Comparison study of broth macrodilution and microdilution antifungal susceptibility tests for the filamentous fungi.

PubMed Central

Pujol, I; Guarro, J; Llop, C; Soler, L; Fernández-Ballart, J

1996-01-01

An evaluation of broth dilution antifungal susceptibility tests was performed by determining both the micro- and macrodilution MICs of amphotericin B, fluconazole, ketoconazole, 5-fluorocytosine, miconazole, and itraconazole against representative species of opportunistic hyphomycetes (Fusarium spp. and Cladosporium [Cladophialophora] spp.) and ascomycetes (Chaetomium spp.). A total of 78 strains were tested, the majority of them twice and some three times on different days. Both methods were performed according to the recommendations of the National Committee for Clinical Laboratory Standards (Document M27-P), with the exception of the temperature of incubation, which was 25 degrees C in our case. A spectrophotometric method for inoculum preparation, RPMI 1640 medium buffered with morpholinepropanesulfonic acid (pH 7.0), and an additive drug dilution procedure were used. The MICs obtained by the two methods were read after 48, 72, and 96 h of incubation for Fusarium spp. and after 72, 96, and 120 h for the remaining isolates. The kappa test was used to calculate the degree of agreement. Considering the three fungal groups together, a good agreement between the results of both tests was observed with almost all the drugs at the different incubation times. There were no cases of poor agreement. The highest level (kappa index = 1) was observed with ketoconazole at the second-day reading. These results support the further evaluation of the broth microdilution test as an alternative to the reference broth macrodilution susceptibility test. PMID:8878589

In Vitro Activities of Gemifloxacin versus Five Quinolones and Two Macrolides against 271 Spanish Isolates of Legionella pneumophila: Influence of Charcoal on Susceptibility Test Results

PubMed Central

García, M. T.; Pelaz, C.; Giménez, M. J.; Aguilar, L.

2000-01-01

The MICs at which 90% of isolates are inhibited for gemifloxacin, trovafloxacin, and grepafloxacin were low (≤0.01 μg/ml) for 271 Legionella isolates when they were determined by the broth microdilution method but increased (≥6 dilutions) when they were determined by the agar dilution method. This was due to the charcoal in the agar dilution medium, as shown by the progressive decrease in the MICs when the charcoal concentrations decreased. As free drug is the active fraction, charcoal binding should be considered. PMID:10898695

Direct Antimicrobial Susceptibility Testing of Gram-Negative Bacilli in Blood Cultures by an Electrochemical Method

PubMed Central

Huang, Ay Huey; Wu, Jiunn Jong; Weng, Yu Mei; Ding, Hwia Cheng; Chang, Tsung Chain

1998-01-01

Nonfastidious aerobic gram-negative bacilli (GNB) are commonly isolated from blood cultures. The feasibility of using an electrochemical method for direct antimicrobial susceptibility testing of GNB in positive blood cultures was evaluated. An aliquot (10 μl) of 1:10-diluted positive blood cultures containing GNB was inoculated into the Bactometer module well (bioMérieux Vitek, Hazelwood, Mo.) containing 1 ml of Mueller-Hinton broth supplemented with an antibiotic. Susceptibility tests were performed in a breakpoint broth dilution format, with the results being categorized as resistant, intermediate, or susceptible. Seven antibiotics (ampicillin, cephalothin, gentamicin, amikacin, cefamandole, cefotaxime, and ciprofloxacin) were used in this study, with each agent being tested at the two interpretive breakpoint concentrations. The inoculated modules were incubated at 35°C, and the change in impedance in each well was continuously monitored for 24 h by the Bactometer. The MICs of the seven antibiotics for each blood isolate were also determined by the standardized broth microdilution method. Of 146 positive blood cultures (1,022 microorganism-antibiotic combinations) containing GNB tested by the direct method, the rates of very major, major, and minor errors were 0, 1.1, and 2.5%, respectively. The impedance method was simple; no centrifugation, preincubation, or standardization of the inocula was required, and the susceptibility results were normally available within 3 to 6 h after inoculation. The rapid method may allow proper antimicrobial treatment almost 30 to 40 h before the results of the standard methods are available. PMID:9738038

THE ANTIBACTERIAL PROPERTIES OF SULFUR

PubMed Central

Weld, Julia T.; Gunther, Anne

1947-01-01

1. Saturated solutions of sulfur in alcohol (alcohol-sulfur) when diluted with broth are inhibitory to the growth of various Gram-positive bacteria and to C. hominis. By an arbitrary method of unitage with S. aureus as the test organism, our alcohol-sulfur contains 1,600 to 2,000 units per cc. and one unit contains between 0.24 and 0.34 gamma sulfur. The activity of a preparation is in general directly proportional to its sulfur content. 2. Solutions of sulfur in carbowax (carbowax-sulfur) when diluted with broth are likewise inhibitory to the growth of various Gram-positive bacteria and to C. hominis. When S. aureus is used as test organism, 1 unit contains between 0.1 and 0.2 gamma sulfur. The activity of these preparations is also in general directly proportional to their sulfur content. 3. Carbowax-sulfur when incorporated in agar in 1–500 to 1–2,000 dilution inhibits the growth of various Gram-positive aerobic and anaerobic bacteria, C. hominis, and certain dermatophytes. 4. Our experiments appear to show that both alcohol-sulfur and carbowax-sulfur owe their inhibitory properties to the sulfur particles that are dispersed throughout the medium when these sulfur preparations are diluted with broth. The inhibitory effect of these particles may or may not be due to a combination of the sulfur particles with substances in the medium in which they are suspended. 5. Evidence suggests that the activity of both alcohol-sulfur and carbowax-sulfur is due to sulfur in the same form. The inhibitory effect is characterized by prolonged bacteriostasis with similar activity over a wide range of dilutions. There is no evidence of true bactericidal action even with the highest concentrations used. PMID:19871634

Antibacterial activity of Tribulus terrestris and its synergistic effect with Capsella bursa-pastoris and Glycyrrhiza glabra against oral pathogens: an in-vitro study

PubMed Central

Soleimanpour, Saman; Sedighinia, Fereshteh Sadat; Safipour Afshar, Akbar; Zarif, Reza; Ghazvini, Kiarash

2015-01-01

Objective: In this study, antimicrobial activities of an ethanol extract of Tribulus terrestris aloneand in combination with Capsella bursa-pastoris and Glycyrrhiza glabra were examined in vitro against six pathogens namely Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus, Enterococcus faecalis Staphylococcus aureus, and Escherichia coli. Materials and methods: Antibacterial activities of the extracts were examined using disc and well diffusion methods and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanol extracts were determined against these microorganisms using agar and broth dilution methods. Chlorhexidine was used as positive control. Results: Tribulus terrestris extract exhibited good antibacterial activity against all bacteria. Antibacterial activity of mixed extract was evaluated and exhibited that mixed extract was more effective against all bacteria than any of the cases alone which indicates the synergistic effect between these three extracts (p˂0.05). No strain showed resistance against these extracts. In agar dilution, Tribulus terrestris exhibited MIC values ranging from 35.0 to 20.0 mg/ml and mixed extract showed MIC values ranging from 12.5 to 5.0 mg/ml. The results of broth dilution method were consistent with the findings of the agar dilution method. Conclusion: This in-vitro study was a preliminary evaluation of antibacterial activity of the plants. It provided scientific evidence to support uses of T. terrestris and its mixture with C. bursa-pastoris and G. glabra for the treatment of oral infections. In-vivo studies are also required to better evaluate the effect of these extracts. PMID:26101754

Comparison of methods for recovery of Escherichia coli and Staphylococcus aureus from seeded laundry fabrics.

PubMed Central

Cody, H J; Smith, P F; Blaser, M J; LaForce, F M; Wang, W L

1984-01-01

To assess the effect of laundry procedures on fabric-associated bacteria, a standard method of enumeration is needed. We evaluated six methods for enumeration of Escherichia coli and Staphylococcus aureus seeded (10(2) and 10(5) CFU/100 cm2 of fabric area) onto sterilized hospital sheets and terry . Two methods involved maceration of seeded swatches in broth followed by passage of the broth through a 0.45-micron-pore-size, 47-mm-diameter filter membrane. Three methods involved agitation of seeded swatches in broth with a paint shaker and membrane filtration of the broth to recover eluted bacterial cells, and the final method involved direct enumeration of cells on fabrics by overlaying seeded swatches with agar containing triphenyltetrazolium chloride as an indicator. The most convenient recovery method employed a 90-s agitation followed by serial dilution of broths and membrane filtration. This method provided 44/57% (low seed/high seed) recovery of E. coli from sheets and 133/31% from terry and 34/74% recovery of S. aureus from sheets and 58/57% from terry . Although maceration provided similar recovery of E. coli and S. aureus, it is a less-practical method. The direct enumeration method was ineffective for enumerating gram-positive bacteria. We conclude that either the agitation or maceration method used enumerated the seeded bacteria to within 1 log10 of their expected number and can be used to assess the bactericidal effectiveness of various steps in the laundering process. PMID:6378092

Antibacterial activity of Tribulus terrestris and its synergistic effect with Capsella bursa-pastoris and Glycyrrhiza glabra against oral pathogens: an in-vitro study.

PubMed

Soleimanpour, Saman; Sedighinia, Fereshteh Sadat; Safipour Afshar, Akbar; Zarif, Reza; Ghazvini, Kiarash

2015-01-01

In this study, antimicrobial activities of an ethanol extract of Tribulus terrestris aloneand in combination with Capsella bursa-pastoris and Glycyrrhiza glabra were examined in vitro against six pathogens namely Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus, Enterococcus faecalis Staphylococcus aureus, and Escherichia coli. Antibacterial activities of the extracts were examined using disc and well diffusion methods and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanol extracts were determined against these microorganisms using agar and broth dilution methods. Chlorhexidine was used as positive control. Tribulus terrestris extract exhibited good antibacterial activity against all bacteria. Antibacterial activity of mixed extract was evaluated and exhibited that mixed extract was more effective against all bacteria than any of the cases alone which indicates the synergistic effect between these three extracts (p˂0.05). No strain showed resistance against these extracts. In agar dilution, Tribulus terrestris exhibited MIC values ranging from 35.0 to 20.0 mg/ml and mixed extract showed MIC values ranging from 12.5 to 5.0 mg/ml. The results of broth dilution method were consistent with the findings of the agar dilution method. This in-vitro study was a preliminary evaluation of antibacterial activity of the plants. It provided scientific evidence to support uses of T. terrestris and its mixture with C. bursa-pastoris and G. glabra for the treatment of oral infections. In-vivo studies are also required to better evaluate the effect of these extracts.

Analytical Method for the Detection of Residual Active Ingredients Found in Neutralized Suspensions of Antimicrobial Products.

PubMed

Kamel, Alaa; Tomasino, Stephen F

2017-03-01

An analytical method for determining the presence and levels of residual active ingredients found in neutralized suspensions of phenolic and quaternary ammonium salt-based antimicrobial products was developed using solid-phase extraction in combination with LC-tandem MS. A single-laboratory validation of the method was performed at three concentration levels for the quaternary ammonium compounds (also referred to as benzalkonium chlorides or BACs) and the phenols in the presence of letheen broth neutralizer at 2.5 and 2.75 μg/mL, respectively, as well as at dilutions of 1:10 and 1:100 in those concentrations. The method's lowest LODs were 0.005 μg/g for BACs and 0.006 μg/g for phenols. The average recovery of the fortified samples for both active ingredients ranged between 80 and 124%, and RSDs were generally <20%. In a related study, the effectiveness of letheen broth with and without sodium thiosulfate was evaluated as a neutralizer for sodium hypochlorite. The results showed that letheen broth without sodium thiosulfate neutralizes chlorine concentrations up to 60 ppm, and that 200 μg sodium thiosulfate are required to neutralize a 72 ppm concentrated chlorine solution in letheen broth.

Methods for broth dilution susceptibility testing of bacteria isolated from aquatic animals; approved guideline-second edition

USDA-ARS?s Scientific Manuscript database

Antimicrobial susceptibility testing is recommended to determine which antimicrobial agents should be considered for treating a bacterial pathogen. Many bacteria that cause disease in aquatic animals require growth conditions that vary substantially from routine terrestrial pathogens. It has thus ...

In vitro antagonistic growth effects of Lactobacillus fermentum and lactobacillus salivarius and their fermentative broth on periodontal pathogens.

PubMed

Chen, Ling-Ju; Tsai, Hsiu-Ting; Chen, Wei-Jen; Hsieh, Chu-Yang; Wang, Pi-Chieh; Chen, Chung-Shih; Wang, Lina; Yang, Chi-Chiang

2012-10-01

As lactobacilli possess an antagonistic growth property, these bacteria may be beneficial as bioprotective agents for infection control. However, whether the antagonistic growth effects are attributed to the lactobacilli themselves or their fermentative broth remains unclear. The antagonistic growth effects of Lactobacillus salivarius and Lactobacillus fermentum as well as their fermentative broth were thus tested using both disc agar diffusion test and broth dilution method, and their effects on periodontal pathogens, including Streptococcus mutans, Streptococcus sanguis, and Porphyromonas gingivalis in vitro at different concentrations and for different time periods were also compared. Both Lactobacillus salivarius and Lactobacillus fermentum and their concentrated fermentative broth were shown to inhibit significantly the growth of Streptococcus mutans, Streptococcus sanguis, and Porphyromonas gingivalis, although different inhibitory effects were observed for different pathogens. The higher the counts of lactobacilli and the higher the folds of concentrated fermentative broth, the stronger the inhibitory effects are observed. The inhibitory effect is demonstrated to be dose-dependent. Moreover, for the lactobacilli themselves, Lactobacillus fermentum showed stronger inhibitory effects than Lactobacillus salivarius. However, the fermentative broth of Lactobacillus fermentum showed weaker inhibitory effects than that of Lactobacillus salivarius. These data suggested that lactobacilli and their fermentative broth exhibit antagonistic growth activity, and consumption of probiotics or their broth containing lactobacilli may benefit oral health.

Comparison of agar dilution and antibiotic gradient strip test with broth microdilution for susceptibility testing of swine Brachyspira species.

PubMed

Mirajkar, Nandita S; Gebhart, Connie J

2016-03-01

Production-limiting diseases in swine caused by Brachyspira are characterized by mucohemorrhagic diarrhea (B. hyodysenteriae and "B. hampsonii") or mild colitis (B. pilosicoli), while B. murdochii is often isolated from healthy pigs. Emergence of novel pathogenic Brachyspira species and strains with reduced susceptibility to commonly used antimicrobials has reinforced the need for standardized susceptibility testing. Two methods are currently used for Brachyspira susceptibility testing: agar dilution (AD) and broth microdilution (BMD). However, these tests have primarily been used for B. hyodysenteriae and rarely for B. pilosicoli. Information on the use of commercial susceptibility testing products such as antibiotic gradient strips is lacking. Our main objective was to validate and compare the susceptibility results, measured as the minimum inhibitory concentration (MIC), of 6 antimicrobials for 4 Brachyspira species (B. hyodysenteriae, "B. hampsonii", B. pilosicoli, and B. murdochii) by BMD and AD (tiamulin, valnemulin, lincomycin, tylosin, and carbadox) or antibiotic gradient strip (doxycycline) methods. In general, the results of a high percentage of all 4 Brachyspira species differed by ±1 log2 dilution or less by BMD and AD for tiamulin, valnemulin, lincomycin, and tylosin, and by BMD and antibiotic gradient strip for doxycycline. The carbadox MICs obtained by BMD were 1-5 doubling dilutions different than those obtained by AD. BMD for Brachyspira was quicker to perform with less ambiguous interpretation of results when compared with AD and antibiotic gradient strip methods, and the results confirm the utility of BMD in routine diagnostics. © 2016 The Author(s).

Irreproducible and uninterpretable Polymyxin B MICs for Enterobacter cloacae and Enterobacter aerogenes.

PubMed

Landman, David; Salamera, Julius; Quale, John

2013-12-01

Carbapenem-resistant Enterobacter species are emerging nosocomial pathogens. As with most multidrug-resistant Gram-negative pathogens, the polymyxins are often the only therapeutic option. In this study involving clinical isolates of E. cloacae and E. aerogenes, susceptibility testing methods with polymyxin B were analyzed. All isolates underwent testing by the broth microdilution (in duplicate) and agar dilution (in duplicate) methods, and select isolates were examined by the Etest method. Selected isolates were also examined for heteroresistance by population analysis profiling. Using a susceptibility breakpoint of ≤2 μg/ml, categorical agreement by all four dilution tests (two broth microdilution and two agar dilution) was achieved in only 76/114 (67%) of E. cloacae isolates (65 susceptible, 11 resistant). Thirty-eight (33%) had either conflicting or uninterpretable results (multiple skip wells, i.e., wells that exhibit no growth although growth does occur at higher concentrations). Of the 11 consistently resistant isolates, five had susceptible MICs as determined by Etest. Heteroresistant subpopulations were detected in eight of eight isolates tested, with greater percentages in isolates with uninterpretable MICs. For E. aerogenes, categorical agreement between the four dilution tests was obtained in 48/56 (86%), with conflicting and/or uninterpretable results in 8/56 (14%). For polymyxin susceptibility testing of Enterobacter species, close attention must be paid to the presence of multiple skip wells, leading to uninterpretable results. Susceptibility also should not be assumed based on the results of a single test. Until the clinical relevance of skip wells is defined, interpretation of polymyxin susceptibility tests for Enterobacter species should be undertaken with extreme caution.

Irreproducible and Uninterpretable Polymyxin B MICs for Enterobacter cloacae and Enterobacter aerogenes

PubMed Central

Landman, David; Salamera, Julius

2013-01-01

Carbapenem-resistant Enterobacter species are emerging nosocomial pathogens. As with most multidrug-resistant Gram-negative pathogens, the polymyxins are often the only therapeutic option. In this study involving clinical isolates of E. cloacae and E. aerogenes, susceptibility testing methods with polymyxin B were analyzed. All isolates underwent testing by the broth microdilution (in duplicate) and agar dilution (in duplicate) methods, and select isolates were examined by the Etest method. Selected isolates were also examined for heteroresistance by population analysis profiling. Using a susceptibility breakpoint of ≤2 μg/ml, categorical agreement by all four dilution tests (two broth microdilution and two agar dilution) was achieved in only 76/114 (67%) of E. cloacae isolates (65 susceptible, 11 resistant). Thirty-eight (33%) had either conflicting or uninterpretable results (multiple skip wells, i.e., wells that exhibit no growth although growth does occur at higher concentrations). Of the 11 consistently resistant isolates, five had susceptible MICs as determined by Etest. Heteroresistant subpopulations were detected in eight of eight isolates tested, with greater percentages in isolates with uninterpretable MICs. For E. aerogenes, categorical agreement between the four dilution tests was obtained in 48/56 (86%), with conflicting and/or uninterpretable results in 8/56 (14%). For polymyxin susceptibility testing of Enterobacter species, close attention must be paid to the presence of multiple skip wells, leading to uninterpretable results. Susceptibility also should not be assumed based on the results of a single test. Until the clinical relevance of skip wells is defined, interpretation of polymyxin susceptibility tests for Enterobacter species should be undertaken with extreme caution. PMID:24088860

Detection of antimicrobial activity of banana peel (Musa paradisiaca L.) on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans: An in vitro study.

PubMed

Kapadia, Suraj Premal; Pudakalkatti, Pushpa S; Shivanaikar, Sachin

2015-01-01

Banana is used widely because of its nutritional values. In past, there are studies that show banana plant parts, and their fruits can be used to treat the human diseases. Banana peel is a part of banana fruit that also has the antibacterial activity against microorganisms but has not been studied extensively. Since, there are no studies that relate the antibacterial activity of banana peel against periodontal pathogens. Hence, the aim of this study is to determine the antimicrobial activity of banana peel extract on Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans). Standard strains of P. gingivalis and A. actinomycetemcomitans were used in this study which was obtained from the in-house bacterial bank of Department of Molecular Biology and Immunology at Maratha Mandal's Nathajirao G. Halgekar Institute of Dental Sciences and Research Centre. The banana peel extract was prepared, and the antibacterial activity was assessed using well agar diffusion method and minimum inhibitory concentration was assessed using serial broth dilution method. In the current study, both the tested microorganisms showed antibacterial activity. In well diffusion method, P. gingivalis and A. actinomycetemcomitans showed 15 mm and 12 mm inhibition zone against an alcoholic extract of banana peel, respectively. In serial broth dilution method P. gingivalis and A. actinomycetemcomitans were sensitive until 31.25 μg/ml dilutions. From results of the study, it is suggested that an alcoholic extract of banana peel has antimicrobial activity against P. gingivalis and A. actinomycetemcomitans.

Citrus-derived oils inhibit Satphylococcus aureus growth and alter its interaction with bovine mammary cells

USDA-ARS?s Scientific Manuscript database

This experiment examined the effects of cold-pressed, terpeneless citrus oil (CDO) on growth of Staphylococcus aureus, which a major cause of contagious bovine mastitis, and invasion of epithelial cells as modeled with bovine mammary cells (MAC-T). The broth dilution method (Muthaiyan et al., 2012)...

Detection of antimicrobial activity of banana peel (Musa paradisiaca L.) on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans: An in vitro study

PubMed Central

Kapadia, Suraj Premal; Pudakalkatti, Pushpa S.; Shivanaikar, Sachin

2015-01-01

Introduction and Aim: Banana is used widely because of its nutritional values. In past, there are studies that show banana plant parts, and their fruits can be used to treat the human diseases. Banana peel is a part of banana fruit that also has the antibacterial activity against microorganisms but has not been studied extensively. Since, there are no studies that relate the antibacterial activity of banana peel against periodontal pathogens. Hence, the aim of this study is to determine the antimicrobial activity of banana peel extract on Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans). Material and Methods: Standard strains of P. gingivalis and A. actinomycetemcomitans were used in this study which was obtained from the in-house bacterial bank of Department of Molecular Biology and Immunology at Maratha Mandal's Nathajirao G. Halgekar Institute of Dental Sciences and Research Centre. The banana peel extract was prepared, and the antibacterial activity was assessed using well agar diffusion method and minimum inhibitory concentration was assessed using serial broth dilution method. Results: In the current study, both the tested microorganisms showed antibacterial activity. In well diffusion method, P. gingivalis and A. actinomycetemcomitans showed 15 mm and 12 mm inhibition zone against an alcoholic extract of banana peel, respectively. In serial broth dilution method P. gingivalis and A. actinomycetemcomitans were sensitive until 31.25 μg/ml dilutions. Conclusion: From results of the study, it is suggested that an alcoholic extract of banana peel has antimicrobial activity against P. gingivalis and A. actinomycetemcomitans. PMID:26681854

Volatile flavor constituents in the pork broth of black-pig.

PubMed

Zhao, Jian; Wang, Meng; Xie, Jianchun; Zhao, Mengyao; Hou, Li; Liang, Jingjing; Wang, Shi; Cheng, Jie

2017-07-01

Pork of black-pig in China is well known for its quality and preferred by consumers. However, there is a lack of research on its flavors. By solvent assisted flavor evaporation combined with GC-MS, 104 volatile compounds in the stewed pork broth of black-pig were identified with the dominant amounts of fatty acids, alcohols, and esters. By aroma extract dilution analysis-GC-O method, 27 odor-active compounds were characterized, including 2-methyl-3-furanthiol, 3-(methylthio)propanal, 2-furfurylthiol, γ-decalactone, nonanal, (E)-2-nonenal, and (E,E)-2,4-decadienal that had high FD factors. Compared to the common white-pig, the aroma compounds in both pork broths were almost the same, but the aroma profile of potent odorants for the black-pig pork broth showed less fatty and more roasted notes, which were partially attributed to the higher monounsaturated fatty acids and lower polyunsaturated fatty acids in meat. With aid of authentic chemicals and selected reaction monitoring mode of GC-MS/MS, 19 aroma compounds were quantitated. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pre-treatment step with Leuconostoc mesenteroides or L. pseudomesenteroides strains removes furfural from Zymomonas mobilis ethanolic fermentation broth

USDA-ARS?s Scientific Manuscript database

Furfural (furan-2-carboxaldehyde), formed during dilute acid hydrolysis of biomass, is an inhibitor of growth and ethanol production by Zymomonas mobilis. The present study used a biological pre-treatment to reduce that amount of furfural in a model biofuel fermentation broth. The pre-treatment in...

Antimicrobial effects of Thai medicinal plants against acne-inducing bacteria.

PubMed

Chomnawang, Mullika Traidej; Surassmo, Suvimol; Nukoolkarn, Veena S; Gritsanapan, Wandee

2005-10-03

Propionibacterium acnes and Staphylococcus epidermidis have been recognized as pus-forming bacteria triggering an inflammation in acne. The present study was conducted to evaluate antimicrobial activities of Thai medicinal plants against these etiologic agents of acne vulgaris. Crude extracts were tested for antimicrobial activities by disc diffusion and broth dilution methods. The results from the disc diffusion method showed that 13 medicinal plants could inhibit the growth of Propionibacterium acnes. Among those, Senna alata, Eupatorium odoratum, Garcinia mangostana, and Barleria lupulina had strong inhibitory effects. Based on a broth dilution method, the Garcinia mangostana extract had the greatest antimicrobial effect. The MIC values were the same (0.039 mg/ml) for both bacterial species and the MBC values were 0.039 and 0.156 mg/ml against Propionibacterium acnes and Staphylococcus epidermidis, respectively. In bioautography assay, the Garcinia mangostana extract produced strong inhibition zones against Propionibacterium acnes. Antimicrobial activity from fractions of column chromatography revealed one of the active compounds in Garcinia mangostana could be mangostin, a xanthone derivative. Taken together, our data indicated that Garcinia mangostana had a strong inhibitory effect on Propionibacterium acnes and Staphylococcus epidermidis. Therefore, this plant would be an interesting topic for further study and possibly for an alternative treatment for acne.

Polymyxin B Etest® compared with gold-standard broth microdilution in carbapenem-resistant Enterobacteriaceae exhibiting a wide range of polymyxin B MICs.

PubMed

Kulengowski, B; Ribes, J A; Burgess, D S

2018-04-16

Polymyxins have been revitalized to combat carbapenem-resistant Enterobacteriaceae (CRE). However, evaluating the activity of these agents by traditional broth dilution methods is not practical for busy clinical laboratories. We compared polymyxin B activity using two quantitative susceptibility testing methods, Etest ® and broth microdilution (BMD), against CRE isolates from patients at an academic medical centre. Polymyxin B activity against 70 CRE clinical isolates was determined by Etest ® according to the manufacturer and by BMD according to CLSI guidelines. Pseudomonas aeruginosa ATCC ® 27853 and Escherichia coli NCTC 13846 served as quality control strains. The EUCAST colistin susceptibility breakpoint of Enterobacteriaceae (≤2 mg/L) was used. Essential agreement was isolates with an MIC within 1 log 2 dilution over total isolates. Categorical agreement was number of isolates in the same susceptibility category (susceptible or resistant) over total isolates. Major and very major error rates were calculated using number of susceptible and number of resistant isolates, respectively, as the denominator. McNemar's test was used for determining a difference in susceptibility between methods. The CRE isolates were primarily Klebsiella spp. (49%) and Enterobacter spp. (36%). Polymyxin B susceptibility was significantly higher by Etest ® compared with BMD (97% versus 77%; p 0.0001). Categorical agreement was 80%, but essential agreement was low (10%). False non-susceptibility was never observed by Etest ® (BMD reference), but the very major errors were high (88%). Etest ® reporting of false susceptibility may result in inappropriate antibiotic use and treatment failure clinically. We do not recommend using Etest ® for polymyxin B susceptibility testing for routine patient care. Copyright © 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Comparative evaluation of the efficacy of a herbal mouthwash and chlorhexidine mouthwash on select periodontal pathogens: An in vitro and ex vivo study

PubMed Central

Pathan, Multazim Muradkhan; Bhat, Kishore Gajanan; Joshi, Vinayak Mahableshwar

2017-01-01

Background: Several herbal mouthwash and herbal extracts have been tested in vitro and in vivo in search of a suitable adjunct to mechanical therapy for long-term use. In this study, we aimed to look at the antimicrobial effect of the herbal mouthwash and chlorhexidine (CHX) mouthwash on select organisms in in vitro test and an ex vivo model. Materials and Methods: The antimicrobial effects were determined against standard strains of bacteria that are involved in different stages of periodontal diseases. The in vitro tests included determination of minimum inhibitory concentration (MIC) using broth dilution and agar diffusion. In the ex vivo part of the study supragingival dental plaque were obtained from 20 periodontally healthy adult volunteers. Descriptive analysis was done for the entire quantitative and qualitative variable recorded. Results: The MIC by broth dilution method found no statistically significant difference between the mouthwashes. The agar dilution method showed CHX was more effective as compared to the herbal mouthwash against standard strains of Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans. However, no difference was observed between the mouthwashes for Porphyromonas, Pseudomonas aeruginosa, and Fusobacterium nucleatum. The ex vivo results conclude that none of the selected mouthwashes were statistically significantly different from each other. Conclusion: In the present study, CHX showed higher levels of antimicrobial action than the herbal mouthwash against bacterial species. The results reinforce the earlier findings that the in vitro testing is sensitive to methods and due diligence is needed when extrapolating the data for further use. However, long-term use and in vivo effectiveness against the periopathogens need to be tested in well-planned clinical trials. PMID:29456300

Comparison of the EUCAST and CLSI Broth Microdilution Methods for Testing Isavuconazole, Posaconazole, and Amphotericin B against Molecularly Identified Mucorales Species

PubMed Central

Singh, Pradeep Kumar; Kathuria, Shallu

2015-01-01

We compared EUCAST and CLSI antifungal susceptibility testing (AFST) methods for triazoles and amphotericin B against 124 clinical Mucorales isolates. The EUCAST method yielded MIC values 1- to 3-fold dilutions higher than those of the CLSI method for amphotericin B. The essential agreements between the two methods for triazoles were high, i.e., 99.1% (voriconazole), 98.3% (isavuconazole), and 87% (posaconazole), whereas it was significantly lower for amphotericin B (66.1%). Strategies for harmonization of the two methods for Mucorales AFST are warranted. PMID:26438489

Commercial broth microdilution panel validation and reproducibility trials for NVP PDF-713 (LBM 415), a novel inhibitor of bacterial peptide deformylase.

PubMed

Fritsche, T R; Moet, G J; Jones, R N

2004-09-01

NVP PDF-713 (LBM 415) is a peptide deformylase inhibitor being progressed into clinical trials. Dry-form broth microdilution panels of NVP PDF-713 were compared to reference MIC panels of 552 recent clinical isolates. Most (99.2%) dry-form MIC results were within +/- 1 log(2) dilution of the reference panel MICs. Of the bacteria tested, Streptococcus pneumoniae and Haemophilus influenzae showed a bias towards higher and lower MICs, respectively. Same-day and between-day reproducibility tests showed that 98.9% and 96.7% of MIC values, respectively, were within +/- 1 log(2) dilution step, thereby demonstrating a high degree of reliability of the dry-form MIC product for clinical studies.

[Assessment of two DNA extraction methods to amplify the pneumolysin gene (PLY) from blood culture samples of Streptococcus pneumoniae].

PubMed

Hernández, Carolina; Durán, Claudia; Ulloa, María Teresa; Prado, Valeria

2004-05-01

Streptococcus pneumoniae is a common etiologic agent of invasive respiratory infections among children under 5 years of age and older adults. Isolation rates of S. pneumoniae by traditional culture techniques are low. To study the sensitivity and specificity of two different DNA extraction methods to amplify the ply gene, applied to three different types of blood culture broths, experimentally inoculated with S. pneumoniae. DNA was extracted from the cultures using an organic method or a technique that consists in dilution, washing with NaOH and concentration of the sample. This was followed by PCR amplification of a 355 pb fragment of the pneumolysin gene (ply). The organic DNA extraction method inhibited the PCR reaction at all concentrations studied (0.6 to 10(6) colony forming units/mL). Using the NaOH extraction, ply gene amplification was positive in all three blood culture broths, but only at concentrations of 10(3) colony forming units/mL, or higher. Using the same DNA extraction method, PCR was negative when the broths were inoculated with seven other related bacterial species, which results in a 100% specificity. Detection of S. pneumoniae by amplification of ply gene from blood cultures using the protocol of NaOH for DNA extraction is specific and provides results in a short lapse. However, the diagnostic sensitivity is not optimal, which limits its clinical use.

Comparison of the EUCAST and CLSI Broth Microdilution Methods for Testing Isavuconazole, Posaconazole, and Amphotericin B against Molecularly Identified Mucorales Species.

PubMed

Chowdhary, Anuradha; Singh, Pradeep Kumar; Kathuria, Shallu; Hagen, Ferry; Meis, Jacques F

2015-12-01

We compared EUCAST and CLSI antifungal susceptibility testing (AFST) methods for triazoles and amphotericin B against 124 clinical Mucorales isolates. The EUCAST method yielded MIC values 1- to 3-fold dilutions higher than those of the CLSI method for amphotericin B. The essential agreements between the two methods for triazoles were high, i.e., 99.1% (voriconazole), 98.3% (isavuconazole), and 87% (posaconazole), whereas it was significantly lower for amphotericin B (66.1%). Strategies for harmonization of the two methods for Mucorales AFST are warranted. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Antimicrobial Activity of Emilia sonchifolia DC., Tridax procumbens L. and Vernonia cinerea L. of Asteracea Family: Potential as Food Preservatives.

PubMed

Yoga Latha, L; Darah, I; Sasidharan, S; Jain, K

2009-09-01

Chemical preservatives have been used in the food industry for many years. However, with increased health concerns, consumers prefer additive-free products or food preservatives based on natural products. This study evaluated antimicrobial activities of extracts from Emilia sonchifolia L. (Common name: lilac tassel flower), Tridax procumbens L. (Common name: tridax daisy) and Vernonia cinerea L. (Common name: Sahadevi), belonging to the Asteracea family, to explore their potential for use against general food spoilage and human pathogens so that new food preservatives may be developed. Three methanol extracts of these plants were tested in vitro against 20 bacterial species, 3 yeast species, and 12 filamentous fungi by the agar diffusion and broth dilution methods. The V. cinerea extract was found to be most effective against all of the tested organisms and the methanol fraction showed the most significant (p < 0.05) antimicrobial activity among all the soluble fractions tested. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 1.56 to 100.00mg/mL. The MIC of methanol fraction was the lowest in comparison to the other four extracts. The study findings indicate that bioactive natural products from these plants may be isolated for further testing as leads in the development of new pharmaceuticals in food preservation as well as natural plant-based medicine.

Component Analysis of Multipurpose Contact Lens Solutions To Enhance Activity against Pseudomonas aeruginosa and Staphylococcus aureus

PubMed Central

Lin, Leo; Kim, Janie; Chen, Hope; Kowalski, Regis

2016-01-01

More than 125 million people wear contact lenses worldwide, and contact lens use is the single greatest risk factor for developing microbial keratitis. We tested the antibacterial activity of multipurpose contact lens solutions and their individual component preservatives against the two most common pathogens causing bacterial keratitis, Pseudomonas aeruginosa and Staphylococcus aureus. The in vitro antibacterial activity of five multipurpose contact lens solutions (Opti-Free GP, Boston Simplus, Boston Advance, Menicare GP, and Lobob) was assayed by the standard broth dilution method. Synergy between the preservative components found in the top performing solutions was assayed using checkerboard and time-kill assays. The ISO 14729 criteria and the standard broth dilution method were used to define an optimized contact lens solution formulation against a clinical panel of drug-susceptible and drug-resistant P. aeruginosa and S. aureus strains. Preservatives with the biguanide function group, chlorhexidine and polyaminopropylbiguanide (PAPB), had the best antistaphylococcal activity, while EDTA was the best antipseudomonal preservative. The combination of chlorhexidine and EDTA had excellent synergy against P. aeruginosa. A solution formulation containing chlorhexidine (30 ppm), PAPB (5 ppm), and EDTA (5,000 ppm) had three to seven times more antipseudomonal activity than anything available to consumers today. A multipurpose contact lens solution containing a combination of chlorhexidine, PAPB, and EDTA could help to reduce the incidence of microbial keratitis for contact lens users worldwide. PMID:27139484

Potency of marbofloxacin for pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida: Comparison of growth media.

PubMed

Dorey, L; Hobson, S; Lees, P

2017-04-01

Pharmacodynamic properties of marbofloxacin were established for six isolates each of the pig respiratory tract pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Three in vitro indices of potency were determined; Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Mutant Prevention Concentration (MPC). For MIC determination Clinical Laboratory Standards Institute guidelines were modified in three respects: (1) comparison was made between two growth media, an artificial broth and pig serum; (2) a high inoculum count was used to simulate heavy clinical bacteriological loads; and (3) five overlapping sets of two-fold dilutions were used to improve accuracy of determinations. Similar methods were used for MBC and MPC estimations. MIC and MPC serum:broth ratios for A. pleuropneumoniae were 0.79:1 and 0.99:1, respectively, and corresponding values for P. multocida were 1.12:1 and 1.32:1. Serum protein binding of marbofloxacin was 49%, so that fraction unbound (fu) serum MIC values were significantly lower than those predicted by correction for protein binding; fu serum:broth MIC ratios were 0.40:1 (A. pleuropneumoniae) and 0.50:1 (P. multocida). For broth, MPC:MIC ratios were 13.7:1 (A. pleuropneumoniae) and 14.2:1 (P. multocida). Corresponding ratios for serum were similar, 17.2:1 and 18.8:1, respectively. It is suggested that, for dose prediction purposes, serum data might be preferable to potency indices measured in broths. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polymyxin B Etest Fails to Distinguish Carbapenem-resistant Enterobacteriaceae with Elevated Polymyxin B MICs

PubMed Central

Kulengowski, Brandon; Brignola, Matthew; Gallagher, Chanah; Rutter, W Cliff; Ribes, Julie A; Burgess, David S

2017-01-01

Abstract Background Polymyxins are being revitalized to combat carbapenem-resistant Enterobacteriaceae (CRE). However, evaluating the activity of these agents by traditional broth dilution methods is not practical for busy clinical laboratories. We compared polymyxin B (PMB) activity utilizing two quantitative susceptibility testing methods, Etest® and broth microdilution (BMD), against CRE isolates from patients at an academic medical center. Methods PMB activity against 70 recent CRE clinical isolates was determined by BMD and Etest® according to CLSI guidelines. P. aeruginosa ATCC® 27853 was used as a quality control strain. The CLSI PMB susceptibility breakpoint of non-fermenting gram-negative bacteria (<2 mg/L) was used. Essential agreement between methods was defined as an MIC measured within 1 log2 dilution. Categorical agreement was defined between methods as classification of isolates in the same susceptibility category (susceptible or resistant). Major and very major error rates were calculated, and McNemar’s test was used for determining a difference between methods. Results CRE isolates were primarily Enterobacter spp. (43%), followed by K. pneumoniae (41%) and E. coli (9%). Essential agreement between testing methods was low (9%), but categorical agreement was 81% (P = 0.0002). Although false non-susceptibility was never observed by Etest® (BMD as reference), the rate of very major errors by Etest® was high (19%). Etest® miscalled 87% of PMB-resistant CRE. Conclusion Etest® reporting of false susceptibility may result in inappropriate antibiotic utilization and treatment failure clinically. We do not recommend using Etest® for PMB susceptibility testing for routine patient care. Disclosures All authors: No reported disclosures.

Antimicrobial activity of honey from the stingless bee Trigona carbonaria determined by agar diffusion, agar dilution, broth microdilution and time-kill methodology.

PubMed

Boorn, K L; Khor, Y-Y; Sweetman, E; Tan, F; Heard, T A; Hammer, K A

2010-05-01

The aim of this study was to determine the spectrum of antimicrobial activity of 11 samples of stingless bee honey compared to medicinal, table and artificial honeys. Activity was assessed by agar diffusion, agar dilution, broth microdilution and time-kill viability assays. By agar dilution, minimum inhibitory concentration (MIC) ranges were 4% to >10% (w/v) for Gram-positive bacteria, 6% to >16% (w/v) for Gram-negative bacteria and 6% to >10% (w/v) for Candida spp. By broth microdilution, all organisms with the exception of Candida albicans and Candida glabrata were inhibited at 3 log for Pseudomonas aeruginosa and <1 log for C. albicans. Similar treatment with each control honey resulted in decreases of <1 log for all organisms. Stingless bee honey has broad-spectrum antibacterial activity although activity against Candida was limited. Stingless bee honey samples varied in activity and the basis for this remains to be determined. Stingless bee honey had similar activity to medicinal honey and may therefore have a role as a medicinal agent.

Effects of Urine Matrix and pH on the Potency of Delafloxacin and Ciprofloxacin against Urogenic Escherichia coli and Klebsiella pneumoniae.

PubMed

So, Wonhee; Crandon, Jared L; Nicolau, David P

2015-08-01

We assessed the effects of the urine matrix and its varying pH on the potency of the novel broad-spectrum fluoroquinolone delafloxacin and of ciprofloxacin against 16 urogenic Enterobacteriaceae in the urine of patients with suspected urinary tract infection. We determined minimum inhibitory concentrations in broth and urine using microdilution in 9 Escherichia coli and 7 Klebsiella pneumoniae specimens. The change in potency between broth and urine was calculated. Against 16 highly ciprofloxacin resistant Enterobacteriaceae with a broth minimum inhibitory concentration of 32 mg/l or greater the minimum inhibitory concentration in delafloxacin in broth was 2 mg/l (1 and 0 isolates of E. coli and K. pneumoniae, respectively), 4 mg/l (3 and 0), 8 mg/l (3 and 1), 16 mg/l (2 and 4) and 32 mg/l (0 and 2). Across the 143 collected urines pH ranged from 4.7 to 9.0 with 71% at pH 6.5 or less. The delafloxacin minimum inhibitory concentration measured in 80% urine from 100 unique patient samples (pH 5.0 to 8.3) was 2 mg/l or less (18% and 0.8% for E. coli and K. pneumoniae, respectively), 4 mg/l (23% and 6%), 8 mg/l (21% and 18%), 16 mg/l (23% and 33%) and 32 mg/l or greater (15% and 42%). For E. coli and K. pneumoniae combined the median changes in the delafloxacin minimum inhibitory concentration were a 1 doubling dilution decrease at pH 6.0 or less, no change at pH 6.1 to 7.0 and a 1 doubling dilution increase at pH 7.1 or greater. Unlike delafloxacin, ciprofloxacin showed a 1 doubling dilution increase for E. coli and no change for K. pneumoniae at pH 7.0 or less with no change observed at pH 7.1 or greater. Most urines collected from patients with urinary tract infection had a pH of 6.5 or less. Delafloxacin broth minimum inhibitory concentrations were twofold to fivefold doubling dilutions lower than those of ciprofloxacin. In contrast to ciprofloxacin, the potency of delafloxacin was further enhanced in the acidic environment commonly observed in the setting of urinary tract infection. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Antifungal susceptibility testing of Malassezia yeast: comparison of two different methodologies.

PubMed

Rojas, Florencia D; Córdoba, Susana B; de Los Ángeles Sosa, María; Zalazar, Laura C; Fernández, Mariana S; Cattana, María E; Alegre, Liliana R; Carrillo-Muñoz, Alfonso J; Giusiano, Gustavo E

2017-02-01

All Malassezia species are lipophilic; thus, modifications are required in susceptibility testing methods to ensure their growth. Antifungal susceptibility of Malassezia species using agar and broth dilution methods has been studied. Currently, few tests using disc diffusion methods are being performed. The aim was to evaluate the in vitro susceptibility of Malassezia yeast against antifungal agents using broth microdilution and disc diffusion methods, then to compare both methodologies. Fifty Malassezia isolates were studied. Microdilution method was performed as described in reference document and agar diffusion test was performed using antifungal tablets and discs. To support growth, culture media were supplemented. To correlate methods, linear regression analysis and categorical agreement was determined. The strongest linear association was observed for fluconazole and miconazole. The highest agreement between both methods was observed for itraconazole and voriconazole and the lowest for amphotericin B and fluconazole. Although modifications made to disc diffusion method allowed to obtain susceptibility data for Malassezia yeast, variables cannot be associated through a linear correlation model, indicating that inhibition zone values cannot predict MIC value. According to the results, disc diffusion assay may not represent an alternative to determine antifungal susceptibility of Malassezia yeast. © 2016 Blackwell Verlag GmbH.

Analysis of Fatty Acid and Growth Profiles in Ten Shewanella spp. to Associate Phylogenetic Relationships

DTIC Science & Technology

2015-10-25

in a defined medium composed of half-strength Marine Broth adjusted to pH 6, 7, or 8 in a 50 mM phosphate buffer, both growth characteristics and...work had broad phylogenetic diversity (Fig. 1) and were isolated from mostly marine environments. S. putrefaciens was the only strain that was not...the defined medium that supported growth of most of the strains tested was marine broth diluted to half strength with 50 mM phosphate buffer (½-MB

Antibiotic Fermentation Broth Treatment by a pilot upflow anaerobic sludge bed reactor and kinetic modeling.

PubMed

Coskun, T; Kabuk, H A; Varinca, K B; Debik, E; Durak, I; Kavurt, C

2012-10-01

In this study, an upflow anaerobic sludge blanket (UASB) mesophilic reactor was used to remove antibiotic fermentation broth wastewater. The hydraulic retention time was held constant at 13.3 days. The volumetric organic loading value increased from 0.33 to 7.43 kg(COD)m(-3)d(-1) using antibiotic fermentation broth wastewater gradually diluted with various ratios of domestic wastewater. A COD removal efficiency of 95.7% was obtained with a maximum yield of 3,700 L d(-1) methane gas production. The results of the study were interpreted using the modified Stover-Kincannon, first-order, substrate mass balance and Van der Meer and Heertjes kinetic models. The obtained kinetic coefficients showed that antibiotic fermentation broth wastewater can be successfully treated using a UASB reactor while taking COD removal and methane production into account. Copyright © 2012 Elsevier Ltd. All rights reserved.

Evaluation of in vitro properties of di-tri-octahedral smectite on clostridial toxins and growth.

PubMed

Weese, J S; Cote, N M; deGannes, R V G

2003-11-01

Clostridial colitis and endotoxaemia of intestinal origin are significant causes of morbidity and mortality in horses. Intestinal adsorbents are available for treatment of these conditions; however, little information exists supporting their use. To evaluate the ability of di-tri-octahedral smectite to bind to Clostridium difficile toxins A and B, C. perfringens enterotoxin and endotoxin, inhibit clostridial growth and the actions of metronidazole in vitro. Clostridium difficile toxins, C. perfringens enterotoxin and endotoxin were mixed with serial dilutions of di-tri-octahedral smectite, then tested for the presence of clostridial toxins or endotoxin using commercial tests. Serial dilutions of smectite were tested for the ability to inhibit growth of C. perfringens in culture broth, and to interfere with the effect of metronidazole on growth of C. perfringens in culture broth. Clostridium difficile toxins A and B, and C. perfringens enterotoxin were completely bound at dilutions of 1:2 to 1:16. Partial binding of C. difficile toxins occurred at dilutions up to 1:256 while partial binding of C. perfringens enterotoxin occurred up to a dilution of 1:128. Greater than 99% binding of endotoxin occurred with dilutions 1:2 to 1:32. No inhibition of growth of C. difficile or C. perfringens was present at any dilution, and there was no effect on the action of metronidazole. Di-tri-octahedral smectite possesses the ability to bind C. difficile toxins A and B, C. perfringens enterotoxin and endotoxin in vivo while having no effect on bacterial growth or the action of metronidazole. In vivo studies are required to determine whether di-tri-octahedral smectite might be a useful adjunctive treatment of clostridial colitis and endotoxaemia in horses.

Accuracy of the Thermo Fisher Scientific (Sensititre™) dry-form broth microdilution MIC product when testing ceftaroline.

PubMed

Jones, Ronald N; Holliday, Nicole M; Critchley, Ian A

2015-04-01

Ceftaroline, the active metabolite of the ceftaroline fosamil pro-drug, was the first advanced-spectrum cephalosporin with potent activity against methicillin-resistant Staphylococcus aureus to be approved by the US Food and Drug Administration for acute bacterial skin and skin structure infections. After 4 years of clinical use, few ceftaroline commercial susceptibility testing devices other than agar diffusion methods (disks and stable gradient) are available. Here, we validate a broth microdilution product (Sensititre™; Thermo Fisher Scientific, Cleveland, OH, USA) that achieved 99.2% essential agreement (manual and automated reading) and 95.3-100.0% categorical agreement, with high reproducibility (98.0-100.0%). Sensititre™ MIC values for ceftaroline, however, were slightly skewed toward an elevated value (0.5 × log2 dilution step), greatest when testing for streptococci and Enterobacteriaceae. Copyright © 2015 Elsevier Inc. All rights reserved.

A cryopreservation method for Pasteurella multocida from wetland samples

USGS Publications Warehouse

Moore, Melody K.; Shadduck, D.J.; Goldberg, Diana R.; Samuel, M.D.

1998-01-01

A cryopreservation method and improved isolation techniques for detection of Pasteurella multocida from wetland samples were developed. Wetland water samples were collected in the field, diluted in dimethyl sulfoxide (DMSO, final concentration 10%), and frozen at -180 C in a liquid nitrogen vapor shipper. Frozen samples were transported to the laboratory where they were subsequently thawed and processed in Pasteurella multocida selective broth (PMSB) to isolate P. multocida. This method allowed for consistent isolation of 2 to 18 organisms/ml from water seeded with known concentrations of P. multocida. The method compared favorably with the standard mouse inoculation method and allowed for preservation of the samples until they could be processed in the laboratory.

Antibiotic Susceptibility Evaluation of Group A Streptococcus Isolated from Children with Pharyngitis: A Study from Iran.

PubMed

Sayyahfar, Shirin; Fahimzad, Alireza; Naddaf, Amir; Tavassoli, Sara

2015-12-01

The aim of this study was to evaluate the antibiotic susceptibility of Group A streptococcus (GAS) to antibiotics usually used in Iran for treatment of GAS pharyngitis in children. From 2011 to 2013, children 3-15 years of age with acute tonsillopharyngitis who attended Mofid Children's Hospital clinics and emergency ward and did not meet the exclusion criteria were enrolled in a prospective study in a sequential manner. The isolates strains from throat culture were identified as GAS by colony morphology, gram staining, beta hemolysis on blood agar, sensitivity to bacitracin, a positive pyrrolidonyl aminopeptidase (PYR) test result, and the presence of Lancefield A antigen determined by agglutination test. Antimicrobial susceptibility was identified by both disk diffusion and broth dilution methods. From 200 children enrolled in this study, 59 (30%) cases were culture positive for GAS. All isolates were sensitive to penicillin G. The prevalence of erythromycin, azithromycin, and clarithromycin resistance by broth dilution method was 33.9%, 57.6%, and 33.9%, respectively. Surprisingly, 8.4% of GAS strains were resistant to rifampin. In this study, 13.5% and 32.2% of the strains were resistant to clindamycin and ofloxacin, respectively. The high rate of resistance of GAS to some antibiotics in this study should warn physicians, especially in Iran, to use antibiotics restrictedly and logically to prevent the rising of resistance rates in future. It also seems that continuous local surveillance is necessary to achieve the best therapeutic option for GAS treatment.

Antimicrobial susceptibility of Brachyspira hyodysenteriae isolated from 21 Polish farms.

PubMed

Zmudzki, J; Szczotka, A; Nowak, A; Strzelecka, H; Grzesiak, A; Pejsak, Z

2012-01-01

Swine dysentery (SD) is a common disease among pigs worldwide, which contributes to major production losses. Antimicrobial susceptibility testing of B. hyodysenteriae, the etiological agent of SD, is mainly performed by the agar dilution method. This method has certain limitations due to difficulties in interpretation of results. The aim of this study was the analysis of antimicrobial susceptibility of Brachyspira hyodysenteriae (B. hyodysenteriae) Polish field isolates by broth microdilution procedure. The study was performed on 21 isolates of B. hyodysenteriae, collected between January 2006 to December 2010 from cases of swine dysentery. VetMIC Brachyspira panels with antimicrobial agents (tiamulin, valnemulin, doxycycline, lincomycin, tylosin and ampicillin) were used for susceptibility testing of B. hyodysenteriae. The minimal inhibitory concentration (MIC) was determined by the broth dilution procedure. The lowest antimicrobial activity was demonstrated for tylosin and lincomycin, with inhibition of bacterial growth using concentrations > 128 microg/ml and 32 microg/ml, respectively. In the case of doxycycline, the MIC values were < or = 2.0 microg/ml. No decreased susceptibility to tiamulin was found among the Polish isolates and MIC values for this antibiotic did not exceed 1.0 microg/ml. The results of the present study confirmed that Polish B. hyodysenteriae isolates were susceptible to the main antibiotics (tiamulin and valnemulin) used in treatment of swine dysentery. Further studies are necessary to evaluate a possible slow decrease in susceptibility to tiamulin and valnemulin of B. hyodysenteriae strains in Poland.

Xanthan gum recovery from fermentation broth using ultrafiltration: Kinetics and process evaluation

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

Lo, Y.M.; Yang, S.T.; Min, D.B.

1995-12-01

Ultrafiltration of xanthan gum solution as an alternative method to alcohol precipitation for xanthan gum recovery from dilute fermentation broth was studied. A polysulfone membrane (with 500,000 MWCO) hollow fiber (106 mil fiber diameter) tubular cartridge was used to concentrate xanthan broth from less than 3 (w/v) % to {approximately}13.5 (w/v) %, with the xanthan recovery yield of {approximately}95 % or higher. During ultrafiltration, the filtrate flux was one order of magnitude lower for xanthan broth than for water, However, the flux remained almost constant for xanthan concentrations up to {approximately}8%. It was then reduced dramatically as the xanthan concentrationmore » increased beyond 8%. The reduced filtrate flux was caused by the reduced pumping (shear) rate and higher viscosities at higher xanthan concentrations. At constant xanthan concentration, the filtrate flux remained almost unchanged for the entire period studied, suggesting that the process is not subject to membrane fouling. In general, the filtrate flux decreased with increasing the xanthan concentration and increased with increasing the pumping (shear) rate and the trans-membrane pressure difference. Changing the solution pH had a slight effect on the viscosity of xanthan solution, but did not affect the filtration performance. Even under high-shear-rate conditions, ultrafiltration did not give any adverse effects on the rheological properties and molecular weight of the xanthan polymer. Thus, ultra filtration can be used to concentrate xanthan broth from fermentation by a factor of four or higher and to reduce the subsequent alcohol recovery costs by at least 75 %.« less

Semiautomated Method for Microbiological Vitamin Assays

PubMed Central

Berg, T. M.; Behagel, H. A.

1972-01-01

A semiautomated method for microbiological vitamin assays is described, which includes separate automated systems for the preparation of the cultures and for the measurement of turbidity. In the dilution and dosage unit based on the continuous-flow principle, vitamin samples were diluted to two different dose levels at a rate of 40 per hr, mixed with the inoculated test broth, and dispensed into culture tubes. After incubation, racks with culture tubes were placed on the sampler of an automatic turbidimeter. This unit, based on the discrete-sample system, measured the turbidity and printed the extinction values at a rate of 300 per hr. Calculations were computerized and the results, including statistical data, are presented in an easily readable form. The automated method is in routine use for the assays of thiamine, riboflavine, pyridoxine, cyanocobalamin, calcium pantothenate, nicotinic acid, pantothenol, and folic acid. Identical vitamin solutions assayed on different days gave variation coefficients for the various vitamin assays of less than 10%. Images PMID:4553802

Efficient ethanol recovery from fermentation broths with integrated distillation-membrane process

EPA Science Inventory

The energy demand of distillation-molecular sieve systems for ethanol recovery/dehydration can be significant, particularly for dilute solutions. An alternative process integrating vapor stripping (like a beer still) with vapor compression and a vapor permeation membrane separati...

Evaluation of Carbohydrate-Derived Fulvic Acid (CHD-FA) as a Topical Broad-Spectrum Antimicrobial for Drug-Resistant Wound Infections

DTIC Science & Technology

2013-10-01

0.5 0.5 Aspergillus flavus 12 0.5 0.5 0.5 0.5 Aspergillus terreus 5 0.125 0.125 0.5 0.5 Aspergillus niger 10 0.5 0.5 0.5 0.5 Candida albicans...Candida spp., Aspergillus fumigatus and polyene-resistant non-fumigatus Aspergillus species, Fusarium species and Zygomycetes. We have also established a... Aspergillus strains, and the CLSI protocol M27-A3 “Reference Method for Broth Dilution Antifungal Susceptibility Testing of Yeasts; Approved Standard- Third

Synergistic Effects of Honey and Propolis toward Drug Multi-Resistant Staphylococcus Aureus, Escherichia Coli and Candida Albicans Isolates in Single and Polymicrobial Cultures

PubMed Central

AL-Waili, Noori; Al-Ghamdi, Ahmad; Ansari, Mohammad Javed; Al-Attal, Y.; Salom, Khelod

2012-01-01

Background: Propolis and honey are natural bee products with wide range of biological and medicinal properties. The study investigated antimicrobial activity of ethyl alcohol extraction of propolis collected from Saudi Arabia (EEPS) and from Egypt (EEPE), and their synergistic effect when used with honey. Single and polymicrobial cultures of antibiotic resistant human pathogens were tested. Material and methods; Staphylococcus aureus (S. aureus),), Escherichia coli (E. coli) and Candida albicans (C.albicans) were cultured in 10-100% (v/v) honey diluted in broth, or 0.08-1.0% (weight/volume) EEPS and EEPE diluted in broth. Four types of polymicrobial cultures were prepared by culturing the isolates with each other in broth (control) and broth containing various concentrations of honey or propolis. Microbial growth was assessed on solid plate media after 24 h incubation. Results; EEPS and EEPE inhibited antibiotic resistant E.coli, and S.aureus, and C.albicans in single and polymicrobial cultures. S.aureus became more susceptible when it was cultured with E.coli or C.albicans or when all cultured together. C.albicans became more susceptible when it was cultured with S.aureus or with E.coli and S. aureus together. The presence of ethyl alcohol or honey potentiated antimicrobial effect of propolis toward entire microbes tested in single or polymicrobial cultures. EEPS had lower MIC toward E.coli and C.albicans than EEPE. When propolis was mixed with honey, EEPS showed lower MIC than EEPE. In addition, honey showed lower MIC toward entire microbes when mixed with EEPS than when it was mixed with EEPE. Conclusion; 1) propolis prevents the growth of the microorganisms in single and mixed microbial cultures, and has synergistic effect when used with honey or ethyl alcohol, 2) the antimicrobial property of propolis varies with geographical origin, and 3) this study will pave the way to isolate active ingredients from honey and propolis to be further tested individually or in combination against human resistant infections. PMID:23136543

Impact of pretreatment and downstream processing technologies on economics and energy in cellulosic ethanol production.

PubMed

Kumar, Deepak; Murthy, Ganti S

2011-09-05

While advantages of biofuel have been widely reported, studies also highlight the challenges in large scale production of biofuel. Cost of ethanol and process energy use in cellulosic ethanol plants are dependent on technologies used for conversion of feedstock. Process modeling can aid in identifying techno-economic bottlenecks in a production process. A comprehensive techno-economic analysis was performed for conversion of cellulosic feedstock to ethanol using some of the common pretreatment technologies: dilute acid, dilute alkali, hot water and steam explosion. Detailed process models incorporating feedstock handling, pretreatment, simultaneous saccharification and co-fermentation, ethanol recovery and downstream processing were developed using SuperPro Designer. Tall Fescue (Festuca arundinacea Schreb) was used as a model feedstock. Projected ethanol yields were 252.62, 255.80, 255.27 and 230.23 L/dry metric ton biomass for conversion process using dilute acid, dilute alkali, hot water and steam explosion pretreatment technologies respectively. Price of feedstock and cellulose enzymes were assumed as $50/metric ton and 0.517/kg broth (10% protein in broth, 600 FPU/g protein) respectively. Capital cost of ethanol plants processing 250,000 metric tons of feedstock/year was $1.92, $1.73, $1.72 and $1.70/L ethanol for process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Ethanol production cost of $0.83, $0.88, $0.81 and $0.85/L ethanol was estimated for production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Water use in the production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment was estimated 5.96, 6.07, 5.84 and 4.36 kg/L ethanol respectively. Ethanol price and energy use were highly dependent on process conditions used in the ethanol production plant. Potential for significant ethanol cost reductions exist in increasing pentose fermentation efficiency and reducing biomass and enzyme costs. The results demonstrated the importance of addressing the tradeoffs in capital costs, pretreatment and downstream processing technologies.

Impact of pretreatment and downstream processing technologies on economics and energy in cellulosic ethanol production

PubMed Central

2011-01-01

Background While advantages of biofuel have been widely reported, studies also highlight the challenges in large scale production of biofuel. Cost of ethanol and process energy use in cellulosic ethanol plants are dependent on technologies used for conversion of feedstock. Process modeling can aid in identifying techno-economic bottlenecks in a production process. A comprehensive techno-economic analysis was performed for conversion of cellulosic feedstock to ethanol using some of the common pretreatment technologies: dilute acid, dilute alkali, hot water and steam explosion. Detailed process models incorporating feedstock handling, pretreatment, simultaneous saccharification and co-fermentation, ethanol recovery and downstream processing were developed using SuperPro Designer. Tall Fescue (Festuca arundinacea Schreb) was used as a model feedstock. Results Projected ethanol yields were 252.62, 255.80, 255.27 and 230.23 L/dry metric ton biomass for conversion process using dilute acid, dilute alkali, hot water and steam explosion pretreatment technologies respectively. Price of feedstock and cellulose enzymes were assumed as $50/metric ton and 0.517/kg broth (10% protein in broth, 600 FPU/g protein) respectively. Capital cost of ethanol plants processing 250,000 metric tons of feedstock/year was $1.92, $1.73, $1.72 and $1.70/L ethanol for process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Ethanol production cost of $0.83, $0.88, $0.81 and $0.85/L ethanol was estimated for production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Water use in the production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment was estimated 5.96, 6.07, 5.84 and 4.36 kg/L ethanol respectively. Conclusions Ethanol price and energy use were highly dependent on process conditions used in the ethanol production plant. Potential for significant ethanol cost reductions exist in increasing pentose fermentation efficiency and reducing biomass and enzyme costs. The results demonstrated the importance of addressing the tradeoffs in capital costs, pretreatment and downstream processing technologies. PMID:21892958

Short communication: Lactose enhances bile tolerance of yogurt culture bacteria.

PubMed

Mena, Behannis; Aryana, Kayanush

2018-03-01

Lactose is an energy source for culture bacteria. Bile tolerance is an important probiotic property. Our aim was to elucidate the effect of lactose on bile tolerance of yogurt starter culture Lactobacillus bulgaricus LB-12 and Streptococcus thermophilus ST-M5. Bile tolerance of pure cultures was determined using 0.3% oxgall in MRS THIO broth (Difco, Becton Dickinson, Sparks, MD) for L. bulgaricus and 0.3% oxgall in M17 broth (Oxoid, Basingstoke, UK) for Strep. thermophilus. Lactose was added to both broths at 0 (control), 1, 3, and 5% (wt/vol) broth. Dilutions were plated hourly for 12 h. Experiments were replicated 3 times. At 2, 4, and 12 h of incubation, lactose incorporated at all amounts, 1, 3, and 5% (wt/vol), showed higher counts of Strep. thermophilus ST-M5 compared with the control. Lactose use at 5% (wt/vol) significantly enhanced bile tolerance of both L. bulgaricus and Strep. thermophilus compared with control. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Pervaporation & Vapor Permeation Membrane Processes for the Selective Separation of Liquid and Vapor Mixtures

EPA Science Inventory

Pervaporation and vapor permeation are membrane-based processes which have been proposed as alternatives to conventional separation technologies. Applications range from organic solvent removal from water, ethanol or butanol recovery from dilute fermentation broths, solvent/biofu...

Antimicrobial Efficacy of Octenidine Hydrochloride and Calcium Hydroxide with and Without a Carrier: A Broth Dilution Analysis

PubMed Central

Varghese, Vinaya Susan; Uppin, Veerendra; Bhat, Kishore; Pujar, Madhu; Hooli, Amruta B.; Kurian, Nirmal

2018-01-01

Background: An efficient antimicrobial agent action is required for a predetermined time period for absolute elimination of root canal microbes. Till date, there is limited or no data on the antimicrobial effect of octenidine as an intracanal medicament with chitosan (CTS) as a carrier against Candida albicans and Enterococcus faecalis. Aim: The aim of this microbiological study was to compare the antimicrobial efficacy of octenidine hydrochloride (OHC) and calcium hydroxide (Ca[OH]2) as intracanal medicaments, both independently and along with CTS as a carrier molecule against the common resistant endodontic pathogens. Materials and Methods: A total of 160 single-rooted anterior teeth were selected, root canal preparation was done, and teeth were divided into two groups and contaminated with C. albicans and E. faecalis, which were further divided into four test groups each according to intracanal medicaments used. CTS was used as a vehicle for OHC and Ca(OH)2 and antimicrobial assessment was performed on day 2 and day 7 following broth dilution method. Dentine samples were collected after each time interval, and the number of colony-forming units was determined. Results: All four medicaments used in this study showed antifungal and antibacterial activity that diminished from day 2 to day 7. Group I (OHC alone) and Group IV (Ca[OH]2 alone) showed significant antimicrobial activity against C. albicans and E. faecalis, respectively, than the other groups. Conclusion: A combination of OHC + CTS and Ca(OH)2+ CTS produced inferior results than that of the medicaments used alone. PMID:29599588

Efficient ethanol recovery from fermentation broths with integrated distillation-vapor permeation hybrid process

EPA Science Inventory

The energy demand of distillation-molecular sieve systems for ethanol recovery/dehydration can be significant, particularly for dilute solutions. An alternative hybrid process integrating vapor stripping (like a beer still) with vapor compression and a vapor permeation membrane s...

Antifungal activity of Morinda citrifolia fruit extract against Candida albicans.

PubMed

Jainkittivong, Aree; Butsarakamruha, Tassanee; Langlais, Robert P

2009-09-01

The objective of the study was to investigate the antifungal activity of Morinda citrifolia fruit extract on Candida albicans. Juice extract from M. citrifolia fruit was lyophilized and used in antifungal testing. Antifungal activity of M. citrifolia fruit extract against C. albicans was tested in vitro at various concentrations and for different contact times. The inhibitory effect of M. citrifolia extract on C. albicans was determined by cultures and an applied broth dilution test. Using cultures, growth of C. albicans was not detected with 50 mg/mL of extract at 30-minute contact time or with 60 mg/mL of extract at 15-minute contact time. By the broth dilution test, the minimum fungicidal concentration of extract against C. albicans was 40 mg/mL at 90-minute contact time or with 50 mg/mL at 15-minute contact time. M. citrifolia fruit extract had an antifungal effect on C. albicans and the inhibitory effect varied with concentration and contact time.

Effects of natural honey on polymicrobial culture of various human pathogens

PubMed Central

Al-Waili, Faiza S.; Akmal, Mohammed; Ali, Amjed; Salom, Khelod Y.; Al Ghamdi, Ahmad A.

2012-01-01

Introduction Honey has a wide range of antimicrobial activity. All previous studies have considered honey's effect on a single microbe. The present study investigated activity of honey towards a high dose of single or polymicrobial culture. Material and methods 10 µl specimens of Staphylococcus aureus (S. aureus), Streptococcus pyogenes (S. pyogenes), Escherichia coli (E. coli) and Candida albicans (C. albicans) were cultured in 10 ml of 10-100% (wt/v) honey diluted in broth. Six types of polymicrobial microbial cultures were prepared by culturing the isolates with each other onto broth (control) and broth containing various concentrations of honey (10-100% wt/v). Microbial growth was assessed on solid plate media after 24 h incubation. Results Honey (30-70%) prevents growth of 10 µl specimens of all the isolates. Greater reduction in growth of E. coli was observed when cultured with S. aureus. Culturing of S. aureus with S. pyogenes, C. albicans, or E. coli increased its sensitivity to honey. S. aureus and S. pyogenes increased sensitivity of C. albicans to honey while E. coli and C. albicans decreased sensitivity of S. pyogenes. Conclusions It might be concluded that honey prevents and inhibits growth of single and polymicrobial pathogenic cultures. Polymicrobial culture affects growth of the isolates and increases their sensitivity to honey. PMID:24904656

Magnetic nanoparticle-enhanced PCR for the detection and identification of Staphylococcus aureus and Salmonella enteritidis.

PubMed

Houhoula, Dimitra; Papaparaskevas, Joseph; Zatsou, Katerina; Nikolaras, Nikolaos; Malkawi, Hanan I; Mingenot-Leclercq, Marie-Paule; Konteles, Spyros; Koussisis, Stamatis; Tsakris, Athanassios; Charvalos, Ekatherina

2017-07-01

This paper evaluated magnetic nanoparticle-enhanced PCR for the detection and identification of Staphylococcus aureus and Salmonella enteritidis. Two different types of magnetic nanoparticles designated MPIO (iron concentration 2.5 mg/ml, size 1 µm) and NP (iron concentration 8.7 mg/ml, size 60 nm), both conjugated with S. aureus or S. enteritidis antibodies were evaluated as an enrichment procedure for PCR-detection of the pathogens in Trypticase Soy Broth, milk, blood and meat broth. Bacterial suspensions (1.5x108 cfu/ml) were prepared and serial diluted 10-1. The MPIO and NP nanoparticles were added, followed by incubation for 1 hour at room temperature, magnetic separation of the pellet, DNA extraction and PCR, targeting the femA and invA sequences. The nanoparticle-free and the NP-supplemented dilutions were positive down to the 1.5x102 cfu/ml concentration for both bacteria. The MPIO-supplemented dilutions were positive down to approx. 2x100 cfu/ml concentration, respectively. Bacteria-free TSB was negative by PCR. MPIO nanoparticles (size 1 µm) enhanced the detection of S. aureus and S. enteritidis by PCR, whilst NP nanoparticles (size 60 nm) did not, thus indicating that the size of the magnetic nanoparticles play a significant role in the enrichment procedure.

