaginal swabs and Gram stains freshly collected from healthy women found similar qPCR generated estimates of Lactobacillus proportions from Gram stained slides and vaginal swabs. Archived Gram stained slides collected from large scale epidemiologic and clinical studies represent a valuable, untapped resource for research on the composition of bacterial communities that colonize human mucosal surfaces. PMID:23071487
Shestov, Maksim; Ontañón, Santiago; Tozeren, Aydin
Bacterial infections comprise a global health challenge as the incidences of antibiotic resistance increase. Pathogenic potential of bacteria has been shown to be context dependent, varying in response to environment and even within the strains of the same genus. We used the KEGG repository and extensive literature searches to identify among the 2527 bacterial genomes in the literature those implicated as pathogenic to the host, including those which show pathogenicity in a context dependent manner. Using data on the gene contents of these genomes, we identified sets of genes highly abundant in pathogenic but relatively absent in commensal strains and vice versa. In addition, we carried out genome comparison within a genus for the seventeen largest genera in our genome collection. We projected the resultant lists of ortholog genes onto KEGG bacterial pathways to identify clusters and circuits, which can be linked to either pathogenicity or synergy. Gene circuits relatively abundant in nonpathogenic bacteria often mediated biosynthesis of antibiotics. Other synergy-linked circuits reduced drug-induced toxicity. Pathogen-abundant gene circuits included modules in one-carbon folate, two-component system, type-3 secretion system, and peptidoglycan biosynthesis. Antibiotics-resistant bacterial strains possessed genes modulating phagocytosis, vesicle trafficking, cytoskeletal reorganization, and regulation of the inflammatory response. Our study also identified bacterial genera containing a circuit, elements of which were previously linked to Alzheimer's disease. Present study produces for the first time, a signature, in the form of a robust list of gene circuitry whose presence or absence could potentially define the pathogenicity of a microbiome. Extensive literature search substantiated a bulk majority of the commensal and pathogenic circuitry in our predicted list. Scanning microbiome libraries for these circuitry motifs will provide further insights into the complex
Law, Jodi Woan-Fei; Ab Mutalib, Nurul-Syakima; Chan, Kok-Gan; Lee, Learn-Han
The incidence of foodborne diseases has increased over the years and resulted in major public health problem globally. Foodborne pathogens can be found in various foods and it is important to detect foodborne pathogens to provide safe food supply and to prevent foodborne diseases. The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR), multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP) and oligonucleotide DNA microarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases. PMID:25628612
Harjanti, D. W.; Ciptaningtyas, R.; Wahyono, F.; Setiatin, ET
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.
Jung, Hwa Sik; Kang, Byung Ju; Ra, Seung Won; Seo, Kwang Won; Jegal, Yangjin; Jun, Jae Bum; Jung, Jiwon; Jeong, Joseph; Jeon, Hee Jeong; Ahn, Jae Sung; Lee, Taehoon; Ahn, Jong Joon
Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ≥16 years, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia. Copyright©2017. The Korean Academy of Tuberculosis and Respiratory Diseases
Jung, Hwa Sik; Kang, Byung Ju; Ra, Seung Won; Seo, Kwang Won; Jegal, Yangjin; Jun, Jae-Bum; Jung, Jiwon; Jeong, Joseph; Jeon, Hee-Jeong; Ahn, Jae-Sung
Background Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. Methods Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. Results A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ≥16 years, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. Conclusion The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia. PMID:28905531
Naguib, Mahmoud M; Ulrich, Reiner; Kasbohm, Elisa; Eng, Christine L P; Hoffmann, Donata; Grund, Christian; Beer, Martin; Harder, Timm C
The cocirculation of zoonotic highly pathogenic avian influenza virus (HPAIV) of subtype H5N1 and avian influenza virus (AIV) of subtype H9N2 among poultry in Egypt for at least 6 years should render that country a hypothetical hot spot for the emergence of reassortant, phenotypically altered viruses, yet no reassortants have been detected in Egypt. The present investigations proved that reassortants of the Egyptian H5N1 clade 184.108.40.206 virus and H9N2 virus of the G1-B lineage can be generated by coamplification in embryonated chicken eggs. Reassortants were restricted to the H5N1 subtype and acquired between two and all six of the internal segments of the H9N2 virus. Five selected plaque-purified reassortant clones expressed a broad phenotypic spectrum both in vitro and in vivo Two groups of reassortants were characterized to have retarded growth characteristics in vitro compared to the H5N1 parent virus. One clone provoked reduced mortality in inoculated chickens, although the characteristics of a highly pathogenic phenotype were retained. Enhanced zoonotic properties were not predicted for any of these clones, and this prediction was confirmed by ferret inoculation experiments: neither the H5N1 parent virus nor two selected clones induced severe clinical symptoms or were transmitted to sentinel ferrets by contact. While the emergence of reassortants of Egyptian HPAIV of subtype H5N1 with internal gene segments of cocirculating H9N2 viruses is possible in principle, the spread of such viruses is expected to be governed by their fitness to outcompete the parental viruses in the field. The eventual spread of attenuated phenotypes, however, would negatively impact syndrome surveillance on poultry farms and might foster enzootic virus circulation. IMPORTANCE Despite almost 6 years of the continuous cocirculation of highly pathogenic avian influenza virus H5N1 and avian influenza virus H9N2 in poultry in Egypt, no reassortants of the two subtypes have been reported
Naguib, Mahmoud M.; Ulrich, Reiner; Kasbohm, Elisa; Eng, Christine L. P.; Hoffmann, Donata; Grund, Christian; Beer, Martin
ABSTRACT The cocirculation of zoonotic highly pathogenic avian influenza virus (HPAIV) of subtype H5N1 and avian influenza virus (AIV) of subtype H9N2 among poultry in Egypt for at least 6 years should render that country a hypothetical hot spot for the emergence of reassortant, phenotypically altered viruses, yet no reassortants have been detected in Egypt. The present investigations proved that reassortants of the Egyptian H5N1 clade 220.127.116.11 virus and H9N2 virus of the G1-B lineage can be generated by coamplification in embryonated chicken eggs. Reassortants were restricted to the H5N1 subtype and acquired between two and all six of the internal segments of the H9N2 virus. Five selected plaque-purified reassortant clones expressed a broad phenotypic spectrum both in vitro and in vivo. Two groups of reassortants were characterized to have retarded growth characteristics in vitro compared to the H5N1 parent virus. One clone provoked reduced mortality in inoculated chickens, although the characteristics of a highly pathogenic phenotype were retained. Enhanced zoonotic properties were not predicted for any of these clones, and this prediction was confirmed by ferret inoculation experiments: neither the H5N1 parent virus nor two selected clones induced severe clinical symptoms or were transmitted to sentinel ferrets by contact. While the emergence of reassortants of Egyptian HPAIV of subtype H5N1 with internal gene segments of cocirculating H9N2 viruses is possible in principle, the spread of such viruses is expected to be governed by their fitness to outcompete the parental viruses in the field. The eventual spread of attenuated phenotypes, however, would negatively impact syndrome surveillance on poultry farms and might foster enzootic virus circulation. IMPORTANCE Despite almost 6 years of the continuous cocirculation of highly pathogenic avian influenza virus H5N1 and avian influenza virus H9N2 in poultry in Egypt, no reassortants of the two subtypes have been
Ahiwale, Sangeeta; Tagunde, Sujata; Khopkar, Sushama; Karni, Mrudula; Gajbhiye, Milind; Kapadnis, Balasaheb
Water resources are contaminated by life-threatening multidrug resistant pathogenic bacteria. Unfortunately, these pathogenic bacteria do not respond to the traditional water purification methods. Therefore, there is a need of environmentally friendly strategies to overcome the problems associated with the antimicrobial resistant bacterial pathogens. In the present study, highly potent lytic phages against multidrug-resistant Salmonella enterica serovar Paratyphi B, Pseudomonas aeruginosa and Klebsiella pneumoniae were isolated from the Pavana river water. They belonged to the Podoviridae and Siphoviridae families. These phages were purified and enriched in the laboratory. Monovalent formulations of phiSPB, BVPaP-3 and KPP phages were prepared in three different liquids viz., phage broth, saline and distilled water. The phages were stable for almost 8-10 months in the phage broth at 4 degrees C. The stability of the phages in saline and distilled water was 5-6 months at 4 degrees C. All of the phages were stable only for 4-6 months in the phage broth at 30 degrees C. The monovalent phage formulation of psiSPB was applied at MOI < 1, as disinfectant against an exponential and stationary phase cells of Salmonella enterica serovar Paratyphi B in various water microcosms. The results indicated that there was almost 80 % reduction in the log phase cells of Salmonella serovar Paratyphi B in 24 h. In stationary phase cells, the reduction was comparatively less within same period. At the same time, there was concomitant increase in the phage population by 80% in all the microcosms indicating that psiSPB phage is highly potent in killing pathogen in water. Results strongly support that the formulation of psiSPB in the phage broth in monovalent form could be used as an effective biological disinfectant for preventing transmission of water-borne bacterial pathogens, including antimicrobial resistant ones.
Prithika, Udayakumar; Vikneswari, Ramaraj; Balamurugan, Krishnaswamy
One of the key issues pertaining to the control of memory is to respond to a consistently changing environment or microbial niche present in it. Human cyclic AMP response element binding protein (CREB) transcription factor which plays a crucial role in memory has a homolog in C. elegans, crh-1. crh-1 appears to influence memory processes to certain extent by habituation of the host to a particular environment. The discrimination between the pathogen and a non-pathogen is essential for C. elegans in a microbial niche which determines its survival. Training the nematodes in the presence of a virulent pathogen (S. aureus) and an opportunistic pathogen (P. mirabilis) separately exhibits a different behavioural paradigm. This appears to be dependent on the CREB transcription factor. Here we show that C. elegans homolog crh-1 helps in memory response for a short term against the interacting pathogens. Following conditioning of the nematodes to S. aureus and P. mirabilis, the wild type nematodes exhibited a positive response towards the respective pathogens which diminished slowly after 2h. By contrast, the crh-1 deficient nematodes had a defective memory post conditioning. The molecular data reinforces the importance of crh-1 gene in retaining the memory of nematode. Our results also suggest that involvement of neurotransmitters play a crucial role in modulating the memory of the nematode with the assistance of CREB. Therefore, we elucidate that CREB is responsible for the short term memory response in C. elegans against bacterial pathogens. Copyright © 2016 Elsevier GmbH. All rights reserved.
Yamahara, Kevan M.; Sassoubre, Lauren M.; Goodwin, Kelly D.
This report documents the presence of fecal indicators and bacterial pathogens in sand at 53 California marine beaches using both culture-dependent and -independent (PCR and quantitative PCR [QPCR]) methods. Fecal indicator bacteria were widespread in California beach sand, with Escherichia coli and enterococci detected at 68% and 94% of the beaches surveyed, respectively. Somatic coliphages and a Bacteroidales human-specific fecal marker were detected at 43% and 13% of the beaches, respectively. Dry sand samples from almost 30% of the beaches contained at least one of the following pathogens: Salmonella spp., Campylobacter spp., Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA), which were detected at 15%, 13%, 14%, and 3% of tested beaches, respectively. Fecal indicators and pathogens were poorly correlated to one another and to land cover. Sands were dry at the time of collection, and those with relatively high moisture tended to have higher concentrations or a more frequent occurrence of both indicators and pathogens. Using culture-dependent assays, fecal indicators decayed faster than pathogens in microcosm experiments using unaltered beach sand seeded with sewage and assessed by culture-dependent assays. The following order of persistence was observed (listed from most to least persistent): Campylobacter > Salmonella > somatic coliphages > enterococci > E. coli > F+ phages. In contrast, pathogens decayed faster than fecal indicators in culture-independent assays: enterococci > Bacteroidales human-specific marker > Salmonella > Campylobacter. Microcosm experiments demonstrated that both indicators and pathogens were mobilized by wetting with seawater. Decay rates measured by QPCR were lower than those measured with culture-dependent methods. Enterococcal persistence and possible growth were observed for wetted microcosms relative to unwetted controls. PMID:22247142
Burgess, Catherine M.; Rivas, Lucia; McDonnell, Mary J.; Duffy, Geraldine
Bacterial foodborne zoonotic diseases are of major concern, impacting public health and causing economic losses for the agricultural-food sector and the wider society. In the United States (US) alone foodborne illness from pathogens is responsible for 76 million cases of illnesses each year (Mead et al., 1999). Salmonella, Campylobacter jejuni and Enterohaemorraghic Escherichia coli (EHEC; predominately serotype O157:H7) and Listeria monocytogenes are the most predominant foodborne bacterial pathogens reported in the developed world (United States Department of Agriculture, 2001). The importance of meat and meat products as a vehicle of foodborne zoonotic pathogens cannot be underestimated (Center for Disease Control, 2006; Gillespie, O’Brien, Adak, Cheasty, & Willshaw, 2005; Mazick, Ethelberg, Nielsen, Molbak, & Lisby, 2006; Mead et al., 2006).
Vázquez-Torres, Andrés; Bäumler, Andreas
The electrochemical gradient that ensues from the enzymatic activity of cytochromes such as nitrate reductase, nitric oxide reductase, and quinol oxidase contributes to the bioenergetics of the bacterial cell. Reduction of nitrogen oxides by bacterial pathogens can, however, be uncoupled from proton translocation and biosynthesis of ATP or NH4+, but still linked to quinol and NADH oxidation. Ancestral nitric oxide reductases, as well as cytochrome coxidases and quinol bo oxidases evolved from the former, are capable of binding and detoxifying nitric oxide to nitrous oxide. The NO-metabolizing activity associated with these cytochromes can be a sizable source of antinitrosative defense in bacteria during their associations with host cells. Nitrosylation of terminal cytochromes arrests respiration, reprograms bacterial metabolism, stimulates antioxidant defenses and alters antibiotic cytotoxicity. Collectively, the bioenergetics and regulation of redox homeostasis that accompanies the utilization of nitrogen oxides and detoxification of nitric oxide by cytochromes of the electron transport chain increases fitness of many Gram-positive and –negative pathogens during their associations with invertebrate and vertebrate hosts. PMID:26426528
Uysal, B.; Bastas, K. K.
This study was focused on the role of antioxidant enzymes and total protein in imparting resistance against common bacterial blight caused by Xanthomonas axonopodis pv. phaseoli (Xap) and halo blight caused by Pseudomonas syringae pv. phaseolicola (Psp) in bean. Activities of Ascorbate peroxidase (APX), Catalase (CAT) and total protein were studied in resistant and susceptible bean genotypes. Five-day-old seedlings were inoculated with a bacterial suspension (108 CFU ml-1) and harvested at different time intervals (0, 12, 24 and 36 up to 72 h) under controlled growing conditions and assayed for antioxidant enzymes and total protein. Temporal increase of CAT, APX enzymes activities showed maximum activity at 12 h after both pathogens inoculation (hpi) in resistant cultivar, whereas in susceptible it increased at 72 h after both pathogens inoculation for CAT and 12, 24 h for APX enzymes. Maximum total protein activities were observed at 12 h and 24 h respectively after Xap, Psp inoculation (hpi) in resistant and maximum activities were observed at 24 h and 72 h respectively after Xap, Psp inoculation (hpi) in susceptible. Increase of antioxidant enzyme and total protein activities might be an important component in the defense strategy of resistance and susceptible bean genotypes against the bacterial infection. These findings suggest that disease protection is proportional to the amount of enhanced CAT, APX enzyme and total protein activity.
Despite the advent of next-generation sequencing (NGS) technologies, sophisticated data analysis and drug development efforts, bacterial drug resistance persists and is escalating in magnitude. To better control the pathogens, a thorough understanding of their genomic architecture and dynamics is vital. Bacterial genome is extremely complex, a mosaic of numerous co-operating and antagonizing components, altruistic and self-interested entities, behavior of which are predictable and conserved to some extent, yet largely dictated by an array of variables. In this regard, mobile genetic elements (MGE), DNA repair systems, post-segregation killing systems, toxin-antitoxin (TA) systems, restriction-modification (RM) systems etc. are dominant agents and horizontal gene transfer (HGT), gene redundancy, epigenetics, phase and antigenic variation etc. processes shape the genome. By illegitimate recombinations, deletions, insertions, duplications, amplifications, inversions, conversions, translocations, modification of intergenic regions and other alterations, bacterial genome is modified to tackle stressors like drugs, and host immune effectors. Over the years, thousands of studies have investigated this aspect and mammoth amount of insights have been accumulated. This review strives to distillate the existing information, formulate hypotheses and to suggest directions, that might contribute towards improved mitigation of the vicious pathogens. Copyright Â© 2016 Elsevier B.V. All rights reserved.
Towle, Dana; Baker, Vanisha; Schramm, Craig; O'Brien, Matthew; Collins, Melanie S; Feinn, Richard; Murray, Thomas S
The Cystic Fibrosis Foundation (CFF) recommends routine nebulizer disinfection for patients but compliance is challenging due to the heavy burden of home care. SoClean® is a user friendly ozone based home disinfection device currently for home respiratory equipment. The objective of this study was to determine whether SoClean® has potential as a disinfection device for families with CF by killing CF associated bacteria without altering nebulizer output. Ozone based disinfection effectively kills bacterial pathogens inoculated to home nebulizer equipment without gross changes in nebulizer function. Common bacterial pathogens associated with CF were inoculated onto the PariLC® jet nebulizer and bacterial recovery compared with or without varied ozone exposure. In separate experiments, nebulizer output was estimated after repeated ozone exposure by weighing the nebulizer. Ozone disinfection was time dependent with a 5 min infusion time and 120 min dwell time effectively killing >99.99% bacteria tested including Pseudomonas aeruginosa and Staphylococcus aureus. Over 250 h of repeat ozone exposure did not alter nebulizer output. This suggests SoClean® has potential as a user-friendly disinfection technique for home respiratory equipment. © 2018 Wiley Periodicals, Inc.
Alcaine, S D; Tilton, L; Serrano, M A C; Wang, M; Vachet, R W; Nugen, S R
Bacteriophages represent rapid, readily targeted, and easily produced molecular probes for the detection of bacterial pathogens. Molecular biology techniques have allowed researchers to make significant advances in the bioengineering of bacteriophage to further improve speed and sensitivity of detection. Despite their host specificity, bacteriophages have not been meaningfully leveraged in multiplex detection of bacterial pathogens. We propose a proof-of-principal phage-based scheme to enable multiplex detection. Our scheme involves bioengineering bacteriophage to carry a gene for a specific protease, which is expressed during infection of the target cell. Upon lysis, the protease is released to cleave a reporter peptide, and the signal detected. Here we demonstrate the successful (i) modification of T7 bacteriophage to carry tobacco etch virus (TEV) protease; (ii) expression of TEV protease by Escherichia coli following infection by our modified T7, an average of 2000 units of protease per phage are produced during infection; and (iii) proof-of-principle detection of E. coli in 3 h after a primary enrichment via TEV protease activity using a fluorescent peptide and using a designed target peptide for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF MS) analysis. This proof-of-principle can be translated to other phage-protease-peptide combinations to enable multiplex bacterial detection and readily adopted on multiple platforms, like MALDI-TOF MS or fluorescent readers, commonly found in labs.
Wang, Liang; Liu, Zhanzhong; Dai, Shiyun; Yan, Jiawei; Wise, Michael J
The intriguing sit-and-wait hypothesis predicts that bacterial durability in the external environment is positively correlated with their virulence. Since its first proposal in 1987, the hypothesis has been spurring debates in terms of its validity in the field of bacterial virulence. As a special case of the vector-borne transmission versus virulence tradeoff, where vector is now replaced by environmental longevity, there are only sporadic studies over the last three decades showing that environmental durability is possibly linked with virulence. However, no systematic study of these works is currently available and epidemiological analysis has not been updated for the sit-and-wait hypothesis since the publication of Walther and Ewald's (2004) review. In this article, we put experimental evidence, epidemiological data and theoretical analysis together to support the sit-and-wait hypothesis. According to the epidemiological data in terms of gain and loss of virulence (+/-) and durability (+/-) phenotypes, we classify bacteria into four groups, which are: sit-and-wait pathogens (++), vector-borne pathogens (+-), obligate-intracellular bacteria (--), and free-living bacteria (-+). After that, we dive into the abundant bacterial proteomic data with the assistance of bioinformatics techniques in order to investigate the two factors at molecular level thanks to the fast development of high-throughput sequencing technology. Sequences of durability-related genes sourced from Gene Ontology and UniProt databases and virulence factors collected from Virulence Factor Database are used to search 20 corresponding bacterial proteomes in batch mode for homologous sequences via the HMMER software package. Statistical analysis only identified a modest, and not statistically significant correlation between mortality and survival time for eight non-vector-borne bacteria with sit-and-wait potentials. Meanwhile, through between-group comparisons, bacteria with higher host-mortality are
Wang, Liang; Liu, Zhanzhong; Dai, Shiyun; Yan, Jiawei; Wise, Michael J.
The intriguing sit-and-wait hypothesis predicts that bacterial durability in the external environment is positively correlated with their virulence. Since its first proposal in 1987, the hypothesis has been spurring debates in terms of its validity in the field of bacterial virulence. As a special case of the vector-borne transmission versus virulence tradeoff, where vector is now replaced by environmental longevity, there are only sporadic studies over the last three decades showing that environmental durability is possibly linked with virulence. However, no systematic study of these works is currently available and epidemiological analysis has not been updated for the sit-and-wait hypothesis since the publication of Walther and Ewald’s (2004) review. In this article, we put experimental evidence, epidemiological data and theoretical analysis together to support the sit-and-wait hypothesis. According to the epidemiological data in terms of gain and loss of virulence (+/-) and durability (+/-) phenotypes, we classify bacteria into four groups, which are: sit-and-wait pathogens (++), vector-borne pathogens (+-), obligate-intracellular bacteria (--), and free-living bacteria (-+). After that, we dive into the abundant bacterial proteomic data with the assistance of bioinformatics techniques in order to investigate the two factors at molecular level thanks to the fast development of high-throughput sequencing technology. Sequences of durability-related genes sourced from Gene Ontology and UniProt databases and virulence factors collected from Virulence Factor Database are used to search 20 corresponding bacterial proteomes in batch mode for homologous sequences via the HMMER software package. Statistical analysis only identified a modest, and not statistically significant correlation between mortality and survival time for eight non-vector-borne bacteria with sit-and-wait potentials. Meanwhile, through between-group comparisons, bacteria with higher host
Perilla-Henao, Laura M.; Casteel, Clare L.
Hemipteran insects are devastating pests of crops due to their wide host range, rapid reproduction, and ability to transmit numerous plant-infecting pathogens as vectors. While the field of plant–virus–vector interactions has flourished in recent years, plant–bacteria–vector interactions remain poorly understood. Leafhoppers and psyllids are by far the most important vectors of bacterial pathogens, yet there are still significant gaps in our understanding of their feeding behavior, salivary secretions, and plant responses as compared to important viral vectors, such as whiteflies and aphids. Even with an incomplete understanding of plant–bacteria–vector interactions, some common themes have emerged: (1) all known vector-borne bacteria share the ability to propagate in the plant and insect host; (2) particular hemipteran families appear to be incapable of transmitting vector-borne bacteria; (3) all known vector-borne bacteria have highly reduced genomes and coding capacity, resulting in host-dependence; and (4) vector-borne bacteria encode proteins that are essential for colonization of specific hosts, though only a few types of proteins have been investigated. Here, we review the current knowledge on important vector-borne bacterial pathogens, including Xylella fastidiosa, Spiroplasma spp., Liberibacter spp., and ‘Candidatus Phytoplasma spp.’. We then highlight recent approaches used in the study of vector-borne bacteria. Finally, we discuss the application of this knowledge for control and future directions that will need to be addressed in the field of vector–plant–bacteria interactions. PMID:27555855
Manyi-Loh, Christy E.; Mamphweli, Sampson N.; Meyer, Edson L.; Okoh, Anthony I.; Makaka, Golden; Simon, Michael
Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%–99% reduced in the order: Campylobacter sp. (18 days) < Escherichia coli sp. (62 days) < Salmonella sp. (133 days) from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days. PMID:25026086
Manyi-Loh, Christy E.; Mamphweli, Sampson N.; Meyer, Edson L.; Makaka, Golden; Simon, Michael; Okoh, Anthony I.
Cattle manure harbors microbial constituents that make it a potential source of pollution in the environment and infections in humans. Knowledge of, and microbial assessment of, manure is crucial in a bid to prevent public health and environmental hazards through the development of better management practices and policies that should govern manure handling. Physical, chemical and biological methods to reduce pathogen population in manure do exist, but are faced with challenges such as cost, odor pollution, green house gas emission, etc. Consequently, anaerobic digestion of animal manure is currently one of the most widely used treatment method that can help to salvage the above-mentioned adverse effects and in addition, produces biogas that can serve as an alternative/complementary source of energy. However, this method has to be monitored closely as it could be fraught with challenges during operation, caused by the inherent characteristics of the manure. In addition, to further reduce bacterial pathogens to a significant level, anaerobic digestion can be combined with other methods such as thermal, aerobic and physical methods. In this paper, we review the bacterial composition of cattle manure as well as methods engaged in the control of pathogenic microbes present in manure and recommendations that need to be respected and implemented in order to prevent microbial contamination of the environment, animals and humans. PMID:27571092
López Hernández, Yamilé; Yero, Daniel; Pinos-Rodríguez, Juan M.; Gibert, Isidre
Biological disease models can be difficult and costly to develop and use on a routine basis. Particularly, in vivo lung infection models performed to study lung pathologies use to be laborious, demand a great time and commonly are associated with ethical issues. When infections in experimental animals are used, they need to be refined, defined, and validated for their intended purpose. Therefore, alternative and easy to handle models of experimental infections are still needed to test the virulence of bacterial lung pathogens. Because non-mammalian models have less ethical and cost constraints as a subjects for experimentation, in some cases would be appropriated to include these models as valuable tools to explore host–pathogen interactions. Numerous scientific data have been argued to the more extensive use of several kinds of alternative models, such as, the vertebrate zebrafish (Danio rerio), and non-vertebrate insects and nematodes (e.g., Caenorhabditis elegans) in the study of diverse infectious agents that affect humans. Here, we review the use of these vertebrate and non-vertebrate models in the study of bacterial agents, which are considered the principal causes of lung injury. Curiously none of these animals have a respiratory system as in air-breathing vertebrates, where respiration takes place in lungs. Despite this fact, with the present review we sought to provide elements in favor of the use of these alternative animal models of infection to reveal the molecular signatures of host–pathogen interactions. PMID:25699030
Manyi-Loh, Christy E; Mamphweli, Sampson N; Meyer, Edson L; Okoh, Anthony I; Makaka, Golden; Simon, Michael
Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%-99% reduced in the order: Campylobacter sp. (18 days) < Escherichia coli sp. (62 days) < Salmonella sp. (133 days) from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days.