Antimicrobial activity and chemical analysis of Microlicia hatschbachii Wurdack (Melastomataceae) extract.

PubMed

Cassiano, Dayse S A; Pacheco, Alessandra G M; da Costa, Mateus M; Almeida, Jackson R G S; Vieira, Ivo J C; Branco, Alexsandro

2014-01-01

Aerial parts of Microlicia hatschbachii were extracted with hexane, and the extract was evaluated for antimicrobial activity by a broth dilution method. After phytochemical procedures: GC-MS identified aliphatic alkanes, carboxylic acids and methyl esters of long-chain fatty acids; and two diterpenoids [labd-8(17)-en-15-oic acid and labd-8(17),13-dien-15-oic acid] were identified by (1)H and (13)C NMR. The antimicrobial activity of the hexane extract could be attributed to the presence of labdanes. This identification is the first reported occurrence of labdane diterpenes in the Melastomataceae family.

Pilot microscreen separation of Sclerotium rolfsii biomass and broth. [Sclerotium rolfsii

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

Griffith, W.L.; Compere, A.L.; Cravens, J.B.

1981-01-01

Field production of scleroglucan biopolymer for micellular flooding near an injection well could eliminate two major polymer production costs, alcohol precipitation of polymer broth and resuspension of dry polymer in water. The use of microscreening could decrease these and another major polymer production cost, that of diatomaceous earth filtration. Bench and pilot tests using Rexnord 1, 6, and 21-..mu..m screens indicate that they provide efficient removal of gross solids from Sclerotium rolfsii culture broth partially diluted to viscosities suitable for field injection. Pilot centrifuge tests indicate that the microscreen backwash could be concentrated to a solid content of 2 tomore » 3% as volatile suspended solids, suitable for animal feed or by-product use. Although polishing filtration is required to remove residual formation plugging constituents, substantial decreases in capital costs and operating energy appear attainable if microscreening is used. 3 figures, 3 tables.« less

Benzeneboronic acid selectively inhibits sporulation of Bacillis subtilis.

PubMed Central

Davis-Mancini, K; Lopez, I P; Hageman, J H

1978-01-01

m-Aminobenzeneboronic acid at levels of 0.2 mM in nutrient broth medium selectively inhibited sporulation without appreciably altering vegetative growth. Significant inhibitory effects were seen even when it was added as late as 6 h after the end of logarithmic growth. The pH changes associated with growth and sporulation of Bacillus subtilis in nutrient broth were not significantly altered by the inhibitor. When it was present in cultures of actively growing cells, its inhibitory effect could not be reversed by simple dilution. The compound caused extensive clumping, of cells, which appeared not to be related to the ability of boronates to esterify to diols. Images PMID:30755

Valorization of Spent Escherichia coli Media Using Green Microalgae Chlamydomonas reinhardtii and Feedstock Production

PubMed Central

Zhang, Jian-Guo; Zhang, Fang; Thakur, Kiran; Hu, Fei; Wei, Zhao-Jun

2017-01-01

The coupling of Chlamydomonas reinhardtii biomass production for nutrients removal of Escherichia coli anaerobic broth (EAB) is thought to be an economically feasible option for the cultivation of microalgae. The feasibility of growing microalgae in using EAB high in nutrients for the production of more biomass was examined. EAB comprised of nutrient-abundant effluents, which can be used to produce microalgae biomass and remove environment pollutant simultaneously. In this study, C. reinhardtii 21gr (cc1690) was cultivated in different diluted E. coli anaerobic broth supplemented with trace elements under mixotrophic and heterotrophic conditions. The results showed that C. reinhardtii grown in 1×, 1/2×, 1/5× and 1/10×E. coli anaerobic broth under mixotrophic conditions exhibited specific growth rates of 2.71, 2.68, 1.45, and 1.13 day-1, and biomass production of 201.9, 184.2, 175.5, and 163.8 mg L-1, respectively. Under heterotrophic conditions, the specific growth rates were 1.80, 1.86, 1.75, and 1.02 day-1, and biomass production were 45.6, 29.4, 15.8, and 12.1 mg L-1, respectively. The removal efficiency of chemical oxygen demand, total-nitrogen and total-phosphorus from 1×E. coli anaerobic broth was 21.51, 22.41, and 15.53%. Moreover, the dry biomass had relatively high carbohydrate (44.3%) and lipid content (18.7%). Therefore, this study provides an environmentally sustainable as well economical method for biomass production in promising model microalgae and subsequently paves the way for industrial use. PMID:28638375

First Comprehensive Evaluation of the M.I.C. Evaluator Device Compared to Etest and CLSI Broth Microdilution for MIC Testing of Aerobic Gram-Positive and Gram-Negative Bacterial Species

PubMed Central

Turnbull, L.; Brosnikoff, C.; Cloke, J.

2012-01-01

The M.I.C. Evaluator strip (Thermo Fisher Scientific, Basingstoke, United Kingdom) uses a methodology similar to that of Etest. In this first assessment of the M.I.C. Evaluator device, 409 strains of aerobic Gram-positive bacteria (staphylococci, streptococci, and enterococci) and 325 strains of Enterobacteriaceae, Pseudomonas species, and Acinetobacter species were tested by M.I.C. Evaluator strip, Etest, and broth microdilution as a reference standard. The Gram-positive bacteria included staphylococci (methicillin-resistant Staphylococcus aureus, methicillin-susceptible S. aureus, and coagulase-negative staphylococci), Streptococcus pneumoniae, beta-hemolytic streptococci and viridians group strains, vancomycin-resistant enterococci, and other enterococci. The Gram-negative bacteria included 250 strains of 60 Enterobacteriaceae species plus 50 Pseudomonas and 25 Acinetobacter species. A total of 14 antimicrobial agents (depending on the species) were included. The same methodology and reading format were used for M.I.C. Evaluator strips and Etest. Broth microdilution methodology was performed according to CLSI document M07-A8. For the clinical strains, >95% of results were plus or minus one doubling dilution for all species. There were fewer than 5% minor errors, fewer than 3% major errors, and fewer than 1% very major errors. M.I.C. Evaluator strips and Etest often reported higher MICs than the reference broth microdilution method. The M.I.C. Evaluator strips provided results comparable to those of the predicate Etest device and are of value for the accurate testing of MICs for these important pathogens. PMID:22238441

Antimicrobial Efficacy of Octenidine Hydrochloride and Calcium Hydroxide with and Without a Carrier: A Broth Dilution Analysis.

PubMed

Varghese, Vinaya Susan; Uppin, Veerendra; Bhat, Kishore; Pujar, Madhu; Hooli, Amruta B; Kurian, Nirmal

2018-01-01

An efficient antimicrobial agent action is required for a predetermined time period for absolute elimination of root canal microbes. Till date, there is limited or no data on the antimicrobial effect of octenidine as an intracanal medicament with chitosan (CTS) as a carrier against Candida albicans and Enterococcus faecalis . The aim of this microbiological study was to compare the antimicrobial efficacy of octenidine hydrochloride (OHC) and calcium hydroxide (Ca[OH] 2 ) as intracanal medicaments, both independently and along with CTS as a carrier molecule against the common resistant endodontic pathogens. A total of 160 single-rooted anterior teeth were selected, root canal preparation was done, and teeth were divided into two groups and contaminated with C. albicans and E. faecalis , which were further divided into four test groups each according to intracanal medicaments used. CTS was used as a vehicle for OHC and Ca(OH) 2 and antimicrobial assessment was performed on day 2 and day 7 following broth dilution method. Dentine samples were collected after each time interval, and the number of colony-forming units was determined. All four medicaments used in this study showed antifungal and antibacterial activity that diminished from day 2 to day 7. Group I (OHC alone) and Group IV (Ca[OH] 2 alone) showed significant antimicrobial activity against C. albicans and E. faecalis , respectively, than the other groups. A combination of OHC + CTS and Ca(OH) 2 + CTS produced inferior results than that of the medicaments used alone.

Effect of sample preparation and preenrichment media on the recovery of Salmonella from cantaloupes, mangoes, and tomatoes.

PubMed

Hammack, Thomas S; Johnson, Mildred L; Jacobson, Andrew P; Andrews, Wallace H

2006-01-01

Studies were conducted to determine the relative effectiveness of buffered peptone water (BPW), lactose (LAC) broth, and Universal Preenrichment (UP) broth for the recovery of Salmonella organisms from fruit rinses, whole fruit, and comminuted fruit. In the first phase, the relative effectiveness of the rinse and soak methods for the recovery of Salmonella from surface-contaminated mangoes and tomatoes was examined. Fruits were spot inoculated with single Salmonella serovars and held for 4 days at 2-6 degrees C before analysis was initiated. The contaminated fruit was rinsed in portions of BPW, LAC broth, or UP broth. Portions from each rinse were added to its respective broth (e.g., BPW to BPW). Individual whole fruit, in their remaining broth rinses (soak method), and the fruit rinse/broths (rinse method) were incubated for 24 h at 35 degrees C. The Bacteriological Analytical Manual (BAM) Salmonella culture method was followed thereafter. The soak method produced significantly greater numbers (P < 0.05) of positive test portions than did the rinse method for the analysis of mangoes (93 versus 12) and tomatoes (85 versus 34). The 3 broths were comparable for the recovery of Salmonella for both the soak and the rinse methods for mangoes. For tomatoes, there were no significant differences among the broths for the soak method, but BPW and UP broth were significantly more productive (P < 0.05) than LAC broth by the rinse method. In the second phase, the relative effectiveness of LAC broth, BPW, and UP broth for the recovery of Salmonella from comminuted fruit was examined. Fruits were contaminated with single Salmonella serovars and aged for 4 days at 2-6 degrees C. Twenty 25 g test portions were preenriched in each of the following broths: BPW, LAC broth, and UP broth. The BAM Salmonella culture method was followed thereafter. For cantaloupes, significantly more (P < 0.05) Salmonella-positive test portions were recovered with UP broth (96 Salmonella-positive test portions) and BPW (87 Salmonella-positive test portions) than with LAC broth (57 Salmonella-positive test portions). For mangoes, BPW recovered an arithmetically larger number of Salmonella-positive test portions (27 Salmonella-positive test portions) than did either LAC broth (14 Salmonella-positive test portions) or UP broth (18 Salmonella-positive test portions). For tomatoes, there were no significant differences among the broths: BPW recovered 65 Salmonella-positive test portions, UP broth recovered 62 Salmonella-positive test portions, and LAC broth recovered 60 Salmonella-positive test portions. For the analysis of whole fruit, it is recommended that the soak method be used. For whole fruit analyzed with the soak method, UP broth should be used for tomatoes and BPW should be used for mangoes. It is further recommended that UP broth be used for the analysis of comminuted cantaloupes and that BPW be used for the analysis of comminuted mangoes and tomatoes.

Self-assembling systems based on quaternized derivatives of 1,4-diazabicyclo[2.2.2]octane in nutrient broth as antimicrobial agents and carriers for hydrophobic drugs.

PubMed

Pashirova, Tatiana N; Lukashenko, Svetlana S; Zakharov, Sergey V; Voloshina, Alexandra D; Zhiltsova, Elena P; Zobov, Vladimir V; Souto, Eliana B; Zakharova, Lucia Ya

2015-03-01

Aggregation properties of mono (mono-CS) and dicationic (di-CS) surfactants, namely quaternised derivatives of 1,4-diazabicyclo[2.2.2]octane (DABCO), have been evaluated in water and in nutrient broths of different pH, i.e. in Hottinger broth (рН=7.2) and Sabouraud dextrose broth (рН=5.6). Aggregation capacity of surfactants was shown to be responsible for the solubilization properties of a complex composed of a hydrophobic probe (Sudan I) and a selected drug (quercetin), contributing to the antimicrobial activity of this surfactant system. The effect of N-methyl-d-glucamine (NmDg) additive on the antimicrobial activity of mono-CS, and its aggregation and solubilization parameters, has also been evaluated. A substantial decrease in critical micelle concentration (CMC) of cationic surfactants in nutrient broths (up to 60 times) has been reported. Twofold dilution of monocationic surfactant by NmDg slightly changed the CMC of surfactant; however, it provided a remarkable increase in solubilization capacity (∼by 4 times) and decrease in its toxicity. The data anticipate the potential use of DABCO quaternized derivatives as innovative non-toxic delivery systems for hydrophobic drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

Antifungal mechanisms supporting boric acid therapy of Candida vaginitis.

PubMed

De Seta, Francesco; Schmidt, Martin; Vu, Bao; Essmann, Michael; Larsen, Bryan

2009-02-01

Boric acid is a commonly cited treatment for recurrent and resistant yeast vaginitis, but data about the extent and mechanism of its antifungal activity are lacking. The aim of this study was to use in vitro methods to understand the spectrum and mechanism of boric acid as a potential treatment for vaginal infection. Yeast and bacterial isolates were tested by agar dilution to determine the intrinsic antimicrobial activity of boric acid. Established microbial physiology methods illuminated the mechanism of the action of boric acid against Candida albicans. C. albicans strains (including fluconazole-resistant strains) were inhibited at concentrations attainable intravaginally; as were bacteria. Broth dilution MICs were between 1563 and 6250 mg/L and boric acid proved fungistatic (also reflected by a decrease in CO(2) generation); prolonged culture at 50,000 mg/L was fungicidal. Several organic acids in yeast nitrogen broth yielded a lower pH than equimolar boric acid and sodium borate but were less inhibitory. Cold or anaerobic incubation protected yeast at high boric acid concentrations. Cells maintained integrity for 6 h in boric acid at 37 degrees C, but after 24 h modest intrusion of propidium iodide occurred; loss of plate count viability preceded uptake of vital stain. Growth at sub-MIC concentrations of boric acid decreased cellular ergosterol. The drug efflux pump CDR1 did not protect Candida as CDR1 expression was abrogated by boric acid. Boric acid interfered with the development of biofilm and hyphal transformation. Boric acid is fungistatic to fungicidal depending on concentration and temperature. Inhibition of oxidative metabolism appears to be a key antifungal mechanism, but inhibition of virulence probably contributes to therapeutic efficacy in vivo.

Detection of Phytophthora ramorum chlamydospores in soil by baiting and dilution plating

USDA-ARS?s Scientific Manuscript database

Chlamydospores of P. ramorum produced by mixing 20 percent V8 juice broth cultures with sand and incubating over a 1 month period were used to infest field soil at concentrations ranging from 0.2 to 42 chlamydospores/cc soil. Chlamydospore recovery was determined by baiting with rhododendron leaf d...

Multisite reproducibility of the broth microdilution method for susceptibility testing of Nocardia species.

PubMed

Conville, Patricia S; Brown-Elliott, Barbara A; Wallace, Richard J; Witebsky, Frank G; Koziol, Deloris; Hall, Geraldine S; Killian, Scott B; Knapp, Cindy C; Warshauer, David; Van, Tam; Wengenack, Nancy L; Deml, Sharon; Woods, Gail L

2012-04-01

Antimicrobial susceptibility testing (AST) of clinical isolates of Nocardia is recommended to detect resistance to commonly used antimicrobial agents; such testing is complicated by difficulties in inoculum preparation and test interpretation. In this study, six laboratories performed repetitive broth microdilution testing on single strains of Nocardia brasiliensis, Nocardia cyriacigeorgica, Nocardia farcinica, Nocardia nova, and Nocardia wallacei. For each isolate, a total of 30 microdilution panels from three different lots were tested at most sites. The goal of the study was to determine the inter- and intralaboratory reproducibility of susceptibility testing of this group of isolates. Acceptable agreement (>90% agreement at ±1 dilution of the MIC mode) was found for amikacin, ciprofloxacin, clarithromycin, and moxifloxacin. After eliminating MIC values from single laboratories whose results showed the greatest deviation from those of the remaining laboratories, acceptable agreement was also found for amoxicillin-clavulanic acid, linezolid, minocycline, and tobramycin. Results showed unsatisfactory reproducibility of broth microdilution testing of ceftriaxone with N. cyriacigeorgica and N. wallacei, tigecycline with N. brasiliensis and N. cyriacigeorgica, and sulfonamides with N. farcinica and N. wallacei. N. nova ATCC BAA-2227 is proposed as a quality control organism for AST of Nocardia sp., and the use of a disk diffusion test for sulfisoxazole is proposed as a check of the adequacy of the inoculum and to confirm sulfonamide MIC results.

[In vitro activity of doripenem against strains from pediatric diseases and strains causing purulent meningitis].

PubMed

Ohta, Merime; Toba, Shinsuke; Ito, Akinobu; Nakamura, Rio; Tsuji, Masakatsu

2012-12-01

This study evaluated the in vitro activity of doripenem (DRPM) against 200 Streptococcus pneumoniae and 197 Haemophilus influenzae from children and adults in 2007, 50 H. influenzae type b in 2006, 20 Listeria monocytogenes in 1990-2005, 23 Neisseria meningitidis in 2007-2009 and 83 Bordetella pertussis in 1989-2003. All strains were isolated from Japanese clinical facilities. We also investigated in vitro activity of other carbapenems (meropenem, imipenem, panipenem, biapenem), cephems (ceftriaxone, cefotaxime), ampicillin and clarithromycin. The all MICs were determined by a broth micro dilution method or an agar dilution method according to CLSI. The MIC90(s) of DRPM against S. pneumoniae and H. influenzae from children were 0.25 microg/mL, 1 microg/mL, respectively, which were similar to strains from adults. These results suggested that antibacterial activity of DRPM is not variable by patient's age. DRPM also showed excellent activities against H. influenzae type b, L. monocytogenes and N. meningitidis, which cause purulent meningitis, and B. pertussis causing whooping cough more than the other carbapenems. DRPM showed superior activities against serious strains of pediatric infection diseases.

Determination of glucose and ethanol after enzymatic hydrolysis and fermentation of biomass using Raman spectroscopy.

PubMed

Shih, Chien-Ju; Smith, Emily A

2009-10-27

Raman spectroscopy has been used for the quantitative determination of the conversion efficiency at each step in the production of ethanol from biomass. The method requires little sample preparation; therefore, it is suitable for screening large numbers of biomass samples and reaction conditions in a complex sample matrix. Dilute acid or ammonia-pretreated corn stover was used as a model biomass for these studies. Ammonia pretreatment was suitable for subsequent measurements with Raman spectroscopy, but dilute acid-pretreated corn stover generated a large background signal that surpassed the Raman signal. The background signal is attributed to lignin, which remains in the plant tissue after dilute acid pretreatment. A commercial enzyme mixture was used for the enzymatic hydrolysis of corn stover, and glucose levels were measured with a dispersive 785 nm Raman spectrometer. The glucose detection limit in hydrolysis liquor by Raman spectroscopy was 8 g L(-1). The mean hydrolysis efficiency for three replicate measurements obtained with Raman spectroscopy (86+/-4%) was compared to the result obtained using an enzymatic reaction with UV-vis spectrophotometry detection (78+/-8%). The results indicate good accuracy, as determined using a Student's t-test, and better precision for the Raman spectroscopy measurement relative to the enzymatic detection assay. The detection of glucose in hydrolysis broth by Raman spectroscopy showed no spectral interference, provided the sample was filtered to remove insoluble cellulose prior to analysis. The hydrolysate was further subjected to fermentation to yield ethanol. The detection limit for ethanol in fermentation broth by Raman spectroscopy was found to be 6 g L(-1). Comparison of the fermentation efficiencies measured by Raman spectroscopy (80+/-10%) and gas chromatography-mass spectrometry (87+/-9%) were statistically the same. The work demonstrates the utility of Raman spectroscopy for screening the entire conversion process to generate lignocellulosic ethanol.

The visual assessment of broth cultures for tissue bank samples.

PubMed

Varettas, Kerry

2017-09-01

The bioburden screening process of allograft musculoskeletal tissue samples received at the South Eastern Area Laboratory Services includes the routine use of solid agar and cooked meat (CM) broth media. CM has been routinely sub-cultured onto solid agar plates after aerobic incubation at 35 °C. This study will evaluate whether a visual assessment of CM can replace sub-culture by an in vitro inoculation and a prospective study. Eight challenge organisms were serially diluted and inoculated into CM. The average inoculum of 0.5-5.5 CFU produced visible turbidity of CM after 24-h incubation for 7 of the challenge organisms with one organism producing turbidity after 48-h incubation. The prospective study evaluated 222 CM of which 213 were visually clear and no-growth on sub-culture and 9 turbid CM which were culture positive. Broth cultures are an integral part of the bioburden screening process of allograft musculoskeletal tissue and swab samples and visual assessment of CM can replace sub-culture.

Butanol production from wood pulping hydrolysate in an integrated fermentation-gas stripping process

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

Lu, CC; Dong, J; Yang, ST

2013-09-01

Wood pulping hydrolysate (WPH) containing mainly xylose and glucose as a potential substrate for acetone-butanol-ethanol (ABE) fermentation was studied. Due to the inhibitors present in the hydrolysate, several dilution levels and detoxification treatments, including overliming, activated charcoal adsorption, and resin adsorption, were evaluated for their effectiveness in relieving the inhibition on fermentation. Detoxification using resin and evaporation was found to be the most effective method in reducing the toxicity of WPH. ABE production in batch fermentation by Clostridium beijerinckii increased 68%, from 6.73 g/L in the non-treated and non-diluted WPH to 11.35 g/L in the resin treated WPH. With gasmore » stripping for in situ product removal, ABE production from WPH increased to 17.73 g/L, demonstrating that gas stripping was effective in alleviating butanol toxicity by selectively separating butanol from the fermentation broth, which greatly improved solvents production and sugar conversion in the fermentation. (C) 2013 Elsevier Ltd. All rights reserved.« less

Butanol production from wood pulping hydrolysate in an integrated fermentation-gas stripping process.

PubMed

Lu, Congcong; Dong, Jie; Yang, Shang-Tian

2013-09-01

Wood pulping hydrolysate (WPH) containing mainly xylose and glucose as a potential substrate for acetone-butanol-ethanol (ABE) fermentation was studied. Due to the inhibitors present in the hydrolysate, several dilution levels and detoxification treatments, including overliming, activated charcoal adsorption, and resin adsorption, were evaluated for their effectiveness in relieving the inhibition on fermentation. Detoxification using resin and evaporation was found to be the most effective method in reducing the toxicity of WPH. ABE production in batch fermentation by Clostridium beijerinckii increased 68%, from 6.73 g/L in the non-treated and non-diluted WPH to 11.35 g/L in the resin treated WPH. With gas stripping for in situ product removal, ABE production from WPH increased to 17.73 g/L, demonstrating that gas stripping was effective in alleviating butanol toxicity by selectively separating butanol from the fermentation broth, which greatly improved solvents production and sugar conversion in the fermentation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Anti-Helicobacter pylori activity of plants used in Mexican traditional medicine for gastrointestinal disorders.

PubMed

Castillo-Juárez, Israel; González, Violeta; Jaime-Aguilar, Héctor; Martínez, Gisela; Linares, Edelmira; Bye, Robert; Romero, Irma

2009-03-18

Helicobacter pylori is the major etiological agent of chronic active gastritis and peptic ulcer disease and is linked to gastric carcinoma. Treatment to eradicate the bacteria failed in many cases, mainly due to antibiotic resistance, hence the necessity of developing better therapeutic regimens. Mexico has an enormous unexplored potential of medicinal plants. This work evaluates the in vitro anti-H. pylori activity of 53 plants used in Mexican traditional medicine for gastrointestinal disorders. To test the in vitro antibacterial activity, agar dilution and broth dilution methods were used for aqueous and methanolic extracts, respectively. Aqueous extracts of Artemisia ludoviciana subsp. mexicana, Cuphea aequipetala, Ludwigia repens,and Mentha x piperita (MIC 125 to <250 microg/ml) as well as methanolic extracts of Persea americana, Annona cherimola, Guaiacum coulteri, and Moussonia deppeana (MIC <7.5 to 15.6 microg/ml) showed the highest inhibitory effect. The results contribute to understanding the mode of action of the studied medicinal plants and for detecting plants with high anti-Helicobacter pylori activity.

What is the true in vitro potency of oxytetracycline for the pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida?

PubMed

Dorey, L; Hobson, S; Lees, P

2017-10-01

The pharmacodynamics of oxytetracycline was determined for pig respiratory tract pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Indices of potency were determined for the following: (i) two matrices, broth and pig serum; (ii) five overlapping sets of twofold dilutions; and (iii) a high strength starting culture. For A. pleuropneumoniae, minimum inhibitory concentration (MIC) was similar for the two matrices, but for P. multocida, differences were marked and significantly different. MIC and minimum bactericidal concentration (MBC) serum: broth ratios for A. pleuropneumoniae were 0.83:1 and 1.22:1, respectively, and corresponding values for P. multocida were 22.0:1 and 7.34:1. For mutant prevention concentration (MPC) serum: broth ratios were 0.79:1 (A. pleuropneumoniae) and 20.9:1 (P. multocida). These ratios were corrected for serum protein binding to yield fraction unbound (fu) serum: broth MIC ratios of 0.24:1 (A. pleuropneumoniae) and 6.30:1 (P. multocida). Corresponding fu serum: broth ratios for MPC were almost identical, 0.23:1 and 6.08:1. These corrections for protein binding did not account for potency differences between serum and broth for either species; based on fu serum MICs, potency in serum was approximately fourfold greater than predicted for A. pleuropneumoniae and sixfold smaller than predicted for P. multocida. For both broth and serum and both bacterial species, MICs were also dependent on initial inoculum strength. The killing action of oxytetracycline had the characteristics of codependency for both A. pleuropneumoniae and P. multocida in both growth media. The in vitro potency of oxytetracycline in pig serum is likely to be closer to the in vivo plasma/serum concentration required for efficacy than potency estimated in broths. © 2017 The Authors. Journal of Veterinary Pharmacology and Therapeutics Published by John Wiley & Sons Ltd.

Evaluation of TECRA® broth, Bolton broth and direct plating for recovery of Campylobacter spp, from broiler carcass rinsates from several commercial processing plants

USDA-ARS?s Scientific Manuscript database

The purpose of this study was to compare a conventional culture broth method (Bolton enrichment broth containing lysed horse blood), a newly developed proprietary broth method (TECRA® Campylobacter enrichment) and direct plating for Campylobacter spp. recovery from chicken carcass rinses. Whole car...

Hybrid Vapor Stripping-Vapor Permeation Process for Recovery and Dehydration of 1-Butanol and Acetone/Butanol/Ethanol from Dilute Aqueous Solutions. Part 2. Experimental Validation with Simple Mixtures and Actual Fermentation Broth

EPA Science Inventory

BACKGROUND: In Part1 of this work, a process integrating vapor stripping, vapor compression, and a vapor permeation membrane separation step, Membrane Assisted Vapor Stripping (MAVS), was predicted to produce energy savings compared to traditional distillation systems for separat...

Antioxidant and antimicrobial activity of stingless bee bread and propolis extracts

NASA Astrophysics Data System (ADS)

Akhir, Rabieatul Adawieah Md; Bakar, Mohd Fadzelly Abu; Sanusi, Shuaibu Babaji

2017-10-01

Bee bread and propolis are by-products of honey bee. The main objective of this research was to investigate the antioxidant and antimicrobial activity of stingless bee bread and propolis extracted using 70% ethanol and n-hexane. The antioxidant activity of the sample extracts were determined by spectrophotometry analysis while for the antimicrobial activity, the sample extracts were analyzed using disc diffusion and broth dilution assays. For DPPH and ABTS assays, the results showed that ethanolic extract of bee bread showed the highest free radical scavenging (%) as compared to other samples. However, FRAP values for both hexanic extracts are higher as compared to the ethanolic extracts. For disc diffusion assay, the results showed that the ethanolic extract of bee bread and propolis as well as hexanic extract of propolis were able to inhibit all tested bacteria. Meanwhile, broth dilution assay showed minimum inhibition zone (MIC) ranging from <6.67 to 33.33 µL/mL. As the conclusion, both bee bread and propolis produced by stingless bee in this study displayed antioxidant and antimicrobial effect but there are different in the degree of antioxidant and antimicrobial activity exhibited between each of the samples.

Chemical and biological characterization of novel essential oils from Eremophila bignoniiflora (F. Muell) (Myoporaceae): a traditional Aboriginal Australian bush medicine.

PubMed

Sadgrove, Nicholas John; Hitchcock, Maria; Watson, Kenneth; Jones, Graham Lloyd

2013-10-01

Essential oils were extracted by hydrodistillation from the traditional Australian medicinal plant Eremophila bignoniiflora, characterized chemically and then screened for bioactivity. Characterization and quantification were completed using gas chromatography-mass spectrometry (GC-MS) and GC-flame ionization detection, respectively. Antimicrobial capacity was assessed using disc diffusion and micro-titre plate broth dilution and further characterized using thin layer chromatography followed by bioautography to assign activity to separated individual active components. Antifungal capacity was investigated using micro-titre plate broth dilution against pathogenic Trichophyton species. Free radical scavenging ability was assessed using the diphenylpicrylhydradyl reaction in methanol. The predominant components of the essential oil were fenchyl-acetate and bornyl-acetate. However, bioautography indicated antimicrobial ability to be largely linked to the less abundant, more polar constituents. Oils displayed only modest antifungal ability against pathogenic Trichophyton species associated with dermatophytosis, but moderate to high antimicrobial activity, particularly against the yeast Candida albicans and the bacteria Staphylococcus epidermidis. Essential oils exhibited relatively low free radical scavenging ability. Speculation over the role of essential oils in the traditional medicinal applications of E. bignoniiflora follows, exploring correlations between traditional use and investigated bioactivities. Copyright © 2012 John Wiley & Sons, Ltd.

Determination of Trimethoprim-Sulfamethoxazole Resistance in Streptococcus pneumoniae by Using the E Test with Mueller-Hinton Agar Supplemented with Sheep or Horse Blood May Be Unreliable

PubMed Central

Lovgren, M.; Dell’Acqua, L.; Palacio, R.; Echániz-Aviles, G.; Soto-Noguerón, A.; Castañeda, E.; Agudelo, C. I.; Heitmann, I.; Brandileone, M. C.; Zanella, R. C.; Rossi, A.; Pace, J.; Talbot, J. A.

1999-01-01

An international, multicenter study compared trimethoprim-sulfamethoxazole MICs for 743 Streptococcus pneumoniae isolates (107 to 244 isolates per country) by E test, using Mueller-Hinton agar supplemented with 5% defibrinated horse blood or 5% defibrinated sheep blood, with MICs determined by the National Committee for Clinical Laboratory Standards broth microdilution reference method. Agreement within 1 log2 dilution and minor error rates were 69.3 and 15.5%, respectively, on sheep blood-supplemented agar and 76.9 and 13.6%, respectively, with horse blood as the supplement. Significant interlaboratory variability was observed. E test may not be a reliable method for determining the resistance of pneumococci to trimethoprim-sulfamethoxazole. PMID:9854095

Screening antimicrobial activity of various extracts of Urtica dioica.

PubMed

Modarresi-Chahardehi, Amir; Ibrahim, Darah; Fariza-Sulaiman, Shaida; Mousavi, Leila

2012-12-01

Urtica dioica or stinging nettle is traditionally used as an herbal medicine in Western Asia. The current study represents the investigation of antimicrobial activity of U. dioica from nine crude extracts that were prepared using different organic solvents, obtained from two extraction methods: the Soxhlet extractor (Method I), which included the use of four solvents with ethyl acetate and hexane, or the sequential partitions (Method II) with a five solvent system (butanol). The antibacterial and antifungal activities of crude extracts were tested against 28 bacteria, three yeast strains and seven fungal isolates by the disc diffusion and broth dilution methods. Amoxicillin was used as positive control for bacteria strains, vancomycin for Streptococcus sp., miconazole nitrate (30 microg/mL) as positive control for fungi and yeast, and pure methanol (v/v) as negative control. The disc diffusion assay was used to determine the sensitivity of the samples, whilst the broth dilution method was used for the determination of the minimal inhibition concentration (MIC). The ethyl acetate and hexane extract from extraction method I (EA I and HE I) exhibited highest inhibition against some pathogenic bacteria such as Bacillus cereus, MRSA and Vibrio parahaemolyticus. A selection of extracts that showed some activity was further tested for the MIC and minimal bactericidal concentrations (MBC). MIC values of Bacillus subtilis and Methicillin-resistant Staphylococcus aureus (MRSA) using butanol extract of extraction method II (BE II) were 8.33 and 16.33mg/mL, respectively; while the MIC value using ethyl acetate extract of extraction method II (EAE II) for Vibrio parahaemolyticus was 0.13mg/mL. Our study showed that 47.06% of extracts inhibited Gram-negative (8 out of 17), and 63.63% of extracts also inhibited Gram-positive bacteria (7 out of 11); besides, statistically the frequency of antimicrobial activity was 13.45% (35 out of 342) which in this among 21.71% belongs to antimicrobial activity extracts from extraction method I (33 out of 152 of crude extracts) and 6.82% from extraction method II (13 out of 190 of crude extracts). However, crude extracts from method I exhibited better antimicrobial activity against the Gram-positive bacteria than the Gram-negative bacteria. The positive results on medicinal plants screening for antibacterial activity constitutes primary information for further phytochemical and pharmacological studies. Therefore, the extracts could be suitable as antimicrobial agents in pharmaceutical and food industry.

[Effect of Pseudomonas aeruginosa melanin on antibiotic activity].

PubMed

Rozhavin, M A

1978-08-01

The properties of microbial melanines are very diverse. Melanine of P. aeruginosa is little studied. The pigment was isolated from a strain of P. aeruginosa possessing all characteristic properties of the species. Interaction of P. aeruginosa melanine with various antibiotics was determined by the method of serial dilutions in beaf-peptone broth, using Staph. aureus 209 as a test-microbe, which was added to the medium in an amount of 10(6) cells to each tube. It was found that P. aeruginosa melanine differed from DOPA-melanine in a concentration of 1 mg/ml and did not change the activity of penicillin, tetracycline, oleandomycin, kanamycin and gentamicin with respect to Staph. aureus.

Hygiene quality and presence of ESBL-producing Escherichia coli in raw food diets for dogs

PubMed Central

Nilsson, Oskar

2015-01-01

Background Raw food diets are popular among some dog owners, even though there are concerns regarding the infectious disease risk and public health implications. Hence, the two aims of this study were to investigate the hygiene quality of raw food diets for dogs in the Swedish market and if Escherichia coli with transferable resistance to extended spectrum cephalosporins (ESC) was present in such products. Methods Samples of raw food diets were suspended and further diluted in 0.9% saline. Appropriate dilutions were 1) cultured on Petrifilm™SEC to quantify the amount of E. coli in the samples and 2) mixed with cefotaxime to a final concentration of 1 mg/L and cultured on Petrifilm™SEC to quantify the amount of ESC-resistant E. coli in the samples. Furthermore, undiluted suspensions were mixed 1:1 with double strength MacConkey broth with cefotaxime, enriched overnight and finally cultured on MacConkey agar with cefotaxime (1 mg/L). Suspected ESC-resistant E. coli were screened by PCR for genes encoding extended spectrum beta lactamases and plasmid-mediated AmpC and their susceptibility to a panel of antimicrobials was performed by broth microdilution using VetMIC GN-mo. Results Escherichia coli was isolated from all samples (n=39) and ESC-resistant E. coli was isolated from nine samples (23%). All ESC-resistant E. coli were PCR-positive for the bla CMY-2 group and only one of them was also resistant to a non-beta-lactam antibiotic. Conclusion The results of this study indicate that raw food diets could be a source of ESC-resistant E. coli to dogs and highlight the need for maintaining good hygiene when handling these products to prevent infection. PMID:26490763

Antimicrobial Susceptibility of Udder Pathogens Isolated from Dairy Herds in the West Littoral Region of Uruguay

PubMed Central

2002-01-01

A total of 522 strains belonging to streptococci, enterococci and staphylococci isolated from sub-clinical and clinical cases of bovine mastitis from the west littoral region of Uruguay were analysed for their susceptibility to several antimicrobial agents. The susceptibility patterns were studied by agar disk diffusion methods (ADDM) and broth micro-dilution to determine the minimum inhibitory concentration (MIC). The concentration that inhibits 90% (MIC90) of the analysed strains reported in micrograms per millilitre, for Staphylococcus aureus were > 8, 8, ≤ 0.5, ≤ 4, ≤ 1, ≤ 0.5, > 64, ≤ 0.25, 0.5, ≤ 1 and ≤ 1 to penicillin, ampicillin, oxacillin, cephalotin, gentamicin, erythromycin, oxitetracycline, enrofloxacin, trimethoprim/sulfamethoxazole, neomycin, and clindamycin, respectively. Coagulase-negative staphylococci (CNS) had different values for penicillin (4) and ampicillin (2), while the other antimicrobial agents had the same MIC90 values as reported for S. aureus. The MIC90 values for streptococci were 0.12, 0.25, ≤ 4, 16, ≤ 0.25, 0.5, 0.25 for penicillin, ampicillin, cephalotin, gentamicin, erythromycin, oxytetracycline and trimethoprim-sulfamethoxazole, whereas MIC90 for enterococci were 4, 4, 4, ≤ 0.5, 2, > 8 for penicillin, ampicillin, gentamicin, erythromycin, oxytetracycline and trimethoprim-sulfamethoxazole, respectively. Of 336 strains of S. aureus, 160 (47.6%) were resistant to penicillin. For 41 CNS strains, 10 (27%) presented penicillin-resistance. All the streptococcal strains were susceptible to penicillin, while 3 (7%) of the 43 enteroccocal strains were resistant. Non significant statistical differences were found between the results obtained by ADDM and broth micro-dilution for classifying bacterial isolates as susceptible or resistant according to the National Committee of Clinical Laboratory Standards. PMID:12071114

Relative effectiveness of the Bacteriological Analytical Manual method for the recovery of Salmonella from whole cantaloupes and cantaloupe rinses with selected preenrichment media and rapid methods.

PubMed

Hammack, Thomas S; Valentin-Bon, Iris E; Jacobson, Andrew P; Andrews, Wallace H

2004-05-01

Soak and rinse methods were compared for the recovery of Salmonella from whole cantaloupes. Cantaloupes were surface inoculated with Salmonella cell suspensions and stored for 4 days at 2 to 6 degrees C. Cantaloupes were placed in sterile plastic bags with a nonselective preenrichment broth at a 1:1.5 cantaloupe weight-to-broth volume ratio. The cantaloupe broths were shaken for 5 min at 100 rpm after which 25-ml aliquots (rinse) were removed from the bags. The 25-ml rinses were preenriched in 225-ml portions of the same uninoculated broth type at 35 degrees C for 24 h (rinse method). The remaining cantaloupe broths were incubated at 35 degrees C for 24 h (soak method). The preenrichment broths used were buffered peptone water (BPW), modified BPW, lactose (LAC) broth, and Universal Preenrichment (UP) broth. The Bacteriological Analytical Manual Salmonella culture method was compared with the following rapid methods: the TECRA Unique Salmonella method, the VIDAS ICS/SLM method, and the VIDAS SLM method. The soak method detected significantly more Salmonella-positive cantaloupes (P < 0.05) than did the rinse method: 367 Salmonella-positive cantaloupes of 540 test cantaloupes by the soak method and 24 Salmonella-positive cantaloupes of 540 test cantaloupes by the rinse method. Overall, BPW, LAC, and UP broths were equivalent for the recovery of Salmonella from cantaloupes. Both the VIDAS ICS/SLM and TECRA Unique Salmonella methods detected significantly fewer Salmonella-positive cantaloupes than did the culture method: the VIDAS ICS/SLM method detected 23 of 50 Salmonella-positive cantaloupes (60 tested) and the TECRA Unique Salmonella method detected 16 of 29 Salmonella-positive cantaloupes (60 tested). The VIDAS SLM and culture methods were equivalent: both methods detected 37 of 37 Salmonella-positive cantaloupes (60 tested).

A novel 96-well gel-based assay for determining antifungal activity against filamentous fungi.

PubMed

Troskie, Anscha Mari; Vlok, Nicolas Maré; Rautenbach, Marina

2012-12-01

In recent years the global rise in antibiotic resistance and environmental consciousness lead to a renewed fervour to find and develop novel antibiotics, including antifungals. However, the influence of the environment on antifungal activity is often disregarded and many in vitro assays may cause the activity of certain antifungals to be overestimated or underestimated. The general antifungal test assays that are economically accessible to the majority of scientists primarily rely on visual examination or on spectrophotometric analysis. The effect of certain morphogenic antifungals, which may lead to hyperbranching of filamentous fungi, unfortunately renders these methods unreliable. To minimise the difficulties experienced as a result of hyperbranching, we developed a straightforward, economical 96-well gel-based method, independent of spectrophotometric analysis, for highly repeatable determination of antifungal activity. For the calculation of inhibition parameters, this method relies on the visualisation of assay results by digitisation. The antifungal activity results from our novel micro-gel dilution assay are comparable to that of the micro-broth dilution assay used as standard reference test of The Clinical and Laboratory Standard Institute. Furthermore, our economical assay is multifunctional as it permits microscopic analysis of the preserved assay results, as well as rendering highly reliable data. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of Food Residues in Biofilm Formation on Stainless Steel and Polystyrene Surfaces by Salmonella enterica Strains Isolated from Poultry Houses.

PubMed

Paz-Méndez, Alba María; Lamas, Alexandre; Vázquez, Beatriz; Miranda, José Manuel; Cepeda, Alberto; Franco, Carlos Manuel

2017-11-29

Salmonella spp. is a major food-borne pathogen around the world. The ability of Salmonella to produce biofilm is one of the main obstacles in reducing the prevalence of these bacteria in the food chain. Most of Salmonella biofilm studies found in the literature used laboratory growth media. However, in the food chain, food residues are the principal source of nutrients of Salmonella . In this study, the biofilm formation, morphotype, and motility of 13 Salmonella strains belonging to three different subspecies and isolated from poultry houses was evaluated. To simulate food chain conditions, four different growth media (Tryptic Soy Broth at 1/20 dilution, milk at 1/20 dilution, tomato juice, and chicken meat juice), two different surfaces (stainless steel and polystyrene) and two temperatures (6 °C and 22 °C) were used to evaluate the biofilm formation. The morphotype, motility, and biofilm formation of Salmonella was temperature-dependent. Biofilm formation was significantly higher with 1/20 Tryptic Soy Broth in all the surfaces and temperatures tested, in comparison with the other growth media. The laboratory growth medium 1/20 Tryptic Soy Broth enhanced biofilm formation in Salmonella . This could explain the great differences in biofilm formation found between this growth medium and food residues. However, Salmonella strains were able to produce biofilm on the presence of food residues in all the conditions tested. Therefore, the Salmonella strain can use food residues to produce biofilm on common surfaces of the food chain. More studies combining more strains and food residues are necessary to fully understand the mechanism used by Salmonella to produce biofilm on the presence of these sources of nutrients.

Effect of Food Residues in Biofilm Formation on Stainless Steel and Polystyrene Surfaces by Salmonella enterica Strains Isolated from Poultry Houses

PubMed Central

Paz-Méndez, Alba María; Vázquez, Beatriz; Cepeda, Alberto; Franco, Carlos Manuel

2017-01-01

Salmonella spp. is a major food-borne pathogen around the world. The ability of Salmonella to produce biofilm is one of the main obstacles in reducing the prevalence of these bacteria in the food chain. Most of Salmonella biofilm studies found in the literature used laboratory growth media. However, in the food chain, food residues are the principal source of nutrients of Salmonella. In this study, the biofilm formation, morphotype, and motility of 13 Salmonella strains belonging to three different subspecies and isolated from poultry houses was evaluated. To simulate food chain conditions, four different growth media (Tryptic Soy Broth at 1/20 dilution, milk at 1/20 dilution, tomato juice, and chicken meat juice), two different surfaces (stainless steel and polystyrene) and two temperatures (6 °C and 22 °C) were used to evaluate the biofilm formation. The morphotype, motility, and biofilm formation of Salmonella was temperature-dependent. Biofilm formation was significantly higher with 1/20 Tryptic Soy Broth in all the surfaces and temperatures tested, in comparison with the other growth media. The laboratory growth medium 1/20 Tryptic Soy Broth enhanced biofilm formation in Salmonella. This could explain the great differences in biofilm formation found between this growth medium and food residues. However, Salmonella strains were able to produce biofilm on the presence of food residues in all the conditions tested. Therefore, the Salmonella strain can use food residues to produce biofilm on common surfaces of the food chain. More studies combining more strains and food residues are necessary to fully understand the mechanism used by Salmonella to produce biofilm on the presence of these sources of nutrients. PMID:29186017

The ability of selected plant essential oils to enhance the action of recommended antibiotics against pathogenic wound bacteria.

PubMed

Sienkiewicz, Monika; Łysakowska, Monika; Kowalczyk, Edward; Szymańska, Grażyna; Kochan, Ewa; Krukowska, Jolanta; Olszewski, Jurek; Zielińska-Bliźniewska, Hanna

2017-03-01

The aim of this work was to characterize the ability of essential oils to support antibiotics against pathogenic bacteria in wounds. Gram-positive and Gram-negative bacteria obtained from wound infections were identified according to standard microbiological methods. Essential oils were analysed by GC-FID-MS. The susceptibility of bacteria to antibiotics, essential oils and their combination was assessed using the disc-diffusion method. The Minimal Inhibitory Concentration and Minimum Bactericidal Concentration of the essential oils were established by the micro-dilution broth method. Although cinnamon, clove, thyme and lavender essential oils were found to have the greatest antibacterial activity when used alone, the greatest additive and synergistic effects against pathogenic wound bacteria in combination with recommended antibiotics were demonstrated by basil, clary sage and rosemary oils. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Continuous cultivation approach for fermentative succinic acid production from crude glycerol by Basfia succiniciproducens DD1.

PubMed

Scholten, Edzard; Renz, Torsten; Thomas, Jochen

2009-12-01

A continuous cultivation process for the fermentative production of succinic acid from glycerol with the recently isolated bacterium Basfia succiniciproducens DD1 was developed. Crude glycerol (5.1 g l(-1)) was used as C-source and NH(4)OH as N-source and pH-control agent. The problem of wall growth was solved by transfers of the cultivation broth into an empty identical fermentor. The resulting continuous cultivation process was maintained for more than 80 days. Glycerol-limited steady states were established for dilution rates between 0.004 and 0.018 h(-1). Higher dilution rates resulted in glycerol accumulation. Succinic acid concentrations, productivities, yields and specific productivities increased with increasing dilution rates: at 0.018 h(-1) the highest values were 5.21 g l(-1), 0.094 g l(-1) h(-1), 1.02 g g(-1) and 0.375 g g(-1) h(-1), respectively.

Antimicrobial Susceptibility of Haemophilus parainfluenzae

PubMed Central

Mayo, Joan B.; McCarthy, Laurence R.

1977-01-01

Fifty random clinical isolates of Haemophilus parainfluenzae were tested for their susceptibility to 10 antibiotics by a microtiter broth dilution method. Three of the strains tested were resistant to ampicillin, whereas eight were resistant to tetracycline. All strains tested were susceptible to chloramphenicol, kanamycin, gentamicin, cephalothin, and colistin. The ranges of minimal inhibitory concentrations for the three remaining antibiotics were: 0.5 to ≥128 μg of penicillin G per ml, 0.03 to 4 μg of carbenicillin per ml, and 1 to 16 μg of erythromycin per ml. Elevated minimal inhibitory concentrations for penicillin and carbenicillin were noted for the three ampicillin-resistant strains. Tests for beta-lactamase production demonstrated the presence of this enzyme in each of the three ampicillin-resistant strains. PMID:587028

Differential bacteriophage mortality on exposure to copper.

PubMed

Li, Jinyu; Dennehy, John J

2011-10-01

Many studies report that copper can be used to control microbial growth, including that of viruses. We determined the rates of copper-mediated inactivation for a wide range of bacteriophages. We used two methods to test the effect of copper on bacteriophage survival. One method involved placing small volumes of bacteriophage lysate on copper and stainless steel coupons. Following exposure, metal coupons were rinsed with lysogeny broth, and the resulting fluid was serially diluted and plated on agar with the corresponding bacterial host. The second method involved adding copper sulfate (CuSO(4)) to bacteriophage lysates to a final concentration of 5 mM. Aliquots were removed from the mixture, serially diluted, and plated with the appropriate bacterial host. Significant mortality was observed among the double-stranded RNA (dsRNA) bacteriophages Φ6 and Φ8, the single-stranded RNA (ssRNA) bacteriophage PP7, the ssDNA bacteriophage ΦX174, and the dsDNA bacteriophage PM2. However, the dsDNA bacteriophages PRD1, T4, and λ were relatively unaffected by copper. Interestingly, lipid-containing bacteriophages were most susceptible to copper toxicity. In addition, in the first experimental method, the pattern of bacteriophage Φ6 survival over time showed a plateau in mortality after lysates dried out. This finding suggests that copper's effect on bacteriophage is mediated by the presence of water.

Antibacterial activity study of Attacus atlas cocoon against Staphylococcus aureus and Escherichia coli with diffusion and dilution method

NASA Astrophysics Data System (ADS)

Aminah; Nugraheni, E. R.; Yugatama, A.

2018-03-01

The aim of this study was to evaluate the antibacterial activity from Attacus atlas cocoon extract against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) with 3 diffferent solvents polar, semi-polar and non polar which was ethanol, ethyl acetate and chloroform, also to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extract. Cocoon was extracted with maceration method using 3 solvents with ratio of sample and solvent 1:10. Antibacterial activity of the Extracts obtained was evaluated with Agar disk diffusion method. The best result was then continued to determine the MIC and MBC of the extract using broth macro-dilution method. The results show that each of the extracts have antibacterial activity with broad spectrum against two different type of bacteria at concentration of 1 g/mL with different clear zone between these extracts. Clear zone from the biggest to the smallest against Escherichia coli was ethyl acetate (10.5 mm), chloroform (9 mm) and ethanol (8 mm). While against Staphylococcus aureus, was obtained by chloroform (12.5 mm), ethyl acetate (10.5 mm) and ethanol (7 mm). The MIC value of extracts can not be determine. The smallest MBC value against both bacteria was obtained by ethyl acetate with concentration of 3.125% b/v as a bactericidal.

Native Brazilian plants against nosocomial infections: a critical review on their potential and the antimicrobial methodology.

PubMed

H Moreno, Paulo Roberto; da Costa-Issa, Fabiana Inácio; Rajca-Ferreira, Agnieszka K; Pereira, Marcos A A; Kaneko, Telma M

2013-01-01

The growing incidences of drug-resistant pathogens have increased the attention on several medicinal plants and their metabolites for antimicrobial properties. These pathogens are the main cause of nosocomial infections which led to an increasing mortality among hospitalized patients. Taking into consideration those factors, this paper reviews the state-of-the-art of the research on antibacterial agents from native Brazilian plant species related to nosocomial infections as well as the current methods used in the investigations of the antimicrobial activity and points out the differences in techniques employed by the authors. The antimicrobial assays most frequently used were broth microdilution, agar diffusion, agar dilution and bioautography. The broth microdilution method should be the method of choice for testing new antimicrobial agents from plant extracts or isolated compounds due to its advantages. At the moment, only a small part of the rich Brazilian flora has been investigated for antimicrobial activity, mostly with unfractionated extracts presenting a weak or moderate antibacterial activity. The combination of crude extract with conventional antibiotics represents a largely unexploited new form of chemotherapy with novel and multiple mechanisms of action that can overcome microbial resistance that needs to be further investigated. The antibacterial activity of essential oil vapours might also be an interesting alternative treatment of hospital environment due to their ability in preventing biofilm formation. However, in both alternatives more studies should be done on their mode of action and toxicological effects in order to optimize their use.

H. pylori in the pathogenesis of duodenal ulcer: interaction between duodenal acid load, bile, and H. pylori.

PubMed

Graham, D Y; Osato, M S

2000-01-01

Helicobacter pylori (H. pylori) growth is inhibited by bile yet it can grow in the duodenal bulb and cause ulcer disease. The aim of this study was to test the effect of bile on H. pylori viability and growth and to determine whether acidification of bile reduces its inhibitory activity. Fresh human bile was collected at laparotomy and tested for inhibitory activity of H. pylori using broth dilution assays. Six clinical isolates of H. pylori obtained from patients with duodenal ulcer were used for each experiment. The bile was diluted from 1:3 to 1:192; its inhibitory effect on H. pylori was tested before and after acidification, treatment with cholestyramine, or chloroform. Bile was acidified to a pH of 2-6, centrifuged at 8000 rpm for 20 min to remove precipitated bile acids, and the supernatant pH readjusted. Controls included BHI broth without bile (positive control) and bile that was acidified to pH 2 and neutralized without centrifugation. Human bile inhibited H. pylori growth in a dose dependent manner. Growth of all strains was supported for all strains only at a dilution of 1:192. In contrast, after acidification to pH < or =5 and centrifugation to remove precipitated bile acids, all strains grew at a bile dilution of 1:12. Neither chloroform extraction of lipids, nor acidification without centrifugation removed the inhibitory action of bile. In contrast, cholestyramine sequestration of bile acids completely removed all inhibitory activity. The duodenal acid load may be the critical factor to explain the ability of H. pylori to colonize the duodenal bulb by precipitating glycine-conjugated bile salts. The combination of a high duodenal acid load and H. pylori infection is likely the critical event in the pathogenesis of H. pylori-related duodenal ulcer disease.

Comparative evaluation of antibacterial activity of caffeic acid phenethyl ester and PLGA nanoparticle formulation by different methods

NASA Astrophysics Data System (ADS)

Arasoglu, Tülin; Derman, Serap; Mansuroglu, Banu

2016-01-01

The aim of the present study was to evaluate the antimicrobial activity of nanoparticle and free formulations of the CAPE compound using different methods and comparing the results in the literature for the first time. In parallel with this purpose, encapsulation of CAPE with the PLGA nanoparticle system (CAPE-PLGA-NPs) and characterization of nanoparticles were carried out. Afterwards, antimicrobial activity of free CAPE and CAPE-PLGA-NPs was determined using agar well diffusion, disk diffusion, broth microdilution and reduction percentage methods. P. aeroginosa, E. coli, S. aureus and methicillin-resistant S. aureus (MRSA) were chosen as model bacteria since they have different cell wall structures. CAPE-PLGA-NPs within the range of 214.0 ± 8.80 nm particle size and with an encapsulation efficiency of 91.59 ± 4.97% were prepared using the oil-in-water (o-w) single-emulsion solvent evaporation method. The microbiological results indicated that free CAPE did not have any antimicrobial activity in any of the applied methods whereas CAPE-PLGA-NPs had significant antimicrobial activity in both broth dilution and reduction percentage methods. CAPE-PLGA-NPs showed moderate antimicrobial activity against S. aureus and MRSA strains particularly in hourly measurements at 30.63 and 61.25 μg ml-1 concentrations (both p < 0.05), whereas they failed to show antimicrobial activity against Gram-negative bacteria (P. aeroginosa and E. coli, p > 0.05). In the reduction percentage method, in which the highest results of antimicrobial activity were obtained, it was observed that the antimicrobial effect on S. aureus was more long-standing (3 days) and higher in reduction percentage (over 90%). The appearance of antibacterial activity of CAPE-PLGA-NPs may be related to higher penetration into cells due to low solubility of free CAPE in the aqueous medium. Additionally, the biocompatible and biodegradable PLGA nanoparticles could be an alternative to solvents such as ethanol, methanol or DMSO. Consequently, obtained results show that the method of selection is extremely important and will influence the results. Thus, broth microdilution and reduction percentage methods can be recommended as reliable and useful screening methods for determination of antimicrobial activity of PLGA nanoparticle formulations used particularly in drug delivery systems compared to both agar well and disk diffusion methods.

Early Recovery of Salmonella from Food Using a 6-Hour Non-selective Pre-enrichment and Reformulation of Tetrathionate Broth.

PubMed

Daquigan, Ninalynn; Grim, Christopher J; White, James R; Hanes, Darcy E; Jarvis, Karen G

2016-01-01

Culture based methods are commonly employed to detect pathogens in food and environmental samples. These methods are time consuming and complex, requiring multiple non-selective and selective enrichment broths, and usually take at least 1 week to recover and identify pathogens. Improving pathogen detection in foods is a primary goal for regulatory agencies and industry. Salmonella detection in food relies on a series of culture steps in broth formulations optimized to resuscitate Salmonella and reduce the abundance of competitive bacteria. Examples of non-selective pre-enrichment broths used to isolate Salmonella from food include Lactose, Universal Pre-enrichment, BPW, and Trypticase Soy broths. Tetrathionate (TT) and Rappaport-Vassiliadis (RV) broths are employed after a 24-h non-selective enrichment to select for Salmonella and hamper the growth of competitive bacteria. In this study, we tested a new formulation of TT broth that lacks brilliant green dye and has lower levels of TT . We employed this TT broth formulation in conjunction with a 6-h non-selective pre-enrichment period and determined that Salmonella recovery was possible one day earlier than standard food culture methods. We tested the shortened culture method in different non-selective enrichment broths, enumerated Salmonella in the non-selective enrichments, and used 16S rRNA gene sequencing to determine the proportional abundances of Salmonella in the TT and RV selective enrichments. Together these data revealed that a 6-h non-selective pre-enrichment reduces the levels of competitive bacteria inoculated into the selective TT and RV broths, enabling the recovery of Salmonella 1 day earlier than standard culture enrichment methods.

Antibacterial activity of vegetables and juices.

PubMed

Lee, Yee-Lean; Cesario, Thomas; Wang, Yang; Shanbrom, Edward; Thrupp, Lauri

2003-01-01

We evaluated the antibacterial activities of various fruit and vegetable extracts on common potential pathogens including antibiotic-resistant strains. Standardized bacterial inocula were added to serial dilutions of sterile vegetable and fruit extracts in broth, with final bacterial concentrations of 10(4-5) cells/mL. After overnight incubation at 35 degrees C, antibacterial activity was measured by minimum inhibitory and minimum bactericidal dilutions (for raw juices) or concentrations (for tea). Among the vegetable and fruit extracts tested, all green vegetables showed no antibacterial activity on Staphylococcus epidermidis and Klebsiella pneumoniae. All purple and red vegetable and fruit juices had antibacterial activities in dilutions ranging from 1:2 to 1:16. Garlic juice had significant activity, with bactericidal action in dilutions ranging up to 1:128 of the original juice. Tea also had significant activity, with bactericidal action in concentrations ranging up to 1.6 mg/mL, against a spectrum of pathogens including resistant strains such as methicillin- and ciprofloxacin-resistant staphylococci, vancomycin-resistant enterococci, and ciprofloxacin-resistant Pseudomonas aeruginosa. Tea and garlic have the potential for exploration of broader applications as antibacterial agents.

[Growth of Clostridium botulinum in media with garlic (Allium sativum)].

PubMed

Giménez, M A; Solanes, R E; Giménez, D F

1988-01-01

The effect of garlic on the growth and toxin formation of Clostridium botulinum (GT) was studied in A) crude juice obtained from a pool of cloves by i) crushing, ii) pressing out and iii) filtration, and B) minced garlic (6 to 8 pieces per clove). For both, "white" and "red" garlic varieties were used. The juice (pH 5.7 to 6.0, for different batches) was activated 30 min at 37 degrees C and diluted (log 2) in PGY broth (g%: peptone (Difco) 1.0; glucose 0.5; yeast extract (Difco) 0.5; pH 7.3). A small drop from a 18 h at 37 degrees C chopped meat medium culture of a highly toxigenic autochthonous strain (110) of C. botulinum type A, was transferred to the juice dilutions, incubating anaerobically 15d at 37 degrees C. As a control of the inhibitory effect of the juice, four microorganisms were cultured 48 h at 37 degrees C in the juice dilutions (Table 1). Clove pieces were suspended to 50% (w/v) either in PGY broth or distilled water without pH adjustment. Aliquots were heated in water bath 15 min at 100 degrees C. After seeded with the A 110 strain, duplicate tubes and their controls were incubated 15 d at 37 degrees C in aerated and anaerobic conditions (Table 2). Titers of botulinum toxin were empirically estimated by the time to death of a pair of mice injected with 0.5 ml each, via IP, observed 72 h. Results are shown in tables 1 and 2. Garlic reduces (in undiluted juice, traces or 3 to 5 DL50/ml were recorded in separate experiments) but not inhibit GT.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibacterial activity of essential oils extracted from Satureja hortensis against selected clinical pathogens

NASA Astrophysics Data System (ADS)

Görmez, Arzu; Yanmiş, Derya; Bozari, Sedat; Gürkök, Sumeyra

2017-04-01

The antibiotic resistance of pathogenic microorganisms has become a worldwide concern to public health. To overcome the current resistance problem, new antimicrobial agents are extremely needed. The aim of the present study was to evaluate the antibacterial activity of Satureja hortensis essential oils against seven clinical pathogens. Chemical compositions of hydro distillated essential oils from S. hortensis were analyzed by GS-MS. The antibacterial activity was investigated against Corynebacterium diphtheria, Salmonella typhimurium, Serratia plymuthica Yersinia enterocolitica, Y. frederiksenii, Y. pseudotuberculosis and Vibrio cholerae by the use of disc diffusion method and broth micro dilution method. The minimum inhibitory concentration (MIC) values of essential oils were found as low as 7.81 µg/mL. Notably, essential oils of S. hortensis exhibited remarkable antimicrobial activities against the tested clinical pathogens. The results indicate that these essential oils can be used in treatment of different infectious diseases.

Synthesis, structural characterization, antimicrobial activities and theoretical investigations of some 4-(4-aminophenylsulfonyl) phenylimino) methyl)-4-(aryldiazenyl) phenol

NASA Astrophysics Data System (ADS)

Ghasemian, Motaleb; Kakanejadifard, Ali; Karami, Tahereh

2016-11-01

The azo-azomethine dyes with a different substitution have been designed from the reaction of 4,4‧-diaminodiphenyl sulfone with 2-hydroxy-5-(aryldiazenyl)benzaldehyde. The compounds have been characterized by elemental analysis, Mass, IR, UV-Vis, TGA-DTA and NMR spectroscopy. The solvatochromism behaviors, effects of substitution and pH on the electronic absorption spectra of dyes were evaluated. The in vitro antimicrobial activities were also screened for their potential for antibiotic activities by broth micro dilution method. Also, the optimum molecular geometries, molecular electrostatic potential (MEP), nucleus-independent chemical shift (NICS) and frontier molecular orbitals (FMO), vibrational spectra (IR) and electronic absorption (UV-Vis) spectra of the title compounds have been investigated with the help of DFT and TDDFT methods with 6-311 ++G(d,p) basis sets and PCM calculations. The results of the calculations show excellent agreement with the experimental value.

Vitamin D3 a new drug against Candida albicans.

PubMed

Bouzid, D; Merzouki, S; Bachiri, M; Ailane, S E; Zerroug, M M

2017-03-01

In this study, we demonstrate that vitamin D 3 had fungicidal activity against Candida albicans. The susceptibility of the yeast strain to the vitamin D 3 was investigated by the antimicrobial screening using modified agar diffusion method, minimum fungistatic concentrations (MFC s ) and minimum fungicide concentrations (MFC C ) of the vitamin D 3 were determined by the broth dilution method. The antifungal activity indicted that 100μg/ml of vitamin D 3 had a power inhibition in the growth of C. albicans with zone of inhibition 12.5mm and CMF C and CMF s were 1.58±0.0764μg/ml. These values indicate that vitamin D 3 can be considered to have fungicide activity. This antifungal effect may be due to the large lipsolubility of vitamin D 3 changing the integrity of the cell membrane. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Chemical composition and antimicrobial activities of essential oil from Wedelia urticifolia growing wild in Hunan Province, China.

PubMed

Hu, Junpeng; Jia, Mengmeng; Zhu, Liang

2018-04-18

The essential oil obtained from Wedelia urticifolia growing in Hunan Province, China, was analyzed for the first time by capillary GC and GC-MS. A total of 67 constituents, representing 98.68% in essential oil were identified. The major constituents of the oil were: α-pinene (8.85%), limonene (6.38%), carvacrol (6.15%), caryophyllene (6.08%), spathulenol (5.49%), sabinene (5.36%), camphor (4.34%). Antimicrobial potential of oil against bacterial strains (Pseudomonas aeruginosa, Escherichia coli and Bacillus subtilis, and Staphylococcus aureus), yeast strains (Hansenula anomala and Saccharomy cescerevisiae) and molds (Aspergillus niger, Chaetomium globosum, Mucor racemosus, and Monascus anka) was determined by disc diffusion method and broth micro dilution method, respectively. The oil exhibited promising antimicrobial effect as a diameter of zones of inhibition (16.8-24.9 mm). Minimum inhibitory concentration values of oil were ranged 62.5-1000 μg/mL.

In vitro antimicrobial activity of Pistacia lentiscus L. edible oil and phenolic extract.

PubMed

Mezni, F; Aouadhi, C; Khouja, M L; Khaldi, A; Maaroufi, A

2015-01-01

Pistacia lentiscus L. is known in some Tunisian forest area by its fixed oil used in traditional medicine as an antiseptic product. This investigation is the first to study the antimicrobial activity of P.lentiscus edible oil and its phenolic extract. Oil was extracted from fruits harvested from six provenances located in Tunisia. The antimicrobial activity was tested using disc diffusion assay and the broth dilution method. Kbouch and Sidi Zid oils were most efficient (p < 0.003) against, respectively, Staphylococcus aureus and Aspergillus niger with an inhibition zone of 9.33 mm. The phenolic extract had the largest spectrum of sensitive microorganisms. The minimum inhibitory concentration and minimum bactericidal concentration results showed that all strains were inhibited by both oil and extract.

Chemical composition and antimicrobial activity of Satureja hortensis and Trachyspermum copticum essential oil

PubMed Central

Mahboubi, M; Kazempour, N

2011-01-01

Background and Objectives The aim of this study was to evaluate the chemical composition and antimicrobial activity of Satureja hortensis and Trachyspermum copticum essential oils against different kinds of microorganisms in vitro. Material and Methods The antimicrobial activity was evaluated by micro broth dilution assay and the chemical composition of essential oils was analyzed by GC and GC/MS. Results Thymol, p-cymene, γ-terpinene and carvacrol were the main components of S. hortensis oil while thymol, γ-terpinene, and o-cymene were the major components of T. copticum oil. Two essential oils exhibited strong antimicrobial activity but the antimicrobial activity of T. copticum oil was higher than that of S. hortensis oil. Conclusion Thymol as a main component of oils plays an important role in antimicrobial activity. PMID:22530088

Oxidative production of xylonic acid using xylose in distillation stillage of cellulosic ethanol fermentation broth by Gluconobacter oxydans.

PubMed

Zhang, Hongsen; Han, Xushen; Wei, Chengxiang; Bao, Jie

2017-01-01

An oxidative production process of xylonic acid using xylose in distillation stillage of cellulosic ethanol fermentation broth was designed, experimentally investigated, and evaluated. Dry dilute acid pretreated and biodetoxified corn stover was simultaneously saccharified and fermented into 59.80g/L of ethanol (no xylose utilization). 65.39g/L of xylose was obtained in the distillation stillage without any concentrating step after ethanol was distillated. Then the xylose was completely converted into 66.42g/L of xylonic acid by Gluconobacter oxydans. The rigorous Aspen Plus modeling shows that the wastewater generation and energy consumption was significantly reduced comparing to the previous xylonic acid production process using xylose in pretreatment liquid. This study provided a practical process option for xylonic acid production from lignocellulose feedstock with significant reduction of wastewater and energy consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Isolation of Salmonellae from Foods Samples

PubMed Central

Taylor, Welton I.; Silliker, John H.

1961-01-01

A comparison of various methods of enhancing frequency of Salmonella isolations revealed that inoculation of a second enrichment broth, with culture from the first, was no improvement over the single direct enrichment method. It was inferior to centrifugation. Selenite was observed to produce more positive isolations at 48 hr than at 24. No change occurred in tetrathionate. Reconstitution of dried albumen with water produced a significant increase in isolations over direct inoculation of enrichment broth in the case of tetrathionate but not selenite broth. Pre-enrichment in lactose broth before inoculation of enrichment media was vastly superior to reconstitution in water for both enrichment broths. A comparison of results obtained using dulcitol, mannitol, lactose and carbohydrate-free purple broths in pre-enrichment indicated that the carbohydrate added was immaterial. PMID:13920002

Evaluation of TECRA broth, Bolton broth, and direct plating for recovery of Campylobacter spp, from broiler carcass rinsates from commercial processing plants.