Young, J M
The nomenclature of plant pathogenic bacteria is regulated by the International Code of Nomenclature of Prokaryotes and the International Standards for Naming Pathovars of Phytopathogenic Bacteria. The object of these regulations is to ensure that nomenclature is unambiguous, with correct designations in genera and species and, for many plant pathogens, in infrasubspecies as pathovars. Failure to apply these regulations or to apply them carelessly introduces confusion and misunderstanding over the intended identity of particular pathogens. In this review, bacterial nomenclature is introduced in the context of general communication, with a brief history of the origins of modern bacterial nomenclature. A critical overview of the Code pays most attention to those Rules that are relevant to naming new taxa and new combinations, with comments on common misunderstandings. There follows an account of the application of infrasubspecies, specifically of pathovars as regulated by the Standards for Naming Pathovars. Both the Code and Standards, written almost 30 years ago in response to the exigencies of the time, could be revised to improve clarity. It is not possible for either the Code or the Standards to give formal guidance to the process of translation of pathovars, governed by the Standards, to higher taxonomic ranks, governed by the Code. If the introduction of ambiguity of names is to be avoided in making such translations, then it is the responsibility of individual bacteriologists to consider carefully the nomenclatural implications and outcomes of their proposals.
Nguyen, Thao Thi; Chon, Tae-Soo; Kim, Jaehan; Seo, Young-Su; Heo, Muyoung
Secreted proteins (secretomes) play crucial roles during bacterial pathogenesis in both plant and human hosts. The identification and characterization of secretomes in the two plant pathogens Burkholderia glumae BGR1 and B. gladioli BSR3, which cause diseases in rice such as seedling blight, panicle blight, and grain rot, are important steps to not only understand the disease-causing mechanisms but also find remedies for the diseases. Here, we identified two datasets of secretomes in B. glumae BGR1 and B. gladioli BSR3, which consist of 118 and 111 proteins, respectively, using mass spectrometry approach and literature curation. Next, we characterized the functional properties, potential secretion pathways and sequence information properties of secretomes of two plant pathogens in a comparative analysis by various computational approaches. The ratio of potential non-classically secreted proteins (NCSPs) to classically secreted proteins (CSPs) in B. glumae BGR1 was greater than that in B. gladioli BSR3. For CSPs, the putative hydrophobic regions (PHRs) which are essential for secretion process of CSPs were screened in detail at their N-terminal sequences using hidden Markov model (HMM)-based method. Total 31 pairs of homologous proteins in two bacterial secretomes were indicated based on the global alignment (identity ≥ 70%). Our results may facilitate the understanding of the species-specific features of secretomes in two plant pathogenic Burkholderia species.
Field-applied manure is an important source of pathogenic exposure in surface water bodies for humans and ecological receptors. We analyzed the persistence and decay of fecal indicator bacteria and bacterial pathogens from three sources (cattle, poultry, swine) for agricultural f...
Duris, Joseph W.; Reif, Andrew G.; Donna A. Crouse,; Isaacs, Natasha M.
The occurrence and distribution of fecal indicator bacteria (FIB) and bacterial and protozoan pathogens are controlled by diverse factors. To investigate these factors in Pennsylvania streams, 217 samples were collected quarterly from a 27-station water-quality monitoring network from July 2007 through August 2009. Samples were analyzed for concentrations of Escherichia coli (EC) and enterococci (ENT) indicator bacteria, concentrations of Cryptosporidium oocysts and Giardia cysts, and the presence of four genes related to pathogenic types of EC (eaeA, stx2, stx1, rfbO157) plus three microbial source tracking (MST) gene markers that are also associated with pathogenic ENT and EC (esp, LTIIa, STII). Water samples were concurrently analyzed for basic water chemistry, physical measures of water quality, nutrients, metals, and a suite of 79 organic compounds that included hormones, pharmaceuticals, and antibiotics. For each sample location, stream discharge was measured by using standardized methods at the time of sample collection, and ancillary sample site information, such as land use and geological characteristics, was compiled. Samples exceeding recreational water quality criteria were more likely to contain all measured pathogen genes but notCryptosporidium or Giardia (oo)cysts. FIB and Giardia density and frequency of eaeA gene occurrence were significantly related to season. When discharge at a sampling location was high (>75th percentile of daily mean discharge), there were greater densities of FIB and Giardia, and the stx2, rfbO157, STII, and esp genes were found more frequently than at other discharge conditions. Giardia occurrence was likely related to nonpoint sources, which are highly influential during seasonal overland transport resulting from snowmelt and elevated precipitation in late winter and spring in Pennsylvania. When MST markers of human, swine, or bovine origin were present, samples more frequently carried the eaeA, stx2
Joseph, Baby; Dhas, Berlina; Hena, Vimalin; Raj, Justin
To isolate and identify Bacillus subtilis (B. subtilis) from soil and to characterize and partially purify the bacteriocin. To evaluate the antimicrobial activity against four diabetic foot ulcer bacterial pathogens. Genotypic identification was done based on Bergey's manual of systemic bacteriology. Antimicrobial susceptibility test was done by Kirby-Bauer disc diffusion method. Colonies were identified by colony morphology and biochemical characterization and also compared with MTCC 121 strain. Further identification was done by 16S rRNA sequencing. Inhibitory activities of partially purified bacteriocin on all the DFU isolates were done by agar well diffusion method. The strain was identified to produce bacteriocin by stab overlay assay. Bacteriocin was extracted by organic solvent extraction using chloroform, further purified by HPLC and physical, and chemical characterization was performed. The four isolates showed high level of resistance to amoxyclav and sensitivity to ciprofloxacin. HPLC purification revealed that the extracts are bacteriocin. The phylogenetic tree analysis results showed that the isolate was 99% related to B. subtilis BSF01. The results reveled activity to all the four isolates and high level of activity was seen in case of Klebsiella sp. Partially purified bacteriocin was found to have antimicrobial activity against the four diabetic foot ulcer bacterial pathogens, which can thus be applied as a better drug molecule on further studies. The strain B. subtilis are found to be safe for use and these antimicrobial peptides can be used as an antimicrobial in humans to treat DFU bacterial pathogens. Copyright © 2013 Asian Pacific Tropical Biomedical Magazine. Published by Elsevier B.V. All rights reserved.
Leydet, Brian F.; Liang, Fang-Ting
There are 4 major human-biting tick species in the northeastern United States, which include: Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, and Ixodes scapularis. The black bear is a large mammal that has been shown to be parasitized by all the aforementioned ticks. We investigated the bacterial infections in ticks collected from Louisiana black bears (Ursus americanus subspecies luteolus). Eighty-six ticks were collected from 17 black bears in Louisiana from June 2010 to March 2011. All 4 common human-biting tick species were represented. Each tick was subjected to polymerase chain reaction (PCR) targeting select bacterial pathogens and symbionts. Bacterial DNA was detected in 62% of ticks (n=53). Rickettsia parkeri, the causative agent of an emerging spotted fever group rickettsiosis, was identified in 66% of A. maculatum, 28% of D. variabilis, and 11% of I. scapularis. The Lyme disease bacterium, Borrelia burgdorferi, was detected in 2 I. scapularis, while one Am. americanum was positive for Borrelia bissettii, a putative human pathogen. The rickettsial endosymbionts Candidatus Rickettsia andeanae, rickettsial endosymbiont of I. scapularis, and Rickettsia amblyommii were detected in their common tick hosts at 21%, 39%, and 60%, respectively. All ticks were PCR-negative for Anaplasma phagocytophilum, Ehrlichia spp., and Babesia microti. This is the first reported detection of R. parkeri in vector ticks in Louisiana; we also report the novel association of R. parkeri with I. scapularis. Detection of both R. parkeri and Bo. burgdorferi in their respective vectors in Louisiana demands further investigation to determine potential for human exposure to these pathogens. PMID:23415850
Ghosh, Gairika; Reddy, Jayavardhana; Sambhare, Susmit; Sen, Ranjan
Rho is a hexameric molecular motor that functions as a conserved transcription terminator in the majority of bacterial species and is a potential drug target. Psu is a bacteriophage P4 capsid protein that inhibits Escherichia coli Rho by obstructing its ATPase and translocase activities. In this study, we explored the anti-Rho activity of Psu for Rho proteins from different pathogens. Sequence alignment and homology modeling of Rho proteins from pathogenic bacteria revealed the conserved nature of the Psu-interacting regions in all these proteins. We chose Rho proteins from various pathogens, including Mycobacterium smegmatis , Mycobacterium bovis , Mycobacterium tuberculosis , Xanthomonas campestris , Xanthomonas oryzae , Corynebacterium glutamicum , Vibrio cholerae , Salmonella enterica , and Pseudomonas syringae The purified recombinant Rho proteins of these organisms showed variable rates of ATP hydrolysis on poly(rC) as the substrate and were capable of releasing RNA from the E. coli transcription elongation complexes. Psu was capable of inhibiting these two functions of all these Rho proteins. In vivo pulldown assays revealed direct binding of Psu with many of these Rho proteins. In vivo expression of psu induced killing of M. smegmatis , M. bovis , X. campestris , and E. coli expressing S. enterica Rho indicating Psu-induced inhibition of Rho proteins of these strains under physiological conditions. We propose that the "universal" inhibitory function of the Psu protein against the Rho proteins from both Gram-negative and Gram-positive bacteria could be useful for designing peptides with antimicrobial functions and that these peptides could contribute to synergistic antibiotic treatment of the pathogens by compromising the Rho functions. IMPORTANCE Bacteriophage-derived protein factors modulating different bacterial processes could be converted into unique antimicrobial agents. Bacteriophage P4 capsid protein Psu is an inhibitor of the E. coli transcription
Pfaller, M. A.; Sader, H. S.; Rhomberg, P. R.
ABSTRACT The in vitro activities of delafloxacin and comparator antimicrobial agents against 6,485 bacterial isolates collected from medical centers in Europe and the United States in 2014 were tested. Delafloxacin was the most potent agent tested against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus, Streptococcus pneumoniae, viridans group streptococci, and beta-hemolytic streptococci and had activity similar to that of ciprofloxacin and levofloxacin against certain members of the Enterobacteriaceae. Overall, the broadest coverage of the tested pathogens (Gram-positive cocci and Gram-negative bacilli) was observed with meropenem and tigecycline in both Europe and the United States. Delafloxacin was shown to be active against organisms that may be encountered in acute bacterial skin and skin structure infections, respiratory infections, and urinary tract infections. PMID:28167542
Pfaller, M A; Sader, H S; Rhomberg, P R; Flamm, R K
The in vitro activities of delafloxacin and comparator antimicrobial agents against 6,485 bacterial isolates collected from medical centers in Europe and the United States in 2014 were tested. Delafloxacin was the most potent agent tested against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus , Streptococcus pneumoniae , viridans group streptococci, and beta-hemolytic streptococci and had activity similar to that of ciprofloxacin and levofloxacin against certain members of the Enterobacteriaceae Overall, the broadest coverage of the tested pathogens (Gram-positive cocci and Gram-negative bacilli) was observed with meropenem and tigecycline in both Europe and the United States. Delafloxacin was shown to be active against organisms that may be encountered in acute bacterial skin and skin structure infections, respiratory infections, and urinary tract infections. Copyright © 2017 Pfaller et al.
Davin-Regli, Anne; Pagès, Jean-Marie
Enterobacter aerogenes and E. cloacae have been reported as important opportunistic and multiresistant bacterial pathogens for humans during the last three decades in hospital wards. These Gram-negative bacteria have been largely described during several outbreaks of hospital-acquired infections in Europe and particularly in France. The dissemination of Enterobacter sp. is associated with the presence of redundant regulatory cascades that efficiently control the membrane permeability ensuring the bacterial protection and the expression of detoxifying enzymes involved in antibiotic degradation/inactivation. In addition, these bacterial species are able to acquire numerous genetic mobile elements that strongly contribute to antibiotic resistance. Moreover, this particular fitness help them to colonize several environments and hosts and rapidly and efficiently adapt their metabolism and physiology to external conditions and environmental stresses. Enterobacter is a versatile bacterium able to promptly respond to the antibiotic treatment in the colonized patient. The balance of the prevalence, E. aerogenes versus E. cloacae, in the reported hospital infections during the last period, questions about the horizontal transmission of mobile elements containing antibiotic resistance genes, e.g., the efficacy of the exchange of resistance genes Klebsiella pneumoniae to Enterobacter sp. It is also important to mention the possible role of antibiotic use in the treatment of bacterial infectious diseases in this E. aerogenes/E. cloacae evolution.
Davin-Regli, Anne; Pagès, Jean-Marie
Enterobacter aerogenes and E. cloacae have been reported as important opportunistic and multiresistant bacterial pathogens for humans during the last three decades in hospital wards. These Gram-negative bacteria have been largely described during several outbreaks of hospital-acquired infections in Europe and particularly in France. The dissemination of Enterobacter sp. is associated with the presence of redundant regulatory cascades that efficiently control the membrane permeability ensuring the bacterial protection and the expression of detoxifying enzymes involved in antibiotic degradation/inactivation. In addition, these bacterial species are able to acquire numerous genetic mobile elements that strongly contribute to antibiotic resistance. Moreover, this particular fitness help them to colonize several environments and hosts and rapidly and efficiently adapt their metabolism and physiology to external conditions and environmental stresses. Enterobacter is a versatile bacterium able to promptly respond to the antibiotic treatment in the colonized patient. The balance of the prevalence, E. aerogenes versus E. cloacae, in the reported hospital infections during the last period, questions about the horizontal transmission of mobile elements containing antibiotic resistance genes, e.g., the efficacy of the exchange of resistance genes Klebsiella pneumoniae to Enterobacter sp. It is also important to mention the possible role of antibiotic use in the treatment of bacterial infectious diseases in this E. aerogenes/E. cloacae evolution. PMID:26042091
Chang, Hsiao-Han; Cohen, Ted; Grad, Yonatan H.; Hanage, William P.; O'Brien, Thomas F.
SUMMARY Many studies report the high prevalence of multiply drug-resistant (MDR) strains. Because MDR infections are often significantly harder and more expensive to treat, they represent a growing public health threat. However, for different pathogens, different underlying mechanisms are traditionally used to explain these observations, and it is unclear whether each bacterial taxon has its own mechanism(s) for multidrug resistance or whether there are common mechanisms between distantly related pathogens. In this review, we provide a systematic overview of the causes of the excess of MDR infections and define testable predictions made by each hypothetical mechanism, including experimental, epidemiological, population genomic, and other tests of these hypotheses. Better understanding the cause(s) of the excess of MDR is the first step to rational design of more effective interventions to prevent the origin and/or proliferation of MDR. PMID:25652543
Nguyen, Nghi; Wilson, Danny W; Nagalingam, Gayathri; Triccas, James A; Schneider, Elena K; Li, Jian; Velkov, Tony; Baell, Jonathan
In this study, a structure-activity relationship (SAR) compound series based on the NDH-2 inhibitor diphenyleneiodonium (DPI) was synthesised. Compounds were evaluated primarily for in vitro efficacy against Gram-positive and Gram-negative bacteria, commonly responsible for nosocomial and community acquired infections. In addition, we also assessed the activity of these compounds against Mycobacterium tuberculosis (Tuberculosis) and Plasmodium spp. (Malaria). This led to the discovery of highly potent compounds active against bacterial pathogens and malaria parasites in the low nanomolar range, several of which were significantly less toxic to mammalian cells. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
Clemens-Grisham, Rachel Andrea; Bhattacharya, Sharmila; Wade, William
After spaceflight, the number of immune cells is reduced in humans. In other research models, including Drosophila, not only is there a reduction in the number of plasmatocytes, but expression of immune-related genes is also changed after spaceflight. These observations suggest that the immune system is compromised after exposure to microgravity. It has also been reported that there is a change in virulence of some bacterial pathogens after spaceflight. We recently observed that samples of gram-negative S. marcescens retrieved from spaceflight is more virulent than ground controls, as determined by reduced survival and increased bacterial growth in the host. We were able to repeat this finding of increased virulence after exposure to simulated microgravity using the rotating wall vessel, a ground based analog to microgravity. With the ground and spaceflight samples, we looked at involvement of the Toll and Imd pathways in the Drosophila host in fighting infection by ground and spaceflight samples. We observed that Imd-pathway mutants were more susceptible to infection by the ground bacterial samples, which aligns with the known role of this pathway in fighting infections by gram-negative bacteria. When the Imd-pathway mutants were infected with the spaceflight sample, however, they exhibited the same susceptibility as seen with the ground control bacteria. Interestingly, all mutant flies show the same susceptibility to the spaceflight bacterial sample as do wild type flies. This suggests that neither humoral immunity pathway is effectively able to counter the increased pathogenicity of the space-flown S. marcescens bacteria.
Dohrmann, Anja B; Baumert, Susann; Klingebiel, Lars; Weiland, Peter; Tebbe, Christoph C
Microbial conversion of organic waste or harvested plant material into biogas has become an attractive technology for energy production. Biogas is produced in reactors under anaerobic conditions by a consortium of microorganisms which commonly include bacteria of the genus Clostridium. Since the genus Clostridium also harbors some highly pathogenic members in its phylogenetic cluster I, there has been some concern that an unintended growth of such pathogens might occur during the fermentation process. Therefore this study aimed to follow how process parameters affect the diversity of Bacteria in general, and the diversity of Clostridium cluster I members in particular. The development of both communities was followed in model biogas reactors from start-up during stable methanogenic conditions. The biogas reactors were run with either cattle or pig manures as substrates, and both were operated at mesophilic and thermophilic conditions. The structural diversity was analyzed independent of cultivation using a PCR-based detection of 16S rRNA genes and genetic profiling by single-strand conformation polymorphism (SSCP). Genetic profiles indicated that both bacterial and clostridial communities evolved in parallel, and the community structures were highly influenced by both substrate and temperature. Sequence analysis of 16S rRNA genes recovered from prominent bands from SSCP profiles representing Clostridia detected no pathogenic species. Thus, this study gave no indication that pathogenic clostridia would be enriched as dominant community members in biogas reactors fed with manure.
Tosheva-Daskalova, Konstantsa; Strateva, Tanya Vasileva; Mitov, Ivan Gergov; Gergova, Raina Tzvetanova
Background/aim: This study aimed to investigate the correlation between the prevalence of problematic pathogens and the clinical status of women with bacterial vaginosis (BV). Materials and methods: Gardnerella vaginalis, Atopobium vaginae, and Mobiluncus spp. were detected using a multiplex PCR assay, and their role in the infection of Bulgarian women with clinically heterogeneous BV was evaluated. Results: The predominant BV-associated pathogen identified was G. vaginalis with an incidence of 98.39%, followed by A. vaginae (68.05%) and Mobiluncus spp. at 17.01%. The coexistence of A. vaginae and G. vaginalis was more common in women with discharge (in 72.04%) and in patients with chronic recurrent BV than among asymptomatic or newly diagnosed BV cases (P < 0.05). Mobiluncus spp. was detected mostly in coinfections, in association with Trichomonas vaginalis. The coinfections were predominantly related to recurrent BV and with complications (P < 0.05). Conclusion: This is the first study about the correlation between problematic pathogens and clinically heterogeneous BV in Bulgarian women. High frequency of infection with key BV-related pathogens was observed in childbearing women. The incidence was shown to often correlate with coexistent T. vaginalis, with severity of infection, and with complicated and recurrent BV after unsuccessful treatments. Screening should be considered in reproductive health programs.
Schinner, Tim; Letzner, Adrian; Liedtke, Stefan; Castro, Felipe D; Eydelnant, Irwin A; Tufenkji, Nathalie
The protection of groundwater supplies from microbial contamination necessitates a solid understanding of the key factors controlling the migration and retention of pathogenic organisms through the subsurface environment. The transport behavior of five waterborne pathogens was examined using laboratory-scale columns packed with clean quartz at two solution ionic strengths (10 mM and 30 mM). Escherichia coli O157:H7 and Yersinia enterocolitica were selected as representative Gram-negative pathogens, Enterococcus faecalis was selected as a representative Gram-positive organism, and two cyanobacteria (Microcystis aeruginosa and Anabaena flos-aquae) were also studied. The five organisms exhibit differing attachment efficiencies to the quartz sand. The surface (zeta) potential of the microorganisms was characterized over a broad range of pH values (2-8) at two ionic strengths (10 mM and 30 mM). These measurements are used to evaluate the observed attachment behavior within the context of the DLVO theory of colloidal stability. To better understand the possible link between bacterial transport in model quartz sand systems and natural soil matrices, additional experiments were conducted with two of the selected organisms using columns packed with loamy sand obtained from an agricultural field. This investigation highlights the need for further characterization of waterborne pathogen surface properties and transport behavior over a broader range of environmentally relevant conditions. Copyright 2008 Elsevier Ltd. All rights reserved.
Spanò, Stefania; Gao, Xiang; Hannemann, Sebastian; Lara-Tejero, María; Galán, Jorge E
Cell-autonomous defense mechanisms are potent strategies that protect individual cells against intracellular pathogens. The Rab-family GTPase Rab32 was previously shown to restrict the intracellular human pathogen Salmonella Typhi, but its potential broader role in antimicrobial defense remains unknown. We show that Rab32 represents a general cell-autonomous, antimicrobial defense that is counteracted by two Salmonella effectors. Mice lacking Rab-32 or its nucleotide exchange factor BLOC-3 are permissive to S. Typhi infection and exhibit increased susceptibility to S. Typhimurium. S. Typhimurium counters this defense pathway by delivering two type III secretion effectors, SopD2, a Rab32 GAP, and GtgE, a specific Rab32 protease. An S. Typhimurium mutant strain lacking these two effectors exhibits markedly reduced virulence, which is fully restored in BLOC-3-deficient mice. These results demonstrate that a cell-autonomous, Rab32-dependent host defense pathway plays a central role in the defense against vacuolar pathogens and describe a mechanism evolved by a bacterial pathogen to counter it. Copyright © 2016 Elsevier Inc. All rights reserved.
Singh, Gulshan; Manohar, Murli; Adegoke, Anthony Ayodeji; Stenström, Thor Axel; Shanker, Rishi
The lack of microbiologically safe water in underdeveloped nations is the prime cause of infectious disease outbreaks. The need for the specific identification and detection of microorganisms encourages the development of advanced, rapid, sensitive and highly specific methods for the monitoring of pathogens and management of potential risk to human health. The rapid molecular assays based on detection of specific molecular signatures offer advantages over conventional methods in terms of specificity and sensitivity but require complex instrumentation and skilled personnel. Nanotechnology is an emerging area and provides a robust approach for the identification of pathogenic microorganism utilizing the peculiar properties of nanomaterials, i.e. small size (1-100 nm) and large surface area. This emerging technology promises to fulfill the urgent need of a novel strategy to enhance the bacterial identification and quantitation in the environment. In this context, the peculiar properties of gold nanoparticles, their plasmonic shifts, and changes in magnetic properties have been utilized for the simple and cost-effective detection of bacterial nucleic acids, antigens and toxins with quite improved sensitivity. One of the promising leads to develop an advance detection method might be the coupling of nucleic acid aptamers (capable of interacting specifically with bacteria, protozoa, and viruses) with nanomaterials. Such aptamer-nano conjugate can be used for the specific recognition of infectious agents in different environmental matrices. This review summarizes the application of nanotechnology in the area of pathogen detection and discusses the prospects of coupling nucleic acid aptamers with nanoparticles for the specific detection of targeted pathogens.
Jiang, Lu Xi; Ren, Hong Yu; Zhou, Hai Jian; Zhao, Si Hong; Hou, Bo Yan; Yan, Jian Ping; Qin, Tian; Chen, Yu
Lower respiratory tract infections continue to pose a significant threat to human health. It is important to accurately and rapidly detect respiratory bacteria. To compensate for the limits of current respiratory bacteria detection methods, we developed a combination of multiplex polymerase chain reaction (PCR) and capillary electrophoresis (MPCE) assay to detect thirteen bacterial pathogens responsible for lower respiratory tract infections, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Mycoplasma pneumoniae, Legionella spp., Bordetella pertussis, Mycobacterium tuberculosis complex, Corynebacterium diphtheriae, and Streptococcus pyogenes. Three multiplex PCR reactions were built, and the products were analyzed by capillary electrophoresis using the high-throughput DNA analyzer. The specificity of the MPCE assay was examined and the detection limit was evaluated using DNA samples from each bacterial strain and the simulative samples of each strain. This assay was further evaluated using 152 clinical specimens and compared with real-time PCR reactions. For this assay, three nested-multiplex-PCRs were used to detect these clinical specimens. The detection limits of the MPCE assay for the 13 pathogens were very low and ranged from 10-7 to 10-2 ng/μL. Furthermore, analysis of the 152 clinical specimens yielded a specificity ranging from 96.5%-100.0%, and a sensitivity of 100.0% for the 13 pathogens. This study revealed that the MPCE assay is a rapid, reliable, and high-throughput method with high specificity and sensitivity. This assay has great potential in the molecular epidemiological survey of respiratory pathogens. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.
Murdoch, Sarah L.; Trunk, Katharina; English, Grant; Fritsch, Maximilian J.; Pourkarimi, Ehsan; Coulthurst, Sarah J.
The type VI secretion system (T6SS) is the most recently described and least understood of the protein secretion systems of Gram-negative bacteria. It is widely distributed and has been implicated in the virulence of various pathogens, but its mechanism and exact mode of action remain to be defined. Additionally there have been several very recent reports that some T6SSs can target bacteria rather than eukaryotic cells. Serratia marcescens is an opportunistic enteric pathogen, a class of bacteria responsible for a significant proportion of hospital-acquired infections. We describe the identification of a functional T6SS in S. marcescens strain Db10, the first report of type VI secretion by an opportunist enteric bacterium. The T6SS of S. marcescens Db10 is active, with secretion of Hcp to the culture medium readily detected, and is expressed constitutively under normal growth conditions from a large transcriptional unit. Expression of the T6SS genes did not appear to be dependent on the integrity of the T6SS. The S. marcescens Db10 T6SS is not required for virulence in three nonmammalian virulence models. It does, however, exhibit dramatic antibacterial killing activity against several other bacterial species and is required for S. marcescens to persist in a mixed culture with another opportunist pathogen, Enterobacter cloacae. Importantly, this antibacterial killing activity is highly strain specific, with the S. marcescens Db10 T6SS being highly effective against another strain of S. marcescens with a very similar and active T6SS. We conclude that type VI secretion plays a crucial role in the competitiveness, and thus indirectly the virulence, of S. marcescens and other opportunistic bacterial pathogens. PMID:21890705
Urbanus, Malene L; Quaile, Andrew T; Stogios, Peter J; Morar, Mariya; Rao, Chitong; Di Leo, Rosa; Evdokimova, Elena; Lam, Mandy; Oatway, Christina; Cuff, Marianne E; Osipiuk, Jerzy; Michalska, Karolina; Nocek, Boguslaw P; Taipale, Mikko; Savchenko, Alexei; Ensminger, Alexander W
Pathogens deliver complex arsenals of translocated effector proteins to host cells during infection, but the extent to which these proteins are regulated once inside the eukaryotic cell remains poorly defined. Among all bacterial pathogens, Legionella pneumophila maintains the largest known set of translocated substrates, delivering over 300 proteins to the host cell via its Type IVB, Icm/Dot translocation system. Backed by a few notable examples of effector-effector regulation in L. pneumophila, we sought to define the extent of this phenomenon through a systematic analysis of effector-effector functional interaction. We used Saccharomyces cerevisiae, an established proxy for the eukaryotic host, to query > 108,000 pairwise genetic interactions between two compatible expression libraries of ~330 L. pneumophila-translocated substrates. While capturing all known examples of effector-effector suppression, we identify fourteen novel translocated substrates that suppress the activity of other bacterial effectors and one pair with synergistic activities. In at least nine instances, this regulation is direct-a hallmark of an emerging class of proteins called metaeffectors, or "effectors of effectors". Through detailed structural and functional analysis, we show that metaeffector activity derives from a diverse range of mechanisms, shapes evolution, and can be used to reveal important aspects of each cognate effector's function. Metaeffectors, along with other, indirect, forms of effector-effector modulation, may be a common feature of many intracellular pathogens-with unrealized potential to inform our understanding of how pathogens regulate their interactions with the host cell. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.
Cryan, Paul M.; Cunningham, Andrew A.; Fooks, Anthony R.; Hayman, David T.S.; Luis, Angela D.; Peel, Alison J.; Plowright, Raina K.; Wood, James L.N.
Bats are sources of high viral diversity and high-profile zoonotic viruses worldwide. Although apparently not pathogenic in their reservoir hosts, some viruses from bats severely affect other mammals, including humans. Examples include severe acute respiratory syndrome coronaviruses, Ebola and Marburg viruses, and Nipah and Hendra viruses. Factors underlying high viral diversity in bats are the subject of speculation. We hypothesize that flight, a factor common to all bats but to no other mammals, provides an intensive selective force for coexistence with viral parasites through a daily cycle that elevates metabolism and body temperature analogous to the febrile response in other mammals. On an evolutionary scale, this host–virus interaction might have resulted in the large diversity of zoonotic viruses in bats, possibly through bat viruses adapting to be more tolerant of the fever response and less virulent to their natural hosts. PMID:24750692
O'Shea, Thomas J.; Cryan, Paul M.; Cunningham, Andrew A.; Fooks, Anthony R.; Hayman, David T.S.; Luis, Angela D.; Peel, Alison J.; Plowright, Raina K.; Wood, James L.N.
Bats are sources of high viral diversity and high-profile zoonotic viruses worldwide. Although apparently not pathogenic in their reservoir hosts, some viruses from bats severely affect other mammals, including humans. Examples include severe acute respiratory syndrome coronaviruses, Ebola and Marburg viruses, and Nipah and Hendra viruses. Factors underlying high viral diversity in bats are the subject of speculation. We hypothesize that flight, a factor common to all bats but to no other mammals, provides an intensive selective force for coexistence with viral parasites through a daily cycle that elevates metabolism and body temperature analogous to the febrile response in other mammals. On an evolutionary scale, this host–virus interaction might have resulted in the large diversity of zoonotic viruses in bats, possibly through bat viruses adapting to be more tolerant of the fever response and less virulent to their natural hosts.
Srinivasan, Usha; Ponnaluri, Sreelatha; Villareal, Lisa; Gillespie, Brenda; Wen, Ai; Miles, Arianna; Bucholz, Brigette; Marrs, Carl F; Iyer, Ram K; Misra, Dawn; Foxman, Betsy
We demonstrate the feasibility of using qPCR on DNA extracted from vaginal Gram stain slides to estimate the presence and relative abundance of specific bacterial pathogens. We first tested Gram stained slides spiked with a mix of 10(8) cfu/ml of Escherichia coli and 10(5) cfu/ml of Lactobacillus acidophilus. Primers were designed for amplification of total and species-specific bacterial DNA based on 16S ribosomal gene regions. Sample DNA was pre-amplified with nearly full length 16S rDNA ribosomal gene fragment, followed by quantitative PCR with genera and species-specific 16S rDNA primers. Pre-amplification PCR increased the bacterial amounts; relative proportions of Escherichia coli and Lactobacillus recovered from spiked slides remained unchanged. We applied this method to forty two archived Gram stained slides available from a clinical trial of cerclage in pregnant women at high risk of preterm birth. We found a high correlation between Nugent scores based on bacterial morphology of Lactobacillus, Gardenerella and Mobiluncus and amounts of quantitative PCR estimated genus specific DNA (rrn copies) from Gram stained slides. Testing of a convenience sample of eight paired vaginal swabs and Gram stains freshly collected from healthy women found similar qPCR generated estimates of Lactobacillus proportions from Gram stained slides and vaginal swabs. Archived Gram stained slides collected from large scale epidemiologic and clinical studies represent a valuable, untapped resource for research on the composition of bacterial communities that colonize human mucosal surfaces.
Soobhany, Nuhaa; Mohee, Romeela; Garg, Vinod Kumar
Waste management strategies for organic residues, such as composting and vermicomposting, have been implemented in some developed and developing countries to solve the problem of organic solid waste (OSW). Yet, these biological treatment technologies do not always result in good quality compost or vermicompost with regards to sanitation capacity owing to the presence of bacterial pathogenic substances in objectionable concentrations. The presence of pathogens in soil conditioners poses a potential health hazard and their occurrence is of particular significance in composts and/or vermicomposts produced from organic materials. Past and present researches demonstrated a high-degree of agreement that various pathogens survive after the composting of certain OSW but whether similar changes in bacterial pathogenic loads arise during vermitechnology has not been thoroughly elucidated. This review garners information regarding the status of various pathogenic bacteria which survived or diffused after the composting process compared to the status of these pathogens after the vermicomposting of OSW with the aim of achieving sanitation goals. This work is also indispensable for the specification of compost quality guidelines concerning pathogen loads which would be specific to treatment technology. It was hypothesized that vermicomposting process for OSW can be efficacious in sustaining the existence of pathogenic organisms most specifically; human pathogens under safety levels. In summary, earthworms can be regarded as a way of obliterating pathogenic bacteria from OSW in a manner equivalent to earthworm gut transit mechanism which classifies vermicomposting as a promising sanitation technique in comparison to composting processes. Copyright © 2017 Elsevier Ltd. All rights reserved.
Harris, Jordan Lee; Balci, Yilmaz
Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship.
Szeredi, Levente; Jánosi, Szilárd; Pálfi, Vilmos
The infectious origin of fatal cases of calf pneumonia was studied in 48 calves from 27 different herds on postmortem examination. Lung tissue samples were examined by pathological, histological, bacterial culture, virus isolation and immunohistochemical methods for the detection of viral and bacterial infections. Pneumonia was diagnosed in 47/48 cases and infectious agents were found in 40/47 (85%) of those cases. The presence of multiple respiratory pathogens in 23/40 (57.5%) cases indicated the complex origin of fatal calf pneumonia. The most important respiratory pathogens were Mannheimia-Pasteurella in 36/40 (90%) cases, followed by Arcanobacterium pyogenes in 16/40 (40%) cases, Mycoplasma bovis in 12/40 (30%) cases, and bovine respiratory syncytial virus in 4/40 (10%) cases. Histophilus somni was detected in 2/40 (5%) cases, while bovine herpesvirus-1, bovine viral diarrhoea virus and parainfluenza virus-3 were each found in 1/40 (2.5%) case. Mastadenovirus, bovine coronavirus, influenza A virus or Chlamydiaceae were not detected.
Bhattacharya, Debanjana; Bhattacharya, Semantee; Patra, Madhu Manti; Chakravorty, Somnath; Sarkar, Soumyadev; Chakraborty, Writachit; Koley, Hemanta; Gachhui, Ratan
The emergence of multi-drug-resistant enteric pathogens has prompted the scientist community to explore the therapeutic potentials of traditional foods and beverages. The present study was undertaken to investigate the efficacy of Kombucha, a fermented beverage of sugared black tea, against enterotoxigenic Escherichia coli, Vibrio cholerae, Shigella flexneri and Salmonella Typhimurium followed by the identification of the antibacterial components present in Kombucha. The antibacterial activity was evaluated by determining the inhibition zone diameter, minimal inhibitory concentration and minimal bactericidal concentration. Kombucha fermented for 14 days showed maximum activity against the bacterial strains. Its ethyl acetate extract was found to be the most effective upon sequential solvent extraction of the 14-day Kombucha. This potent ethyl acetate extract was then subjected to thin layer chromatography for further purification of antibacterial ingredients which led to the isolation of an active polyphenolic fraction. Catechin and isorhamnetin were detected as the major antibacterial compounds present in this polyphenolic fraction of Kombucha by High Performance Liquid Chromatography. Catechin, one of the primary antibacterial polyphenols in tea was also found to be present in Kombucha. But isorhamnetin is not reported to be present in tea, which may thereby suggest the role of fermentation process of black tea for its production in Kombucha. To the best of our knowledge, this is the first report on the presence of isorhamnetin in Kombucha. The overall study suggests that Kombucha can be used as a potent antibacterial agent against entero-pathogenic bacterial infections, which mainly is attributed to its polyphenolic content.
Ebner, Florian; Ivin, Masa; Kratochvill, Franz; Gratz, Nina; Villunger, Andreas; Sixt, Michael
Protective responses against pathogens require a rapid mobilization of resting neutrophils and the timely removal of activated ones. Neutrophils are exceptionally short-lived leukocytes, yet it remains unclear whether the lifespan of pathogen-engaged neutrophils is regulated differently from that in the circulating steady-state pool. Here, we have found that under homeostatic conditions, the mRNA-destabilizing protein tristetraprolin (TTP) regulates apoptosis and the numbers of activated infiltrating murine neutrophils but not neutrophil cellularity. Activated TTP-deficient neutrophils exhibited decreased apoptosis and enhanced accumulation at the infection site. In the context of myeloid-specific deletion of Ttp, the potentiation of neutrophil deployment protected mice against lethal soft tissue infection with Streptococcus pyogenes and prevented bacterial dissemination. Neutrophil transcriptome analysis revealed that decreased apoptosis of TTP-deficient neutrophils was specifically associated with elevated expression of myeloid cell leukemia 1 (Mcl1) but not other antiapoptotic B cell leukemia/lymphoma 2 (Bcl2) family members. Higher Mcl1 expression resulted from stabilization of Mcl1 mRNA in the absence of TTP. The low apoptosis rate of infiltrating TTP-deficient neutrophils was comparable to that of transgenic Mcl1-overexpressing neutrophils. Our study demonstrates that posttranscriptional gene regulation by TTP schedules the termination of the antimicrobial engagement of neutrophils. The balancing role of TTP comes at the cost of an increased risk of bacterial infections. PMID:28504646
Bertuccini, Lucia; Russo, Rosario; Iosi, Francesca; Superti, Fabiana
The human vagina is colonized by a variety of microbes. Lactobacilli are the most common, mainly in healthy women; however, the microbiota composition can change rapidly, leading to infection or to a state in which potential pathogenic microorganisms co-exist with other commensals. In premenopausal women, urogenital infections, such as bacterial vaginosis and aerobic vaginitis, remain an important health problem. Treatment of these infections involves different kind of antibiotics; however, the recurrence rate remains high, and it must be also underlined that antibiotics are unable to spontaneously restore normal flora characterized by an abundant community of Lactobacilli. The main limitation is the inability to offer a long-term defensive barrier, thus facilitating relapses and recurrences. We report here the antimicrobial activities of two commercially existing Lactobacillus strains, Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus GLA-14 strains and their combination (Respecta® probiotic blend) against four different pathogens responsible for both bacterial vaginosis ( Gardenerella vaginalis and Atopobium vaginae) and aerobic vaginitis ( Staphylococcus aureus and Escherichia coli) by co-culturing assay. The probiotic combination, even if resulting in a different microbicidal activity against the different strains tested, demonstrated the efficacy of combined Lactobacillus strain treatment.
Bertuccini, Lucia; Russo, Rosario; Iosi, Francesca; Superti, Fabiana
The human vagina is colonized by a variety of microbes. Lactobacilli are the most common, mainly in healthy women; however, the microbiota composition can change rapidly, leading to infection or to a state in which potential pathogenic microorganisms co-exist with other commensals. In premenopausal women, urogenital infections, such as bacterial vaginosis and aerobic vaginitis, remain an important health problem. Treatment of these infections involves different kind of antibiotics; however, the recurrence rate remains high, and it must be also underlined that antibiotics are unable to spontaneously restore normal flora characterized by an abundant community of Lactobacilli. The main limitation is the inability to offer a long-term defensive barrier, thus facilitating relapses and recurrences. We report here the antimicrobial activities of two commercially existing Lactobacillus strains, Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus GLA-14 strains and their combination (Respecta® probiotic blend) against four different pathogens responsible for both bacterial vaginosis (Gardenerella vaginalis and Atopobium vaginae) and aerobic vaginitis (Staphylococcus aureus and Escherichia coli) by co-culturing assay. The probiotic combination, even if resulting in a different microbicidal activity against the different strains tested, demonstrated the efficacy of combined Lactobacillus strain treatment. PMID:28580872
Harris, Jordan Lee; Balci, Yilmaz
Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship. PMID:25815838
Dayao, Denise Ann Estarez; Seddon, Jennifer M; Gibson, Justine S; Blackall, Patrick J; Turni, Conny
Macrolides are often used to treat and control bacterial pathogens causing respiratory disease in pigs. This study analyzed the whole genome sequences of one clinical isolate of Actinobacillus pleuropneumoniae, Haemophilus parasuis, Pasteurella multocida, and Bordetella bronchiseptica, all isolated from Australian pigs to identify the mechanism underlying the elevated minimum inhibitory concentrations (MICs) for erythromycin, tilmicosin, or tulathromycin. The H. parasuis assembled genome had a nucleotide transition at position 2059 (A to G) in the six copies of the 23S rRNA gene. This mutation has previously been associated with macrolide resistance but this is the first reported mechanism associated with elevated macrolide MICs in H. parasuis. There was no known macrolide resistance mechanism identified in the other three bacterial genomes. However, strA and sul2, aminoglycoside and sulfonamide resistance genes, respectively, were detected in one contiguous sequence (contig 1) of A. pleuropneumoniae assembled genome. This contig was identical to plasmids previously identified in Pasteurellaceae. This study has provided one possible explanation of elevated MICs to macrolides in H. parasuis. Further studies are necessary to clarify the mechanism causing the unexplained macrolide resistance in other Australian pig respiratory pathogens including the role of efflux systems, which were detected in all analyzed genomes.
Agunos, Agnes; Pierson, F William; Lungu, Bwalya; Dunn, Patricia A; Tablante, Nathaniel
Emerging and re-emerging diseases are continuously diagnosed in poultry species. A few of these diseases are known to cross the species barrier, thus posing a public health risk and an economic burden. We identified and synthesized global evidence for poultry nonfoodborne zoonoses to better understand these diseases in people who were exposed to different poultry-related characteristics (e.g., occupational or nonoccupational, operational types, poultry species, outbreak conditions, health status of flocks). This review builds on current knowledge on poultry zoonoses/potentially zoonotic agents transmitted via the nonfoodborne route. It also identifies research gaps and potential intervention points within the poultry industry to reduce zoonotic transmission by using various knowledge synthesis tools such as systematic review (SR) and qualitative (descriptive) and quantitative synthesis methods (i.e., meta-analysis). Overall, 1663 abstracts were screened and 156 relevant articles were selected for further review. Full articles (in English) were retrieved and critically appraised using routine SR methods. In total, eight known zoonotic diseases were reviewed: avian influenza (AI) virus (n = 85 articles), Newcastle disease virus (n = 8), West Nile virus (WNV, n = 2), avian Chlamydia (n = 24), Erysipelothrix rhusiopathiae (n = 3), methicillin-resistant Staphylococcus aureus (MRSA, n = 15), Ornithonyssus sylvarium (n = 4), and Microsporum gallinae (n = 3). In addition, articles on other viral poultry pathogens (n = 5) and poultry respiratory allergens derived from mites and fungi (n = 7) were reviewed. The level of investigations (e.g., exposure history, risk factor, clinical disease in epidemiologically linked poultry, molecular studies) to establish zoonotic linkages varied across disease agents and across studies. Based on the multiple outcome measures captured in this review, AI virus seems to be the poultry zoonotic pathogen that may have considerable and
Kingsley, Mark T.
The threat to American interests from terrorists is not limited to attacks against humans. Terrorists might seek to inflict damage to the U.S. economy by attacking our agricultural sector. Infection of commodity crops by bacterial or fungal crop pathogens could adversely impact U.S. agriculture, either directly from damage to crops or indirectly from damage to our ability to export crops suspected of contamination. Recognizing a terrorist attack against U.S. agriculture, to be able to prosecute the terrorists, is among the responsibilities of the members of Hazardous Material Response Unit (HMRU) of the Federal Bureau of Investigation (FBI). Nucleic acid analysismore » of plant pathogen strains by the use of polymerase chain reaction (PCR) amplification techniques is a powerful method for determining the exact identity of pathogens, as well as their possible region of origin. This type of analysis, however, requires that PCR assays be developed specific to each particular pathogen strain, and analysis protocols developed that are specific to the particular instrument used for detection. The objectives of the work described here were threefold: 1) to assess the potential terrorist threat to U.S. agricultural crops, 2) to determine whether suitable assays exist to monitor that threat, and 3) where assays are needed for priority plant pathogen threats, to modify or develop those assays for use by specialists at the HMRU. The assessment of potential threat to U.S. commodity crops and the availability of assays for those threats were described in detail in the Technical Requirements Document (9) and will be summarized in this report. This report addresses development of specific assays identified in the Technical Requirements Document, and offers recommendations for future development to ensure that HMRU specialists will be prepared with the PCR assays they need to protect against the threat of economic terrorism.« less
Kingsley, Mark T
The threat to American interests from terrorists is not limited to attacks against humans. Terrorists might seek to inflict damage to the U.S. economy by attacking our agricultural sector. Infection of commodity crops by bacterial or fungal crop pathogens could adversely impact U.S. agriculture, either directly from damage to crops or indirectly from damage to our ability to export crops suspected of contamination. Recognizing a terrorist attack against U.S. agriculture, to be able to prosecute the terrorists, is among the responsibilities of the members of Hazardous Material Response Unit (HMRU) of the Federal Bureau of Investigation (FBI). Nucleic acid analysismore » of plant pathogen strains by the use of polymerase chain reaction (PCR) amplification techniques is a powerful method for determining the exact identity of pathogens, as well as their possible region of origin. This type of analysis, however, requires that PCR assays be developed specific to each particular pathogen strain, an d analysis protocols developed that are specific to the particular instrument used for detection. The objectives of the work described here were threefold: (1) to assess the potential terrorist threat to U.S. agricultural crops, (2) to determine whether suitable assays exist to monitor that threat, and (3) where assays are needed for priority plant pathogen threats, to modify or develop those assays for use by specialists at the HMRU. The assessment of potential threat to U.S. commodity crops and the availability of assays for those threats were described in detail in the Technical Requirements Document (9) and will be summarized in this report. This report addresses development of specific assays identified in the Technical Requirements Document, and offers recommendations for future development to ensure that HMRU specialists will be prepared with the PCR assays they need to protect against the threat of economic terrorism.« less
Romanowska, Magdalena; Nowak, Iwona; Brydak, Lidia; Wojtyla, Andrzej
Since 1997, human infections with highly pathogenic zoonotic avian influenza viruses have shown that the risk of influenza pandemic is significant. In Europe, infections caused by the highly pathogenic avian influenza A(H7N7) virus were confirmed in the human population in 2003 in the Netherlands. Moreover, outbreaks of A(H5N1) infections were observed in wild and farm birds in different European regions, including Poland in 2006-2008. This study presents 16 patients in Poland from whom clinical specimens were collected and tested for A(H5N1) highly pathogenic avian influenza. This article shows the results of laboratory tests and discusses the legitimacy of the collection and testing of the specimens. All patients were negative for A(H5N1) infection. Nevertheless, only two patients met clinical and epidemiological criteria from the avian influenza case definition. The conclusion is that there is still a strong necessity for increasing the awareness of medical and laboratory staff, as well as the awareness of some occupational groups about human infections with avian influenza viruses, including the importance of seasonal influenza vaccination. It should also be emphasized that in the case of patients suspected of being infected with avian influenza, the information about clinical symptoms is insufficient and must be accompanied by a wide epidemiological investigation.
Mumford, Sonia; Patterson, Chris; Evered, J.; Brunson, Ray; Levine, J.; Winton, J.
Examination of finfish populations for viral and bacterial pathogens is an important component of fish disease control programs worldwide. Two methods are commonly used for collecting tissue samples for bacteriological culture, the currently accepted standards for detection of bacterial fish pathogens. The method specified in the Office International des Epizooties Manual of Diagnostic Tests for Aquatic Animals permits combining renal and splenic tissues from as many as 5 fish into pooled samples. The American Fisheries Society (AFS) Blue Book/US Fish and Wildlife Service (USFWS) Inspection Manual specifies the use of a bacteriological loop for collecting samples from the kidney of individual fish. An alternative would be to more fully utilize the pooled samples taken for virology. If implemented, this approach would provide substantial savings in labor and materials. To compare the relative performance of the AFS/USFWS method and this alternative approach, cultures of Yersinia ruckeri were used to establish low-level infections in groups of rainbow trout (Oncorhynchus mykiss) that were sampled by both methods. Yersinia ruckeri was cultured from 22 of 37 groups by at least 1 method. The loop method yielded 18 positive groups, with 1 group positive in the loop samples but negative in the pooled samples. The pooled samples produced 21 positive groups, with 4 groups positive in the pooled samples but negative in the loop samples. There was statistically significant agreement (Spearman coefficient 0.80, P < 0.001) in the relative ability of the 2 sampling methods to permit detection of low-level bacterial infections of rainbow trout.
Bacteriophages (also called 'phages') are viruses that kill bacteria. They are arguably the oldest (3 billion years old, by some estimates) and most ubiquitous (total number estimated to be 10(30) -10(32) ) known organisms on Earth. Phages play a key role in maintaining microbial balance in every ecosystem where bacteria exist, and they are part of the normal microflora of all fresh, unprocessed foods. Interest in various practical applications of bacteriophages has been gaining momentum recently, with perhaps the most attention focused on using them to improve food safety. That approach, called 'phage biocontrol', typically includes three main types of applications: (i) using phages to treat domesticated livestock in order to reduce their intestinal colonization with, and shedding of, specific bacterial pathogens; (ii) treatments for decontaminating inanimate surfaces in food-processing facilities and other food establishments, so that foods processed on those surfaces are not cross-contaminated with the targeted pathogens; and (iii) post-harvest treatments involving direct applications of phages onto the harvested foods. This mini-review primarily focuses on the last type of intervention, which has been gaining the most momentum recently. Indeed, the results of recent studies dealing with improving food safety, and several recent regulatory approvals of various commercial phage preparations developed for post-harvest food safety applications, strongly support the idea that lytic phages may provide a safe, environmentally-friendly, and effective approach for significantly reducing contamination of various foods with foodborne bacterial pathogens. However, some important technical and nontechnical problems may need to be addressed before phage biocontrol protocols can become an integral part of routine food safety intervention strategies implemented by food industries in the USA. © 2013 Society of Chemical Industry.
Beaume, Marie; Köhler, Thilo; Fontana, Thierry; Tognon, Mikael; Renzoni, Adriana; van Delden, Christian
Background: Chronic airway infection by Pseudomonas aeruginosa considerably contributes to lung tissue destruction and impairment of pulmonary function in cystic-fibrosis (CF) patients. Complex interplays between P. aeruginosa and other co-colonizing pathogens including Staphylococcus aureus, Burkholderia sp., and Klebsiella pneumoniae may be crucial for pathogenesis and disease progression. Methods: We generated a library of PA14 transposon insertion mutants to identify P. aeruginosa genes required for exploitative and direct competitions with S. aureus, Burkholderia cenocepacia, and K. pneumoniae. Results: Whereas wild-type PA14 inhibited S. aureus growth, two transposon insertions located in pqsC and carB, resulted in reduced growth inhibition. PqsC is involved in the synthesis of 4-hydroxy-2-alkylquinolines (HAQs), a family of molecules having antibacterial properties, while carB is a key gene in pyrimidine biosynthesis. The carB mutant was also unable to grow in the presence of B. cepacia and K. pneumoniae but not Escherichia coli and S. epidermidis. We further identified a transposon insertion in purF, encoding a key enzyme of purine metabolism. This mutant displayed a severe growth deficiency in the presence of Gram-negative but not of Gram-positive bacteria. We identified a beneficial interaction in a bioA transposon mutant, unable to grow on rich medium. This growth defect could be restored either by addition of biotin or by co-culturing the mutant in the presence of K. pneumoniae or E. coli. Conclusion: Complex interactions take place between the various bacterial species colonizing CF-lungs. This work identified both detrimental and beneficial interactions occurring between P. aeruginosa and three other respiratory pathogens involving several major metabolic pathways. Manipulating these pathways could be used to interfere with bacterial interactions and influence the colonization by respiratory pathogens. PMID:25954256
Urbanus, Malene L.; Quaile, Andrew T.; Stogios, Peter J.; ...