PubMed

Richardson, L J; Cox, N A; Bailey, J S; Berrang, M E; Cox, J M; Buhr, R J; Fedorka-Cray, P J; Harrison, M A

2009-05-01

The purpose of this study was to compare a conventional culture broth method (Bolton enrichment), a newly developed proprietary broth method (TECRA Campylobacter enrichment), and direct plating for recovery of Campylobacter spp. from chicken carcass rinsates. Whole carcass rinses were taken from 140 carcasses at rehang (immediately after defeathering but before evisceration) and from 140 carcasses at postchill from eight different processing plants in the United States. The rinsate samples were packed in ice and shipped overnight to the laboratory. Aliquots of the rinsate were transferred into Bolton and TECRA enrichment broths and were direct plated. Standard laboratory procedures with Campy-cefex plates were followed for recovery of Campylobacter spp. For rehang carcasses, 94% were positive for Campylobacter spp. with the TECRA enrichment broth and 74% were positive with the Bolton enrichment broth. For postchill carcasses, 74% were positive for Campylobacter spp. with the TECRA enrichment broth and 71% were positive with the Bolton enrichment broth. Compared with the Bolton enrichment broth, TECRA enrichment broth significantly suppressed non-Campylobacter microflora (P < 0.05). Overall, TECRA enrichment broth yielded an 11% higher total number of Campylobacter-positive samples compared with the Bolton enrichment broth. Campylobacter spp. detection in postchill samples was significantly greater (P < 0.05) by enrichment (84%) than by direct plating (19%). The high number of Campylobacter-positive samples obtained with all procedures indicated that 99% of the carcass rinsates obtained at rehang and 84% obtained at postchill contained Campylobacter spp.

False positive fecal coliform in biosolid samples assayed using A-1 medium.

PubMed

Baker, Katherine H; Redmond, Brady; Herson, Diane S

2005-01-01

Two most probable number (MPN) methods-lauryl tryptose broth with Escherichia coli broth confirmation and direct A-1 broth incubation (A-1)--were compared for the enumeration of fecal coliform in lime-treated biosolid. Fecal coliform numbers were significantly higher using the A-1 method. Analysis of positive A-1 tubes, however, indicated that a high percentage of these were false positives. Therefore, the use of A-1 broth for 40 CFR Part 503 Pathogen Reduction (CFR, 1993) compliance testing is not recommended.

Comparison of 7 culture methods for Salmonella serovar Enteritidis and Salmonella serovar Typhimurium isolation in poultry feces.

PubMed

Rodríguez, Francisco I; Procura, Francisco; Bueno, Dante J

2018-06-26

The present work compared 7 different culture methods and 3 selective-differential plating media for Salmonella ser. Enteritidis (SE) and S. ser. Typhimurium (ST) isolation using artificially contaminated poultry feces. The sensitivity (Se) and accuracy (AC) values increased when Modified Semisolid Rappaport Vassiliadis (MSRV) methods were used in place of the Tetrathionate (TT) or Tetrathionate Hajna broth (TTH) method in the enrichment step. However, there was no significant difference between the pre-enrichment incubation at 4 to 6 and 18 to 24 h for MSRV5 and MSRV24 methods, respectively. All Salmonella strains were recovered in the lowest dilutions tested for MSRV24 and 3 out of 4 for MSRV5 methods (2 to 10 cfu/25 g). The TT and TTH methods showed a detection limit between 2.2 × 101 and 1.0 × 106 cfu/25 g of fecal sample. The agreement was variable between the methods. However, there was a very good agreement between the MSRV5 and MSRV24 methods, and between tetrathionate direct (TTD, no pre-enrichment media used) and buffered peptone water 18 to 24 h Tetrathionate broth combination (TT24 method) for Salmonella strains. The 3 selective-differential plating media showed an agreement between fair and excellent. They performed a high Se and AC in the MSRV methods for Salmonella strains. There was a significant difference between center and periphery for MSRV methods, and there was a fair agreement between them for all strains. The MSRV methods are better than TT/TTH methods for the isolation of different strains of SE and ST in poultry fecal samples. The MSRV5 method can be used to reduce the time for the detection of SE and ST in these samples. Furthermore, a loopful of the periphery of the growth should be streaked onto differential-selective plating media, even in the absence of halo, to decrease the number of false negative results.

Salmonella testing of pooled pre-enrichment broth cultures for screening multiple food samples.

PubMed

Price, W R; Olsen, R A; Hunter, J E

1972-04-01

A method has been described for testing multiple food samples for Salmonella without loss in sensitivity. The method pools multiple pre-enrichment broth cultures into single enrichment broths. The subsequent stages of the Salmonella analysis are not altered. The method was found applicable to several dry food materials including nonfat dry milk, dried egg albumin, cocoa, cottonseed flour, wheat flour, and shredded coconut. As many as 25 pre-enrichment broth cultures were pooled without apparent loss in the sensitivity of Salmonella detection as compared to individual sample analysis. The procedure offers a simple, yet effective, way to increase sample capacity in the Salmonella testing of foods, particularly where a large proportion of samples ordinarily is negative. It also permits small portions of pre-enrichment broth cultures to be retained for subsequent individual analysis if positive tests are found. Salmonella testing of pooled pre-enrichment broths provides increased consumer protection for a given amount of analytical effort as compared to individual sample analysis.

Hybrid and Mixed Matrix Membranes for Separations from Fermentations

PubMed Central

Davey, Christopher John; Leak, David; Patterson, Darrell Alec

2016-01-01

Fermentations provide an alternative to fossil fuels for accessing a number of biofuel and chemical products from a variety of renewable and waste substrates. The recovery of these dilute fermentation products from the broth, however, can be incredibly energy intensive as a distillation process is generally involved and creates a barrier to commercialization. Membrane processes can provide a low energy aid/alternative for recovering these dilute fermentation products and reduce production costs. For these types of separations many current polymeric and inorganic membranes suffer from poor selectivity and high cost respectively. This paper reviews work in the production of novel mixed-matrix membranes (MMMs) for fermentative separations and those applicable to these separations. These membranes combine a trade-off of low-cost and processability of polymer membranes with the high selectivity of inorganic membranes. Work within the fields of nanofiltration, reverse osmosis and pervaporation has been discussed. The review shows that MMMs are currently providing some of the most high-performing membranes for these separations, with three areas for improvement identified: Further characterization and optimization of inorganic phase(s), Greater understanding of the compatibility between the polymer and inorganic phase(s), Improved methods for homogeneously dispersing the inorganic phase. PMID:26938567

Antimicrobial susceptibility testing of Mycobacterium tuberculosis complex for first and second line drugs by broth dilution in a microtiter plate format.

PubMed

Hall, Leslie; Jude, Kurt P; Clark, Shirley L; Wengenack, Nancy L

2011-06-24

The rapid detection of antimicrobial resistance is important in the effort to control the increase in resistant Mycobacterium tuberculosis (Mtb). Antimicrobial susceptibility testing (AST) of Mtb has traditionally been performed by the agar method of proportion or by macrobroth testing on an instrument such as the BACTEC (Becton Dickinson, Sparks, MD), VersaTREK (TREK Diagnostics, Cleveland, OH) or BacT/ALERT (bioMérieux, Hazelwood, MO). The agar proportion method, while considered the "gold" standard of AST, is labor intensive and requires calculation of resistance by performing colony counts on drug-containing agar as compared to drug-free agar. If there is ≥1% growth on the drug-containing medium as compared to drug-free medium, the organism is considered resistant to that drug. The macrobroth methods require instrumentation and test break point ("critical") drug concentrations for the first line drugs (isoniazid, ethambutol, rifampin, and pyrazinamide). The method described here is commercially available in a 96 well microtiter plate format [MYCOTB (TREK Diagnostics)] and contains increasing concentrations of 12 antimicrobials used for treatment of tuberculosis including both first (isoniazid, rifampin, ethambutol) and second line drugs (amikacin, cycloserine, ethionamide, kanamycin, moxifloxacin, ofloxacin, para-aminosalicylic acid, rifabutin, and streptomycin). Pyrazinamide, a first line drug, is not included in the microtiter plate due to its need for acidic test conditions. Advantages of the microtiter system include both ease of set up and faster turn around time (14 days) compared with traditional agar proportion (21 days). In addition, the plate can be set up from inoculum prepared using either broth or solid medium. Since the microtiter plate format is new and since Mtb presents unique safety challenges in the laboratory, this protocol will describe how to safely setup, incubate and read the microtiter plate.

Surface Enhanced Raman Spectroscopy for the Rapid Detection and Identification of Microbial Pathogens in Human Serum

DTIC Science & Technology

2014-12-11

and 1 mm depth. Bacterial culture and cell count determination Bacterial species of Acinetobacter baumannii (A. baumannii, ST-3), Escherichia coli...remove all broth components followed by a final resuspension of the pellet in ddH2O back to 1 OD. Cell count was determined by plating the 10 4 , 10 3...10 2 and 10 1 cell dilutions on TSB Nutrient Agar media. Colony forming units (CFU) were counted the following day to confirm bacterial species

Plating isolation of various catalase-negative microorganisms from soil

NASA Technical Reports Server (NTRS)

Labeda, D. P.; Hunt, C. M.; Casida, L. E., Jr.

1974-01-01

A unique plating procedure was developed that allows isolation, but not enumeration, of representatives of the catalase-negative soil microflora. The numbers recovered, however, are low as compared to the numbers recovered when the modified dilution-to-extinction isolation procedure is used. The latter procedure provides prolonged inoculation in sealed tubes containing a nutritionally rich broth medium over small submerged agar slants. In contrast, the plating procedure utilizes nutritionally minimal media and the shorter incubations mandated by the inherent problems associated with plating.

Evaluation of different selective media and culturing techniques for the quantification of Campylobacter ssp. from broiler litter.

PubMed

Kiess, A S; Parker, H M; McDaniel, C D

2010-08-01

Poultry is a major reservoir for Campylobacter, the leading cause of foodborne illness in the United States, but how broilers become initially colonized is still under debate. Broiler litter is a potential source, but the best technique for quantifying Campylobacter from litter is still unknown. Therefore, our objectives were to determine if certain media are more selective for quantifying Campylobacter and if enrichment allows for the detection of stressed or viable but nonculturable cells from broiler litter samples. In this trial, 5 media and 2 culturing techniques were used to enumerate Campylobacter from broiler litter. The media used were campy-Line agar (CLA), campy-cefex agar (CCA), modified CCA, Campylobacter agar plates (CAP), and modified charcoal cefoperazone deoxycholate agar. Litter samples were obtained from a commercial broiler house. Each sample was equally divided and diluted 10-fold into peptone, for direct plating, or 4-fold into Campylobacter enrichment broth. Samples diluted in peptone were direct-plated onto each media and incubated under microaerophilic conditions for 48 h at 42 degrees C. Samples diluted in enrichment broth were incubated under the same conditions for 24 h, then further diluted to 10-fold before plating. Plates from enriched samples were incubated for an additional 24 h after plating. After incubation, all plates (direct and enriched) were counted and presumptive positive colonies were confirmed using a Campylobacter latex agglutination kit. Results indicated that there was no difference in the ability of any of the selective media tested to grow Campylobacter. Direct-plated samples had a higher Campylobacter isolation rate compared with enriched samples. The CLA and CAP were able to suppress total bacterial growth better than modified charcoal cefoperazone deoxycholate, modified CCA, and CCA. The CLA and CAP were the only media able to detect total bacterial population shifts over time. In conclusion, it is important before making a final decision on a selective medium to consider the medium's ability to suppress total bacterial growth as well as isolate Campylobacter.

Effects of natural honey on polymicrobial culture of various human pathogens.

PubMed

Al-Waili, Noori S; Al-Waili, Faiza S; Akmal, Mohammed; Ali, Amjed; Salom, Khelod Y; Al Ghamdi, Ahmad A

2014-05-12

Honey has a wide range of antimicrobial activity. All previous studies have considered honey's effect on a single microbe. The present study investigated activity of honey towards a high dose of single or polymicrobial culture. 10 µl specimens of Staphylococcus aureus (S. aureus), Streptococcus pyogenes (S. pyogenes), Escherichia coli (E. coli) and Candida albicans (C. albicans) were cultured in 10 ml of 10-100% (wt/v) honey diluted in broth. Six types of polymicrobial microbial cultures were prepared by culturing the isolates with each other onto broth (control) and broth containing various concentrations of honey (10-100% wt/v). Microbial growth was assessed on solid plate media after 24 h incubation. Honey (30-70%) prevents growth of 10 µl specimens of all the isolates. Greater reduction in growth of E. coli was observed when cultured with S. aureus. Culturing of S. aureus with S. pyogenes, C. albicans, or E. coli increased its sensitivity to honey. S. aureus and S. pyogenes increased sensitivity of C. albicans to honey while E. coli and C. albicans decreased sensitivity of S. pyogenes. It might be concluded that honey prevents and inhibits growth of single and polymicrobial pathogenic cultures. Polymicrobial culture affects growth of the isolates and increases their sensitivity to honey.

Impact of recycling stillage on conversion of dilute sulfuric acid pretreated corn stover to ethanol.

PubMed

Mohagheghi, Ali; Schell, Daniel J

2010-04-01

Both the current corn starch to ethanol industry and the emerging lignocellulosic biofuels industry view recycling of spent fermentation broth or stillage as a method to reduce fresh water use. The objective of this study was to understand the impact of recycling stillage on conversion of corn stover to ethanol. Sugars in a dilute-acid pretreated corn stover hydrolysate were fermented to ethanol by the glucose-xylose fermenting bacteria Zymomonas mobilis 8b. Three serial fermentations were performed at two different initial sugar concentrations using either 10% or 25% of the stillage as makeup water for the next fermentation in the series. Serial fermentations were performed to achieve near steady state concentration of inhibitors and other compounds in the corn stover hydrolysate. Little impact on ethanol yields was seen at sugar concentrations equivalent to pretreated corn stover slurry at 15% (w/w) with 10% recycle of the stillage. However, ethanol yields became progressively poorer as the sugar concentration increased and fraction of the stillage recycled increased. At an equivalent corn stover slurry concentration of 20% with 25% recycled stillage the ethanol yield was only 5%. For this microorganism with dilute-acid pretreated corn stover, recycling a large fraction of the stillage had a significant negative impact on fermentation performance. Although this finding is of concern for biochemical-based lignocellulose conversion processes, other microorganism/pretreatment technology combinations will likely perform differently. (c) 2009 Wiley Periodicals, Inc.

In vitro antimicrobial activities of cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene against Mycoplasma hominis clinical isolates.

PubMed

Sleha, Radek; Mosio, Petra; Vydrzalova, Marketa; Jantovska, Alexandra; Bostikova, Vanda; Mazurova, Jaroslava

2014-06-01

The aim of this study was to evaluate the antimicrobial effects of five natural substances against 50 clinical isolates of Mycoplasma hominis. The in vitro activity of selected natural compounds, cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene, was investigated against 50 M. hominis isolates cultivated from cervical swabs by the broth dilution method. All showed valuable antimicrobial activity against the tested isolates. Oil from the bark of Cinnamomum zeylanicum (MBC90 = 500 µg/mL) however was found to be the most effective. Carvacrol (MBC90 = 600 µg/mL) and eugenol (MBC90 = 1000 µg/mL) also possessed strong antimycoplasmal activity. The results indicate that cinnamon bark oil, carvacrol and eugenol have strong antimycoplasmal activity and the potential for use as antimicrobial agents in the treatment of mycoplasmal infections.

Comparison of antimicrobial peptide purification via free-flow electrophoresis and gel filtration chromatography.

PubMed

Xia, Zhi-Jun; Liu, Zhen; Kong, Fan-Zhi; Fan, Liu-Yin; Xiao, Hua; Cao, Cheng-Xi

2017-12-01

Antimicrobial peptides (AMPs) are usually small and cationic biomolecules with broad-spectrum antimicrobial activities against pathogens. Purifying them from complex samples is essential to study their physiochemical properties. In this work, free-flow zone electrophoresis (FFZE) was utilized to purify AMPs from yeast fermentation broth. Meanwhile, gel filtration chromatography (GFC) was conducted for comparison. The separation efficiency was evaluated by SDS-PAGE analysis of the fractions from both methods. Our results demonstrated as follows: (i) FFZE had more than 30-fold higher processing capacity as compared with GFC; (ii) FFZE could achieve 87% purity and 89% recovery rate while in GFC these parameters were about 93 and 82%, respectively; (iii) the former had ∼2-fold dilution but the latter had ∼13-fold dilution. Furthermore, Tricine-SDS-PAGE, Native-PAGE, and gel IEF were carried out to characterize the purified AMPs. We found that two peptides existed as a pair with the molecular mass of ∼5.5 and 7.0 kDa, while the same pI 7.8. These two peptides were proved to have the antimicrobial activity through the standardized agar diffusion method. Therefore, FFZE could be used to continuously purify AMPs with high bioactivity, which will lead to its wide application in the clinical and pharmaceutical fields. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In-vitro activity of essential oils, in particular Melaleuca alternifolia (tea tree) oil and tea tree oil products, against Candida spp.

PubMed

Hammer, K A; Carson, C F; Riley, T V

1998-11-01

The in-vitro activity of a range of essential oils, including tea tree oil, against the yeast candida was examined. Of the 24 essential oils tested by the agar dilution method against Candida albicans ATCC 10231, three did not inhibit C. albicans at the highest concentration tested, which was 2.0% (v/v) oil. Sandalwood oil had the lowest MIC, inhibiting C. albicans at 0.06%. Melaleuca alternifolia (tea tree) oil was investigated for activity against 81 C. albicans isolates and 33 non-albicans Candida isolates. By the broth microdilution method, the minimum concentration of oil inhibiting 90% of isolates for both C. albicans and non-albicans Candida species was 0.25% (v/v). The minimum concentration of oil killing 90% of isolates was 0.25% for C. albicans and 0.5% for non-albicans Candida species. Fifty-seven Candida isolates were tested for sensitivity to tea tree oil by the agar dilution method; the minimum concentration of oil inhibiting 90% of isolates was 0.5%. Tests on three intra-vaginal tea tree oil products showed these products to have MICs and minimum fungicidal concentrations comparable to those of non-formulated tea tree oil, indicating that the tea tree oil contained in these products has retained its anticandidal activity. These data indicate that some essential oils are active against Candida spp., suggesting that they may be useful in the topical treatment of superficial candida infections.

Detection of amphotericin B resistance in Candida haemulonii and closely related species by use of the Etest, Vitek-2 yeast susceptibility system, and CLSI and EUCAST broth microdilution methods.

PubMed

Shin, Jong Hee; Kim, Mi-Na; Jang, Sook Jin; Ju, Min Young; Kim, Soo Hyun; Shin, Myung Geun; Suh, Soon Pal; Ryang, Dong Wook

2012-06-01

The emerging fungal pathogens Candida haemulonii and Candida pseudohaemulonii often show high-level resistance to amphotericin B (AMB). We compared the utilities of five antifungal susceptibility testing methods, i.e., the Etest using Mueller-Hinton agar supplemented with glucose and methylene blue (Etest-MH), the Etest using RPMI agar supplemented with glucose (Etest-RPG), the Vitek-2 yeast susceptibility system, and the Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution methods, for the detection of AMB-resistant isolates of C. haemulonii and closely related species. Thirty-eight clinical isolates (8 C. haemulonii, 10 C. pseudohaemulonii, and 20 Candida auris isolates) were analyzed. Of the 18 C. haemulonii and C. pseudohaemulonii isolates, 18, 15, 18, 10, and 9 exhibited AMB MICs of >1 μg/ml by the Etest-MH, Etest-RPG, Vitek-2, CLSI, and EUCAST methods, respectively. All 20 C. auris isolates showed AMB MICs of ≤1 μg/ml by all five methods. Of the methods, the Etest-MH generated the broadest distribution of AMB MICs for all 38 isolates and showed the best discrimination between the C. haemulonii and C. pseudohaemulonii isolates (4 to 32 μg/ml) and those of C. auris (0.125 to 0.5 μg/ml). Taking the Etest-MH as the reference method, the essential agreements (within two dilutions) for the Etest-RPG, Vitek-2, CLSI, and EUCAST methods were 84, 92, 55, and 55%, respectively; the categorical agreements were 92, 92, 79, and 76%, respectively. This study provides the first data on the efficacy of the Etest-MH and its excellent agreement with Vitek-2 for discriminating AMB-resistant from AMB-susceptible isolates of these Candida species.

Enhanced recovery of Salmonella from apple cider and apple juice with universal preenrichment broth.

PubMed

Hammack, Thomas S; Johnson, Mildred L; Jacobson, Andrew P; Andrews, Wallace H

2002-01-01

A comparison was made of the relative efficiencies of Universal Preenrichment (UP) broth and lactose broth for the recovery of a variety of Salmonella serovars from pasteurized and unpasteurized apple cider and pasteurized apple juice. Bulk portions of juice were contaminated with single Salmonella serovars at high and low levels of 0.4 and 0.04 CFU/mL, respectively. The juice was aged for a minimum of 5 days at 2-5 degrees C. On the day analysis was initiated, each of 20 test portions (25 mL) of the contaminated juice was preenriched in UP broth and in lactose broth. The Bacteriological Analytical Manual Salmonella culture method was followed thereafter. For pasteurized apple cider, UP broth recovered significantly (p < 0.05) more Salmonella-positive test portions than did lactose broth (112 and 75, respectively). For unpasteurized apple cider, UP broth recovered significantly more Salmonella-positive test portions than did lactose broth (326 and 221, respectively). For pasteurized apple juice, UP broth recovered more Salmonella-positive test portions than did lactose broth (93 and 81, respectively). However, this difference was not statistically significant. These results indicate that UP broth should replace lactose broth for the analysis of pasteurized and unpasteurized apple cider and pasteurized apple juice.

Antifungal screening of endophytic fungi from Ginkgo biloba for discovery of potent anti-phytopathogenic fungicides.

PubMed

Xiao, Yu; Li, Hong-Xia; Li, Cong; Wang, Jian-Xin; Li, Jun; Wang, Ming-Hua; Ye, Yong-Hao

2013-02-01

Many endophytic fungi have been found to synthesize bioactive compounds to defend host plants against pathogenic organisms. Here we performed anti-fungal bioassay of 80 endophytic fungi isolated from Ginkgo biloba. Fifteen endophytes were active against at least one of the selected fungi, Fusarium graminearum, Sclerotinia sclerotiorum and Phytophthora capsici, using the agar diffusion method. The most bioactive strain CDW7 was identified as Chaetomium globosum by microscopic examination and ITS rRNA gene sequence data. Culture broth of CDW7 diluted 3-fold completely inhibited the mycelial growth and conidia germination of F. graminearum in vitro. Therefore, Fusarium head blight, a common disease in wheat and barley associated with Fusarium spp., was used to test the anti-phytopathogenic activity in vivo. The fermentation broth of CDW7 resulted in a protective efficacy of 54.9% and curative efficacy of 48.8%. Followed by a bioassay-guided approach, 1,2-benzenedicarboxaldehyde-3,4,5-trihydroxy-6-methyl (flavipin) was isolated and demonstrated to significantly inhibit the growth of several plant-pathogenic fungi, especially F. graminearum with an EC(50) value of 0.73 μg mL(-1) comparable to the commonly used fungicide carbendazim, indicating that it could be used as a fungicide or as a lead compound of new fungicides. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Antibacterial Effect of Curcuma longa (Turmeric) Against Staphylococcus aureus and Escherichia coli.

PubMed

Afrose, R; Saha, S K; Banu, L A; Ahmed, A U; Shahidullah, A S; Gani, A; Sultana, S; Kabir, M R; Ali, M Y

2015-07-01

This observational study was conducted during the period from July 2010 to June 2011 in the Department of Pharmacology in the collaboration of Department of Microbiology, Mymensingh Medical College, Mymensingh to determine the profile of antibacterial effect of Crude Turmeric paste aqueous turmeric extract, and standard antibiotic Amikacin against Staphylococcus aureus and Escherichia coli. Three separate experiments were done e.g. (Expt- I) Inhibitory effect of Crude Turmeric paste incorporated into nutrient agar (NA) media, (Expt- II) Minimum inhibitory concentration of (a) Aqueous Turmeric extract and (b) Amikacin by broth dilution technique and (Expt-III) their subculture study in nutrient agar (NA) media for confirmation of respective results of previous experiments. Inhibitory effects were observed against the growth of Staph Aureus and Esch coli at 10% and 30% respectively of Crude Turmeric paste incorporated into NA media. The broth dilution technique was followed to determine the MIC of Aqueous Turmeric extract and Amikacin. The MIC of Aqueous Turmeric extract was 800 μg/ml against Staph aureus and that against Esch coli was 2000 μg/ml and the MIC of Amikacin was 10 μg/ml for both the bacteria. The MIC of Amikacin was the lowest in comparison to MIC of Aqueous Turmeric extract for complete inhibition of growth of Staph aureus and Esch coli. The subculture study showed similar results with that of previous experiments in terms of inhibitory effects of Crude Turmeric paste and MIC of Aqueous Turmeric extract and Amikacin against all of the organisms studied.

Pituitary adenylate cyclase-activating polypeptide is a potent broad-spectrum antimicrobial peptide: Structure-activity relationships.

PubMed

Starr, Charles G; Maderdrut, Jerome L; He, Jing; Coy, David H; Wimley, William C

2018-06-01

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a naturally occurring cationic peptide with potent immunosuppressant and cytoprotective activities. We now show that full length PACAP38 and to a lesser extent, the truncated form PACAP27, and the closely related vasoactive intestinal peptide (VIP) and secretin had antimicrobial activity against the Gram-negative bacteria Escherichia coli in the radial diffusion assay. PACAP38 was more potent than either the bovine neutrophil antimicrobial peptide indolicidin or the synthetic antimicrobial peptide ARVA against E. coli. PACAP38 also had activity against the Gram-positive bacteria Staphylococcus aureus in the same assay with comparable potency to indolicidin and ARVA. In the more stringent broth dilution assay, PACAP38 had moderate sterilizing activity against E. coli, and potent sterilizing activity against the Gram-negative bacteria Pseudomonas aeruginosa. PACAP27, VIP and secretin were much less active than PACAP38 in this assay. PACAP38 also had some activity against the Gram-positive bacteria Bacillus cereus in the broth dilution assay. Many exopeptidase-resistant analogs of PACAP38, including both receptor agonists and antagonists, had antimicrobial activities equal to, or better than PACAP38, in both assays. PACAP38 made the membranes of E. coli permeable to SYTOX Green, suggesting a classical membrane lytic mechanism. These data suggest that analogs of PACPAP38 with a wide range of useful biological activities can be made by judicious substitutions in the sequence. Copyright © 2018 Elsevier Inc. All rights reserved.

[Effect of biopesticide Pythium oligandrum broth on gummy stem blight in cucumber seedlings, animal health and plant growth].

PubMed

Geng, Mingming; Jia, Ruilian; Sui, Zongming; Huang, Jianguo

2016-07-04

Biopesticides are safe and environment friendly. We evaluated the biocontrol effect of Pythium oligandrum broth (POB) and its toxicity to animals and plant growth. Animal, antagonist, pot, and field experiments with mice, Mycosphaerella melonis, and cucumber seedlings were carried out to study animal toxicity, control of gummy stem blight, plant growth, fruit yield and quality with POB produced from self-isolated P. oligandrum CQ2010. Mouse showed normal weight, appearances, performances and no pathogenic changes in organs and tissues with a large amount of POB supplied by lavage. The inhibition rate of POB against M. melonis was 51.95%, similar to thiophanate methy (800 times dilution) but much higher than chlorothalonil (200 times dilution). Malondialdehyde concentration was reduced whereas activities of peroxidase and superoxide dismutase were stimulated in seedling leaves irrespective of POB supplied before and after pathogenic inoculation. POB also decreased the pathogenic incidence and disease index with relative control efficacy from 54.8% to 64.1%. Thus, POB could alleviate cell membrane damage caused by pathogenic microbes, stimulate physiological reactions related to disease defense, and increase disease-resistant abilities of plants. Moreover, POB increased chlorophyll content, root activity, and uptake of nitrogen, phosphorus and potassium, resulting in growth acceleration, fruit yield increment, and quality improvement. POB is safe to animals and could control gummy stem blight of cucumber seedlings, promote plant growth, increase fruit yield, and improve the qualities.

Rapid determination of lovastatin in the fermentation broth of Aspergillus terreus using dual-wavelength UV spectrophotometry.

PubMed

Li, Shi-Weng; Song, Hong-Ping; Leng, Yan

2014-01-01

Lovastatin, a hypocholesterolemic drug, is produced by submerged fermentation of Aspergillus terreus Thom (Trichocomaceae). High performance liquid chromatography is usually used to determine lovastatin in samples of the fermentation broth. However, this method is inconvenient and costly, especially in the context of high-throughput sample analysis. A direct and simple dual-wavelength ultraviolet spectrophotometric method for quantifying lovastatin in the fermentation broth of A. terreus was developed. A. terreus Z15-7 was used for all experiments. The liquid fermentation was conducted at 30 °C in a rotary shaker at 150 rpm for 15 d. Silica gel and neutral alumina column chromatography were used for the separation and purification of lovastatin from the fermentation broth. The limits of detection of lovastatin were 0.320 μg/ml in the lovastatin standard solution and 0.490 μg/ml in the fermentation broth sample and the limits of quantification of lovastatin were 1.265 μg/ml in the lovastatin standard solution and 3.955 μg/ml in the fermentation broth sample. The amounts of lovastatin in the fermentation broth ranged from 876.614 to 911.967 μg/ml, with relative standard deviations from 1.203 to 1.709%. The mean recoveries of lovastatin using silica gel and neutral alumina column chromatography were 84.2 ± 0.82 and 87.2 ± 0.21%, respectively. Dual-wavelength UV spectrophotometry is a rapid, sensitive, accurate, and convenient method for quantifying lovastatin in fermentation broth. Neutral alumina column chromatography is more efficient than silica gel column chromatography for the purification and determination lovastatin using the developed dual-wavelength UV spectrophotometry method.

Antimicrobial activity of fresh garlic juice: An in vitro study

PubMed Central

Yadav, Seema; Trivedi, Niyati A.; Bhatt, Jagat D.

2015-01-01

Introduction: Antimicrobial resistance has been a global concern. Currently, interest has been focused on exploring antimicrobial properties of plants and herbs. One such botanical is Allium sativum (garlic). Aim: To evaluate the antimicrobial activity of fresh juice of garlic. Materials and Methods: Varying concentrations of fresh garlic juice (FGJ) were tested for their antimicrobial activity against common pathogenic organisms isolated at SSG Hospital, Vadodara, using well diffusion method. Moreover, minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) of FGJ were tested using broth dilution method. Sensitivity pattern of the conventional antimicrobials against common pathogenic bacteria was tested using disc diffusion method. Results: FGJ produced dose-dependent increase in the zone of inhibition at a concentration of 10% and higher. MIC of FGJ against the pathogens ranged from 4% to 16% v/v whereas MLC value ranged from 4% to 32% v/v with Escherichia coli and Staphylococcus aureus spp. showed highest sensitivity. Conclusion: FGJ has definite antimicrobial activity against common pathogenic organisms isolated at SSG Hospital, Vadodara. Further studies are needed to find out the efficacy, safety, and kinetic data of its active ingredients. PMID:27011724

Anti-Candida activity and brine shrimp toxicity assay of Ganoderma boninense.

PubMed

Daruliza, K M A; Fernandez, L; Jegathambigai, R; Sasidharan, S

2012-01-01

Ganoderma (G.) boninense is a white rot fungus, which can be found in the palm oil tree. Several studies have shown that G. boninense has antimicrobial and antagonistic properties. However, there is limited information reported on antifungal properties especially on Candida (C) albicans. Hence, this study was conducted to determine the anti-Candida activity of G. boninense against C albicans. Crude methanolic extracts of G. boninense was obtained by maceration method with 70% methanol. Anti-Candida test was carried out using disc diffusion assay, broth dilution method, time killing profile and brine shrimp toxicity assay. Anti-Candida activity indicated that the mean zone of inhibition was 12.5 +/- 0.6 mm. The MIC value for C. albicans found to be 3.125 mg/ml. The result from time-killing profile showed that the growth of C albicans was inhibited hence decreases its exponential phase. For brine shrimp toxicity assay, the LC50 value was 3.59 mg/ml which proved that the extract of G. boninense is not toxic.

Lipid accumulation by pelletized culture of Mucor circinelloides on corn stover hydrolysate.

PubMed

Reis, Cristiano E R; Zhang, Jianguo; Hu, Bo

2014-09-01

Microbial oil accumulated by fungal cells is a potential feedstock for biodiesel production, and lignocellulosic materials can serve as the carbon source to support the fungal growth. The dilute acid pretreatment of corn stover can effectively break down its lignin structure, and this process generates a hydrolysate containing mostly xylose at very dilute concentration and numerous by-products that may significantly inhibit the cell growth. This study utilized corn stover hydrolysate as the culture media for the growth of Mucor circinelloides. The results showed that Mucor cells formed pellets during the cell growth, which facilitates the cell harvest from dilute solution. The results also showed that the inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), and acetic acid could be avoided if their concentration was low. In fact, all these by-products may be assimilated as carbon sources for the fungal growth. The results proved the feasibility to reuse the cultural broth water for acid pretreatment and then use for subsequent cell cultivation. The results will have a direct impact on the overall water usage of the process.

Studies on antimicrobial activity, in vitro, of Physalis angulata L. (Solanaceae) fraction and physalin B bringing out the importance of assay determination.

PubMed

Silva, Melissa T G; Simas, Sonia M; Batista, Terezinha G F M; Cardarelli, Paola; Tomassini, Therezinha C B

2005-11-01

Complex physalin metabolites present in the capsules of the fruit of Physalis angulata L. have been isolated and submitted to a series of assays of antimicrobial activity against Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, S. aureus ATCC 25923, S. aureus ATCC 6538P, Neisseria gonorrhoeae ATCC 49226, Escherichia coli ATCC 8739; E. coli ATCC 25922, Candida albicans ATCC 10231 applying different methodologies such as: bioautography, dilution broth, dilution agar, and agar diffusion techniques. A mixture of physalins (pool) containing physalins B, D, F, G inhibit S. aureus ATCC 29213, S. aureus ATCC 25923, S. aureus ATCC 6538P, and N. gonorrhoeae ATCC 49226 at a concentration of 200 mg/microl, using agar dilution assays. The mixture was inactive against P. aeruginosa ATCC27853, E. coli ATCC 8739; E. coli ATCC 25922, C. albicans ATCC 10231 when applying bioautography assays. Physalin B (200 microg/ml) by the agar diffusion assay inhibited S. aureus ATCC 6538P by +/- 85%; and may be considered responsible for the antimicrobial activity.

In Vitro Comparison of Terbinafine and Itraconazole against Penicillium marneffei

PubMed Central

McGinnis, Michael R.; Nordoff, Nicole G.; Ryder, Neil S.; Nunn, Gary B.

2000-01-01

We evaluated terbinafine and itraconazole against 30 isolates of Penicillium marneffei using a modification of the National Committee for Clinical Laboratory Standards broth macrodilution MIC testing protocol for yeasts. The minimal fungicidal concentration (MFC) was determined by plating 100 μl from each MIC drug dilution having no growth onto Sabouraud glucose agar incubated at 30°C. The MFC was the dilution at which growth was absent at 72 h of incubation. The MICs, in micrograms per milliliter, were as follows: terbinafine, 0.03 to 1.0 (geometric mean titer, 0.09); itraconazole, 0.03 to 0.5 (geometric mean titer, 0.04). The MFCs, in micrograms per milliliter, were as follows: terbinafine, 0.03 to 8 (geometric mean titer, 2.60); itraconazole, 0.03 to 8 (geometric mean titer, 2.45). Primary fungicidal activity (MFC within 2 dilutions of MIC) was observed with terbinafine in eight isolates and with itraconazole in four isolates. The data indicate that terbinafine is active against P. marneffei in vitro and may have a previously unrealized role in the management of infections caused by this fungus. PMID:10770792

Comparative performance of isolation methods using Preston broth, Bolton broth and their modifications for the detection of Campylobacter spp. from naturally contaminated fresh and frozen raw poultry meat.

PubMed

Seliwiorstow, T; De Zutter, L; Houf, K; Botteldoorn, N; Baré, J; Van Damme, I

2016-10-03

The performance of different isolation methods was evaluated for the detection of Campylobacter from naturally contaminated raw poultry meat. Therefore, fresh and frozen poultry meat samples were analysed using the standard procedure (ISO 10272-1:2006), enrichment in Preston broth, and enrichment in modified Bolton broth (supplemented with (i) potassium clavulanate (C-BB), (ii) triclosan (T-BB), (iii) polymyxin B (P-BB)). The enrichment cultures were streaked onto both modified charcoal cefoperazone deoxycholate agar (mCCDA) and RAPID'Campylobacter agar (RCA). Moreover, direct plating on mCCDA and RCA was performed to quantify Campylobacter. In total, 33 out of 59 fresh retail meat samples (55.9%) were Campylobacter positive. For both fresh and frozen poultry meat samples, enrichment in Bolton broth (ISO 10272-1:2006) resulted in a higher number of positive samples than enrichment in Preston broth. Supplementation of Bolton broth with potassium clavulanate (C-BB) and triclosan (T-BB) enhanced the Campylobacter recovery from fresh poultry meat compared to non-supplemented Bolton broth, although the use of C-BB was less applicable than T-BB for Campylobacter recovery from frozen samples. Additionally, the use of RCA resulted in a higher isolation rate compared to mCCDA. The present study demonstrates the impact of culture medium on the recovery of Campylobacter from fresh and frozen naturally contaminated poultry meat samples and can support laboratories in choosing the most appropriate culturing method to detect Campylobacter. Copyright © 2016 Elsevier B.V. All rights reserved.

A microbiological method for determining serum levels of broad spectrum β-lactam antibiotics in critically ill patients.

PubMed

Fridlund, Jimmy; Woksepp, Hanna; Schön, Thomas

2016-10-01

Recent studies show that suboptimal blood levels of β-lactam antibiotics are present in intensive care unit (ICU) patients. A common reference method for assessing drug concentrations is liquid chromatography coupled with mass-spectrometry (LC-MS) which is highly accurate but rarely available outside reference centres. Thus, our aim was to develop a microbiological method for monitoring β-lactam antibiotic serum levels which could be used at any hospital with a microbiological laboratory. The method was developed as a 96-well broth microdilution format to assess the concentrations of cefotaxime (CTX), meropenem (MER), and piperacillin (PIP). Patient serum containing antibiotics were diluted in suspensions of bacteria with known minimal inhibitory concentrations (MICs). Serum antibiotic concentrations were calculated by dividing the MIC with the dilution factor at which the serum inhibited growth of the bacterial suspension. Serum (n=88) from ICU patients at four hospitals in south-east Sweden were analysed and compared to LC-MS analysis. The overall accuracy and precision for spiked samples and patient samples was within the pre-set target of ±20.0% for all drugs. There was a significant correlation between the microbiological assay and LC-MS for the patient samples (CTX: r=0.86, n=31; MER: r=0.96, n=11; PIP: r=0.88, n=39) and the agreement around the clinical cut-off for CTX (4.0mg/l), MER (2.0mg/l) and PIP (16.0mg/l) was 90%, 100% and 87%, respectively. The microbiological method has a performance for determination of serum levels of meropenem, piperacillin and cefotaxime suitable for clinical use. It is an inexpensive method applicable in any microbiology laboratory. Copyright © 2016 Elsevier B.V. All rights reserved.

Validation of FMTV Modular VHP/mVHP System and Fumigation Decontamination Process in a C-141B Starlifter Aircraft

DTIC Science & Technology

2007-08-01

each location was aseptically transferred to 5 mL Tryptic Soy Broth (TSB) and incubated at 55 ’C. Coupons were observed the following day. If...Samples were then serially diluted in buffered peptone water and pour plated (1 mL per plate) using Tryptic Soy Agar (TSA). Plates were gently swirled in...1260 area. aft surface inside of hydraulic oil box 19 39 Starboard - 750. 59 On V2 79 On platform, 99 Aft, overhead in on oxygen box overhead, forward

Liquid and vapour-phase antifungal activities of selected essential oils against candida albicans: microscopic observations and chemical characterization of cymbopogon citratus

PubMed Central

2010-01-01

Background Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil. Methods Minimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS. Results Lemon grass (Cymbopogon citratus) essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita) and eucalyptus (Eucalyptus globulus) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%). Conclusion Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious morphological changes in cellular structures and cell surface alterations. PMID:21067604

Nanoemulsion of orange oil with non ionic surfactant produced emulsion using ultrasonication technique: evaluating against food spoilage yeast

NASA Astrophysics Data System (ADS)

Sugumar, Saranya; Singh, Sanjay; Mukherjee, Amitava; Chandrasekaran, N.

2016-01-01

In recent years, food industries have shown great interest in developing nanoemulsion (NE) using essential oils (EOs) to prevent food spoilage caused by microorganisms. The hydrophobic properties of EOs have lead to reduced solubilization effect of food, which in turn, created a negative impact on the quality of food and its antimicrobial efficacy. Focusing this issue, we attempted a unique NE preparation using orange oil, Tween 80 (organic phase) and water (aqueous phase) by sonication technique. Based on thermodynamic stability studies, the effective diameter was reported to be in the size range from 20 to 30 nm. Saccharomyces cerevisiae was used in testing the anti-yeast effect. Their activity was studied in both growth medium and apple juice. The minimum inhibitory concentration of this NE was determined using broth dilution method. At 2 μl/ml, orange oil NE demonstrated inhibition of tested microorganisms. The kinetics of killing curve, have shown that the NE treated cells had lost its viability within 30 min of interaction. Also, SEM image revealed that the treated cells became distorted in comparison to their control cells. NE treated apple juice showed complete loss of viability even on dilution as compared to their controls.

Antibacterial activity of Citrus limonum fruit juice extract.

PubMed

Okeke, Malachy Ifeanyi; Okoli, Arinze Stanley; Eze, Edith Nneka; Ekwume, Grace Chinwe; Okosa, Evangelin Uchena; Iroegbu, Christian Ukwuoma

2015-09-01

The fruit juice extract of Citrus limonum was investigated for antibacterial activity. The antibacterial activity of the extract on ten strains of bacteria was determined by both agar well diffusion and macro-broth dilution methods. The extract was variously bacteriostatic and bactericidal against Bacillussubtilis ATCC 6051, Staphylococcus aureus ATCC 12600, Escherichia coli ATCC 11775, Pseudomonas aeruginosa ATCC 10145 as well as locally isolated clinical strains of the above bacteria and Salmonella kintambo (Human: 13, 23: mt:-), Salmonella typhi and Proteus sp. The MICs ranged from 0.78 mg/ml to 50mg/ml; MBCs, 25.0mg/ml to >100mg/ml and MBC/MIC ratios 2.0 to >16.0. These results provide scientific justification for the medicinal use of Citrus limonum fruit juice by Nigerian herbalists in the treatment of diseases in which strains of the test organisms have been implicated as etiologic agents.

In Vitro Activity of Cephalothin and Three Penicillins Against Escherichia coli and Proteus Species

PubMed Central

Barry, Arthur L.; Hoeprich, Paul D.

1973-01-01

The susceptibility of clinical isolates of Escherichia coli (67) and Proteus species (58) to cephalothin, ampicillin, benzyl penicillin, and phenoxymethyl penicillin was determined in vitro by using broth dilution and disk diffusion tests. The data were correlated by using a four-category scheme for interpreting minimal inhibitory concentrations (groups 1 to 4) as recommended by a subcommittee of an international collaborative study of susceptibility testing. With cephalothin and ampicillin, groups 1 (susceptible) and 2 (moderately susceptible) were susceptible by the disk test, and with benzyl penicillin, similar results were observed when the interpretive zone standards were changed. Strains categorized as group 4 (very resistant) were resistant by the disk method, but group 3 (moderately resistant) strains were not adequately distinguished by disk testing. Group 3 susceptibility to benzyl and phenoxymethyl penicillins can be predicted by extrapolating results from tests with ampicillin disks. PMID:4202343

A new antibacterial benzophenone glycoside from Psidium guajava (Linn.) leaves.

PubMed

Ukwueze, Stanley E; Osadebe, Patience O; Okoye, Festus B C

2015-01-01

Bioactivity-guided fractionation of methanol extract from the leaves of Psidium guajava L. (Myrtaceae) yielded a new benzophenone glycoside, Guajaphenone A (2) together with two known compounds, Garcimangosone D (1) and Guaijaverin (3). Their structures were elucidated by analysis of spectroscopic data including 1D and 2D NMR and electrospray ionisation mass spectrometry (ESI-MS). The isolated compounds were screened against standard strains of Gram-positive and Gram-negative bacteria using broth dilution assay method, and the MIC values determined and compared with reference antibiotic ceftriaxone. They were found to have significant antibacterial activities against Escherichia coli and Staphylococcus aureus with all of them showing better activities against S. aureus, but displaying weaker activities, in comparison to ceftriaxone. However, despite reduced effect of these compounds against the organisms, this work opens the perspective to use these molecules as 'leads' for the design of novel and selective drug candidates for some tropical infectious diseases.

Chemical composition and antibacterial activity of Lavandula coronopifolia essential oil against antibiotic-resistant bacteria.

PubMed

Ait Said, L; Zahlane, K; Ghalbane, I; El Messoussi, S; Romane, A; Cavaleiro, C; Salgueiro, L

2015-01-01

The aim of this study was to analyse the composition of the essential oil (EO) of Lavandula coronopifolia from Morocco and to evaluate its in vitro antibacterial activity against antibiotic-resistant bacteria isolated from clinical infections. The antimicrobial activity was assessed by a broth micro-well dilution method using multiresistant clinical isolates of 11 pathogenic bacteria: Klebsiella pneumoniae subsp. pneumoniae, Klebsiella ornithinolytica, Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Providencia rettgeri, Citrobacter freundii, Hafnia alvei, Salmonella spp., Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus. The main compounds of the oil were carvacrol (48.9%), E-caryophyllene (10.8%) and caryophyllene oxide (7.7%). The oil showed activity against all tested strains with minimal inhibitory concentration (MIC) values ranging between 1% and 4%. For most of the strains, the MIC value was equivalent to the minimal bactericidal concentration value, indicating a clear bactericidal effect of L. coronopifolia EO.

In vitro activity of flomoxef against rapidly growing mycobacteria.

PubMed

Tsai, Moan-Shane; Tang, Ya-Fen; Eng, Hock-Liew

2008-06-01

The aim of this study was to determine the in vitro sensitivity of rapidly growing mycobacteria (RGM) to flomoxef in respiratory secretions collected from 61 consecutive inpatients and outpatients at Chang Gung Memorial Hospital-Kaohsiung medical center between July and December, 2005. Minimal inhibitory concentrations (MIC) of flomoxef were determined by the broth dilution method for the 61 clinical isolates of RGMs. The MICs of flomoxef at which 90% of clinical isolates were inhibited was >128 microg/mL in 26 isolates of Mycobacterium abscessus and 4 microg/mL in 31 isolates of M. fortuitum. Three out of 4 clinical M. peregrinum isolates were inhibited by flomoxef at concentrations of 4 microg/mL or less. Although the numbers of the clinical isolates of RGMs were small, these preliminary in vitro results demonstrate the potential activity of flomoxef in the management of infections due to M. fortuitum, and probably M. peregrinum in humans.

Multidrug resistant bacteria are sensitive to Euphorbia prostrata and six others Cameroonian medicinal plants extracts.

PubMed

Voukeng, Igor K; Beng, Veronique P; Kuete, Victor

2017-07-25

Multidrug resistant (MDR) bacteria are responsible for therapeutic failure and there is an urgent need for novels compounds efficient on them. Eleven methanol extracts from seven Cameroonian medicinal plants were tested for their antibacterial activity using broth micro-dilution method against 36 MDR bacterial strains including Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella pneumoniae, Providencia stuartii, Pseudomonas aeruginosa and Staphylococcus aureus. Euphorbia prostrata extract was found active against all the 36 tested bacteria including Gram-negative phenotypes over-expressing efflux pumps such as P. aeruginosa PA124, E. aerogenes CM64 and E. coli AG102. E. prostrata had minimal inhibitory concentrations values between 128 and 256 µg/mL on 55.55% of the studied microorganisms. Other plants extract displayed selective antibacterial activity. Results obtained in this study highlight the antibacterial potential of the tested plants and the possible use of E. prostrata to combat bacterial infections including MDR phenotypes.

Adherence to stainless steel by foodborne microorganisms during growth in model food systems.

PubMed

Hood, S K; Zottola, E A

1997-07-22

Biofilm formation on stainless steel by Salmonella typhimurium, Listeria monocytogenes, Escherichia coli O157:H7, Pseudomonas fragi and Pseudomonas fluorescens during growth in model food systems was studied. Test growth media included tryptic soy broth (TSB), diluted TSB (dTSB), 1% reconstituted skim milk (RSM) and diluted meat juice (DMJ). Adherent cells were stained with acridine orange and enumerated using epifluorescent microscopy and computerized image analysis. Cells were observed on the stainless steel surface after 1 h in all of the media. However, the increases in the number of adherent cells over time was seen only with S. typhimurium in DMJ, E. coli O157:H7 in TSB, dTSB and DMJ, P. fragi in RSM and P. fluorescens in RSM. The medium which produced the highest observed level of adherent cells was different for each microorganism.

Adsorption of water and butanol in silicalite-1 film studied with in situ attenuated total reflectance-Fourier transform infrared spectroscopy.

PubMed

Farzaneh, Amirfarrokh; Zhou, Ming; Potapova, Elisaveta; Bacsik, Zoltán; Ohlin, Lindsay; Holmgren, Allan; Hedlund, Jonas; Grahn, Mattias

2015-05-05

Biobutanol produced by, e.g., acetone-butanol-ethanol (ABE) fermentation is a promising alternative to petroleum-based chemicals as, e.g., solvent and fuel. Recovery of butanol from dilute fermentation broths by hydrophobic membranes and adsorbents has been identified as a promising route. In this work, the adsorption of water and butanol vapor in a silicalite-1 film was studied using in situ attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy to better understand the adsorption properties of silicalite-1 membranes and adsorbents. Single-component adsorption isotherms were determined in the temperature range of 35-120 °C, and the Langmuir model was successfully fitted to the experimental data. The adsorption of butanol is very favorable compared to that of water. When the silicalite-1 film was exposed to a butanol/water vapor mixture with 15 mol % butanol (which is the vapor composition of an aqueous solution containing 2 wt % butanol, a typical concentration in an ABE fermentation broth, i.e., the composition of the gas obtained from gas stripping of an ABE broth) at 35 °C, the adsorption selectivity toward butanol was as high as 107. These results confirm that silicalite-1 quite selectively adsorbs hydrocarbons from vapor mixtures. To the best of our knowledge, this is the first comprehensive study on the adsorption of water and butanol in silicalite-1 from vapor phase.

Antianaerobic Antimicrobials: Spectrum and Susceptibility Testing

PubMed Central

Wexler, Hannah M.; Goldstein, Ellie J. C.

2013-01-01

SUMMARY Susceptibility testing of anaerobic bacteria recovered from selected cases can influence the choice of antimicrobial therapy. The Clinical and Laboratory Standards Institute (CLSI) has standardized many laboratory procedures, including anaerobic susceptibility testing (AST), and has published documents for AST. The standardization of testing methods by the CLSI allows comparisons of resistance trends among various laboratories. Susceptibility testing should be performed on organisms recovered from sterile body sites, those that are isolated in pure culture, or those that are clinically important and have variable or unique susceptibility patterns. Organisms that should be considered for individual isolate testing include highly virulent pathogens for which susceptibility cannot be predicted, such as Bacteroides, Prevotella, Fusobacterium, and Clostridium spp.; Bilophila wadsworthia; and Sutterella wadsworthensis. This review describes the current methods for AST in research and reference laboratories. These methods include the use of agar dilution, broth microdilution, Etest, and the spiral gradient endpoint system. The antimicrobials potentially effective against anaerobic bacteria include beta-lactams, combinations of beta-lactams and beta-lactamase inhibitors, metronidazole, chloramphenicol, clindamycin, macrolides, tetracyclines, and fluoroquinolones. The spectrum of efficacy, antimicrobial resistance mechanisms, and resistance patterns against these agents are described. PMID:23824372

Comparison between Bactec Peds Plus F Broth and Conventional Medium for Vitreous Culture.

PubMed

Tabatabaei, Seyed Ali; Tabatabaei, Seyed Mehdi; Soleimani, Mohammad; Hejrati, Bahman; Mirshahi, Ahmad; Khadabandeh, Alireza; Ahmadraji, Aliasghar; Valipour, Niloofar

2018-05-10

To evaluate the yield of Bactec Peds Plus F broth for vitreous sample culture in cases with infectious endophthalmitis in comparison to conventional medium. Consecutive cases of clinically suspected endophthalmitis were prospectively enrolled in this study. Cultures of the vitreous sample were performed in both Bactec Peds Plus F broth and conventional mediums. Forty eyes of 40 patients who were clinically suspected of infectious endophthalmitis with different etiologies were enrolled in this study. The positive culture yield was 50% and 35% in Bactec Peds Plus F broth and conventional mediums, respectively (p = 0.07). The result of Bactec group was not significantly different among patients who had a history of intravitreal antibiotic injection (p > 0.05) (Table 2). However, results of the conventional method were significantly negative in the previous intravitreal antibiotic injection group (p = 0.02). There was no correlation between the methods of vitreous sampling in both culture methods. Although the difference between two culture methods was not statistically significant in this study, Bactec Peds Plus F broth showed higher positive culture yield in patients with a history of intravitreal antibiotic injection.

Comparative antimicrobial characterization of LBM415 (NVP PDF-713), a new peptide deformylase inhibitor of clinical importance.

PubMed

Fritsche, Thomas R; Sader, Helio S; Cleeland, Roy; Jones, Ronald N

2005-04-01

LBM415 (NVP PDF-713) is the first member of the peptide deformylase (PDF) inhibitor class being developed for clinical trials as a parenteral and oral agent for treatment of community-acquired respiratory tract disease and serious infections caused by antimicrobial-resistant gram-positive cocci. In this study susceptibility testing results from 1,306 recent clinical isolates selected to over-represent resistance trends among the species were summarized. All staphylococci (153 strains; MIC at which 90% of isolates were inhibited [MIC90], 2 microg/ml), Streptococcus pneumoniae (170 strains; MIC90, 1 microg/ml), other streptococci (150 strains; MIC90, 1 microg/ml), enterococci (104 strains; MIC90, 4 microg/ml), Moraxella catarrhalis (103 strains; MIC90, 0.5 microg/ml), and Legionella pneumophila (50 strains; MIC90, 0.12 microg/ml) were inhibited at < or = 8 microg of LBM415/ml, as were 97% of Haemophilus influenzae isolates (300 strains; MIC90, 4 to 8 microg/ml). Among other bacterial groups, 100% of gram-positive and -negative anaerobes, including 22 Bacteroides spp. strains (31 strains total; MIC90, 1 microg/ml), were inhibited by < or = 4 microg/ml, whereas Enterobacteriaceae (112 strains) and most nonfermentative bacilli (107 strains) were not inhibited at readily achievable concentrations. The compound was found to have a dominantly bacteriostatic action, and spontaneous single-step mutational rates occurred at low levels (10(-6) to <10(-8)). Drug interaction studies failed to identify any class-specific synergistic interactions, nor were antagonistic interactions observed. Variations in broth and agar MIC test conditions demonstrated that, whereas the agar-based method trended towards a 1-log2 dilution-higher MIC than the broth method and was inoculum dependent, other variations in incubation environment, medium supplements, pH, or calcium concentration had little influence on LBM415 MIC results. Use of the efflux inhibitor phe-arg-beta-naphthylamide showed an average of 1 log2 dilution decrease in H. influenzae MICs, demonstrating the contribution of efflux pumps in influencing susceptibility to PDF inhibitors. The in vitro activity of LBM415 against targeted bacterial species, including resistant subsets, and other laboratory characteristics of this novel compound demonstrate the potential of PDF inhibitors as a new class of antimicrobial agents.

A new effective assay to detect antimicrobial activity of filamentous fungi.

PubMed

Pereira, Eric; Santos, Ana; Reis, Francisca; Tavares, Rui M; Baptista, Paula; Lino-Neto, Teresa; Almeida-Aguiar, Cristina

2013-01-15

The search for new antimicrobial compounds and the optimization of production methods turn the use of antimicrobial susceptibility tests a routine. The most frequently used methods are based on agar diffusion assays or on dilution in agar or broth. For filamentous fungi, the most common antimicrobial activity detection methods comprise the co-culture of two filamentous fungal strains or the use of fungal extracts to test against single-cell microorganisms. Here we report a rapid, effective and reproducible assay to detect fungal antimicrobial activity against single-cell microorganisms. This method allows an easy way of performing a fast antimicrobial screening of actively growing fungi directly against yeast. Because it makes use of an actively growing mycelium, this bioassay also provides a way for studying the production dynamics of antimicrobial compounds by filamentous fungi. The proposed assay is less time consuming and introduces the innovation of allowing the direct detection of fungal antimicrobial properties against single cell microorganisms without the prior isolation of the active substance(s). This is particularly useful when performing large screenings for fungal antimicrobial activity. With this bioassay, antimicrobial activity of Hypholoma fasciculare against yeast species was observed for the first time. Copyright © 2012 Elsevier GmbH. All rights reserved.

Rapid detection of Salmonella in milk by electrochemical magneto-immunosensing.

PubMed

Liébana, Susana; Lermo, Anabel; Campoy, Susana; Cortés, María Pilar; Alegret, Salvador; Pividori, María Isabel

2009-10-15

A very simple and rapid method for the detection of Salmonella in milk is reported. In this approach, the bacteria are captured and preconcentrated from milk samples with magnetic beads through an immunological reaction. A second polyclonal antibody labeled with peroxidase is used as serological confirmation with electrochemical detection based on a magneto-electrode. The 'IMS/m-GEC electrochemical immunosensing' approach shows a limit of detection of 5 x 10(3) and 7.5 x 10(3)CFU mL(-1) in LB and in milk diluted 1/10 in LB broth, respectively, in 50 min without any pretreatment. If the skimmed-milk is preenriched for 6h, the method is able to detect as low as 1.4 CFU mL(-1), while if it is preenriched for 8h, as low as 0.108 x CFU mL(-1) (2.7 x CFU in 25 g of milk, in 5 samples of 5 mL) are detected accordingly with the legislation. Moreover, the method is able to clearly distinguish between food pathogenic bacteria such as Salmonella and Escherichia coli. The features of this approach are discussed and compared with classical culture methods.

In vitro drug susceptibility pattern of Mycoplasma alligatoris isolated from symptomatic American alligators (Alligator mississippiensis).

PubMed

Helmick, Kelly E; Brown, Daniel R; Jacobson, Elliott R; Brown, Mary B

2002-06-01

A recently described mycoplasma, Mycoplasma alligatoris, was isolated from dead American alligators (Alligator mississippiensis) that had demonstrated clinical signs of lethargy, anorexia, bilateral ocular discharge, edema. paraparesis, and polyarthritis. The in vitro minimum inhibitory concentration for nine antibacterial agents was determined through serial dilution in broth and plate culture for M. alligatoris isolates. The inhibitory concentration obtained for doxycycline, enrofloxacin, sarafloxacin, oxytetracycline, tilmicosin, and tylosin (< 1 microg/ml) was lower than that of clindamycin (1-8 microg/ml), chloramphenicol (8-16 microg/ml), and erythromycin (32-138 microg/ml).

The in vitro antifungal activity of ketoconazole, zinc pyrithione, and selenium sulfide against Pityrosporum and their efficacy as a shampoo in the treatment of experimental pityrosporosis in guinea pigs.

PubMed

Van Cutsem, J; Van Gerven, F; Fransen, J; Schrooten, P; Janssen, P A

1990-06-01

The fungistatic and fungicidal activity of ketoconazole, zinc pyrithione, and selenium sulfide against Pityrosporum, a yeast thought to play a pathogenic role in seborrheic dermatitis and dandruff, was assessed in Dixon broth for Pityrosporum ovale and Sabouraud broth for Pityrosporum pachydermatis. Ketoconazole inhibited growth at concentrations ranging from 0.001 to 1 micrograms/ml. For zinc pyrithione and selenium sulfide higher concentrations were needed. In a guinea pig model the efficacy of treatment with four shampoos (Nizoral [Jansen], EDS Zinc [Schering], Zinkan [Lederle], and Selsun [Abbott]) was compared. The animals were inoculated for 7 consecutive days on intact skin. The lesions were scored for erythema, folliculitis, and hyperkeratosis 24 hours after the last inoculation and after treatment. Final evaluations were made 13 days after infection (10 days after last shampoo application). Treatment with undiluted and diluted (1:10) shampoos showed consistently superior clinical and mycologic results for Nizoral shampoo. None of the shampoos produced side effects.

Ultrafiltration of hemicellulose hydrolysate fermentation broth

NASA Astrophysics Data System (ADS)

Kresnowati, M. T. A. P.; Desiriani, Ria; Wenten, I. G.

2017-03-01

Hemicelulosic material is often used as the main substrate to obtain high-value products such as xylose. The five carbon sugar, xylose, could be further processed by fermentation to produce xylitol. However, not only the hemicellulose hydrolysate fermentation broth contains xylitol, but also metabolite products, residual substances, biomass and mineral salts. Therefore, in order to obtain the end products, various separation processes are required to separate and purify the desired product from the fermentation broth. One of the most promising downstream processing methods of fermentation broth clarification is ultrafiltration due to its potential for energy saving and higher purity. In addition, ultrafiltration membrane has a high performance in separating inhibitory components in the fermentation broth. This paper assesses the influence of operating conditions; including trans-membrane pressure, velocity, pH of the fermentation broth solutions, and also to the xylitol concentration in the product. The challenges of the ultrafiltration process will be pointed out.

In vitro susceptibility of filamentous fungi to itraconazole, voriconazole and posaconazole by Clinical and Laboratory Standards Institute reference method and E-test.

PubMed

Kondori, N; Svensson, E; Mattsby-Baltzer, I

2011-09-01

The use of anti-fungal agents has increased dramatically in recent years and new drugs have been developed. Several methods are available for determinations of their specific biological activities, i.e. the standard method for minimum inhibitory concentration-determination is described in M-38 [Clinical and Laboratory Standards Institute document M-38 (CLSI M-38)]. However, alternative methods, such as the E-test, are currently available in Mycology laboratories. The susceptibilities of clinical isolates of Aspergillus spp. (n = 29), Fusarium spp. (n = 5), zygomycetes (n = 21) and Schizophyllum (n = 1) were determined for itraconazole, voriconazole and posaconazole, using the CLSI M-38-A broth dilution method and also by the E-test. A good overall agreement (83.7%) between the two methods for all drugs and organisms was observed. Analyses of voriconazole showed a better agreement (93%) between the methods than posaconazole and itraconazole (85% and 74% respectively). Aspergillus spp. were the most susceptible fungi to the anti-fungal agents tested in this study. Posaconazole was the most active drug against filamentous fungi in vitro, followed by itraconazole and voriconazole. The latter (voriconazole) demonstrated no significant in vitro activity against zygomycetes. © 2010 Blackwell Verlag GmbH.

Synthesis and Evaluation of Ester Derivatives of 10-Hydroxycanthin-6-one as Potential Antimicrobial Agents.

PubMed

Zhao, Fei; Dai, Jiang-Kun; Liu, Dan; Wang, Shi-Jun; Wang, Jun-Ru

2016-03-21

As part of our continuing research on canthin-6-one antimicrobial agents, a new series of ester derivatives of 10-hydroxycanthin-6-one were synthesized using a simple and effective synthetic route. The structure of each compound was characterized by NMR, ESI-MS, FT-IR, UV, and elemental analysis. The antimicrobial activity of these compounds against three phytopathogenic fungi (Alternaria solani, Fusarium graminearum, and Fusarium solani) and four bacteria (Bacillus cereus, Bacillus subtilis, Ralstonia solanacearum, and Pseudomonas syringae) were evaluated using the mycelium linear growth rate method and micro-broth dilution method, respectively. The structure-activity relationship is discussed. Of the tested compounds, 4 and 7s displayed significant antifungal activity against F. graminearum, with inhibition rates of 100% at a concentration of 50 μg/mL. Compounds 5, 7s, and 7t showed the best inhibitory activity against all the tested bacteria, with minimum inhibitory concentrations (MICs) between 3.91 and 31.25 μg/mL. Thus, 7s emerged as a promising lead compound for the development of novel canthine-6-one antimicrobial agents.

Antimicrobial activity of some essential oils against oral multidrug-resistant Enterococcus faecalis in both planktonic and biofilm state

PubMed Central

Benbelaïd, Fethi; Khadir, Abdelmounaïm; Abdoune, Mohamed Amine; Bendahou, Mourad; Muselli, Alain; Costa, Jean

2014-01-01

Objective To evaluate some essential oils in treatment of intractable oral infections, principally caused by biofilm of multidrug-resistant Enterococcus faecalis (E. faecalis), such as persistent endodontic infections in which their treatment exhibits a real challenge for dentists. Methods Ten chemically analyzed essential oils by gas chromatography-mass spectrometry were evaluated for antimicrobial activity against sensitive and resistant clinical strains of E. faecalis in both planktonic and biofilm state using two methods, disk diffusion and broth micro-dilution. Results Studied essential oils showed a good antimicrobial activity and high ability in E. faecalis biofilm eradication, whether for sensitive or multidrug-resistant strains, especially those of Origanum glandulosum and Thymbra capitata with interesting minimum inhibitory concentration, biofilm inhibitory concentration, and biofilm eradication concentration values which doesn't exceed 0.063%, 0.75%, and 1.5%, respectively. Conclusions Findings of this study indicate that essential oils extracted from aromatic plants can be used in treatment of intractable oral infections, especially caused by biofilm of multidrug-resistant E. faecalis. PMID:25182948

In vitro anti-acne activity of phytoactives from the stem bark of Artocarpus hirsutus Lam. and characterisation of pyranocycloartobiloxanthone A as a mixture of two anomers.

PubMed

Nayak, Mahadeva; Nagarajan, A; Majeed, Muhammed; Nagabhushanam, Kalyanam; Choudhury, Ambar K

2017-08-18

This study is aimed to isolate the phytoactives from the stem bark of Artocarpus hirsutus and evaluate their in vitro anti-acne activity. The ethanolic stem bark extract of A. hirsutus provided two major phytoactive constituents: (i) pyranocycloartobiloxanthone A, (1) and (ii) Artonine E, (2) whose structures were determined by NMR and MS spectroscopic analysis. The present study is the first to report compound 1 as a mixture of two anomers (α and β), approximately 70:30 ratio. Both compounds 1 and 2 were isolated for the first time from this plant. In vitro anti-acne activity of compounds 1 and 2 were evaluated by agar well diffusion method and the minimum inhibition was determined by broth micro dilution method. The result of anti-microbial activity (MIC = 2.0 μg/mL each) is comparable to antibiotic, Clindamycin (MIC = 0.03 μg/mL) and clearly demonstrate their potential as anti-acne agents.

In vitro antimicrobial activity of extracts and isolated compound from Dalbergia stipulacea Roxb. leaves

NASA Astrophysics Data System (ADS)

Kumar, Arvind; Bhat, Tahir Ahmad; Singh, Rattan Deep

2017-07-01

The study was designed to examine the in vitro antimicrobial efficacy of extracts and isolated compound of Dalbergia stipulacea. Combined extracts (chloroform and methanol) of plant leaves fractionated with n-butanol loaded with column afforded a flavonoid glycoside compound identified as luteolin 4'-rutinoside. Different extracts and isolated compound exhibited pronounced antibacterial and antifungal varied activities against four bacteria (Clostridium acetobutylinium, Bacillus subtilis, Streptococcus mutans, and Pseudomonas sp.) and one fungus (Candida albicans) susceptibility were determined using disc diffusion method. The minimum inhibitory concentration (MIC) of extracts and isolated compounds was determined by broth dilution method. The maximum activity was shown by chloroform extract against C. albicans with a zone of inhibition of 17 mm and minimum activity was displayed by methanolic extract against Pseudomonas sp. with 5 mm. However, isolated compound has shown maximum activity against Pseudomonas sp. with 15 mm. The MIC values higher in methanol extract against Pseudomonas sp. and isolated compound shows good against Pseudomonas sp. and B. subtilis. Our findings indicate that plant could be used as a good antimicrobial agent in food, pharmaceutical and bio-pesticide industries.

The effect of clary sage oil on staphylococci responsible for wound infections

PubMed Central

Głowacka, Anna; Poznańska-Kurowska, Katarzyna; Kaszuba, Andrzej; Urbaniak, Anna; Kowalczyk, Edward

2015-01-01

Introduction The spreading of bacterial antibiotic resistance among clinical strains of pathogenic bacteria has made investigators to search for other active antibacterial agents which could provide a valuable complement to the existing therapies. Aim To determine the antibacterial activity of clary sage oil (Salvia sclarea L.) against Staphylococcus clinical strains which were isolated from patients with wound infections. Material and methods A comprehensive evaluation of Staphylococcus clinical strain resistance to antibiotics was performed. The constituents of clary sage oil were assayed by GC-FID-MS analysis. The minimal inhibitory concentration (MIC) of the tested essential oil against staphylococci by the micro-dilution broth method was determined. Results The clary sage oil was active against Staphylococcus aureus, S. epidermidis and S. xylosus with MIC values ranging from 3.75 to 7.00 µl/ml. Conclusions The results of the in vitro tests encourage to use formulations containing sage oil as the active natural antimicrobial agent. Because of its antimicrobial properties clary sage oil may be applied to treat wounds and skin infections. PMID:25821423

Method for solubilization of low-rank coal using low molecular weight cell-free filtrates derived from cultures of Coriolus versicolor

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

Stewart, D.L.; Fredrickson, J.K.; Campbell, J.A.