Pathogens deliver complex arsenals of translocated effector proteins to host cells during infection, but the extent to which these proteins are regulated once inside the eukaryotic cell remains poorly defined. Among all bacterial pathogens, Legionella pneumophila maintains the largest known set of translocated substrates, delivering over 300 proteins to the host cell via its Type IVB, Icm/Dot translocation system. Backed by a few notable examples of effector–effector regulation in L. pneumophila, we sought to define the extent of this phenomenon through a systematic analysis of effector–effector functional interaction. We used Saccharomyces cerevisiae, an established proxy for the eukaryotic host, tomore » query > 108,000 pairwise genetic interactions between two compatible expression libraries of ~330 L. pneumophila–translocated substrates. While capturing all known examples of effector–effector suppression, we identify fourteen novel translocated substrates that suppress the activity of other bacterial effectors and one pair with synergistic activities. In at least nine instances, this regulation is direct—a hallmark of an emerging class of proteins called metaeffectors, or “effectors of effectors”. Through detailed structural and functional analysis, we show that metaeffector activity derives from a diverse range of mechanisms, shapes evolution, and can be used to reveal important aspects of each cognate effector's function. Here, metaeffectors, along with other, indirect, forms of effector–effector modulation, may be a common feature of many intracellular pathogens—with unrealized potential to inform our understanding of how pathogens regulate their interactions with the host cell.« less
Su, Jianmei; Zou, Xia; Huang, Liangbo; Bai, Tenglong; Liu, Shu; Yuan, Meng; Chou, Shan-Ho; He, Ya-Wen; Wang, Haihong; He, Jin
Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases. PMID:27193392
Ebrahimi, Azizollah; Hemati, Majid; Shabanpour, Ziba; Habibian Dehkordi, Saeed; Bahadoran, Shahab; Lotfalian, Sharareh; Khubani, Shahin
Background: Resistance toward quaternary ammonium compounds (QACs) is widespread among a diverse range of microorganisms and is facilitated by several mechanisms such as biofilm formation. Objectives: In this study, the effects of benzalkonium chloride on planktonic growth and biofilm formation by some field isolates of animal bacterial pathogens were investigated. Materials and Methods: Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus aureus and Streptococcus agalactiae (10 isolates of each) were examined for effects of benzalkonium chloride on biofilm formation and planktonic growth using microtiter plates. For all the examined strains in the presence of benzalkonium chloride, biofilm development and planktonic growth were affected at the same concentrations of disinfectant. Results: The means of strains growth increase after the minimal inhibitory concentration (MIC) were significant in all the bacteria (except for E. coli in 1/32 and S. agalactiae in of 1/8 MIC). Biofilm formation increased with decrease of antiseptics concentration; a significant increase was found in all the samples. The most turbidity related to S. aureus and the least to Salmonella. Conclusions: Bacterial resistance against quaternary ammonium compounds is increasing which can increase the bacterial biofilm formation. PMID:25793094
Fyfe, Corey; O’Brien, William; Hackel, Meredith; Minyard, Mary Beth; Waites, Ken B.; Dubois, Jacques; Murphy, Timothy M.; Slee, Andrew M.; Weiss, William J.; Sutcliffe, Joyce A.
ABSTRACT TP-271 is a novel, fully synthetic fluorocycline antibiotic in clinical development for the treatment of respiratory infections caused by susceptible and multidrug-resistant pathogens. TP-271 was active in MIC assays against key community respiratory Gram-positive and Gram-negative pathogens, including Streptococcus pneumoniae (MIC90 = 0.03 µg/ml), methicillin-sensitive Staphylococcus aureus (MSSA; MIC90 = 0.25 µg/ml), methicillin-resistant S. aureus (MRSA; MIC90 = 0.12 µg/ml), Streptococcus pyogenes (MIC90 = 0.03 µg/ml), Haemophilus influenzae (MIC90 = 0.12 µg/ml), and Moraxella catarrhalis (MIC90 ≤0.016 µg/ml). TP-271 showed activity (MIC90 = 0.12 µg/ml) against community-acquired MRSA expressing Panton-Valentine leukocidin (PVL). MIC90 values against Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia pneumoniae were 0.004, 1, and 4 µg/ml, respectively. TP-271 was efficacious in neutropenic and immunocompetent animal pneumonia models, generally showing, compared to the burden at the start of dosing, ~2 to 5 log10 CFU reductions against MRSA, S. pneumoniae, and H. influenzae infections when given intravenously (i.v.) and ~1 to 4 log10 CFU reductions when given orally (p.o.). TP-271 was potent against key community-acquired bacterial pneumonia (CABP) pathogens and was minimally affected, or unaffected, by tetracycline-specific resistance mechanisms and fluoroquinolone or macrolide drug resistance phenotypes. IMPORTANCE Rising resistance rates for macrolides, fluoroquinolones, and β-lactams in the most common pathogens associated with community-acquired bacterial pneumonia (CABP) are of concern, especially for cases of moderate to severe infections in vulnerable populations such as the very young and the elderly. New antibiotics that are active against multidrug-resistant Streptococcus pneumoniae and Staphylococcus aureus are needed for use in the empirical treatment of the most severe forms of this disease. TP-271 is a promising
Kochi, Yuto; Miyashita, Atsushi; Tsuchiya, Kohsuke; Mitsuyama, Masao; Sekimizu, Kazuhisa; Kaito, Chikara
Invertebrate animal species that can withstand temperatures as high as 37°C, the human body temperature, are limited. In the present study, we utilized the two-spotted cricket, Gryllus bimaculatus, which lives in tropical and subtropical regions, as an animal model of human pathogenic bacterial infection. Injection of Pseudomonas aeruginosa or Staphylococcus aureus into the hemolymph killed crickets. Injected P. aeruginosa or S. aureus proliferated in the hemolymph until the cricket died. The ability of these pathogenic bacteria to kill the crickets was blocked by the administration of antibiotics. S. aureus gene-knockout mutants of virulence factors, including cvfA, agr and srtA, exhibited decreased killing ability compared with the parent strain. The dose at which 50% of crickets were killed by P. aeruginosa or S. aureus was not decreased at 37°C compared with that at 27°C. Injection of Listeria monocytogenes, which upregulates toxin expression at 37°C, killed crickets, and the dose at which 50% of crickets were killed was decreased at 37°C compared with that at 27°C. These findings suggest that the two-spotted cricket is a useful model animal for evaluating the virulence properties of various human pathogenic bacteria at variable temperature including 37°C. © FEMS 2016. All rights reserved. For permissions, please e-mail: firstname.lastname@example.org.
Salvucci, A. E.; Fuka, D. R.; Marjerison, R. D.; Hay, A. G.; Zhang, W.; Caballero, L. A.; Zevi, Y.; Richards, B. K.; Steenhuis, T. S.
Pathogenic bacteria, such as Escherichia coli and Salmonella sp., are responsible for many deaths worldwide every year. Their survival in the natural environment is enhanced by the production of biofilms, which provide a resistance to environmental stresses. However, it remains unclear how these biofilms affect the bacterias' ability to move through the soil matrix and potentially contaminate groundwater or water from drainage systems. In this presentation, we discuss the role of thin aggregative fimbriae (curli), a key biofilm component, on transport through porous media. An experiment was performed consisting of 96 sand columns created using a deep-well microtiter plate. We used well-characterized strains of E. coli, one with the ability to form curli and one without. Pulsing the E. coli strains through the sand column, mimicking natural leaching processes, showed less transport, by greater retention, in the strains that produce curli versus those strains that do not. In addition, when cultured in conditions unfavorable to curli production, transport between strains did not differ significantly. These preliminary results indicate that curli, and to a larger extent biofilms, could be an important component influencing the transport of bacterial strains through the soil matrix. This determination of pathogens' ability to move through the environment, as related to how well they form biofilms, will facilitate a better understanding of the fate of pathogenic bacteria in the environment.
De La Fuente, Leonardo; Parker, Jennifer K.; Oliver, Jonathan E.; Granger, Shea; Brannen, Phillip M.; van Santen, Edzard; Cobine, Paul A.
Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547
Kane, Trevor L.; Carothers, Katelyn E.; Lee, Shaun W.
Background Staphylococcus aureus is a major bacterial pathogen capable of causing a range of infections in humans from gastrointestinal disease, skin and soft tissue infections, to severe outcomes such as sepsis. Staphylococcal infections in humans can be frequent and recurring, with treatments becoming less effective due to the growing persistence of antibiotic resistant S. aureus strains. Due to the prevalence of antibiotic resistance, and the current limitations on antibiotic development, an active and highly promising avenue of research has been to develop strategies to specifically inhibit the activity of virulence factors produced S. aureus as an alternative means to treat disease. Objective In this review we specifically highlight several major virulence factors produced by S. aureus for which recent advances in antivirulence approaches may hold promise as an alternative means to treating diseases caused by this pathogen. Strategies to inhibit virulence factors can range from small molecule inhibitors, to antibodies, to mutant and toxoid forms of the virulence proteins. Conclusion The major prevalence of antibiotic resistant strains of S. aureus combined with the lack of new antibiotic discoveries highlight the need for vigorous research into alternative strategies to combat diseases caused by this highly successful pathogen. Current efforts to develop specific antivirulence strategies, vaccine approaches, and alternative therapies for treating severe disease caused by S. aureus have the potential to stem the tide against the limitations that we face in the post-antibiotic era. PMID:27894236
Miller, Melissa A.; Byrne, Barbara A.; Jang, Spencer S.; Dodd, Erin M.; Dorfmeier, Elene; Harris, Michael D.; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A.; Miller, Woutrina A.
Although protected for nearly a century, California’s sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health. PMID:19720009
Zenebe, Tizazu; Kannan, Subbaram; Yilma, Daniel; Beyene, Getenet
Presence of microorganisms in the circulating blood whether continuously or intermittently is a threat to every organ in the body. Approximately 200,000 cases of bacteraemia occur annually with mortality rates ranging from 20-50%. Early diagnosis and appropriate treatment of these infections can make the difference between life and death. The aim of the present study was to determine the bacterial flora of the blood stream infections and their antibiotic susceptibility pattern. A cross sectional study was conducted on 260 adult febrile patients in Jimma University Specialized Hospital from 27 October 2009 to 26 March 2010. The positive blood cultures were examined and the organisms were identified as per standard procedures. Antimicrobial testing was performed for all isolates by disk diffusion techniques, according to Clinical Laboratory Standards Institute guide lines. The data was analyzed using SPSS for windows version 16 and Microsoft Office Excel. From the total of two hundred sixty blood specimens only 23(8.8%) were positive to seven different types of bacteria. The isolated bacteria were: Coagulase negative staphylococci 6(26.1%), S. aureus 5 (21.7%), S. pyogens 3 (13.0%), E. coli 4(17.4%), K. pneumoniae 3(13.0%), Salmonella spp. 1(4.3%), and Citrobacter spp. 1(4.3%). The isolates showed high rates of resistance to most antibiotics tested. The range of resistance for gram positive bacteria were 0% to 85.7%, and for gram negative from 0% to 100%. None of the isolates were resistance to ciprofloxacin and ceftriaxone. Our study result showed the presence of invasive bacterial pathogens with high rate of resistance to most commonly used antibiotics used to treat bacterial infections. Therefore, timely investigation of bacterial flora of the blood stream infections and monitoring of their antibiotic resistance pattern plays an important role in reduction of the incidence of blood stream infections.
Wiles, Travis J.; Norton, J. Paul; Russell, Colin W.; Dalley, Brian K.; Fischer, Kael F.; Mulvey, Matthew A.
Strains of Extraintestinal Pathogenic Escherichia c oli (ExPEC) exhibit an array of virulence strategies and are a major cause of urinary tract infections, sepsis and meningitis. Efforts to understand ExPEC pathogenesis are challenged by the high degree of genetic and phenotypic variation that exists among isolates. Determining which virulence traits are widespread and which are strain-specific will greatly benefit the design of more effective therapies. Towards this goal, we utilized a quantitative genetic footprinting technique known as transposon insertion sequencing (Tn-seq) in conjunction with comparative pathogenomics to functionally dissect the genetic repertoire of a reference ExPEC isolate. Using Tn-seq and high-throughput zebrafish infection models, we tracked changes in the abundance of ExPEC variants within saturated transposon mutant libraries following selection within distinct host niches. Nine hundred and seventy bacterial genes (18% of the genome) were found to promote pathogen fitness in either a niche-dependent or independent manner. To identify genes with the highest therapeutic and diagnostic potential, a novel Trait Enrichment Analysis (TEA) algorithm was developed to ascertain the phylogenetic distribution of candidate genes. TEA revealed that a significant portion of the 970 genes identified by Tn-seq have homologues more often contained within the genomes of ExPEC and other known pathogens, which, as suggested by the first axiom of molecular Koch's postulates, is considered to be a key feature of true virulence determinants. Three of these Tn-seq-derived pathogen-associated genes—a transcriptional repressor, a putative metalloendopeptidase toxin and a hypothetical DNA binding protein—were deleted and shown to independently affect ExPEC fitness in zebrafish and mouse models of infection. Together, the approaches and observations reported herein provide a resource for future pathogenomics-based research and highlight the diversity of
Background The US CDC estimates over 2 million foodborne illnesses are annually caused by 4 major enteropathogens: non-typhoid Salmonella spp., Campylobacter spp., Shigella spp. and Yersinia enterocoltica. While data suggest a number of costly and morbid chronic sequelae associated with these infections, pathogen-specific risk estimates are lacking. We utilized a US Department of Defense medical encounter database to evaluate the risk of several gastrointestinal disorders following select foodborne infections. Methods We identified subjects with acute gastroenteritis between 1998 to 2009 attributed to Salmonella (nontyphoidal) spp., Shigella spp., Campylobacter spp. or Yersinia enterocolitica and matched each with up to 4 unexposed subjects. Medical history was analyzed for the duration of military service time (or a minimum of 1 year) to assess for incident chronic gastrointestinal disorders. Relative risks were calculated using modified Poisson regression while controlling for the effect of covariates. Results A total of 1,753 pathogen-specific gastroenteritis cases (Campylobacter: 738, Salmonella: 624, Shigella: 376, Yersinia: 17) were identified and followed for a median of 3.8 years. The incidence (per 100,000 person-years) of PI sequelae among exposed was as follows: irritable bowel syndrome (IBS), 3.0; dyspepsia, 1.8; constipation, 3.9; gastroesophageal reflux disease (GERD), 9.7. In multivariate analyses, we found pathogen-specific increased risk of IBS, dyspepsia, constipation and GERD. Conclusions These data confirm previous studies demonstrating risk of chronic gastrointestinal sequelae following bacterial enteric infections and highlight additional preventable burden of disease which may inform better food security policies and practices, and prompt further research into pathogenic mechanisms. PMID:23510245
Khalaf, Eman M; Raizada, Manish N
The cucurbit vegetables, including cucumbers, melons and pumpkins, have been cultivated for thousands of years without fungicides. However, their seed germination stage is prone to be infected by soil-borne fungal and oomycete pathogens. Endophytes are symbionts that reside inside plant tissues including seeds. Seed endophytes are founders of the juvenile plant microbiome and can promote host defense at seed germination and later stages. We previously isolated 169 bacterial endophytes associated with seeds of diverse cultivated cucurbits. We hypothesized that these endophytes can antagonize major fungal and oomycete pathogens. Here we tested the endophytes for in vitro antagonism (dual culture assays) against important soil-borne pathogens ( Rhizoctonia solani , Fusarium graminearum , Phytophthora capsici , Pythium aphanideratum ). The endophytes were also assayed in planta (leaf disk and detached leaf bioassays) for antagonism against a foliar pathogen of global importance, Podosphaera fuliginea , the causative agent of cucurbit powdery mildew. The endophytes were further tested in vitro for secretion of volatile organic compounds (VOCs) known to induce plant defense. Extracellular ribonuclease activity was also tested, as a subset of pathogenesis-related (PR) proteins of plant hosts implicated in suppression of fungal pathogens, displays ribonuclease activity. An unexpected majority of the endophytes (70%, 118/169) exhibited antagonism to the five phytopathogens, of which 68% (50/73) of in vitro antagonists belong to the genera Bacillus and Paenibacillus . All Lactococcus and Pantoea endophytes exhibited anti-oomycete activity. However, amongst the most effective inoculants against Podosphaera fuliginea were Pediococcus and Pantoea endophytes. Interestingly, 67% (113/169) of endophytes emitted host defense inducing VOCs (acetoin/diacetyl) and 62% (104/169) secreted extracellular ribonucleases in vitro , respectively. These results show that seeds of cultivated
Khalaf, Eman M.; Raizada, Manish N.
The cucurbit vegetables, including cucumbers, melons and pumpkins, have been cultivated for thousands of years without fungicides. However, their seed germination stage is prone to be infected by soil-borne fungal and oomycete pathogens. Endophytes are symbionts that reside inside plant tissues including seeds. Seed endophytes are founders of the juvenile plant microbiome and can promote host defense at seed germination and later stages. We previously isolated 169 bacterial endophytes associated with seeds of diverse cultivated cucurbits. We hypothesized that these endophytes can antagonize major fungal and oomycete pathogens. Here we tested the endophytes for in vitro antagonism (dual culture assays) against important soil-borne pathogens (Rhizoctonia solani, Fusarium graminearum, Phytophthora capsici, Pythium aphanidermatum). The endophytes were also assayed in planta (leaf disk and detached leaf bioassays) for antagonism against a foliar pathogen of global importance, Podosphaera fuliginea, the causative agent of cucurbit powdery mildew. The endophytes were further tested in vitro for secretion of volatile organic compounds (VOCs) known to induce plant defense. Extracellular ribonuclease activity was also tested, as a subset of pathogenesis-related (PR) proteins of plant hosts implicated in suppression of fungal pathogens, displays ribonuclease activity. An unexpected majority of the endophytes (70%, 118/169) exhibited antagonism to the five phytopathogens, of which 68% (50/73) of in vitro antagonists belong to the genera Bacillus and Paenibacillus. All Lactococcus and Pantoea endophytes exhibited anti-oomycete activity. However, amongst the most effective inoculants against Podosphaera fuliginea were Pediococcus and Pantoea endophytes. Interestingly, 67% (113/169) of endophytes emitted host defense inducing VOCs (acetoin/diacetyl) and 62% (104/169) secreted extracellular ribonucleases in vitro, respectively. These results show that seeds of cultivated cucurbits
Richards, Gary P
Bacteriophages have been proposed as an alternative to antibiotic usage and several studies on their application in aquaculture have been reported. This review highlights progress to date on phage therapies for the following fish and shellfish diseases and associated pathogens: hemorrhagic septicemia (Aeromonas hydrophila) in loaches, furunculosis (Aeromonas salmonicida) in trout and salmon, edwardsiellosis (Edwardsiella tarda) in eel, columnaris disease (Flavobacterium columnare) in catfish, rainbow trout fry syndrome or cold water disease (Flavobacterium psychrophilum) in trout and salmon, lactococcosis (Lactococcus spp.) in yellowtail, ulcerative skin lesions (Pseudomonas aeruginosa) in freshwater catfish, bacterial hemorrhagic ascites disease (Pseudomonas plecoglossicida) in ayu fish, streptococcosis (Streptococcus iniae) in flounder, and luminescent vibriosis (Vibrio harveyi) in shrimp. Information is reviewed on phage specificity, host resistance, routes of administration, and dosing of fish and shellfish. Limitations in phage research are described and recommended guidelines are provided for conducting future phage studies involving fish and shellfish. PMID:26713223
Doss, Janis; Culbertson, Kayla; Hahn, Delilah; Camacho, Joanna; Barekzi, Nazir
Since the discovery of bacteriophage in the early 1900s, there have been numerous attempts to exploit their innate ability to kill bacteria. The purpose of this report is to review current findings and new developments in phage therapy with an emphasis on bacterial diseases of marine organisms, humans, and plants. The body of evidence includes data from studies investigating bacteriophage in marine and land environments as modern antimicrobial agents against harmful bacteria. The goal of this paper is to present an overview of the topic of phage therapy, the use of phage-derived protein therapy, and the hosts that bacteriophage are currently being used against, with an emphasis on the uses of bacteriophage against marine, human, animal and plant pathogens.
Glycogen synthase kinase 3β (GSK3β) plays a fundamental role during the inflammatory response induced by bacteria. Depending on the pathogen and its virulence factors, the type of cell and probably the context in which the interaction between host cells and bacteria takes place, GSK3β may promote or inhibit inflammation. The goal of this review is to discuss recent findings on the role of the inhibition or activation of GSK3β and its modulation of the inflammatory signaling in monocytes/macrophages and epithelial cells at the transcriptional level, mainly through the regulation of nuclear factor-kappaB (NF-κB) activity. Also included is a brief overview on the importance of GSK3 in non-inflammatory processes during bacterial infection. PMID:22691598
Shamaila, Shahzadi; Zafar, Noshin; Riaz, Saira; Sharif, Rehana; Nazir, Jawad; Naseem, Shahzad
Enteric bacterial human pathogens, i.e., Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae, are the major cause of diarrheal infections in children and adults. Their structure badly affects the human immune system. It is important to explore new antibacterial agents instead of antibiotics for treatment. This project is an attempt to explain how gold nanoparticles affect these bacteria. We investigated the important role of the mean particle size, and the inhibition of a bacterium is dose-dependent. Ultra Violet (UV)-visible spectroscopy revealed the size of chemically synthesized gold nanoparticle as 6–40 nm. Atomic force microscopy (AFM) analysis confirmed the size and X-ray diffractometry (XRD) analysis determined the polycrystalline nature of gold nanoparticles. The present findings explained how gold nanoparticles lyse Gram-negative and Gram-positive bacteria. PMID:28335198
Cortés-Vieyra, Ricarda; Bravo-Patiño, Alejandro; Valdez-Alarcón, Juan J; Juárez, Marcos Cajero; Finlay, B Brett; Baizabal-Aguirre, Víctor M
Glycogen synthase kinase 3β (GSK3β) plays a fundamental role during the inflammatory response induced by bacteria. Depending on the pathogen and its virulence factors, the type of cell and probably the context in which the interaction between host cells and bacteria takes place, GSK3β may promote or inhibit inflammation. The goal of this review is to discuss recent findings on the role of the inhibition or activation of GSK3β and its modulation of the inflammatory signaling in monocytes/macrophages and epithelial cells at the transcriptional level, mainly through the regulation of nuclear factor-kappaB (NF-κB) activity. Also included is a brief overview on the importance of GSK3 in non-inflammatory processes during bacterial infection.
Legrand, Matthieu; Klijn, Eva; Payen, Didier; Ince, Can
Sepsis results from the interaction between a host and an invading pathogen. The microcirculatory dysfunction is now considered central in the development of the often deadly multiple organ dysfunction syndrome in septic shock patients. The microcirculatory flow shutdown and flow shunting leading to oxygen demand and supply mismatch at the cellular level and the local activation of inflammatory pathways resulting from the leukocyte-endothelium interactions are both features of the sepsis-induced microcirculatory dysfunction. Although the host response through the inflammatory and immunologic response appears to be critical, there are also evidences that Gram-positive and Gram-negative bacteria can exert different effects at the microcirculatory level. In this review we discuss available data on the potential bacterial-specific microcirculatory alterations observed during sepsis.
Hill, Geoffrey E.; Josefson, Chloe C.; Armbruster, Jonathan W.
ABSTRACT While direct contact may sometimes be sufficient to allow a pathogen to jump into a new host species, in other cases, fortuitously adaptive mutations that arise in the original donor host are also necessary. Viruses have been the focus of most host shift studies, so less is known about the importance of ecological versus evolutionary processes to successful bacterial host shifts. Here we tested whether direct contact with the novel host was sufficient to enable the mid-1990s jump of the bacterium Mycoplasma gallisepticum from domestic poultry to house finches (Haemorhous mexicanus). We experimentally inoculated house finches with two genetically distinct M. gallisepticum strains obtained either from poultry (Rlow) or from house finches (HF1995) during an epizootic outbreak. All 15 house finches inoculated with HF1995 became infected, whereas Rlow successfully infected 12 of 15 (80%) inoculated house finches. Comparisons among infected birds showed that, relative to HF1995, Rlow achieved substantially lower bacterial loads in the host respiratory mucosa and was cleared faster. Furthermore, Rlow-infected finches were less likely to develop clinical symptoms than HF1995-infected birds and, when they did, displayed milder conjunctivitis. The lower infection success of Rlow relative to HF1995 was not, however, due to a heightened host antibody response to Rlow. Taken together, our results indicate that contact between infected poultry and house finches was not, by itself, sufficient to explain the jump of M. gallisepticum to house finches. Instead, mutations arising in the original poultry host would have been necessary for successful pathogen emergence in the novel finch host. PMID:29311238
Reducing Escherichia coli O157:H7 in livestock manures before application to cropland is critical for reducing the risk of foodborne illness associated with produce. Our objective was to determine the fate of naturally occurring E. coli O157:H7 and other pathogens during minimally managed on-farm bo...
Aims: To evaluate natural terpene compounds for antimicrobial activities and determine if these compounds could be used to control microbial activities and pathogens in production animal facilities. Methods and Results: Thymol, geraniol, glydox, linalool, pine oil, plinol, and terpineol were teste...
Arnal, L.; Longo, G.; Stupar, P.; Castez, M. F.; Cattelan, N.; Salvarezza, R. C.; Yantorno, O. M.; Kasas, S.; Vela, M. E.