1992-01-28

This patent describes a method for isolating an extracellular product derived from a broth of Coriolus versicolor. It comprises separating the cells from a broth of C. versicolor to obtain a cell-free filtrate; separating from the cell-free filtrate a fraction containing molecules of molecular weight in the range of about 500 to 1000 daltons. This patent also describes a method for degrading low-rank coal to a water-soluble material. It comprises contacting the low-rank coal with a cell-free fraction from the broth of Coriolus versicolor containing molecules in the molecular weight range of about 500 to 1000 daltons.

Superparamagnetic poly(methyl methacrylate) beads for nattokinase purification from fermentation broth.

PubMed

Yang, Chengli; Xing, Jianmin; Guan, Yueping; Liu, Huizhou

2006-09-01

An effective method for purification of nattokinase from fermentation broth using magnetic poly(methyl methacrylate) (PMMA) beads immobilized with p-aminobenzamidine was proposed in this study. Firstly, magnetic PMMA beads with a narrow size distribution were prepared by spraying suspension polymerization. Then, they were highly functionalized via transesterification reaction with polyethylene glycol. The surface hydroxyl-modified magnetic beads obtained were further modified with chloroethylamine to transfer the surface amino-modified magnetic functional beads. The morphology and surface functionality of the magnetic beads were examined by scanning electron microscopy and Fourier transform infrared. An affinity ligand, p-aminobenzamidine was covalently immobilized to the amino-modified magnetic beads by the glutaraldehyde method for nattokinase purification directly from the fermentation broth. The purification factor and the recovery of the enzyme activity were found to be 8.7 and 85%, respectively. The purification of nattokinase from fermentation broth by magnetic beads only took 40 min, which shows a very fast purification of nattokinase compared to traditional purification methods.

Antimicrobial activity evaluation and comparison of methods of susceptibility for Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacter spp. isolates.

PubMed

Rechenchoski, Daniele Zendrini; Dambrozio, Angélica Marim Lopes; Vivan, Ana Carolina Polano; Schuroff, Paulo Alfonso; Burgos, Tatiane das Neves; Pelisson, Marsileni; Perugini, Marcia Regina Eches; Vespero, Eliana Carolina

The production of KPC (Klebsiella pneumoniae carbapenemase) is the major mechanism of resistance to carbapenem agents in enterobacterias. In this context, forty KPC-producing Enterobacter spp. clinical isolates were studied. It was evaluated the activity of antimicrobial agents: polymyxin B, tigecycline, ertapenem, imipenem and meropenem, and was performed a comparison of the methodologies used to determine the susceptibility: broth microdilution, Etest ® (bioMérieux), Vitek 2 ® automated system (bioMérieux) and disc diffusion. It was calculated the minimum inhibitory concentration (MIC) for each antimicrobial and polymyxin B showed the lowest concentrations for broth microdilution. Errors also were calculated among the techniques, tigecycline and ertapenem were the antibiotics with the largest and the lower number of discrepancies, respectively. Moreover, Vitek 2 ® automated system was the method most similar compared to the broth microdilution. Therefore, is important to evaluate the performance of new methods in comparison to the reference method, broth microdilution. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Dried-bonito aroma components enhance salivary hemodynamic responses to broth tastes detected by near-infrared spectroscopy.

PubMed

Matsumoto, Tomona; Saito, Kana; Nakamura, Akio; Saito, Tsukasa; Nammoku, Takashi; Ishikawa, Masashi; Mori, Kensaku

2012-01-25

To elucidate the effects of aroma from dried bonito (katsuo-bushi) on broth tastes caused by the central integration of flavor, optical imaging of salivary hemodynamic responses was conducted using near-infrared spectroscopy (NIRS). A reconstituted dried bonito flavored broth produced a significantly larger hemodynamic response than the odorless broth taste solutions for 5 of the 10 panelists, who felt that the combination of the aroma with the tastes was congruent. In the remaining 5 panelists who felt the combination incongruent, the flavored broth did not cause the enhancement of response. Moreover, when the odor-active smoky parts were removed from the flavoring, the reconstituted flavoring did not enhance the response in the former five panelists. These results indicate that NIRS offers a sensitive method to detect the effect of specific congruent aroma components from dried-bonito broth on the taste-related salivary hemodynamic responses, dependent on the perceptual experience of the combination of aromas and tastes.

Evaluation of Antifungal Effect of Silver Nanoparticles Against Microsporum canis, Trichophyton mentagrophytes and Microsporum gypseum

PubMed Central

Ayatollahi Mousavi, Seyyed Amin; Salari, Samira; Hadizadeh, Sanaz

2015-01-01

Background Dermatophytosis is the common cutaneous infections in humans and animals, which is caused by the keratinophylic fungus called dermatophytes. In recent years, drugs resistance in pathogenic fungi, including dermatophyte strains to the current antifungals have been increased. Objectives The aim of this study was to evaluate the antifungal efficacy of AgNPs against Microsporum canis, Trichophyton mentagrophytes , and Microsporum gypseum. Materials and Methods The antifungal susceptibility of nanosilver particles compared with griseofulvin (GR). Its efficacy was investigated against three strains of dermatophytes by both agar dilution and broth microdilution test (BMD). Results The average minimum inhibitory concentration (MIC) AgNPs on M. canis, T. mentagrophytes and M. gypseum were 200, 180 and 170 μg.mL-1, respectively. Whereas these strains showed MIC of 25, 100 and 50 μg.mL-1 for GR. Conclusions Our finding indicated that the AgNPs was less active than GR but it had anti-dermatophytic effect. PMID:28959308

Screening of antibacterial effects of anise essential oil alone and in combination with conventional antibiotics against Streptococcus pneumoniae clinical isolates.

PubMed

Gradinaru, Adina Catinca; Miron, Anca; Trifan, Adriana; Spac, A; Brebu, M; Aprotosoaie, Ana Clara

2014-01-01

This study aimed to investigate the effects of anise essential oil alone and in combination with conventional antibiotics (amoxicillin, ciprofloxacin) against Streptococcus pneumoniae clinical isolates. MATERIAL AND METHODs: Anise essential oil (AEO) was isolated by hydrodistillation from dried powdered fruits. Its chemical composition was investigated by GC-MS and GC-FID. Broth dilution assay was used to evaluate the antibacterial effects of anise essential oil. The interactions with antibiotics were studied by the checkerboard assay. Trans-anethole (90.18%) was identified as major constituent in anise essential oil. Almost all combinations AEO-amoxicillin and AEO-ciprofloxacin showed indifferent interactions (1 < FIC index < or = 2). Positive interactions (addition and weak synergism) were found only for four combinations AEO-amoxicillin (FIC index = 1,0.62, 0.75 and 0.5) and one combination AEO-ciprofloxacin (FIC index = 0.62). Herbal products containing anise essential oil may be used as expectorants in combination with amoxicillin or ciprofloxacin in Streptococcus pneumoniae infections without diminishing antibiotic efficacy.

Antibacterial activity and morphological changes of Pseudomonas aeruginosa cells after exposure to Vernonia cinerea extract.

PubMed

Latha, Lachimanan Yoga; Darah, Ibrahim; Kassim, Mohd Jain Noordin Mohd; Sasidharan, Sreenivasan

2010-08-01

The antibacterial activity of Vernonia cinerea (L.) extract was investigated using the broth dilution method. The extract showed a favorable antimicrobial activity against Pseudomonas aeruginosa with a minimum inhibition concentration (MIC) value of 3.13 mg/mL. V. cinerea extract at (1/2), 1, or 2 times the MIC significantly inhibited bacterial growth with a noticeable drop in optical density (OD) of the bacterial culture, thus confirming the antibacterial activity of the extract on P. aeruginosa. Imaging using scanning (SEM) and transmission (TEM) electron microscopy was done to determine the major alterations in the microstructure of the extract-treated P. aeruginosa. The main abnormalities noted via SEM and TEM studies were the alteration in morphology of the bacterial cells. The main reason for this destruction was the severe alterations of the cell wall with the formation of holes, invaginations, and morphological disorganization caused by the extract. The authors conclude that the extract may be used as a candidate for the development of antimicrobial agents.

The effect of clary sage oil on staphylococci responsible for wound infections.

PubMed

Sienkiewicz, Monika; Głowacka, Anna; Poznańska-Kurowska, Katarzyna; Kaszuba, Andrzej; Urbaniak, Anna; Kowalczyk, Edward

2015-02-01

The spreading of bacterial antibiotic resistance among clinical strains of pathogenic bacteria has made investigators to search for other active antibacterial agents which could provide a valuable complement to the existing therapies. To determine the antibacterial activity of clary sage oil (Salvia sclarea L.) against Staphylococcus clinical strains which were isolated from patients with wound infections. A comprehensive evaluation of Staphylococcus clinical strain resistance to antibiotics was performed. The constituents of clary sage oil were assayed by GC-FID-MS analysis. The minimal inhibitory concentration (MIC) of the tested essential oil against staphylococci by the micro-dilution broth method was determined. The clary sage oil was active against Staphylococcus aureus, S. epidermidis and S. xylosus with MIC values ranging from 3.75 to 7.00 µl/ml. The results of the in vitro tests encourage to use formulations containing sage oil as the active natural antimicrobial agent. Because of its antimicrobial properties clary sage oil may be applied to treat wounds and skin infections.

Constituents of leaves and flowers essential oils of Helichrysum pallasii (Spreng.) Ledeb. growing wild in Lebanon.

PubMed

Formisano, Carmen; Mignola, Enrico; Rigano, Daniela; Senatore, Felice; Arnold, Nelly Apostolides; Bruno, Maurizio; Rosselli, Sergio

2009-02-01

The chemical compositions of the essential oils obtained from leaves and flowers of Helichrysum pallasii were analyzed by gas chromatography and gas chromatography-mass spectrometry. Among the 102 identified constituents, hexadecanoic acid (16.2%), (Z,Z)-9,12-octadecadienoic acid (6.8%), tetradecanoic acid (2.6%), and (Z)-caryophyllene (4.2%) were the main constituent of the oil from leaves, while in the oil from flowers hexadecanoic acid (14.7%), (Z,Z)-9,12-octadecadienoic acid (14.2%), (Z)-caryophyllene (3.6%), and delta-cadinene (3.1%) predominated. The oils were both characterized by sesquiterpenes (33.4% for leaves and 33.7% for flowers, respectively) and fatty acids and esters (30.3% in leaves and 35% in flowers, respectively). The in vitro activity of the essential oils of the plant against some microorganisms in comparison with chloramphenicol by the broth dilution method was determined. The oils exhibited a weak activity as inhibitors of growth of Staphylococcus epidermidis in vitro (minimum inhibitory concentration = 100 microg/mL).

Assessment of antinociceptive, antipyretic and antimicrobial activity of Piper cubeba L. essential oil in animal models.

PubMed

Mothana, Ramzi; Alsaid, Mansour; Khaled, Jamal M; Alharbi, Naiyf S; Alatar, Abdulrahman; Raish, Mohammad; Al-Yahya, Mohammed; Rafatullah, Syed; Parvez, Mohammad Khalid; Ahamad, Syed Rizwan

2016-03-01

This study was designed to investigate the possible antiniciceptive, antipyretic and antimicrobial activities of the essential oil obtained from the fruits of Piper Cubeba (L.). To assess the antinociceptive and antipyretic activities, three doses (150, 300 and 600 mg/kg, i.p.) were tested in acetic acid-induced abdominal writhing, tail flick reaction and hot-plate and Brewer's yeast-induced hyperpyrexia test models in animals. Moreover, the antimicrobial activity was examined using agar diffusion method and broth micro-dilution assay for minimum inhibitory concentrations (MIC). The Piper Cubeba essential oil (PCEO) showed a marked antinociception (17, 30 and 54%) and an increase in reaction time in mice in the flick tailed and hot-plate tests. The brewer's yeast induced hyperpyrexia was decreased in a dose dependent manner. PCEO also exhibited a strong antimicrobial potential. These findings confirm the traditional analgesic indications of P. cubeba oil and provide persuasive evidence and support its use in Arab traditional medicine.

Antimicrobial effect against different bacterial strains and bacterial adaptation to essential oils used as feed additives.

PubMed

Melo, Antonio Diego Brandão; Amaral, Amanda Figueiredo; Schaefer, Gustavo; Luciano, Fernando Bittencourt; de Andrade, Carla; Costa, Leandro Batista; Rostagno, Marcos Horácio

2015-10-01

The aim of this study was to evaluate the antimicrobial activity and determine the minimum bactericidal concentration (MBC) of the essential oils derived from Origanum vulgare (oregano), Melaleuca alternifolia (tea tree), Cinnamomum cassia (cassia), and Thymus vulgaris (white thyme) against Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis. The study also investigated the ability of these different bacterial strains to develop adaptation after repetitive exposure to sub-lethal concentrations of these essential oils. The MBC of the essential oils studied was determined by disc diffusion and broth dilution methods. All essential oils showed antimicrobial effect against all bacterial strains. In general, the development of adaptation varied according to the bacterial strain and the essential oil (tea tree > white thyme > oregano). Therefore, it is important to use essential oils at efficient bactericidal doses in animal feed, food, and sanitizers, since bacteria can rapidly develop adaptation when exposed to sub-lethal concentrations of these oils.

Antimicrobial effect against different bacterial strains and bacterial adaptation to essential oils used as feed additives

PubMed Central

Melo, Antonio Diego Brandão; Amaral, Amanda Figueiredo; Schaefer, Gustavo; Luciano, Fernando Bittencourt; de Andrade, Carla; Costa, Leandro Batista; Rostagno, Marcos Horácio

2015-01-01

The aim of this study was to evaluate the antimicrobial activity and determine the minimum bactericidal concentration (MBC) of the essential oils derived from Origanum vulgare (oregano), Melaleuca alternifolia (tea tree), Cinnamomum cassia (cassia), and Thymus vulgaris (white thyme) against Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis. The study also investigated the ability of these different bacterial strains to develop adaptation after repetitive exposure to sub-lethal concentrations of these essential oils. The MBC of the essential oils studied was determined by disc diffusion and broth dilution methods. All essential oils showed antimicrobial effect against all bacterial strains. In general, the development of adaptation varied according to the bacterial strain and the essential oil (tea tree > white thyme > oregano). Therefore, it is important to use essential oils at efficient bactericidal doses in animal feed, food, and sanitizers, since bacteria can rapidly develop adaptation when exposed to sub-lethal concentrations of these oils. PMID:26424908

Development and evaluation of the quick anaero-system-a new disposable anaerobic culture system.

PubMed

Yang, Nam Woong; Kim, Jin Man; Choi, Gwang Ju; Jang, Sook Jin

2010-04-01

We developed a new disposable anaerobic culture system, namely, the Quick anaero-system, for easy culturing of obligate anaerobes. Our system consists of 3 components: 1) new disposable anaerobic gas pack, 2) disposable culture-envelope and sealer, and 3) reusable stainless plate rack with mesh containing 10 g of palladium catalyst pellets. To evaluate the efficiency of our system, we used 12 anaerobic bacteria. We prepared 2 sets of ten-fold serial dilutions of the 12 anaerobes, and inoculated these samples on Luria-Bertani (LB) broth and LB blood agar plate (LB-BAP) (BD Diagnostic Systems, USA). Each set was incubated in the Quick anaero-system (DAS Tech, Korea) and BBL GasPak jar with BD GasPak EZ Anaerobe Container System (BD Diagnostic Systems) at 35-37 degrees C for 48 hr. The minimal inoculum size showing visible growth of 12 anaerobes when incubated in both the systems was compared. The minimal inoculum size showing visible growth for 2 out of the 12 anaerobes in the LB broth and 9 out of the 12 anaerobes on LB-BAP was lower for the Quick anaero-system than in the BD GasPak EZ Anaerobe Container System. The mean time (+/-SD) required to achieve absolute anaerobic conditions of the Quick anaero-system was 17 min and 56 sec (+/-3 min and 25 sec). The Quick anaero-system is a simple and effective method of culturing obligate anaerobes, and its performance is superior to that of the BD GasPak EZ Anaerobe Container System.

Trans-Cinnamaldehyde and Eugenol Increase Acinetobacter baumannii Sensitivity to Beta-Lactam Antibiotics.

PubMed

Karumathil, Deepti P; Nair, Meera Surendran; Gaffney, James; Kollanoor-Johny, Anup; Venkitanarayanan, Kumar

2018-01-01

Multi-drug resistant (MDR) Acinetobacter baumannii is a major nosocomial pathogen causing a wide range of clinical conditions with significant mortality rates. A. baumannii strains are equipped with a multitude of antibiotic resistance mechanisms, rendering them resistant to most of the currently available antibiotics. Thus, there is a critical need to explore novel strategies for controlling antibiotic resistance in A. baumannii . This study investigated the efficacy of two food-grade, plant-derived antimicrobials (PDAs), namely trans -cinnamaldehyde (TC) and eugenol (EG) in decreasing A. baumannii 's resistance to seven β-lactam antibiotics, including ampicillin, methicillin, meropenem, penicillin, aztreonam, amoxicillin, and piperacillin. Two MDR A. baumannii isolates (ATCC 17978 and AB 251847) were separately cultured in tryptic soy broth (∼6 log CFU/ml) containing the minimum inhibitory concentration (MIC) of TC or EG with or without the MIC of each antibiotic at 37°C for 18 h. A. baumannii strains not exposed to the PDAs or antibiotics served as controls. Following incubation, A. baumannii counts were determined by broth dilution assay. In addition, the effect of PDAs on the permeability of outer membrane and efflux pumps in A. baumannii was measured. Further, the effect of TC and EG on the expression of A. baumannii genes encoding resistance to β-lactam antibiotics ( blaP ), efflux pumps ( adeABC ), and multi-drug resistant protein ( mdrp ) was studied using real-time quantitative PCR (RT-qPCR). The experiment was replicated three times with duplicate samples of each treatment and control. The results from broth dilution assay indicated that both TC and EG in combination with antibiotics increased the sensitivity of A. baumannii to all the tested antibiotics ( P < 0.05). The two PDAs inhibited the function of A. baumannii efflux pump, (AdeABC), but did not increase the permeability of its outer membrane. Moreover, RT-qPCR data revealed that TC and EG down-regulated the expression of majority of the genes associated with β-lactam antibiotic resistance, especially blaP and adeABC ( P < 0.05). The results suggest that TC and EG could potentially be used along with β-lactam antibiotics for controlling MDR A. baumannii infections; however, their clinical significance needs to be determined using in vivo studies.

Block Copolymer Membranes for Biofuel Purification

NASA Astrophysics Data System (ADS)

Evren Ozcam, Ali; Balsara, Nitash

2012-02-01

Purification of biofuels such as ethanol is a matter of considerable concern as they are produced in complex multicomponent fermentation broths. Our objective is to design pervaporation membranes for concentrating ethanol from dilute aqueous mixtures. Polystyrene-b-polydimethylsiloxane-b-polystyrene block copolymers were synthesized by anionic polymerization. The polydimethylsiloxane domains provide ethanol-transporting pathways, while the polystyrene domains provide structural integrity for the membrane. The morphology of the membranes is governed by the composition of the block copolymer while the size of the domains is governed by the molecular weight of the block copolymer. Pervaporation data as a function of these two parameters will be presented.

Pneumonia and bacteremia caused by a previously undescribed Moraxella-like bacterium.

PubMed Central

Goetz, M B; Jones, J

1982-01-01

Immunocompromised patients are frequently subject to unusual infections. We recently treated a renal allograft recipient for pneumonia due to a hitherto undescribed Moraxella-like bacterium which most closely resembles M-5. M-5 has previously been associated in humans only with dog bites and wound infections. The patient responded well to treatment with aminoglycosides and cephalosporins. Susceptibility to these drugs was demonstrated in vitro by a broth dilution technique. On the basis of the known ability of Moraxella species to colonize the oropharynx and the patient's lack of animal exposure, we propose that our patient's illness was secondary to aspiration of colonized oropharyngeal contents. Images PMID:7040467

Automated reading of MIC microdilution trays containing fluorogenic enzyme substrates with the Sensititre Autoreader.

PubMed Central

Staneck, J L; Allen, S D; Harris, E E; Tilton, R C

1985-01-01

The Sensititre Autoreader is a microcomputer-driven instrument capable of automatically reading antimicrobial susceptibility microdilution trays. The instrument measures the fluorescence liberated by bacterial enzymatic activity on fluorogenic substrates as an indicator of growth in each well. A mathematical algorithm converts the fluorescent signals from an antimicrobial dilution series to an MIC endpoint. A three-center study evaluated the performance of the Autoreader in comparison with MIC determined visually in a duplicate set of control plates lacking fluorogenic substrate. Among 828 isolates of gram-negative bacilli tested against 17 antimicrobial agents, Autoreader 18-h MIC were within +/- 1 twofold dilution of control MIC values (agreement) in 95.3% of instances. In 3.5% of the instances, Autoreader values occurred +/- 2 half-step dilutions from control values (minor discrepancy), and in only 1.2% of instances did Autoreader values deviate from control values by greater than +/- 2 dilution steps (major discrepancy). Agreement, minor discrepancies, and major discrepancies were noted among 148 gram-positive cocci tested against 11 antimicrobial agents in 93.5, 4.8, and 1.7% of the instances, respectively. Over half of the major discrepancies noted with gram-negative bacilli occurred with Proteus mirabilis-beta-lactam combinations, a problem that was resolved when a lower initial inoculum was used. Inter-and intralaboratory reproducibility was excellent. Standard Sensititre susceptibility trays may be instrument read at 18 h reproducibly and accurately with only slight modification of conventional procedures to include fluorogenic enzyme substrates in the incubation broth. PMID:4031033

Development of a Novel Screening Method for the Isolation of “Cronobacter” spp. (Enterobacter sakazakii)▿

PubMed Central

Iversen, Carol; Druggan, Patrick; Schumacher, Sandra; Lehner, Angelika; Feer, Claudia; Gschwend, Karl; Joosten, Han; Stephan, Roger

2008-01-01

A differential medium, “Cronobacter” screening broth, has been designed to complement agars based on hydrolysis of chromogenic α-glucopyranoside substrates. The broth was evaluated using 329 Enterobacteriaceae strains (229 target isolates), spiked/naturally contaminated samples, and a parallel comparison with current methods for raw materials, line/end products, and factory environment samples. PMID:18310415

A Single-Step Enrichment Medium for Nonchromogenic Isolation of Healthy and Cold-Injured Salmonella spp. from Fresh Vegetables.

PubMed

Kim, Hong-Seok; Choi, Dasom; Kang, Il-Byeong; Kim, Dong-Hyeon; Yim, Jin-Hyeok; Kim, Young-Ji; Chon, Jung-Whan; Oh, Deog-Hwan; Seo, Kun-Ho

2017-02-01

Culture-based detection of nontyphoidal Salmonella spp. in foods requires at least four working days; therefore, new detection methods that shorten the test time are needed. In this study, we developed a novel single-step Salmonella enrichment broth, SSE-1, and compared its detection capability with that of commercial single-step ONE broth-Salmonella (OBS) medium and a conventional two-step enrichment method using buffered peptone water and Rappaport-Vassiliadis soy broth (BPW-RVS). Minimally processed lettuce samples were artificially inoculated with low levels of healthy and cold-injured Salmonella Enteritidis (10 0 or 10 1 colony-forming unit/25 g), incubated in OBS, BPW-RVS, and SSE-1 broths, and streaked on xylose lysine deoxycholate (XLD) agar. Salmonella recoverability was significantly higher in BPW-RVS (79.2%) and SSE-1 (83.3%) compared to OBS (39.3%) (p < 0.05). Our data suggest that the SSE-1 single-step enrichment broth could completely replace two-step enrichment with reduced enrichment time from 48 to 24 h, performing better than commercial single-step enrichment medium in the conventional nonchromogenic Salmonella detection, thus saving time, labor, and cost.

Activities of E1210 and comparator agents tested by CLSI and EUCAST broth microdilution methods against Fusarium and Scedosporium species identified using molecular methods.

PubMed

Castanheira, Mariana; Duncanson, Frederick P; Diekema, Daniel J; Guarro, Josep; Jones, Ronald N; Pfaller, Michael A

2012-01-01

Fusarium (n = 67) and Scedosporium (n = 63) clinical isolates were tested by two reference broth microdilution (BMD) methods against a novel broad-spectrum (active against both yeasts and molds) antifungal, E1210, and comparator agents. E1210 inhibits the inositol acylation step in glycophosphatidylinositol (GPI) biosynthesis, resulting in defects in fungal cell wall biosynthesis. Five species complex organisms/species of Fusarium (4 isolates unspeciated) and 28 Scedosporium apiospermum, 7 Scedosporium aurantiacum, and 28 Scedosporium prolificans species were identified by molecular techniques. Comparator antifungal agents included anidulafungin, caspofungin, itraconazole, posaconazole, voriconazole, and amphotericin B. E1210 was highly active against all of the tested isolates, with minimum effective concentration (MEC)/MIC(90) values (μg/ml) for E1210, anidulafungin, caspofungin, itraconazole, posaconazole, voriconazole, and amphotericin B, respectively, for Fusarium of 0.12, >16, >16, >8, >8, 8, and 4 μg/ml. E1210 was very potent against the Scedosporium spp. tested. The E1210 MEC(90) was 0.12 μg/ml for S. apiospermum, but 1 to >8 μg/ml for other tested agents. Against S. aurantiacum, the MEC(50) for E1210 was 0.06 μg/ml versus 0.5 to >8 μg/ml for the comparators. Against S. prolificans, the MEC(90) for E1210 was only 0.12 μg/ml, compared to >4 μg/ml for amphotericin B and >8 μg/ml for itraconazole, posaconazole, and voriconazole. Both CLSI and EUCAST methods were highly concordant for E1210 and all comparator agents. The essential agreement (EA; ±2 doubling dilutions) was >93% for all comparisons, with the exception of posaconazole and F. oxysporum species complex (SC) (60%), posaconazole and S. aurantiacum (85.7%), and voriconazole and S. aurantiacum (85.7%). In conclusion, E1210 exhibited very potent and broad-spectrum antifungal activity against azole- and amphotericin B-resistant strains of Fusarium spp. and Scedosporium spp. Furthermore, in vitro susceptibility testing of E1210 against isolates of Fusarium and Scedosporium may be accomplished using either of the CLSI or EUCAST BMD methods, each producing very similar results.

Activities of E1210 and Comparator Agents Tested by CLSI and EUCAST Broth Microdilution Methods against Fusarium and Scedosporium Species Identified Using Molecular Methods

PubMed Central

Duncanson, Frederick P.; Diekema, Daniel J.; Guarro, Josep; Jones, Ronald N.; Pfaller, Michael A.

2012-01-01

Fusarium (n = 67) and Scedosporium (n = 63) clinical isolates were tested by two reference broth microdilution (BMD) methods against a novel broad-spectrum (active against both yeasts and molds) antifungal, E1210, and comparator agents. E1210 inhibits the inositol acylation step in glycophosphatidylinositol (GPI) biosynthesis, resulting in defects in fungal cell wall biosynthesis. Five species complex organisms/species of Fusarium (4 isolates unspeciated) and 28 Scedosporium apiospermum, 7 Scedosporium aurantiacum, and 28 Scedosporium prolificans species were identified by molecular techniques. Comparator antifungal agents included anidulafungin, caspofungin, itraconazole, posaconazole, voriconazole, and amphotericin B. E1210 was highly active against all of the tested isolates, with minimum effective concentration (MEC)/MIC90 values (μg/ml) for E1210, anidulafungin, caspofungin, itraconazole, posaconazole, voriconazole, and amphotericin B, respectively, for Fusarium of 0.12, >16, >16, >8, >8, 8, and 4 μg/ml. E1210 was very potent against the Scedosporium spp. tested. The E1210 MEC90 was 0.12 μg/ml for S. apiospermum, but 1 to >8 μg/ml for other tested agents. Against S. aurantiacum, the MEC50 for E1210 was 0.06 μg/ml versus 0.5 to >8 μg/ml for the comparators. Against S. prolificans, the MEC90 for E1210 was only 0.12 μg/ml, compared to >4 μg/ml for amphotericin B and >8 μg/ml for itraconazole, posaconazole, and voriconazole. Both CLSI and EUCAST methods were highly concordant for E1210 and all comparator agents. The essential agreement (EA; ±2 doubling dilutions) was >93% for all comparisons, with the exception of posaconazole and F. oxysporum species complex (SC) (60%), posaconazole and S. aurantiacum (85.7%), and voriconazole and S. aurantiacum (85.7%). In conclusion, E1210 exhibited very potent and broad-spectrum antifungal activity against azole- and amphotericin B-resistant strains of Fusarium spp. and Scedosporium spp. Furthermore, in vitro susceptibility testing of E1210 against isolates of Fusarium and Scedosporium may be accomplished using either of the CLSI or EUCAST BMD methods, each producing very similar results. PMID:22083469

A comparative study of biofilm formation by Shiga toxigenic Escherichia coli using epifluorescence microscopy on stainless steel and a microtitre plate method.

PubMed

Rivas, Lucia; Dykes, Gary A; Fegan, Narelle

2007-04-01

Attachment of Shiga toxigenic Escherichia coli (STEC) to surfaces and the formation of biofilms may enhance persistence in a food processing environment and present a risk of contaminating products. Seven strains of STEC and three non-STEC strains were selected to compare two biofilm quantification methods; epifluorescence microscopy on stainless steel (SS) and a microtitre plate assay. The influence of prior growth in planktonic (nutrient broth) and sessile (nutrient agar) culture on biofilm production, as well as expression of surface structures and the possession of antigen 43 (encoded by agn43) on biofilm formation were also investigated. Biofilms were produced in diluted nutrient broth at 25 degrees C for 24 and 48 h. Curli expression was determined using congo red indicator agar, while the presence of agn43 was determined using polymerase chain reaction. No correlation was found between counts for epifluorescence microscopy on SS and the absorbance values obtained with the microtitre plate method for planktonic and sessile grown cultures. Different abilities of individual STEC strains to attach to SS and microtitre plates were found with some strains attaching better to each surface following growth in either planktonic or sessile culture. All O157 STEC strains had low biofilm counts on SS for planktonic and sessile grown cultures; however, one STEC O157:H- strain (EC516) had significantly greater (p<0.05) biofilm production on microtitre plates compared to the other O157 STEC strains. EC516 and other STEC (O174:H21 and O91:H21) strains expressing curli fimbriae were found to produce significantly greater (p<0.05) biofilms on microtitre plates compared to the non-curli expressing strains. No relationship was found between the production of type-I fimbriae, motility, agn43 and bacterial physicochemical properties (previously determined) and biofilm formation on SS or microtitre plates. Variations between the two biofilm determination methods may suggest that the biofilm production on microtitre plates may not be appropriate to represent other surfaces such as SS and that caution should be taken when selecting a method to quantify biofilm production on a surface.

Effect of beef broth protein on the thermal inactivation of staphylococcal enterotoxin B1.

PubMed Central

Lee, I C; Stevenson, K E; Harmon, L G

1977-01-01

Enterotoxin B produced by Staphylococus aureus 243 in brain heart infusion broth was concentrated by dialysis against 40% polyethylene glycol (20 M), partially purified on a Sephadex G-100 column and heated at 110 degrees C in thermal death time cans. Various heating menstrua included 0.04 M Veronal buffer (pH 7.4), beef broth, and fractions of beef broth obtained by ultrafiltration or precipitation with ammonium sulfate. The toxin was assayed serologically using the microslide gel double-diffusion method. The time requiring for 90% inactivation at 110 degrees C (D110 value) obtained in buffer and in beef broth was 18 and 60 min, respectively. When the concentration of beef broth was increased fivefold, the D110 increased to 78 min. The apparent protective effect or protein was further investigated using beef broth protein obtained by precipitation with (NH4)2SO4. The D110 values were 51 and 70 min when the protein concentration in the heating menstruum was 3.8 and 7.7 mg/ml, respectively. However, when the beef broth protein was dialyzed against buffer before use as a heating menstrum, the D110 was only 39 or 41 min at comparable protein concentrations. Results indicated a dialyzable factor, whose protective effect was partially destroyed by trypsin and chymotrypsin but did not by disodium ethylenediaminetetraacetate, was involved in the protection of enterotoxin B during heating. PMID:403860

Comparison of direct-plating and broth-enrichment culture methods for detection of potential bacterial pathogens in respiratory secretions.

PubMed

Kaur, Ravinder; Wischmeyer, Jareth; Morris, Matthew; Pichichero, Michael E

2017-11-01

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.

Essential and toxic metals in animal bone broths

PubMed Central

Hsu, Der-jen; Lee, Chia-wei; Tsai, Wei-choung; Chien, Yeh-chung

2017-01-01

ABSTRACT Background: This investigation examines the extraction of metals from animal bones into broth, and assesses whether bone broths are good sources of essential metals and the risks associated with the consumption of toxic metals. Method:Three sets of controlled experiments were performed to study the factors (cooking time, acidity, bone type and animal species) that influence metal extractions. Three types of animal bone broth-based foods were also tested. Results: Reducing the broth pH from 8.38 to 5.32 significantly (p < 0.05) increased Ca and Mg extraction by factors of 17.4 and 15.3, respectively. A long cooking time, > 8 h, yielded significantly higher (p < 0.05) Ca and Mg extraction than shorter cooking times. The extraction characteristics of metals, particularly Ca, Mg, Cu and Al, from the leg and rib bones differed. The between-species variations in extraction were larger than those of within-species. Conclusions:The Ca and Mg levels in home-made or commercial broth/soup were found not to exceed low tenths of milligram per serving, or <5% of the daily recommended levels. The risks that are associated with the ingestion of heavy metals such as Pb and Cd in broth are minimal because the levels were in the ranges of a few μg per serving. PMID:28804437

Honey Bee as Alternative Medicine to Treat Eleven Multidrug-Resistant Bacteria Causing Urinary Tract Infection during Pregnancy.

PubMed

Bouacha, Mabrouka; Ayed, Hayette; Grara, Nedjoud

2018-04-13

Medicinal benefits of honey bee have been recognized in the medical community since ancient times as a remedy for many diseases and infections. This study aimed to investigate the in vitro susceptibility of 11 multidrug-resistant bacterial strains, isolated from urinary tract infections of pregnant women, to six honey samples collected from different localities in the east of Algeria. The evaluation of the antibacterial activity was performed by the well method followed by the broth dilution method using two-fold dilutions of each honey sample ranging from 2.5 to 80% (w/v). The results obtained in this study revealed that all tested honeys exhibited potent antibacterial activity against the tested strains. The diameters of inhibition ranged from 19.67 to 53.33 mm, with minimum inhibitory concentrations (MICs) ranging from 2.5 to 40% (w/v) and minimum bactericidal concentration (MBCs) varied between 2.5 and 80% (w/v). Gram-positive bacteria were found to be more susceptible than Gram-negative bacteria with diameters ranging from 43.33 to 53.33 mm; MIC and MBC values ranged from 2.5 to 5% (w/v). The P.aeruginosa strain was found to be less susceptible than other strains with inhibitory diameters ranging from 19.67 to 27.33 mm; MICs ranged from 20 to 40% and MBCs ranged from 20 to 80% ( w/v ). This contribution has provided a broad overview of the antibacterial activity of Algerian honey and shown that honey bee has great potential for therapeutic use as an alternative therapy for urinary tract infection treatment which is safe and efficient during pregnancy.

In vitro antimicrobial activity of natural toxins and animal venoms tested against Burkholderia pseudomallei

PubMed Central

Perumal Samy, R; Pachiappan, A; Gopalakrishnakone, P; Thwin, Maung M; Hian, Yap E; Chow, Vincent TK; Bow, Ho; Weng, Joseph T

2006-01-01

Background Burkholderia pseudomallei are the causative agent of melioidosis. Increasing resistance of the disease to antibiotics is a severe problem in treatment regime and has led to intensification of the search for new drugs. Antimicrobial peptides are the most ubiquitous in nature as part of the innate immune system and host defense mechanism. Methods Here, we investigated a group of venoms (snakes, scorpions and honey bee venoms) for antimicrobial properties against two strains of Gram-negative bacteria Burkholderia pseudomallei by using disc-diffusion assay for in vitro susceptibility testing. The antibacterial activities of the venoms were compared with that of the isolated L-amino acid oxidase (LAAO) and phospholipase A2 (PLA2s) enzymes. MICs were determined using broth dilution method. Bacterial growth was assessed by measurement of optical density at the lowest dilutions (MIC 0.25 mg/ml). The cell viability was measured using tetrazolium salts (XTT) based cytotoxic assay. Results The studied venoms showed high antimicrobial activity. The venoms of C. adamanteus, Daboia russelli russelli, A. halys, P. australis, B. candidus and P. guttata were equally as effective as Chloramphenicol and Ceftazidime (30 μg/disc). Among those tested, phospholipase A2 enzymes (crotoxin B and daboiatoxin) showed the most potent antibacterial activity against Gram-negative (TES) bacteria. Naturally occurring venom peptides and phospholipase A2 proved to possess highly potent antimicrobial activity against Burkholderia pseudomallei. The XTT-assay results showed that the cell survival decreased with increasing concentrations (0.05–10 mg/mL) of Crotalus adamanteus venom, with no effect on the cell viability evident at 0.5 mg/mL. Conclusion This antibacterial profile of snake venoms reported herein will be useful in the search for potential antibacterial agents against drug resistant microorganisms like B. pseudomallei. PMID:16784542

Antioxidant and antibacterial activity of Thai medicinal plant (Capparis micracantha)

NASA Astrophysics Data System (ADS)

Laoprom, Nonglak; Sangprom, Araya; Chaisri, Patcharaporn

2018-04-01

This work aims to study the antioxidants capacity, Total phenolic content and antibacterial activity of Thai medicinal plant for the treatment of dermatitis-related inflammations, Capparis micracantha. Crude extract from stem of Thai medicinal plant was extracted with hexane, ethyl acetate, methanol and water. The antioxidant activities (IC50) was evaluated with 1,1-diphenyl-1-princylhydrazyl (DPPH) radical scavenging assay. Total phenolic content (TPC) was determined by using Folin-Ciocalteu method. Bacterial activities was tested with four human pathogenic bacteria; Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Stapylococcus epidermidis by using agar diffusion assay. Minimum Inhibition Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were also determined by broth dilution method. For antioxidant activity, the methanol fraction from stem extract showed the highest activity with an IC50 of 2.4 mg/ml. Water extraction was the high TPC with 10,136.9 mg GAE/g dry weight. Methanol and water extraction showed the remarkable inhibition of bacterial growth was shown against L. monocytogenes and S. aureus. In addition, ethyl acetate, methanol and water fraction from stem extract against S. epidermidis. The present finding suggests that the extract of C. micracantha could be used to discover bioactive natural products that may serve as pharmaceutical products.

In-vitro propagation and antimycotic potential of extracts and essential oil of roots of Aristolochia bracteolata Linn. (Aristolochiaceae).

PubMed

Gbadamosi, I T; Egunyomi, A

2012-01-01

In spite of the therapeutic importance of Aristolochia bracteolata Linn. in Nigerian ethnomedicine, it is largely collected from the wild. Owing to the acclaimed potency of the plant and the difficulty in treating candidiasis, the anticandidal activity and in vitro propagation of the plant were investigated. Phytochemical screening and preparation of extracts of the roots were done using standard procedures. Clinical isolates of Candida albicans were screened against extracts and essential oil of Aristolochia bracteolata root using agar-well diffusion method. Minimum Inhibitory Concentration (MIC) of the ethanol extract was determined using broth dilution method. The nodal cuttings of A. bracteolata were cultured on Murashige and Skoog (MS) basal media. A. bracteolata contained alkaloids, saponins and cardenolides. The water extract was inactive on all isolates. The ethanol extract (500 mg/ml) and essential oil (undiluted) exhibited anticandidal activity on 9 out of 10 isolates at 10(1) - 10(6) cfu/ml inoculums concentration. Green growth and callus formation were observed in explants cultured on MS basal media after 30 days. A. bracteolata could be a source of anticandidal phytomedicine and the in vitro propagation confirmed its sustainability as anticandidal agent.

Effects of Vernonia cinerea less methanol extract on growth and morphogenesis of Candida albicans.

PubMed

Latha, L Yoga; Darah, I; Jain, K; Sasidharan, S

2011-05-01

Vernonia (V.) cinerea Less (Asteraceae) have many therapeutic uses in the practice of traditional medicine. The methanol extract of V cinerea, was screened for antiyeast activity against pathogenic yeast Candida albicans. The antimicrobial activities were studied by using disc diffusion method and broth dilution method. The effect of the extract on the growth profile of the yeast was also examined via time-kill assay. In addition to the fungicidal effects study, microscopic observations using Scanning (SEM) electron microscopy, Transmission (TEM) electron microscopy and light microscopy (LM) were done to determine the major alterations in the microstructure of Candida (C) albicans. The extract showed a favorable antimicrobial activity against C. albicans with a minimum inhibitory concentration (MIC) value of 1.56 mg/mL. Time-kill assay suggested that Vernonia cinerea extract had completely inhibited Candida albicans growth and also exhibited prolonged antiyeast activity. The main abnormalities notes from these microscopic observations were the alterations in morphology and complete collapse of the yeast cells after 36 h of exposure to the extract. The extract of Vernonia cinerea may be an effective agent to treat the Candida albicans infection.

Use of L-Glutamic Acid in a New Enrichment Broth (R-TATP Broth) for Detecting the Presence or Absence of Molds in Raw Ingredients/Personal Care Product Formulations by Using an ATP Bioluminescence Assay.

PubMed

Yang, Youjun; English, Donald J

The present study reports the effects of adding L-glutamic acid to a new enrichment broth designated as R-TATP broth, to promote the growth of slow-growing mold microorganisms such as Aspergillus brasiliensis and Aspergillus oryzae , without interfering in the growth of other types of microorganisms. This L-glutamic acid containing enrichment broth would be particularly valuable in a rapid microbial detection assay such as an adenosine triphosphate (ATP) bioluminescence assay. By using this new enrichment broth, the amount of ATP (represented as relative light unit ratio after normalized with the negative test control) from mold growth was significantly increased by reducing the time of detection of microbial contamination in a raw ingredient or personal care product formulation from an incubation period of 48-18 h. By using L-glutamic acid in this enrichment broth, the lag phase of the mold growth cycle was shortened. In response to various concentrations of L-glutamic acid in R-TATP broth, there was an increased amount of ATP that had been produced by mold metabolism in an ATP bioluminescence assay. By using L-glutamic acid in R-TATP broth in an ATP bioluminescence assay, the presence of mold could be detected in 18 h as well as other types of microorganisms that may or may not be present in a test sample. By detecting the presence or absence of microbial contamination in 18 h, it is superior in comparison to a 48-96 h incubation period by using either a standard or rapid detection method.

Quality control ranges for testing broth microdilution susceptibility of Flavobacterium columnare and F. psychrophilium to nine antimicrobials

USDA-ARS?s Scientific Manuscript database

A multi-laboratory broth microdilution method trial was performed to standardize the specialized test conditions required for fish pathogens Flavobacterium columnare and F. pyschrophilum. Nine laboratories tested the quality control (QC) strains Escherichia coli ATCC 25922 and Aeromonas salmonicid...

Activity of plant flavonoids against antibiotic-resistant bacteria.

PubMed

Xu, H X; Lee, S F

2001-02-01

Thirty eight plant-derived flavonoids representing seven different structural groups were tested for activities against antibiotic-resistant bacteria using the disc-diffusion assay and broth dilution assay. Among the flavonoids examined, four flavonols (myricetin, datiscetin, kaempferol and quercetin) and two -flavones (flavone and luteolin) exhibited inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA). Myricetin was also found to inhibit the growth of multidrug-resistant Burkholderia -cepacia, vancomycin-resistant enterococci (VRE) and other medically important organisms such as -Klebsiella pneumoniae and Staphylococcus epidermidis. Myricetin was bactericidal to B. cepacia. The results of the radiolabel incorporation assay showed that myricetin inhibited protein synthesis by -B. cepacia. The structure-activity relationship of these flavonoids is discussed. Copyright 2001 John Wiley & Sons, Ltd.

Antimicrobial activity of grapefruit seed and pulp ethanolic extract.

PubMed

Cvetnić, Zdenka; Vladimir-Knezević, Sanda

2004-09-01

Antibacterial and antifungal activity of ethanolic extract of grapefruit (Citrus paradisi Macf., Rutaceae) seed and pulp was examined against 20 bacterial and 10 yeast strains. The level of antimicrobial effects was established using an in vitro agar assay and standard broth dilution susceptibility test. The contents of 3.92% of total polyphenols and 0.11% of flavonoids were determined spectrometrically in crude ethanolic extract. The presence of flavanones naringin and hesperidin in the extract was confirmed by TLC analysis. Ethanolic extract exibited the strongest antimicrobial effect against Salmonella enteritidis (MIC 2.06%, m/V). Other tested bacteria and yeasts were sensitive to extract concentrations ranging from 4.13% to 16.50% (m/V).

Removal of heavy metals from polluted soil using the citric acid fermentation broth: a promising washing agent.

PubMed

Zhang, Hongjiao; Gao, Yuntao; Xiong, Huabin

2017-04-01

The citric acid fermentation broth was prepared and it was employed to washing remediation of heavy metal-polluted soil. A well-defined washing effect was obtained, the removal percentages using citric acid fermentation broth are that 48.2% for Pb, 30.6% for Cu, 43.7% for Cr, and 58.4% for Cd and higher than that using citric acid solution. The kinetics of heavy metals desorption can be described by the double constant equation and Elovich equation and is a heterogeneous diffusion process. The speciation analysis shows that the citric acid fermentation broth can effectively reduce bioavailability and environmental risk of heavy metals. Spectroscopy characteristics analysis suggests that the washing method has only a small effect on the mineral composition and does not destroy the framework of soil system. Therefore, the citric acid fermentation broth is a promising washing agent and possesses a potential practical application value in the field of remediation of soils with a good washing performance.

Analysis of lard in meatball broth using Fourier transform infrared spectroscopy and chemometrics.

PubMed

Kurniawati, Endah; Rohman, Abdul; Triyana, Kuwat

2014-01-01

Meatball is one of the favorite foods in Indonesia. For the economic reason (due to the price difference), the substitution of beef meat with pork can occur. In this study, FTIR spectroscopy in combination with chemometrics of partial least square (PLS) and principal component analysis (PCA) was used for analysis of pork fat (lard) in meatball broth. Lard in meatball broth was quantitatively determined at wavenumber region of 1018-1284 cm(-1). The coefficient of determination (R(2)) and root mean square error of calibration (RMSEC) values obtained were 0.9975 and 1.34% (v/v), respectively. Furthermore, the classification of lard and beef fat in meatball broth as well as in commercial samples was performed at wavenumber region of 1200-1000 cm(-1). The results showed that FTIR spectroscopy coupled with chemometrics can be used for quantitative analysis and classification of lard in meatball broth for Halal verification studies. The developed method is simple in operation, rapid and not involving extensive sample preparation. © 2013.

Pre-treatment step with Leuconostoc mesenteroides or L. pseudomesenteroides strains removes furfural from Zymomonas mobilis ethanolic fermentation broth.

PubMed

Hunter, William J; Manter, Daniel K

2014-10-01

Furfural is an inhibitor of growth and ethanol production by Zymomonas mobilis. This study used a naturally occurring (not GMO) biological pre-treatment to reduce that amount of furfural in a model fermentation broth. Pre-treatment involved inoculating and incubating the fermentation broth with strains of Leuconostoc mesenteroides or Leuconostoc pseudomesenteroides. The Leuconostoc strains converted furfural to furfuryl alcohol without consuming large amounts of dextrose in the process. Coupling this pre-treatment to ethanolic fermentation reduced furfural in the broth and improved growth, dextrose uptake and ethanol formation. Pre-treatment permitted ethanol formation in the presence of 5.2 g L(-1) furfural, which was otherwise inhibitive. The pre-treatment and presence of the Leuconostoc strains in the fermentation broth did not interfere with Z. mobilis ethanolic fermentation or the amounts of ethanol produced. The method suggests a possible technique for reducing the effect that furfural has on the production of ethanol for use as a biofuel. Published by Elsevier Ltd.

Study on color identification for monitoring and controlling fermentation process of branched chain amino acid

NASA Astrophysics Data System (ADS)

Ma, Lei; Wang, Yizhong; Chen, Ning; Liu, Tiegen; Xu, Qingyang; Kong, Fanzhi

2008-12-01

In this paper, a new method for monitoring and controlling fermentation process of branched chain amino acid (BCAA) was proposed based on color identification. The color image of fermentation broth of BCAA was firstly taken by a CCD camera. Then, it was changed from RGB color model to HIS color model. Its histograms of hue H and saturation S were calculated, which were used as the input of a designed BP network. The output of the BP network was the description of the color of fermentation broth of BCAA. After training, the color of fermentation broth was identified by the BP network according to the histograms of H and S of a fermentation broth image. Along with other parameters, the fermentation process of BCAA was monitored and controlled to start the stationary phase of fermentation soon. Experiments were conducted with satisfied results to show the feasibility and usefulness of color identification of fermentation broth in fermentation process control of BCAA.

In Vitro Antifungal Activity of KP-103, a Novel Triazole Derivative, and Its Therapeutic Efficacy against Experimental Plantar Tinea Pedis and Cutaneous Candidiasis in Guinea Pigs

PubMed Central

Tatsumi, Yoshiyuki; Yokoo, Mamoru; Arika, Tadashi; Yamaguchi, Hideyo

2001-01-01

The in vitro activity of KP-103, a novel triazole derivative, against pathogenic fungi that cause dermatomycoses and its therapeutic efficacy against plantar tinea pedis and cutaneous candidiasis in guinea pigs were investigated. MICs were determined by a broth microdilution method with morpholinepropanesulfonic acid-buffered RPMI 1640 medium for Candida species and with Sabouraud dextrose broth for dermatophytes and by an agar dilution method with medium C for Malassezia furfur. KP-103 was the most active of all the drugs tested against Candida albicans (geometric mean [GM] MIC, 0.002 μg/ml), other Candida species including Candida parapsilosis and Candida glabrata (GM MICs, 0.0039 to 0.0442 μg/ml), and M. furfur (GM MIC, 0.025 μg/ml). KP-103 (1% solution) was highly effective as a treatment for guinea pigs with cutaneous candidiasis and achieved mycological eradication in 8 of the 10 infected animals, whereas none of the imidazoles tested (1% solutions) was effective in even reducing the levels of the infecting fungi. KP-103 was as active as clotrimazole and neticonazole but was less active than lanoconazole and butenafine against Trichophyton rubrum (MIC at which 80% of isolates are inhibited [MIC80], 0.125 μg/ml) and Trichophyton mentagrophytes (MIC80, 0.25 μg/ml). However, KP-103 (1% solution) exerted therapeutic efficacy superior to that of neticonazole and comparable to those of lanoconazole and butenafine, yielding negative cultures for all samples from guinea pigs with plantar tinea pedis tested. This suggests that KP-103 has better pharmacokinetic properties in skin tissue than the reference drugs. Because the in vitro activity of KP-103, unlike those of the reference drugs, against T. mentagrophytes was not affected by hair as a keratinic substance, its excellent therapeutic efficacy seems to be attributable to good retention of its antifungal activity in skin tissue, in addition to its potency. PMID:11302816

[Effect of home-processing in the preparation of pinto beans (Phaseolus vulgaris L.) on the tannin content and nutritive value of proteins].

PubMed

Goycoolea, F; González de Mejía, E; Barrón, J M; Valencia, M E

1990-06-01

A 3(2) factor design was carried out in order to investigate the different home-cooking treatments applied in the preparation of pinto beans (Phaseolus vulgaris L.) on the nutritive value of their protein. The factors studied were previous soaking, type of cooking and addition of cooking broth. Biological evaluation of the protein was performed, and the protein efficiency ratio (PER) and apparent digestibility of the protein (DAP) values were obtained. The tannin content was measured in hulls, cotyledons and in the cooking broths of each experimental treatment. The most significant effect of the PER value was the type of cooking (P less than 0.0001), followed by the addition of cooking broth (P less than 0.05) as well as a significant interaction between cooking method and addition of broth (P less than 0.025). Soaking did not have significant effects per se or through its interactions in relation to PER. The highest values for PER and DAP were obtained with the boiling treatment without broth. The detrimental effect of the cooking broth can be explained by its tannin content (108.5-272.25 mg Eq. catechin/100g).

Effect of dilute alkaline pretreatment on the conversion of different parts of corn stalk to fermentable sugars and its application in acetone-butanol-ethanol fermentation.

PubMed

Cai, Di; Li, Ping; Luo, Zhangfeng; Qin, Peiyong; Chen, Changjing; Wang, Yong; Wang, Zheng; Tan, Tianwei

2016-07-01

To investigate the effect of dilute alkaline pretreatment on different parts of biomass, corn stalk was separated into flower, leaf, cob, husk and stem, which were treated by NaOH in range of temperature and chemical loading. The NaOH-pretreated solid was then enzymatic hydrolysis and used as the substrate for batch acetone-butanol-ethanol (ABE) fermentation. The results demonstrated the five parts of corn stalk could be used as potential feedstock separately, with vivid performances in solvents production. Under the optimized conditions towards high product titer, 7.5g/L, 7.6g/L, 9.4g/L, 7g/L and 7.6g/L of butanol was obtained in the fermentation broth of flower, leaf, cob, husk and stem hydrolysate, respectively. Under the optimized conditions towards high product yield, 143.7g/kg, 126.3g/kg, 169.1g/kg, 107.7g/kg and 116.4g/kg of ABE solvent were generated, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Testing of Streptococcus pneumoniae for resistance to penicillin.

PubMed Central

Marshall, K J; Musher, D M; Watson, D; Mason, E O

1993-01-01

The increasing prevalence of penicillin-resistant Streptococcus pneumoniae requires antibiotic susceptibility tests that can be done with greater ease and reliability. We measured the MIC of penicillin for pneumococci by the tube macrodilution method with Mueller-Hinton broth (MHB), Haemophilus Test Medium (HTM), Todd-Hewitt broth with 0.5% yeast extract (THY), and MHB with 3% lysed horse blood (LHB). Eight (19%) and 6 (14%) of 42 pneumococcal isolates failed to generate turbid growth in MHB and HTM, respectively, whereas all pneumococcal isolates did so in THY and LHB. For those strains that replicated to turbidity, the mean MICs of penicillin were lower in MHB and HTM than in THY and LHB, with differences being significant (P < 0.05) for comparisons with LHB. Four isolates appeared to be penicillin susceptible in HTM but were actually moderately resistant in THY and LHB, and two isolates appeared to be moderately resistant but were resistant. A similar failure to detect resistance was seen with MHB. S. pneumoniae ATCC 49619, a moderately penicillin-resistant strain that has been proposed for quality control testing, gave variable results in MHB or THM and appeared to be susceptible to penicillin in some assays, whereas the MICs for S. pneumoniae ATCC 49619 in THY or LHB fell within a twofold dilution range, with geometric means of 0.16 and 0.18 micrograms/ml, respectively. Pneumococcal isolates thus may appear falsely susceptible to penicillin when tested in MHB or HTM. LHB remains the standard medium; however, because THY is an easily prepared clear medium that can be used in automated systems and appears to yield results similar to those obtained with LHB, THY deserves consideration for routine use. PMID:8501225

Use of blood-free enrichment broth in the development of a rapid protocol to detect Campylobacter in twenty-five grams of chicken meat.

PubMed

Hayashi, Masahiro; Kubota-Hayashi, Sayoko; Natori, Tatsuya; Mizuno, Takuya; Miyata, Machiko; Yoshida, Shigeru; Zhang, Jiwei; Kawamoto, Keiko; Ohkusu, Kiyofumi; Makino, Souichi; Ezaki, Takayuki

2013-04-15

A Food Pathogen Enrichment (FPE) broth, which supports the growth of Campylobacter without lysed blood and CO2, was developed. The FPE broth supports the growth of Campylobacter to the same degree as Bolton and Preston broths. Using the FPE broth, we developed a novel rapid protocol to detect small numbers of Campylobacter in 25g of food. The sensitivity of FPE enrichment and PCR to detect Campylobacter spp. from spiked chicken meat was determined. The detection sensitivities for non-stressed C. jejuni and C. coli from fresh meat ranged from 5.8 to 1.1×10(1)CFU per 25g of chicken meat, and those for freeze-stressed C. jejuni and C. coli from frozen meat ranged from 9.9×10(1) to 2.0×10(2)CFU. The FPE broth enrichment culture (24h) of chicken meat, followed by PCR, resulted in a significantly higher detection score (80% positive) than conventional Bolton enrichment and subsequent colony isolation using mCCDA agar plates (18% positive). Differences between our new protocol and the Bolton enrichment method were due to the overgrowth of many resistant bacteria, especially extended-spectrum beta-lactamase-producing bacteria in the Bolton enrichment broth. Copyright © 2013 Elsevier B.V. All rights reserved.

Identification and Antimicrobial Susceptibility Testing of Anaerobic Bacteria: Rubik’s Cube of Clinical Microbiology?

PubMed Central

Gajdács, Márió; Spengler, Gabriella; Urbán, Edit

2017-01-01

Anaerobic bacteria have pivotal roles in the microbiota of humans and they are significant infectious agents involved in many pathological processes, both in immunocompetent and immunocompromised individuals. Their isolation, cultivation and correct identification differs significantly from the workup of aerobic species, although the use of new technologies (e.g., matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, whole genome sequencing) changed anaerobic diagnostics dramatically. In the past, antimicrobial susceptibility of these microorganisms showed predictable patterns and empirical therapy could be safely administered but recently a steady and clear increase in the resistance for several important drugs (β-lactams, clindamycin) has been observed worldwide. For this reason, antimicrobial susceptibility testing of anaerobic isolates for surveillance purposes or otherwise is of paramount importance but the availability of these testing methods is usually limited. In this present review, our aim was to give an overview of the methods currently available for the identification (using phenotypic characteristics, biochemical testing, gas-liquid chromatography, MALDI-TOF MS and WGS) and antimicrobial susceptibility testing (agar dilution, broth microdilution, disk diffusion, gradient tests, automated systems, phenotypic and molecular resistance detection techniques) of anaerobes, when should these methods be used and what are the recent developments in resistance patterns of anaerobic bacteria. PMID:29112122

Standardization of Cassia spectabilis with respect to authenticity, assay and chemical constituent analysis.

PubMed

Torey, Angeline; Sasidharan, Sreenivasan; Yeng, Chen; Latha, Lachimanan Yoga

2010-05-10

Quality control standardizations of the various medicinal plants used in traditional medicine is becoming more important today in view of the commercialization of formulations based on these plants. An attempt at standardization of Cassia spectabilis leaf has been carried out with respect to authenticity, assay and chemical constituent analysis. The authentication involved many parameters, including gross morphology, microscopy of the leaves and functional group analysis by Fourier Transform Infrared (FTIR) spectroscopy. The assay part of standardization involved determination of the minimum inhibitory concentration (MIC) of the extract which could help assess the chemical effects and establish curative values. The MIC of the C. spectabilis leaf extracts was investigated using the Broth Dilution Method. The extracts showed a MIC value of 6.25 mg/mL, independent of the extraction time. The chemical constituent aspect of standardization involves quantification of the main chemical components in C. spectabilis. The GCMS method used for quantification of 2,4-(1H,3H)-pyrimidinedione in the extract was rapid, accurate, precise, linear (R(2) = 0.8685), rugged and robust. Hence this method was suitable for quantification of this component in C. spectabilis. The standardization of C. spectabilis is needed to facilitate marketing of medicinal plants, with a view to promoting the export of valuable Malaysian Traditional Medicinal plants such as C. spectabilis.

Identification and Antimicrobial Susceptibility Testing of Anaerobic Bacteria: Rubik's Cube of Clinical Microbiology?

PubMed

Gajdács, Márió; Spengler, Gabriella; Urbán, Edit

2017-11-07

Anaerobic bacteria have pivotal roles in the microbiota of humans and they are significant infectious agents involved in many pathological processes, both in immunocompetent and immunocompromised individuals. Their isolation, cultivation and correct identification differs significantly from the workup of aerobic species, although the use of new technologies (e.g., matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, whole genome sequencing) changed anaerobic diagnostics dramatically. In the past, antimicrobial susceptibility of these microorganisms showed predictable patterns and empirical therapy could be safely administered but recently a steady and clear increase in the resistance for several important drugs (β-lactams, clindamycin) has been observed worldwide. For this reason, antimicrobial susceptibility testing of anaerobic isolates for surveillance purposes or otherwise is of paramount importance but the availability of these testing methods is usually limited. In this present review, our aim was to give an overview of the methods currently available for the identification (using phenotypic characteristics, biochemical testing, gas-liquid chromatography, MALDI-TOF MS and WGS) and antimicrobial susceptibility testing (agar dilution, broth microdilution, disk diffusion, gradient tests, automated systems, phenotypic and molecular resistance detection techniques) of anaerobes, when should these methods be used and what are the recent developments in resistance patterns of anaerobic bacteria.

The antibacterial properties of Malaysian tualang honey against wound and enteric microorganisms in comparison to manuka honey

PubMed Central

Tan, Hern Tze; Rahman, Rosliza Abdul; Gan, Siew Hua; Halim, Ahmad Sukari; Hassan, Siti Asma'; Sulaiman, Siti Amrah; BS, Kirnpal-Kaur

2009-01-01

Background Antibiotic resistance of bacteria is on the rise, thus the discovery of alternative therapeutic agents is urgently needed. Honey possesses therapeutic potential, including wound healing properties and antimicrobial activity. Although the antimicrobial activity of honey has been effectively established against an extensive spectrum of microorganisms, it differs depending on the type of honey. To date, no extensive studies of the antibacterial properties of tualang (Koompassia excelsa) honey on wound and enteric microorganisms have been conducted. The objectives of this study were to conduct such studies and to compare the antibacterial activity of tualang honey with that of manuka honey. Methods Using a broth dilution method, the antibacterial activity of tualang honey against 13 wound and enteric microorganisms was determined; manuka honey was used as the control. Different concentrations of honey [6.25-25% (w/v)] were tested against each type of microorganism. Briefly, two-fold dilutions of honey solutions were tested to determine the minimum inhibitory concentration (MIC) against each type of microorganism, followed by more assays within a narrower dilution range to obtain more precise MIC values. MICs were determined by both visual inspection and spectrophotometric assay at 620 nm. Minimum bactericidal concentration (MBC) also was determined by culturing on blood agar plates. Results By visual inspection, the MICs of tualang honey ranged from 8.75% to 25% compared to manuka honey (8.75-20%). Spectrophotometric readings of at least 95% inhibition yielded MIC values ranging between 10% and 25% for both types of honey. The lowest MBC for tualang honey was 20%, whereas that for manuka honey was 11.25% for the microorganisms tested. The lowest MIC value (8.75%) for both types of honey was against Stenotrophomonas maltophilia. Tualang honey had a lower MIC (11.25%) against Acinetobacter baumannii compared to manuka honey (12.5%). Conclusion Tualang honey exhibited variable activities against different microorganisms, but they were within the same range as those for manuka honey. This result suggests that tualang honey could potentially be used as an alternative therapeutic agent against certain microorganisms, particularly A. baumannii and S. maltophilia. PMID:19754926

Composition analysis and application of degradation products of whole feathers through a large scale of fermentation.

PubMed

Cao, Zhang-Jun; Lu, Dan; Luo, Lai-Sheng; Deng, Yun-Xia; Bian, Yong-Gang; Zhang, Xing-Qun; Zhou, Mei-Hua

2011-08-01

Feathers are one of the most abundant bioresources. They are discarded as waste in most cases and could cause environmental pollution. On the other hand, keratin constituted by amino acids is the main component of feathers. In this article, we reported on biorefined feathers and integrants and application of degraded products. The fermentation of whole chicken feathers with Stenotrophomonas maltophilia DHHJ in a scale-up of a 5-L bioreactor was investigated in this article. The fermentation process was controlled at 0.08 MPa pressure, 2.5 L/min airflow, and 300 rpm as 100% oxygen saturation level, 40°C, and pH 7.8. Feathers were almost completely degraded in the tested fermentation reaction with the following conditions: 80 g of whole feathers in 3 L fermentation broth for 72 h, seed age of 16 h, 100 mL inoculation amount, and 50% oxygen saturation level. The degraded products contain 397.1 mg/L soluble protein that has mass weight ranging from 10 to 160 kD, 336.9 mg/L amino acids, and many kinds of metal ions. The fermentation broth was evaluated as leaf fertilizer and found to increase plant growth to 82% or 66% for two- or fourfold dilutions, respectively. In addition, in a hair care assay, the broth showed a hair protective function by increasing weight, flexibility, and strength of the treated hair. The whole feathers were degraded completely by S. maltophilia DHHJ. The degraded product includes many factors to life, such as peptides, amino acids, and mineral elements. It could be applied as leaf fertilizer and hair care product.

Detection of Listeria monocytogenes from selective enrichment broth using MALDI-TOF Mass Spectrometry.

PubMed

Jadhav, Snehal; Sevior, Danielle; Bhave, Mrinal; Palombo, Enzo A

2014-01-31

Conventional methods used for primary detection of Listeria monocytogenes from foods and subsequent confirmation of presumptive positive samples involve prolonged incubation and biochemical testing which generally require four to five days to obtain a result. In the current study, a simple and rapid proteomics-based MALDI-TOF MS approach was developed to detect L. monocytogenes directly from selective enrichment broths. Milk samples spiked with single species and multiple species cultures were incubated in a selective enrichment broth for 24h, followed by an additional 6h secondary enrichment. As few as 1 colony-forming unit (cfu) of L. monocytogenes per mL of initial selective broth culture could be detected within 30h. On applying the same approach to solid foods previously implicated in listeriosis, namely chicken pâté, cantaloupe and Camembert cheese, detection was achieved within the same time interval at inoculation levels of 10cfu/mL. Unlike the routine application of MALDI-TOF MS for identification of bacteria from solid media, this study proposes a cost-effective and time-saving detection scheme for direct identification of L. monocytogenes from broth cultures.This article is part of a Special Issue entitled: Trends in Microbial Proteomics. Globally, foodborne diseases are major causes of illness and fatalities in humans. Hence, there is a continual need for reliable and rapid means for pathogen detection from food samples. Recent applications of MALDI-TOF MS for diagnostic microbiology focused on detection of microbes from clinical specimens. However, the current study has emphasized its use as a tool for detecting the major foodborne pathogen, Listeria monocytogenes, directly from selective enrichment broths. This proof-of-concept study proposes a detection scheme that is more rapid and simple compared to conventional methods of Listeria detection. Very low levels of the pathogen could be identified from different food samples post-enrichment in selective enrichment broths. Use of this scheme will facilitate rapid and cost-effective testing for this important foodborne pathogen. © 2013.

Evaluation of paper gradient concentration strips for antifungal combination testing of Candida spp.

PubMed

Siopi, Maria; Siafakas, Nikolaos; Zerva, Loukia; Meletiadis, Joseph

2015-11-01

In vitro combination testing with broth microdilution chequerboard (CHEQ) method is widely used although it is time-consuming, cumbersome and difficult to apply in routine setting of clinical microbiology laboratory. A new gradient concentration paper strip method, the Liofilchem(®) MIC test strips (MTS), provides an alternative easy and fast method enabling the simultaneous diffusion of both drugs in combination. We therefore tested a polyene+azole and an azole+echinocandin combination against 18 Candida isolates with the CHEQ method based on EUCAST guidelines and the MTS method in research and routine settings. Fractional inhibitory concentration (FIC) indices were calculated after 24 and 48 h of incubation based on complete and prominent (FIC-2) growth inhibition endpoints. Reproducibility and agreement within 1 twofold dilution was assessed. The FICs of the two methods were correlated quantitatively with t-test and Pearson analysis and qualitatively with Chi-squared test. The reproducibility of the CHEQ and MTS method was 88-100% and their agreement was 80% with 62-77% of MTS FICs being higher than the corresponding CHEQ FICs. A statistically significant Pearson correlation (r = 0.86, P = 0.0003) and association (χ(2) = 17.05, df = 4, P = 0.002) was found between MTS FIC and CHEQ FIC-2 after 24 h. Categorical agreement was 63% with no very major or major errors. All MTS synergistic interactions were also synergistic with the CHEQ method. © 2015 Blackwell Verlag GmbH.

Occurrence of clostridia in commercially available curry roux.

PubMed

Fujisawa, T; Aikawa, K; Takahashi, T; Yamai, S; Ueda, S

2001-12-01

The occurrence of clostridia was investigated in a total of 60 commercially available curry roux samples. Clostridia were isolated from 37 (62%) samples, and Clostridium perfringens was isolated from 7 (12%) samples. The isolates of C. perfringens did not produce enterotoxin. The frequency of occurrence was higher by the enrichment broth culture detection method than by the agar plate or pouch method. These findings suggest that enrichment broth culture is necessary for the detection of clostridia.

Synergistic activity between Echinophora platyloba DC ethanolic extract and azole drugs against clinical isolates of Candida albicans from women suffering chronic recurrent vaginitis.

PubMed

Avijgan, M; Mahboubi, M; Moheb Nasab, M; Ahmadi Nia, E; Yousefi, H

2014-06-01

Candida albicans is one of the main causes of vaginitis, especially in women with recurrent episodes. The appearance of drug resistant C. albicans and adverse effects of chemical agents have raised interest in Echinophora platyloba as one of four native species in Traditional Persian-Iranian medicine. This study evaluates the antifungal activity of ethanolic extract from dried aerial parts of E. platyloba against 27 clinical isolates of C. albicans from women suffering chronic recurrent vaginitis by micro-broth dilution assay. The synergistic effect of azole drugs and E. platyloba ethanolic extract were also determined by disc diffusion method after determining the MIC90. The results of this study showed a potent synergistic effect of E. platyloba ethanolic extract and itraconazole (P<0.01) and fluconazole (P<0.001) but an antagonistic effect between E. platyloba ethanolic extract and clotrimazole and miconazole against clinical isolates of C. albicans. These results must be confirmed by clinical application and by further clinical studies. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Antibacterial properties of amino acid functionalized silver nanoparticles decorated on graphene oxide sheets

NASA Astrophysics Data System (ADS)

Chandraker, Kumudini; Nagwanshi, Rekha; Jadhav, S. K.; Ghosh, Kallol K.; Satnami, Manmohan L.

2017-06-01

Graphene oxide (GO) sheets decorated with amino acid L-cysteine (L-cys) functionalized silver nanoparticles (GO-L-cys-Ag) was synthesized by AgNO3, trisodium citrate, and NaBH4. GO-L-cys-Ag nanocomposite was characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-vis) absorption spectra, which demonstrated that a diameter of L-cys-AgNPs compactly deposited on GO. Antibacterial activity tests of GO-L-cys-Ag nanocomposite were carried out using Escherichia coli MTCC 1687 and Staphylococcus aureus MTCC 3160 as model strains of Gram-negative and Gram-positive bacteria, respectively. The effect of bactericide dosage on antibacterial activity of GO-L-cys-Ag nanocomposite was examined by plate count, well diffusion and broth dilution methods. Morphological observation of bacterial cells by scanning electron microscope (SEM) showed that GO-L-cys-Ag nanocomposite was more destructive to cell membrane of Escherichia coli than that of Staphylococcus aureus. The above technique establish that the bactericidal property of GO-L-cys-Ag nanocomposite with wide range of applications in biomedical science.

In vitro antibiotic susceptibility of Mycoplasma iguanae proposed sp. nov. isolated from vertebral lesions of green iguanas (Iguana iguana).

PubMed

Westfall, Megan E; Demcovitz, Dina L; Plourdé, Daisy R; Rotstein, David S; Brown, Daniel R

2006-06-01

Mycoplasma iguanae proposed species nova was isolated from vertebral abscesses of two feral iguanas (Iguana iguana) from Florida. Three strains were evaluated for sensitivity to a variety of antibiotics. The minimum inhibitory concentrations for M. iguanae, assessed by broth dilution methods, of clindamycin, doxycycline, enrofloxacin, oxytetracycline, and tylosin (all <1 microg/ml) were lower than those of chloramphenicol (32 micro/ml) and erythromycin (64 microg/ml). The profile was identical to that of Mycoplasma alligatoris, previously isolated from American alligators (Alligator mississippiensis). M. iguanae strain 2327T was subcultured without antibiotics to assess mycoplasmacidal activity. Clindamycin, doxycycline, oxytetracycline, and tylosin were bacteriostatic from 0.1 to 0.5 microg/ml, whereas enrofloxacin was bactericidal at 20 ng/ml. An enrofloxacin dosage of 5-10 mg/kg achieves peak plasma concentrations >1 microg/ml, with an elimination half-life of 6-20 hr, in alligators. Although concentrations achieved in the vertebrae by i.m. or i.v. injection are probably lower than those in plasma, these data suggest that enrofloxacin may be useful to treat M. iguanae mycoplasmosis in iguanas.

Synthesis of poly acrylic acid modified silver nanoparticles and their antimicrobial activities.

PubMed

Ni, Zhihui; Wang, Zhihua; Sun, Lei; Li, Binjie; Zhao, Yanbao

2014-08-01

Poly acrylic acid modified silver (Ag/PAA) nanoparticles (NPs) have been successfully synthesized in the aqueous solution by using tannic acid as a reductant. The structure, morphology and composition of Ag/PAA NPs were characterized by various techniques such as X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible absorption spectroscopy (UV-vis) and thermogravimetry analysis (TGA). The results show that PAA/Ag NPs have a quasi-ball shape with an average diameter of 10 nm and exhibit well crystalline, and the reaction conditions have some effect on products morphology and size distribution. In addition, the as-synthesized Ag/PAA NPs antimicrobial activities against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) were evaluated by the methods of broth dilution, cup diffusion, optical density (OD600) and electron microscopy observation. The as-synthesized Ag/PAA NPs exhibit excellent antibacterial activity. The antimicrobial mechanism may be attributed to the damaging of bacterial cell membrane and causing leakage of cytoplasm. Copyright © 2014 Elsevier B.V. All rights reserved.

New intracanal formulations containing doxycycline or chlorhexidine against Enterococcus faecalis.

PubMed

Silva, Ana Rita Marques da; Pinto, Shelon Cristina Souza; Santos, Elizabete Brasil dos; Santos, Fábio André dos; Farago, Paulo Vitor; Gomes, João Carlos; Pina-Vaz, Irene; Carvalho, Manuel Fontes

2014-01-01

The present study aims to evaluate the antimicrobial effect of two new intracanal preparations against E. faecalis. Thirty single-rooted human canine teeth were used. The crowns were removed and the roots were instrumented using a conventional technique. Three groups of ten teeth each were infected with 108 CFU/ ml of E. faecalis for 21 days. The root canals were flled with new intracanal medications containing 3% doxycycline hydrochloride (DX) or 2% chlorhexidine digluconate (CHX). Ten teeth received no medication (NM)-negative control. Microbial samples were obtained 21 days after contamination: 14 days under the effect of the intracanal medications and 7 days after replacing the medications by BHI broth. The samples were homogenized, diluted, seeded on BHI agar and incubated for 48h/36°C. The number of colony forming units (CFU/ml) was obtained and analyzed statistically. All intracanal dressings significantly reduced the number of bacterial cells in the root canal after 14 days with medication. After the period with 7 days with BHI broth, the CFU counts of E. faecalis remained at low values. However, the NM group showed a significant increase of CFU in this period to similar values of the initial contamination. 3% doxycycline hydrochloride gel and 2% CHX gel were effective to eliminate E. faecalis from the root canal system.

Identification of bacteria in blood culture broths using matrix-assisted laser desorption-ionization Sepsityper™ and time of flight mass spectrometry.

PubMed

Kok, Jen; Thomas, Lee C; Olma, Thomas; Chen, Sharon C A; Iredell, Jonathan R

2011-01-01

Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) is a novel method for the direct identification of bacteria from blood culture broths. We evaluate for the first time, the performance of the MALDI Sepsityper™ Kit and MS for the identification of bacteria compared to standard phenotypic methods using the manufacturer's specified bacterial identification criteria (spectral scores ≥1.700-1.999 and ≥2.000 indicated identification to genus and species level, respectively). Five hundred and seven positive blood culture broths were prospectively examined, of which 379 (74.8%; 358 monomicrobial, 21 polymicrobial) were identified by MALDI-TOF MS; 195 (100%) and 132 (67.7%) of 195 gram-positive; and 163 (100%) and 149 (91.4%) of 163 gram-negative organisms from monomicrobial blood cultures were correctly identified to genus and species level, respectively. Spectral scores <1.700 (no identification) were obtained in 128/507 (25.2%) positive blood culture broths, including 31.6% and 32.3% of gram-positive and polymicrobial blood cultures, respectively. Significantly more gram-negative organisms were identified compared to gram-positive organisms at species level (p<0.0001). Five blood cultures were misidentified, but at species level only; including four monomicrobial blood cultures with Streptococcus oralis/mitis that were misidentified as Streptococcus pneumoniae. Positive predictive values for the direct identification of both gram-positive and gram-negative bacteria from monomicrobial blood culture broths to genus level were 100%. A diagnostic algorithm for positive blood culture broths that incorporates gram staining and MALDI-TOF MS should identify the majority of pathogens, particularly to genus level.

Bioassay Guided Fractionation of an Anti-Methicillin-Resistant Staphylococcus aureus Flavonoid From Bromus inermis Leyss Inflorescences

PubMed Central

Aliahmadi, Atousa; Mirzajani, Fateme; Ghassempour, Alireza; Sonboli, Ali

2014-01-01

Background: Plants are considered as promising sources of new antibacterial agents as well as bioassay guided fractionation. Objectives: In the present work, the antibacterial properties, especially against methicillin-resistant Staphylococcus aureus (MRSA), of Bromus inermis inflorescence was studied, using the bioassay guided fractionation as well as the bio-autographic method. Materials and Methods: The plant organic extract was prepared via maceration in methanol, followed by the fractionation using n-hexane. The extracts were subjected for minimum inhibitory concentrations (MICs) against some human pathogenic bacteria via standard broth micro-dilution assay. Thereafter, a bio-autographical method was applied using the high performance thin layer chromatography (HPTLC) coupled with agar overlay assays for the primary characterization and identification of bioactive substance (s). Results: Through the bioassay guided fractionation method, the greatest antibacterial activities were related to the n-hexane extract. It was also revealed that the effective anti-MRSA agent of the assessed plant was a relatively polar substance with an MIC value of about 8 μg/mL against the tested MRSA strain (in comparison with the MIC value of 32 μg/mL for chloramphenicol). Conclusions: As a result of the full range UV-Vis scanning of the responsible band in the HPTLC experiments (200-700 nm), the flavonoid was the most imaginable natural compound. PMID:25741430

Effects of solutions treated with oxygen radicals in neutral pH region on inactivation of microorganism

NASA Astrophysics Data System (ADS)

Kobayashi, Tsuyoshi; Hashizume, Hiroshi; Ohta, Takayuki; Ishikawa, Kenji; Hori, Masaru; Ito, Masafumi

2015-09-01

The inactivation of microorganisms using nonequilbrium atmospheric pressure plasmas has been attracted much attention due to the low temperature processing and high speed treatment. In this study, we have inactivated E. coli suspended in solutions with neutral pH using an atmospheric-pressure oxygen radical source which can selectively supply electrically neutral oxygen radicals. E. coli cells were suspended with deionized distilled water (DDW) (pH = 6.8) or phosphate buffered saline (PBS) (pH = 7.4) or Citrate-Na buffer (pH = 6.5). The treated samples were diluted and spread on nutrient agar (Nutrient Broth). They were cultured at 37° C. The inactivation effects of oxygen radicals on those cells in solutions were evaluated by colony-counting method. O2 diluted by Ar gas were employed as a working gas for the radical source. The total gas flow rate and the gas mixture ratio of O2/(Ar + O2) were set at 5 slm and 0.6%, respectively. The distance between the radical exit and the suspension surface were set at 10 mm. As a result, the D values for DDW(pH = 6.8), PBS(pH = 7.4) and Citrate-Na buffer(pH = 6.5) were estimated to be 1.4 min, 0.9 min and 16.8 min respectively. The inactivation rates in DDW, PBS were significantly different from that in Citrate-Na buffer. This work was partly supported by JSPS KAKENHI Grant Number 26286072 and project for promoting Research Center in Meijo University.

In vitro susceptibility of spiroplasmas to heavy-metal salts.

PubMed

Whitmore, S C; Rissler, J F; Davis, R E

1983-01-01

The susceptibility of six spiroplasma strains to heavy-metal salt was characterized in terms of minimal inhibitory concentrations and minimal biocidal concentrations in broth tube dilution tests. The strains were most susceptible to mercuric chloride and silver nitrate; less susceptible to copper sulfate, cobalt chloride, lead nitrate, and cadmium sulfate; and least susceptible to nickel chloride and zinc sulfate. Spiroplasma citri strains Maroc R8A2 and C189 were the most susceptible to five of eight heavy-metal salts, and honeybee spiroplasma strain AS576 and Spiroplasma floricola strain 23-6 were generally the least susceptible. The difference between the minimal biocidal concentrations and the minimal inhibitory concentrations was greater for certain heavy-metal salts than for others.

Potato Dextrose Agar Antifungal Susceptibility Testing for Yeasts and Molds: Evaluation of Phosphate Effect on Antifungal Activity of CMT-3

PubMed Central

Liu, Yu; Tortora, George; Ryan, Maria E.; Lee, Hsi-Ming; Golub, Lorne M.

2002-01-01

The broth macrodilution method (BMM) for antifungal susceptibility testing, approved by the National Committee for Clinical Laboratory Standards (NCCLS), was found to have deficiencies in testing of the antifungal activity of a new type of antifungal agent, a nonantibacterial chemically modified tetracycline (CMT-3). The high content of phosphate in the medium was found to greatly increase the MICs of CMT-3. To avoid the interference of phosphate in the test, a new method using potato dextrose agar (PDA) as a culture medium was developed. Eight strains of fungi, including five American Type Culture Collection strains and three clinical isolates, were used to determine the MICs of amphotericin B and itraconazole with both the BMM and the PDA methods. The MICs of the two antifungal agents determined with the PDA method showed 99% agreement with those determined with the BMM method within 1 log2 dilution. Similarly, the overall reproducibility of the MICs with the PDA method was above 97%. Three other antifungal agents, fluconazole, ketoconazole, and CMT-3, were also tested in parallel against yeasts and molds with both the BMM and the PDA methods. The MICs of fluconazole and ketoconazole determined with the PDA method showed 100% agreement within 1 log2 dilution of those obtained with the BMM method. However, the MICs of CMT-3 determined with the BMM method were as high as 128 times those determined with the PDA method. The effect of phosphate on the antifungal activity of CMT-3 was evaluated by adding Na2HPO4 to PDA in the new method. It was found that the MIC of CMT-3 against a Penicillium sp. increased from 0.5 μg/ml (control) to 2.0 μg/ml when the added phosphate was used at a concentration of 0.8 mg/ml, indicating a strong interference of Na2HPO4 with the antifungal activity of CMT-3. Except for fluconazole, all the other antifungal agents demonstrated clear end points among the yeasts and molds tested. Nevertheless, with its high reproducibility, good agreement with NCCLS proposed MIC ranges, and lack of interference of phosphate, the PDA method shows promise as a useful assay for antifungal susceptibility testing and screening for new antifungal agents, especially for drugs that may be affected by high (supraphysiologic) phosphate concentrations. PMID:11959582

Aqueous penetration and biological activity of moxifloxacin 0.5% ophthalmic solution and gatifloxacin 0.3% solution in cataract surgery patients.

PubMed

Kim, Dianne H; Stark, Walter J; O'Brien, Terrence P; Dick, James D

2005-11-01

To measure the achievable perioperative aqueous concentration of the commercially available topically administered fourth generation fluoroquinolones, moxifloxacin 0.5% ophthalmic solution, and gatifloxacin 0.3% ophthalmic solution, and to correlate this concentration with the agents' biological efficacy in the aqueous humor of patients undergoing routine cataract surgery. Prospective, randomized, parallel, double-masked, clinical trial. Fifty patients undergoing cataract extraction. Patients (n = 25) were given perioperative topical moxifloxacin 0.5% or topical gatifloxacin 0.3% (n = 25). One drop of antibiotic was administered every 10 minutes for 4 doses beginning 1 hour prior to surgery. Aqueous humor was sampled via paracentesis and antibiotic concentrations were determined using validated high performance liquid chromatography (HPLC) procedures. Dilution analyses were performed to determine the biological efficacy of the agents in the aqueous against Staphylococcus epidermidis, the most common cause of postcataract endophthalmitis. Aqueous humor antibiotic concentrations were measured using HPLC and microdilution bioassay techniques. Biological activity was measured as minimal inhibitory dilution and minimal bactericidal dilution. Aqueous humor concentrations for moxifloxacin via HPLC analysis were 1.80 (+/-1.21) microg/ml, whereas those for gatifloxacin were 0.48 (+/-0.34) microg/ml. This 3.8-fold difference in aqueous humor antibiotic concentrations was statistically significant (P = 0.00003). Similarly, the biological dilution analysis of the aqueous humor samples showed that moxifloxacin attained an estimated activity of 2.1 microg/ml, whereas the gatifloxacin activity was approximately 0.4 mug/ml, which represented a 4.9-fold difference. This study demonstrated that after topically administered perioperative antibiotics with cataract surgery, moxifloxacin 0.5% ophthalmic solution achieved a statistically significantly higher concentration in aqueous humor compared with gatifloxacin (P = 0.00003). Results from the broth dilution analysis showed that moxifloxacin 0.5% was biologically more active against S. epidermidis than gatifloxacin 0.3% in aqueous humor after topical application. There were no adverse events reported, and incision wounds healed quickly and as expected.

Comparison of Meropenem MICs and Susceptibilities for Carbapenemase-Producing Klebsiella pneumoniae Isolates by Various Testing Methods▿

PubMed Central

Bulik, Catharine C.; Fauntleroy, Kathy A.; Jenkins, Stephen G.; Abuali, Mayssa; LaBombardi, Vincent J.; Nicolau, David P.; Kuti, Joseph L.

2010-01-01

We describe the levels of agreement between broth microdilution, Etest, Vitek 2, Sensititre, and MicroScan methods to accurately define the meropenem MIC and categorical interpretation of susceptibility against carbapenemase-producing Klebsiella pneumoniae (KPC). A total of 46 clinical K. pneumoniae isolates with KPC genotypes, all modified Hodge test and blaKPC positive, collected from two hospitals in NY were included. Results obtained by each method were compared with those from broth microdilution (the reference method), and agreement was assessed based on MICs and Clinical Laboratory Standards Institute (CLSI) interpretative criteria using 2010 susceptibility breakpoints. Based on broth microdilution, 0%, 2.2%, and 97.8% of the KPC isolates were classified as susceptible, intermediate, and resistant to meropenem, respectively. Results from MicroScan demonstrated the most agreement with those from broth microdilution, with 95.6% agreement based on the MIC and 2.2% classified as minor errors, and no major or very major errors. Etest demonstrated 82.6% agreement with broth microdilution MICs, a very major error rate of 2.2%, and a minor error rate of 2.2%. Vitek 2 MIC agreement was 30.4%, with a 23.9% very major error rate and a 39.1% minor error rate. Sensititre demonstrated MIC agreement for 26.1% of isolates, with a 3% very major error rate and a 26.1% minor error rate. Application of FDA breakpoints had little effect on minor error rates but increased very major error rates to 58.7% for Vitek 2 and Sensititre. Meropenem MIC results and categorical interpretations for carbapenemase-producing K. pneumoniae differ by methodology. Confirmation of testing results is encouraged when an accurate MIC is required for antibiotic dosing optimization. PMID:20484603

A Rapid, Presumptive Procedure for the Detection of Salmonella in Foods and Food Ingredients

PubMed Central

Hoben, D. A.; Ashton, D. H.; Peterson, A. C.

1973-01-01

A rapid detection procedure was developed in which a lysine-iron-cystine-neutral red (LICNR) broth medium, originally described by Hargrove et al. in 1971, was modified and used to detect the presence of viable Salmonella organisms in a variety of foods, food ingredients, and feed materials by using a two-step enrichment technique. Tetrathionate broth was used to enrich samples with incubation at 41 C for 20 hr, followed by transfer to LICNR broth and incubation at 37 C for 24 hr for further enrichment and for the detection of Salmonella organisms by color change. One hundred ten samples representing 18 different sample types were evaluated for the presence of viable Salmonella. Ninety-four percent of the samples found to be presumptive positive by this method were confirmed as positive by a culture method. Fluorescent-antibody results also compared closely. A second study was conducted under quality-control laboratory conditions by using procedures currently employed for Salmonella detection. One hundred forty-three samples representing 19 different sample types were evaluated for the presence of viable Salmonella. No false negatives were observed with the rapid-detection method. The usefulness of the LICNR broth procedure as a screening technique to eliminate negative samples rapidly and to identify presumptive positive samples for the presence of viable Salmonella organisms was established in this laboratory. PMID:4568884

Effect of United States buckwheat honey on antibiotic-resistant hospital acquired pathogens

PubMed Central

Hammond, Eric Nee-Armah; Duster, Megan; Musuuza, Jackson Ssentalo; Safdar, Nasia

2016-01-01

Introduction Due to an upsurge in antibiotic-resistant infections and lack of therapeutic options, new approaches are needed for treatment. Honey may be one such potential therapeutic option. We investigated the susceptibility of hospital acquired pathogens to four honeys from Wisconsin, United States, and then determined if the antibacterial effect of each honey against these pathogens is primarily due to the high sugar content. Methods Thirteen pathogens including: four Clostridium difficile, two Methicillin-resistant Staphylococcus aureus, two Pseudomonas aeruginosa, one Methicillin-Susceptible Staphylococcus aureus, two Vancomycin-resistance Enterococcus, one Enterococcus faecalis and one Klebsiella pneumoniae were exposed to 1-50% (w/v) four Wisconsin honeys and Artificial honey to determine their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the broth dilution method. Results Buckwheat honey predominantly exhibited a bactericidal mode of action against the tested pathogens, and this varied with each pathogen. C. difficile isolates were more sensitive to the Wisconsin buckwheat honey as compared to the other pathogens. Artificial honey at 50% (w/v) failed to kill any of the pathogens. The high sugar content of Wisconsin buckwheat honey is not the only factor responsible for its bactericidal activity. Conclusion Wisconsin buckwheat honey has the potential to be an important addition to therapeutic armamentarium against resistant pathogens and should be investigated further. PMID:28292167

Amino acid analysis in mammalian cell culture media containing serum and high glucose concentrations by anion exchange chromatography and integrated pulsed amperometric detection.

PubMed

Genzel, Yvonne; König, Susanne; Reichl, Udo

2004-12-01

The direct separation detection of amino acids by anion exchange chromatography with integrated pulsed amperometric detection was optimized for the analysis of typical mammalian cell culture broth samples. Existing gradient elution conditions were adapted, considering the additions of peptone (2 g/L) and 10 vol% fetal calf serum to the medium as well as changing concentrations of glucose from 5.5 g/L up to complete consumption. Samples had to be analyzed in two dilutions with water (1:33.3 and 1:200) due to the strongly varying amino acid concentrations in the samples as a result of the medium composition and cell metabolism. The method was validated in a linear working range for the most common amino acids (2.5-7.5 and 1.25-3.75 microM for cystine/cysteine with 15 microl injection volume). The relative standard deviation of the method for all amino acids was less than 5%, with detection limits of less than 0.6 microM and quantitation limits of less than 1.6 microM. As an example, data for the amino acid composition of different media used for the production of inactivated influenza vaccines in cell culture are shown.

In vitro and in vivo activities of posaconazole and amphotericin B in a murine invasive infection by Mucor circinelloides: poor efficacy of posaconazole.

PubMed

Salas, Valentina; Pastor, F Javier; Calvo, Enrique; Alvarez, Eduardo; Sutton, Deanna A; Mayayo, Emilio; Fothergill, Anette W; Rinaldi, Michael G; Guarro, Josep

2012-05-01

The in vitro susceptibility of 17 strains of Mucor circinelloides to amphotericin B and posaconazole was ascertained by using broth microdilution and disk diffusion methods and by determining the minimal fungicidal concentration (MFC). We evaluated the efficacy of posaconazole at 40 mg/kg of body weight/day and amphotericin B at 0.8 mg/kg/day in a neutropenic murine model of disseminated infection by M. circinelloides by using 6 different strains tested previously in vitro. In general, most of the posaconazole MICs were within the range of susceptibility or intermediate susceptibility, while the small inhibition zone diameters (IZDs) were indicative of nonsusceptibility for all isolates tested. The MFCs were ≥ 3 dilutions higher than the corresponding MICs. In contrast, amphotericin B showed good activity against all of the strains tested regardless of the method used. The in vivo studies demonstrated that amphotericin B was effective in prolonging survival and reducing the fungal load. Posaconazole showed poor in vivo efficacy with no correlation with the MIC values. The results suggested that posaconazole should be used with caution in the treatment of infections caused by Mucor circinelloides or by strains of Mucor not identified to the species level.

In vitro antibacterial activity of ethanolic extract of Morus alba leaf against periodontal pathogens.

PubMed

Gunjal, Shilpa; Ankola, Anil V; Bhat, Kishore

2015-01-01

Antibiotic resistance is a major problem with inadvertent usage. Thus, there is a need to search for new antimicrobial agents of herbal origin to combat antibiotic resistance. One such plant is Morus alba which has a long history of medicinal use in traditional Chinese medicine. To compare the antibacterial activity of ethanolic extract of M. alba leaves with chlorhexidine gluconate against Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythia. Experimental in vitro study. Crude extract from the leaves of M. alba were prepared by Soxhlet extraction method by using ethanol as a solvent. Minimum inhibitory concentration (MIC) of the extract was assessed against A. actinomycetemcomitans, P. gingivalis and T. forsythia, and compared with that of chlorhexidine gluconate by broth dilution method. P. gingivalis was the most sensitive organism against the M. alba extract with an MIC value of 1.95 mg/ml; while T. forsythia and P. gingivalis both were most sensitive organisms against chlorhexidine gluconate with MIC values of 0.00781 mg/ml. M. alba possess good antibacterial activity against A. actinomycetemcomitans, P. gingivalis and T. forsythia and thus would be beneficial for the prevention and treatment of periodontal disease. However, chlorhexidine gluconate was found to be more effective when compared to M. alba.

Drinking water test methods in crisis-afflicted areas: comparison of methods under field conditions.

PubMed

Merle, Roswitha; Bleul, Ingo; Schulenburg, Jörg; Kreienbrock, Lothar; Klein, Günter

2011-11-01

To simplify the testing of drinking water in crisis-afflicted areas (as in Kosovo in 2007), rapid test methods were compared with the standard test. For Escherichia coli and coliform pathogens, rapid tests were made available: Colilert(®)-18, P/A test with 4-methylumbelliferyl-β-D-glucoronid, and m-Endo Broth. Biochemical differentiation was carried out by Enterotube™ II. Enterococci were determined following the standard ISO test and by means of Enterolert™. Four hundred ninety-nine water samples were tested for E. coli and coliforms using four methods. Following the standard method, 20.8% (n=104) of the samples contained E. coli, whereas the rapid tests detected between 19.6% (m-Endo Broth, 92.0% concordance) and 20.0% (concordance: 93.6% Colilert-18 and 94.8% P/A-test) positive samples. Regarding coliforms, the percentage of concordant results ranged from 98.4% (P/A-test) to 99.0% (Colilert-18). Colilert-18 and m-Endo Broth detected even more positive samples than the standard method did. Enterococci were detected in 93 of 573 samples by the standard method, but in 92 samples by Enterolert (concordance: 99.5%). Considering the high-quality equipment and time requirements of the standard method, the use of rapid tests in crisis-afflicted areas is sufficiently reliable.

Isothermal microcalorimetry for antifungal susceptibility testing of Mucorales, Fusarium spp., and Scedosporium spp.

PubMed

Furustrand Tafin, Ulrika; Meis, Jacques F; Trampuz, Andrej

2012-08-01

We evaluated isothermal microcalorimetry for real-time susceptibility testing of non-Aspergillus molds. MIC and minimal effective concentration (MEC) values of Mucorales (n = 4), Fusarium spp. (n = 4), and Scedosporium spp. (n = 4) were determined by microbroth dilution according to the Clinical Laboratory Standard Institute M38-A2 guidelines. Heat production of molds was measured at 37 °C in Sabouraud dextrose broth inoculated with 2.5 × 10(4) spores/mL in the presence of amphotericin B, voriconazole, posaconazole, caspofungin, and anidulafungin. As determined by microcalorimetry, amphotericin B was the most active agent against Mucorales (MHIC 0.06-0.125 μg/mL) and Fusarium spp. (MHIC 1-4 μg/mL), whereas voriconazole was the most active agent against Scedosporium spp. (MHIC 0.25 to 8 μg/mL). The percentage of agreement (within one 2-fold dilution) between the MHIC and MIC (or MEC) was 67%, 92%, 75%, and 83% for amphotericin B, voriconazole, posaconazole, and caspofungin, respectively. Microcalorimetry provides additional information on timing of antifungal activity, enabling further investigation of drug-mold and drug-drug interaction, and optimization of antifungal treatment. Copyright © 2012 Elsevier Inc. All rights reserved.

Antibacterial, antifungal and cytotoxic evaluation of some new quinazolinone derivatives

PubMed Central

Hassanzadeh, F.; Jafari, E.; Hakimelahi, G.H.; Khajouei, M. Rahmani; Jalali, M.; Khodarahmi, G.A.

2012-01-01

Quinazolinone ring system is renown because of its wide spectrum of pharmacological activities due to various substitutions on this ring system. In this study, the minimum inhibitory concentration of the synthesized compounds in our laboratory was determined by micro dilution Alamar Blue® Assay against six strains of bacteria (three Gram-positive and three Gram-negative) and three strains of fungi. Following a broth micro dilution minimum inhibitory concentration (MIC) test, Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) tests were performed. Cytotoxic effects of the compounds were measured using the MTT colorimetric assay on HeLa cell line. Results of antimicrobial screening showed that compounds had better bacteriostatic activity against Gram-negative bacteria. Results from MBC revealed that these compounds had more significant bacteriostatic than bactericidal activities. Nearly all screened compounds showed good activity against C. albicans and A. niger. Results from MFC indicated that these compounds had better fungistatic rather than fungicidal activities. The synthesized target molecules were found to exhibit different cytotoxicity in the range of 10 to 100 μM on HeLa cell line. Compounds 6 and 7 exhibited acceptable cytotoxicity approximately 50% at 10 μM concentration. PMID:23181085

Production of a COX-2 inhibitor, 2,4,5-trimethoxybenzaldehyde, with submerged cultured Antrodia camphorata.

PubMed

Chen, C-C; Chyau, C-C; Hseu, T-H

2007-04-01

To investigate the active ingredient in fruiting bodies and to produce it with cultured mycelium in Antrodia camphorata (BCRC 35398). The volatile components from the fruiting bodies, the liquid cultured broth of A. camphorata and Cinnamomum kanehirae wood were separately isolated by steam distillation-solvent extraction and identified by gas chromatography-mass spectrometry. In the fruiting bodies, a COX-2 inhibitor 2,4,5-trimethoxybenzaldehyde (TMBA) was found to be the most abundant constituent, but was totally absent in its cultured broth and its natural host, C. kanehirae wood. On feeding with the acid-digested sawdust of C. kanehirae wood or vanillin to the broth for culture, TMBA was produced in both cultured broths. The TMBA identified in fruiting bodies was an active ingredient whose functions consisted with the reported experiences of this mushroom. Feeding vanillin to culture broth could produce TMBA containing mycelium product like its fruiting bodies did. This study found an active ingredient in fruiting bodies of A. camphorata and elucidated this compound derived from digested sawdust of C. kanehirae wood. A feasible method was also developed to produce TMBA containing mycelium by feeding vanillin.

Multicenter Evaluation of the Cepheid Xpert Methicillin-Resistant Staphylococcus aureus (MRSA) Test as a Rapid Screening Method for Detection of MRSA in Nares▿

PubMed Central

Wolk, D. M.; Picton, E.; Johnson, D.; Davis, T.; Pancholi, P.; Ginocchio, C. C.; Finegold, S.; Welch, D. F.; de Boer, M.; Fuller, D.; Solomon, M. C.; Rogers, B.; Mehta, M. S.; Peterson, L. R.

2009-01-01

The first U.S. multicenter clinical trial to assess the performance of the Cepheid Xpert MRSA assay (Xpert MRSA) was conducted. The assay is a qualitative test designed for the rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) directly from nares swabs. This novel test combines integrated nucleic acid extraction and automated real-time PCR for the detection of a MRSA-specific signature sequence. A total of 1,077 nares specimens were collected from seven geographically distinct health care sites across the United States with prevalence rates ranging from 5.2% to 44%. Nares specimens were tested by (i) the Xpert MRSA assay, (ii) direct culture on CHROMagar MRSA medium (direct CM culture), and (iii) broth-enriched culture (Trypticase soy broth with 6.5% sodium chloride) followed by plating onto CHROMagar MRSA medium (broth-enriched CM culture). When direct CM culture was designated the reference method, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the Xpert MRSA assay were 94.3%, 93.2%, 73.0%, and 98.8%, respectively. When broth-enriched CM culture was used as the reference method, the clinical sensitivity, specificity, PPV, and NPV of the Xpert MRSA assay were 86.3%, 94.9%, 80.5%, and 96.6%, respectively. The BD GeneOhm MRSA (BDGO) assay was performed as a comparative molecular method. No statistical performance differences were observed between the Xpert MRSA and BDGO assays when they were compared to culture methods. From this large-scale, multicenter clinical comparison, we conclude that the Xpert MRSA assay is a simple, rapid, and accurate method for performing active surveillance for MRSA in a variety of health care populations. PMID:19129414

Performance of the AOAC use-dilution method with targeted modifications: collaborative study.

PubMed

Tomasino, Stephen F; Parker, Albert E; Hamilton, Martin A; Hamilton, Gordon C

2012-01-01

The U.S. Environmental Protection Agency (EPA), in collaboration with an industry work group, spearheaded a collaborative study designed to further enhance the AOAC use-dilution method (UDM). Based on feedback from laboratories that routinely conduct the UDM, improvements to the test culture preparation steps were prioritized. A set of modifications, largely based on culturing the test microbes on agar as specified in the AOAC hard surface carrier test method, were evaluated in a five-laboratory trial. The modifications targeted the preparation of the Pseudomonas aeruginosa test culture due to the difficulty in separating the pellicle from the broth in the current UDM. The proposed modifications (i.e., the modified UDM) were compared to the current UDM methodology for P. aeruginosa and Staphylococcus aureus. Salmonella choleraesuis was not included in the study. The goal was to determine if the modifications reduced method variability. Three efficacy response variables were statistically analyzed: the number of positive carriers, the log reduction, and the pass/fail outcome. The scope of the collaborative study was limited to testing one liquid disinfectant (an EPA-registered quaternary ammonium product) at two levels of presumed product efficacies, high and low. Test conditions included use of 400 ppm hard water as the product diluent and a 5% organic soil load (horse serum) added to the inoculum. Unfortunately, the study failed to support the adoption of the major modification (use of an agar-based approach to grow the test cultures) based on an analysis of method's variability. The repeatability and reproducibility standard deviations for the modified method were equal to or greater than those for the current method across the various test variables. However, the authors propose retaining the frozen stock preparation step of the modified method, and based on the statistical equivalency of the control log densities, support its adoption as a procedural change to the current UDM. The current UDM displayed acceptable responsiveness to changes in product efficacy; acceptable repeatability across multiple tests in each laboratory for the control counts and log reductions; and acceptable reproducibility across multiple laboratories for the control log density values and log reductions. Although the data do not support the adoption of all modifications, the UDM collaborative study data are valuable for assessing sources of method variability and a reassessment of the performance standard for the UDM.

Comparison of Minocycline Susceptibility Testing Methods for Carbapenem-Resistant Acinetobacter baumannii.

PubMed

Wang, Peng; Bowler, Sarah L; Kantz, Serena F; Mettus, Roberta T; Guo, Yan; McElheny, Christi L; Doi, Yohei

2016-12-01

Treatment options for infections due to carbapenem-resistant Acinetobacter baumannii are extremely limited. Minocycline is a semisynthetic tetracycline derivative with activity against this pathogen. This study compared susceptibility testing methods that are used in clinical microbiology laboratories (Etest, disk diffusion, and Sensititre broth microdilution methods) for testing of minocycline, tigecycline, and doxycycline against 107 carbapenem-resistant A. baumannii clinical isolates. Susceptibility rates determined with the standard broth microdilution method using cation-adjusted Mueller-Hinton (MH) broth were 77.6% for minocycline and 29% for doxycycline, and 92.5% of isolates had tigecycline MICs of ≤2 μg/ml. Using MH agar from BD and Oxoid, susceptibility rates determined with the Etest method were 67.3% and 52.3% for minocycline, 21.5% and 18.7% for doxycycline, and 71% and 29.9% for tigecycline, respectively. With the disk diffusion method using MH agar from BD and Oxoid, susceptibility rates were 82.2% and 72.9% for minocycline and 34.6% and 34.6% for doxycycline, respectively, and rates of MICs of ≤2 μg/ml were 46.7% and 23.4% for tigecycline. In comparison with the standard broth microdilution results, very major rates were low (∼2.8%) for all three drugs across the methods, but major error rates were higher (∼5.6%), especially with the Etest method. For minocycline, minor error rates ranged from 14% to 37.4%. For tigecycline, minor error rates ranged from 6.5% to 69.2%. The majority of minor errors were due to susceptible results being reported as intermediate. For minocycline susceptibility testing of carbapenem-resistant A. baumannii strains, very major errors are rare, but major and minor errors overcalling strains as intermediate or resistant occur frequently with susceptibility testing methods that are feasible in clinical laboratories. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Removing Bacillus subtilis from fermentation broth using alumina nanoparticles.

PubMed

Mu, Dashuai; Mu, Xin; Xu, Zhenxing; Du, Zongjun; Chen, Guanjun

2015-12-01

In this study, an efficient separation technology using Al2O3 nanoparticles (NPs) was developed for removing Bacillus subtilis from fermentation broth. The dosage of alumina nanoparticles used for separating B. subtilis increased during the culture process and remained stable in the stationary phase of the culture process. The pH of the culture-broth was also investigated for its effects on flocculation efficiency, and showed an acidic pH could enhance the flocculation efficiency. The attachment mechanisms of Al2O3 NPs to the B. subtilis surface were investigated, and the zeta potential analysis showed that Al2O3 NPs could attach to B. subtilis via electrostatic attachment. Finally, the metabolite content and the antibacterial effect of the fermentation supernatants were detected and did not significantly differ between alumina nanoparticle separation and centrifugation separation. Together, these results indicate a great potential for a highly efficient and economical method for removing B. subtilis from fermentation broth using alumina nanoparticles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Separation and purification of γ-aminobutyric acid from fermentation broth by flocculation and chromatographic methodologies.

PubMed

Gao, Qiang; Duan, Qiang; Wang, Depei; Zhang, Yunze; Zheng, Chunyang

2013-02-27

To date, the multifunctional γ-aminobutyric acid (GABA) is mainly produced by microbial fermentation in industry. The purpose of this study was to find an effective method for separation and purification of 31.2 g/L initial GABA from the fermentation broth of Enterococcus raffinosus TCCC11660. To remove the impurities from fermentation broth, flocculation pretreatment using chitosan and sodium alginate was first implemented to facilitate subsequent filtration. Ultrafiltration followed two discontinuous diafiltration steps to effectively remove proteins and macromolecular pigments, and the resulting permeate was further decolored by DA201-CII resin at a high decoloration ratio and GABA recovery. Subsequently, ion exchange chromatography (IEC) with Amberlite 200C resin and gradient elution were applied for GABA separation from glutamate and arginine. Finally, GABA crystals of 99.1% purity were prepared via warm ethanol precipitation twice. Overall, our results reveal that the successive process including flocculation, filtration, ultrafiltration, decoloration, IEC, and crystallization is promising for scale-up GABA extraction from fermentation broth.

Sugaring-out extraction of acetoin from fermentation broth by coupling with fermentation.

PubMed

Dai, Jian-Ying; Ma, Lin-Hui; Wang, Zhuang-Fei; Guan, Wen-Tian; Xiu, Zhi-Long

2017-03-01

Acetoin is a natural flavor and an important bio-based chemical which could be separated from fermentation broth by solvent extraction, salting-out extraction or recovered in the form of derivatives. In this work, a novel method named as sugaring-out extraction coupled with fermentation was tried in the acetoin production by Bacillus subtilis DL01. The effects of six solvents on bacterial growth and the distribution of acetoin and glucose in different solvent-glucose systems were explored. The operation parameters such as standing time, glucose concentration, and volume ratio of ethyl acetate to fermentation broth were determined. In a system composed of fermentation broth, glucose (100%, m/v) and two-fold volume of ethyl acetate, nearly 100% glucose was distributed into bottom phase, and 61.2% acetoin into top phase without coloring matters and organic acids. The top phase was treated by vacuum distillation to remove solvent and purify acetoin, while the bottom phase was used as carbon source to produce acetoin in the next batch of fermentation.

Direct detection of methicillin resistance in Staphylococcus aureus in blood culture broth by use of a penicillin binding protein 2a latex agglutination test.

PubMed

Qian, Qinfang; Venkataraman, Lata; Kirby, James E; Gold, Howard S; Yamazumi, Toshiaki

2010-04-01

We studied the utility of performing a penicillin binding protein 2a latex agglutination (PBP-LA) assay directly on Bactec blood culture broth samples containing Staphylococcus aureus to rapidly detect methicillin resistance. The sensitivity, specificity, positive predictive value, and negative predictive value of this method were 94.1%, 97.5%, 98%, and 92.9%, respectively.

Antimicrobial effects of marine algal extracts and cyanobacterial pure compounds against five foodborne pathogens.

PubMed

Dussault, Dominic; Vu, Khanh Dang; Vansach, Tifanie; Horgen, F David; Lacroix, Monique

2016-05-15

The marine environment is a proven source of structurally complex and biologically active compounds. In this study, the antimicrobial effects of a small collection of marine-derived extracts and isolates, were evaluated against 5 foodborne pathogens using a broth dilution assay. Results demonstrated that algal extracts from Padina and Ulva species and cyanobacterial compounds antillatoxin B, laxaphycins A, B and B3, isomalyngamide A, and malyngamides C, I and J showed antimicrobial activity against Gram positive foodborne pathogens (Listeria monocytogenes, Bacillus cereus and Staphylococcus aureus) at low concentrations (⩽ 500 μg/ml). None of the algal extracts or cyanobacterial isolates had antibacterial activity against Gram negative bacteria (Escherichia coli and Salmonella enterica serovar Typhimurium). Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of Coliform Source on Evaluation of Membrane Filters

PubMed Central

Brodsky, M. H.; Schiemann, D. A.

1975-01-01

Four brands of membrane filters were examined for total and fecal coliform recovery performance by two experimental approaches. Using diluted EC broth cultures of water samples, Johns-Manville filters were superior to Sartorius filters for fecal coliform but equivalent for total coliform recovery. Using river water samples, Johns-Manville filters were superior to Sartorius filters for total coliform but equivalent for fecal coliform recovery. No differences were observed between Johns-Manville and Millipore or Millipore and Sartorius filters for total or fecal coliform recoveries using either approach, nor was any difference observed between Millipore and Gelman filters for fecal coliform recovery from river water samples. These results indicate that the source of the coliform bacteria has an important influence on the conclusions of membrane filter evaluation studies. PMID:1106318

Wet-plate culture studies of Penicillium sp. PT95 and Q1 for mass production of sclerotia.

PubMed

Zhao, Wen-Jing; An, Cui-Hong; Han, Jian-Rong

2014-04-01

Penicillium sp. PT95 and Q1 strains were able to form abundant orange, sand-shaped sclerotia in which carotenoids were accumulated. To determine the potential availability of the wet-plate method for mass production of sclerotia, nine kinds of liquid media were used culture the PT95 and Q1 strains. The results of the wet-plate culture showed that on 25% glycerol nitrate broth medium, the growth of both strains was relatively slow, and no sclerotia were found. Q1 strain cultured on Czapek's yeast extract broth medium could not form sclerotia. On other media, both strains could form sclerotia. For PT95 strain, the highest sclerotial biomass (380 mg plate(-1) ) and carotenoids yield (20.88 µg plate(-1) ) could be obtained on Czapek's yeast extract broth and Georgiou's liquid medium, respectively. For Q1 strain, malt extract broth medium gave the highest sclerotial biomass (340 mg plate(-1) ) and omitting iron Joham's liquid medium gave the highest carotenoids yield (18.29 µg plate(-1) ). The results from this study suggest the potential usage of wet-plate method in the mass production of sclerotia of the PT95 and Q1 strains. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antibacterial properties of root canal lubricants: a comparison with commonly used irrigants.

PubMed

Wong, Samantha; Mundy, Lance; Chandler, Nicholas; Upritchard, Jenine; Purton, David; Tompkins, Geoffrey

2014-12-01

The aim was to assess in vitro the antibacterial activity of 10 root canal lubricants. K-Y Jelly personal lubricant, RC-Prep, File-Eze, File-Rite, EndoPrep Gel, Endosure Prep Crème 15%, Prep-Rite, Glyde, SlickGel ES and Alpha Glide were selected and compared in their antimicrobial properties to seven irrigants. Serial dilutions of each agent in tryptic soy broth were inoculated with either Enterococcus faecalis or Pseudomonas aeruginosa and incubated at 37C for 24 h. During incubation bacterial growth was measured by optical density (A(600)), and samples removed for cultivation on tryptic soy broth agar. Against both test bacteria after 1 h incubation, six lubricants recorded minimum bactericidal concentrations ranging from 1/10 to 1/80, whereas the inhibitory activity of the irrigants ranged from 1/20 to 1/640. Under these conditions, several lubricants exhibited antimicrobial activity comparable with some irrigants. Three irrigants, Consepsis (containing chlorhexidine), Endosure EDTA/C (containing cetrimide) and EndoPrep Solution (containing cetrimide), showed superior antibacterial action to lubricants against both species. The irrigants containing ethylenediamine tetraacetic acid and cetrimide were the most effective against both bacterial species at all time intervals. Antimicrobial activity of the lubricants did not correlate to pH values, which ranged from 2.9 to 10.3. Root canal lubricants have antibacterial properties that may help to disinfect canals. © 2014 Australian Society of Endodontology.

Cell viability of Candida albicans against the antifungal activity of thymol.

PubMed

de Vasconcelos, Laís César; Sampaio, Fabio Correia; Albuquerque, Allan de Jesus dos Reis; Vasconcelos, Laurylene César de Souza

2014-01-01

Candida albicans is a commensal fungus, but circumstantially it may cause superficial infections of the mucous membranes, such as denture stomatitis, when a biofilm is formed on the surface of dental prostheses. This study evaluated the cell viability of C. albicans biofilms against the antifungal activity of thymol when compared with miconazole, by the fluorescence imaging using SYTO 9 and propidium iodide dyes, and counting of colony forming units. C. albicans standard strains (ATCC 11006) were used. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of drugs were determined by broth microdilution tests and the inoculum was standardized to match 0.5 on the McFarland scale (106 cfu/mL). Biofilms were grown on the surface of acrylic resin disks in parallel flow chambers from Sabouraud broth supplemented with 10% dextrose. For counting of colony forming units, the fungal solution was sequentially diluted and plated in Sabouraud dextrose agar. Data were analyzed using two-way ANOVA and Tukey's test (a=5%). Biofilms treated with thymol and miconazole presented low numbers of viable cells at the evaluated exposure times. There was statistically significant difference (p<0.05) when compared with control, and the mean value of the exposure times between miconazole and thymol did not differ significantly (p>0.05). In conclusion, both drugs have similar efficiency as antifungal agents against biofilms of C. albicans formed on acrylic surfaces.

Bacillus methylotrophicus Strain NKG-1, Isolated from Changbai Mountain, China, Has Potential Applications as a Biofertilizer or Biocontrol Agent.

PubMed

Ge, Beibei; Liu, Binghua; Nwet, Thinn Thinn; Zhao, Wenjun; Shi, Liming; Zhang, Kecheng

2016-01-01

Chemical pesticides are widely used in agriculture, which endangers both environmental health and food safety. Biocontrol is an environmentally-friendly and cost-effective green technique in environmental protection and agricultural production; it generally uses selected bioresources, including beneficial microorganisms. We isolated a novel bacterial strain (NKG-1) from the rare dormant volcanic soils of Changbai Mountain in China's Jilin Province. The strain was identified as Bacillus methylotrophicus using morphological, biochemical, physiological, and phylogenetic 16S rDNA sequencing data. This strain was able to suppress mycelial growth and conidial germination of numerous plant pathogenic fungi on solid media. A greenhouse experiment showed that application of NKG-1 fermentation broth prior to inoculation of Botrytis cinerea, the cause of gray tomato mold, inhibited growth of the mold by 60%. Furthermore, application of a 100× dilution of NKG-1 fermentation broth to tomato seedlings yielded a significant increase in seedling fresh weight (27.4%), seedling length (12.5%), and root length (57.7%) compared to the control. When the same dosage was applied in the field, we observed increases in tomato plant height (14.7%), stem diameter (12.7%), crown width (16.3%), and maximum fruit diameter (11.5%). These results suggest that NKG-1 has potential commercial application as a biofertilizer or biocontrol agent.

Energy efficiency of acetone, butanol, and ethanol (ABE) recovery by heat-integrated distillation.

PubMed

Grisales Diaz, Victor Hugo; Olivar Tost, Gerard

2018-03-01

Acetone, butanol, and ethanol (ABE) is an alternative biofuel. However, the energy requirement of ABE recovery by distillation is considered elevated (> 15.2 MJ fuel/Kg-ABE), due to the low concentration of ABE from fermentation broths (between 15 and 30 g/l). In this work, to reduce the energy requirements of ABE recovery, four processes of heat-integrated distillation were proposed. The energy requirements and economic evaluations were performed using the fermentation broths of several biocatalysts. Energy requirements of the processes with four distillation columns and three distillation columns were similar (between 7.7 and 11.7 MJ fuel/kg-ABE). Double-effect system (DED) with four columns was the most economical process (0.12-0.16 $/kg-ABE). ABE recovery from dilute solutions by DED achieved energy requirements between 6.1 and 8.7 MJ fuel/kg-ABE. Vapor compression distillation (VCD) reached the lowest energy consumptions (between 4.7 and 7.3 MJ fuel/kg-ABE). Energy requirements for ABE recovery DED and VCD were lower than that for integrated reactors. The energy requirements of ABE production were between 1.3- and 2.0-fold higher than that for alternative biofuels (ethanol or isobutanol). However, the energy efficiency of ABE production was equivalent than that for ethanol and isobutanol (between 0.71 and 0.76) because of hydrogen production in ABE fermentation.

Bacillus methylotrophicus Strain NKG-1, Isolated from Changbai Mountain, China, Has Potential Applications as a Biofertilizer or Biocontrol Agent

PubMed Central

Ge, Beibei; Liu, Binghua; Nwet, Thinn Thinn; Zhao, Wenjun; Shi, Liming; Zhang, Kecheng

2016-01-01

Chemical pesticides are widely used in agriculture, which endangers both environmental health and food safety. Biocontrol is an environmentally-friendly and cost-effective green technique in environmental protection and agricultural production; it generally uses selected bioresources, including beneficial microorganisms. We isolated a novel bacterial strain (NKG-1) from the rare dormant volcanic soils of Changbai Mountain in China’s Jilin Province. The strain was identified as Bacillus methylotrophicus using morphological, biochemical, physiological, and phylogenetic 16S rDNA sequencing data. This strain was able to suppress mycelial growth and conidial germination of numerous plant pathogenic fungi on solid media. A greenhouse experiment showed that application of NKG-1 fermentation broth prior to inoculation of Botrytis cinerea, the cause of gray tomato mold, inhibited growth of the mold by 60%. Furthermore, application of a 100× dilution of NKG-1 fermentation broth to tomato seedlings yielded a significant increase in seedling fresh weight (27.4%), seedling length (12.5%), and root length (57.7%) compared to the control. When the same dosage was applied in the field, we observed increases in tomato plant height (14.7%), stem diameter (12.7%), crown width (16.3%), and maximum fruit diameter (11.5%). These results suggest that NKG-1 has potential commercial application as a biofertilizer or biocontrol agent. PMID:27832162

Recovery method development of sodium chloride-susceptible methicillin-resistant Staphylococcus aureus isolates from ground pork samples.

PubMed

Pang, Lu; Luo, Yanping; Gu, Yihai; Xu, Xiao; Xu, Jin; Zhang, Fenglan; Cui, Shenghui

2015-02-01

The growth of certain methicillin-resistant Staphylococcus aureus (MRSA) isolates could be inhibited by NaCl higher than 2.5%. The objective of this study was to develop an enrichment method to recover NaCl-susceptible MRSA isolates from meat samples. The growth of 12 MRSA and 10 non-MRSA strains was measured in Mueller-Hinton (MH) broth supplemented with 2.5%, 4%, 6.5%, and 7.5% NaCl. Selective agents, including aztreonam, polymyxin B, NaCl, nalidixic acid, and NaN3, were determined for their inhibitory effect to MRSA and non-MRSA strains in MH broth. Based on these data, a two-step enrichment method was developed to recover both NaCl-susceptible and -resistant MRSA isolates in meat products. Comparing to the enrichment method that only used MH broth supplemented with 6.5% NaCl, five additional NaCl-susceptible MRSA isolates were recovered from 92 retail ground pork samples by this newly developed two-step enrichment method. To the best of our knowledge, this is the first study that considers NaCl-susceptible MRSA recovery from ground pork samples. The application of this new enrichment method might expand the diversity of MRSA isolates recovered from various samples.

Development of large area nanostructured silicon-hydrogen alloy material with improved stability for solar cell application by argon dilution method

NASA Astrophysics Data System (ADS)

Dey, Arka; Das, Mrinmay; Datta, Joydeep; Jana, Rajkumar; Dhar, Joydeep; Sil, Sayantan; Biswas, Debasish; Banerjee, Chandan; Ray, Partha Pratim

2016-07-01

Here we have presented the results of large area (30 × 30 cm2) silicon-hydrogen alloy material and solar cell by argon dilution method. As an alternative to hydrogen dilution, argon dilution method has been applied to develop single junction solar cell with appreciable stability. Optimization of deposition conditions revealed that 95% argon dilution gives a nanostructured material with improved transport property and less light induced degradation. The minority carrier diffusion length (L d ) and mobility-lifetime (μτ) product of the material with 95% argon dilution degrades least after light soaking. Also the density of states (DOS) below conduction level reveals that this material is less defective. Solar cell with this argon diluted material has been fabricated with all the layers deposited by argon dilution method. Finally we have compared the argon diluted solar cell results with the optimized hydrogen diluted solar cell. Light soaking study proves that it is possible to develop stable solar cell on large area by argon dilution method and that the degradation of argon diluted solar cell is less than that of hydrogen diluted one. [Figure not available: see fulltext.

Accuracy of different bioinformatics methods in detecting antibiotic resistance and virulence factors from Staphylococcus aureus whole genome sequences.

PubMed

Mason, Amy; Foster, Dona; Bradley, Phelim; Golubchik, Tanya; Doumith, Michel; Gordon, N Claire; Pichon, Bruno; Iqbal, Zamin; Staves, Peter; Crook, Derrick; Walker, A Sarah; Kearns, Angela; Peto, Tim

2018-06-20

Background : In principle, whole genome sequencing (WGS) can predict phenotypic resistance directly from genotype, replacing laboratory-based tests. However, the contribution of different bioinformatics methods to genotype-phenotype discrepancies has not been systematically explored to date. Methods : We compared three WGS-based bioinformatics methods (Genefinder (read-based), Mykrobe (de Bruijn graph-based) and Typewriter (BLAST-based)) for predicting presence/absence of 83 different resistance determinants and virulence genes, and overall antimicrobial susceptibility, in 1379 Staphylococcus aureus isolates previously characterised by standard laboratory methods (disc diffusion, broth and/or agar dilution and PCR). Results : 99.5% (113830/114457) of individual resistance-determinant/virulence gene predictions were identical between all three methods, with only 627 (0.5%) discordant predictions, demonstrating high overall agreement (Fliess-Kappa=0.98, p<0.0001). Discrepancies when identified were in only one of the three methods for all genes except the cassette recombinase, ccrC(b ). Genotypic antimicrobial susceptibility prediction matched laboratory phenotype in 98.3% (14224/14464) cases (2720 (18.8%) resistant, 11504 (79.5%) susceptible). There was greater disagreement between the laboratory phenotypes and the combined genotypic predictions (97 (0.7%) phenotypically-susceptible but all bioinformatic methods reported resistance; 89 (0.6%) phenotypically-resistant, but all bioinformatics methods reported susceptible) than within the three bioinformatics methods (54 (0.4%) cases, 16 phenotypically-resistant, 38 phenotypically-susceptible). However, in 36/54 (67%), the consensus genotype matched the laboratory phenotype. Conclusions : In this study, the choice between these three specific bioinformatic methods to identify resistance-determinants or other genes in S. aureus did not prove critical, with all demonstrating high concordance with each other and phenotypic/molecular methods. However, each has some limitations and therefore consensus methods provide some assurance. Copyright © 2018 American Society for Microbiology.

Rapid Automated Antimicrobial Susceptibility Testing of Streptococcus pneumoniae by Use of the bioMerieux VITEK 2

PubMed Central

Jorgensen, James H.; Barry, Arthur L.; Traczewski, M. M.; Sahm, Daniel F.; McElmeel, M. Leticia; Crawford, Sharon A.

2000-01-01

The VITEK 2 is a new automated instrument for rapid organism identification and susceptibility testing. It has the capability of performing rapid susceptibility testing of Streptococcus pneumoniae with specially configured cards that contain enriched growth medium and antimicrobial agents relevant for this organism. The present study compared the results of testing of a group of 53 challenge strains of pneumococci with known resistance properties and a collection of clinical isolates examined in two study phases with a total of 402 and 416 isolates, respectively, with a prototype of the VITEK 2. Testing was conducted in three geographically separate laboratories; the challenge collection was tested by all three laboratories, and the unique clinical isolates were tested separately by the individual laboratories. The VITEK 2 results of tests with 10 antimicrobial agents were compared to the results generated by the National Committee for Clinical Laboratory Standards reference broth microdilution MIC test method. Excellent interlaboratory agreement was observed with the challenge strains. The overall agreement within a single twofold dilution of MICs defined by the VITEK 2 and reference method with the clinical isolates was 96.3%, although there were a number of off-scale MICs that could not be compared. The best agreement with the clinical isolates was achieved with ofloxacin and chloramphenicol (100%), and the lowest level of agreement among those drugs with sufficient on-scale MICs occurred with trimethoprim-sulfamethoxazole (89.7%). Overall there were 1.3% very major, 6.6% minor, and no major interpretive category errors encountered with the clinical isolates, although >80% of the minor interpretive errors involved only a single log2 dilution difference. The mean time for generation of susceptibility results with the clinical isolates was 8.1 h. The VITEK 2 provided rapid, reliable susceptibility category determinations with both the challenge and clinical isolates examined in this study. PMID:10921932

Enumeration of the contaminating bacterial microbiota in unfermented pasteurized milks enriched with probiotic bacteria.

PubMed

Champagne, C P; Raymond, Y; Gonthier, J; Audet, P

2009-04-01

Pasteurized and unfermented milks supplemented with probiotic bacteria are appearing on the market. It then becomes a challenge to ascertain the undesirable contamination microbiota in the presence of a largely superior population of probiotic bacteria. A method to enumerate the contaminating microbial microbiota in such probiotic-enriched milks was developed. The probiotic cultures, Lactobacillus rhamnosus Lb-Immuni-T and Bifidobacterium animalis subsp. lactis BB-12(R), were added to a pasteurized unfermented milk to reach a minimum of 1 billion CFU per 250 mL portion, as ascertained by plating on de Man - Rogosa - Sharpe (MRS) agar in anaerobic conditions. No growth of B. animalis subsp. lactis BB-12 was noted on plate count agar (PCA) or Petrifilm plates, and the presence of this culture did not affect standard plate counts (SPC) of contaminating bacteria. However, L. rhamnosus formed colonies on PCA and Petrifilm plates. Attempts were thus made to inhibit the growth of the probiotic lactobacilli in PCA. The addition of 2% sodium phosphate (SP) or 5% glycerophosphate (GP) inhibited the growth of the lactobacilli in broths, but pin-point colonies of L. rhamnosus Lb-Immuni-T nevertheless appeared on PCA supplemented with phosphates. SPC could be obtained on PCA + 2% SP by only counting the large colonies, but this resulted in a significant (4.4 fold) underestimation of SPC values. On Petrifilm AC, at dilutions 0 to 2, all colonies were considered as being contaminants, while at dilutions 3 and 4, only large colonies were counted for SPC determinations. There was a direct correlation (R2 = 0.99) between SPC values with Petrifilm in uninoculated milks and those obtained on probiotic-enriched milks. The high correlation obtained over the 102 to 106 CFU/mL range of SPC values show that this Petrifilm method is appropriate to evaluate the microbiological quality of pasteurized milks enriched with L. rhamnosus Lb-Immuni-T and B. animalis subsp. lactis BB-12.

Evaluation of a new selective enrichment broth for detection of group B streptococci in pregnant women.

PubMed

Heelan, Judith S; Struminsky, Judith; Lauro, Patricia; Sung, C James

2005-02-01

Studies at two Brown Medical School-affiliated hospitals were undertaken to evaluate a new selective broth medium (GBS broth) and to compare it to the LIM broth currently used to culture for group B streptococci. Beta-hemolytic group B streptococci produce a carotenoid pigment that turns GBS broth an orange color. From a total of 580 pregnant women, duplicate vaginal-rectal swabs were collected at 35 to 37 weeks of gestation and cultured for group B streptococci, using either LIM broth (a selective broth containing antibiotics) or GBS broth for enrichment. Specimens were either transported to the laboratory or immediately placed in the respective enrichment broths and delivered to the laboratory. GBS broth medium had sensitivity, specificity, and positive and negative predictive values of 87.8, 100, 100, and 95.1% when planted in the laboratory and 90.3, 100, 100 and 97.6%, respectively, when inoculated at bedside. Use of GBS broth would satisfy Centers for Disease Control and Prevention requirements and would provide faster, more-sensitive, and cost-effective detection of group B streptococci in pregnant women.

[Study on the antibacterial activity of four kinds of nano-hydroxyapatite composites against Enterococcus faecalis].

PubMed

Liu, Yi; Zhou, Rongjing; Wu, Hongkun

2015-06-01

This study aims to compare and determine a kind of nano-hydroxyapatite composite material with good antibacterial efficacy on Enterococcusfaecalis (E. faecalis) in vitro. We investigated the antimicrobial activity of four kinds of nano-hydroxyapatite composites, namely, silver/hydroxyapatite composite nanoparticles (Ag/nHA), yttrium/hydroxyapatite composite nanoparticles (Yi/nHA), cerium/hydroxyapatite composite nanoparticles (Ce/nHA), and hydroxyapatite nanoparticles (nHA), against E. faecalis in vitro using the agar diffusion and broth dilution method by measuring the growth inhibition zone and the minimum inhibitory concentration (MIC), respectively. The agar diffusion test results showed that Ag/nHA displayed an obvious growth inhibition zone, whereas Yi/nHA, Ce/nHA, and nHA showed no influence on E. faecalis. The MIC value of Ag/nHA was 1.0 g.L-1, and the three other materials had no effect on E.faecalis even at the high concentration of 32.0 g.L-1. Ag/nHA display a potential antimicrobial efficacy to planktonic E.faecalis. Whereas, the three other kinds of nano-hydroxyapatite composites (Yi/nHA, Ce/nHA, nHA) show no influence.

Antibacterial activity of Thai herbal extracts on acne involved microorganism.

PubMed

Niyomkam, P; Kaewbumrung, S; Kaewnpparat, S; Panichayupakaranant, P

2010-04-01

Ethyl acetate and methanol extracts of 18 Thai medicinal plants were investigated for their antibacterial activity against Propionibacterium acnes, Stapylococcus aureus, and S. epidermidis. Thirteen plant extracts were capable of inhibiting the growth of P. acnes and S. epidermidis, while 14 plant extracts exhibited an inhibitory effect on S. aureus. Based on the broth dilution method, the ethyl acetate extract of Alpinia galanga (L.) Wild. (Zingiberaceae) rhizome showed the strongest antibacterial effect against P. acnes, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 156.0 and 312.0 microg/mL, respectively. On the basis of bioassay-guided purification, the ethyl acetate extract was isolated to afford the antibacterial active compound, which was identified as 1'-acetoxychavicol acetate (1'-ACA). 1'-ACA had a strong inhibitory effect on P. acnes with MIC and MBC values of 62.0 and 250.0 microg/mL, respectively. Thus, 1'-ACA was used as an indicative marker for standardization of A. galanga extract using high performance liquid chromatography. These results suggest that A. galanga extract could be an interesting agent for further studies on an alternative treatment of acne.

Investigation of Total Phenolic and Flavonoid Contents, and Evaluation of Antimicrobial and Antioxidant Activities from Baeckea frutescens Extracts

NASA Astrophysics Data System (ADS)

Nisa, K.; Nurhayati, S.; Apriyana, W.; Indrianingsih, A. W.

2017-12-01

Baeckea frutescens L. is a medicinal plant endemic to the tropical area and it has been used by locals for topical and oral ailments. This study investigated total phenolic and flavonoid contents and also evaluated in vitro antimicrobial and antioxidant activities of of Baeckea frutescens crude extracts. These extracts were assessed for their antibacterial activities against strains of Escherichia coli, Staphylococcus aureus, Salmonella thypii, and Pseudomonas aureginosa by the broth micro-dilution methods using a modified tetrazolium-based colorimetric assay (3-(4, 5-dimethylthiazol)-2, 5-diphenyl tetrazolium bromide (MTT) assay). Baeckea frutescens crude extracts were also tested against the stable DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free-radical. The results indicated that Baeckea frutescens water and ethanol extracts possesed remarkable antibacterial activity with the minimum inhibitory concentration less than 100 μg/ml against Escherichia coli and Salmonella thypi. On the evaluation of the antioxidant activity via DPPH assay, Baeckea frutescens ethanol extracts exhibited a good antioxidant activity with IC50 less than 50 μg/ml and Baeckea frutescens water extracts showed a moderate antioxidant activity with IC50 less than 100 μg/ml.

Chemical composition, antibacterial and antioxidant activities of the essential oils from Thymus satureioides and Thymus pallidus.

PubMed

Ichrak, Ghalbane; Rim, Belaqziz; Loubna, Ait Said; Khalid, Oufdou; Abderrahmane, Romane; Said, El Messoussi

2011-10-01

This study was designed to examine the in vitro antibacterial and antioxidant activities of the essential oils (EOs) of Thymus satureioides (T.s) and T. pallidus (T.p). EOs were isolated by steam distillation and analyzed by capillary gas chromatography and gas chromatography coupled to mass spectrometry (GC-MS). The major constituents of the volatile fraction of T. satureioides were bomeol (29.5%), carvacrol (9.1%), and beta-caryophyllene (8.2%), while those of T. pallidus were camphor (29.8%), dihydrocarvone (17.6%), bomeol (7.6%) and camphene (7.5%). The essential oils were tested against a panel of Gram+ and Gram- bacteria by using agar diffusion and broth dilution methods. The data indicated that the Gram-positive Bacillus subtilis was the most sensitive strain producing an average inhibition zone of 51.7 mm. Furthermore, Pseudomonas aeruginosa, known as a resistant strain, was also sensitive. The samples were also subjected to screening for their possible antioxidant activity by using the 2,2-diphenyl-l-picrylhydrazyl (DPPH) assay. The IC50 values of the oil of T. satureioides and T. pallidus were 0.32 and 11.6 mg/mL, respectively.

Rate of penicillin killing of Staphylococcus aureus and Autobac 1 susceptibility test results.

PubMed Central

Harris, J A; Furtado, D

1982-01-01

A clinical isolate of Staphylococcus aureus interpreted as resistant to penicillin by the Autobac 1 susceptibility testing method (i.e., light-scattering index of 0.77) was found to be susceptible to penicillin by both the disk diffusion and broth dilution techniques. The growth rate of the clinical isolate during a 4-h incubation interval was similar to that of a known sensitive reference strain (S. aureus ATCC 25923) used as a control organism for the Autobac test. The bactericidal effect of penicillin was evaluated by measuring the rate of killing over a 4-h interval. The percentages of organisms surviving exposure to 5.0 or 2.5 U of penicillin G per ml (number of organisms recovered at 3 h/number of organisms introduced as inoculum) were 68 and 76%, respectively, for the clinical isolate and 15 and 21%, respectively, for the reference strain. After 24 h of incubation, penicillin was bactericidal for both strains. The need to increase the time of incubation for those S. aureus isolates resistant to penicillin after 3 h of standard incubation time in the Autobac system is discussed. PMID:7068821

Susceptibility Profiles of Amphotericin B and Posaconazole against Clinically Relevant Mucorales Species under Hypoxic Conditions

PubMed Central

Maurer, Elisabeth; Sparber, Manuela; Lackner, Michaela; Caramalho, Rita; Lass-Flörl, Cornelia

2014-01-01

The effect of hypoxic conditions on the in vitro efficacy of amphotericin B and posaconazole against Mucorales was evaluated by defining MICs with Etest and broth microdilution and identifying minimal fungicidal concentrations (MFCs). With Etest, oxygen-dependent changes were detected, while the MIC and the MFC determined with broth microdilution remained unaltered with reduced oxygen levels. The observed differences depended on the method used. PMID:25451049

Application of polymerase chain reaction for detection of Vibrio parahaemolyticus associated with tropical seafoods and coastal environment.

PubMed

Dileep, V; Kumar, H S; Kumar, Y; Nishibuchi, M; Karunasagar, Indrani; Karunasagar, Iddya

2003-01-01

To study the incidence of Vibrio parahaemolyticus in seafoods, water and sediment by molecular techniques vs conventional microbiological methods. Of 86 samples analysed, 28 recorded positive for V. parahaemolyticus by conventional microbiological method, while 53 were positive by the toxR-targeted PCR, performed directly on enrichment broth lysates. While one sample of molluscan shellfish was positive for tdh gene, trh gene was detected in three enrichment broths of molluscan shellfish. Direct application of PCR to enrichment broths will be useful for the rapid and sensitive detection of potentially pathogenic strains of V. parahemolyticus in seafoods. Vibrio parahaemolyticus is an important human pathogen responsible for food-borne gastroenteritis world-wide. As, both pathogenic and non-pathogenic strains of V. parahaemolyticus exist in the seafood, application of PCR specific for the virulence genes (tdh & trh) will help in detection of pathogenic strains of V. parahaemolyticus and consequently reduce the risk of food-borne illness.