Bacterial adhesion is the first and a significant step in establishing infection. This adhesion normally occurs in the presence of flow of fluids. Therefore, bacterial adhesins must be able to provide high strength interactions with their target surface in order to maintain the adhered bacteria under hydromechanical stressing conditions. In the case of B. pertussis, a Gram-negative bacterium responsible for pertussis, a highly contagious human respiratory tract infection, an important protein participating in the adhesion process is a 220 kDa adhesin named filamentous haemagglutinin (FHA), an outer membrane and also secreted protein that contains recognition domains to adhere to ciliated respiratory epithelial cells and macrophages. In this work, we obtained information on the cell-surface localization and distribution of the B. pertussis adhesin FHA using an antibody-functionalized AFM tip. Through the analysis of specific molecular recognition events we built a map of the spatial distribution of the adhesin which revealed a non-homogeneous pattern. Moreover, our experiments showed a force induced reorganization of the adhesin on the surface of the cells, which could explain a reinforced adhesive response under external forces. This single-molecule information contributes to the understanding of basic molecular mechanisms used by bacterial pathogens to cause infectious disease and to gain insights into the structural features by which adhesins can act as force sensors under mechanical shear conditions.Bacterial adhesion is the first and a significant step in establishing infection. This adhesion normally occurs in the presence of flow of fluids. Therefore, bacterial adhesins must be able to provide high strength interactions with their target surface in order to maintain the adhered bacteria under hydromechanical stressing conditions. In the case of B. pertussis, a Gram-negative bacterium responsible for pertussis, a highly contagious human respiratory tract
Ruedl, C; Frühwirth, M; Wick, G; Wolf, H
We have investigated the local immune response of the BALB/c mouse respiratory tract after oral immunization with a bacterial lysate of seven common respiratory pathogens. After two immunization on five consecutive days, we examined the immunoglobulin (immunoglobulin G [IgG], IgM, and IgA) secretion rates of cells isolated from the lungs and compared them with those of spleen cells of orally immunized and nonimmunized animals by using a new test system based on time-resolved fluorescence. The procedure followed the principle of the classical ELISPOT test with nitrocellulose-bottomed microtiter plates, but europium (Eu3+)-linked streptavidin rather than enzyme-conjugated streptavidin was used, with the advantage of quantifying secreted immunoglobulins instead of detecting single antibody-secreting cells. Lymphocytes isolated from the lungs of treated animals revealed significant increases in total and antigen-specific IgA synthesis compared with the rates of the controls, whereas IgG and IgM production rates showed no remarkable differences. In addition, the sera of treated mice revealed higher antigen-specific IgA titers but not increased IgM and IgG levels. We conclude that priming the gut-associated lymphoid tissue with bacterial antigens of pneumotropic microorganisms can elicit an enhanced IgA response in a distant mucosal effector site, such as the respiratory tract, according to the concept of a common mucosa-associated immune system. PMID:7496936
Beres, Stephen B; Richter, Ellen W; Nagiec, Michal J; Sumby, Paul; Porcella, Stephen F; DeLeo, Frank R; Musser, James M
In recent years we have studied the relationship between strain genotypes and patient phenotypes in group A Streptococcus (GAS), a model human bacterial pathogen that causes extensive morbidity and mortality worldwide. We have concentrated our efforts on serotype M3 organisms because these strains are common causes of pharyngeal and invasive infections, produce unusually severe invasive infections, and can exhibit epidemic behavior. Our studies have been hindered by the lack of genome-scale phylogenies of multiple GAS strains and whole-genome sequences of multiple serotype M3 strains recovered from individuals with defined clinical phenotypes. To remove some of these impediments, we sequenced to closure the genome of four additional GAS strains and conducted comparative genomic resequencing of 12 contemporary serotype M3 strains representing distinct genotypes and phenotypes. Serotype M3 strains are a single phylogenetic lineage. Strains from asymptomatic throat carriers were significantly less virulent for mice than sterile-site isolates and evolved to a less virulent phenotype by multiple genetic pathways. Strain persistence or extinction between epidemics was strongly associated with presence or absence, respectively, of the prophage encoding streptococcal pyrogenic exotoxin A. A serotype M3 clone significantly underrepresented among necrotizing fasciitis cases has a unique frameshift mutation that truncates MtsR, a transcriptional regulator controlling expression of genes encoding iron-acquisition proteins. Expression microarray analysis of this clone confirmed significant alteration in expression of genes encoding iron metabolism proteins. Our analysis provided unprecedented detail about the molecular anatomy of bacterial strain genotype-patient phenotype relationships.
Bocanegra-García, Virgilio; del Rayo Camacho-Corona, María; Ramírez-Cabrera, Mónica; Rivera, Gildardo; Garza-González, Elvira
Background Lower respiratory tract infections are a major cause of illness and death. Such infections are common in intensive care units (ICU) and their lethality persists despite advances in diagnosis, treatment and prevention. In Mexico, some plants are used in traditional medicine to treat respiratory diseases or ailments such as cough, bronchitis, tuberculosis and other infections. Medical knowledge derived from traditional societies has motivated searches for new bioactive molecules derived from plants that show potent activity against bacterial pathogens. Therefore, the aim of this study was to evaluate the effect of hexanic, chloroformic (CLO), methanolic (MET) and aqueous extracts from various plants used in Mexican traditional medicine on various microorganisms associated with respiratory disease. Methods thirty-five extracts prepared from nine plants used in Mexican traditional medicine for the treatment of respiratory infections were evaluated against 15 control bacterial species and clinical isolates. Results Both chloroformic (CLO) and methanolic (MET) extracts of Larrea tridentata were active against Methicillin-resistant S. aureus, B. subtilis and L. monocytogenes. A MET extract of L. tridentata was also active against S. aureus, S. pneumoniae, S. maltophilia, E. faecalis and H. influenzae and the CLO extract was active against A. baumannii. An Aqueous extract of M. acumitata and a MET extract of N. officinale were active against S. pneumoniae. CLO and MET extracts of L. tridentata were active against clinical isolates of S. aureus, S. pneumoniae and E. faecalis. Conclusion Overall, our results support the potential use of L. tridentata as a source of antibacterial compounds. PMID:19486533
Li, Laam; Mendis, Nilmini; Trigui, Hana; Oliver, James D.; Faucher, Sebastien P.
Many bacterial species have been found to exist in a viable but non-culturable (VBNC) state since its discovery in 1982. VBNC cells are characterized by a loss of culturability on routine agar, which impairs their detection by conventional plate count techniques. This leads to an underestimation of total viable cells in environmental or clinical samples, and thus poses a risk to public health. In this review, we present recent findings on the VBNC state of human bacterial pathogens. The characteristics of VBNC cells, including the similarities and differences to viable, culturable cells and dead cells, and different detection methods are discussed. Exposure to various stresses can induce the VBNC state, and VBNC cells may be resuscitated back to culturable cells under suitable stimuli. The conditions that trigger the induction of the VBNC state and resuscitation from it are summarized and the mechanisms underlying these two processes are discussed. Last but not least, the significance of VBNC cells and their potential influence on human health are also reviewed. PMID:24917854
Ostrowska, Kinga; Strzelczyk, Aleksandra; Różalski, Antoni; Stączek, Paweł
Urinary tract infections (UTI) are one of the common chronic and recurrent bacterial infections. Uropathogens which are able to form biofilm constitute a major etiological factor in UTI, especially among elder patients who are subject to long-term catheterization. It is caused by the capacity of the microorganisms for efficient and permanent colonization of tissues and also adhesion to diverse polymers used for urological catheter production such as propylene, polystyrene, silicone, polyvinyl chloride or silicone coated latex. Antibiotic therapy is the most common treatment for UTI. Fluoroquinolones, nitrofurans, beta-lactams, aminoglycosides, trimethoprim and sulfonamides are used predominantly. However, the biofilm due to its complex structure constitutes an effective barrier to the antibiotics used in the treatment of urinary tract infections. In addition, the growing number of multidrug resistant strains limits the usage of many of the currently available chemotherapeutic agents. Therefore, it seems important to search for new methods of treatment such as coating of catheters with non-pathogenic E. coli strains, the design of vaccines against fimbrial adhesive proteins of the bacterial cells or the use of bacteriophages.
Gillespie, Joseph J.; Wattam, Alice R.; Cammer, Stephen A.; Gabbard, Joseph L.; Shukla, Maulik P.; Dalay, Oral; Driscoll, Timothy; Hix, Deborah; Mane, Shrinivasrao P.; Mao, Chunhong; Nordberg, Eric K.; Scott, Mark; Schulman, Julie R.; Snyder, Eric E.; Sullivan, Daniel E.; Wang, Chunxia; Warren, Andrew; Williams, Kelly P.; Xue, Tian; Seung Yoo, Hyun; Zhang, Chengdong; Zhang, Yan; Will, Rebecca; Kenyon, Ronald W.; Sobral, Bruno W.
Funded by the National Institute of Allergy and Infectious Diseases, the Pathosystems Resource Integration Center (PATRIC) is a genomics-centric relational database and bioinformatics resource designed to assist scientists in infectious-disease research. Specifically, PATRIC provides scientists with (i) a comprehensive bacterial genomics database, (ii) a plethora of associated data relevant to genomic analysis, and (iii) an extensive suite of computational tools and platforms for bioinformatics analysis. While the primary aim of PATRIC is to advance the knowledge underlying the biology of human pathogens, all publicly available genome-scale data for bacteria are compiled and continually updated, thereby enabling comparative analyses to reveal the basis for differences between infectious free-living and commensal species. Herein we summarize the major features available at PATRIC, dividing the resources into two major categories: (i) organisms, genomes, and comparative genomics and (ii) recurrent integration of community-derived associated data. Additionally, we present two experimental designs typical of bacterial genomics research and report on the execution of both projects using only PATRIC data and tools. These applications encompass a broad range of the data and analysis tools available, illustrating practical uses of PATRIC for the biologist. Finally, a summary of PATRIC's outreach activities, collaborative endeavors, and future research directions is provided. PMID:21896772
Ruedl, C; Frühwirth, M; Wick, G; Wolf, H
We have investigated the local immune response of the BALB/c mouse respiratory tract after oral immunization with a bacterial lysate of seven common respiratory pathogens. After two immunization on five consecutive days, we examined the immunoglobulin (immunoglobulin G [IgG], IgM, and IgA) secretion rates of cells isolated from the lungs and compared them with those of spleen cells of orally immunized and nonimmunized animals by using a new test system based on time-resolved fluorescence. The procedure followed the principle of the classical ELISPOT test with nitrocellulose-bottomed microtiter plates, but europium (Eu3+)-linked streptavidin rather than enzyme-conjugated streptavidin was used, with the advantage of quantifying secreted immunoglobulins instead of detecting single antibody-secreting cells. Lymphocytes isolated from the lungs of treated animals revealed significant increases in total and antigen-specific IgA synthesis compared with the rates of the controls, whereas IgG and IgM production rates showed no remarkable differences. In addition, the sera of treated mice revealed higher antigen-specific IgA titers but not increased IgM and IgG levels. We conclude that priming the gut-associated lymphoid tissue with bacterial antigens of pneumotropic microorganisms can elicit an enhanced IgA response in a distant mucosal effector site, such as the respiratory tract, according to the concept of a common mucosa-associated immune system.
Javid, Ashkan; Zlotnikov, Nataliya; Pětrošová, Helena; Tang, Tian Tian; Zhang, Yang; Bansal, Anil K; Ebady, Rhodaba; Parikh, Maitry; Ahmed, Mijhgan; Sun, Chunxiang; Newbigging, Susan; Kim, Yae Ram; Santana Sosa, Marianna; Glogauer, Michael; Moriarty, Tara J
Insulin-insufficient type 1 diabetes is associated with attenuated bactericidal function of neutrophils, which are key mediators of innate immune responses to microbes as well as pathological inflammatory processes. Neutrophils are central to immune responses to the Lyme pathogen Borrelia burgdorferi. The effect of hyperglycemia on host susceptibility to and outcomes of B. burgdorferi infection has not been examined. The present study investigated the impact of sustained obesity-independent hyperglycemia in mice on bacterial clearance, inflammatory pathology and neutrophil responses to B. burgdorferi. Hyperglycemia was associated with reduced arthritis incidence but more widespread tissue colonization and reduced clearance of bacterial DNA in multiple tissues including brain, heart, liver, lung and knee joint. B. burgdorferi uptake and killing were impaired in neutrophils isolated from hyperglycemic mice. Thus, attenuated neutrophil function in insulin-insufficient hyperglycemia was associated with reduced B. burgdorferi clearance in target organs. These data suggest that investigating the effects of comorbid conditions such as diabetes on outcomes of B. burgdorferi infections in humans may be warranted.
Wang, Jinghua; Xu, Haiyang; Wang, Dunwei; Li, Mingxian
A large number of population in both developing and developed countries are affected by bronchitis, among all the factors, bacterial infection was considered as a critical cause of acute exacerbations of chronic bronchitis. Although several anti-bacterial agents were proved to have the effect of alleviating bronchitis, their relative efficacies and potential side effects remained not clear. We are keen to compare the pathogen eradication rate and safety of anti-bacterial agents for bronchitis. Relevant studies were searched in multiple sources and data were extracted from eligible studies. Then conventional meta-analysis and network meta-analysis (NMA) were conducted to determine the relative efficacy and safety of bronchitis medications. The efficacy of bronchitis medications was determined by using the outcome of pathogen eradication, including total pathogen eradication, pathogen eradication of Haemophilus influenzae, pathogen eradication of Moraxella catarrhalis, and pathogen eradication of Streptococcus pneumoniae. In addition, safety was assessed by using the outcome of adverse effects and diarrhoea. A 27 RCTs with 9,414 participants were included in the study. Among the medications, gatifloxacin and moxifloxacin exhibited better performance than clarithromycin with respect to pathogen eradication of H. influenzae (OR = 21.37, CI: 1.22-541.28; OR = 7.43, CI: 1.79-30.50). Clarithromycin, gemifloxacin, levofloxacin, moxifloxacin, and telithromycin appeared to be more preferable than amoxicillin + clavulanate and azithromycin with respect to diarrhoea (all OR <1). The surface under the cumulative ranking curve (SUCRA) results suggested that gemifloxacin and levofloxacin had a relatively high ranking in total pathogen eradication, whereas amoxicillin + clavulanate and azithromycin exhibited relatively lower ranking with respect to adverse effects and diarrhoea. Gemifloxacin and levofloxacin are more preferable than others for lowering respiratory
Ishii, Satoshi; Yan, Tao; Shively, Dawn A.; Byappanahalli, Muruleedhara N.; Whitman, Richard L.; Sadowsky, Michael J.
Cladophora glomerata, a macrophytic green alga, is commonly found in the Great Lakes, and significant accumulations occur along shorelines during the summer months. Recently, Cladophora has been shown to harbor high densities of the fecal indicator bacteria Escherichia coli and enterococci. Cladophora may also harbor human pathogens; however, until now, no studies to address this question have been performed. In the present study, we determined whether attached Cladophora, obtained from the Lake Michigan and Burns Ditch (Little Calumet River, Indiana) sides of a breakwater during the summers of 2004 and 2005, harbored the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC), Salmonella, Shigella, and Campylobacter. The presence of potential pathogens and numbers of organisms were determined by using cultural methods and by using conventional PCR, most-probable-number PCR (MPN-PCR), and quantitative PCR (QPCR) performed with genus- and toxin-specific primers and probes. While Shigella and STEC were detected in 100% and 25%, respectively, of the algal samples obtained near Burns Ditch in 2004, the same pathogens were not detected in samples collected in 2005. MPN-PCR and QPCR allowed enumeration of Salmonella in 40 to 80% of the ditch- and lakeside samples, respectively, and the densities were up to 1.6 × 103 cells per g Cladophora. Similarly, these PCR methods allowed enumeration of up to 5.4 × 102 Campylobacter cells/g Cladophora in 60 to 100% of lake- and ditchside samples. The Campylobacter densities were significantly higher (P < 0.05) in the lakeside Cladophora samples than in the ditchside Cladophora samples. DNA fingerprint analyses indicated that genotypically identical Salmonella isolates were associated with geographically and temporally distinct Cladophora samples. However, Campylobacter isolates were genetically diverse. Since animal hosts are thought to be the primary habitat for Campylobacter and Salmonella species, our results suggest
Ishii, Satoshi; Yan, Tao; Shively, Dawn A; Byappanahalli, Muruleedhara N; Whitman, Richard L; Sadowsky, Michael J
Cladophora glomerata, a macrophytic green alga, is commonly found in the Great Lakes, and significant accumulations occur along shorelines during the summer months. Recently, Cladophora has been shown to harbor high densities of the fecal indicator bacteria Escherichia coli and enterococci. Cladophora may also harbor human pathogens; however, until now, no studies to address this question have been performed. In the present study, we determined whether attached Cladophora, obtained from the Lake Michigan and Burns Ditch (Little Calumet River, Indiana) sides of a breakwater during the summers of 2004 and 2005, harbored the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC), Salmonella, Shigella, and Campylobacter. The presence of potential pathogens and numbers of organisms were determined by using cultural methods and by using conventional PCR, most-probable-number PCR (MPN-PCR), and quantitative PCR (QPCR) performed with genus- and toxin-specific primers and probes. While Shigella and STEC were detected in 100% and 25%, respectively, of the algal samples obtained near Burns Ditch in 2004, the same pathogens were not detected in samples collected in 2005. MPN-PCR and QPCR allowed enumeration of Salmonella in 40 to 80% of the ditch- and lakeside samples, respectively, and the densities were up to 1.6 x 10(3) cells per g Cladophora. Similarly, these PCR methods allowed enumeration of up to 5.4 x 10(2) Campylobacter cells/g Cladophora in 60 to 100% of lake- and ditchside samples. The Campylobacter densities were significantly higher (P < 0.05) in the lakeside Cladophora samples than in the ditchside Cladophora samples. DNA fingerprint analyses indicated that genotypically identical Salmonella isolates were associated with geographically and temporally distinct Cladophora samples. However, Campylobacter isolates were genetically diverse. Since animal hosts are thought to be the primary habitat for Campylobacter and Salmonella species, our results suggest
Psoter, Kevin J; De Roos, Anneclaire J; Wakefield, Jon; Mayer, Jonathan D; Rosenfeld, Margaret
Seasonal variations are often observed for respiratory tract infections; however, limited information is available regarding seasonal patterns of acquisition of common cystic fibrosis (CF)-related respiratory pathogens. We previously reported differential seasonal acquisition of Pseudomonas aeruginosa in young children with CF and no such variation for methicillin-susceptible Staphylococcus aureus acquisition. The purpose of this study was to describe and compare the seasonal incidence of acquisition of other respiratory bacterial pathogens in young children with CF. We conducted a retrospective study to describe and compare the seasonal incidence of methicillin-resistant Staphylococcus aureus (MRSA), Stenotrophomonas maltophilia, Achromobacter xylosoxidans, and Haemophilus influenzae acquisition in young CF patients residing in the U.S. using the Cystic Fibrosis Foundation National Patient Registry, 2003-2009. Log-linear overdispersed Poisson regression was used to evaluate seasonal acquisition of each of these pathogens. A total of 4552 children met inclusion criteria. During follow-up 910 (20%), 1161 (26%), 228 (5%), and 2148 (47%) children acquired MRSA, S. maltophilia, A. xylosoxidans and H. influenzae, respectively. Compared to winter season, MRSA was less frequently acquired in spring (Incidence Rate Ratio [IRR]: 0.79; 95% Confidence Interval [CI]: 0.65, 0.96) and summer (IRR: 0.69; 95% CI: 0.57, 0.84) seasons. Similarly, a lower rate of A. xylosoxidans acquisition was observed in spring (IRR: 0.59; 95% CI: 0.39, 0.89). For H. influenzae, summer (IRR: 0.88; 95% CI: 0.78, 0.99) and autumn (IRR: 0.78; 95% CI: 0.69, 0.88) seasons were associated with lower acquisition rates compared to winter. No seasonal variation was observed for S. maltophilia acquisition. Acquisition of CF-related respiratory pathogens displays seasonal variation in young children with CF, with the highest rate of acquisition for most pathogens occurring in the winter. Investigation of
Ishii, S.; Yan, T.; Shively, D.A.; Byappanahalli, M.N.; Whitman, R.L.; Sadowsky, M.J.
Cladophora glomerata, a macrophytic green alga, is commonly found in the Great Lakes, and significant accumulations occur along shorelines during the summer months. Recently, Cladophora has been shown to harbor high densities of the fecal indicator bacteria Escherichia coli and enterococci. Cladophora may also harbor human pathogens; however, until now, no studies to address this question have been performed. In the present study, we determined whether attachedCladophora, obtained from the Lake Michigan and Burns Ditch (Little Calumet River, Indiana) sides of a breakwater during the summers of 2004 and 2005, harbored the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC),Salmonella, Shigella, and Campylobacter. The presence of potential pathogens and numbers of organisms were determined by using cultural methods and by using conventional PCR, most-probable-number PCR (MPN-PCR), and quantitative PCR (QPCR) performed with genus- and toxin-specific primers and probes. WhileShigella and STEC were detected in 100% and 25%, respectively, of the algal samples obtained near Burns Ditch in 2004, the same pathogens were not detected in samples collected in 2005. MPN-PCR and QPCR allowed enumeration of Salmonella in 40 to 80% of the ditch- and lakeside samples, respectively, and the densities were up to 1.6 × 103 cells per g Cladophora. Similarly, these PCR methods allowed enumeration of up to 5.4 × 102 Campylobacter cells/gCladophora in 60 to 100% of lake- and ditchside samples. The Campylobacterdensities were significantly higher (P < 0.05) in the lakeside Cladophora samples than in the ditchside Cladophora samples. DNA fingerprint analyses indicated that genotypically identical Salmonella isolates were associated with geographically and temporally distinct Cladophora samples. However, Campylobacter isolates were genetically diverse. Since animal hosts are thought to be the primary habitat for
Witek, Karolina; Nasim, Muhammad Jawad; Bischoff, Markus; Gaupp, Rosmarie; Arsenyan, Pavel; Vasiljeva, Jelena; Marć, Małgorzata Anna; Olejarz, Agnieszka; Latacz, Gniewomir; Kieć-Kononowicz, Katarzyna; Handzlik, Jadwiga; Jacob, Claus
In view of the pressing need to identify new antibacterial agents able to combat multidrug-resistant bacteria, we investigated a series of fused selenazolinium derivatives ( 1 - 8 ) regarding their in vitro antimicrobial activities against 25 ESKAPE-pathogen strains. Ebselen was used as reference compound. Most of the selenocompounds demonstrated an excellent in vitro activity against all S. aureus strains, with activities comparable to or even exceeding the one of ebselen. In contrast to ebselen, some selenazolinium derivatives ( 1 , 3 , and 7 ) even displayed significant actions against all Gram-negative pathogens tested. The 3-bromo-2-(1-hydroxy-1-methylethyl)[1,2]selenazolo[2,3- a ]pyridinium chloride ( 1 ) was particularly active (minimum inhibitory concentrations, MICs: 0.31-1.24 µg/mL for MRSA, and 0.31-2.48 µg/mL for Gram-negative bacteria) and devoid of any significant mutagenicity in the Ames assay. Our preliminary mechanistic studies in cell culture indicated that their mode of action is likely to be associated with an alteration of intracellular levels of glutathione and cysteine thiols of different proteins in the bacterial cells, hence supporting the idea that such compounds interact with the intracellular thiolstat. This alteration of pivotal cysteine residues is most likely the result of a direct or catalytic oxidative modification of such residues by the highly reactive selenium species (RSeS) employed.
Oster, Ryan J; Wijesinghe, Rasanthi U; Haack, Sheridan K; Fogarty, Lisa R; Tucker, Taaja R; Riley, Stephen C
Quantitative assessment of bacterial pathogens, their geographic variability, and distribution in various matrices at Great Lakes beaches are limited. Quantitative PCR (qPCR) was used to test for genes from E. coli O157:H7 (eaeO157), shiga-toxin producing E. coli (stx2), Campylobacter jejuni (mapA), Shigella spp. (ipaH), and a Salmonella enterica-specific (SE) DNA sequence at seven Great Lakes beaches, in algae, water, and sediment. Overall, detection frequencies were mapA>stx2>ipaH>SE>eaeO157. Results were highly variable among beaches and matrices; some correlations with environmental conditions were observed for mapA, stx2, and ipaH detections. Beach seasonal mean mapA abundance in water was correlated with beach seasonal mean log10 E. coli concentration. At one beach, stx2 gene abundance was positively correlated with concurrent daily E. coli concentrations. Concentration distributions for stx2, ipaH, and mapA within algae, sediment, and water were statistically different (Non-Detect and Data Analysis in R). Assuming 10, 50, or 100% of gene copies represented viable and presumably infective cells, a quantitative microbial risk assessment tool developed by Michigan State University indicated a moderate probability of illness for Campylobacter jejuni at the study beaches, especially where recreational water quality criteria were exceeded. Pathogen gene quantification may be useful for beach water quality management.
Uchida, Yoshiko; Matsubara, Kousaku; Wada, Tamaki; Oishi, Kazunori; Morio, Tomohiro; Takada, Hidetoshi; Iwata, Aya; Yura, Kazuo; Kamimura, Katsunori; Nigami, Hiroyuki; Fukaya, Takashi
Isolated congenital asplenia (ICA) is a rare condition at risk for overwhelming infection. When complicated by invasive infection, the mortality remains high, at greater than 60%. We describe a girl with ICA who developed recurrent meningitis by three different pathogens. The first, meningitis by Escherichia coli, occurred 4 days after premature birth. The other two pathogens were serotype 6B Streptococcus pneumoniae and Haemophilus influenzae type b (Hib), at 18 and 25 months of age, respectively. The patient was successfully treated with prompt antimicrobial therapy in all episodes. Serum anti-polyribosylribitol phosphate (PRP) and anti-6B-type pneumococcal antibodies were below the levels for protective activity after natural infections. Although anti-PRP antibody was significantly increased after Hib vaccination, two (6B and 19F) of seven serotype-specific pneumococcal antibodies were not elevated to protective levels after the second 7-valent pneumococcal conjugate vaccine (PCV7). We, therefore, added a third PCV7. To our knowledge, this is the first neonatal ICA patient with invasive infection and the first case of bacterial meningitis occurring three times. Our findings indicate that monitoring of immune responses after natural infections and vaccinations, and reevaluations of vaccine schedule, are important for ICA patients to prevent subsequent invasive infections.