[Determination of sugars, organic acids and alcohols in microbial consortium fermentation broth from cellulose using high performance liquid chromatography].

PubMed

Jiang, Yan; Fan, Guifang; Du, Ran; Li, Peipei; Jiang, Li

2015-08-01

A high performance liquid chromatographic method was established for the determination of metabolites (sugars, organic acids and alcohols) in microbial consortium fermentation broth from cellulose. Sulfate was first added in the samples to precipitate calcium ions in microbial consortium culture medium and lower the pH of the solution to avoid the dissociation of organic acids, then the filtrates were effectively separated using high performance liquid chromatography. Cellobiose, glucose, ethanol, butanol, glycerol, acetic acid and butyric acid were quantitatively analyzed. The detection limits were in the range of 0.10-2.00 mg/L. The linear correlation coefficients were greater than 0.999 6 in the range of 0.020 to 1.000 g/L. The recoveries were in the range of 85.41%-115.60% with the relative standard deviations of 0.22% -4.62% (n = 6). This method is accurate for the quantitative analysis of the alcohols, organic acids and saccharides in microbial consortium fermentation broth from cellulose.

Estimation of Staphylococcus aureus growth parameters from turbidity data: characterization of strain variation and comparison of methods.

PubMed

Lindqvist, R

2006-07-01

Turbidity methods offer possibilities for generating data required for addressing microorganism variability in risk modeling given that the results of these methods correspond to those of viable count methods. The objectives of this study were to identify the best approach for determining growth parameters based on turbidity data and use of a Bioscreen instrument and to characterize variability in growth parameters of 34 Staphylococcus aureus strains of different biotypes isolated from broiler carcasses. Growth parameters were estimated by fitting primary growth models to turbidity growth curves or to detection times of serially diluted cultures either directly or by using an analysis of variance (ANOVA) approach. The maximum specific growth rates in chicken broth at 17 degrees C estimated by time to detection methods were in good agreement with viable count estimates, whereas growth models (exponential and Richards) underestimated growth rates. Time to detection methods were selected for strain characterization. The variation of growth parameters among strains was best described by either the logistic or lognormal distribution, but definitive conclusions require a larger data set. The distribution of the physiological state parameter ranged from 0.01 to 0.92 and was not significantly different from a normal distribution. Strain variability was important, and the coefficient of variation of growth parameters was up to six times larger among strains than within strains. It is suggested to apply a time to detection (ANOVA) approach using turbidity measurements for convenient and accurate estimation of growth parameters. The results emphasize the need to consider implications of strain variability for predictive modeling and risk assessment.

The use of desiccation to treat Staphylococcus aureus biofilm-infected wounds.

PubMed

Park, Eugene; Long, Sarah A; Seth, Akhil K; Geringer, Matthew; Xu, Wei; Chavez-Munoz, Claudia; Leung, Kai; Hong, Seok Jong; Galiano, Robert D; Mustoe, Thomas A

2016-03-01

Chronic wounds colonized with biofilm present a major burden to our healthcare system. While the current paradigm for wound healing is to maintain a moist environment, we sought to evaluate the effects of desiccation, and the ability of honey to desiccate wounds, on wound healing characteristics in Staphylococcus aureus biofilm wounds. In vivo biofilm wound healing after exposure to open-air desiccation, honey, molasses, and saline was analyzed using a rabbit ear model of S. aureus biofilm wounds previously developed by our group. Wound morphology was examined using scanning electron microscopy and granulation tissue deposition was measured using light microscopy with hematoxylin and eosin staining. Viable bacterial counts in rabbit ear biofilm wounds and scabs were measured using a drop dilution method. In vitro S. aureus growth curves were established using tryptic soy broth containing honey and glycerol. Gene expression analysis of rabbit ear wounds was performed using reverse transcription quantitative PCR. Rabbit ear S. aureus biofilm wounds exposed to open-air desiccation, honey, and molasses developed a dry scab, which displaced the majority of biofilm bacteria off of the wound bed. Wounds treated with open-air desiccation, honey, and molasses expressed lower levels of the inflammatory markers tumor necrosis factor-α and interleukin-1β at postoperative day 12 compared with wounds treated with saline, and had increased levels of granulation tissue formation. In vitro growth of S. aureus in tryptic soy broth was inhibited by the presence of honey to a greater extent than by the presence of osmolality-matched glycerol. Desiccation of chronic wounds colonized with biofilm via exposure to open air or honey leads to improved wound healing by decreasing bacterial burden and inflammation, and increasing granulation tissue formation. The ability of honey to help heal chronic wounds is at least in part due to its ability to desiccate bacterial biofilm, but other factors clearly contribute. © 2015 by the Wound Healing Society.

Comparison of different sampling techniques and of different culture methods for detection of group B streptococcus carriage in pregnant women.

PubMed

El Aila, Nabil A; Tency, Inge; Claeys, Geert; Saerens, Bart; Cools, Piet; Verstraelen, Hans; Temmerman, Marleen; Verhelst, Rita; Vaneechoutte, Mario

2010-09-29

Streptococcus agalactiae (group B streptococcus; GBS) is a significant cause of perinatal and neonatal infections worldwide. To detect GBS colonization in pregnant women, the CDC recommends isolation of the bacterium from vaginal and anorectal swab samples by growth in a selective enrichment medium, such as Lim broth (Todd-Hewitt broth supplemented with selective antibiotics), followed by subculture on sheep blood agar. However, this procedure may require 48 h to complete. We compared different sampling and culture techniques for the detection of GBS. A total of 300 swabs was taken from 100 pregnant women at 35-37 weeks of gestation. For each subject, one rectovaginal, one vaginal and one rectal ESwab were collected. Plating onto Columbia CNA agar (CNA), group B streptococcus differential agar (GBSDA) (Granada Medium) and chromID Strepto B agar (CA), with and without Lim broth enrichment, were compared. The isolates were confirmed as S. agalactiae using the CAMP test on blood agar and by molecular identification with tDNA-PCR or by 16S rRNA gene sequence determination. The overall GBS colonization rate was 22%. GBS positivity for rectovaginal sampling (100%) was significantly higher than detection on the basis of vaginal sampling (50%), but not significantly higher than for rectal sampling (82%). Direct plating of the rectovaginal swab on CNA, GBSDA and CA resulted in detection of 59, 91 and 95% of the carriers, respectively, whereas subculturing of Lim broth yielded 77, 95 and 100% positivity, respectively. Lim broth enrichment enabled the detection of only one additional GBS positive subject. There was no significant difference between GBSDA and CA, whereas both were more sensitive than CNA. Direct culture onto GBSDA or CA (91 and 95%) detected more carriers than Lim broth enrichment and subculture onto CNA (77%). One false negative isolate was observed on GBSDA, and three false positives on CA. In conclusion, rectovaginal sampling increased the number GBS positive women detected, compared to vaginal and/or rectal sampling. Direct plating on CA and/or GBSDA provided rapid detection of GBS that was at least as sensitive and specific as the CDC recommended method of Lim broth subcultured onto non chromogenic agar.

New denture adhesive containing miconazole nitrate polymeric microparticles: Antifungal, adhesive force and toxicity properties.

PubMed

Cartagena, Andrés Felipe; Esmerino, Luís Antonio; Polak-Junior, Rogerio; Olivieri Parreiras, Sibelli; Domingos Michél, Milton; Farago, Paulo Vitor; Campanha, Nara Hellen

2017-02-01

The purpose of this study was to develop a new oral drug delivery system by incorporating polymeric miconazole nitrate (MN) microparticles on an experimental antifungal denture adhesive (DA). Spray drying Eudragit L-100 (E) and Gantrez MS-955 (G) MN-microparticles were incorporated in DA. DAE1, DAG1, DAEG1, DAE2, DAG2, DAEG2 groups were obtained from the combination of polymers used in MN-microparticles (E, G and EG) and concentration of MN into DA (1, for 1% and 2, for 2%). DA with 2% pure MN (DAM) and DA without microparticles or drug (DACT) were both control groups. All groups were evaluated to determine microbiological assay, adhesive force and toxicity. Minimum inhibitory concentration (MIC) against Candida albicans was performed by broth micro-dilution and agar dilution methods in extract of DAs and conventional gel form (Daktarin ® ). Adhesive load testing was made between acrylic resin samples on a universal testing machine after immersion in water. The toxicity of several dilutions of DAs was performed with Artemia salina bioassay after 24 and 48h. Data of adhesive force were evaluated with two-way ANOVA and Bonferroni tests (α=0.05). The concentration required to kill 50% (LC50) was determined using the Provit analysis. DA with polymeric microparticles and pure drug presented MIC between 1.25-5μg/mL similar to MIC values of DAM. DAEG2, DAEG1, DAG20 showed the most actives against C. albicans. The best adhesive properties were exhibited by DAEG2, consisting of high initial adhesive force which was maintained for up to 6h. The extracts of all DA presented low or not toxicity at 24 and 48h. DA containing 2% of MN loaded in microparticles made by Gantrez MS-955 alone or combined with Eudragit L-100 produce effective antifungal activity, good adhesive force, and no toxicity effect being a promising therapeutics for removable denture wearers affected by denture stomatitis. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Rapid surface colony counts determination with three new miniaturised techniques.

PubMed

Malik, K A

1977-01-01

Three different miniaturised methods for the rapid surface viable counting are described. The methods were tried in parallel to seven different existing methods (Table 1) for viable counts and were found to be easier, quicker and insome cases more accurate. The techniques require about 10% of the material and time needed for conventional spread-plates method and the results were in no way inferior to that (Table 1 and 2). Mini agar discs were cut aseptically with an especially designed stainless steel agar disc cutter (25 mm internal and 28 mm external diameter, Fig. 1b) or with a test tube of similar diameter. The area of the resulted mini-agar-disc of 25 mm diameter was kept such (about 1/10th of the normal plate) that the ratio of the colony-bearing area to the inoculm remained the same as on big plates in spread-plate-method (Table 2). In normal Petri dishes (about 90 mm diameter) up to seven mini agar discs were possible to cut. Each small agar disc was seperated from the other mini-disc by a distance of at least 6 mm (Fig. 1a). The empty place around the disc was still enlarged during over drying of the plates and during incubation. This created complete isolation from the neighbouring disc. For micro-determination of surface viable counts 10 micronl from each dilution was delivered on a well-dired mini-disc with a piston micropipette. The inoculm was immediately spread on the whole mini-disc with a specially designed flame sterilizable platinum-Mini-spreader (Fig. 2a). No spinning of the plate was needed. Alternatively the dropping pipette and spreader was replaced by a calibrated platinum wire Loop-spreader (Fig. 2b). A loop of 3 mm internal diameter made from a platinum-iridium wire of 0.75 mm thickness proved most useful and carried a drop of 10 micronl. Differences especially in surface tension of various diluting fluids did not influence to drop of this size and no recalibration was needed for water and nutrient broth. The loop was further shaped to Loop-spreader form. From each bacterial suspension 10 micronl were carried and spread on each mini-disc. The method is useful for pathogenic organisms as the loop can readily be flame sterilized. For routine purposes where only approximate numbers of bacteria need to be known a still rapid semiquantitative method was deviced making use of a calibrated stainless steel Stamping-disc (Fig. 2c). A disc of 25mm diameter and 1 mm thickness delivered approximateyl 10 microlitres of supensions and was found to be most useful to stamp seven dilutions on a single plate. In collections and bacteriology laboratories where by conventional methods large number of plates are to be plated and counted the presented techniques could prove most convenient, rapid and economical.

New phenyl-ethanediols from the culture broth of Boletus edulis.

PubMed

Yang, Wan-Qiu; Qin, Xiang-Dong; Shao, Hong-Jun; Fang, Li-Zhen; Wang, Fei; Ding, Zhi-Hui; Dong, Ze-Jun; Liu, Ji-Kai

2007-04-01

A new phenyl-ethanediol, (1S)-(4-acetylphenyl)-1, 2-ethanediol (1), and a new natural product, (1S)-(3-ethenylphenyl)-1, 2-ethanediol (2), were isolated from the culture broth of the basidiomycete Boletus edulis together with three related known compounds, 1-(4-ethylphenyl)-1, 2-ethanediol (3), 1-(3-ethylphenyl)-1, 2-ethanediol (4) and 1-(3-formylphenyl)-ethanone (5). Their structures were elucidated by spectroscopic methods including extensive 2D-NMR techniques.

Carbon Capture and Storage (CCS): Risk assessment focused on marine bacteria.

PubMed

Borrero-Santiago, A R; DelValls, T A; Riba, I

2016-09-01

Carbon capture and storage (CCS) is one of the options to mitigate the negative effects of the climate change. However, this strategy may have associated some risks such as CO2 leakages due to an escape from the reservoir. In this context, marine bacteria have been underestimated. In order to figure out the gaps and the lack of knowledge, this work summarizes different studies related to the potential effects on the marine bacteria associated with an acidification caused by a CO2 leak from CSS. An improved integrated model for risk assessment is suggested as a tool based on the rapid responses of bacterial community. Moreover, this contribution proposes a strategy for laboratory protocols using Pseudomona stanieri (CECT7202) as a case of study and analyzes the response of the strain under different CO2 conditions. Results showed significant differences (p≤0.05) under six diluted enriched medium and differences about the days in the exponential growth phase. Dilution 1:10 (Marine Broth 2216 with seawater) was selected as an appropriate growth medium for CO2 toxicity test in batch cultures. This work provide an essential and a complete tool to understand and develop a management strategy to improve future works related to possible effects produced by potential CO2 leaks. Copyright © 2016 Elsevier Inc. All rights reserved.

[Continuous ethanol fermentation coupled with recycling of yeast flocs].

PubMed

Wang, Bo; Ge, Xu-Meng; Li, Ning; Bai, Feng-Wu

2006-09-01

A continuous ethanol fermentation system composed of three-stage tanks in series coupled with two sedimentation tanks was established. A self-flocculating yeast strain developed by protoplast fusion from Saccharomyces cerevisiae and Schizosaccharomyces pombe was applied. Two-stage enzymatic hydrolysate of corn powder containing 220g/L of reducing sugar, supplemented with 1.5g/L (NH4)2HPO4 and 2.5g/L KH2PO4, was used as the ethanol fermentation substrate and fed into the first fermentor at the dilution rate of 0.057h(-1). The yeast flocs separated by sedimentation were recycled into the first fermentor as two different models: activation-recycle and direct recycle. The quasi-steady states were obtained for both operation models after the fermentation systems experienced short periods of transitions. Activation process helped enhance the performance of ethanol fermentation at the high dilution rates. The broth containing more than 101g/L ethanol, 3.2g/L residual reducing sugar and 7.7g/L residual total sugar was produced. The ethanol productivity was calculated to be 5.77g/(L x h), which increased by more than 70% compared with that achieved in the same tank in series system without recycling of yeast cells.

[Detection of Brucella with an automatic hemoculture system: Bact/Alert].

PubMed

Casas, J; Partal, Y; Llosá, J; Leiva, J; Navarro, J M; de la Rosa, M

1994-12-01

The ability of in vitro and in vivo detection of Brucella spp. with the Bact/Alert system was studied. Three strains of Brucella melitensis and two of Brucella abortus were used. Different dilutions of the five strains were performed in trypticase soy broth (TSB), achieving concentrations of 1 cfu/ml, 5 cfu/ml, 10 cfu/ml and 100 cfu/ml. Ten ml of each dilution and strain were inoculated into 5 aerobic bottles Bact/Alert and 5 biphasic Hemóline bottles. Furthermore, over a 9 month period, 8,216 bottles of Bact/Alert bottles from hospitalized patients and from the emergency department were processed in the authors' laboratory. The mean detection time for Brucella growth was from 2 to 3 days with the Bact/Alert system, and 14 days in the biphasic bottles. Former bottles processed in the authors' laboratory, 11 aerobic bottles belonged to 5 patients in whom brucelosis was confirmed by bloodculture. The Bact/Alert system detected Brucella melitensis in only on bottle at 2.9 days of incubation. In 7 bottles Bact/Alert detected B. melitensis by a blind pass of these bottles at 10 to 20 days of incubation. These results suggest that the Bact/Alert system does not totally solve the diagnosis of brucellosis. Blind passes of the bloodcultures are required.

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

Vipulanandan, C.; Ghurye, G.L.; Willson, R.C.

The use of surfactants is of increasing interest for remediation of petroleum hydrocarbons in groundwater and soil. Surfactants increase the accessibility of adsorbed hydrocarbons and mobilize immiscible petroleum hydrocarbons for treatment. Biosurfactants have the advantage of biodegradability and non-toxicity over their synthetic counterparts, and can be produced from renewable sources. In this study the production of biosurfactant from molasses was investigated in continuously stirred batch reactors. The effects of substrate concentration, yeast extract and peptone on biomass accumulation and biosurfactant production were investigated. Biosurfactant production was quantified by surface tension reduction and critical micelle dilution (CMD). Biosurfactant production was directlymore » correlated with biomass production, and was improved with the addition of yeast extract. Centrifugation of the whole broth reduced surface tension. The performance of the biosurfactant produced from molasses under non-aseptic condition is comparable to other published results.« less

Anti-fungal activity of Morinda citrifolia (noni) extracts against Candida albicans: an in vitro study.

PubMed

Barani, K; Manipal, Sunayana; Prabu, D; Ahmed, Adil; Adusumilli, Preethi; Jeevika, C

2014-01-01

The aim of this study was to investigate the anti-fungal activity of Morinda citrifolia fruit extract on Candida albicans. Juice extract from M. citrifolia fruit was lyophilized and used in anti-fungal testing. Anti-fungal activity of M. citrifolia fruit extract against C. albicans was tested in vitro at various concentrations. The inhibitory effect of M. citrifolia extract on C. albicans was determined by agar culture and applied broth dilution test. M. citrifolia extract at 1000 μg/ml concentration effectively inhibited the growth of C. albicans (16.6 ± 0.3) compared with the positive control - amphotericin B (20.6 ± 0.6). It was found to be a dose-dependent reaction. M. citrifolia fruit extract had an anti-fungal effect on C. albicans and the inhibitory effect varied with concentration.

Rapid Identification of Bacteria in Positive Blood Culture Broths by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry▿

PubMed Central

Stevenson, Lindsay G.; Drake, Steven K.; Murray, Patrick R.

2010-01-01

Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry is a rapid, accurate method for identifying bacteria and fungi recovered on agar culture media. We report herein a method for the direct identification of bacteria in positive blood culture broths by MALDI-TOF mass spectrometry. A total of 212 positive cultures were examined, representing 32 genera and 60 species or groups. The identification of bacterial isolates by MALDI-TOF mass spectrometry was compared with biochemical testing, and discrepancies were resolved by gene sequencing. No identification (spectral score of <1.7) was obtained for 42 (19.8%) of the isolates, due most commonly to insufficient numbers of bacteria in the blood culture broth. Of the bacteria with a spectral score of ≥1.7, 162 (95.3%) of 170 isolates were correctly identified. All 8 isolates of Streptococcus mitis were misidentified as being Streptococcus pneumoniae isolates. This method provides a rapid, accurate, definitive identification of bacteria within 1 h of detection in positive blood cultures with the caveat that the identification of S. pneumoniae would have to be confirmed by an alternative test. PMID:19955282

Rapid identification of bacteria in positive blood culture broths by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

PubMed

Stevenson, Lindsay G; Drake, Steven K; Murray, Patrick R

2010-02-01

Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry is a rapid, accurate method for identifying bacteria and fungi recovered on agar culture media. We report herein a method for the direct identification of bacteria in positive blood culture broths by MALDI-TOF mass spectrometry. A total of 212 positive cultures were examined, representing 32 genera and 60 species or groups. The identification of bacterial isolates by MALDI-TOF mass spectrometry was compared with biochemical testing, and discrepancies were resolved by gene sequencing. No identification (spectral score of < 1.7) was obtained for 42 (19.8%) of the isolates, due most commonly to insufficient numbers of bacteria in the blood culture broth. Of the bacteria with a spectral score of > or = 1.7, 162 (95.3%) of 170 isolates were correctly identified. All 8 isolates of Streptococcus mitis were misidentified as being Streptococcus pneumoniae isolates. This method provides a rapid, accurate, definitive identification of bacteria within 1 h of detection in positive blood cultures with the caveat that the identification of S. pneumoniae would have to be confirmed by an alternative test.

A study of an aroma extraction method and evaluation of the aroma extract contribution to the palatability and reinforcement effect of dried bonito using mice.

PubMed

Amitsuka, Takahiko; Okamura, Maya; Shiibashi, Hiroko; Yamamoto, Naoto; Saito, Tsukasa; Nammoku, Takashi; Tsuzuki, Satoshi; Inoue, Kazuo; Fushiki, Tohru

2014-01-01

Japanese cuisine has provided satisfying meals by fully utilizing the characteristic aroma and taste of katsuodashi (dried bonito broth), though it is not rich in sugars or fats. Katsuodashi is a very basic and indispensable element in Japanese cuisine, and is a hot water extract of katsuobushi (dried bonito). It has been reported that a dextrin solution containing natural dried bonito broth has a significant reinforcement effect, and has been suggested that the olfactory stimulation is important for the reinforcement effect. We examined various source materials for broth and identified an optimal method of aroma extraction by two-bottle choice and conditioned place preference tests in mice. By two-bottle choice tests, a solution containing arabushi (a type of katsuobushi) aroma extract obtained by a supercritical CO2 extraction method showed a significantly high preference. The conditioned place preference test showed the dashi-taste solution with arabushi supercritical CO2 extract had a reinforcement effect. Our results suggest that the arabushi extract obtained by supercritical CO2 extraction contains components responsible for preference and reinforcement effects in mice; it could become conducive to making Japanese cuisine more satisfying and palatable.

[Experimental study of bacteriostatic activity of Chinese herbal medicines on primary cariogenic bacteria in vitro].

PubMed

Wang, S; Fan, M; Bian, Z

2001-09-01

To screen some Chinese herbal medicines for their inhibitory activity on cariogenic bacteria, and investigate their active ingredients, and measure their minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC). Active components were isolated from every tested Chinese herbal medicine by means of aqueous extraction and ethanolic extraction. Berberine was purified from Coptis chinensis Fra. Disk agar diffusion method was employed in screening herbs with inhibiting effect on cariogenic bacteria. MIC and MBC were determined by broth dilution method. Against Streptococcus mutans Ingbritt, MBCs of Magnolia officinalis ethanolic extract, Berberine, Coptis chinensis Fra aqueous extract and Coptis chinensis Fra ethanolic extract were 0.488, 0.625, 7.800 and 1.950 g/L respectively. Against Streptococcus sobrinus 6715, MBCs of Magnolia extract, Coptis chinensis Fra ethanolic extract, Rhus chinensis Mill ethanolic extract and Phellodendron chinen ethanolic extract were 0.488, 0.625, 1.950, 3.900, 3.900 and 3.900 g/L respectively. Against Actinomyces viscosus ATCC 19246, MBCs of Berberine, Coptis chinensis Fra aqueous extract, Coptis chinensis Fra ethanolic extract, Rheum palmatum L aqueous extract and Rheum palmatum L ethanolic extract were 1.250, 3.900, 3.900, 15.600 and 31.250 g/L respectively. Magnolia officinalis, Coptis chinensis Fran, Rheum palmatum L aqueous extracts exhibit strong inhibition on cariogenic bacteria. Magnolia officinalis ethanolic extract has the strongest bactericidal effects on Streptococcus mutans and Streptococcus sobrinus.

Chemical composition and antimicrobial activity of Cymbopogon nardus citronella essential oil against systemic bacteria of aquatic animals.

PubMed

Wei, Lee Seong; Wee, Wendy

2013-06-01

This paper describes chemical composition and antimicrobial activity of Cymbopogon nardus citronella essential oil against Edwardsiella spp. (n = 21), Vibrio spp. (n = 6), Aeromonas spp. (n = 2), Escherichia coli (n = 2), Salmonella spp. (n = 2), Flavobacterium spp. (n = 1), Pseudomonas spp. (n = 1) and Streptococcus spp. (n = 1) isolated from internal organs of aquatic animals. Due to the ban of antibiotics for aquaculture use, this study was carried out to evaluate the potential of citronella essential oil as alternative to commercial antibiotic use against systemic bacteria in cultured aquatic animals. The essential oil of C. nardus was prepared by using the steam distillation method and the chemical composition of the essential oil was analyzed by gas chromatography-mass spectroscopy (GC-MS). Minimum inhibitory concentration (MIC) of the essential oil tested against bacterial isolates from various aquatic animals and ATCC type strains were determined using two-fold broth micro dilution method with kanamycin and eugenol as positive controls. A total of 22 chemical compounds were detected in C. nardus essential oil with 6-octenal, 3, 7-dimethyl- or citronellal representing the major compounds (29.6%). The MIC values of the citronella oil ranged from 0.244 µg/ml to 0.977 µg/ml when tested against the bacterial isolates. The results of the present study revealed the potential of C. nardus essential oil as alternative to commercial antibiotics for aquaculture use.

Evaluation of anti-bacterial and anti-oxidant potential of andrographolide and echiodinin isolated from callus culture of Andrographis paniculata Nees

PubMed Central

Arifullah, Mohmmed; Namsa, Nima Dandu; Mandal, Manabendra; Chiruvella, Kishore Kumar; Vikrama, Paritala; Gopal, Ghanta Rama

2013-01-01

Objective To evaluate the anti-bacterial and anti-oxidant activity of andrographolide (AND) and echiodinin (ECH) of Andrographis paniculata. Methods In this study, an attempt has been made to demonstrate the anti-microbial and anti-oxidant activity of isolated AND and ECH by broth micro-dilution method and 2,2-diphenyl-2-picryl-hydrazyl (DPPH) assay, respectively. Structure elucidation was determined by electro-spray ionization-MSD, NMR (1H and 13C) and IR spectra. Results AND was effective against most of the strains tested including Mycobacterium smegmatis, showing broad spectrum of growth inhibition activity with Minimum inhibitory concentration values against Staphylococcus aureus (100 µg/mL), Streptococcus thermophilus (350 µg/mL) Bacillus subtilis (100 µg/mL), Escherichia coli (50 µg/mL), Mycobacterium smegmatis (200 µg/mL), Klebsiella pneumonia (100 µg/mL), and Pseudomonas aeruginosa (200 µg/mL). ECH showed specific anti-bacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa at a concentration higher than 225 µg/mL. Both AND and ECH were not effective against the two yeast strains, Candida albicans and Saccharomyces cerevisiae tested in this study. Conclusion This preliminary study showed promising anti-bacterial activity and moderate free radical scavenging activity of AND and ECH, and it may provide the scientific rationale for its popular folklore medicines. PMID:23905016

Comparative Study of Hydroalcoholic Extracts of Momordica charantia L. against Foodborne Pathogens

PubMed Central

Rakholiya, Kalpna; Vaghela, P.; Rathod, T.; Chanda, Sumitra

2014-01-01

The antimicrobial effect of 24 different hydroalcoholic extracts (100, 75, 50 and 25% methanol and water) obtained from four parts (leaf+stem (aerial), peel, pulp and seed) of Momordica charantia L. were investigated against five Gram-positive, six Gram-negative and four fungal strains. The extraction was done by individual cold percolation method using hexane, different hydroalcoholic solvent (100, 75, 50 and 25% methanol) and water. The antimicrobial activity was done by agar well diffusion assay. The extracts, which showed >15 mm zone of inhibition, were further screened to determine minimum inhibitory concentration and minimum bactericidal concentration using a broth dilution method performed in 96-well microtitre plate. The extractive yield was highest in aqueous extracts of all the four parts closely followed by 25% methanol. Micrococcus flavus was the most susceptible Gram-positive bacteria and Pseudomonas testosteroni was the most susceptible Gram-negative bacteria. The highest antibacterial activity was shown by 100% methanol. The Gram-negative Pseudomonas spp. was more susceptible towards all the extracts than the Gram-positive bacteria or fungal strains investigated. One hundred percent and 50% methanol extracts of seed showed lowest minimum inhibitory concentration and minimum bactericidal concentration values, that is <39 and 625 μg/ml, respectively, against Pseudomonas pictorum. Therefore, these extracts would be of interest in the control of Pseudomonas spp. in food industry as well as used for therapeutic purposes. PMID:24843188

In-vitro antimicrobial activity screening of some ethnoveterinary medicinal plants traditionally used against mastitis, wound and gastrointestinal tract complication in Tigray Region, Ethiopia

PubMed Central

Kalayou, Shewit; Haileselassie, Mekonnen; Gebre-egziabher, Gebremedhin; Tiku'e, Tsegay; Sahle, Samson; Taddele, Habtamu; Ghezu, Mussie

2012-01-01

Objective To screen the antibacterial activity of nine ethnoveterinary plants traditionally used for the treatment of mastitis, wound and gastrointestinal complications. Methods Hydroalcoholic exctracts of medicinal plants namely, Achyranthes aspera (A. aspera) L. (Family Asparagaceae), Ficus caria (F. caria) (Family Moraceae), Malvi parviflora (M. parviflora) (Family Malvaceae), Vernonia species (V. species) (local name Alakit, Family Asteraceae), Solanum hastifolium (S. hastifolium) (Family Solanaceae), Calpurinia aurea (C. aurea) (Ait) Benth (Family Fabaceae), Nicotiana tabacum (N. tabacum) L. (Family Solanaceae), Ziziphus spina-christi (Z. spina-christi) (Family Rhamnaceae), Croton macrostachys (C. macrostachys) (Family Euphorbiaceae), were screened against clinical bacterial isolates of veterinary importance from October 2007 to April 2009. The antibacterial activity was tested using disc diffusion at two concentrations (200 mg/mL and 100 mg/mL) and broth dilution methods using 70% methanol macerated leaf extracts. Results With the exception of S. hastifolium all plant extracts exhibited antibacterial activity. Among the medicinal plants tested C. aurea, C. macrostachyus, A. aspera, N. tabacum and vernonia species (Alakit) showed the most promising antimicrobial properties. Conclusions It can be concluded that many of the tested plants have antibacterial activity and supports the traditional usage of the plants for mastitis, wound and gastrointestinal complications treatment. Further studies into their toxicity and phytochemistry is advocated. PMID:23569962

Effect of essential oils prepared from Thai culinary herbs on sessile Candida albicans cultures.

PubMed

Hovijitra, Ray S; Choonharuangdej, Suwan; Srithavaj, Theerathavaj

2016-01-01

Although medicinal herbs with fungicidal effects have been ubiquitously employed in traditional medicine, such effects of culinary herbs and spices still have to be elucidated. Therefore, it is noteworthy to determine the antifungal efficacy of some edible herbs used in Thai cuisine against sessile Candida albicans cultures, and to inquire if they can be further utilized as naturally-derived antifungals. Fourteen essential oils extracted from Thai culinary herbs and spices were tested for their antifungal activity against C. albicans using the agar disk diffusion method followed by broth micro-dilution method for the determination of minimum inhibitory concentration (MIC) and minimum fungicidal concentration. The oils with potent antifungal effects against planktonic fungi were then assessed for their effect against sessile fungus (adherent organisms and established biofilm culture). MIC of the oils against sessile C. albicans was evaluated by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide reduction assay. All selected culinary herbs and spices, except galangal, garlic, and turmeric, exhibited inhibitory effects on planktonic yeast cells. Cinnamon bark and sweet basil leaf essential oils exhibited potent fungicidal effect on planktonic and sessile fungus. Sessile MICs were 8-16 times higher than planktonic MICs. Consequently, both cinnamon bark and sweet basil leaf herbal oils seem to be highly effective anti-Candida choices. (J Oral Sci 58, 365-371, 2016).

Diagnostic microbiology in veterinary dermatology: present and future.

PubMed

Guardabassi, Luca; Damborg, Peter; Stamm, Ivonne; Kopp, Peter A; Broens, Els M; Toutain, Pierre-Louis

2017-02-01

The microbiology laboratory can be perceived as a service provider rather than an integral part of the healthcare team. The aim of this review is to discuss the current challenges of providing a state-of-the-art diagnostic veterinary microbiology service including the identification (ID) and antimicrobial susceptibility testing (AST) of key pathogens in veterinary dermatology. The Study Group for Veterinary Microbiology (ESGVM) of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) identified scientific, technological, educational and regulatory issues impacting the predictive value of AST and the quality of the service offered by microbiology laboratories. The advent of mass spectrometry has significantly reduced the time required for ID of key pathogens such as Staphylococcus pseudintermedius. However, the turnaround time for validated AST methods has remained unchanged for many years. Beyond scientific and technological constraints, AST methods are not harmonized and clinical breakpoints for some antimicrobial drugs are either missing or inadequate. Small laboratories, including in-clinic laboratories, are usually not adequately equipped to run up-to-date clinical microbiologic diagnostic tests. ESGVM recommends the use of laboratories employing mass spectrometry for ID and broth micro-dilution for AST, and offering assistance by expert microbiologists on pre- and post-analytical issues. Setting general standards for veterinary clinical microbiology, promoting antimicrobial stewardship, and the development of new, validated and rapid diagnostic methods, especially for AST, are among the missions of ESGVM. © 2017 The Authors. Veterinary Dermatology published by John Wiley & Sons Ltd on behalf of the ESVD and ACVD.

Anticariogenic activity and phytochemical studies of crude extract from some Indian plant leaves

PubMed Central

Barad, Mahesh K.; Ishnava, Kalpesh B.; Chauhan, Jenabhai B.

2014-01-01

Aim: The aim was to screen the selected Indian plants for their antibacterial efficacy against four cariogenic bacteria Lactobacillus acidophilus (LA)(Microbial Type Culture Collection [MTCC]-*447), Lactobacillus casei (LC) (MTCC-1423), Streptococcus mutans (SMU) (MTCC-890) and Staphylococcus aureus (MTCC-96). To identify and characterize active principle present in these plants for the treatment of dental caries. Materials and Methods: The dried plant leaves materials are extracted by cold extraction using hexane, ethyl acetate, methanol, and distilled water. The solvents were evaporated, and the dried masses were suspended in dimethyl sulfoxide and used for anticariogenic activity by agar well diffusion method. Minimum inhibitory concentration (MIC) was evaluated by two-fold serial broth dilution method. Preliminary phytochemical analysis of effective extract was carried out by thin-layer chromatography (TLC) and bioautography. Results: Ethyl acetate and hexane extract of Eucalyptus globules was found most effective against L. acidophilus with MIC value 31 μg/ml and 62 μg/ml, respectively. Ethyl acetate extracts of Acacia nilotica and methanolic extract of E. globules also exhibited antibacterial activity against SMU and L. casei with MIC value of 50 μg/ml. Qualitative analysis of E. globules revealed the presence of alkaloids, terpenoids, phenolic compounds, and cardiac glycosides. The active principle responsible for the anticariogenic activity from E. globules were separated by TLC and subjected to bioautography using SMU, LA and LC. Conclusion: Anticariogenic activity and preliminary phytochemical analysis revealed that E. globule have potential to treat dental caries. PMID:26401353

Chemical composition and antimicrobial activity of Cymbopogon nardus citronella essential oil against systemic bacteria of aquatic animals

PubMed Central

Wei, Lee Seong; Wee, Wendy

2013-01-01

Background & Objectives This paper describes chemical composition and antimicrobial activity of Cymbopogon nardus citronella essential oil against Edwardsiella spp. (n = 21), Vibrio spp. (n = 6), Aeromonas spp. (n = 2), Escherichia coli (n = 2), Salmonella spp. (n = 2), Flavobacterium spp. (n = 1), Pseudomonas spp. (n = 1) and Streptococcus spp. (n = 1) isolated from internal organs of aquatic animals. Due to the ban of antibiotics for aquaculture use, this study was carried out to evaluate the potential of citronella essential oil as alternative to commercial antibiotic use against systemic bacteria in cultured aquatic animals. Materials & Methods The essential oil of C. nardus was prepared by using the steam distillation method and the chemical composition of the essential oil was analyzed by gas chromatography–mass spectroscopy (GC–MS). Minimum inhibitory concentration (MIC) of the essential oil tested against bacterial isolates from various aquatic animals and ATCC type strains were determined using two-fold broth micro dilution method with kanamycin and eugenol as positive controls. Results A total of 22 chemical compounds were detected in C. nardus essential oil with 6-octenal, 3, 7-dimethyl- or citronellal representing the major compounds (29.6%). The MIC values of the citronella oil ranged from 0.244 µg/ml to 0.977 µg/ml when tested against the bacterial isolates. Conclusion The results of the present study revealed the potential of C. nardus essential oil as alternative to commercial antibiotics for aquaculture use. PMID:23825733

Preliminary antifungal activity assay of selected chlorine-containing derivatives of xanthone and phenoxyethyl amines.

PubMed

Klesiewicz, Karolina; Żelaszczyk, Dorota; Trojanowska, Danuta; Bogusz, Bożena; Małek, Marianna; Waszkielewicz, Anna; Szkaradek, Natalia; Karczewska, Elżbieta; Marona, Henryk; Budak, Alicja

2018-06-20

The aim of this study was to preliminary evaluate antifungal activity diverse group of chlorine-containing xanthone and phenoxyethyl amine derivatives - and to select most promising compounds for further studies. The antifungal efficacy of 16 compounds was tested with qualitative and quantitative methods against both reference and clinical strains of dermatophytes, moulds and yeasts. The disc-diffusion method has demonstrated that from 16 tested compounds, 7 possess good antifungal activity against dermatophytes and/or moulds while none of them has shown good efficacy against yeasts or bacterial strains. The most active compounds (2, 4, 10, 11, 12, 15, 16) were tested quantitatively by broth dilution method to obtain MIC values. The MIC values against dermatophytes ranged from 8 to 64 μg/mL. Compound 2 was the most active one against dermatophytes (MIC 50 and MIC 90 were 8 μg/mL). The MIC values for moulds ranged from 16 to 256 μg/mL. Compound 4 was the most active one against moulds, with MIC 50 and MIC 90 values amounting to 32 μg/mL. Among the tested compounds, compound 4 (derivative of xanthone) was the most active one and expressed good antifungal efficacy against clinical strains of dermatophytes and moulds. However, another xanthone derivative (compound 2) was the most active and selective against dermatophytes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

In-situ visualisation of hyphal structure and arrangement in mycoprotein pastes.

PubMed

Miri, Taghi; Cox, Philip W; Fryer, Peter J

2003-02-01

A novel method to examine the morphology and structure of fungal hyphae in solid pastes used for the production of meat alternative product is presented. A sample of fermentation broth was fluorescently stained with Calcofluor White and added back to the broth, mixed and then a paste made using ultra-filtration. Fibre visualisation was by fluorescence microscopy and quantification by manual image analysis. This method enables the determination of fibre length and orientation within the paste. Imaging of the hypha fibre paste proved that its structure was 'isotropic', i.e. that fibres were randomly oriented in all directions. Processing of the paste altered the orientation of the fibres, the method was able to identify and quantify the changes in fibre position.

Susceptibility profiles of amphotericin B and posaconazole against clinically relevant mucorales species under hypoxic conditions.

PubMed

Maurer, Elisabeth; Binder, Ulrike; Sparber, Manuela; Lackner, Michaela; Caramalho, Rita; Lass-Flörl, Cornelia

2015-02-01

The effect of hypoxic conditions on the in vitro efficacy of amphotericin B and posaconazole against Mucorales was evaluated by defining MICs with Etest and broth microdilution and identifying minimal fungicidal concentrations (MFCs). With Etest, oxygen-dependent changes were detected, while the MIC and the MFC determined with broth microdilution remained unaltered with reduced oxygen levels. The observed differences depended on the method used. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

New antioxidants from the culture broth of Hericium coralloides.

PubMed

Kim, Ji-Yul; Woo, E-Eum; Lee, In-Kyoung; Yun, Bong-Sik

2018-05-17

In our effort to find antioxidants from the higher fungi, we isolated three new compounds (1-3) with a known compound, spirobenzofuran (4), from the culture broth of Hericium coralloides. Bioassay-guided fractionation led to the isolation of these compounds, and we determined the chemical structures through spectroscopic methods. These compounds exhibited antioxidant activity in the range of IC 50 values of 29-66 μM in the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging assay.

Reduced susceptibility of clinical strains of Mycobacterium tuberculosis to reactive nitrogen species promotes survival in activated macrophages

PubMed Central

Idh, Jonna; Andersson, Blanka; Lerm, Maria; Raffetseder, Johanna; Eklund, Daniel; Woksepp, Hanna; Werngren, Jim; Mansjö, Mikael; Sundqvist, Tommy; Stendahl, Olle

2017-01-01

Background Drugs such as isoniazid (INH) and pretomanid (PRT), used against Mycobacterium tuberculosis are active partly through generation of reactive nitrogen species (RNS). The aim of this study was to explore variability in intracellular susceptibility to nitric oxide (NO) in clinical strains of M. tuberculosis. Method Luciferase-expressing clinical M. tuberculosis strains with or without INH resistance were exposed to RNS donors (DETA/NO and SIN-1) in broth cultures and bacterial survival was analysed by luminometry. NO-dependent intracellular killing in a selection of strains was assessed in interferon gamma/lipopolysaccharide-activated murine macrophages using the NO inhibitor L-NMMA. Results When M. tuberculosis H37Rv was compared to six clinical isolates and CDC1551, three isolates with inhA mediated INH resistance showed significantly reduced NO-susceptibility in broth culture. All strains showed a variable but dose-dependent susceptibility to RNS donors. Two clinical isolates with increased susceptibility to NO exposure in broth compared to H37Rv were significantly inhibited by activated macrophages whereas there was no effect on growth inhibition when activated macrophages were infected by clinical strains with higher survival to NO exposure in broth. Furthermore, the most NO-tolerant clinical isolate showed increased resistance to PRT both in broth culture and the macrophage model compared to H37Rv in the absence of mutational resistance in genes associated to reduced susceptibility against PRT or NO. Conclusion In a limited number of clinical M. tuberculosis isolates we found a significant difference in susceptibility to NO between clinical isolates, both in broth cultures and in macrophages. Our results indicate that mycobacterial susceptibility to cellular host defence mechanisms such as NO need to be taken into consideration when designing new therapeutic strategies. PMID:28704501

An adapted isolation procedure reveals Photobacterium spp. as common spoilers on modified atmosphere packaged meats.

PubMed

Hilgarth, M; Fuertes-Pèrez, S; Ehrmann, M; Vogel, R F

2018-04-01

The genus Photobacterium comprises species of marine bacteria, commonly found in open-ocean and deep-sea environments. Some species (e.g. Photobacterium phosphoreum) are associated with fish spoilage. Recently, culture-independent studies have drawn attention to the presence of photobacteria on meat. This study employed a comparative isolation approach of Photobacterium spp. and aimed to develop an adapted isolation procedure for recovery from food samples, as demonstrated for different meats: Marine broth is used for resuspending and dilution of food samples, followed by aerobic cultivation on marine broth agar supplemented with meat extract and vancomycin at 15°C for 72 h. Identification of spoilage-associated microbiota was carried out via Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry using a database supplemented with additional mass spectrometry profiles of Photobacterium spp. This study provides evidence for the common abundance of multiple Photobacterium species in relevant quantities on various modified atmosphere packaged meats. Photobacterium carnosum was predominant on beef and chicken, while Photobacterium iliopiscarium represented the major species on pork and Photobacterium phosphoreum on salmon, respectively. This study demonstrates highly frequent isolation of multiple photobacteria (Photobacterium carnosum, Photobacterium phosphoreum, and Photobacterium iliopiscarium) from different modified-atmosphere packaged spoiled and unspoiled meats using an adapted isolation procedure. The abundance of photobacteria in high numbers provides evidence for the hitherto neglected importance and relevance of Photobacterium spp. to meat spoilage. © 2018 The Society for Applied Microbiology.

Effect of sampling and short isolation methodologies on the recovery of human pathogenic Yersinia enterocolitica from pig tonsils.

PubMed

Van Damme, Inge; Berkvens, Dirk; De Zutter, Lieven

2012-07-01

The objective of this study was to determine the effect of sampling (swab samples compared to destructive samples) on isolation rates of human pathogenic Yersinia enterocolitica from pig tonsils. Moreover, the relative efficiency of different rapid, routinely applicable isolation methods was evaluated. Therefore, swab and destructive samples from tonsils of 120 pigs at slaughter were analyzed in parallel using direct plating and different enrichment methods. Salmonella-Shigella-desoxycholate-calcium chloride (SSDC) agar, cefsulodin-irgasan-novobiocin (CIN) agar, and Yersinia enterocolitica chromogenic medium (YeCM) were used as selective agar media. For enrichment, irgasan-ticarcillin-potassium chlorate (ITC) broth and peptone-sorbitol-bile (PSB) broth were incubated at 25°C for 48 h. Overall, 55 tonsils (45.8%) were positive for Y. enterocolitica bioserotype 4/O:3. Recovery was significantly higher using the destructive method compared to the swabbing method. Direct plating resulted in 47 and 28 Y. enterocolitica-positive destructive and swab samples, respectively. Alkali treatment of PSB and ITC enrichment broths significantly increased recovery of pathogenic Y. enterocolitica from destructive tonsil samples. The performance of YeCM for qualitative and quantitative isolation of pathogenic Y. enterocolitica from pig tonsils was equal to SSDC and CIN. In conclusion, direct plating and ISO 10273: 2003 with minor modifications are suitable and rapid methods for isolation of pathogenic Y. enterocolitica from destructive tonsil samples.

Collaborative ring-trial of Dynabeads anti-Salmonella for immunomagnetic separation of stressed Salmonella cells from herbs and spices.

PubMed

Mansfield, L; Forsythe, S

1996-02-01

Eight laboratories participated in a Salmonella detection ring-trial which compared selective enrichment by conventional broths with immunomagnetic separation (IMS) using Dynabeads Anti-Salmonella. Laboratories analyzed six types of herbs and spices that were spiked with one of six freeze-dried Salmonella species. Each herb and spice analysis comprised of 12 samples (25 g each) which had been spiked at three different levels, plus a negative control and stored for one week prior to testing. Out of a total 468 samples analyzed, 195 (41.7%) were positive by both methods. Eighteen samples were positive only by IMS enrichment, in comparison with 19 positive samples by conventional enrichment broths and not IMS. These results confirm the potential use of IMS as an alternative to enrichment broths for Salmonella isolation.

DuPont Qualicon BAX System polymerase chain reaction assay. Performance Tested Method 100201.

PubMed

Tice, George; Andaloro, Bridget; Fallon, Dawn; Wallace, F Morgan

2009-01-01

A recent outbreak of Salmonella in peanut butter has highlighted the need for validation of rapid detection methods. A multilaboratory study for detecting Salmonella in peanut butter was conducted as part of the AOAC Research Institute Emergency Response Validation program for methods that detect outbreak threats to food safety. Three sites tested spiked samples from the same master mix according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA-BAM) method and the BAX System method. Salmonella Typhimurium (ATCC 14028) was grown in brain heart infusion for 24 h at 37 degrees C, then diluted to appropriate levels for sample inoculation. Master samples of peanut butter were spiked at high and low target levels, mixed, and allowed to equilibrate at room temperature for 2 weeks. Spike levels were low [1.08 most probable number (MPN)/25 g]; high (11.5 MPN/25 g) and unspiked to serve as negative controls. Each master sample was divided into 25 g portions and coded to blind the samples. Twenty portions of each spiked master sample and five portions of the unspiked sample were tested at each site. At each testing site, samples were blended in 25 g portions with 225 mL prewarmed lactose broth until thoroughly homogenized, then allowed to remain at room temperature for 55-65 min. Samples were adjusted to a pH of 6.8 +/- 0.2, if necessary, and incubated for 22-26 h at 35 degrees C. Across the three reporting laboratories, the BAX System detected Salmonella in 10/60 low-spike samples and 58/60 high-spike samples. The reference FDA-BAM method yielded positive results for 11/60 low-spike and 58/60 high-spike samples. Neither method demonstrated positive results for any of the 15 unspiked samples.

A Microfluidic Channel Method for Rapid Drug-Susceptibility Testing of Pseudomonas aeruginosa

PubMed Central

Matsumoto, Yoshimi; Grushnikov, Andrey; Kikuchi, Kazuma; Noji, Hiroyuki; Yamaguchi, Akihito; Yagi, Yasushi

2016-01-01

The recent global increase in the prevalence of antibiotic-resistant bacteria and lack of development of new therapeutic agents emphasize the importance of selecting appropriate antimicrobials for the treatment of infections. However, to date, the development of completely accelerated drug susceptibility testing methods has not been achieved despite the availability of a rapid identification method. We proposed an innovative rapid method for drug susceptibility testing for Pseudomonas aeruginosa that provides results within 3 h. The drug susceptibility testing microfluidic (DSTM) device was prepared using soft lithography. It consisted of five sets of four microfluidic channels sharing one inlet slot, and the four channels are gathered in a small area, permitting simultaneous microscopic observation. Antimicrobials were pre-introduced into each channel and dried before use. Bacterial suspensions in cation-adjusted Mueller–Hinton broth were introduced from the inlet slot and incubated for 3 h. Susceptibilities were microscopically evaluated on the basis of differences in cell numbers and shapes between drug-treated and control cells, using dedicated software. The results of 101 clinically isolated strains of P. aeruginosa obtained using the DSTM method strongly correlated with results obtained using the ordinary microbroth dilution method. Ciprofloxacin, meropenem, ceftazidime, and piperacillin caused elongation in susceptible cells, while meropenem also induced spheroplast and bulge formation. Morphological observation could alternatively be used to determine the susceptibility of P. aeruginosa to these drugs, although amikacin had little effect on cell shape. The rapid determination of bacterial drug susceptibility using the DSTM method could also be applicable to other pathogenic species, and it could easily be introduced into clinical laboratories without the need for expensive instrumentation. PMID:26872134

Influence of enrichment broths on multiplex PCR detection of total coliform bacteria, Escherichia coli and Clostridium perfringens, in spiked water samples.

PubMed

Worakhunpiset, S; Tharnpoophasiam, P

2009-07-01

Although multiplex PCR amplification condition for simultaneous detection of total coliform bacteria, Escherichia coli and Clostridium perfringens in water sample has been developed, results with high sensitivity are obtained when amplifying purified DNA, but the sensitivity is low when applied to spiked water samples. An enrichment broth culture prior PCR analysis increases sensitivity of the test but the specific nature of enrichment broth can affect the PCR results. Three enrichment broths, lactose broth, reinforced clostridial medium and fluid thioglycollate broth, were compared for their influence on sensitivity and on time required with multiplex PCR assay. Fluid thioglycollate broth was the most effective with shortest enrichment time and lowest detection limit.

Comparison of culture based methods for the isolation of Clostridium difficile from stool samples in a research setting.

PubMed

Lister, Michelle; Stevenson, Emma; Heeg, Daniela; Minton, Nigel P; Kuehne, Sarah A

2014-08-01

Effective isolation of Clostridium difficile from stool samples is important in the research setting, especially where low numbers of spores/vegetative cells may be present within a sample. In this study, three protocols for stool culture were investigated to find a sensitive, cost effective and timely method of C. difficile isolation. For the initial enrichment step, the effectiveness of two different rich media, cycloserine-cefoxitin fructose broth (CCFB) and cycloserine-cefoxitin mannitol broth with taurocholate and lysozyme (CCMB-TAL) were compared. For the comparison of four different, selective solid media; Cycloserine-cefoxitin fructose agar (CCFA), Cycloserine-cefoxitin egg yolk agar (CCEY), ChromID C. difficile and tryptone soy agar (TSA) with 5% sheep's blood with and without preceding broth enrichment were used. As a means to enable differentiation between C. difficile and other fecal flora, the effectiveness of the inclusion of a pH indictor (1% Neutral Red), was also evaluated. The data derived indicated that CCFB is more sensitive than CCMB-TAL, however, the latter had an improved recovery rate. A broth enrichment step had a reduced sensitivity over direct plating. ChromID C. difficile showed the best recovery rate whereas CCEY egg yolk agar was the most sensitive of the four. The addition of 1% Neutral Red did not show sufficient colour change when added to CCEY egg yolk agar to be used as a differential medium. For a low cost, timely and sensitive method of isolating C. difficile from stool samples we recommend direct plating onto CCEY egg yolk agar after heat shock. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Identification of Streptococcus agalactiae by fluorescent in situ hybridization compared to culturing and the determination of prevalence of Streptococcus agalactiae colonization among pregnant women in Bushehr, Iran.

PubMed

Tajbakhsh, Saeed; Norouzi Esfahani, Marjan; Emaneini, Mohammad; Motamed, Niloofar; Rahmani, Elham; Gharibi, Somayyeh

2013-09-08

Pregnant women colonized by Streptococcus agalactiae (group B streptococci [GBS]) may transfer this microorganism to their newborns. S. agalactiae is an important cause of pneumonia, sepsis, and meningitis in newborns. Fluorescent in situ hybridization (FISH) is considered as a method of identification in the field of diagnostic microbiology. In this paper, we have designed a study to compare the DNA FISH after 7 h Lim broth enrichment and culturing for the identification of S. agalactiae and to determine the prevalence of vaginal colonization by S. agalactiae among pregnant women in Bushehr, Iran. Vaginal swab specimens were obtained from 285 pregnant women at 35 weeks or more than 35 weeks of gestation. The specimens were inoculated into Lim broth. In order to evaluate the sensitivity and specificity of GBS DNA FISH after 7 h Lim broth enrichment, the specimens were tested using both FISH and conventional culture methods. In addition, the prevalence of GBS colonization was determined. Based on the results of this study, both the sensitivity and specificity of FISH were 100%. S. agalactiae was detected by both culture and FISH in 27 of the 285 pregnant women. Thus, the prevalence of GBS colonization was 9.5%. Since short-term (7 h) Lim broth enrichment followed by FISH using oligonucleotide probes showed a high sensitivity and specificity, this protocol is therefore a highly accurate and relatively rapid method for the detection of S. agalactiae. Our analysis suggests that the use of DNA FISH to screen for S. agalactiae colonization in pregnant women may be considered in the absence of GBS culture availability.

[Serotype distribution and antimicrobial resistance of Salmonella isolates from retail chicken carcasses in six provinces of China].

PubMed

Hu, Y J; He, Y Y; Wang, Y R; Liu, C; Wang, M M; Gan, X; Wang, W; Yan, S F; Bai, Y; Peng, Z X; Li, F Q; Xu, J

2018-04-06

Objective: To obtain the serotype diversity and antimicrobial resistance of Salmonella isolates recovered from retail chicken carcasses for sale in six regions of China. Methods: From August 2010 to March 2012, each month 20 retail chicken carcasses including freshly slaughtered, chilled and frozen samples were collected from supermarkets and farmer's markets in 7 monitoring sites in Beijing, Jilin province, Inner Mongolia Autonomous, Shanxi province, Jiangsu province and Guangdong province, respectively. Samples were routinely collected for 12 months for each site. 1 680 chicken carcasses were collected in total and 2 629 Salmonella strains were isolated by PCR and biochemical method. Luminex xMAP method and classical slide agglutination method were carried out to determine isolates' serotypes. Minimal inhibitory concentrations (MICs) of 10 classes of antimicrobials including 14 agents were determined using broth micro-dilution method. Mocular methods were used to determine antimicrobial resistance genes of CIP-CTX-CT co-resistant isolates. Results: In all, 2 629 Salmonella isolates, there were 17 seorgroups and 58 serotypes, B and D1 were the dominant serogroups with rates of 34.7% ( n= 913) and 31.0% ( n= 815), Enteritidis (30.8%, n= 810), Indiana (17.6%, n= 463), Infantis (10.6%, n= 278) were the top three serovars. We found 224 CIP-CTX co-resistant S . Indiana containing 3 colistin resistant strains, one of them carrying mcr -1 gene and being ESBLs positive, which demonstrated a nine multi drug resistance against 11 antimicrobials tested. Conclusion: These data began to describe the complicated serovar diversity and heavy antimicrobial resistance of Salmonella isolates recovered from retail chicken carcasses in six regions of China. The findings highlight the emergence of ciprofloxacin and cefotaxime co-resistant S . Indiana and also a mcr -1 positive S . Indiana with heavy multi drug resistance.

Use of Granada Medium To Detect Group B Streptococcal Colonization in Pregnant Women

PubMed Central

Rosa-Fraile, Manuel; Rodriguez-Granger, Javier; Cueto-Lopez, Marina; Sampedro, Antonio; Gaye, Enrique Biel; Haro, José Manuel; Andreu, Antonia

1999-01-01

Direct inoculation onto Granada medium (GM) in plates and tubes was compared to inoculation into a selective Todd-Hewitt broth (with 8 μg of gentamicin per ml and 15 μg of nalidixic acid per ml) for detection of group B streptococci (GBS) in pregnant women with 800 vaginal and 450 vaginoanorectal samples. Comparatively, GM was found to be as sensitive as the selective broth for the detection of GBS in vaginal specimens and more sensitive than selective broth for the detection of GBS in vaginoanorectal samples (96 versus 82%). The use of GM improved the time to reporting of a GBS-positive result by at least 24 h and reduced the direct cost of screening. We have also found that the inconvenience of anaerobic incubation of GM plates can be avoided when a cover slide is placed upon the inoculum, because aerobic incubation in GM plates with cover slides causes GBS to develop the same pigmentation that it develops with incubation under anaerobic conditions. These data support the routine use of GM plates or tubes as a more accurate, easier, and cheaper method of identification of GBS-colonized women compared to the enrichment broth technique. PMID:10405420

Ultraviolet Light Enhances the Bovine Serum Albumin Fixation for Acid Fast Bacilli Stain

PubMed Central

Lai, Pei-Yin; Lee, Shih-Yi; Chou, Yu-Ching; Fu, Yung-Chieh; Wu, Chen-Cheng; Chiueh, Tzong-Shi

2014-01-01

The use of a liquid culture system such as MGIT broth has greatly improved the sensitivity of isolating mycobacteria in clinical laboratories. Microscopic visualization of acid fast bacilli (AFB) in the culture positive MGIT broth remains the first routine step for rapidly indicating the presence of mycobacteria. We modified an ultraviolet (UV) light fixation process to increase AFB cells adherence to the slide. The retained haze proportion of a 1-cm circle marked area on the smear slide was quantified after the staining procedure indicating the adherence degree of AFB cells. More AFB cells were preserved on the slide after exposure to UV light of either germicidal lamp or UV crosslinker in a time-dependent manner. We demonstrated both the bovine serum albumin (BSA) in MGIT media and UV light exposure were required for enhancing fixation of AFB cells. While applying to AFB stains for 302 AFB positive MGIT broths in clinics, more AFB cells were retained and observed on smear slides prepared by the modified fixation procedure rather than by the conventional method. The modified fixation procedure was thus recommended for improving the sensitivity of microscopic diagnosis of AFB cells in culture positive MGIT broth. PMID:24586725

Surface characteristics of Bacillus cereus and its adhesion to stainless steel.

PubMed

Peng, J S; Tsai, W C; Chou, C C

2001-04-11

The ability of a Bacillus cereus strain, isolated from spoiled milk, to adhere to the surface of stainless steel chips was evaluated during its growth in diluted tryptic soy broth (DTSB). The number of cells that adhered to the surface increased markedly as the culture reached the end of the log phase and entered stationary phase, and continued to increase with further incubation. The surface properties of cells from the log, stationary, and late stationary phases were measured by hydrophobic interaction chromatography (HIC) and electrostatic interaction chromatography (ESIC). It was found that surface hydrophobicity of B. cereus vegetative cells from the late stationary phase was the highest followed by those from the stationary phase and the log phase cultures. While the vegetative cells prepared from stationary phase and log phase cultures, respectively, had the highest and the lowest surface charges. Adhesion of B. cereus vegetative cells to stainless steel was positively correlated with the cell surface hydrophobicity (R = 0.979). Surface hydrophobicity and surface positive charge noted on the spores harvested from diluted tryptic soy agar (DTSA) and Mn2+-tryptone glucose extract agar were higher than those harvested from the sucrose or lactose-added DTSA. A wide variation in the surface charge values was noted on the surface of various spores prepared from cultures grown on the four different media tested, while their ability to adhere to stainless steel chips in phosphate buffered saline (PBS) showed no significant difference (p > 0.05). Similarly, the number of spores or vegetative cells adhering to stainless steel suspended in PBS, milk or diluted milk (1000 x) did not differ significantly (p > 0.05).

Modeling the behavior of Listeria monocytogenes during enrichment in half Fraser broth; impact of pooling and the duration of enrichment on the detection of L. monocytogenes in food.

PubMed

Augustin, Jean-Christophe; Kalmokoff, Martin; Ells, Timothy; Favret, Sandra; Desreumaux, Jennifer; Decourseulles Brasseur, Emilie; Gnanou Besse, Nathalie

2016-12-01

A stochastic model describing the growth of Listeria monocytogenes during enrichment in half Fraser was developed for the purpose of estimating the effects of modifications to the first enrichment step of the EN ISO 11290-1 detection method. Information pertaining to the variability of growth rates, physiological state of the cell, and the behavior of individual cells contaminating the food were obtained from previously published studies. We used this model to investigate the impact of pooling enrichment broths (wet pooling) on the performance of the standard method. For validation of the model, the numbers of L. monocytogenes occurring in 88 naturally contaminated foods following pre-enrichment were compared to model-simulated microbial counts. The model was then used to perform simulations representative of the natural contamination observed for smoked salmon in the European baseline survey of 2010-2011. The model-estimated L. monocytogenes levels following individual enrichment or following the pooling of five broths where only one would be contaminated were compared. The model indicated a 10% loss of method sensitivity resulting from wet pooling. The model also predicted a 5% decrease in the sensitivity of the method when the duration of the enrichment was reduced from 24 to 22 h. Copyright © 2016 Elsevier Ltd. All rights reserved.

Outcomes of using wet pooling to detect STEC and Salmonella

USDA-ARS?s Scientific Manuscript database

Objective: The objective of this work was to examine the reliability of wet pooling sample broths. Experimental Design & Analysis: Fresh sample enrichment broths (n=737) were used to prepare 148 wet pools of 5 broths each. The initial broths and the pools were screened for STEC and Salmonella. ...

Antibacterial activity of acidified sodium benzoate against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in tryptic soy broth and on cherry tomatoes.

PubMed

Chen, Huaiqiong; Zhong, Qixin

2018-06-02

Concerns about undesirable by-products from chlorine sanitation of fresh produce and the limited efficacy with the presence of organic matter, have led to studies on alternative washing solutions. The aim of this study was to evaluate the antibacterial activities of acidified sodium benzoate (NaB) solutions against Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes in growth medium and on cherry tomatoes. Experimentally, the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs, >3 Log reduction) of NaB against E. coli O157:H7 ATCC 43895, S. Enteritidis, and L. monocytogenes Scott A were determined at pH 7.0-4.0 using micro-broth dilution method and agar plating method, respectively. The reduction of the three bacteria in tryptic soy broth (TSB) by 500 and 1000 ppm NaB at pH 2.0, 2.5 and 3.0 for 30 min at 21 °C was compared. Residual bacterial cocktails inoculated on cherry tomatoes were determined after soaking in 3000 ppm NaB solution adjusted to pH 2.0 for 3 min at 21 °C. Results showed that the MBC of NaB reduced from >10,000 ppm at pH 7.0 to 1000 ppm at pH 4.0 and was identical for the three bacteria. The log reduction of bacteria in TSB indicated that 1000 ppm NaB at pH 2.0 was the most effective in killing the three pathogens. The respective reduction of E. coli O157:H7 and S. enterica cocktails inoculated on cherry tomatoes immersed in 3000 ppm NaB (pH 2.0) at 21 °C for 3 min was 4.99 ± 0.57 and 4.08 ± 0.65 log CFU/g, which was significantly higher (p < 0.05) than the treatments of 200 ppm free chlorine at pH 6.5. Conversely, the reduction of L. monocytogenes on tomatoes by 3000 ppm NaB (4.88 ± 0.73 log CFU/g) was similar (p > 0.05) to 200 ppm chlorine. Furthermore, the reduction of bacterial cocktails on tomatoes by 3000 ppm NaB at pH 2.0 was not affected after adding 1% tomato puree, and bacteria were not detected in NaB washing solutions with and without 1% tomato puree and on following un-inoculated tomatoes. This study showed that acidified NaB solution may be used as an alternative post-harvest wash of produce. Copyright © 2018 Elsevier B.V. All rights reserved.

Total body water and lean body mass estimated by ethanol dilution

NASA Technical Reports Server (NTRS)

Loeppky, J. A.; Myhre, L. G.; Venters, M. D.; Luft, U. C.

1977-01-01

A method for estimating total body water (TBW) using breath analyses of blood ethanol content is described. Regression analysis of ethanol concentration curves permits determination of a theoretical concentration that would have existed if complete equilibration had taken place immediately upon ingestion of the ethanol; the water fraction of normal blood may then be used to calculate TBW. The ethanol dilution method is applied to 35 subjects, and comparison with a tritium dilution method of determining TBW indicates that the correlation between the two procedures is highly significant. Lean body mass and fat fraction were determined by hydrostatic weighing, and these data also prove compatible with results obtained from the ethanol dilution method. In contrast to the radioactive tritium dilution method, the ethanol dilution method can be repeated daily with its applicability ranging from diseased individuals to individuals subjected to thermal stress, strenuous exercise, water immersion, or the weightless conditions of space flights.

Antimicrobial activity of commercial Olea europaea (olive) leaf extract.

PubMed

Sudjana, Aurelia N; D'Orazio, Carla; Ryan, Vanessa; Rasool, Nooshin; Ng, Justin; Islam, Nabilah; Riley, Thomas V; Hammer, Katherine A

2009-05-01

The aim of this research was to investigate the activity of a commercial extract derived from the leaves of Olea europaea (olive) against a wide range of microorganisms (n=122). Using agar dilution and broth microdilution techniques, olive leaf extract was found to be most active against Campylobacter jejuni, Helicobacter pylori and Staphylococcus aureus [including meticillin-resistant S. aureus (MRSA)], with minimum inhibitory concentrations (MICs) as low as 0.31-0.78% (v/v). In contrast, the extract showed little activity against all other test organisms (n=79), with MICs for most ranging from 6.25% to 50% (v/v). In conclusion, olive leaf extract was not broad-spectrum in action, showing appreciable activity only against H. pylori, C. jejuni, S. aureus and MRSA. Given this specific activity, olive leaf extract may have a role in regulating the composition of the gastric flora by selectively reducing levels of H. pylori and C. jejuni.

Tiamulin resistance in porcine Brachyspira pilosicoli isolates.

PubMed

Pringle, M; Landén, A; Franklin, A

2006-02-01

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

Escherichia coli growth under modeled reduced gravity

NASA Technical Reports Server (NTRS)

Baker, Paul W.; Meyer, Michelle L.; Leff, Laura G.

2004-01-01

Bacteria exhibit varying responses to modeled reduced gravity that can be simulated by clino-rotation. When Escherichia coli was subjected to different rotation speeds during clino-rotation, significant differences between modeled reduced gravity and normal gravity controls were observed only at higher speeds (30-50 rpm). There was no apparent affect of removing samples on the results obtained. When E. coli was grown in minimal medium (at 40 rpm), cell size was not affected by modeled reduced gravity and there were few differences in cell numbers. However, in higher nutrient conditions (i.e., dilute nutrient broth), total cell numbers were higher and cells were smaller under reduced gravity compared to normal gravity controls. Overall, the responses to modeled reduced gravity varied with nutrient conditions; larger surface to volume ratios may help compensate for the zone of nutrient depletion around the cells under modeled reduced gravity.

Multichannel electrochemical microbial detection unit

NASA Technical Reports Server (NTRS)

Wilkins, J. R.; Young, R. N.; Boykin, E. H.

1978-01-01

The paper describes the design and capabilities of a compact multichannel electrochemical unit devised to detect and automatically indicate detection time length of bacteria. By connecting this unit to a strip-chart recorder, a permanent record is obtained of the end points and growth curves for each of eight channels. The experimental setup utilizing the multichannel unit consists of a test tube (25 by 150 mm) containing a combination redox electrode plus 18 ml of lauryl tryptose broth and positioned in a 35-C water bath. Leads from the electrodes are connected to the multichannel unit, which in turn is connected to a strip-chart recorder. After addition of 2.0 ml of inoculum to the test tubes, depression of the push-button starter activates the electronics, timer, and indicator light for each channel. The multichannel unit is employed to test tenfold dilutions of various members of the Enterobacteriaceae group, and a typical dose-response curve is presented.

Xyloglucan, hibiscus and propolis for the prevention of urinary tract infections: results of in vitro studies.

PubMed

Fraile, Benito; Alcover, Javier; Royuela, Mar; Rodríguez, David; Chaves, Concepción; Palacios, Ricardo; Piqué, Núria

2017-06-01

To assess the properties of a medical device containing xyloglucan, propolis and hibiscus to create a bioprotective barrier to avoid the contact of uropathogenic Escherichia coli strains on cell walls in models of intestinal (CacoGoblet) and uroepithelial (RWPE-1) cells (derived from normal human prostate epithelium). Two uropathogenic E. coli strains (expressing type 1 fimbriae and P fimbriae) were used to assess, by electronic microscopy and ELISA, the barrier properties of the medical device. The antimicrobial activity was assessed in broth dilution assays. The three components (xyloglucan, propolis and hibiscus) did not alter E. coli cell integrity in intestinal and uroepithelial cell models and were devoid of antibacterial activity. The three components avoided bacterial contact in both cell monolayers. The nonpharmacological barrier properties of xyloglucan, propolis and hibiscus confirm the role of the medical device for the management of urinary tract infections.

Antifungal polypeptides

DOEpatents

Altier, Daniel J [Waukee, IA; Ellanskaya, Irina [Kyiv, UA; Ellanskaya, legal representative, Natalia; Gilliam, Jacob T [Norwalk, IA; Hunter-Cevera, Jennie [Elliott City, MD; Presnail, James K [Avondale, PA; Schepers, Eric [Port Deposit, MD; Simmons, Carl R [Des Moines, IA; Torok, Tamas [Richmond, CA; Yalpani, Nasser [Johnston, IA

2009-09-15

The invention relates to antifungal compositions and methods for protecting a plant from a fungal pathogen. Compositions including antifungal polypeptides isolated from a fungal fermentation broth are provided.

Enhanced inhibition of Aspergillus niger on sedge (Lepironia articulata) treated with heat-cured lime oil.

PubMed

Matan, N; Matan, N; Ketsa, S

2013-08-01

This study aimed to examine heat curing effect (30-100°C) on antifungal activities of lime oil and its components (limonene, p-cymene, β-pinene and α-pinene) at concentrations ranging from 100 to 300 μl ml(-1) against Aspergillus niger in microbiological medium and to optimize heat curing of lime oil for efficient mould control on sedge (Lepironia articulata). Broth dilution method was employed to determine lime oil minimum inhibitory concentration, which was at 90 μl ml(-1) with heat curing at 70°C. Limonene, a main component of lime oil, was an agent responsible for temperature dependencies of lime oil activities observed. Response surface methodology was used to construct the mathematical model describing a time period of zero mould growth on sedge as functions of heat curing temperature and lime oil concentration. Heat curing of 90 μl ml(-1) lime oil at 70°C extended a period of zero mould growth on sedge to 18 weeks under moist conditions. Heat curing at 70°C best enhanced antifungal activity of lime oil against A. niger both in medium and on sedge. Heat curing of lime oil has potential to be used to enhance the antifungal safety of sedge products. © 2013 The Society for Applied Microbiology.

Antityrosinase and antimicrobial activities from Thai medicinal plants.

PubMed

Dej-Adisai, Sukanya; Meechai, Imron; Puripattanavong, Jindaporn; Kummee, Sopa

2014-04-01

Various dermatological disorders and microbial skin infection can cause hyperpigmentation. Therefore, screenings for whitening and antimicrobial agents from Thai medicinal plants have been of research interest. Seventy-seven ethanol plant extracts were investigated for antityrosinase activity, eleven samples showed the tyrosinase inhibition more than 50 % were further preliminary screening for antimicrobial activity by agar disc diffusion and broth micro-dilution methods. Artocarpus integer (Thunb.) Merr. (Moraceae) root extract, which showed the potential of tyrosinase inhibition with 90.57 ± 2.93 % and antimicrobial activity against Staphylococcus aureus, S. epidermidis, Propionibacterium acnes and Trichophyton mentagophytes with inhibition zone as 9.10 ± 0.00, 10.67 ± 0.09, 15.25 ± 0.05 and 6.60 ± 0.17 mm, respectively was selected for phytochemical investigation. Three pure compounds were isolated as artocarpin, cudraflavone C and artocarpanone. And artocarpanone exhibited anti-tyrosinase effect; artocarpin and cudraflavone C also showed the potential of antibacterial activity against S. aureus, S. epidermidis and P. acnes with MIC at 2, 4 and 2 μg/ml, respectively and MBC at 32 μg/ml for these bacteria. So, these pure compounds are interesting for further study in order to provide possibilities of new whitening and antibacterial development. This will be the first report of phytochemical investigation of A. integer root.

Antibacterial and anti-inflammatory effects of Jeju medicinal plants against acne-inducing bacteria.

PubMed

Kim, Sang-Suk; Kim, Ji-Young; Lee, Nam Ho; Hyun, Chang-Gu

2008-04-01

Propionibacterium acnes and Staphylococcus epidermidis are pus-forming bacteria that trigger inflammation in acne. The present study was conducted to evaluate the antimicrobial activities of Jeju medicinal plants against these etiologic agents of acne vulgaris. Ethanol extracts of Jeju plants were tested for antimicrobial activities by disc diffusion and broth dilution methods. The results from the disc diffusion assays revealed that four medicinal plants, Mollugo pentaphylla, Angelica anomala, Matteuccia orientalis, and Orixa japonica inhibited the growth of both pathogens. Among these, A. anomala had strong inhibitory effects. Its MIC values were 15.6 microg/ml and 125 microg/ml against P. acnes and S. epidermidis, respectively. The cytotoxic effects of the four extracts were determined by colorimetric MTT assays using two animal cell lines: human dermal fibroblasts and HaCaT cells. Although the M. orientalis root extract had moderate cytotoxicity in HaCaT cells at 200 microg/ml, most extracts exhibited low cytotoxicity at 200 microg/ml in both cell lines. In addition, the extracts reduced the P. acnes-induced secretion of interleukin-8 and tumor necrosis factor-alpha (TNF-alpha) in THP-1 cells, an indication of their anti-inflammatory effects. Based on these results, we suggest that M. pentaphylla, A. anomala, M. orientalis, and O. japonica are attractive acne-mitigating candidates for topical application.

Membrane filtration – Fluorescent antibody staining procedure for detecting and quantifying Renibacterium salmoninarum in coelomic fluid of Chinook Salmon (Oncorhynchus tshawytscha)

USGS Publications Warehouse

Elliott, D.G.; Barila, T.Y.

1987-01-01

We developed a rapid method for detecting and quantifying the pathogen Renibacterium salmoninarum in coelomic fluid of spring chinook salmon (Oncorhynchus tshawytscha) by concentrating the bacteria on 0.2-μm polycarbonate filters and staining them with specific fluorescein-labeled antibody. Centrifugation of samples and resuspension of the sedimented material in phosphate-buffered saline containing Triton X-100 increased the ease of filtration. Background fluorescence was reduced by counterstaining filters with Eriochrome black T. Postfiltration staining, rinsing, and counterstaining were done in the syringe-mounted filter holders, reducing handling of the filters and possible loss of bacteria. The number of bacteria detected by the filtration – fluorescent antibody technique in a broth culture of R. salmoninarum ranged from 6.7 × 107to7.6 × 107/mL and was slightly higher than that determined by plate count (9.6 × 106/mL). Increasing the sample dilution or decreasing the number of microscope fields examined generally increased the variability of filter counts of R. salmoninarum. Using the filtration – fluorescent antibody technique, we detected the bacterium in the coelomic fluid of 85% of spawning female spring chinook salmon sampled from a hatchery population.

In vitro inhibition of oral Candida albicans by chicken egg yolk antibody (IgY).

PubMed

Wang, X Z; Fan, B; Liu, L G; Hu, X Y; Li, R Y; Wei, Y; Wan, Z; Deng, X L

2008-06-01

This study was conducted to measure Candida albicans-specific chicken egg yolk antibody (IgY) inhibition of fluconazole-sensitive and resistant strains of C. albicans in order to assess potential use in the prevention and treatment of oral candidiasis. In this study, laying hens were immunized, and IgY was extracted by water dilution. The Minimal Inhibitory Concentrations (MICs) of IgY for inhibiting C. albicans growth were determined using the broth microdilution method from the CLSI M27-A2 protocol. Fluconazole (FLC) was used as the control. The results were analyzed with the chi(2) test. The anti-Candida titer of anti-C. albicans IgY was 1:12,000. The concentration of the IgY extract that effectively inhibited the growth of C. albicans was between 1.25 g/l and 5.0 g/l, and the efficacy rate was 82.98% during the observed 24-48 h time period. No correlation was recorded between the drug resistance of FLC and growth inhibition by IgY. It was concluded that anti-C. albicans IgY inhibited the growth of C. albicans in vitro and there was no correlation between the drug resistance of FLC and the growth inhibition by IgY (P > 0.99).

Prevalence of multi and pan drug resistant Pseudomonas aeruginosa with respect to ESBL and MBL in a tertiary care hospital.

PubMed

Jayakumar, S; Appalaraju, B

2007-10-01

Multi drug resistant Pseudomonas aeruginosa (MDRPA) and pan drug resistant Pseudomonas aeruginosa (PDRPA) isolates in critically ill patients are often difficult to treat. Prevalence of MDRPA and their antibiotic profile was investigated to select an appropriate empirical therapy. Moreover lack of sufficient data on prevalence of PDRPA in tertiary care hospitals indicated the need for this study. Pseudomonas aeruginosa was isolated in 245 patients over a period of one and half years from various clinical materials and their antibiotic profile was determined. Minimum inhibitory concentration (MIC) for Imipenem and Meropenam was determined by broth dilution method. Phenotypic confirmation test and EDTA double disk synergy test was used to detect Extended spectrum a-lactamase (ESBL) and Metallo-a-lactamase (MBL) producers respectively. Out of 245 isolates, 54 strains (22 %) and 11 strains (4%) were found to be MDRPA and PDRPA respectively. Carbapenem resistant isolates showed MICs ranging from 16 to > 64 microg/ml. Thirty eight strains (15.5%) were ESBL producers and six (54.5%) among 11 PDRPA were MBL producers. Prevalence of MDR and PDR isolates of Pseudomonas aeruginosa was found to be 22% and 4% respectively, which is less compared to other studies. Majority of the PDRPA isolates were MBL producers which have propensity to spread to other bacteria.

Essential Oils from Ugandan Aromatic Medicinal Plants: Chemical Composition and Growth Inhibitory Effects on Oral Pathogens

PubMed Central

Ocheng, Francis; Bwanga, Freddie; Joloba, Moses; Softrata, Abier; Azeem, Muhammad; Pütsep, Katrin; Borg-Karlson, Anna-Karin; Obua, Celestino; Gustafsson, Anders

2015-01-01

The study assessed the growth inhibitory effects of essential oils extracted from ten Ugandan medicinal plants (Bidens pilosa, Helichrysum odoratissimum, Vernonia amygdalina, Hoslundia opposita, Ocimum gratissimum, Cymbopogon citratus, Cymbopogon nardus, Teclea nobilis, Zanthoxylum chalybeum, and Lantana trifolia) used traditionally in the management of oral diseases against oral pathogens. Chemical compositions of the oils were explored by GC-MS. Inhibitory effects of the oils were assessed on periodontopathic Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans and cariogenic Streptococcus mutans and Lactobacillus acidophilus using broth dilution methods at concentrations of 1%, 0.1%, and 0.01%. The most sensitive organism was A. actinomycetemcomitans. Its growth was markedly inhibited by six of the oils at all the concentrations tested. Essential oil from C. nardus exhibited the highest activity with complete growth inhibition of A. actinomycetemcomitans and P. gingivalis at all the three concentrations tested, the major constituents in the oil being mainly oxygenated sesquiterpenes. Most of the oils exhibited limited effects on L. acidophilus. We conclude that essential oils from the studied plants show marked growth inhibitory effects on periodontopathic A. actinomycetemcomitans and P. gingivalis, moderate effects on cariogenic S. mutans, and the least effect on L. acidophilus. The present study constitutes a basis for further investigations and development of certain oils into alternative antiplaque agents. PMID:26170872

Blad-containing oligomer: a novel fungicide used in crop protection as an alternative treatment for tinea pedis and tinea versicolor.

PubMed

Carreira, Alexandra; Ferreira, João Boavida; Pereira, Iliana; Ferreira, João; Filipe, Paulo; Ferreira, Ricardo Boavida; Monteiro, Sara

2018-02-01

The lack of novel antifungal drugs and the increasing incidence and severity of fungal infections are major concerns worldwide. Herein, we tested the activity of the Blad-containing oligomer (BCO), a new antifungal molecule already in use for agriculture, on Malassezia spp. and dermatophytes, the causal agents of human tinea versicolor and tinea pedis. Given the lack of a standard method for Malassezia susceptibility testing and the plethora of published methods, we also developed an improved method for this genus. The efficacy of BCO was assessed in vitro and compared to that of the drugs currently utilized in the treatment of tinea versicolor (fluconazole and itraconazole) and tinea pedis (itraconazole and terbinafine). For dermatophytes, the standard microdilution broth-based method was used, with small adjustments, and several broth formulations and inocula sizes were tested to develop an improved susceptibility method for Malassezia spp. We successfully developed a microdilution broth-based method with considerable advantages over other available methods, and used it for all in vitro susceptibility tests of Malassezia spp. isolates. We report that, on a molar basis, BCO was more effective than fluconazole or itraconazole on most strains of Malassezia spp. isolated from clinical samples (n=29). By contrast, BCO was less effective than itraconazole or terbinafine on the common dermatophytes Trichophyton rubrum and Trichophyton interdigitale. These data place BCO as a promising drug for the treatment of Malassezia-associated skin diseases. Further in vivo studies are now required to ascertain its applicability in the clinical setting.

Development of a Novel Listeria Enrichment Broth for the Isolation of Pathogenic Listeria.

PubMed

Liu, Dongxin; Wang, Yan; Wang, Yi; Zhang, Lu; Luo, Lijuan; Liu, Kai; Ye, Changyun

2017-10-01

Listeriosis, the disease caused by pathogenic Listeria species, can present severe symptoms in susceptible people. The goal of this study was to develop a novel enrichment broth, Listeria allose enrichment broth (LAEB), to improve isolation of Listeria monocytogenes and Listeria ivanovii from samples through incorporating a specific carbohydrate and reducing inhibitor concentrations. Other coexisting bacteria, particularly Listeria innocua, can interfere with the isolation of pathogenic Listeria in such ways as overgrowth of L. innocua and the generation of inhibitory metabolites. The incorporation of allose into the novel LAEB was effective for slowing the growth of L. innocua and other nontarget microorganisms. We determined that 35°C and pH 7.0 under aerobic conditions are optimal for Listeria growth in this medium. The novelty of the use of LAEB is the single enrichment procedure at 35°C for 24 h, obviating the need for a secondary enrichment medium. In 50 simulated samples, the sensitivity of the LAEB method (86%) was higher than that of the International Organization for Standardization (EN ISO) method (70%). In 142 naturally contaminated samples tested, the isolation rate for pathogenic Listeria with the LAEB method was 26.0% (37 of 142 samples), which was significantly higher than the 17.6% (25 of 142 samples) for the EN ISO method. Higher isolation rates and a quicker and easier protocol make the novel LAEB method an appropriate alternative for the isolation of pathogenic Listeria.

The influence of dissolved oxygen level and medium on biofilm formation by Campylobacter jejuni.

PubMed

Teh, Amy Huei Teen; Lee, Sui Mae; Dykes, Gary A

2017-02-01

Campylobacter jejuni survival in aerobic environments has been suggested to be mediated by biofilm formation. Biofilm formation by eight C. jejuni strains under both aerobic and microaerobic conditions in different broths (Mueller-Hinton (MH), Bolton and Brucella) was quantified. The dissolved oxygen (DO) content of the broths under both incubation atmospheres was determined. Biofilm formation for all strains was highest in MH broth under both incubation atmospheres. Four strains had lower biofilm formation in MH under aerobic as compared to microaerobic incubation, while biofilm formation by the other four strains did not differ under the 2 atm. Two strains had higher biofilm formation under aerobic as compared to microaerobic atmospheres in Bolton broth. Biofilm formation by all other strains in Bolton, and all strains in Brucella broth, did not differ under the 2 atm. Under aerobic incubation DO levels in MH > Brucella > Bolton broth. Under microaerobic conditions levels in MH = Brucella > Bolton broth. Levels of DO in MH and Brucella broth were lower under microaerobic conditions but those of Bolton did not differ under the 2 atm. Experimental conditions and especially the DO of broth media confound previous conclusions drawn about aerobic biofilm formation by C. jejuni. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exposure to Metronidazole In Vivo Readily Induces Resistance in Helicobacter pylori and Reduces the Efficacy of Eradication Therapy in Mice

PubMed Central

Jenks, Peter J.; Labigne, Agnes; Ferrero, Richard L.

1999-01-01

The Helicobacter pylori SS1 mouse model was used to characterize the development of resistance in H. pylori after treatment with metronidazole monotherapy and to examine the effect of prior exposure to metronidazole on the efficacy of a metronidazole-containing eradication regimen. Mice colonized with the metronidazole-sensitive H. pylori SS1 strain were treated for 7 days with either peptone trypsin broth or the mouse equivalent of 400 mg of metronidazole once a day or three times per day (TID). In a separate experiment, H. pylori-infected mice were administered either peptone trypsin broth or the mouse equivalent of 400 mg of metronidazole TID for 7 days, followed 1 month later by either peptone trypsin broth or the mouse equivalent of 20 mg of omeprazole, 250 mg of clarithromycin, and 400 mg of metronidazole twice a day for 7 days. At least 1 month after the completion of treatment, the mice were sacrificed and their stomachs were cultured for H. pylori. The susceptibilities of isolates to metronidazole were assessed by agar dilution determination of the MICs. Mixed populations of metronidazole-resistant and -sensitive strains were isolated from 70% of mice treated with 400 mg of metronidazole TID. The ratio of resistant to sensitive strains was 1:100, and the MICs for the resistant strains varied from 8 to 64 μg/ml. In the second experiment, H. pylori was eradicated from 70% of mice treated with eradication therapy alone, compared to 25% of mice pretreated with metronidazole (P < 0.01). Mice still infected after treatment with metronidazole and eradication therapy contained mixed populations of metronidazole-resistant and -sensitive isolates in a ratio of 1:25. These results demonstrate that H. pylori readily acquires resistance to metronidazole in vivo and that prior exposure of the organism to metronidazole is associated with failure of eradication therapy. H. pylori-infected mice provide a suitable model for the study of resistance mechanisms in H. pylori and will be useful in determining optimal regimens for the eradication of resistant strains. PMID:10103180

Dilutions Made Easy.

ERIC Educational Resources Information Center

Kamin, Lawrence

1996-01-01

Presents problems appropriate for high school and college students that highlight dilution methods. Promotes an understanding of dilution methods in order to prevent the unnecessary waste of chemicals and glassware in biology laboratories. (JRH)

Development of a rapid immunochromatographic assay to detect contamination of raw oysters with enteropathogenic Vibrio parahaemolyticus.

PubMed

Sakata, Junko; Yonekita, Taro; Kawatsu, Kentaro

2018-01-02

Thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH) are major virulence factors of enteropathogenic Vibrio parahaemolyticus. TDH and TRH are bacterial exotoxins, and their presence in culture medium serves as a specific marker for detecting this significant pathogen. Here, we developed and evaluated an immunochromatographic assay (TDH/TRH-ICA) to simultaneously or individually detect TDH and TRH. The TDH/TRH-ICA detected TDH in all broth cultures of 47 V. parahaemolyticus strains carrying tdh. The genes encoding TRH are classified as variants trh1 and trh2, and TRH was detected in all broth cultures of 25 V. parahaemolyticus strains carrying trh1 and certain proportion (5/31) of broth cultures of V. parahaemolyticus strains carrying trh2. In contrast, TDH and TRH were not detected in broth cultures of 12 non-enteropathogenic V. parahaemolyticus strains without tdh and trh. It was difficult to detect TRH2 using the TDH/TRH-ICA. However, TRH2 may not serve as a suitable marker for detecting enteropathogenic V. parahaemolyticus, and evidence indicates that TRH2 may not contribute to enteropathogenesis. Further, a screening method using a combination of TDH/TRH-ICA and SPP medium supplemented with 1.5% NaCl (modified-SPP medium) detected oyster samples artificially spiked with 1.1-22 colony-forming units of enteropathogenic V. parahaemolyticus per 25g of oysters within approximately 8.5h, including the enrichment culture. The assay may serve as a method that facilitates the rapid and easy detection of raw oysters contaminated with enteropathogenic V. parahaemolyticus. Copyright © 2017. Published by Elsevier B.V.

In vitro antimicrobial activity of benzoyl peroxide against Propionibacterium acnes assessed by a novel susceptibility testing method.

PubMed

Okamoto, Kazuaki; Ikeda, Fumiaki; Kanayama, Shoji; Nakajima, Akiko; Matsumoto, Tatsumi; Ishii, Ritsuko; Umehara, Masatoshi; Gotoh, Naomasa; Hayashi, Naoki; Iyoda, Takako; Matsuzaki, Kaoru; Matsumoto, Satoru; Kawashima, Makoto

2016-06-01

Benzoyl peroxide (BPO), a therapeutic agent for acne vulgaris, was assessed for in vitro antimicrobial activity against Propionibacterium acnes using a novel broth microdilution testing that improved BPO solubility. We searched for a suitable culture medium to measure the minimum inhibitory concentration (MIC) of BPO against P. acnes and finally found the Gifu anaerobic medium (GAM) broth supplemented with 0.1(v/v)% glycerol and 2(v/v)% Tween 80, in which BPO dissolved up to 1250 μg/mL and P. acnes grew well. The MICs and minimum bactericidal concentrations (MBCs) of BPO against 44 clinical isolates of P. acnes collected from Japanese patients with acne vulgaris were determined by our testing method using the supplemented GAM broth. The MICs of BPO were 128 or 256 μg/mL against all isolates of P. acnes regardless of susceptibility to nadifloxacin or clindamycin. The MBCs of BPO were also 128 or 256 μg/mL against the same isolates. Moreover, BPO at the MIC showed a rapid bactericidal activity against P. acnes ATCC11827 in time-kill assay. In conclusion, we could develop a novel assay for the MIC and MBC determinations of BPO against P. acnes, which is reliable and reproducible as a broth microdilution testing and the present results suggest that BPO has a potent bactericidal activity against P. acnes. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

In vitro susceptibility of bovine mastitis pathogens to a combination of penicillin and framycetin: development of interpretive criteria for testing by broth microdilution and disk diffusion.

PubMed

Pillar, C M; Stoneburner, A; Shinabarger, D L; Abbeloos, E; Goby, L; Bradley, Andrew J

2014-10-01

Dry cow therapy is an important part of mastitis control. This therapy typically consists of an antibiotic or antibiotics administered at a single dose by intramammary infusion at dry off to treat or prevent infection by prevalent mastitis pathogens. A combination dry cow therapy consisting of the active components penicillin and framycetin is currently used in several countries. Despite its use, standardized methods for the susceptibility testing of this combination against mastitis pathogens have not been established. In this study, which used Clinical and Laboratory Standards Institute methodology, preliminary interpretive criteria for the broth microdilution minimum inhibitory concentration (MIC) testing of mastitis pathogens to penicillin combined with framycetin (2:1 wt/wt) were established based on the amount of drug achieved and maintained postadministration in the udder. Based on resulting MIC distributions of recent veterinary field isolates and a subset of isolates preselected for resistance to β-lactams or aminoglycosides and concentrations achieved postadministration, criteria for broth microdilution testing of the combination (susceptible, intermediate, resistant in micrograms per milliliter) were set as follows: Escherichia coli ≤8/4, 16/8, ≥32/16; Staphylococcus spp. ≤2/1, 4/2-8/4, >16/8; Streptococcus uberis and Streptococcus dysgalactiae <0.25/0.12, 0.5/0.25-2/1, >4/2. A disk diffusion test using disks containing 100 μg of framycetin and 10 IU of penicillin was also developed, and preliminary interpretive criteria (susceptible, intermediate, resistant in millimeters) were set based on correlation to broth MIC values and the minimization of interpretive errors between isolates tested concurrently by broth microdilution and disk diffusion as follows: E. coli ≥18, 16-17, ≤15; Staphylococcus spp. ≥21, 18-20, ≤17; Strep. uberis and Strep. dysgalactiae ≥21, 19-20, ≤18. In addition, ranges for the quality control of the testing of this combination by both broth microdilution and disk diffusion are provided. Based on these criteria and recent veterinary mastitis isolates, 96.0/96.8% of E. coli, 93.7/89.1% of Staph. aureus, 94.6/96.4% coagulase-negative staphylococci, 94.5/97.0% of Strep. uberis, and 96.7/100.0% Strep. dysgalactiae were susceptible to the combination by broth microdilution or disk diffusion, respectively. The availability of these methods will allow for the susceptibility testing of clinical isolates in the field and will also provide a way to monitor for resistance development as this combination is used going forward. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Antibacterial and Antifungal Activity of Holothuria leucospilota Isolated From Persian Gulf and Oman Sea

PubMed Central

Adibpour, Neda; Nasr, Farhad; Nematpour, Fatemeh; Shakouri, Arash; Ameri, Abdolghani

2014-01-01

Background: Emergence of antimicrobial resistance toward a number of conventional antibiotics has triggered the search for antimicrobial agents from a variety of sources including the marine environment. Objectives: The aim of this study was to evaluate the antimicrobial potential of Holothuria leucospilota from Qeshm and Kharg Islands against some selected bacteria and fungi. Materials and Methods: In this investigation, sea cucumbers from two coastal cities of Persian Gulf were collected in March and May 2011 and identified by the scale method according to the food and agriculture organization of the United Nations. Antibacterial activity of hydroalcoholic extracts of the body wall, cuvierian organs and coelomic fluid, methanol, chloroform, and n-hexane extracts of the body wall were evaluated by the spot test. In addition, their antifungal activity was assessed by the broth dilution method. Results: The displayed effect was microbiostatic at concentrations of 1000 and 2000 µg/mL rather than microbicidal. The highest activity of hydroalcoholic extracts was exhibited by body wall, cuvierian organs and coelomic fluid against Escherichia coli, Salmonella typhi, Staphylococcus aureus and Pseudomonas aeruginosa; Aspergillus niger, A. fumigatus, A. flavus and A. brasilensis. However, none of the methanol, chloroform and n-haxane extracts showed appreciable effects against Shigella dysenteriae, Proteus vulgaris, Bacillus cereus, S. epidermidis and Candida albicans. Moreover, cuvierian organs did not possess any antifungal potential. Conclusions: Our data indicated that water-methanol extracts from the body wall of H. leucospilota possess antibacterial and antifungal activity. However, additional and in-depth studies are required to isolate and identify the active component(s). PMID:25147657

Rheology and hydrodynamic properties of Tolypocladium inflatum fermentation broth and its simulation.

PubMed

Benchapattarapong, N; Anderson, W A; Bai, F; Moo-Young, M

2005-07-01

A physico-chemical, two phase simulated pseudoplastic fermentation (SPF) broth was investigated in which Solka Floc cellulose fibre was used to simulate the filamentous biomass, and a mixture of 0.1% (w/v) carboxymethyl cellulose (CMC) and 0.15 M aqueous sodium chloride was used to simulate the liquid fraction of the fermentation broth. An investigation of the rheological behaviour and hydrodynamic properties of the SPF broth was carried out, and compared to both a fungal Tolypocladium inflatum fermentation broth and a CMC solution in a 50 L stirred tank bioreactor equipped with conventional Rushton turbines. The experimental data confirmed the ability of the two phase SPF broth to mimic both the T. inflatum broth bulk rheology as well as the mixing and mass transfer behaviour. In contrast, using a homogeneous CMC solution with a similar bulk rheology to simulate the fermentation resulted in a significant underestimation of the mass transfer and mixing times. The presence of the solid phase and its microstructure in the SPF broth appear to play a significant role in gas holdup and bubble size, thus leading to the different behaviours. The SPF broth seems to be a more accurate simulation fluid that can be used to predict the bioreactor mixing and mass transfer performance in filamentous fermentations, in comparison with CMC solutions used in some previous studies.

Synergistic antibacterial effect of apigenin with β-lactam antibiotics and modulation of bacterial resistance by a possible membrane effect against methicillin resistant Staphylococcus aureus.

PubMed

Akilandeswari, K; Ruckmani, K

2016-12-30

Methicillin-resistant Staphylococcus aureus (MRSA) infections are easily spread among infected patients, where resistance has dramatically increased resulted in serious health issues. Therefore, there is a need to develop alternative natural or combination drug therapies. Apigenin (AP) is a natural poly phenolic flavonoid has been found to possess many beneficial biological actions. The aim of this study was to investigate the anti-MRSA efficacy and synergistic effect of apigenin (AP) and in combination with ampicillin (AM) and ceftriaxone (CEF). The antibacterial activity of apigenin was assessed by the broth macro dilution, checkerboard micro dilution method and time-kill assay.  The mode of action was studied by outer and inner membrane permeabilisation assays, scanning electron microscopy and transmission electron microscopy. The minimum inhibitory concentration (MIC) of apigenin against gram positive and gram negative strain ranged from 32.5 to 62.5µg/ml. In checkerboard method apigenin markedly reduced the MIC of the antibiotics ampicillin 800 µg/ml shifted to 107 µg/ml (AM+AP) and ceftriaxone 58 µg/ml shifted to 2.6 µg/ml (CEF+AP) against MRSA. The synergistic activity of ampicillin and ceftriaxone plus apigenin combinations with FIC indices (CI) between 0.18-0.47. The modulation of methicillin-resistance by apigenin significantly enhanced the activities of ampicillin and ceftriaxone. The result of time-kill assays of the two drug combinations AM +AP and CEF+AP against MRSA showed significant inhibitory effect and reduced the colony count by approximately 99% after 8 h The results for outer membrane (OM) and inner membrane (IM) permeabilization showed that ampicillin and ceftriaxone in combination with apigenin damaged MRSA cytoplasmic membrane and caused subsequent leakage of intracellular constituents. Electron microscopy clearly showed that the above said combination also caused marked morphological damage of cell wall, cell shape and plasma membrane of this strain. From these results, it can be concluded that apigenin has the synergistic effect with ampicillin and ceftriaxone to reverse bacterial resistance against MRSA.

Antimicrobial Activities of European Propolis Collected from Various Geographic Origins Alone and in Combination with Antibiotics

PubMed Central

AL-Ani, Issam; Zimmermann, Stefan; Reichling, Jürgen

2018-01-01

Background: Propolis consists of a complex mixture of resinous substances collected by honeybees from different plant sources. The objective of this study was to investigate the chemical composition, biological activities, and synergistic properties with antibiotics of propolis samples collected from various geographic origins (Germany, Ireland, and Czech Republic). Methods: The chemical composition of the propolis was analyzed by Gas Liquid Chromatography-Mass Spectrometry (GLC-MS) and High-performance liquid chromatography (HPLC). The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were evaluated by the standard broth microdilution method, while synergistic interactions were assessed by checkerboard dilution and time-kill curve assays. Results: HPLC and GLC-MS analyses revealed that ethanol extract of propolis (EEP) and water extracts of propolis (WEP) contained more than 100 different phytochemicals. The most abundant compounds were aromatic alcohols, aromatic acids, cinnamic acid and its esters, fatty acids, and flavanone (chrysin). Czech propolis showed the highest phenolic content (129.83 ± 5.9 mg CAE/g) followed by Irish propolis and German propolis. Furthermore, Irish propolis exhibited the highest value of total flavonoid content (2.86 ± 0.2 mg QE/g) and antioxidant activity (IC50 = 26.45 µg/mL). All propolis samples showed moderate antibacterial effect against Gram-positive microorganisms with MIC ranging from 0.08 mg/mL to 2.5 mg/mL. Moreover, EEP exhibited moderate activity against Gram-negative bacteria with MIC between 0.6 mg/mL to 5 mg/mL. In addition, EEP displayed moderate antifungal activity (MIC values between 0.6–2.5 mg/mL). The results obtained from time kill-kinetic assay and checkerboard dilution test of two-drug combinations between EEP and antibiotics such as vancomycin, oxacillin, and levofloxacin indicate mainly synergistic interactions against drug-resistant microbial pathogens including MRSA and VRE. Conclusions: The propolis extract synergistically enhanced the efficacy of antibiotics, especially those acting on cell wall synthesis (vancomycin and oxacillin) against drug-resistant microorganisms. PMID:29301368

Antimicrobial and Genotoxicity Effects of Zero-valent Iron Nanoparticles

PubMed Central

Barzan, Elham; Mehrabian, Sedigheh; Irian, Saeed

2014-01-01

Background: In a world of nanotechnology, the first concern is the potential environmental impact of nanoparticles. An efficient way to estimate nanotoxicity is to monitor the responses of bacteria exposed to these particles. Objectives: The current study explored the antimicrobial properties of nZVI (zero-valent Iron nanoparticles) on the Gram-negative bacterial systems Erwinia amylovora, Xanthomonas oryzae and the Gram-positive bacterial systems Bacillus cereus and Streptomyces spp. The genotoxicity potential of nZVI was also assayed. Materials and Methods: The toxicity of nZVI was tested by two different methods: Growing bacteria in liquid (broth dilution) and agar media (challenge test) containing different nZVI concentrations for 24-72 hours. The genotoxicity of nZVI was assessed using the preincubation version of the Ames test. Results: The lowest concentrations of nZVI that inhibited the visible growth (MIC) of E. amylovora, X. oryzae, B. cereus and Streptomyces spp. were 625, 550, 1250 and 1280 ppm, respectively. The minimum bactericidal concentration (MBC) for E. amylovora and X. oryzae were 10,000 and 5,000 ppm of nZVI, respectively. MBC was not observed for the Gram positive bacteria. No bacteriostatic and bactericidal effects were observed for oxidized nZVI. Mutant frequency did not increase according to the vehicle control at the concentrations assayed, indicating a lack of mutagenicity associated with nZVI. Conclusions: nZVI nanoparticles are not mutagenic at low concentrations, therefore they can be used without detrimental effects on soil bacteria. PMID:25147712

Laser scanning confocal microscopy and laser tweezers based experiments to understand dentine-bacteria interactions

NASA Astrophysics Data System (ADS)

Peng, Sum Chee; Mohanty, Samarendra; Gupta, P. K.; Kishen, Anil

2007-02-01

Failure of endodontic treatment is commonly due to Enterococcal infection. In this study influence of chemical treatments of type-I collagen membrane by chemical agents commonly used in endodontic treatment on Enterococcus faecalis cell adherence was evaluated. In order to determine the change in number of adhering bacteria after chemical treatment, confocal laser scanning microscopy was used. For this, overnight culture of E faecalis in All Culture broth was applied to chemically treated type-I collagen membrane. It was found that Ca(OH) II treated groups had statistically significant (p value=0.05) increase in population of bacteria adherence. The change in adhesion force between bacteria and collagen was determined by using optical tweezers (1064 nm). For this experiment, Type-I collagen membrane was soaked for 5 mins in a media that contained 50% all culture media and 50% saturated Ca(OH) II . The membrane was spread on the coverslip, on which diluted bacterial suspension was added. The force of laser tweezers on the bacteria was estimated at different trap power levels using viscous drag method and trapping stiffness was calculated using Equipartition theorem method. Presence of Ca(OH) II was found to increase the cell-substrate adherence force from 0.38pN to >2.1pN. Together, these experiments show that it was highly probable that the increase in adherence to collagen was due to a stronger adhesion in the presence of Ca (OH) II.

Colloidal silver: a novel treatment for Staphylococcus aureus biofilms?

PubMed

Goggin, Rachel; Jardeleza, Camille; Wormald, Peter-John; Vreugde, Sarah

2014-03-01

Colloidal silver is an alternative medicine consisting of silver particles suspended in water. After using this solution as a nasal spray, the symptoms of a previously recalcitrant Staphylococcus aureus (S. aureus)-infected chronic rhinosinusitis patient were observed to have improved markedly. The aim of this study was to determine whether colloidal silver has any direct bactericidal effects on these biofilms in vitro. S. aureus biofilms were grown from the ATCC 25923 reference strain on Minimum Biofilm Eradication Concentration (MBEC) device pegs, and treated with colloidal silver. Concentrations tested ranged from 10 to 150 μL colloidal silver diluted to 200 μL with sterile water in 50 μL cerebrospinal fluid (CSF) broth. Control pegs were exposed to equivalent volumes of CSF broth and sterile water. The sample size was 4 biomass values per treatment or control group. Confocal scanning laser microscopy and COMSTAT software were used to quantify biofilms 24 hours after treatment. Significant differences from control were found for all concentrations tested bar the lowest of 10 μL colloidal silver in 200 μL. At 20 μL colloidal silver, the reduction in biomass was 98.9% (mean difference between control and treatment = -4.0317 μm(3) /μm(2) , p < 0.0001). A maximum biomass reduction of 99.8% was reached at both 100 and 150 μL colloidal silver (mean differences = -4.0681 and -4.0675μm(3) /μm(2) , respectively, p < 0.0001). Colloidal silver directly attenuates in vitro S. aureus biofilms. © 2014 ARS-AAOA, LLC.

Implications in studies of environmental risk assessments: Does culture medium influence the results of toxicity tests of marine bacteria?

PubMed

Díaz-García, Alejandra; Borrero-Santiago, Ana R; Riba, Inmaculada

2018-04-14

Two marine bacterial populations (Roseobacter sp. and Pseudomonas litoralis) were exposed to different concentrations of zinc (300, 625, 1250, 2000, 2500 and 5000 mg L -1 ) and cadmium (75, 250, 340, 500 and 1000 mg L -1 ) using two culture media (full nutrient Marine Broth 2216 "MB" and 1:10 (vol/vol) dilution with seawater of Marine Broth 2216 "MB SW "), in order to assess population responses depending on the culture medium and also potential adverse effects associated with these two metals. Different responses were found depending on the culture medium (Bacterial abundance (cells·mL -1 ), growth rates (μ, hours -1 ), and production of Extracellular Polysaccharides Substances (EPS) (μg glucose·cells -1 ). Results showed negative effects in both strains after the exposure to Zn treatments. Both strains showed highest metal sensitivity at low concentrations using both culture media. However, different results were found when exposing the bacterial populations to Cd treatments depending on the culture medium. Highest toxicity was observed using MB at low levels of Cd concentrations, whereas MB SW showed toxicity to bacteria at higher concentrations of Cd. Results not only showed adverse effects on Roseobacter sp. and Pseudomonas litoralis associated with the concentration of Zn and Cd, but also confirm that depending on the culture medium results can differ. This work suggests MB SW as an adequate culture medium to study metal toxicity bioassays in order to predict realistic effects on marine bacterial populations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Partial purification of saccharifying and cell wall-hydrolyzing enzymes from malt in waste from beer fermentation broth.

PubMed

Khattak, Waleed Ahmad; Kang, Minkyung; Ul-Islam, Mazhar; Park, Joong Kon

2013-06-01

A number of hydrolyzing enzymes that are secreted from malt during brewing, including cell wall-hydrolyzing, saccharide-hydrolyzing, protein-degrading, lipid-hydrolyzing, and polyphenol and thiol-hydrolyzing enzymes, are expected to exist in an active form in waste from beer fermentation broth (WBFB). In this study, the existence of these enzymes was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, after which enzyme extract was partially purified through a series of purification steps. The hydrolyzing enzyme activity was then measured under various conditions at each purification step using carboxymethyl cellulose as a substrate. The best hydrolyzing activities of partially purified enzymes were found at pH 4.5 and 50 °C in a citrate buffer system. The enzymes showed highest thermal stability at 30 °C when exposed for prolonged time. As the temperature increased gradually from 25 to 70 °C, yeast cells in the chemically defined medium with enzyme extract lost their cell wall and viability earlier than those without enzyme extract. Cell wall degradation and the release of cell matrix into the culture media at elevated temperature (45-70 °C) in the presence of enzyme extract were monitored through microscopic pictures. Saccharification enzymes from malt were relatively more active in the original WBFB than supernatant and diluted sediments. The presence of hydrolyzing enzymes from malt in WBFB is expected to play a role in bioethanol production using simultaneous saccharification and fermentation without the need for additional enzymes, nutrients, or microbial cells via a cell-free enzyme system.

Osmotic effect of honey on growth and viability of Helicobacter pylori.

PubMed

Osato, M S; Reddy, S G; Graham, D Y

1999-03-01

Honey from New Zealand and Saudi Arabia at concentrations approximating 20% (v/v) inhibit the growth of H. pylori in vitro. The anti-H. pylori effect involves both hydrogen peroxide- and non-peroxide-mediated killing mechanisms. This study was designed to determine whether the anti-H. pylori activity of honey differed regionally (honey from Texas, Iowa, and New Zealand) and to determine whether this activity was due to the presence of hydrogen peroxide. Broth dilution susceptibility tests were performed using solutions of honey prepared in BHI broth ranging in concentration from 5 to 35% (v/v) in 5% increments. Control solutions containing glucose, fructose, and combined glucose/fructose solutions in ratios of 1:1.23 were also prepared. Paired catalase controls were included in all tests. Twenty-eight clinical isolates of H. pylori were tested. Growth was determined on the basis of a plus/minus grading score. All of the solutions containing either fructose, glucose, glucose and fructose combinations, or honey were equally effective in inhibiting the growth of H. pylori. All of the isolates were inhibited by solutions containing 15% (w/v) carbohydrate. Honey solutions, with or without catalase, inhibited 24/28 isolates at a concentration of 10%, and 28/28 isolates at a concentration of 15%. In conclusion, regional differences in honey activity against H. pylori were not detected, nor was the effect of killing related to the presence of hydrogen peroxide in the honey samples. Osmotic effects were shown to be the most important parameter for killing H. pylori as all carbohydrate solutions > or = 15% (v/v) inhibited 100% of the H. pylori.

[Influence of Mueller-Hinton broth on the in vitro activities of cefuzoname, flomoxef, imipenem, and minocycline against Staphylococcus aureus].

PubMed

Fujita, S; Tonohata, A

1990-05-01

The influence of Mueller-Hinton (MH) broth (from BBL Microbiology Systems, and Difco Laboratories) of minimum inhibitory concentrations (MIC) of cefuzoname (CZON), flomoxef (FMOX), imipenem (IPM), and minocycline (MINO) for 100 strains of Staphylococcus aureus was investigated. Antibacterial activity of MINO was stronger than any other antibiotics. MICs of CZON for 16 strains (14 of 50 methicillin-resistant S. aureus (MRSA), 2 of 50 methicillin-sensitive S. aureus) were greater than or equal to 4-fold greater when tested in BBL MH broth than when tested in Difco MH broth, thus, different media altered categories of some strains (8 of 50 MRSA) from susceptible to resistant. MICs of FMOX in the BBL MH broth for 12 of 50 MRSA strains rose greater than or equal to 4-fold compared to the Difco MH broth. On the other hand, MICs of IPM and MINO were affected very little by the different brand of MH broth used.

Disentangling niche competition from grazing mortality in phytoplankton dilution experiments

PubMed Central

Weitz, Joshua S.

2017-01-01

The dilution method is the principal tool used to infer in situ microzooplankton grazing rates. However, grazing is the only mortality process considered in the theoretical model underlying the interpretation of dilution method experiments. Here we evaluate the robustness of mortality estimates inferred from dilution experiments when there is concurrent niche competition amongst phytoplankton. Using a combination of mathematical analysis and numerical simulations, we find that grazing rates may be overestimated—the degree of overestimation is related to the importance of niche competition relative to microzooplankton grazing. In response, we propose a conceptual method to disentangle the effects of niche competition and grazing by diluting out microzooplankton, but not phytoplankton. Our theoretical results suggest this revised “Z-dilution” method can robustly infer grazing mortality, regardless of the dominant phytoplankton mortality driver in our system. Further, we show it is possible to independently estimate both grazing mortality and niche competition if the classical and Z-dilution methods can be used in tandem. We discuss the significance of these results for quantifying phytoplankton mortality rates; and the feasibility of implementing the Z-dilution method in practice, whether in model systems or in complex communities with overlap in the size distributions of phytoplankton and microzooplankton. PMID:28505212

Enumeration procedure for monitoring test microbe populations on inoculated carriers in AOAC use-dilution methods.

PubMed

Tomasino, Stephen F; Fiumara, Rebecca M; Cottrill, Michele P

2006-01-01

The AOAC Use-Dilution methods do not provide procedures to enumerate the test microbe on stainless steel carriers (penicylinders) or guidance on the expected target populations of the test microbe (i.e., a performance standard). This report describes the procedures used by the U.S. Environmental Protection Agency to enumerate the test microbe (carrier counts) associated with conducting the Use-Dilution method with Staphylococcus aureus (Method 955.15) and Pseudomonas aeruginosa (Method 964.02) and the examination of historical data. The carrier count procedure involves the random selection of carriers, shearing bacterial cells from the carrier surface through sonication, and plating of serially diluted inoculum on trypticase soy agar. For each Use-Dilution test conducted, the official AOAC method was strictly followed for carrier preparation, culture initiation, test culture preparation, and carrier inoculation steps. Carrier count data from 78 Use-Dilution tests conducted over a 6-year period were compiled and analyzed. A mean carrier count of 6.6 logs (approximately 4.0 x 10(6) colony-forming units/carrier) was calculated for both S. aureus and P. aeruginosa. Of the mean values, 95% fell within +/- 2 repeatability standard deviations. The enumeration procedure and target carrier counts are desirable for standardizing the Use-Dilution methods, increasing their reproducibility, and ensuring the quality of the data.

Reverse Osmosis Processing of Organic Model Compounds and Fermentation Broths

DTIC Science & Technology

2006-04-01

AFRL-ML-TY-TP-2007-4545 POSTPRINT REVERSE OSMOSIS PROCESSING OF ORGANIC MODEL COMPOUNDS AND FERMENTATION BROTHS Robert Diltz...TELEPHONE NUMBER (Include area code) Bioresource Technology 98 (2007) 686–695Reverse osmosis processing of organic model compounds and fermentation broths...December 2005; accepted 31 January 2006 Available online 4 April 2006Abstract Post-treatment of an anaerobic fermentation broth was evaluated using a 150

Sensitivity of Direct Culture, Enrichment and PCR for Detection of Campylobacter jejuni and C. coli in Broiler Flocks at Slaughter.

PubMed

Rodgers, J D; Simpkin, E; Lee, R; Clifton-Hadley, F A; Vidal, A B

2017-06-01

Broiler chicken flocks are a significant source of Campylobacter jejuni and Campylobacter coli that result in the major public health problem of campylobacteriosis. Accurate estimates of the prevalence of both C. coli and C. jejuni in flocks would enhance epidemiological understanding, risk assessment and control options. This study combined results from a panel of 10 detection tests (direct culture, enrichment and PCR) on caecal samples from flocks at slaughter. A parallel interpretation approach was used to determine the presence of Campylobacter spp. and for C. jejuni and C. coli individually. The sample was considered positive if at least one method detected the target and this interpretation was taken to represent a 'proxy gold standard' for detection in the absence of a gold standard reference test. The sensitivity of each individual method to detect Campylobacter spp., C. jejuni and C. coli was then estimated relative to the proxy gold standard. Enrichment in adapted Exeter broth (deficient in polymyxin B) with a resuscitation step was 100% sensitive, whilst direct culture on modified charcoal cefoperazone deoxycholate agar (mCCDA) was highly sensitive (97.9%). Enrichment methods using Preston broth and Bolton broth were significantly less sensitive. Enrichment in Exeter broth promoted the recovery of C. jejuni, whilst enrichment in Bolton broth favoured C. coli. A RT-PCR detection test could identify 80% of flocks that were co-colonised with both species. This study found that 76.3% (n = 127) of flocks were colonised with Campylobacter spp. The majority (95.9%) of Campylobacter-positive flocks were colonised with C. jejuni; however, approximately one-third of positive flocks were simultaneously colonised with both C. jejuni and C. coli. The findings highlight the impact of different detection methodologies on the accuracy of the estimated incidence of both C. jejuni and C. coli entering the abattoir within broiler flocks and the associated public health risks. © 2016 Crown copyright. Zoonoses and Public Health published by Blackwell Verlag GmbH. This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

Paradigm Diagnostics Salmonella Indicator Broth (PDX-SIB) for detection of Salmonella on selected environmental surfaces.

PubMed

Olstein, Alan; Griffith, Leena; Feirtag, Joellen; Pearson, Nicole

2013-01-01

The Paradigm Diagnostics Salmonella Indicator Broth (PDX-SIB) is intended as a single-step selective enrichment indicator broth to be used as a simple screening test for the presence of Salmonella spp. in environmental samples. This method permits the end user to avoid multistep sample processing to identify presumptively positive samples, as exemplified by standard U.S. reference methods. PDX-SIB permits the outgrowth of Salmonella while inhibiting the growth of competitive Gram-negative and -positive microflora. Growth of Salmonella-positive cultures results in a visual color change of the medium from purple to yellow when the sample is grown at 37 +/- 1 degree C. Performance of PDX-SIB has been evaluated in five different categories: inclusivity-exclusivity, methods comparison, ruggedness, lot-to-lot variability, and shelf stability. The inclusivity panel included 100 different Salmonella serovars, 98 of which were SIB-positive during the 30 to 48 h incubation period. The exclusivity panel included 33 different non-Salmonella microorganisms, 31 of which were SIB-negative during the incubation period. Methods comparison studies included four different surfaces: S. Newport on plastic, S. Anatum on sealed concrete, S. Abaetetuba on ceramic tile, and S. Typhimurium in the presence of 1 log excess of Citrobacter freundii. Results of the methods comparison studies demonstrated no statistical difference between the SIB method and the U.S. Food and Drug Administration-Bacteriological Analytical Manual reference method, as measured by the Mantel-Haenszel Chi-square test. Ruggedness studies demonstrated little variation in test results when SIB incubation temperatures were varied over a 34-40 degrees C range. Lot-to-lot consistency results suggest no detectable differences in manufactured goods using two reference Salmonella serovars and one non-Salmonella microorganism.

An insight into the isolation, enumeration, and molecular detection of Listeria monocytogenes in food

PubMed Central

Law, Jodi Woan-Fei; Ab Mutalib, Nurul-Syakima; Chan, Kok-Gan; Lee, Learn-Han

2015-01-01

Listeria monocytogenes, a foodborne pathogen that can cause listeriosis through the consumption of food contaminated with this pathogen. The ability of L. monocytogenes to survive in extreme conditions and cause food contaminations have become a major concern. Hence, routine microbiological food testing is necessary to prevent food contamination and outbreaks of foodborne illness. This review provides insight into the methods for cultural detection, enumeration, and molecular identification of L. monocytogenes in various food samples. There are a number of enrichment and plating media that can be used for the isolation of L. monocytogenes from food samples. Enrichment media such as buffered Listeria enrichment broth, Fraser broth, and University of Vermont Medium (UVM) Listeria enrichment broth are recommended by regulatory agencies such as Food and Drug Administration-bacteriological and analytical method (FDA-BAM), US Department of Agriculture-Food and Safety (USDA-FSIS), and International Organization for Standardization (ISO). Many plating media are available for the isolation of L. monocytogenes, for instance, polymyxin acriflavin lithium-chloride ceftazidime aesculin mannitol, Oxford, and other chromogenic media. Besides, reference methods like FDA-BAM, ISO 11290 method, and USDA-FSIS method are usually applied for the cultural detection or enumeration of L. monocytogenes. most probable number technique is applied for the enumeration of L. monocytogenes in the case of low level contamination. Molecular methods including polymerase chain reaction, multiplex polymerase chain reaction, real-time/quantitative polymerase chain reaction, nucleic acid sequence-based amplification, loop-mediated isothermal amplification, DNA microarray, and next generation sequencing technology for the detection and identification of L. monocytogenes are discussed in this review. Overall, molecular methods are rapid, sensitive, specific, time- and labor-saving. In future, there are chances for the development of new techniques for the detection and identification of foodborne with improved features. PMID:26579116

An insight into the isolation, enumeration, and molecular detection of Listeria monocytogenes in food.

PubMed

Law, Jodi Woan-Fei; Ab Mutalib, Nurul-Syakima; Chan, Kok-Gan; Lee, Learn-Han

2015-01-01

Listeria monocytogenes, a foodborne pathogen that can cause listeriosis through the consumption of food contaminated with this pathogen. The ability of L. monocytogenes to survive in extreme conditions and cause food contaminations have become a major concern. Hence, routine microbiological food testing is necessary to prevent food contamination and outbreaks of foodborne illness. This review provides insight into the methods for cultural detection, enumeration, and molecular identification of L. monocytogenes in various food samples. There are a number of enrichment and plating media that can be used for the isolation of L. monocytogenes from food samples. Enrichment media such as buffered Listeria enrichment broth, Fraser broth, and University of Vermont Medium (UVM) Listeria enrichment broth are recommended by regulatory agencies such as Food and Drug Administration-bacteriological and analytical method (FDA-BAM), US Department of Agriculture-Food and Safety (USDA-FSIS), and International Organization for Standardization (ISO). Many plating media are available for the isolation of L. monocytogenes, for instance, polymyxin acriflavin lithium-chloride ceftazidime aesculin mannitol, Oxford, and other chromogenic media. Besides, reference methods like FDA-BAM, ISO 11290 method, and USDA-FSIS method are usually applied for the cultural detection or enumeration of L. monocytogenes. most probable number technique is applied for the enumeration of L. monocytogenes in the case of low level contamination. Molecular methods including polymerase chain reaction, multiplex polymerase chain reaction, real-time/quantitative polymerase chain reaction, nucleic acid sequence-based amplification, loop-mediated isothermal amplification, DNA microarray, and next generation sequencing technology for the detection and identification of L. monocytogenes are discussed in this review. Overall, molecular methods are rapid, sensitive, specific, time- and labor-saving. In future, there are chances for the development of new techniques for the detection and identification of foodborne with improved features.

Activities of Fluconazole, Caspofungin, Anidulafungin, and Amphotericin B on Planktonic and Biofilm Candida Species Determined by Microcalorimetry

PubMed Central

Maiolo, Elena Maryka; Furustrand Tafin, Ulrika; Borens, Olivier

2014-01-01

We investigated the activities of fluconazole, caspofungin, anidulafungin, and amphotericin B against Candida species in planktonic form and biofilms using a highly sensitive assay measuring growth-related heat production (microcalorimetry). C. albicans, C. glabrata, C. krusei, and C. parapsilosis were tested, and MICs were determined by the broth microdilution method. The antifungal activities were determined by isothermal microcalorimetry at 37°C in RPMI 1640. For planktonic Candida, heat flow was measured in the presence of antifungal dilutions for 24 h. Candida biofilm was formed on porous glass beads for 24 h and exposed to serial dilutions of antifungals for 24 h, and heat flow was measured for 48 h. The minimum heat inhibitory concentration (MHIC) was defined as the lowest antifungal concentration reducing the heat flow peak by ≥50% (≥90% for amphotericin B) at 24 h for planktonic Candida and at 48 h for Candida biofilms (measured also at 24 h). Fluconazole (planktonic MHICs, 0.25 to >512 μg/ml) and amphotericin B (planktonic MHICs, 0.25 to 1 μg/ml) showed higher MHICs than anidulafungin (planktonic MHICs, 0.015 to 0.5 μg/ml) and caspofungin (planktonic MHICs, 0.125 to 0.5 μg/ml). Against Candida species in biofilms, fluconazole's activity was reduced by >1,000-fold compared to its activity against the planktonic counterparts, whereas echinocandins and amphotericin B mainly preserved their activities. Fluconazole induced growth of planktonic C. krusei at sub-MICs. At high concentrations of caspofungin (>4 μg/ml), paradoxical growth of planktonic C. albicans and C. glabrata was observed. Microcalorimetry enabled real-time evaluation of antifungal activities against planktonic and biofilm Candida organisms. It can be used in the future to evaluate new antifungals and antifungal combinations and to study resistant strains. PMID:24566186

Comparative assessment of inoculum effects on the antimicrobial activity of amoxycillin-clavulanate and piperacillin-tazobactam with extended-spectrum beta-lactamase-producing and extended-spectrum beta-lactamase-non-producing Escherichia coli isolates.

PubMed

López-Cerero, L; Picón, E; Morillo, C; Hernández, J R; Docobo, F; Pachón, J; Rodríguez-Baño, J; Pascual, A

2010-02-01

A significant inoculum-size effect has been observed with piperacillin-tazobactam, and has been associated with beta-lactamase production in extended-spectrum beta-lactamase (ESBL) producers. This association has not been previously studied in the case of amoxycillin-clavulanate. Piperacillin-tazobactam and amoxycillin-clavulanate were compared, using high inocula of susceptible strains either harbouring ESBLs or not. Two non-ESBL-producing and 15 amoxycillin-clavulanate-susceptible and piperacillin-tazobactam-susceptible ESBL-producing Escherichia coli isolates, and their respective transconjugants, were tested in dilution susceptibility tests using standard and 100-fold higher inocula. Three ESBL-producing strains and E. coli ATCC 25922 were selected for time-kill studies using standard and high initial inocula. At high inocula, MICs of piperacillin increased >eight-fold for non-ESBL-producing strains, and MICs of piperacillin-tazobactam (8:1 ratio or with tazobactam fixed at 4 mg/L) increased>eight-fold for all ESBL-producing strains. However, amoxycillin MICs were not affected by a high inoculum with non-ESBL-producing strains, whereas the MICs of amoxycillin-clavulanate (2:1 and 4:1) increased

Rappaport-Vassiliadis medium for recovery of Salmonella spp. from low microbial load foods: collaborative study.

PubMed

Hammack, T S; Amaguaña, R M; Andrews, W H; Lerner, I

2001-01-01

Twenty-three laboratories participated in a collaborative study to compare the relative effectiveness of Rappaport-Vassiliadis (RV) medium incubated at 42 degrees C, selenite cystine (SC) broth (35 degrees C), and tetrathionate (TT) broth (35 and 43 degrees C) for recovery of Salmonella from the following foods with a low microbial load: dried egg yolk, dry active yeast, ground black pepper, guar gum, and instant nonfat dry milk. For dry active yeast, lauryl tryptose (LT) broth, incubated at 35 degrees C, was used instead of SC broth. All of the foods were artificially inoculated with single Salmonella serovars, that had been lyophilized before inoculation, at high and low target levels of 0.4 and 0.04 colony forming units/g food, respectively. For analysis of 870 test portions, representing all of the foods except yeast, 249 Salmonella-positive test portions were detected by RV medium, 265 by TT broth (43 degrees C), 268 by TT broth (35 degrees C), and 269 by SC broth (35 degrees C). For analysis of 225 test portions of yeast, 79 Salmonella-positive test portions were detected by RV medium, 79 by TT broth (43 degrees C), 84 by TT broth (35 degrees C), and 68 by LT broth (35 degrees C). RV medium was comparable to, or even more effective than, the other selective enrichments for recovery of Salmonella from all of the foods except guar gum. It is recommended that RV (42 degrees C) and TT (35 degrees C) be used with foods that have a low microbial load, except for guar gum for which SC (35 degrees C) and TT (35 degrees C) are recommended.

Supplementing chicken broth with monosodium glutamate reduces energy intake from high fat and sweet snacks in middle-aged healthy women.

PubMed

Imada, Toshifumi; Hao, Susan Shuzhen; Torii, Kunio; Kimura, Eiichiro

2014-08-01

Monosodium L-glutamate (MSG) and inosine monophosphate-5 (IMP) are flavor enhancers for umami taste. However, their effects on appetite and food intake are not well-researched. The objective of the current study was to test their additions in a broth preload on subsequent appetite ratings, energy intake and food choice. Eighty-six healthy middle-aged women with normal body weight received three preload conditions on 3 test days 1 week apart - a low-energy chicken flavor broth (200 ml) as the control preload, and broths with added MSG alone (0.5 g/100 ml, MSG broth) or in combination with IMP (0.05 g/100 ml) (MSG+ broth) served as the experimental conditions. Fifteen minutes after preload administration subjects were provided an ad libitum testing meal which consisted of 16 snacks varying in taste and fat content. MSG and MSG+ enhanced savory taste and broth properties of liking and pleasantness. In comparison with control, the MSG preload resulted in less consumption of total energy, as well as energy from sweet and high-fat snacks. Furthermore, MSG broth preload reduced added sugar intake. These findings were not observed after MSG+ preload. Appetite ratings were not different across the three preloads. Results suggest a potential role of MSG addition to a low-energy broth preload in subsequent energy intake and food choice. This trial was registered at clinicaltrials.gov as NCT01761045. Copyright © 2014 Elsevier Ltd. All rights reserved.

A new gas dilution method for measuring body volume.

PubMed Central

Nagao, N; Tamaki, K; Kuchiki, T; Nagao, M

1995-01-01

This study was designed to examine the validity of a new gas dilution method (GD) for measuring human body volume and to compare its accuracy with the results obtained by the underwater weighing method (UW). We measured the volume of plastic bottles and 16 subjects (including two females), aged 18-42 years with each method. For the bottles, the volume measured by hydrostatic weighing was correlated highly (r = 1.000) with that measured by the new gas dilution method. For the subjects, the body volume determined by the two methods was significantly correlated (r = 0.998). However, the subject's volume measured by the gas dilution method was significantly larger than that by underwater weighing method. There was significant correlation (r = 0.806) between GD volume-UW volume and the body mass index (BMI), so that UW volume could be predicted from GD volume and BMI. It can be concluded that the new gas dilution method offers promising possibilities for future research in the population who cannot submerge underwater. PMID:7551760

Resuscitation of acid-injured Salmonella in enrichment broth, in apple juice and on the surfaces of fresh-cut cucumber and apple.

PubMed

Liao, C-H; Fett, W F

2005-01-01

To investigate the resuscitation of acid-injured Salmonella enterica in selected enrichment broths, in apple juice and on cut surfaces of apple and cucumber slices. Following exposure to 2.4% acetic acid for 7 min, S. enterica (serovars Mbandaka, Chester and Newport) cells were used to inoculate enrichment broths, phosphate-buffered saline (PBS), apple juice and fruit slices. Injured Salmonella cells resuscitated and regained the ability to form colonies on selective agar (Xylose-Lysine-Tergitol 4) if they were incubated in lactose broth (LB), universal pre-enrichment broth (UPB) or buffered peptone water (BPW), but not in tetrathionate broth, PBS or apple juice. The resuscitation occurred at a significantly (P > 0.05) faster rate in UPB than in LB or BPW. The resuscitation also occurred on the surfaces of fresh-cut cucumber at 20 degrees C, but not at 4 degrees C. Acid-injured Salmonella cells resuscitated in nonselective enrichment broths at different rates, but not in selective enrichment broth, apple juice, PBS or on fresh-cut apple. Pre-enrichment of food samples in UPB prior to selective enrichment is recommended. Injured Salmonella cells have the ability to resuscitate on fresh-cut surfaces of cucumber when stored at abusive temperatures.

Detergents enhance EspB secretion from Escherichia coli strains harboring the locus for the enterocyte effacement (LEE) gene.

PubMed

Nakasone, Noboru; Toma, Claudia; Higa, Naomi; Koizumi, Yukiko; Ogura, Yasunori; Suzuki, Toshihiko

2011-02-01

The effects of detergents (cholic acid, deoxycholic acid, Triton X-100, and Nonidet P-40) on the secretion of EspB from the locus for enterocyte effacement (LEE) gene-positive Escherichia coli strains were examined. Clinical isolates of eight EPEC strains and seven STEC strains were used to detect EspB after they had been cultivated in Luria-Bertani (LB) broth containing one of the detergents. When the bacteria were cultured in LB broth supplemented with one of the detergents, the amount of EspB produced was increased by 2-32-fold depending on the detergent and the strain used. EspB was detected in all strains when they were cultured in LB broth containing all of the detergents. The results obtained in this study can be applied to immunological diagnostic methods for detecting EspB and also to the production of EspB for research purposes. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

In Vitro Comparison of Ertapenem, Meropenem, and Imipenem against Isolates of Rapidly Growing Mycobacteria and Nocardia by Use of Broth Microdilution and Etest

PubMed Central

Brown-Elliott, Barbara A.; Killingley, Jessica; Vasireddy, Sruthi; Bridge, Linda

2016-01-01

We compared the activities of the carbapenems ertapenem, meropenem, and imipenem against 180 isolates of rapidly growing mycobacteria (RGM) and 170 isolates of Nocardia using the Clinical and Laboratory Standards Institute (CLSI) guidelines. A subset of isolates was tested using the Etest. The rate of susceptibility to ertapenem and meropenem was limited and less than that to imipenem for the RGM. Analysis of major and minor discrepancies revealed that >90% of the isolates of Nocardia had higher MICs by the broth microdilution method than by Etest, in contrast to the lower broth microdilution MICs seen for >80% of the RGM. Imipenem remains the most active carbapenem against RGM, including Mycobacterium abscessus subsp. abscessus. For Nocardia, imipenem was significantly more active only against Nocardia farcinica. Although there may be utility in testing the activities of the newer carbapenems against Nocardia, their activities against the RGM should not be routinely tested. Testing by Etest is not recommended by the CLSI. PMID:27053677

Methods for increasing the production of ethanol from microbial fermentation

DOEpatents

Gaddy, James L [Fayetteville, AR; Arora, Dinesh K [Fayetteville, AR; Ko, Ching-Whan [Fayetteville, AR; Phillips, John Randall [Fayetteville, AR; Basu, Rahul [Bethlehem, PA; Wikstrom, Carl V [Fayetteville, AR; Clausen, Edgar C [Fayetteville, AR

2007-10-23

A stable continuous method for producing ethanol from the anaerobic bacterial fermentation of a gaseous substrate containing at least one reducing gas involves culturing a fermentation bioreactor anaerobic, acetogenic bacteria in a liquid nutrient medium; supplying the gaseous substrate to the bioreactor; and manipulating the bacteria in the bioreactor by reducing the redox potential, or increasing the NAD(P)H TO NAD(P) ratio, in the fermentation broth after the bacteria achieves a steady state and stable cell concentration in the bioreactor. The free acetic acid concentration in the bioreactor is maintained at less than 5 g/L free acid. This method allows ethanol to be produced in the fermentation broth in the bioreactor at a productivity greater than 10 g/L per day. Both ethanol and acetate are produced in a ratio of ethanol to acetate ranging from 1:1 to 20:1.

Flocked nylon swabs versus RODAC plates for detection of multidrug-resistant organisms on environmental surfaces in intensive care units.

PubMed

Okamoto, K; Rhee, Y; Schoeny, M; Lolans, K; Cheng, J; Reddy, S; Weinstein, R A; Hayden, M K; Popovich, K J

2018-01-01

To compare two culture methods [nylon fiber flocked swabs with broth enrichment versus RODAC ('replicate organism detection and counting') plates] for recovery of multidrug-resistant organisms, 780 environmental surfaces in 63 rooms of patients on contact precautions in four intensive care units at one hospital were examined. Among sites that had at least one positive culture, swab culture with broth enrichment detected the target organisms more frequently than RODAC plates (37.5% vs 26.0%, P = 0.06). There was moderate agreement between the two methods (κ = 0.44) with agreement better for small or flat surfaces compared to large or irregular surfaces. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

A rapid method for the determination of microbial susceptibility using the firefly luciferase assay for adenosine triphosphate (ATP)

NASA Technical Reports Server (NTRS)

Vellend, H.; Tuttle, S. A.; Barza, M.; Weinstein, L.; Picciolo, G. L.; Chappelle, E. W.

1975-01-01

Luciferase assay for adenosine triphosphate (ATP) was optimized for pure bacteria in broth in order to evaluate if changes in bacterial ATP content could be used as a rapid measure of antibiotic effect on microorganisms. Broth cultures of log phase bacteria were incubated at 310 K (37 C) for 2.5 hours at antimicrobial concentrations which resulted in the best discrimination between sensitive and resistant strains. Eighty-seven strains of 11 bacterial species were studied for their susceptibility to 12 commonly used antimicrobial agents: ampicillin, Penicillin G, nafcillin, carbenicillin, cephalothin, tetracycline, erythromycin, clindamycin, gentamicin, nitrofurantoin, colistin, and chloramplenicol. The major advantage of the ATP system over existing methods of rapid microbial susceptibility testing is that the assay can be made specific for bacterial ATP.

[Detection of Huperzine A and Huperzine B in fermentation broth of endophytic fungus Colletotrichum gloesporioides from Huperzia serrate by HPLC].

PubMed

Hu, Liqin; Kang, Xincong; Shen, Pengyuan; Chen, Tian; Zhang, Jiayin; Liu, Dongbo

2018-05-25

In this study, we established a rapid and efficient HPLC method to determine the accumulation of Huperzine A and Huperzine B in the fermentation broth of endophytic fungus Colletotrichum gloesporioides from Huperzia serrate. The chloroform extracts of fermentation broth were dissolved in methanol and filtered before injection for HPLC analysis. The analysis was performed on an Agilent Eclipse plus-C18 column (250 mm×4.6 mm, 5 μm) by isocratic elution. The mobile phase was 0.015 mol/L ammonium acetate-methanol (70:30, V/V), the flow rate was 1 mL/min and the detection wavelength was set at 308 nm. Huperzine A and Huperzine B could be well separated within 25 min. Good linearity of Huperzine A was found in the range of 1.50-48.00 μg/mL (r=0.999 5), and that of huperzine B was in 0.25-7.50 μg/mL (r=0.999 7). The average recoveries of Huperzine A and Huperzine B were 106.83% and 108.06%, respectively (RSD=3.34%, 3.60%). The results demonstrate that this method can detect the content of huperzine A and huperzine B in fermentation broth simply, rapidly, accurately and in good reproducibility. Under the optimized conditions, the accumulated content of huperzine A and huperzine B were measured from the sixth to the fifteenth day. Huperzine A and Huperzine B reached the highest (12.417 0 μg/mL and 4.660 3 μg/mL, respectively) at the fourteenth and eighth days. The analysis methodology could contribute to the future study of huperzine A and huperzine B biosynthesis in C. gloeosporioides, consequently facilitate the development of new drug resources.

Production of Viscous Dextran-Containing Whey-Sucrose Broths by Leuconostoc mesenteroides ATCC 14935.