Peng, Mengfei; Bitsko, Elizabeth; Biswas, Debabrata
Various compounds found in peanut (Arachis hypogaea) have been shown to provide multiple benefits to human health and may influence the growth of a broad range of gut bacteria. In this study, we investigated the effects of peanut white kernel and peanut skin on 3 strains of Lactobacillus and 3 major foodborne enteric bacterial pathogens. Significant (P < 0.05) growth stimulation of Lactobacillus casei and Lactobacillus rhamnosus was observed in the presence of 0.5% peanut flour (PF) made from peanut white kernel, whereas 0.5% peanut skin extract (PSE) exerted the inhibitory effect on the growth of these beneficial microbes. We also found that within 72 h, PF inhibited growth of enterohemorrhagic Escherichia coli O157:H7 (EHEC), while PSE significantly (P < 0.05) inhibited Listeria monocytogenes but promoted the growth of both EHEC and Salmonella Typhimurium. The cell adhesion and invasion abilities of 3 pathogens to the host cells were also significantly (P < 0.05) reduced by 0.5% PF and 0.5% PSE. These results suggest that peanut white kernel might assist in improving human gut flora as well as reducing EHEC, whereas the beneficial effects of peanut skins require further research and investigation. © 2015 Institute of Food Technologists®
Nho, Seong Won; Hikima, Jun-ichi; Cha, In Seok; Park, Seong Bin; Jang, Ho Bin; del Castillo, Carmelo S.; Kondo, Hidehiro; Hirono, Ikuo; Aoki, Takashi; Jung, Tae Sung
Although Streptococcus parauberis is known as a bacterial pathogen associated with bovine udder mastitis, it has recently become one of the major causative agents of olive flounder (Paralichthys olivaceus) streptococcosis in northeast Asia, causing massive mortality resulting in severe economic losses. S. parauberis contains two serotypes, and it is likely that capsular polysaccharide antigens serve to differentiate the serotypes. In the present study, the complete genome sequence of S. parauberis (serotype I) was determined using the GS-FLX system to investigate its phylogeny, virulence factors, and antigenic proteins. S. parauberis possesses a single chromosome of 2,143,887 bp containing 1,868 predicted coding sequences (CDSs), with an average GC content of 35.6%. Whole-genome dot plot analysis and phylogenetic analysis of a 60-kDa chaperonin-encoding gene and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-encoding gene showed that the strain was evolutionarily closely related to Streptococcus uberis. S. parauberis antigenic proteins were analyzed using an immunoproteomic technique. Twenty-one antigenic protein spots were identified in S. parauberis, by reaction with an antiserum obtained from S. parauberis-challenged olive flounder. This work provides the foundation needed to understand more clearly the relationship between pathogen and host and develops new approaches toward prophylactic and therapeutic strategies to deal with streptococcosis in fish. The work also provides a better understanding of the physiology and evolution of a significant representative of the Streptococcaceae. PMID:21531805
Dutta, Bhabesh; Gitaitis, Ronald; Smith, Samuel; Langston, David
The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1×106 colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized
Song, Hong-Yan; Qiu, Bao-Feng; Liu, Chun; Zhu, Shun-Xing; Wang, Sheng-Cun; Miao, Jin; Jing, Jing; Shao, Yi-Xiang
The clone library method using PCR amplification of the 16S ribosomal RNA (rRNA) gene was used to identify pathogens from corneal scrapings of C57BL/6-corneal opacity (B6-Co) mice with bacterial keratitis. All 10 samples from the eyes with bacterial keratitis showed positive PCR results. All 10 samples from the normal cornea showed negative PCR results. In all 10 PCR-positive samples, the predominant and second most predominant species accounted for 20.9 to 40.6% and 14.7 to 26.1%, respectively, of each clone library. The predominant species were Staphylococcus lentus, Pseudomonas aeruginosa, and Staphylococcus epidermidis. The microbiota analysis detected a diverse group of microbiota in the eyes of B6-Co mice with bacterial keratitis and showed that the causative pathogens could be determined based on percentages of bacterial species in the clone libraries. The bacterial species detected in this study were mostly in accordance with results of studies on clinical bacterial keratitis in human eyes. Based on the results of our previous studies and this study, the B6-Co mouse should be considered a favorable model for studying bacterial keratitis. PMID:25312507
Starliper, Clifford E.; Cipriano, R.C.; Bruckner, A.W.; Shchelkunov, I.S.
Unionid mussels are recognized as important contributors to healthy aquatic ecosystems, as well as bioindicators of environmental perturbations. Because they are sedentary, filter feeding animals and require hosts (i.e., fishes) to transform embryonic glochidia, mussels are susceptible to direct adverse environmental parameters, and indirect parameters that restrict the timely presence of the host(s). Their numbers have declined in recent decades to a point that this fauna is regarded as one of the most imperiled in North America. The most significant threat to populations of native unionids in recent years has been the introduction and spread of zebra mussels Dreissena polymorpha. Many federal and state agencies, and private interests are now engaged in mussel conservation efforts, including collecting selected imperiled species from impacted rivers and lakes and propagating them at refuges for future population augmentations. One essential consideration with mussel propagation and their intensive culture at refugia is the prevention of pathogen introductions and control of diseases. Currently, there are few reports of etiological agents causing diseases among freshwater mussels; however, because of increased observations of mussel die-offs in conjunction with transfers of live animals between natural waters and refugia, disease problems can be anticipated to emerge. This review summarizes research to develop bacterial isolation techniques, study pathogen transmission between fish and mussels, identify causes of seasonal mussel die-offs, and develop non-destructive methods for pathogen detection. These efforts were done to develop disease preventative techniques for use by resource managers to avoid potential large-scale disease problems in restoration and population augmentation efforts among imperiled populations.
Lu, Xin; Zhang, Xu-Xiang; Wang, Zhu; Huang, Kailong; Wang, Yuan; Liang, Weigang; Tan, Yunfei; Liu, Bo; Tang, Junying
This study used 454 pyrosequencing, Illumina high-throughput sequencing and metagenomic analysis to investigate bacterial pathogens and their potential virulence in a sewage treatment plant (STP) applying both conventional and advanced treatment processes. Pyrosequencing and Illumina sequencing consistently demonstrated that Arcobacter genus occupied over 43.42% of total abundance of potential pathogens in the STP. At species level, potential pathogens Arcobacter butzleri, Aeromonas hydrophila and Klebsiella pneumonia dominated in raw sewage, which was also confirmed by quantitative real time PCR. Illumina sequencing also revealed prevalence of various types of pathogenicity islands and virulence proteins in the STP. Most of the potential pathogens and virulence factors were eliminated in the STP, and the removal efficiency mainly depended on oxidation ditch. Compared with sand filtration, magnetic resin seemed to have higher removals in most of the potential pathogens and virulence factors. However, presence of the residual A. butzleri in the final effluent still deserves more concerns. The findings indicate that sewage acts as an important source of environmental pathogens, but STPs can effectively control their spread in the environment. Joint use of the high-throughput sequencing technologies is considered a reliable method for deep and comprehensive overview of environmental bacterial virulence. PMID:25938416
This study examined persistence and decay of bacterial pathogens, fecal indicator bacteria, and emerging real-time quantitative PCR (qPCR) genetic markers for rapid detection of fecal pollution in manre-amended agricultural soils. Known concentrations of transformed green fluore...
This study examined persistence and decay of bacterial pathogens, fecal indicator bacteria (FIB), and emerging real-time quantitative PCR (qPCR) genetic markers for rapid detection of fecal pollution in manure-amended agricultural soils. Known concentrations of transformed green...
Huy, Nguyen Tien; Hang, Le Thi Thuy; Boamah, Daniel; Lan, Nguyen Thi Phuong; Van Thanh, Phan; Watanabe, Kiwao; Huong, Vu Thi Thu; Kikuchi, Mihoko; Ariyoshi, Koya; Morita, Kouichi; Hirayama, Kenji
Several loop-mediated isothermal amplification (LAMP) assays have been developed to detect common causative pathogens of bacterial meningitis (BM). However, no LAMP assay is reported to detect Streptococcus agalactiae and Streptococcus suis, which are also among common pathogens of BM. Moreover, it is laborious and expensive by performing multiple reactions for each sample to detect bacterial pathogen. Thus, we aimed to design and develop a single-tube LAMP assay capable of detecting multiple bacterial species, based on the nucleotide sequences of the 16S rRNA genes of the bacteria. The nucleotide sequences of the 16S rRNA genes of main pathogens involved in BM were aligned to identify conserved regions, which were further used to design broad range specific LAMP assay primers. We successfully designed a set of broad range specific LAMP assay primers for simultaneous detection of four species including Staphylococcus aureus, Streptococcus pneumoniae, S. suis and S. agalactiae. The broad range LAMP assay was highly specific without cross-reactivity with other bacteria including Haemophilus influenzae, Neisseria meningitidis and Escherichia coli. The sensitivity of our LAMP assay was 100-1000 times higher compared with the conventional PCR assay. The bacterial species could be identified after digestion of the LAMP products with restriction endonuclease DdeI and HaeIII. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
Question: In the absence of antibiotic use within pastured poultry production, what are potential environmental variables that drive the antimicrobial sensitivity patterns of bacterial foodborne pathogens isolated from these flocks? Purpose: The objective of this study is to examine environmental f...
Krusor, Colin; Smith, Woutrina A.; Tinker, M. Tim; Silver, Mary; Conrad, Patricia A.; Shapiro, Karen
The parasite Toxoplasma gondii is an environmentally persistent pathogen that can cause fatal disease in humans, terrestrial warm-blooded animals and aquatic mammals. Although an association between T. gondii exposure and prey specialization on marine snails was identified in threatened California sea otters, the ability of kelp-dwelling snails to transmit terrestrially derived pathogens has not been previously investigated. The objective of this study was to measure concentration and retention of T. gondii by marine snails in laboratory aquaria, and to test for natural T. gondii contamination in field-collected snails. Following exposure to T. gondii-containing seawater, oocysts were detected by microscopy in snail faeces and tissues for 10 and 3 days respectively. Nested polymerase chain reaction was also applied as a method for confirming putative T. gondii oocysts detected in snail faeces and tissues by microscopy. Toxoplasma gondiiwas not detected in field-collected snails. Results suggest that turban snails are competent transport hosts for T. gondii. By concentrating oocysts in faecal pellets, snails may facilitate entry of T. gondii into the nearshore marine food web. This novel mechanism also represents a general pathway by which marine transmission of terrestrially derived microorganisms can be mediated via pathogen concentration and retention by benthic invertebrates.
Pathogenic species of Leptospira cause leptospirosis, a bacterial zoonotic disease with a global distribution affecting over one million people annually. Reservoir hosts of leptospirosis, including rodents, dogs and cattle, exhibit little to no signs of disease but shed large numbers of organisms in...
Grewal, Sukhbir K.; Rajeev, Sreekumari; Sreevatsan, Srinand; Michel, Frederick C.
Livestock manures contain numerous microorganisms which can infect humans and/or animals, such as Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and Mycobacterium avium subsp. paratuberculosis (Mycobacterium paratuberculosis). The effects of commonly used manure treatments on the persistence of these pathogens have rarely been compared. The objective of this study was to compare the persistence of artificially inoculated M. paratuberculosis, as well as other naturally occurring pathogens, during the treatment of dairy manure under conditions that simulate three commonly used manure management methods: thermophilic composting at 55°C, manure packing at 25°C (or low-temperature composting), and liquid lagoon storage. Straw and sawdust amendments used for composting and packing were also compared. Manure was obtained from a large Ohio free-stall dairy herd and was inoculated with M. paratuberculosis at 106 CFU/g in the final mixes. For compost and pack treatments, this manure was amended with sawdust or straw to provide an optimal moisture content (60%) for composting for 56 days. To simulate liquid storage, water was added to the manure (to simulate liquid flushing and storage) and the slurry was placed in triplicate covered 4-liter Erlenmeyer flasks, incubated under ambient conditions for 175 days. The treatments were sampled on days 0, 3, 7, 14, 28, and 56 for the detection of pathogens. The persistence of M. paratuberculosis was also assessed by a PCR hybridization assay. After 56 days of composting, from 45 to 60% of the carbon in the compost treatments was converted to CO2, while no significant change in carbon content was observed in the liquid slurry. Escherichia coli, Salmonella, and Listeria were all detected in the manure and all of the treatments on day 0. After 3 days of composting at 55°C, none of these organisms were detectable. In liquid manure and pack treatments, some of these microorganisms were detectable up to 28 days. M
Bhuyan, Golam Sarower; Hossain, Mohammad Amir; Sarker, Suprovath Kumar; Rahat, Asifuzzaman; Islam, Md Tarikul; Haque, Tanjina Noor; Begum, Noorjahan; Qadri, Syeda Kashfi; Muraduzzaman, A. K. M.; Islam, Nafisa Nawal; Islam, Mohammad Sazzadul; Sultana, Nusrat; Jony, Manjur Hossain Khan; Khanam, Farhana; Mowla, Golam; Matin, Abdul; Begum, Firoza; Shirin, Tahmina; Ahmed, Dilruba; Saha, Narayan; Qadri, Firdausi
The study aimed to examine for the first time the spectra of viral and bacterial pathogens along with the antibiotic susceptibility of the isolated bacteria in under-5 children with acute respiratory infections (ARIs) in hospital settings of Dhaka, Bangladesh. Nasal swabs were collected from 200 under-five children hospitalized with clinical signs of ARIs. Nasal swabs from 30 asymptomatic children were also collected. Screening of viral pathogens targeted ten respiratory viruses using RT-qPCR. Bacterial pathogens were identified by bacteriological culture methods and antimicrobial susceptibility of the isolates was determined following CLSI guidelines. About 82.5% (n = 165) of specimens were positive for pathogens. Of 165 infected cases, 3% (n = 6) had only single bacterial pathogens, whereas 43.5% (n = 87) cases had only single viral pathogens. The remaining 36% (n = 72) cases had coinfections. In symptomatic cases, human rhinovirus was detected as the predominant virus (31.5%), followed by RSV (31%), HMPV (13%), HBoV (11%), HPIV-3 (10.5%), and adenovirus (7%). Streptococcus pneumoniae was the most frequently isolated bacterial pathogen (9%), whereas Klebsiella pneumaniae, Streptococcus spp., Enterobacter agglomerans, and Haemophilus influenzae were 5.5%, 5%, 2%, and 1.5%, respectively. Of 15 multidrug-resistant bacteria, a Klebsiella pneumoniae isolate and an Enterobacter agglomerans isolate exhibited resistance against more than 10 different antibiotics. Both ARI incidence and predominant pathogen detection rates were higher during post-monsoon and winter, peaking in September. Pathogen detection rates and coinfection incidence in less than 1-year group were significantly higher (P = 0.0034 and 0.049, respectively) than in 1–5 years age group. Pathogen detection rate (43%) in asymptomatic cases was significantly lower compared to symptomatic group (P<0.0001). Human rhinovirus, HPIV-3, adenovirus, Streptococcus pneumonia, and Klebsiella pneumaniae had
Mayers, Teaghan J.; Bramucci, Anna R.; Yakimovich, Kurt M.; Case, Rebecca J.
recently been shown to have acquired resistance against EhVs at elevated temperature, bacterial pathogens with temperature-dependent virulence, such as R11, may become much more important in the ecology of E. huxleyi in a warming climate. PMID:27379036
Mayers, Teaghan J; Bramucci, Anna R; Yakimovich, Kurt M; Case, Rebecca J
shown to have acquired resistance against EhVs at elevated temperature, bacterial pathogens with temperature-dependent virulence, such as R11, may become much more important in the ecology of E. huxleyi in a warming climate.
As part of a trend toward healthy convenience foods, ready-to-eat (RTE) mixed-ingredient salads have become popular products among consumers. A mixed-ingredient salad contains combinations of raw ( e.g . leafy vegetables and tomatoes) and processed ( e.g . chicken, salmon, ham, pasta and couscous) ingredients. Contamination of leafy vegetables can occur during any step in the production chain and, since there is no step that kills pathogens, a completely safe final product can never be guaranteed. Meat ingredients, for example poultry meat and ham, are generally heat-treated before preparation, but may be contaminated after this treatment, e.g . when diced or sliced. When several ingredients are mixed together, cross-contamination may occur. Preparation of mixed-ingredient salads requires human handling, which presents an additional risk of bacterial contamination. With high-protein ingredients, e.g . cooked meat, the mixed-ingredient salad represents an excellent substrate for bacterial growth. This article reviews current knowledge regarding human bacterial pathogen prevalence in mixed-ingredient salads and the potential for pathogen growth in this product during storage.
ABSTRACT As part of a trend toward healthy convenience foods, ready-to-eat (RTE) mixed-ingredient salads have become popular products among consumers. A mixed-ingredient salad contains combinations of raw (e.g. leafy vegetables and tomatoes) and processed (e.g. chicken, salmon, ham, pasta and couscous) ingredients. Contamination of leafy vegetables can occur during any step in the production chain and, since there is no step that kills pathogens, a completely safe final product can never be guaranteed. Meat ingredients, for example poultry meat and ham, are generally heat-treated before preparation, but may be contaminated after this treatment, e.g. when diced or sliced. When several ingredients are mixed together, cross-contamination may occur. Preparation of mixed-ingredient salads requires human handling, which presents an additional risk of bacterial contamination. With high-protein ingredients, e.g. cooked meat, the mixed-ingredient salad represents an excellent substrate for bacterial growth. This article reviews current knowledge regarding human bacterial pathogen prevalence in mixed-ingredient salads and the potential for pathogen growth in this product during storage. PMID:29230273
Narusaka, Mari; Narusaka, Yoshihiro
Plant activators activate systemic acquired resistance-like defense responses or induced systemic resistance, and thus protect plants from pathogens. We screened a chemical library composed of structurally diverse small molecules. We isolated six plant immune-inducing thienopyrimidine-type compounds and their analogous compounds. It was observed that the core structure of thienopyrimidine plays a role in induced resistance in plants. Furthermore, we highlight the protective effect of thienopyrimidine-type compounds against both hemibiotrophic fungal pathogen, Colletotrichum higginsianum, and bacterial pathogen, Pseudomonas syringae pv. maculicola, in Arabidopsis thaliana. We suggest that thienopyrimidine-type compounds could be potential lead compounds as novel plant activators, and can be useful and effective agrochemicals against various plant diseases.
Bhuiyan, Mejbah Uddin; Snelling, Thomas L; West, Rachel; Lang, Jurissa; Rahman, Tasmina; Borland, Meredith L; Thornton, Ruth; Kirkham, Lea-Ann; Sikazwe, Chisha; Martin, Andrew C; Richmond, Peter C; Smith, David W; Jaffe, Adam; Blyth, Christopher C
Introduction Pneumonia is the leading cause of childhood morbidity and mortality globally. Introduction of the conjugate Haemophilus influenzae B and multivalent pneumococcal vaccines in developed countries including Australia has significantly reduced the overall burden of bacterial pneumonia. With the availability of molecular diagnostics, viruses are frequently detected in children with pneumonia either as primary pathogens or predispose to secondary bacterial infection. Many respiratory pathogens that are known to cause pneumonia are also identified in asymptomatic children, so the true contribution of these pathogens to childhood community-acquired pneumonia (CAP) remains unclear. Since the introduction of pneumococcal vaccines, very few comprehensive studies from developed countries have attempted to determine the bacterial and viral aetiology of pneumonia. We aim to determine the contribution of bacteria and viruses to childhood CAP to inform further development of effective diagnosis, treatment and preventive strategies. Methods and analysis We are conducting a prospective case–control study (PneumoWA) where cases are children with radiologically confirmed pneumonia admitted to Princess Margaret Hospital for Children (PMH) and controls are healthy children identified from PMH outpatient clinics and from local community immunisation clinics. The case–control ratio is 1:1 with 250 children to be recruited in each arm. Nasopharyngeal swabs are collected from both cases and controls to detect the presence of viruses and bacteria by PCR; pathogen load will be assessed by quantitative PCR. The prevalence of pathogens detected in cases and controls will be compared, the OR of detection and population attributable fraction to CAP for each pathogen will be determined; relationships between pathogen load and disease status and severity will be explored. Ethics and dissemination This study has been approved by the human research ethics committees of PMH, Perth
Marty, Loïc; Vigouroux, Armelle; Aumont-Nicaise, Magali; Dessaux, Yves; Faure, Denis; Moréra, Solange
Agrobacterium tumefaciens pathogens genetically modify their host plants to drive the synthesis of opines in plant tumors. Opines are either sugar phosphodiesters or the products of condensed amino acids with ketoacids or sugars. They are Agrobacterium nutrients and imported into the bacterial cell via periplasmic-binding proteins (PBPs) and ABC-transporters. Mannopine, an opine from the mannityl-opine family, is synthesized from an intermediate named deoxy-fructosyl-glutamine (DFG), which is also an opine and abundant Amadori compound (a name used for any derivative of aminodeoxysugars) present in decaying plant materials. The PBP MotA is responsible for mannopine import in mannopine-assimilating agrobacteria. In the nopaline-opine type agrobacteria strain, SocA protein was proposed as a putative mannopine binding PBP, and AttC protein was annotated as a mannopine binding-like PBP. Structural data on mannityl-opine-PBP complexes is currently lacking. By combining affinity data with analysis of seven x-ray structures at high resolution, we investigated the molecular basis of MotA, SocA, and AttC interactions with mannopine and its DFG precursor. Our work demonstrates that AttC is not a mannopine-binding protein and reveals a specific binding pocket for DFG in SocA with an affinity in nanomolar range. Hence, mannopine would not be imported into nopaline-type agrobacteria strains. In contrast, MotA binds both mannopine and DFG. We thus defined one mannopine and two DFG binding signatures. Unlike mannopine-PBPs, selective DFG-PBPs are present in a wide diversity of bacteria, including Actinobacteria, α-,β-, and γ-proteobacteria, revealing a common role of this Amadori compound in pathogenic, symbiotic, and opportunistic bacteria. PMID:27609514
Forsythe, Stephen J; Dickins, Benjamin; Jolley, Keith A
Following the association of Cronobacter spp. to several publicized fatal outbreaks in neonatal intensive care units of meningitis and necrotising enterocolitis, the World Health Organization (WHO) in 2004 requested the establishment of a molecular typing scheme to enable the international control of the organism. This paper presents the application of Next Generation Sequencing (NGS) to Cronobacter which has led to the establishment of the Cronobacter PubMLST genome and sequence definition database (http://pubmlst.org/cronobacter/) containing over 1000 isolates with metadata along with the recognition of specific clonal lineages linked to neonatal meningitis and adult infections Whole genome sequencing and multilocus sequence typing (MLST) has supports the formal recognition of the genus Cronobacter composed of seven species to replace the former single species Enterobacter sakazakii. Applying the 7-loci MLST scheme to 1007 strains revealed 298 definable sequence types, yet only C. sakazakii clonal complex 4 (CC4) was principally associated with neonatal meningitis. This clonal lineage has been confirmed using ribosomal-MLST (51-loci) and whole genome-MLST (1865 loci) to analyse 107 whole genomes via the Cronobacter PubMLST database. This database has enabled the retrospective analysis of historic cases and outbreaks following re-identification of those strains. The Cronobacter PubMLST database offers a central, open access, reliable sequence-based repository for researchers. It has the capacity to create new analysis schemes 'on the fly', and to integrate metadata (source, geographic distribution, clinical presentation). It is also expandable and adaptable to changes in taxonomy, and able to support the development of reliable detection methods of use to industry and regulatory authorities. Therefore it meets the WHO (2004) request for the establishment of a typing scheme for this emergent bacterial pathogen. Whole genome sequencing has additionally shown a range
Oster, Ryan J.; Wijesinghe, Rasanthi U.; Fogarty, Lisa Reynolds; Haack, Sheridan K.; Fogarty, Lisa R.; Tucker, Taaja R.; Riley, Stephen
Quantitative assessment of bacterial pathogens, their geographic variability, and distribution in various matrices at Great Lakes beaches are limited. Quantitative PCR (qPCR) was used to test for genes from E. coli O157:H7 (eaeO157), shiga-toxin producing E. coli (stx2), Campylobacter jejuni (mapA), Shigella spp. (ipaH), and a Salmonella enterica-specific (SE) DNA sequence at seven Great Lakes beaches, in algae, water, and sediment. Overall, detection frequencies were mapA>stx2>ipaH>SE>eaeO157. Results were highly variable among beaches and matrices; some correlations with environmental conditions were observed for mapA, stx2, and ipaH detections. Beach seasonal mean mapA abundance in water was correlated with beach seasonal mean log10E. coli concentration. At one beach, stx2 gene abundance was positively correlated with concurrent daily E. coli concentrations. Concentration distributions for stx2, ipaH, and mapA within algae, sediment, and water were statistically different (Non-Detect and Data Analysis in R). Assuming 10, 50, or 100% of gene copies represented viable and presumably infective cells, a quantitative microbial risk assessment tool developed by Michigan State University indicated a moderate probability of illness for Campylobacter jejuni at the study beaches, especially where recreational water quality criteria were exceeded. Pathogen gene quantification may be useful for beach water quality management.
Berry, Elaine D; Millner, Patricia D; Wells, James E; Kalchayanand, Norasak; Guerini, Michael N
Reducing Escherichia coli O157:H7 in livestock manures before application to cropland is critical for reducing the risk of foodborne illness associated with produce. Our objective was to determine the fate of naturally occurring E. coli O157:H7 and other pathogens during minimally managed on-farm bovine manure composting processes. Feedlot pen samples were screened to identify E. coli O157:H7-positive manure. Using this manure, four piles of each of three different composting formats were constructed in each of two replicate trials. Composting formats were (i) turned piles of manure plus hay and straw, (ii) static stockpiles of manure, and (iii) static piles of covered manure plus hay and straw. Temperatures in the tops, toes, and centers of the conical piles (ca. 6.0 m(3) each) were monitored. Compost piles that were turned every 2 weeks achieved higher temperatures for longer periods in the tops and centers than did piles that were left static. E. coli O157:H7 was not recovered from top samples of turned piles of manure plus hay and straw at day 28 and beyond, but top samples from static piles were positive for the pathogen up to day 42 (static manure stockpiles) and day 56 (static covered piles of manure plus hay and straw). Salmonella, Campylobacter spp., and Listeria monocytogenes were not found in top or toe samples at the end of the composting period, but E. coli O157:H7 and Listeria spp. were recovered from toe samples at day 84. Our findings indicate that some minimally managed composting processes can reduce E. coli O157:H7 and other pathogens in bovine manure but may be affected by season and/or initial levels of indigenous thermophilic bacteria. Our results also highlight the importance of adequate C:N formulation of initial mixtures for the production of high temperatures and rapid composting, and the need for periodic turning of the piles to increase the likelihood that all parts of the mass are subjected to high temperatures.
Ebrahimi, Azizollah; Hemati, Majid; Habibian Dehkordi, Saeed; Bahadoran, Shahab; Khoshnood, Sheida; Khubani, Shahin; Dokht Faraj, Mahdi; Hakimi Alni, Reza
To study chlorhexidine digluconate disinfectant effects on planktonic growth and biofilm formation in some bacterial field isolates from animals. The current study investigated chlorhexidine digluconate effects on planktonic growth and biofilm formation in some field isolates of veterinary bacterial pathogens. Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus. aureus and Streptococcus agalactiae (10 isolates for each) were examined for chlorhexidine digluconate effects on biofilm formation and planktonic growth using microtiter plates. In all of the examined strains in the presence of chlorhexidine digluconate, biofilm development and planktonic growth were affected at the same concentrations of the disinfectant. Chlorhexidine digluconate inhibited the planktonic growth of different bacterial species at sub-MICs. But they were able to induce biofilm development of the E. coli, Salmonella spp., S. aureus and Str. agalactiae strains. Bacterial resistance against chlorhexidine is increasing. Sub-MIC doses of chlorhexidine digluconate can stimulate the formation of biofilm strains.
Ebrahimi, Azizollah; Hemati, Majid; Habibian Dehkordi, Saeed; Bahadoran, Shahab; Khoshnood, Sheida; Khubani, Shahin; Dokht Faraj, Mahdi; Hakimi Alni, Reza
Background: To study chlorhexidine digluconate disinfectant effects on planktonic growth and biofilm formation in some bacterial field isolates from animals. Objectives: The current study investigated chlorhexidine digluconate effects on planktonic growth and biofilm formation in some field isolates of veterinary bacterial pathogens. Materials and Methods: Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus. aureus and Streptococcus agalactiae (10 isolates for each) were examined for chlorhexidine digluconate effects on biofilm formation and planktonic growth using microtiter plates. In all of the examined strains in the presence of chlorhexidine digluconate, biofilm development and planktonic growth were affected at the same concentrations of the disinfectant. Results: Chlorhexidine digluconate inhibited the planktonic growth of different bacterial species at sub-MICs. But they were able to induce biofilm development of the E. coli, Salmonella spp., S. aureus and Str. agalactiae strains. Conclusions: Bacterial resistance against chlorhexidine is increasing. Sub-MIC doses of chlorhexidine digluconate can stimulate the formation of biofilm strains. PMID:24872940
el-Abyad, M S; el-Sayed, M A; el-Shanshoury, A R; el-Sabbagh, S M
Thirty-seven actinomycete species isolated from fertile cultivated soils in Egypt were screened for the production of antimicrobial compounds against a variety of test organisms. Most of the isolates exhibited antimicrobial activities against Gram-positive, Gram-negative, and acid-fast bacteria, yeasts and filamentous fungi, with special attention to fungal and bacterial pathogens of tomato. On starch-nitrate agar, 14 strains were active against Fusarium oxysporum f.sp. lycopersici (the cause of Fusarium wilt), 18 against Verticillium albo-atrum (the cause of Verticillium wilt), and 18 against Alternaria solani (the cause of early blight). In liquid media, 14 isolates antagonized Pseudomonas solanacearum (the cause of bacterial wilt) and 20 antagonized Clavibacter michiganensis ssp. michiganensis (the cause of bacterial canker). The most active antagonists of the pathogenic microorganisms studied were found to be Streptomyces pulcher, S. canescens (syn. S. albidoflavus) and S. citreofluorescens (syn. S. anulatus). The antagonistic activities of S. pulcher and S. canescens against pathogenic fungi were assessed on solid media, and those of S. pulcher and S. citreofluorescens against pathogenic bacteria in liquid media under shaking conditions. The optimum culture conditions were determined.
Comparative Genomic and Phenotypic Characterization of Pathogenic and Non-Pathogenic Strains of Xanthomonas arboricola Reveals Insights into the Infection Process of Bacterial Spot Disease of Stone Fruits
Garita-Cambronero, Jerson; Palacio-Bielsa, Ana; López, María M.
Xanthomonas arboricola pv. pruni is the causal agent of bacterial spot disease of stone fruits, a quarantinable pathogen in several areas worldwide, including the European Union. In order to develop efficient control methods for this disease, it is necessary to improve the understanding of the key determinants associated with host restriction, colonization and the development of pathogenesis. After an initial characterization, by multilocus sequence analysis, of 15 strains of X. arboricola isolated from Prunus, one strain did not group into the pathovar pruni or into other pathovars of this species and therefore it was identified and defined as a X. arboricola pv. pruni look-a-like. This non-pathogenic strain and two typical strains of X. arboricola pv. pruni were selected for a whole genome and phenotype comparative analysis in features associated with the pathogenesis process in Xanthomonas. Comparative analysis among these bacterial strains isolated from Prunus spp. and the inclusion of 15 publicly available genome sequences from other pathogenic and non-pathogenic strains of X. arboricola revealed variations in the phenotype associated with variations in the profiles of TonB-dependent transporters, sensors of the two-component regulatory system, methyl accepting chemotaxis proteins, components of the flagella and the type IV pilus, as well as in the repertoire of cell-wall degrading enzymes and the components of the type III secretion system and related effectors. These variations provide a global overview of those mechanisms that could be associated with the development of bacterial spot disease. Additionally, it pointed out some features that might influence the host specificity and the variable virulence observed in X. arboricola. PMID:27571391
Jacob Inbaneson, Samuel; Ravikumar, Sundaram; Manikandan, Nachiappan
The silver nanoparticles were synthesized by chemical reduction method and the nanoparticles were characterized using ultraviolet-visible (UV-Vis) absorption spectroscopy and X-ray diffraction (XRD) studies. The synthesized silver nanoparticles were investigated to evaluate the antibacterial activity against urinary tract infectious (UTIs) bacterial pathogens. Thirty-two bacteria were isolated from mid urine samples of 25 male and 25 female patients from Thondi, Ramanathapuram District, Tamil Nadu, India and identified by conventional methods. Escherichia coli was predominant (47%) followed by Pseudomonas aeruginosa (22%), Klebsiella pneumoniae (19%), Enterobacter sp. (6%), Proteus morganii (3%) and Staphylococcus aureus (3%). The antibacterial activity of silver nanoparticles was evaluated by disc diffusion assay. P. aeruginosa showed maximum sensitivity (11 ± 0.58 mm) followed by Enterobacter sp. (8 ± 0.49 mm) at a concentration of 20 μg disc-1 and the sensitivity was highly comparable with the positive control kanamycin and tetracycline. K. pneumoniae, E. coli, P. morganii and S. aureus showed no sensitivity against all the tested concentrations of silver nanoparticles. The results provided evidence that, the silver nanoparticles might indeed be the potential sources to treat urinary tract infections caused by P. aeruginosa and Enterobacter sp.
Becker, Holger; Hlawatsch, Nadine; Haraldsson, Tommy; van der Wijngaart, Wouter; Lind, Anders; Malhotra-Kumar, Surbi; Turlej-Rogacka, Agata; Goossens, Herman
Urinary tract infections (UTIs) are among the most common bacterial infections and pose a significant healthcare burden. The growing trend in antibiotic resistance makes it mandatory to develop diagnostic kits which allow not only the determination of a pathogen but also the antibiotic resistances. We have developed a microfluidic cartridge which takes a direct urine sample, extracts the DNA, performs an amplification using batch-PCR and flows the sample over a microarray which is printed into a microchannel for fluorescence detection. The cartridge is injection-molded out of COP and contains a set of two-component injection-molded rotary valves to switch between input and to isolate the PCR chamber during thermocycling. The hybridization probes were spotted directly onto a functionalized section of the outlet microchannel. We have been able to successfully perform PCR of E.coli in urine in this chip and perform a fluorescence detection of PCR products. An upgraded design of the cartridge contains the buffers and reagents in blisters stored on the chip.
Chen, Xin-hai; Liu, Shi-rao; Peng, Bo; Li, Dan; Cheng, Zhi-xue; Zhu, Jia-xin; Zhang, Song; Peng, Yu-ming; Li, Hui; Zhang, Tian-tuo; Peng, Xuan-xian
The emergence of multidrug-resistant bacteria presents a severe threat to public health and causes extensive losses in livestock husbandry and aquaculture. Effective strategies to control such infections are in high demand. Enhancing host immunity is an ideal strategy with fewer side effects than antibiotics. To explore metabolite candidates, we applied a metabolomics approach to investigate the metabolic profiles of mice after Klebsiella pneumoniae infection. Compared with the mice that died from K. pneumoniae infection, mice that survived the infection displayed elevated levels of l-valine. Our analysis showed that l-valine increased macrophage phagocytosis, thereby reducing the load of pathogens; this effect was not only limited to K. pneumoniae but also included Escherichia coli clinical isolates in infected tissues. Two mechanisms are involved in this process: l-valine activating the PI3K/Akt1 pathway and promoting NO production through the inhibition of arginase activity. The NO precursor l-arginine is necessary for l-valine-stimulated macrophage phagocytosis. The valine-arginine combination therapy effectively killed K. pneumoniae and exerted similar effects in other Gram-negative (E. coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. Our study extends the role of metabolism in innate immunity and develops the possibility of employing the metabolic modulator-mediated innate immunity as a therapy for bacterial infections. PMID:28321214
Chopyk, Jessica; Moore, Ryan M; DiSpirito, Zachary; Stromberg, Zachary R; Lewis, Gentry L; Renter, David G; Cernicchiaro, Natalia; Moxley, Rodney A; Wommack, K Eric
Since 1982, specific serotypes of Shiga toxin-producing Escherichia coli (STEC) have been recognized as significant foodborne pathogens acquired from contaminated beef and, more recently, other food products. Cattle are the major reservoir hosts of these organisms, and while there have been advancements in food safety practices and industry standards, STEC still remains prevalent within beef cattle operations with cattle hides implicated as major sources of carcass contamination. To investigate whether the composition of hide-specific microbial communities are associated with STEC prevalence, 16S ribosomal RNA (rRNA) bacterial community profiles were obtained from hide and fecal samples collected from a large commercial feedlot over a 3-month period. These community data were examined amidst an extensive collection of prevalence data on a subgroup of STEC that cause illness in humans, referred to as enterohemorrhagic E. coli (EHEC). Fecal 16S rRNA gene OTUs (operational taxonomic units) were subtracted from the OTUs found within each hide 16S rRNA amplicon library to identify hide-specific bacterial populations. Comparative analysis of alpha diversity revealed a significant correlation between low bacterial diversity and samples positive for the presence of E. coli O157:H7 and/or the non-O157 groups: O26, O111, O103, O121, O45, and O145. This trend occurred regardless of diversity metric or fecal OTU presence. The number of EHEC serogroups present in the samples had a compounding effect on the inverse relationship between pathogen presence and bacterial diversity. Beta diversity data showed differences in bacterial community composition between samples containing O157 and non-O157 populations, with certain OTUs demonstrating significant changes in relative abundance. The cumulative prevalence of the targeted EHEC serogroups was correlated with low bacterial community diversity on pre-harvest cattle hides. Understanding the relationship between indigenous hide
Ashraf, Aqeela; Imran, Muhammad; Yaqub, Tahir; Tayyab, Muhammad; Shehzad, Wasim; Thomson, Peter C
For rapid and simultaneous detection of nine bovine mastitic pathogens, a sensitive and specific multiplex PCR assay was developed. The assay was standardized using reference strains and validated on mastitic milk cultures which were identified to species level based on 16S rRNA sequencing. Multiplex PCR assay also efficiently detected the target bacterial strains directly from milk. The detection limit of the assay was up to 50 pg for DNA isolated from pure cultures and 10 4 CFU/ml for spiked milk samples. As estimated by latent class analysis, the assay was sensitive up to 88% and specific up to 98% for targeted mastitic pathogens, compared with the bacterial culture method and the 16S rRNA sequence analysis. This novel molecular assay could be useful for monitoring and maintaining the bovine udder health, ensuring the bacteriological safety of milk, and conducting epidemiological studies. Copyright © 2017 Elsevier Ltd. All rights reserved.
Abdelkader, Mona M; Aboshanab, Khaled M; El-Ashry, Marwa A; Aboulwafa, Mohammad M
The aim of this study was identifying bacterial pathogens involved in meningitis, studying their antibiotic resistance profiles, investigating the antibiotic resistance genes as well as evaluating the use of various antibiotic combinations. Antibiotic susceptibility tests were evaluated according to CLSI guidelines. Antibiotic combinations were evaluated by calculating the Fractional Inhibitory Concentration (FIC) index. A total of 71 bacterial isolates were recovered from 68 culture positive CSF specimens. Sixty five of these isolates (91.5%) were recovered from single infection specimens, while 6 isolates (8.4%) were recovered from mixed infection specimens. Out of the 71 recovered isolates, 48 (67.6%) were Gram-positive, and 23 (32.4%) were Gram-negative. Thirty one of the Gram positive isolates were S. pneumoniae (64.6%, n = 48). Out of the recovered 71 isolates; 26 (36.6%) were multidrug-resistant (MDR) isolates of which, 18 (69.2%) were Gram-negative and 8 (30.8%) were Gram-positive. All MDR isolates (100%) showed resistance to penicillin and ampicillin, however, they showed lower resistance to meropenem (50%), levofloxacin (50%), amikacin (48%), pipercillin-tazobactam (45.8%). Most common antibiotic resistance genes were investigated including: tem (21.1%), shv (15.8%), ctx-m (15.8%) coding for TEM-, SHV, CTX-M extended-spectrum beta-lactamases (ESBLs), respectively; aac(6')-I b(26.3%) coding for aminoglycoside 6'-N-acetyltransferase type Ib ciprofloxacin resistant variant; and qnrA (5.3%) gene coding for quinolone resistance. The DNA sequences of the respective resistance genes of some selected isolates were PCR amplified, analyzed and submitted to the GenBank database under the accession numbers, KX214665, KX214664, KX214663, KX214662, respectively. The FIC values for ampicillin/sulbactam plus cefepime showed either additive or synergistic effect against ten tested Gram-negative MDR isolates, while doxycycline plus levofloxacin combination revealed
Guo, Geyong; Zhou, Huaijuan; Wang, Qiaojie; Wang, Jiaxing; Tan, Jiaqi; Li, Jinhua; Jin, Ping; Shen, Hao
Biomaterial-related bacterial infections cause patient suffering, mortality and extended periods of hospitalization, imposing a substantial burden on medical systems. In this context, understanding of nanomaterials-bacteria-cells interactions is of both fundamental and clinical significance. Herein, nano-MgF 2 films were deposited on titanium substrate via magnetron sputtering. Using this platform, the antibacterial behavior and mechanism of the nano-MgF 2 films were investigated in vitro and in vivo. It was found that, for S. aureus (CA-MRSA, USA300) and S. epidermidis (RP62A), the nano-MgF 2 films possessed excellent anti-biofilm activity, but poor anti-planktonic bacteria activity in vitro. Nevertheless, both the traditional SD rat osteomyelitis model and the novel stably luminescent mouse infection model demonstrated that nano-MgF 2 films exerted superior anti-infection effect in vivo, which cannot be completely explained by the antibacterial activity of the nanomaterial itself. Further, using polymorphonuclear leukocytes (PMNs), the critical immune cells of innate immunity, a complementary investigation of MgF 2 -bacteria-PMNs co-culturing revealed that the nano-MgF 2 films improved the antibacterial effect of PMNs through enhancing their phagocytosis and stability. To our knowledge, this is the first time of exploring the antimicrobial mechanism of nano-MgF 2 from the perspective of innate immunity both in vitro and in vivo. Based on the research results, a plausible mechanism is put forward for the predominant antibacterial effect of nano-MgF 2 in vivo, which may originate from the indirect immune enhancement effect of nano-MgF 2 films. In summary, this study of surface antibacterial design using MgF 2 nanolayer is a meaningful attempt, which can promote the host innate immune response to bacterial pathogens. This may give us a new understanding towards the antibacterial behavior and mechanism of nano-MgF 2 films and pave the way towards their clinical
A cross-sectional study examining Campylobacter and other zoonotic enteric pathogens in dogs that frequent dog parks in three cities in south-western Ontario and risk factors for shedding of Campylobacter spp.
Procter, T D; Pearl, D L; Finley, R L; Leonard, E K; Janecko, N; Reid-Smith, R J; Weese, J S; Peregrine, A S; Sargeant, J M
An estimated 6 million pet dogs live in Canadian households with the potential to transmit zoonotic pathogens to humans. Dogs have been identified as carriers of Salmonella, Giardia and Campylobacter spp., particularly Campylobacter upsaliensis, but little is known about the prevalence and risk factors for these pathogens in pet dogs that visit dog parks. This study examined the prevalence of these organisms in the faeces of dogs visiting dog parks in three cities in south-western Ontario, as well as risk factors for shedding Campylobacter spp. and C. upsaliensis. From May to August 2009, canine faecal samples were collected at ten dog parks in the cities of Guelph and Kitchener-Waterloo, Ontario, Canada. Owners were asked to complete a questionnaire related to pet characteristics and management factors including age, diet and activities in which the dog participates. Faecal samples were collected from 251 dogs, and 189 questionnaires were completed. Salmonella, Giardia and Campylobacter spp. were present in 1.2%, 6.4% and 43.0% of faecal samples, respectively. Of the Campylobacter spp. detected, 86.1% were C. upsaliensis, 13% were C. jejuni and 0.9% were C. coli. Statistically significant sparing factors associated with the shedding of Campylobacter spp. included the feeding of a commercial dry diet and the dog's exposure to compost. Age of dog had a quadratic effect, with young dogs and senior dogs having an increased probability of shedding Campylobacter spp. compared with adult dogs. The only statistically significant risk factor for shedding C. upsaliensis was outdoor water access including lakes and ditches, while dogs >1 year old were at a lower risk than young dogs. Understanding the pet-related risk factors for Campylobacter spp. and C. upsaliensis shedding in dogs may help in the development of awareness and management strategies to potentially reduce the risk of transmitting this pathogen from dogs to humans. © 2013 Blackwell Verlag GmbH.
Moumouni, Aissatou; Gouali, Malika; Mamaty, Abdoul-Aziz; Grais, Rebecca F.
Background Although rotavirus is the leading cause of severe diarrhea among children in sub-Saharan Africa, better knowledge of circulating enteric pathogenic bacteria and their antimicrobial resistance is crucial for prevention and treatment strategies. Methodology/Principal Findings As a part of rotavirus gastroenteritis surveillance in Maradi, Niger, we performed stool culture on a sub-population of children under 5 with moderate-to-severe diarrhea between April 2010 and March 2012. Campylobacter, Shigella and Salmonella were sought with conventional culture and biochemical methods. Shigella and Salmonella were serotyped by slide agglutination. Enteropathogenic Escherichia coli (EPEC) were screened by slide agglutination with EPEC O-typing antisera and confirmed by detection of virulence genes. Antimicrobial susceptibility was determined by disk diffusion. We enrolled 4020 children, including 230 with bloody diarrhea. At least one pathogenic bacterium was found in 28.0% of children with watery diarrhea and 42.2% with bloody diarrhea. Mixed infections were found in 10.3% of children. EPEC, Salmonella and Campylobacter spp. were similarly frequent in children with watery diarrhea (11.1%, 9.2% and 11.4% respectively) and Shigella spp. were the most frequent among children with bloody diarrhea (22.1%). The most frequent Shigella serogroup was S. flexneri (69/122, 56.5%). The most frequent Salmonella serotypes were Typhimurimum (71/355, 20.0%), Enteritidis (56/355, 15.8%) and Corvallis (46/355, 13.0%). The majority of putative EPEC isolates was confirmed to be EPEC (90/111, 81.1%). More than half of all Enterobacteriaceae were resistant to amoxicillin and co-trimoxazole. Around 13% (46/360) Salmonella exhibited an extended-spectrum beta-lactamase phenotype. Conclusions This study provides updated information on enteric bacteria diversity and antibiotic resistance in the Sahel region, where such data are scarce. Whether they are or not the causative agent of diarrhea
van Agtmaal, Maaike; van Os, Gera J.; Hol, W.H. Gera; Hundscheid, Maria P.J.; Runia, Willemien T.; Hordijk, Cornelis A.; de Boer, Wietse
There is increasing evidence that microbial volatiles (VOCs) play an important role in natural suppression of soil-borne diseases, but little is known on the factors that influence production of suppressing VOCs. In the current study we examined whether a stress-induced change in soil microbial community composition would affect the production by soils of VOCs suppressing the plant-pathogenic oomycete Pythium. Using pyrosequencing of 16S ribosomal gene fragments we compared the composition of bacterial communities in sandy soils that had been exposed to anaerobic disinfestation (AD), a treatment used to kill harmful soil organisms, with the composition in untreated soils. Three months after the AD treatment had been finished, there was still a clear legacy effect of the former anaerobic stress on bacterial community composition with a strong increase in relative abundance of the phylum Bacteroidetes and a significant decrease of the phyla Acidobacteria, Planctomycetes, Nitrospirae, Chloroflexi, and Chlorobi. This change in bacterial community composition coincided with loss of production of Pythium suppressing soil volatiles (VOCs) and of suppression of Pythium impacts on Hyacinth root development. One year later, the composition of the bacterial community in the AD soils was reflecting that of the untreated soils. In addition, both production of Pythium-suppressing VOCs and suppression of Pythium in Hyacinth bioassays had returned to the levels of the untreated soil. GC/MS analysis identified several VOCs, among which compounds known to be antifungal, that were produced in the untreated soils but not in the AD soils. These compounds were again produced 15 months after the AD treatment. Our data indicate that soils exposed to a drastic stress can temporarily lose pathogen suppressive characteristics and that both loss and return of these suppressive characteristics coincides with shifts in the soil bacterial community composition. Our data are supporting the
Visser, M; Stephan, D; Jaynes, J M; Burger, J T
Natural and synthetic antimicrobial peptides (AMPs) are of increasing interest as potential resistance conferring elements in plants against pathogen infection. The efficacy of AMPs against pathogens is prescreened by in vitro assays, and promising AMP candidates are introduced as transgenes into plants. As in vitro and in planta environments differ, a prescreening procedure of the AMP efficacy in the plant environment is desired. Here, we report the efficacy of the purified synthetic peptide D4E1 against the grapevine-infecting bacterial pathogens Agrobacterium vitis and Xylophilus ampelinus in vitro and describe for the first time an in planta prescreening procedure based on transiently expressed D4E1. The antimicrobial effect of D4E1 against Ag. vitis and X. ampelinus was shown by a reduction in colony-forming units in vitro in a traditional plate-based assay and by a reduction in bacterial titres in planta as measured by quantitative real-time PCR (qPCR) in grapevine leaves transiently expressing D4E1. A statistically significant reduction in titre was shown for X. ampelinus, but for Ag. vitis, a significant reduction in titre was only observed in a subset of plants. The titres of both grapevine-infecting bacterial pathogens were reduced in an in vitro assay and for X. ampelinus in an in planta assay by D4E1 application. This widens the applicability of D4E1 as a potential resistance-enhancing element to additional pathogens and in a novel plant species. D4E1 is a promising candidate to confer enhanced resistance against the two tested grapevine bacterial pathogens, and the applied transient expression system proved to be a valuable tool for prescreening of D4E1 efficacy in an in planta environment. The described prescreening procedure can be used for other AMPs and might be adapted to other plant species and pathogens before the expensive and tedious development of stably transgenic lines is started. © 2012 The Authors. Letters in Applied Microbiology © 2012
Castro, Felipe D; Sedman, Jacqueline; Ismail, Ashraf A; Asadishad, Bahareh; Tufenkji, Nathalie
The effects of dissolved oxygen tension during bacterial growth and acclimation on the cell surface properties and biochemical composition of the bacterial pathogens Escherichia coli O157:H7 and Yersinia enterocolitica are characterized. Three experimental techniques are used in an effort to understand the influence of bacterial growth and acclimation conditions on cell surface charge and the composition of the bacterial cell: (i) electrophoretic mobility measurements; (ii) potentiometric titration; and (iii) ATR-FTIR spectroscopy. Potentiometric titration data analyzed using chemical speciation software are related to measured electrophoretic mobilities at the pH of interest. Titration of bacterial cells is used to identify the major proton-active functional groups and the overall concentration of these cell surface ligands at the cell membrane. Analysis of titration data shows notable differences between strains and conditions, confirming the appropriateness of this tool for an overall charge characterization. ATR-FTIR spectroscopy of whole cells is used to further characterize the bacterial biochemical composition and macromolecular structures that might be involved in the development of the net surficial charge of the organisms examined. The evaluation of the integrated intensities of HPO(2)(-) and carbohydrate absorption bands in the IR spectra reveals clear differences between growth protocols. Taken together, the three techniques seem to indicate that the dissolved oxygen tension during cell growth or acclimation can noticeably influence the expression of cell surface molecules and the measurable cell surface charge, though in a strain-dependent fashion.
Zhou, Lijuan; Powell, Charles A; Li, Wenbin; Irey, Mike; Duan, Yongping
Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and disease development.
Whiteside, Matthew D; Laing, Chad R; Manji, Akiff; Kruczkiewicz, Peter; Taboada, Eduardo N; Gannon, Victor P J
Predictive genomics is the translation of raw genome sequence data into a phenotypic assessment of the organism. For bacterial pathogens, these phenotypes can range from environmental survivability, to the severity of human disease. Significant progress has been made in the development of generic tools for genomic analyses that are broadly applicable to all microorganisms; however, a fundamental missing component is the ability to analyze genomic data in the context of organism-specific phenotypic knowledge, which has been accumulated from decades of research and can provide a meaningful interpretation of genome sequence data. In this study, we present SuperPhy, an online predictive genomics platform ( http://lfz.corefacility.ca/superphy/ ) for Escherichia coli. The platform integrates the analytical tools and genome sequence data for all publicly available E. coli genomes and facilitates the upload of new genome sequences from users under public or private settings. SuperPhy provides real-time analyses of thousands of genome sequences with results that are understandable and useful to a wide community, including those in the fields of clinical medicine, epidemiology, ecology, and evolution. SuperPhy includes identification of: 1) virulence and antimicrobial resistance determinants 2) statistical associations between genotypes, biomarkers, geospatial distribution, host, source, and phylogenetic clade; 3) the identification of biomarkers for groups of genomes on the based presence/absence of specific genomic regions and single-nucleotide polymorphisms and 4) in silico Shiga-toxin subtype. SuperPhy is a predictive genomics platform that attempts to provide an essential link between the vast amounts of genome information currently being generated and phenotypic knowledge in an organism-specific context.
McLean, Christopher J.; Marles-Wright, Jon; Custodio, Rafael; Lowther, Jonathan; Kennedy, Amanda J.; Pollock, Jacob; Clarke, David J.; Brown, Alan R.; Campopiano, Dominic J.
Sphingolipids (SLs) are ubiquitous elements in eukaryotic membranes and are also found in some bacterial and viral species. As well as playing an integral structural role, SLs also act as potent signaling molecules involved in numerous cellular pathways and have been linked to many human diseases. A central SL signaling molecule is sphingosine-1-phosphate (S1P), whose breakdown is catalyzed by S1P lyase (S1PL), a pyridoxal 5′-phosphate (PLP)-dependent enzyme that catalyzes the cleavage of S1P to (2E)-hexadecenal (2E-HEX) and phosphoethanolamine. Here, we show that the pathogenic bacterium, Burkholderia pseudomallei K96243, encodes two homologous proteins (S1PL2021 and S1PL2025) that display moderate sequence identity to known eukaryotic and prokaryotic S1PLs. Using an established MS-based methodology, we show that recombinant S1PL2021 is catalytically active. We also used recombinant human fatty aldehyde dehydrogenase to develop a spectrophotometric enzyme-coupled assay to detect 2E-HEX formation and measure the kinetic constants of the two B. pseudomallei S1PL isoforms. Furthermore, we determined the X-ray crystal structure of the PLP-bound form of S1PL2021 at 2.1 Å resolution revealing that the enzyme displays a conserved structural fold and active site architecture comparable with known S1PLs. The combined data suggest that B. pseudomallei has the potential to degrade host SLs in a S1PL-dependent manner. PMID:27784725
Haack, S.K.; Duris, J.W.; Fogarty, L.R.; Kolpin, D.W.; Focazio, M.J.; Furlong, E.T.; Meyer, M.T.
The objective of this study was to compare fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli [EC], and enterococci [ENT]) concentrations with a wide array of typical organic wastewater chemicals and selected bacterial genes as indicators of fecal pollution in water samples collected at or near 18 surface water drinking water intakes. Genes tested included esp (indicating human-pathogenic ENT) and nine genes associated with various animal sources of shiga-toxin-producing EC (STEC). Fecal pollution was indicated by genes and/or chemicals for 14 of the 18 tested samples, with little relation to FIB standards. Of 13 samples with <50 EC 100 mL-1, human pharmaceuticals or chemical indicators of wastewater treatment plant effluent occurred in six, veterinary antibiotics were detected in three, and stx1 or stx2 genes (indicating varying animal sources of STEC) were detected in eight. Only the EC eaeA gene was positively correlated with FIB concentrations. Human-source fecal pollution was indicated by the esp gene and the human pharmaceutical carbamazepine in one of the nine samples that met all FIB recreational water quality standards. Escherichia coli rfbO157 and stx2c genes, which are typically associated with cattle sources and are of potential human health significance, were detected in one sample in the absence of tested chemicals. Chemical and gene-based indicators of fecal contamination may be present even when FIB standards are met, and some may, unlike FIB, indicate potential sources. Application of multiple water quality indicators with variable environmental persistence and fate may yield greater confidence in fecal pollution assessment and may inform remediation decisions. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.
van Bree, Freek P J; Bokken, Gertie C A M; Mineur, Robin; Franssen, Frits; Opsteegh, Marieke; van der Giessen, Joke W B; Lipman, Len J A; Overgaauw, Paul A M
Feeding raw meat-based diets (RMBDs) to companion animals has become increasingly popular. Since these diets may be contaminated with bacteria and parasites, they may pose a risk to both animal and human health. The purpose of this study was to test for the presence of zoonotic bacterial and parasitic pathogens in Dutch commercial RMBDs. We analysed 35 commercial frozen RMBDs from eight different brands. Escherichia coli serotype O157:H7 was isolated from eight products (23 per cent) and extended-spectrum beta-lactamases-producing E coli was found in 28 products (80 per cent). Listeria monocytogenes was present in 19 products (54 per cent), other Listeria species in 15 products (43 per cent) and Salmonella species in seven products (20 per cent). Concerning parasites, four products (11 per cent) contained Sarcocystis cruzi and another four (11 per cent) S tenella In two products (6 per cent) Toxoplasma gondii was found. The results of this study demonstrate the presence of potential zoonotic pathogens in frozen RMBDs that may be a possible source of bacterial infections in pet animals and if transmitted pose a risk for human beings. If non-frozen meat is fed, parasitic infections are also possible. Pet owners should therefore be informed about the risks associated with feeding their animals RMBDs. © British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
Lees, John A.; Kremer, Philip H. C.; Manso, Ana S.; Croucher, Nicholas J.; Ferwerda, Bart; Serón, Mercedes Valls; Oggioni, Marco R.; Parkhill, Julian; Brouwer, Matthijs C.; van der Ende, Arie; van de Beek, Diederik
Recent studies have provided evidence for rapid pathogen genome diversification, some of which could potentially affect the course of disease. We have previously described such variation seen between isolates infecting the blood and cerebrospinal fluid (CSF) of a single patient during a case of bacterial meningitis. Here, we performed whole-genome sequencing of paired isolates from the blood and CSF of 869 meningitis patients to determine whether such variation frequently occurs between these two niches in cases of bacterial meningitis. Using a combination of reference-free variant calling approaches, we show that no genetic adaptation occurs in either invaded niche during bacterial meningitis for two major pathogen species, Streptococcus pneumoniae and Neisseria meningitidis. This study therefore shows that the bacteria capable of causing meningitis are already able to do this upon entering the blood, and no further sequence change is necessary to cross the blood–brain barrier. Our findings place the focus back on bacterial evolution between nasopharyngeal carriage and invasion, or diversity of the host, as likely mechanisms for determining invasiveness. PMID:28348877
Whalen, M C; Innes, R W; Bent, A F; Staskawicz, B J
To develop a model system for molecular genetic analysis of plant-pathogen interactions, we studied the interaction between Arabidopsis thaliana and the bacterial pathogen Pseudomonas syringae pv tomato (Pst). Pst strains were found to be virulent or avirulent on specific Arabidopsis ecotypes, and single ecotypes were resistant to some Pst strains and susceptible to others. In many plant-pathogen interactions, disease resistance is controlled by the simultaneous presence of single plant resistance genes and single pathogen avirulence genes. Therefore, we tested whether avirulence genes in Pst controlled induction of resistance in Arabidopsis. Cosmids that determine avirulence were isolated from Pst genomic libraries, and the Pst avirulence locus avrRpt2 was defined. This allowed us to construct pathogens that differed only by the presence or absence of a single putative avirulence gene. We found that Arabidopsis ecotype Col-0 was susceptible to Pst strain DC3000 but resistant to the same strain carrying avrRpt2, suggesting that a single locus in Col-0 determines resistance. As a first step toward genetically mapping the postulated resistance locus, an ecotype susceptible to infection by DC3000 carrying avrRpt2 was identified. The avrRpt2 locus from Pst was also moved into virulent strains of the soybean pathogen P. syringae pv glycinea to test whether this locus could determine avirulence on soybean. The resulting strains induced a resistant response in a cultivar-specific manner, suggesting that similar resistance mechanisms may function in Arabidopsis and soybean.
Scalfaro, Concetta; Iacobino, Angelo; Nardis, Chiara; Franciosa, Giovanna
The antagonistic activity against gastrointestinal bacterial pathogens is an important property of probiotic bacteria and a desirable feature for pre-selection of novel strains with probiotic potential. Pre-screening of candidate probiotics for antibacterial activity should be based on in vitro and in vivo tests. This study investigated whether the protective activity of probiotic bacteria against gastrointestinal bacterial pathogens can be evaluated using Galleria mellonella larvae as an in vivo model. Larvae were pre-inoculated with either of two widely used probiotic bacteria, Lactobacillus rhamnosus GG or Clostridium butyricum Miyairi 588, and then challenged with Salmonella enterica Typhimurium, enteropathogenic Escherichia coli or Listeria monocytogenes. Survival rates increased in the probiotic pretreated larvae compared with control larvae inoculated with pathogens only. The hemocyte density increased as well in the probiotic pretreated larvae, indicating that both probiotics induce an immune response in the larvae. The antibacterial activity of probiotics against the pathogens was also assayed by an in vitro agar spot test: results were partially consistent with those obtained by the G. mellonella protection assay. The results obtained, as a whole, suggest that G. mellonella larvae are a potentially useful in vivo model that can complement in vitro assays for pre-screening of candidate probiotics. © FEMS 2017. All rights reserved. For permissions, please e-mail: email@example.com.
Raja, B; Goux, H J; Marapadaga, A; Rajagopalan, S; Kourentzi, K; Willson, R C
To develop and evaluate the performance of a panel of isothermal real-time recombinase polymerase amplification (RPA) assays for detection of common bacterial urinary tract infection (UTI) pathogens. The panel included RPAs for Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Enterococcus faecalis. All five RPAs required reaction times of under 12 min to reach their lower limit of detection of 100 genomes per reaction or less, and did not cross-react with high concentrations of nontarget bacterial genomic DNA. In a 50-sample retrospective clinical study, the five-RPA assay panel was found to have a specificity of 100% (95% CI, 78-100%) and a sensitivity of 89% (95% CI, 75-96%) for UTI detection. The analytical and clinical validity of RPA for the rapid and sensitive detection of common UTI pathogens was established. Rapid identification of the causative pathogens of UTIs can be valuable in preventing serious complications by helping avoid the empirical treatment necessitated by traditional urine culture's 48-72-h turnaround time. The routine and widespread use of RPA to supplement or replace culture-based methods could profoundly impact UTI management and the emergence of multidrug-resistant pathogens. © 2017 The Society for Applied Microbiology.
Khan, Abdul Viqar; Ahmed, Qamar Uddin; Mir, M Ramzan; Shukla, Indu; Khan, Athar Ali
Objective To investigate the antibacterial potential of the polar and non-polar extracts of the seeds of Melia azedarach (M. azedarach) L. (Meliaceae) against eighteen hospital isolated human pathogenic bacterial strains. Methods Petrol, benzene, ethyl acetate, methanol, and aqueous extracts at five different concentrations (1, 2, 5, 10 and 15 mg/mL) were evaluated. Disk diffusion method was followed to evaluate the antibacterial efficacy. Results All extracts of the seeds demonstrated significant antibacterial activity against tested pathogens. Among all extracts, ethyl acetate extract revealed the highest inhibition comparatively. The present study also favored the traditional uses reported earlier. Conclusions Results of this study strongly confirm that the seed extracts of M. azedarach could be effective antibiotics, both in controlling gram-positive and gram-negative human pathogenic infections. PMID:23569812
Jiang, Hong; Zheng, Xuyang; Wang, Limei; Du, Hong; Wang, Pingzhong; Bai, Xuefan
Hantaviruses are comprised of tri-segmented negative sense single-stranded RNA, and are members of the Bunyaviridae family. Hantaviruses are distributed worldwide and are important zoonotic pathogens that can have severe adverse effects in humans. They are naturally maintained in specific reservoir hosts without inducing symptomatic infection. In humans, however, hantaviruses often cause two acute febrile diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS). In this paper, we review the epidemiology and epizootiology of hantavirus infections worldwide.
... when exposed skin comes in contact with contaminated soil or sand. The larvae in the contaminated soil or sand will burrow into the skin and ... measures to avoid skin contact with sand or soil will prevent infection with zoonotic hookworms. Travelers to ...
Mann, Rajinder S; Ali, Jared G; Hermann, Sara L; Tiwari, Siddharth; Pelz-Stelinski, Kirsten S; Alborn, Hans T; Stelinski, Lukasz L
Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las), affects host preference behavior of its psyllid (Diaphorina citri Kuwayama) vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of specific headspace
Mitchell, Mark A
Reptiles and amphibians are popular as pets. There are increased concerns among public health officials because of the zoonotic potential associated with these animals. Encounters with reptiles and amphibians are also on the rise in the laboratory setting and with wild animals; in both of these practices, there is also an increased likelihood for exposure to zoonotic pathogens. It is important that veterinarians remain current with the literature as it relates to emerging and reemerging zoonotic diseases attributed to reptiles and amphibians so that they can protect themselves, their staff, and their clients from potential problems.
Morris, Cindy E; Barny, Marie-Anne; Berge, Odile; Kinkel, Linda L; Lacroix, Christelle
Methods to ensure the health of crops owe their efficacy to the extent to which we understand the ecology and biology of environmental microorganisms and the conditions under which their interactions with plants lead to losses in crop quality or yield. However, in the pursuit of this knowledge, notions of the ecology of plant-pathogenic microorganisms have been reduced to a plant-centric and agro-centric focus. With increasing global change, i.e. changes that encompass not only climate, but also biodiversity, the geographical distribution of biomes, human demographic and socio-economic adaptations and land use, new plant health problems will emerge via a range of processes influenced by these changes. Hence, knowledge of the ecology of plant pathogens will play an increasingly important role in the anticipation and response to disease emergence. Here, we present our opinion on the major challenges facing the study of the ecology of plant-pathogenic bacteria. We argue that the discovery of markedly novel insights into the ecology of plant-pathogenic bacteria is most likely to happen within a framework of more extensive scales of space, time and biotic interactions than those that currently guide much of the research on these bacteria. This will set a context that is more propitious for the discovery of unsuspected drivers of the survival and diversification of plant-pathogenic bacteria and of the factors most critical for disease emergence, and will set the foundation for new approaches to the sustainable management of plant health. We describe the contextual background of, justification for and specific research questions with regard to the following challenges: Development of terminology to describe plant-bacterial relationships in terms of bacterial fitness. Definition of the full scope of the environments in which plant-pathogenic bacteria reside or survive. Delineation of pertinent phylogenetic contours of plant-pathogenic bacteria and naming of strains
Blom, Anna M; Magda, Michal; Kohl, Lisa; Shaughnessy, Jutamas; Lambris, John D; Ram, Sanjay; Ermert, David
Bacteria can cause life-threatening infections, such as pneumonia, meningitis, or sepsis. Antibiotic therapy is a mainstay of treatment, although antimicrobial resistance has drastically increased over the years. Unfortunately, safe and effective vaccines against most pathogens have not yet been approved, and thus developing alternative treatments is important. We analyzed the efficiency of factor H (FH)6-7/Fc, a novel antibacterial immunotherapeutic protein against the Gram-positive bacterium Streptococcus pyogenes This protein is composed of two domains of complement inhibitor human FH (FH complement control protein modules 6 and 7) that bind to S. pyogenes , linked to the Fc region of IgG (FH6-7/Fc). FH6-7/Fc has previously been shown to enhance complement-dependent killing of, and facilitate bacterial clearance in, animal models of the Gram-negative pathogens Haemophilus influenzae and Neisseria meningitidis We hypothesized that activation of complement by FH6-7/Fc on the surface of Gram-positive bacteria such as S. pyogenes will enable professional phagocytes to eliminate the pathogen. We found that FH6-7/Fc alleviated S. pyogenes- induced sepsis in a transgenic mouse model expressing human FH ( S. pyogenes binds FH in a human-specific manner). Furthermore, FH6-7/Fc, which binds to protein H and selected M proteins, displaced FH from the bacterial surface, enhanced alternative pathway activation, and reduced bacterial blood burden by opsonophagocytosis in a C3-dependent manner in an ex vivo human whole-blood model. In conclusion, FH-Fc chimeric proteins could serve as adjunctive treatments against multidrug-resistant bacterial infections. Copyright © 2017 by The American Association of Immunologists, Inc.
Driscoll, Amanda J; Deloria Knoll, Maria; Hammitt, Laura L; Baggett, Henry C; Brooks, W Abdullah; Feikin, Daniel R; Kotloff, Karen L; Levine, Orin S; Madhi, Shabir A; O'Brien, Katherine L; Scott, J Anthony G; Thea, Donald M; Howie, Stephen R C; Adrian, Peter V; Ahmed, Dilruba; DeLuca, Andrea N; Ebruke, Bernard E; Gitahi, Caroline; Higdon, Melissa M; Kaewpan, Anek; Karani, Angela; Karron, Ruth A; Mazumder, Razib; McLellan, Jessica; Moore, David P; Mwananyanda, Lawrence; Park, Daniel E; Prosperi, Christine; Rhodes, Julia; Saifullah, Md; Seidenberg, Phil; Sow, Samba O; Tamboura, Boubou; Zeger, Scott L; Murdoch, David R
Antibiotic exposure and specimen volume are known to affect pathogen detection by culture. Here we assess their effects on bacterial pathogen detection by both culture and polymerase chain reaction (PCR) in children. PERCH (Pneumonia Etiology Research for Child Health) is a case-control study of pneumonia in children aged 1-59 months investigating pathogens in blood, nasopharyngeal/oropharyngeal (NP/OP) swabs, and induced sputum by culture and PCR. Antibiotic exposure was ascertained by serum bioassay, and for cases, by a record of antibiotic treatment prior to specimen collection. Inoculated blood culture bottles were weighed to estimate volume. Antibiotic exposure ranged by specimen type from 43.5% to 81.7% in 4223 cases and was detected in 2.3% of 4863 controls. Antibiotics were associated with a 45% reduction in blood culture yield and approximately 20% reduction in yield from induced sputum culture. Reduction in yield of Streptococcus pneumoniae from NP culture was approximately 30% in cases and approximately 32% in controls. Several bacteria had significant but marginal reductions (by 5%-7%) in detection by PCR in NP/OP swabs from both cases and controls, with the exception of S. pneumoniae in exposed controls, which was detected 25% less frequently compared to nonexposed controls. Bacterial detection in induced sputum by PCR decreased 7% for exposed compared to nonexposed cases. For every additional 1 mL of blood culture specimen collected, microbial yield increased 0.51% (95% confidence interval, 0.47%-0.54%), from 2% when volume was ≤1 mL to approximately 6% for ≥3 mL. Antibiotic exposure and blood culture volume affect detection of bacterial pathogens in children with pneumonia and should be accounted for in studies of etiology and in clinical management. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.
Brooks, J P; McLaughlin, M R; Adeli, A; Miles, D M
Conventional commercial broiler production involves the rearing of more than 20,000 broilers in a single confined space for approximately 6.5 wk. This environment is known for harboring pathogens and antibiotic-resistant bacteria, but studies have focused on previously established houses with mature litter microbial populations. In the current study, a set of three naive houses were followed from inception through 11 broiler flocks and monitored for ambient climatic conditions, bacterial pathogens, and antibiotic resistance. Within the first 3 wk of the first flock cycle, 100% of litter samples were positive for and , whereas was cultivation negative but PCR positive. Antibiotic resistance genes were ubiquitously distributed throughout the litter within the first flock, approaching 10 to 10 genomic units g. Preflock litter levels were approximately 10 CFU g for heterotrophic plate count bacteria, whereas midflock levels were >10 colony forming units (CFU) g; other indicators demonstrated similar increases. The influence of intrahouse sample location was minor. In all likelihood, given that preflock levels were negative for pathogens and antibiotic resistance genes and 4 to 5 Log lower than flock levels for indicators, incoming birds most likely provided the colonizing microbiome, although other sources were not ruled out. Most bacterial groups experienced a cyclical pattern of litter contamination seen in other studies, whereas microbial stabilization required approximately four flocks. This study represents a first-of-its-kind view into the time required for bacterial pathogens and antibiotic resistance to colonize and establish in naive broiler houses. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.
Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald
The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.
Truong, Quang Lam; Seo, Tae Won; Yoon, Byung-Il; Kim, Hyeon-Cheol; Han, Jeong Hee; Hahn, Tae-Wook
In 2008, 102 rodents and 24 stray cats from the areas around 9 pig farms in northeast South Korea were used to determine the prevalence of the following selected swine pathogens: ten viral pathogens [porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), rotavirus, classical swine fever virus (CSFV), porcine circovirus type 2 (PCV2), encephalomyocarditis virus (EMCV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine parvovirus (PPV), pseudorabies virus (PRV) and Japanese encephalitis virus (JEV)] and four bacterial pathogens (Brucella, Leptospira, Salmonella and Lawsonia intracellularis). In total, 1,260 tissue samples from 102 rodents and 24 stray cats were examined by specific PCR and RT-PCR assays, including tissue samples of the brain, tonsils, lungs, heart, liver, kidneys, spleen, small intestine, large intestine and mesenteric lymph nodes. The percentages of PCR-positive rodents for the porcine pathogens were as follows: 63.7% for Leptospira, 39.2% for Brucella, 6.8% for Salmonella, 15.7% for L. intracellularis, 14.7% for PCV2 and 3.9% for EMCV. The percentages of PCR-positive stray cats for the swine pathogens were as follows: 62.5% for Leptospira, 25% for Brucella, 12.5% for Salmonella, 12.5% for L. intracellularis and 4.2% for PEDV. These results may be helpful for developing control measures to prevent the spread of infectious diseases of pigs.
Kaur, Ravinder; Wischmeyer, Jareth; Morris, Matthew; Pichichero, Michael E
We compared the recovery of potential respiratory bacterial pathogens and normal flora from nasopharyngeal specimens collected from children during health and at the onset of acute otitis media (AOM) by selective direct-plating and overnight broth-enrichment. Overall, 3442 nasal wash (NW) samples collected from young children were analysed from a 10-year prospective study. NWs were cultured by (1) direct-plating to TSAII/5 % sheep blood agar and chocolate agar plates and (2) overnight broth-enrichment in BacT/ALERT SA-broth followed by plating. Standard microbiology techniques were applied to identify three dominant respiratory bacterial pathogens: Streptococcus pneumoniae (Spn), Haemophilus influenzae (Hflu) and Moraxella catarrhalis (Mcat) as well as two common nasal flora, Staphylococcus aureus (SA) and alpha-haemolytic Streptococci (AHS).Results/Key findings. Direct-plating of NW resulted in isolation of Spn from 37.8 %, Hflu from 13.6 % and Mcat from 33.2 % of samples. In comparison, overnight broth-enrichment isolated fewer Spn (30.1 %), Hflu (6.2 %) and Mcat (16.2 %) (P<0.001-0.0001). Broth-enrichment resulted in significant increased isolation of SA (6.0 %) and AHS (30.1 %) (P<0.0001). Competition between bacterial species in broth when both species were detected by direct-plating was assessed, and it was found that SA and AHS out-competed other species during broth-enrichment when samples were collected from healthy children but not during AOM. In middle ear fluids (MEF) at the onset of AOM, broth-enrichment resulted in higher recovery of Spn (+10.4 %, P<0.001), Hflu (+4.4 %, P=0.39) and Mcat (+13.5 %, <0.001). Broth-enrichment significantly reduces the accurate detection of bacterial respiratory pathogens and increases identification of SA and AHS in NW. Broth-enrichment improves detection of bacterial respiratory pathogens in MEF samples.
Maurelli, Anthony T.; Fernandez, Reinaldo E.; Bloch, Craig A.; Rode, Christopher K.; Fasano, Alessio
Plasmids, bacteriophages, and pathogenicity islands are genomic additions that contribute to the evolution of bacterial pathogens. For example, Shigella spp., the causative agents of bacillary dysentery, differ from the closely related commensal Escherichia coli in the presence of a plasmid in Shigella that encodes virulence functions. However, pathogenic bacteria also may lack properties that are characteristic of nonpathogens. Lysine decarboxylate (LDC) activity is present in ≈ 90% of E. coli strains but is uniformly absent in Shigella strains. When the gene for LDC, cadA, was introduced into Shigella flexneri 2a, virulence became attenuated, and enterotoxin activity was inhibited greatly. The enterotoxin inhibitor was identified as cadaverine, a product of the reaction catalyzed by LDC. Comparison of the S. flexneri 2a and laboratory E. coli K-12 genomes in the region of cadA revealed a large deletion in Shigella. Representative strains of Shigella spp. and enteroinvasive E. coli displayed similar deletions of cadA. Our results suggest that, as Shigella spp. evolved from E. coli to become pathogens, they not only acquired virulence genes on a plasmid but also shed genes via deletions. The formation of these ``black holes,'' deletions of genes that are detrimental to a pathogenic lifestyle, provides an evolutionary pathway that enables a pathogen to enhance virulence. Furthermore, the demonstration that cadaverine can inhibit enterotoxin activity may lead to more general models about toxin activity or entry into cells and suggests an avenue for antitoxin therapy. Thus, understanding the role of black holes in pathogen evolution may yield clues to new treatments of infectious diseases.
Grissett, G P; White, B J; Larson, R L
Bovine respiratory disease (BRD) is an economically important disease of cattle and continues to be an intensely studied topic. However, literature summarizing the time between pathogen exposure and clinical signs, shedding, and seroconversion is minimal. A structured literature review of the published literature was performed to determine cattle responses (time from pathogen exposure to clinical signs, shedding, and seroconversion) in challenge models using common BRD viral and bacterial pathogens. After review a descriptive analysis of published studies using common BRD pathogen challenge studies was performed. Inclusion criteria were single pathogen challenge studies with no treatment or vaccination evaluating outcomes of interest: clinical signs, shedding, and seroconversion. Pathogens of interest included: bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BHV-1), parainfluenza-3 virus, bovine respiratory syncytial virus, Mannheimia haemolytica, Mycoplasma bovis, Pastuerella multocida, and Histophilus somni. Thirty-five studies and 64 trials were included for analysis. The median days to the resolution of clinical signs after BVDV challenge was 15 and shedding was not detected on day 12 postchallenge. Resolution of BHV-1 shedding resolved on day 12 and clinical signs on day 12 postchallenge. Bovine respiratory syncytial virus ceased shedding on day 9 and median time to resolution of clinical signs was on day 12 postchallenge. M. haemolytica resolved clinical signs 8 days postchallenge. This literature review and descriptive analysis can serve as a resource to assist in designing challenge model studies and potentially aid in estimation of duration of clinical disease and shedding after natural pathogen exposure. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.
Ruppitsch, W; Stöger, A; Indra, A; Grif, K; Schabereiter-Gurtner, C; Hirschl, A; Allerberger, F
In a bioterrorism event a rapid tool is needed to identify relevant dangerous bacteria. The aim of the study was to assess the usefulness of partial 16S rRNA gene sequence analysis and the suitability of diverse databases for identifying dangerous bacterial pathogens. For rapid identification purposes a 500-bp fragment of the 16S rRNA gene of 28 isolates comprising Bacillus anthracis, Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis, Yersinia pestis, and eight genus-related and unrelated control strains was amplified and sequenced. The obtained sequence data were submitted to three public and two commercial sequence databases for species identification. The most frequent reason for incorrect identification was the lack of the respective 16S rRNA gene sequences in the database. Sequence analysis of a 500-bp 16S rDNA fragment allows the rapid identification of dangerous bacterial species. However, for discrimination of closely related species sequencing of the entire 16S rRNA gene, additional sequencing of the 23S rRNA gene or sequencing of the 16S-23S rRNA intergenic spacer is essential. This work provides comprehensive information on the suitability of partial 16S rDNA analysis and diverse databases for rapid and accurate identification of dangerous bacterial pathogens.
Price, Christopher T. D.; Richards, Ashley M.; Von Dwingelo, Juanita E.; Samara, Hala A.; Kwaik, Yousef Abu
Summary Legionella pneumophila, the causative agent of Legionnaires’ disease, invades and proliferates within a diverse range of free-living amoeba in the environment but upon transmission to humans the bacteria hijack alveolar macrophages. Intracellular proliferation of L. pneumophila in two evolutionarily distant hosts is facilitated by bacterial exploitation of conserved host processes that are targeted by bacterial protein effectors injected into the host cell. A key aspect of microbe-host interaction is microbial extraction of nutrients from the host but understanding of this is still limited. AnkB functions as a nutritional virulence factor and promotes host proteasomal degradation of polyubiquitinated proteins generating gratuitous levels of limiting host cellular amino acids. L. pneumophila is auxotrophic for several amino acids including cysteine, which is a metabolically preferred source of carbon and energy during intracellular proliferation, but is limiting in both amoebae and humans. We propose that synchronization of bacterial amino acids auxotrophy with the host is a driving force in pathogenic evolution and nutritional adaptation of L. pneumophila and other intracellular bacteria to life within the host cell. Understanding microbial strategies of nutrient gene