PubMed

Schwartz, R D; Bodie, E A

1984-09-01

Viscous broths were produced by growing Leuconostoc mesenteroides on a medium containing whey supplemented with sucrose. When combined with similarly produced xanthan-containing broths, a synergistic increase in viscosity was observed.

Regression analysis and categorical agreement of fluconazole disk zone diameters and minimum inhibitory concentration by broth microdilution of clinical isolates of Candida.

PubMed

Aggarwal, P; Kashyap, B

2017-06-01

Rampant use of fluconazole in Candida infections has led to predominance of less susceptible non-albicans Candida over Candida albicans. The aim of the study was to determine if zone diameters around fluconazole disk can be used to estimate the minimum inhibitory concentration (MIC) for clinical isolates of Candida species and vice versa. Categorical agreement between the Clinical & Laboratory Standards Institute (CLSI) recommended disk diffusion and CLSI broth microdilution method was sought for. Antifungal susceptibility testing by disk diffusion and Broth microdilution was done as per CLSI document M44-S3 and CLSI document M27-S4 for Candida isolates respectively. Regression analysis correlating zone diameters to MIC value was done. Pearson's correlation coefficient was calculated to determine correlation between disk zone diameters and MICs. Candida albicans (33.3%) was clearly outnumbered by other non-albicans species predominantly Candida tropicalis (42.5%) and Candida glabrata (18.4%). Ten percent of the strains were resistant to fluconazole by disk diffusion and 13% by broth microdilution. MIC range for Candida albicans and Candida tropicalis ranged from≤0.25-64μg/ml while that of Candida glabrata ranged from≤0.25-128μg/ml. Categorical agreement between disk diffusion and broth microdilution was 86.8%. Pearson's coefficient of correlation was -0.5975 indicating moderate negative correlation between the two variables. Zone sizes can be used to estimate the MIC values, although with limited accuracy. There should be a constant effort to upgrade the guidelines in view of new clinical data, and laboratories should make an active effort to incorporate them. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Simple and rapid method for isolation and quantitation of polyhydroxyalkanoate by SDS-sonication treatment.

PubMed

Arikawa, Hisashi; Sato, Shunsuke; Fujiki, Tetsuya; Matsumoto, Keiji

2017-08-01

We developed a new method for isolation and quantitation of polyhydroxyalkanoate (PHA) from culture broth. In this method, the cells were sonicated in sodium dodecyl sulfate (SDS) solution and centrifuged to recover PHA. The recovered PHA was rinsed with deionized water and ethanol, and then weighed after drying. Hazardous chemicals such as chloroform, methanol, and sulfuric acid were not used, and no expensive analytical instruments were needed. We applied this method to Cupriavidus necator culture broths that included various amounts of poly(3-hydroxybutyrate) (PHB) or poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) from flasks and jar fermentors. The quantitation by this method was practical for use with a wide range of production amounts and PHA monomer compositions compared to the conventional whole-cell methanolysis method with gas chromatographic analysis, and besides, the recovered PHAs were adequately pure (≥96% purity). Therefore, this new method would be valuable not only for quantitation of PHA but also for preparation of samples to characterize their mechanical properties. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Rifaximin disc diffusion test for in vitro susceptibility testing of Clostridium difficile

PubMed Central

Huhulescu, Steliana; Sagel, Ulrich; Fiedler, Anita; Pecavar, Verena; Blaschitz, Marion; Wewalka, Guenther; Allerberger, Franz

2011-01-01

Rifaximin is a rifampicin derivative, poorly absorbed by the gastro-intestinal tract. We studied the in vitro susceptibility to rifamixin of 1082 Clostridium difficile isolates; among these,184 isolates from a strain collection were tested by an in-house rifaximin disc (40 µg) diffusion test, by an in-house rifaximin broth microdilution test, by rifampicin Etest and by rpoB gene sequencing. In the absence of respective CLSI or EUCAST MIC breakpoints for rifaximin and rifampicin against C. difficile we chose MIC ≥32 µg ml−1 as criterion for reduced in vitro susceptibility. To further validate the disc diffusion test 898 consecutive clinical isolates were analysed using the disc diffusion test, the Etest and rpoB gene sequence analysis for all resistant strains. Rifaximin broth microdilution tests of the 184 reference strains yielded rifaximin MICs ranging from 0.001 (n = 1) to ≥1024 µg ml−1 (n = 61); 62 isolates showed a reduced susceptibility (MIC ≥32 µg ml−1). All of these 62 strains showed rpoB gene mutations producing amino acid substitutions; the rifampicin- and rifaximin-susceptible strains showed either a wild-type sequence or silent amino acid substitutions (19 strains). For 11 arbitrarily chosen isolates with rifaximin MICs of >1024 µg ml−1, rifaximin end-point MICs were determined by broth dilution: 4096 µg ml−1 (n = 2), 8192 µg ml−1 (n = 6), 16 384 µg ml−1 (n = 2) and 32 678 µg ml−1 (n = 1). Rifampicin Etests on the 184 C. difficile reference strains yielded MICs ranging from ≤0.002 (n = 117) to ≥32 µg ml−1 (n = 59). Using a 38 mm inhibition zone as breakpoint for reduced susceptibility the use of rifaximin disc diffusion yielded 59 results correlating with those obtained by use of rifaximin broth microdilution in 98.4 % of the 184 strains tested. Rifampicin Etests performed on the 898 clinical isolates revealed that 67 isolates had MICs of ≥32 µg ml−1. There were no discordant results observed among these isolates with reduced susceptibility using an MIC of ≥32 µg ml−1 as breakpoint for reduced rifampicin susceptibility and a <38 mm inhibition zone as breakpoint for reduced rifaximin susceptibility. The prevalence of reduced susceptibility was 7.5 % for all isolates tested. However, for PCR ribotype 027 the prevalence of reduced susceptibility was 26 %. Susceptibility testing in the microbiology laboratory therefore could have an impact on the care and outcome of patients with infection. Our results show that rifaximin – despite its water-insolubility – may be a suitable candidate for disc diffusion testing. PMID:21292853

Agreement Assessment of Tigecycline Susceptibilities Determined by the Disk Diffusion and Broth Microdilution Methods among Commonly Encountered Resistant Bacterial Isolates: Results from the Tigecycline In Vitro Surveillance in Taiwan (TIST) Study, 2008 to 2010

PubMed Central

Liu, Jien-Wei; Ko, Wen-Chien; Huang, Cheng-Hua; Liao, Chun-Hsing; Lu, Chin-Te; Chuang, Yin-Ching; Tsao, Shih-Ming; Chen, Yao-Shen; Liu, Yung-Ching; Chen, Wei-Yu; Jang, Tsrang-Neng; Lin, Hsiu-Chen; Chen, Chih-Ming; Shi, Zhi-Yuan; Pan, Sung-Ching; Yang, Jia-Ling; Kung, Hsiang-Chi; Liu, Chun-Eng; Cheng, Yu-Jen; Chen, Yen-Hsu; Lu, Po-Liang; Sun, Wu; Wang, Lih-Shinn; Yu, Kwok-Woon; Chiang, Ping-Cherng; Lee, Ming-Hsun; Lee, Chun-Ming; Hsu, Gwo-Jong

2012-01-01

The Tigecycline In Vitro Surveillance in Taiwan (TIST) study, initiated in 2006, is a nationwide surveillance program designed to longitudinally monitor the in vitro activity of tigecycline against commonly encountered drug-resistant bacteria. This study compared the in vitro activity of tigecycline against 3,014 isolates of clinically important drug-resistant bacteria using the standard broth microdilution and disk diffusion methods. Species studied included methicillin-resistant Staphylococcus aureus (MRSA; n = 759), vancomycin-resistant Enterococcus faecium (VRE; n = 191), extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (n = 602), ESBL-producing Klebsiella pneumoniae (n = 736), and Acinetobacter baumannii (n = 726) that had been collected from patients treated between 2008 and 2010 at 20 hospitals in Taiwan. MICs and inhibition zone diameters were interpreted according to the currently recommended U.S. Food and Drug Administration (FDA) criteria and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. The MIC90 values of tigecycline against MRSA, VRE, ESBL-producing E. coli, ESBL-producing K. pneumoniae, and A. baumannii were 0.5, 0.125, 0.5, 2, and 8 μg/ml, respectively. The total error rates between the two methods using the FDA criteria were high: 38.4% for ESBL-producing K. pneumoniae and 33.8% for A. baumannii. Using the EUCAST criteria, the total error rate was also high (54.6%) for A. baumannii isolates. The total error rates between these two methods were <5% for MRSA, VRE, and ESBL-producing E. coli. For routine susceptibility testing of ESBL-producing K. pneumoniae and A. baumannii against tigecycline, the broth microdilution method should be used because of the poor correlation of results between these two methods. PMID:22155819

Method and apparatus for maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling

DOEpatents

Farthing, William Earl [Pinson, AL; Felix, Larry Gordon [Pelham, AL; Snyder, Todd Robert [Birmingham, AL

2008-02-12

An apparatus and method for diluting and cooling that is extracted from high temperature and/or high pressure industrial processes. Through a feedback process, a specialized, CFD-modeled dilution cooler is employed along with real-time estimations of the point at which condensation will occur within the dilution cooler to define a level of dilution and diluted gas temperature that results in a gas that can be conveyed to standard gas analyzers that contains no condensed hydrocarbon compounds or condensed moisture.

Method and apparatus maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling

DOEpatents

Farthing, William Earl; Felix, Larry Gordon; Snyder, Todd Robert

2009-12-15

An apparatus and method for diluting and cooling that is extracted from high temperature and/or high pressure industrial processes. Through a feedback process, a specialized, CFD-modeled dilution cooler is employed along with real-time estimations of the point at which condensation will occur within the dilution cooler to define a level of dilution and diluted gas temperature that results in a gas that can be conveyed to standard gas analyzers that contains no condensed hydrocarbon compounds or condensed moisture.

Production of Viscous Dextran-Containing Whey-Sucrose Broths by Leuconostoc mesenteroides ATCC 14935

PubMed Central

Schwartz, Robert D.; Bodie, Elizabeth A.

1984-01-01

Viscous broths were produced by growing Leuconostoc mesenteroides on a medium containing whey supplemented with sucrose. When combined with similarly produced xanthan-containing broths, a synergistic increase in viscosity was observed. PMID:16346633

Spontaneously Generating Life in Your Classroom? Pasteur, Spallanzani and Science Process.

ERIC Educational Resources Information Center

Byington, Scott

2001-01-01

Presents an experiment that tests for spontaneous generation, or abiogenesis. Observes microbial growth in nutrient broth under seven different flask environments. Includes instructions for the methods. (YDS)

Screening method for detection of immediate amino acid decarboxylases--producing bacteria implicated in food poisoning.

PubMed

Hussain, Husniza; Mohd Fuat, A R; Vimala, B; Ghazali, H M

2011-08-01

Assessment of amino acid decarboxylase activity can be conducted using tubed broth or plated agar. In this study, the test was carried out in microtitre plates containing lysine, ornithine, arginine, tyrosine, tryptophan, phenylalanine or histidine as biogenic amine precursors. Møller decarboxylase base broth (MDB) with or without 1% of a known amino acid were added to wells of a 96 well-microtitre plate. The wells were inoculated with Escherichia coli, Klebsiella pneumoniae, Acinetobacter anitratus or Staphylococcus aureus to the final concentration of 6.0 x 10(7) cfu/ml and incubated at 35ºC. The absorbance of the culture broth was read at 570 nm at 0, 1.0, 2.0, 3.0, 4.0, 5.5, 6.5 and 7.5 hour. Comparison of means of A'(570) between 0 hour and a specified incubation time was determined statistically. Positive decarboxylase activities were detected in the media inoculated with E. coli and K. pneumoniae in less than 6 hours. The current method is suitable for immediate producers of amino acid decarboxylase enzymes. It costs less as it uses less amino acid and it has the potential to be used for screening aliquots of food materials for amino acid decarboxylase activities.

Determination of Amino Acids in Cell Culture and Fermentation Broth Media Using Anion-Exchange Chromatography with Integrated Pulsed Amperometric Detection

PubMed Central

Hanko, Valoran P.; Heckenberg, Andrea; Rohrer, Jeffrey S.

2004-01-01

Anion-exchange chromatography with integrated pulsed amperometric detection (AE-IPAD) separates and directly detects amino acids, carbohydrates, alditols, and glycols in the same injection without pre- or post-column derivatization. These separations use a combination of NaOH and NaOH/sodium acetate eluents. We previously published the successful use of this technique, also known as AAA-Direct, to determine free amino acids in cell culture and fermentation broth media. We showed that retention of carbohydrates varies with eluent NaOH concentration differently than amino acids, and thus separations can be optimized by varying the initial NaOH concentration and its duration. Unfortunately, some amino acids eluting in the acetate gradient portion of the method were not completely resolved from system-related peaks and from unknown peaks in complex cell culture and fermentation media. In this article, we present changes in method that improve amino acid resolution and system ruggedness. The success of these changes and their compatibility with the separations previously designed for fermentation and cell culture are demonstrated with yeast extract-peptone-dextrose broth, M199, Dulbecco’s modified Eagle’s (with F-12), L-15 (Leibovitz), and McCoy’s 5A cell culture media. PMID:15585828

Deep freezing of Angora goat semen: effects of diluent composition and method and rate of dilution on survival of spermatozoa.

PubMed

Salamon, S; Ritar, A J

1982-01-01

Five factorial experiments were conducted to examine the effects of concentration of tris(hydroxymethyl)aminomethane (Tris), type and concentration of sugar in the diluent, rate and method of dilution on the survival of goat spermatozoa after freezing by the pellet method. Spermatozoa tolerated a relatively wide range in concentration of Tris, but the cell survival depended on the type of sugar included in the Tris diluent. Glucose and fructose were more suitable components than lactose or raffinose. Survival of spermatozoa after thawing was better for three- to fivefold prefreezing dilution. There was interaction between method of semen dilution (one-step, two-step), holding time at 5 degrees C, and glycerol concentration. The best result was obtained after one-step dilution at 30 degrees C (Tris 375 mM-glucose 41.625 mM-citric acid 124 mM), 1.5 h holding at 5 degrees C, and with 4% (v/v) glycerol concentration in the diluted semen.

Chemical constituents of the fermentation broth of the marine-derived fungus Penicillium roqueforti.

PubMed

Mioso, Roberto; Marante, Francisco Javier Toledo; Laguna, Irma Herrera Bravo de

2015-01-01

The filamentous fungus Penicillium roqueforti is a well-known multifunctional cell factory of high added-value biomolecules. The objective of this work was to carry out a detailed analysis of the metabolites present in the culture broth of a new marine-derived Penicillium roqueforti strain isolated in the Canary Islands, Spain. The fungal biomass production was carried out in liquid-state fermentation, and after 10-12 days of incubation at 22-25°C, the supernatant mycelia was separated by filtration, and the culture broth (12l) was stored in a refrigerator at 4°C for a subsequent liquid-liquid extraction with dichloromethane (3×), in accordance with the modified Kupchan method. The volatile and semi-volatile organic compounds were separated by chromatography and analyzed using GC-MS and NMR spectroscopy analyses. Several volatile organic compounds involved in the fatty acid pathway were identified: a terpenoid, a cyclic dipeptide, phthalates, and an alkyl adipate. In addition, three categories of non-volatile compounds (alkanes, fatty acids and 1-alkanols) were identified by spectroscopy. The results show that the fermented broth of this fungal strain has no mycotoxins under the culture conditions applied. It is hoped that this chemo-specific information will offer critical input for improving the biotechnological applications of this filamentous fungus. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Application of solid-phase microextraction with gas chromatography and mass spectrometry for the early detection of active moulds on historical woollen objects.

PubMed

Sawoszczuk, Tomasz; Syguła-Cholewińska, Justyna; Del Hoyo-Meléndez, Julio M

2017-02-01

The goal of this work was to determine the microbial volatile organic compounds emitted by moulds growing on wool in search of particular volatiles mentioned in the literature as indicators of active mould growth. The keratinolytically active fungi were inoculated on two types of media: (1) samples of wool placed on broths, and (2) on broths containing amino acids that are elements of the structure of keratin. All samples were prepared inside 20 mL vials (closed system). In the first case (1) the broths did not contain any sources of organic carbon, nitrogen, or sulfur, i.e. wool was the only nutrient for the moulds. A third type of sample was historical wool prepared in a Petri dish without a broth and inoculated with a keratinolytically active mould (open system). The microbial volatiles emitted by moulds were sampled with the headspace solid-phase microextraction method. Volatiles extracted on solid-phase microextraction fibers were analyzed in a gas chromatography with mass spectrometry system. Qualitative and quantitative analyses of chromatograms were carried out in search of indicators of metabolic activity. The results showed that there are three groups of volatiles that can be used for the detection of active forms of moulds on woollen objects. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Estimation method for serial dilution experiments.

PubMed

Ben-David, Avishai; Davidson, Charles E

2014-12-01

Titration of microorganisms in infectious or environmental samples is a corner stone of quantitative microbiology. A simple method is presented to estimate the microbial counts obtained with the serial dilution technique for microorganisms that can grow on bacteriological media and develop into a colony. The number (concentration) of viable microbial organisms is estimated from a single dilution plate (assay) without a need for replicate plates. Our method selects the best agar plate with which to estimate the microbial counts, and takes into account the colony size and plate area that both contribute to the likelihood of miscounting the number of colonies on a plate. The estimate of the optimal count given by our method can be used to narrow the search for the best (optimal) dilution plate and saves time. The required inputs are the plate size, the microbial colony size, and the serial dilution factors. The proposed approach shows relative accuracy well within ±0.1log10 from data produced by computer simulations. The method maintains this accuracy even in the presence of dilution errors of up to 10% (for both the aliquot and diluent volumes), microbial counts between 10(4) and 10(12) colony-forming units, dilution ratios from 2 to 100, and plate size to colony size ratios between 6.25 to 200. Published by Elsevier B.V.

Inactivation of Penicillins by Thiol Broth

PubMed Central

Murray, Patrick R.; Niles, Ann C.

1982-01-01

Thiol broth with sodium polyanetholesulfonate inactivated penicillin G, carbenicillin, nafcillin, oxacillin, and gentamicin, but had no effect on cephalothin, cefoxitin, clindamycin, chloramphenicol, erythromycin, and tetracycline. Only Thiol broth was capable of this inactivation, which was not influenced by the presence of blood. PMID:7153352

Videodensitometric Methods for Cardiac Output Measurements

NASA Astrophysics Data System (ADS)

Mischi, Massimo; Kalker, Ton; Korsten, Erik

2003-12-01

Cardiac output is often measured by indicator dilution techniques, usually based on dye or cold saline injections. Developments of more stable ultrasound contrast agents (UCA) are leading to new noninvasive indicator dilution methods. However, several problems concerning the interpretation of dilution curves as detected by ultrasound transducers have arisen. This paper presents a method for blood flow measurements based on UCA dilution. Dilution curves are determined by real-time densitometric analysis of the video output of an ultrasound scanner and are automatically fitted by the Local Density Random Walk model. A new fitting algorithm based on multiple linear regression is developed. Calibration, that is, the relation between videodensity and UCA concentration, is modelled by in vitro experimentation. The flow measurement system is validated by in vitro perfusion of SonoVue contrast agent. The results show an accurate dilution curve fit and flow estimation with determination coefficient larger than 0.95 and 0.99, respectively.

The importance of expressing antimicrobial agents on water basis in growth/no growth interface models: a case study for Zygosaccharomyces bailii.

PubMed

Dang, T D T; Vermeulen, A; Mertens, L; Geeraerd, A H; Van Impe, J F; Devlieghere, F

2011-01-31

In a previous study on Zygosaccharomyces bailii, three growth/no growth models have been developed, predicting growth probability of the yeast at different conditions typical for acidified foods (Dang, T.D.T., Mertens, L., Vermeulen, A., Geeraerd, A.H., Van Impe, J.F., Debevere, J., Devlieghere, F., 2010. Modeling the growth/no growth boundary of Z. bailii in acidic conditions: A contribution to the alternative method to preserve foods without using chemical preservatives. International Journal of Food Microbiology 137, 1-12). In these broth-based models, the variables were pH, water activity and acetic acid, with acetic acid concentration expressed in volume % on the total culture medium (i.e., broth). To continue the previous study, validation experiments were performed for 15 selected combinations of intrinsic factors to assess the performance of the model at 22°C (60days) in a real food product (ketchup). Although the majority of experimental results were consistent, some remarkable deviations between prediction and validation were observed, e.g., Z. bailii growth occurred in conditions where almost no growth had been predicted. A thorough investigation revealed that the difference between two ways of expressing acetic acid concentration (i.e., on broth basis and on water basis) is rather significant, particularly for media containing high amounts of dry matter. Consequently, the use of broth-based concentrations in the models was not appropriate. Three models with acetic acid concentration expressed on water basis were established and it was observed that predictions by these models well matched the validation results; therefore a "systematic error" in broth-based models was recognized. In practice, quantities of antimicrobial agents are often calculated based on the water content of food products. Hence, to assure reliable predictions and facilitate the application of models (developed from lab media with high dry matter contents), it is important to express antimicrobial agents' concentrations on a common basis-the water content. Reviews over other published growth/no growth models in literature are carried out and expressions of the stress factors' concentrations (on broth basis) found in these models confirm this finding. Copyright © 2010 Elsevier B.V. All rights reserved.

Improving culture media for the isolation of Clostridium difficile from compost.

PubMed

Dharmasena, Muthu; Jiang, Xiuping

2018-06-01

This study was to optimize the detection methods for Clostridium difficile from the animal manure-based composts. Both autoclaved and unautoclaved dairy composts were inoculated with a 12-h old suspension of a non-toxigenic C. difficile strain (ATCC 43593) and then plated on selected agar for vegetative cells and endospores. Six types of enrichment broths supplemented with taurocholate and l-cysteine were assessed for detecting a low level of artificially inoculated C. difficile (ca. 5 spores/g) from dairy composts. The efficacy of selected enrichment broths was further evaluated by isolating C. difficile from 29 commercial compost samples. Our results revealed that using heat-shock was more effective than using ethanol-shock for inducing endospore germination, and the highest endospore count (p < 0.05) was yielded at 60 °C for 25 min. C. difficile agar base, supplemented with 0.1% l-cysteine, 7% defibrinated horse blood, and cycloserine-cefoxitin (CDA-CYS-H-CC agar) was the best medium (p < 0.05) for recovering vegetative cells from compost. C. difficile endospore populations from both types of composts enumerated on both CDA-CYS-H-CC agar supplemented with 0.1% sodium taurocholate (CDA-CYS-H-CC-T agar) and brain heart infusion agar supplemented with 0.5% yeast extract, 0.1% l-cysteine, cycloserine-cefoxitin, and 0.1% sodium taurocholate (BHIA-YE-CYS-CC-T agar) media were not significantly different from each other (p > 0.05). Overall, enrichment of inoculated compost samples in broths containing moxalactam-norfloxacin (MN) produced significantly higher (p < 0.05) spore counts than in non-selective broths or broths supplemented with CC. Enrichment in BHIB-YE-CYS-MN-T broth followed by culturing on an agar containing 7% horse blood and 0.1% taurocholate provided a more sensitive and selective combination of media for detecting a low population of C. difficile from environmental samples with high background microflora. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ethnoveterinary study for antidermatophytic activity of Piper betle, Alpinia galanga and Allium ascalonicum extracts in vitro.

PubMed

Trakranrungsie, N; Chatchawanchonteera, A; Khunkitti, W

2008-02-01

Crude ethanolic extracts of Piper betle leaves (Piperaceae), Alpinia galanga rhizomes (Zingiberaceae) and Allium ascalonicum bulbs (Liliaceae) were tested against selected zoonotic dermatophytes (Microsporum canis, Microsporum gypseum and Trichophyton mentagrophyte) and the yeast-like Candida albicans. A broth dilution method was employed to determine the inhibitory effect of the extracts and compared to those of ketoconazole and griseofulvin. All extracts suppressed the growth of the fungi in a concentration-dependent manner. Among the extracts tested, P. betle exhibited more effective antifungal properties with average IC(50) values ranging from 110.44 to 119.00 microg/ml. Subsequently, 10% Piper betle (Pb) cream was formulated, subjected to physical and microbial limit test and evaluated for antifungal effect. The disc diffusion assay revealed comparable zones of inhibition between discs of Pb cream containing 80 microg P. betle extract and 80 microg ketoconazole against tested fungi at 96 h after incubation. Thereafter, the inhibitory effect of Pb cream markedly decreased and completely lost effectiveness by day 7. In summary, the results supported the traditional wisdom of herbal remedy use and suggested a potential value-addition to agricultural products. It was suggested that the Pb cream has potential therapeutic value for treatment of dermatophytosis. However, clinical testing as well as improving the Pb cream formulation with greater efficacy and duration of action would be of interest and awaits further investigation.

How Reliable Are ATP Bioluminescence Meters in Assessing Decontamination of Environmental Surfaces in Healthcare Settings?

PubMed Central

Omidbakhsh, Navid; Ahmadpour, Faraz; Kenny, Nicole

2014-01-01

Background Meters based on adenosine triphosphate (ATP) bioluminescence measurements in relative light units (RLU) are often used to rapidly assess the level of cleanliness of environmental surfaces in healthcare and other settings. Can such ATP measurements be adversely affected by factors such as soil and cleaner-disinfectant chemistry? Objective This study tested a number of leading ATP meters for their sensitivity, linearity of the measurements, correlation of the readings to the actual microbial contamination, and the potential disinfectant chemicals’ interference in their readings. Methods First, solutions of pure ATP in various concentrations were used to construct a standard curve and determine linearity and sensitivity. Serial dilutions of a broth culture of Staphylococcus aureus, as a representative nosocomial pathogen, were then used to determine if a given meter’s ATP readings correlated with the actual CFUs. Next, various types of disinfectant chemistries were tested for their potential to interfere with the standard ATP readings. Results All four ATP meters tested herein demonstrated acceptable linearity and repeatability in their readings. However, there were significant differences in their sensitivity to detect the levels of viable microorganisms on experimentally contaminated surfaces. Further, most disinfectant chemistries tested here quenched the ATP readings variably in different ATP meters evaluated. Conclusions Apart from their limited sensitivity in detecting low levels of microbial contamination, the ATP meters tested were also prone to interference by different disinfectant chemistries. PMID:24940751

Azole susceptibility of Malassezia pachydermatis and Malassezia furfur and tentative epidemiological cut-off values.

PubMed

Cafarchia, Claudia; Iatta, Roberta; Immediato, Davide; Puttilli, Maria Rita; Otranto, Domenico

2015-09-01

This study aims to determine the minimal inhibitory concentration (MIC) distribution and the epidemiological cut-off values (ECVs) of Malassezia pachydermatis and Malassezia furfur isolates for fluconazole (FLZ), itraconazole (ITZ), posaconazole (POS), and voriconazole (VOR). A total of 62 M. pachydermatis strains from dogs with dermatitis and 78 M. furfur strains from humans with bloodstream infections (BSI) were tested by a modified broth microdilution Clinical and Laboratory Standards Institute (CLSI) method. ITZ and POS displayed lower MICs than VOR and FLZ, regardless of the Malassezia species. The MIC data for azoles of M. pachydermatis were four two-fold dilutions lower than those of M. furfur. Based on the ECVs, about 94% of Malassezia strains might be categorized within susceptible population for all azoles, except for FLZ, and azole cross-resistance was detected in association with FLZ in M. pachydermatis but not in M. furfur.The study proposes, for the first time, tentative azole ECVs for M. pachydermatis and M. furfur for monitoring the emergence of isolates with decreased susceptibilities and shows that the azole MIC distribution varied according to the Malassezia species tested, thus suggesting the usefulness of determining the susceptibility profile for effective treatment of each species. © The Author 2015. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of extracts from Italian medicinal plants on planktonic growth, biofilm formation and adherence of methicillin-resistant Staphylococcus aureus

PubMed Central

Quave, Cassandra L.; Plano, Lisa R.W.; Pantuso, Traci; Bennett, Bradley C.

2008-01-01

One-third of botanical remedies from southern Italy are used to treat skin and soft tissue infection (SSTI). Staphylococcus aureus, a common cause of SSTI, has generated increasing concern due to drug resistance. Many plants possess antimicrobial agents and provide effective remedies for SSTI. Our aim was to investigate plants from different ethnobotanical usage groups for inhibition of growth and biofilms in methicillin-resistant S. aureus (MRSA). Three groups were assessed: plant remedies for SSTI, plant remedies not involving the skin, and plants with no ethnomedical application. We screened 168 extracts, representing 104 botanical species, for activity against MRSA (ATCC 33593). We employed broth dilution methods to determine the MIC after 18 hours growth using an optical density (OD600nm) reading. Anti-biofilm effects were assessed by growing biofilms for 40 hours, then fixing and staining with crystal violet. After washing, 10% Tween 80 was added and OD570nm readings were taken. Extracts from 10 plants exhibited an IC50 ≤32 μg/ml for biofilm inhibition: Lonicera alpigena, Castanea sativa, Juglans regia, Ballota nigra, Rosmarinus officinalis, Leopoldia comosa, Malva sylvestris, Cyclamen hederifolium, Rosa canina, and Rubus ulmifolius. Limited bacteriostatic activity was evident. The anti-biofilm activity of medicinal plants was significantly greater than plants without any ethnomedical applications. PMID:18556162

Tetracycline improved the efficiency of other antimicrobials against Gram-negative multidrug-resistant bacteria.

PubMed

Mawabo, Isabelle K; Noumedem, Jaurès A K; Kuiate, Jules R; Kuete, Victor

2015-01-01

Treatment of infectious diseases with antimicrobials constituted a great achievement in the history of medicine. Unfortunately, the emergence of resistant strains of bacteria to all classes of antimicrobials limited their efficacy. The present study was aimed at evaluating the effect of combinations of antibiotics on multi-drug resistant Gram-negative (MDRGN) bacteria. A liquid micro-broth dilution method was used to evaluate the antibacterial activity of 10 different classes of antimicrobials on 20 bacterial strains belonging to six different species. The antimicrobials were associated with phenylalanine β-naphthylamide (PAβN), an efflux pump inhibitor, and with other antimicrobials at their sub-inhibitory concentrations. The effectiveness of each combination was monitored using the minimal inhibitory concentration (MIC) and the fractional inhibitory concentration (FIC). Most of the antimicrobials tested showed low antibacterial activity with a MIC value of 128 mg/L on a majority of the bacterial strains, justifying their multidrug-resistant (MDR) profile. Synergistic effects were mostly observed (FIC≤0.5) when ampicillin (AMP), cloxacillin (CLX), erythromycin (ERY), chloramphenicol (CHL), kanamycin (KAN) and streptomycin (STR) were combined with tetracycline (TET) at the sub-inhibitory concentration of MIC/5 or MIC/10. The results of the present work suggest that the association of several antimicrobials with TET could improve the fight against MDRGN bacterial species. Copyright © 2014 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

Antibacterial activity of fresh pomegranate juice against clinical strains of Staphylococcus epidermidis

PubMed Central

Betanzos-Cabrera, Gabriel; Montes-Rubio, Perla Y.; Fabela-Illescas, Héctor E.; Belefant-Miller, Helen; Cancino-Diaz, Juan C.

2015-01-01

Background Polyphenols have received a great deal of attention due to their biological functions. Pomegranate (Punica granatum L.) is a polyphenol-rich fruit. In the past decade, studies testing the antimicrobial activity of pomegranates almost exclusively used solvent extracts instead of fresh pomegranate juice (FPJ). The use of FPJ instead of solvent extracts would reduce toxicity issues while increasing patient acceptance. We established a model to test FPJ as a natural antimicrobial agent. Objective To evaluate the antimicrobial activity of FPJ on clinical isolates of multidrug-resistant Staphylococcus epidermidis strains. Design Sixty strains of S. epidermidis isolated from ocular infections were grown in the presence of FPJ, and minimum inhibitory concentration (MIC) was determined by broth and agar dilution methods. Results FPJ at 20% had a MIC equal to 100% (MIC100%) on all 60 strains tested. This inhibition of FPJ was confirmed by the growth kinetics of a multidrug-resistant strain exposed to different concentrations of FPJ. Additionally, the antimicrobial activity of FPJ was compared against commercial beverages containing pomegranate: Ocean Spray® had a MIC100% at 20%, followed by Del Valle® with a MIC15% at 20% concentration only. The beverages Jumex® and Sonrisa® did not have any antimicrobial activity. FPJ had the highest polyphenol content and antioxidant capacity. Conclusions Overall, FPJ had antimicrobial activity, which might be attributed to its high polyphenol content and antioxidant capacity. PMID:25999265

Methyl Gallate from Galla rhois Successfully Controls Clinical Isolates of Salmonella Infection in Both In Vitro and In Vivo Systems

PubMed Central

Choi, Jang-Gi; Mun, Su-Hyun; Chahar, Harendra S.; Bharaj, Preeti; Kang, Ok-Hwa; Kim, Se-Gun; Shin, Dong-Won; Kwon, Dong-Yeul

2014-01-01

Galla rhois is a commonly used traditional medicine for the treatment of pathogenic bacteria in Korea as well as in other parts of Asia. Methyl gallate (MG), a major component of Galla Rhois, exhibits strong antibacterial activity, but its mechanism of action against Salmonella spp. is unclear. In the present study, we investigated the antibacterial actions of MG against Salmonella. The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of MG against Salmonella strains ranged from 3.9 to 125 µg/ml. In vitro bacterial viability test indicated that MG significantly decreased the viability of Salmonella over 40% when combined with ATPase inhibitors. The time-kill curves showed that a combined MG and ATPase inhibitors (DCCD and NaN3) treatment reduced the bacterial counts dramatically after 24 h. Oral administration of MG showed a strong anti-bacterial activity against WS-5 infected BALB/c mice. In contrast to the untreated Salmonella infected control animals, MG treated groups showed no clinical symptoms of the disease, such as lethargy and liver damage. It was observed that MG treatment significantly increased the survival of animals from Salmonella infection, while in untreated groups all animal succumbed to disease by the sixth day post infection. Thus, the present study demonstrates the therapeutic ability of MG against Salmonella infections. PMID:25048362

Synthesis, spectroscopic characterization, antimicrobial evaluation and molecular docking study of novel triazine-quinazolinone based hybrids

NASA Astrophysics Data System (ADS)

Dinari, Mohammad; Gharahi, Fateme; Asadi, Parvin

2018-03-01

A new series of 1,3,5-triazine incorporating aromatic quinazolinone moieties as a potential antimicrobial agents is reported. The first chlorine group of the cyanuric chloride (1) was replaced by aniline and the second one was replaced by various aromatic amines. The prepared monochlorotriazine was allowed to react with hydrazine and subsequently it was reacted with 2-methyl-4H-benzo[1,3]oxazin-4-one to obtain novel triazine-quinazolinone based hybrids (9a-f). The chemical structure and purity of the hybrid compounds were evaluated by different techniques such as thin layer chromatography, melting point, Fourier-transform infrared (FTIR), 1H and 13C NMR spectra and elemental analysis. Antimicrobial activity of the hybrid compounds were study by three Gram-negative bacteria (Salmonella entritidis, Escherichia coli, Pseudomonas aeruginosa) and three Gram-positive bacteria (Staphylococcus aureus, Listeria monocitogenes, Bacillus subtilis) as well as Candida albicansas a yeast-like fungus using the serial broth dilution method. Among them, compound 9d with benzenesulfonamide group showed higher antimicrobial activity with a minimum inhibitory concentration (MIC) value of 16 μg/mL. Furthermore, compounds 5d, 9a and 9b showed good activity against several tested strains. In addition, docking simulation was perform to position best antibacterial compounds in to the S. aureus dihydrofolate reductase (DHFR) active site to determine the probable binding conformations.

Potentiation activity of multiple antibacterial agents by Salvianolate from the Chinese medicine Danshen against methicillin-resistant Staphylococcus aureus (MRSA).

PubMed

Liu, Qing-Qing; Han, Jun; Zuo, Guo-Ying; Wang, Gen-Chun; Tang, Hua-Shu

2016-05-01

Salvianolate (SAL) is a prescribed medicine from the Chinese herb Danshen (Salvia miltiorrhiza Bunge). It has been widely used in treatment of coronary and other diseases with significant effects. The in vitro antimicrobial activities of SAL against infectious pathogens were assayed and its combined effects on 10 clinical isolates of SCCmec III type methicillin-resistant Staphylococcus aureus (MRSA) with ten antibiotics were evaluated. Susceptibility to each agent alone was tested using a broth microdilution method, and the chequerboard and time-kill experiments were used for the combined activities. The results showed MIC was 128-256 mg/L for SAL used alone against MRSA. Significant synergies were observed for SAL/Ampicillin (Fosfomycin, Erythromycin, Piperacillin-tazobactam or Clindamycin) combination against over half of the isolates, with their MICs reduced by times of dilution (TOD) to 4-32 (FICIs 0.375-0.5), respectively. SAL/AMP combination showed the best combined effect of synergy on bacteriostatic and bactericidal activities, while SAL/AMK combination reversed the resistance of MRSA to AMK. The results demonstrated that SAL enhanced widely the in vitro anti-MRSA efficacy of the ten antibacterial agents, which had potential for combinatory therapy of patients infected with MRSA and warrants further investigations. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Individual cell lag time distributions of Cronobacter (Enterobacter sakazakii) and impact of pooling samples on its detection in powdered infant formula.

PubMed

Miled, Rabeb Bennour; Guillier, Laurent; Neves, Sandra; Augustin, Jean-Christophe; Colin, Pierre; Besse, Nathalie Gnanou

2011-06-01

Cells of six strains of Cronobacter were subjected to dry stress and stored for 2.5 months at ambient temperature. The individual cell lag time distributions of recovered cells were characterized at 25 °C and 37 °C in non-selective broth. The individual cell lag times were deduced from the times taken by cultures from individual cells to reach an optical density threshold. In parallel, growth curves for each strain at high contamination levels were determined in the same growth conditions. In general, the extreme value type II distribution with a shape parameter fixed to 5 (EVIIb) was the most effective at describing the 12 observed distributions of individual cell lag times. Recently, a model for characterizing individual cell lag time distribution from population growth parameters was developed for other food-borne pathogenic bacteria such as Listeria monocytogenes. We confirmed this model's applicability to Cronobacter by comparing the mean and the standard deviation of individual cell lag times to populational lag times observed with high initial concentration experiments. We also validated the model in realistic conditions by studying growth in powdered infant formula decimally diluted in Buffered Peptone Water, which represents the first enrichment step of the standard detection method for Cronobacter. Individual lag times and the pooling of samples significantly affect detection performances. Copyright © 2010 Elsevier Ltd. All rights reserved.

Incidence of temonera, sulphuhydryl variables and cefotaximase genes associated with β-lactamase producing escherichia coli in clinical isolates

PubMed Central

Isaiah, Ibeh Nnana; Nche, Bikwe Thomas; Nwagu, Ibeh Georgina; Nwagu, Ibeh Isaiah

2011-01-01

Background: the occurrence of the different types of Extended spectrum beta Lactamase producing Escherichia coli with the, Sulphurhydryl variable, Temonera and the Cefotaximase have been on the rise Aim: The study was to determine the prevalence of extended spectrum beta lactamase gene resistance across the clinical isolates of hospitalized patients. Materials and Method: Three hundred and fifty isolates of Escherichia coli were received from different clinical specimens. The susceptibility profile of the isolates against 10 different antibiotics was examined, the MICs (Minimum Inhibitory Concentration) for ceftazidime were also determined using micro-broth dilution assay. Isolates showing MIC ≥ 6 μg/ml for ceftazidime were screened for ESBL (PCT)phenotypic confirmatory test and subjected to PCR (polymerase chain reaction) to further. Results: By disk diffusion test, there was resistance to ceftazidime and cefotaxime were 180(51.4%) and 120 (34.2%) respectively. However, all strains were susceptible to imipenem. 250 isolates showed MICs≥ 6 μg/ml for ceftazidime of which 180 (72%) were positive for extended spectrum beta lactamase. The prevalence of Sulphurhydryl variable, Temonera and the Cefotaximase among these isolates were 17.1%, 6.6% and 17%, respectively. Conclusion: For the identification of extended spectrum beta lactamase producing isolates it is recommended that clinical laboratories adopt simple test based on Cinical laboratory standard institute recommendation for confirming extended spectrum beta lactamase production in enterobacteriacea species. PMID:22363078

Methyl gallate from Galla rhois successfully controls clinical isolates of Salmonella infection in both in vitro and in vivo systems.

PubMed

Choi, Jang-Gi; Mun, Su-Hyun; Chahar, Harendra S; Bharaj, Preeti; Kang, Ok-Hwa; Kim, Se-Gun; Shin, Dong-Won; Kwon, Dong-Yeul

2014-01-01

Galla rhois is a commonly used traditional medicine for the treatment of pathogenic bacteria in Korea as well as in other parts of Asia. Methyl gallate (MG), a major component of Galla Rhois, exhibits strong antibacterial activity, but its mechanism of action against Salmonella spp. is unclear. In the present study, we investigated the antibacterial actions of MG against Salmonella. The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of MG against Salmonella strains ranged from 3.9 to 125 µg/ml. In vitro bacterial viability test indicated that MG significantly decreased the viability of Salmonella over 40% when combined with ATPase inhibitors. The time-kill curves showed that a combined MG and ATPase inhibitors (DCCD and NaN3) treatment reduced the bacterial counts dramatically after 24 h. Oral administration of MG showed a strong anti-bacterial activity against WS-5 infected BALB/c mice. In contrast to the untreated Salmonella infected control animals, MG treated groups showed no clinical symptoms of the disease, such as lethargy and liver damage. It was observed that MG treatment significantly increased the survival of animals from Salmonella infection, while in untreated groups all animal succumbed to disease by the sixth day post infection. Thus, the present study demonstrates the therapeutic ability of MG against Salmonella infections.

Endophthalmitis caused by Fusarium: An emerging problem in patients with corneal trauma. A case series.

PubMed

Barrios Andrés, José Luis; López-Soria, Leyre Mónica; Alastruey Izquierdo, Ana; Echevarría Ecenarro, Jaime; Feijoó Lera, Raquel; Garrido Fierro, Jesus; Cabrerizo Nuñez, Francisco Javier; Canut Blasco, Andrés

Although fortunately very rare in countries with a temperate climate, certain factors, such as clinical or pharmacological immunosuppression, may cause Fusarium-related fungal infections to become an emerging problem. Moreover, Fusarium is one of the most important etiological agents in exogenous endophthalmitis, which is often favored by the disruption of the epithelial barriers. The aim of this series of clinical cases is to identify characteristic clinical findings that may allow an early diagnosis and more efficient management of this ophthalmologic emergency. Three cases of endophthalmitis due to Fusarium solani and Fusarium oxysporum, diagnosed in 2009, 2010, and 2014 in patients from two different health regions belonging to the same health system and separated by around 43 miles, are presented. The Fusarium isolates were initially identified microscopically and the species subsequently confirmed by sequencing the elongation factor alpha (EFα) and internal transcribed spacers (ITS). Susceptibility to antifungal agents was determined using the EUCAST broth dilution method. Evolution was poor as two of the three patients progressed to phthisis bulbi despite surgical measures and broad-spectrum antifungal antibiotic therapy. It is essential to rapidly instigate multidisciplinary measures to combat suspected endophthalmitis due to Fusarium given the poor prognosis of this type of infection. Copyright © 2018 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

Growth inhibition of Cronobacter spp. strains in reconstituted powdered infant formula acidified with organic acids supported by natural stomach acidity.

PubMed

Zhu, S; Schnell, S; Fischer, M

2013-09-01

Cronobacter is associated with outbreaks of rare, but life-threatening cases of meningitis, necrotizing enterocolitis, and sepsis in newborns. This study was conducted to determine the effect of organic acids on growth of Cronobacter in laboratory medium and reconstituted powdered infant formula (PIF) as well as the bacteriostatic effect of slightly acidified infant formula when combined with neonatal gastric acidity. Inhibitory effect of seven organic acids on four acid sensitive Cronobacter strains was determined in laboratory medium with broth dilution method at pH 5.0, 5.5 and 6.0. Acetic, butyric and propionic acids were most inhibitive against Cronobacter in the laboratory medium. The killing effect of these three acids was partially buffered in reconstituted PIF. Under neonatal gastric acid condition of pH 5.0, the slightly acidified formula which did not exert inhibition effect solely reduced significantly the Cronobacter populations. A synergistic effect of formula moderately acidified with organic acid combined with the physiological infant gastric acid was visible in preventing the rapid growth of Cronobacter in neonatal stomach. The study contributed to a better understanding of the inhibitory effect of organic acids on Cronobacter growth in different matrixes and provided new ideas in terms of controlling bacteria colonization and translocation by acidified formula. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluation of the antibacterial activity of the Althaea officinalis L. leaf extract and its wound healing potency in the rat model of excision wound creation.

PubMed

Rezaei, Maryam; Dadgar, Zeynab; Noori-Zadeh, Ali; Mesbah-Namin, Seyed Alireza; Pakzad, Iraj; Davodian, Elham

2015-01-01

Wound is defined simply as the disruption of the biochemical, cellular, and anatomic continuity of a tissue. Plants and their extracts known as phytomedicine have immense potential for the management and treatment of wounds. Due to the undesirable side effects, in the control and treatment of the wound infections, it is recommended to use natural materials such as phytochemicals instead of chemically synthesized drugs. Thus, the aim of this research was to study the anti-microbial and wound healing potential of Althaea officinalis L. hydroalchoholic extract in comparison with ciprofloxacin, gentamicin, and penicillin antibiotics on clinical strains as well as pathogenic bacteria such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes under in vitro conditions using micro broth dilution and disc diffusion methods. Moreover, MIC and MBC of its hydroalchoholic extract was also evaluated. The results showed that although Althaea officinalis L. extract was not effective on gram-negative bacteria but it was efficacious on gram-positive bacteria. The extract was also tested in the form of topical administration on excision wound model in rats. In the extract-treated wounds, the wound healing percent was significantly increased in comparison with controls. Based on this research, herbal extract of officinalis L. can be a great candidate for the treatment of gram-positive infections and merits further studies.

Evaluation of the Antibacterial and Antifungal Properties of Phragmanthera capitata (Sprengel) Balle (Loranthaceae), a Mistletoe Growing on Rubber Tree, Using the Dilution Techniques

PubMed Central

2017-01-01

The alarming increase in multidrug resistance of pathogenic microorganisms to conventional drugs in recent years has prompted the search for new leads in alternative remedies in natural products. Hence, this study was aimed at evaluating the antimicrobial properties of Phragmanthera capitata, a parasitic mistletoe growing on rubber trees. The in vitro antimicrobial activities of the acetone, methanol, ethanol, and aqueous extracts were investigated using five gram-negative and five gram-positive bacteria and four fungi. A 96-well resazurin broth and agar dilution techniques were used for the determination of the Minimum Inhibitory and Bactericidal Concentrations. The antibacterial activity of the organic extracts had comparative effects on all the bacteria with a MIC of 1.25 to 5 mg/mL and MBC of 2.5 to 10 mg/mL. However, the acetone extract showed higher bactericidal effect while the aqueous extract was not active. The organic solvent extracts also showed antifungal activities on two of the fungi with a MIC of 1.25 mg/mL to 10 mg/mL. However, the aqueous extract had the highest activity inhibiting all the fungi with a MIC of ≤0.3125 to 1.25 mg/mL. The study supports the ethnomedicinal claims of P. capitata as a remedy for the diseases/infections caused by these organisms. PMID:28642934

Intrinsic Resistance of Burkholderia cepacia Complex to Benzalkonium Chloride

PubMed Central

Ahn, Youngbeom; Kim, Jeong Myeong; Kweon, Ohgew; Kim, Seong-Jae; Jones, Richard C.; Woodling, Kellie; Gamboa da Costa, Gonçalo; LiPuma, John J.; Hussong, David; Marasa, Bernard S.

2016-01-01

ABSTRACT Pharmaceutical products that are contaminated with Burkholderia cepacia complex (BCC) bacteria may pose serious consequences to vulnerable patients. Benzyldimethylalkylammonium chloride (BZK) cationic surfactants are extensively used in medical applications and have been implicated in the coselection of antimicrobial resistance. The ability of BCC to degrade BZK, tetradecyldimethylbenzylammonium chloride (C14BDMA-Cl), dodecyldimethylbenzylammonium chloride (C12BDMA-Cl), decyldimethylbenzylammonium chloride (C10BDMA-Cl), hexyldimethylbenzylammonium chloride, and benzyltrimethylammonium chloride was determined by incubation in 1/10-diluted tryptic soy broth (TSB) to determine if BCC bacteria have the ability to survive and inactivate these disinfectants. With BZK, C14BDMA-Cl, and C12BDMA-Cl, inhibition of the growth of 20 BCC strains was observed in disinfectant solutions that ranged from 64 to 256 µg/ml. The efflux pump inhibitor carbonyl cyanide m-chlorophenylhydrazone increased the sensitivity of bacteria to 64 µg/ml BZK. The 20 BCC strains grew well in 1/10-diluted TSB medium with BZK, C12BDMA-Cl, and C10BDMA-Cl; they absorbed and degraded the compounds in 7 days. Formation of benzyldimethylamine and benzylmethylamine as the initial metabolites suggested that the cleavage of the C alkyl-N bond occurred as the first step of BZK degradation by BCC bacteria. Proteomic data confirmed the observed efflux activity and metabolic inactivation via biodegradation in terms of BZK resistance of BCC bacteria, which suggests that the two main resistance mechanisms are intrinsic and widespread. PMID:27879334

Effect of essential oil concentration on the pH of nutrient and Iso-sensitest broth.

PubMed

Hood, J R; Cavanagh, H M A; Wilkinson, J M

2004-11-01

The role of pH on the antimicrobial activity of essential oils has not been well studied. The effect of four essential oils: Backhousia citriodora, Melaleuca alternifolia, Lavandula angustifolia and Santalum spicatum (0.1% to 10%) on the pH of two commonly used media, nutrient broth and Iso-sensitest broth, was therefore undertaken. Small (less than 0.5 pH units) but statistically significant differences between the pH of the two media followed the addition of M. alternifolia, L. angustifolia and S. spicatum essential oil. In general the effect on pH was greatest at higher concentrations and the fall in pH was greatest in the nutrient broth. The addition of B. citriodora essential oil to nutrient broth resulted in a fall in pH from 7.29 +/- 0.02 (no oil) to 5.2 +/- 0.03 (10% oil). This effect was not observed in the Iso-sensitest broth. Copyright 2004 John Wiley & Sons, Ltd.

Nitrogen fixation system of tungsten-resistant mutants of Azotobacter vinelandii.

PubMed Central

Riddle, G D; Simonson, J G; Hales, B J; Braymer, H D

1982-01-01

Mutants of Azotobacter vinelandii ATCC 12837 were isolated which could fix N2 in the presence of high tungsten concentrations. The most studied of these mutants (WD2) grew well in N-free modified Burk broth containing 10 mM W, whereas the wild type would not grow in this medium. WD2 would also grow in Burk N-free broth at about the same rate as the wild type. WD2 in broth containing W exhibited 22% of the whole cell acetylene reduction activity of the wild type in broth containing Mo and showed a lowered affinity for acetylene. Two-dimensional gel electrophoresis experiments showed that N2-fixing cells of WD2 from broth containing W or Mo did not produce significant amounts of component I of native nitrogenase protein. Electron spin resonance spectra of whole cells and cell-free extracts of WD2 from broth containing W lacked any trace of the g = 3.6 resonance associated with FeMoCo. Images PMID:6956567

Semiquantitative determination of mesophilic, aerobic microorganisms in cocoa products using the Soleris NF-TVC method.

PubMed

Montei, Carolyn; McDougal, Susan; Mozola, Mark; Rice, Jennifer

2014-01-01

The Soleris Non-fermenting Total Viable Count method was previously validated for a wide variety of food products, including cocoa powder. A matrix extension study was conducted to validate the method for use with cocoa butter and cocoa liquor. Test samples included naturally contaminated cocoa liquor and cocoa butter inoculated with natural microbial flora derived from cocoa liquor. A probability of detection statistical model was used to compare Soleris results at multiple test thresholds (dilutions) with aerobic plate counts determined using the AOAC Official Method 966.23 dilution plating method. Results of the two methods were not statistically different at any dilution level in any of the three trials conducted. The Soleris method offers the advantage of results within 24 h, compared to the 48 h required by standard dilution plating methods.

Optimization of single plate-serial dilution spotting (SP-SDS) with sample anchoring as an assured method for bacterial and yeast cfu enumeration and single colony isolation from diverse samples.

PubMed

Thomas, Pious; Sekhar, Aparna C; Upreti, Reshmi; Mujawar, Mohammad M; Pasha, Sadiq S

2015-12-01

We propose a simple technique for bacterial and yeast cfu estimations from diverse samples with no prior idea of viable counts, designated as single plate-serial dilution spotting (SP-SDS) with the prime recommendation of sample anchoring (10 0 stocks). For pure cultures, serial dilutions were prepared from 0.1 OD (10 0 ) stock and 20 μl aliquots of six dilutions (10 1 -10 6 ) were applied as 10-15 micro-drops in six sectors over agar-gelled medium in 9-cm plates. For liquid samples 10 0 -10 5 dilutions, and for colloidal suspensions and solid samples (10% w/v), 10 1 -10 6 dilutions were used. Following incubation, at least one dilution level yielded 6-60 cfu per sector comparable to the standard method involving 100 μl samples. Tested on diverse bacteria, composite samples and Saccharomyces cerevisiae , SP-SDS offered wider applicability over alternative methods like drop-plating and track-dilution for cfu estimation, single colony isolation and culture purity testing, particularly suiting low resource settings.

Short communication: an in vitro assessment of the antibacterial activity of plant-derived oils.

PubMed

Mullen, K A E; Lee, A R; Lyman, R L; Mason, S E; Washburn, S P; Anderson, K L

2014-09-01

Nonantibiotic treatments for mastitis are needed in organic dairy herds. Plant-derived oils may be useful but efficacy and potential mechanisms of action of such oils in mastitis therapy have not been well documented. The objective of the current study was to evaluate the antibacterial activity of the plant-derived oil components of Phyto-Mast (Bovinity Health LLC, Narvon, PA), an herbal intramammary product, against 3 mastitis-causing pathogens: Staphylococcus aureus, Staphylococcus chromogenes, and Streptococcus uberis. Plant-derived oils evaluated were Thymus vulgaris (thyme), Gaultheria procumbens (wintergreen), Glycyrrhiza uralensis (Chinese licorice), Angelica sinensis, and Angelica dahurica. Broth dilution testing according to standard protocol was performed using ultrapasteurized whole milk instead of broth. Controls included milk only (negative control), milk + bacteria (positive control), and milk + bacteria + penicillin-streptomycin (antibiotic control, at 1 and 5% concentrations). Essential oil of thyme was tested by itself and not in combination with other oils because of its known antibacterial activity. The other plant-derived oils were tested alone and in combination for a total of 15 treatments, each replicated 3 times and tested at 0.5, 1, 2, and 4% to simulate concentrations potentially achievable in the milk within the pre-dry-off udder quarter. Thyme oil at concentrations ≥2% completely inhibited bacterial growth in all replications. Other plant-derived oils tested alone or in various combinations were not consistently antibacterial and did not show typical dose-response effects. Only thyme essential oil had consistent antibacterial activity against the 3 mastitis-causing organisms tested in vitro. Further evaluation of physiological effects of thyme oil in various preparations on mammary tissue is recommended to determine potential suitability for mastitis therapy. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

In Vitro Inhibition of Klebsiella pneumoniae by Lactobacillus delbrueckii Subsp. delbrueckii LDD01 (DSM 22106): An Innovative Strategy to Possibly Counteract Such Infections in Humans?

PubMed

Mogna, Luca; Deidda, Francesca; Nicola, Stefania; Amoruso, Angela; Del Piano, Mario; Mogna, Giovanni

To determine the in vitro antimicrobial activity of selected Lactobacillus strains isolated from the feces of healthy humans against Klebsiella pneumoniae. Klebsiella is ubiquitous in nature and may colonize the skin, the pharynx, or the gastrointestinal tract of humans. Despite the widespread use of antibiotic molecules with a broad spectrum in hospitalized patients, an increased overall load of klebsiellae as well as the subsequent development of multidrug-resistant strains able to synthesize extended-spectrum beta-lactamase have been registered. These strains are particularly virulent, express capsular-type K55, and have a considerable ability to propagate. The 4 strains Lactobacillus paracasei LPC01 (CNCM I-1390), Lactobacillus rhamnosus LR04 (DSM 16605), Bifidobacterium longum B2274 (DSM 24707), and Lactobacillus delbrueckii subsp. delbrueckii LDD01 (DSM 22106) were tested. The analysis was performed using both a disc-diffusion assay and the broth-dilution procedure, also including an evaluation of the supernatants obtained from a fresh broth culture of each bacterium. L. delbrueckii subsp. delbrueckii LDD01 demonstrated the best inhibitory results among all the tested strains. The antibacterial activity of the supernatant was retained even after treatment with α-amylase and neutralization with NaOH 1N, thus suggesting the protein structure of the inhibitory molecule. In contrast, it was completely lost after treatment with proteinase K. Overall results suggest that the inhibitory effect of L. delbrueckii subsp. delbrueckii LDD01 should be attributed to the production of a bacteriocin. This strain may be prospectively useful for strengthening probiotic formulations and possibly counteract infections by K. pneumoniae in humans.

Pseudomonas aeruginosa cells adapted to benzalkonium chloride show resistance to other membrane-active agents but not to clinically relevant antibiotics.

PubMed

Loughlin, M F; Jones, M V; Lambert, P A

2002-04-01

Our objective was to determine whether strains of Pseudomonas aeruginosa can adapt to growth in increasing concentrations of the disinfectant benzalkonium chloride (BKC), and whether co-resistance to clinically relevant antimicrobial agents occurs. Attempts were made to determine what phenotypic alterations accompanied resistance and whether these explained the mechanism of resistance. Strains were serially passaged in increasing concentrations of BKC in static nutrient broth cultures. Serotyping and genotyping were used to determine purity of the cultures. Two strains were examined for cross-resistance to other disinfectants and antibiotics by broth dilution MIC determination. Alterations in outer membrane proteins and lipopolysaccharide (LPS) expressed were examined by SDS-PAGE. Cell surface hydrophobicity and charge, uptake of disinfectant and proportion of specific fatty acid content of outer and cytoplasmic membranes were determined. Two P. aeruginosa strains showed a stable increase in resistance to BKC. Co-resistance to other quaternary ammonium compounds was observed in both strains; chloramphenicol and polymyxin B resistance were observed in one and a reduction in resistance to tobramycin observed in the other. However, no increased resistance to other biocides (chlorhexidine, triclosan, thymol) or antibiotics (ceftazidime, imipenem, ciprofloxacin, tobramycin) was detected. Characteristics accompanying resistance included alterations in outer membrane proteins, uptake of BKC, cell surface charge and hydrophobicity, and fatty acid content of the cytoplasmic membrane, although no evidence was found for alterations in LPS. Each of the two strains had different alterations in phenotype, indicating that such adaptation is unique to each strain of P. aeruginosa and does not result from a single mechanism shared by the whole species.

Biosurfactant production from marine hydrocarbon-degrading consortia and pure bacterial strains using crude oil as carbon source

PubMed Central

Antoniou, Eleftheria; Fodelianakis, Stilianos; Korkakaki, Emmanouela; Kalogerakis, Nicolas

2015-01-01

Biosurfactants (BSs) are “green” amphiphilic molecules produced by microorganisms during biodegradation, increasing the bioavailability of organic pollutants. In this work, the BS production yield of marine hydrocarbon degraders isolated from Elefsina bay in Eastern Mediterranean Sea has been investigated. The drop collapse test was used as a preliminary screening test to confirm BS producing strains or mixed consortia. The community structure of the best consortia based on the drop collapse test was determined by 16S-rDNA pyrotag screening. Subsequently, the effect of incubation time, temperature, substrate and supplementation with inorganic nutrients, on BS production, was examined. Two types of BS – lipid mixtures were extracted from the culture broth; the low molecular weight BS Rhamnolipids and Sophorolipids. Crude extracts were purified by silica gel column chromatography and then identified by thin layer chromatography and Fourier transform infrared spectroscopy. Results indicate that BS production yield remains constant and low while it is independent of the total culture biomass, carbon source, and temperature. A constant BS concentration in a culture broth with continuous degradation of crude oil (CO) implies that the BS producing microbes generate no more than the required amount of BSs that enables biodegradation of the CO. Isolated pure strains were found to have higher specific production yields than the complex microbial marine community-consortia. The heavy oil fraction of CO has emerged as a promising substrate for BS production (by marine BS producers) with fewer impurities in the final product. Furthermore, a particular strain isolated from sediments, Paracoccus marcusii, may be an optimal choice for bioremediation purposes as its biomass remains trapped in the hydrocarbon phase, not suffering from potential dilution effects by sea currents. PMID:25904907

Submerged-Culture Mycelia and Broth of the Maitake Medicinal Mushroom Grifola frondosa (Higher Basidiomycetes) Alleviate Type 2 Diabetes-Induced Alterations in Immunocytic Function.

PubMed

Chen, Ya-Hui; Lee, Chien-Hsing; Hsu, Tai-Hao; Lo, Hui-Chen

2015-01-01

Type 2 Diabetes mellitus (T2DM), a disease with impaired glucose, protein and lipid metabolism, low-grade chronic inflammation, and immune dysfunction, is a global public health crisis. We previously demonstrated that Grifola frondosa has bioactivities in improving glycemic responses in diabetic rats. Herein, we investigated the immunomodulatory effects of the submerged-culture mycelia and broth of G. frondosa on the peripheral blood cells (PBL) and splenocytes. Male Wistar rats were administered with saline (normal rats) or streptozotocin plus nicotinamide (T2DM rats) and were intragastrically administered with placebo, fermented mycelia, broth, or mycelia plus broth (1 g kg-1 day-1) for two weeks. In normal rats, ingestion of mycelia significantly decreased monocytes and ingestion of mycelia and broth significantly decreased the productions of interferon (IFN)-γ and interleukin (IL)-4 from the PBL and splenocytes. In T2DM rats, ingestion of mycelia, broth, and mycelia plus broth significantly alleviated the increases in 2 h postprandial blood glucose and the productions of IFN-γ from the T-leukocytes, IL-4, and IL-6 from the monocytes and IL-4 from the T-splenocytes, as well as significantly improved the productions of tumor-necrosis factor-α from the macrophages. In conclusion, submerged-culture mycelia and broth of G. frondosa may decrease cell-medicated immunity in normal rats and improve hyperglycemia and diabetes-induced alterations in cell-medicated and innate immunities in T2DM rats.

Effect of Sucrose Stearate on the Sensory-Related Quality of the Broth and Porridge of Ready-To-Eat Ginseng Chicken Soup Samgyetang

PubMed Central

Triyannanto, Endy

2017-01-01

The objective of this study was to assess the sensory-related characteristics of the broth and porridge of ready-to-eat (RTE) ginseng chicken soup (Samgyetang) with sucrose stearate added at various concentrations (0.1%, 0.2%, and 0.3%) during storage at 25°C for 12 mon. Scores indicating the lightness and size of fat droplets in the broth increased during storage as the sucrose stearate concentration increased, while the clarity scores decreased until 9 mon and the taste scores decreased throughout the storage period (p<0.05). The porridge lightness increased as the concentration of sucrose stearate increased after 6 mon (p<0.05), while scores indicating the softness and vividness were higher for treated samples with sucrose stearate than for the control group after 3 mon, despite a lack of significant differences among treatment groups (p >0.05). The taste scores were lower for treated porridge samples than for the control group (p<0.05), even though no significant differences were observed among the treatment groups (p >0.05). The addition of sucrose stearate to the RTE Samgyetang broth improved the lightness (CIE L*) value of the broth and various sensory palatability parameters, including the color and fat droplet size of the broth and the softness and vividness of the porridge, despite reductions in broth clarity and taste scores for the broth and porridge during storage. PMID:29725207

Effect of Sucrose Stearate on the Sensory-Related Quality of the Broth and Porridge of Ready-To-Eat Ginseng Chicken Soup Samgyetang.

PubMed

Triyannanto, Endy; Lee, Keun Taik

2017-01-01

The objective of this study was to assess the sensory-related characteristics of the broth and porridge of ready-to-eat (RTE) ginseng chicken soup ( Samgyetang ) with sucrose stearate added at various concentrations (0.1%, 0.2%, and 0.3%) during storage at 25°C for 12 mon. Scores indicating the lightness and size of fat droplets in the broth increased during storage as the sucrose stearate concentration increased, while the clarity scores decreased until 9 mon and the taste scores decreased throughout the storage period ( p <0.05). The porridge lightness increased as the concentration of sucrose stearate increased after 6 mon ( p <0.05), while scores indicating the softness and vividness were higher for treated samples with sucrose stearate than for the control group after 3 mon, despite a lack of significant differences among treatment groups ( p >0.05). The taste scores were lower for treated porridge samples than for the control group ( p <0.05), even though no significant differences were observed among the treatment groups ( p >0.05). The addition of sucrose stearate to the RTE Samgyetang broth improved the lightness (CIE L *) value of the broth and various sensory palatability parameters, including the color and fat droplet size of the broth and the softness and vividness of the porridge, despite reductions in broth clarity and taste scores for the broth and porridge during storage.

Body composition among Sri Lankan infants by 18*O dilution method and the validity of anthropometric equations to predict body fat against 18*O dilution

USDA-ARS?s Scientific Manuscript database

Body composition indicators provide a better guidance for growth and nutritional status of the infants. This study was designed to (1) measure the body composition of the Sri Lankan infants using a reference method, the 18*O dilution method; (2) calculate the body fat content of the infants using pu...

Methods for deoxygenating biomass-derived pyrolysis oil

DOEpatents

Brandvold, Timothy A.

2015-07-14

Methods for deoxygenating a biomass-derived pyrolysis oil are provided. A method comprising the steps of diluting the biomass-derived pyrolysis oil with a phenolic-containing diluent to form a diluted pyoil-phenolic feed is provided. The diluted pyoil-phenolic feed is contacted with a deoxygenating catalyst in the presence of hydrogen at hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil effluent.

Chemical composition and antifungal activity of Arnica longifolia, Aster hesperius, and Chrysothamnus nauseosus essential oils.

PubMed

Tabanca, Nurhayat; Demirci, Betul; Crockett, Sara L; Başer, Kemal Hüsnü Can; Wedge, David E

2007-10-17

Essential oils from three different Asteraceae obtained by hydrodistillation of aerial parts were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). Main compounds obtained from each taxon were found as follows: Arnica longifolia carvacrol 37.3%, alpha-bisabolol 8.2%; Aster hesperius hexadecanoic acid 29.6%, carvacrol 15.2%; and Chrysothamnus nauseosus var. nauseosus beta-phellandrene 22.8% and beta-pinene 19.8%. Essential oils were also evaluated for their antimalarial and antimicrobial activity against human pathogens, and antifungal activities against plant pathogens. No antimalarial and antimicrobial activities against human pathogens were observed. Direct bioautography demonstrated antifungal activity of the essential oils obtained from three Asteraceae taxa and two pure compounds, carvacrol and beta-bisabolol, to the plant pathogens Colletotrichum acutatum, C. fragariae and C. gloeosporioides. Subsequent evaluation of antifungal compounds using a 96-well micro-dilution broth assay indicated that alpha-bisabolol showed weak growth inhibition of the plant pathogen Botrytis cinerea after 72 h.

Cytotoxic and antifungal activities of melleolide antibiotics follow dissimilar structure-activity relationships.

PubMed

Bohnert, Markus; Nützmann, Hans-Wilhelm; Schroeckh, Volker; Horn, Fabian; Dahse, Hans-Martin; Brakhage, Axel A; Hoffmeister, Dirk

2014-09-01

The fungal genus Armillaria is unique in that it is the only natural source of melleolide antibiotics, i.e., protoilludene alcohols esterified with orsellinic acid or its derivatives. This class of natural products is known to exert antimicrobial and cytotoxic effects. Here, we present a refined relationship between the structure and the antimicrobial activity of the melleolides. Using both agar diffusion and broth dilution assays, we identified the Δ(2,4)-double bond of the protoilludene moiety as a key structural feature for antifungal activity against Aspergillus nidulans, Aspergillus flavus, and Penicillium notatum. These findings contrast former reports on cytotoxic activities and may indicate a different mode of action towards susceptible fungi. We also report the isolation and structure elucidation of five melleolides (6'-dechloroarnamial, 6'-chloromelleolide F, 10-hydroxy-5'-methoxy-6'-chloroarmillane, and 13-deoxyarmellides A and B), along with the finding that treatment with an antifungal melleolide impacts transcription of A. nidulans natural product genes. Copyright © 2014 Elsevier Ltd. All rights reserved.

The chemical composition, antimicrobial, and antioxidant activities of Pycnocycla spinosa and Pycnocyla flabellifolia essential oils.

PubMed

Mahboubi, Mohaddese; Mahdizadeh, Elaheh; Heidary Tabar, Rezvan

2016-11-01

The purpose of our study was to compare the chemical compositions and antimicrobial and antioxidant activities of Pycnocycla spinosa and Pycnocycla flabellifolia essential oils. cis-Asarone (62.5%) and widdra-2,4(14)-diene (9%) were the main components of P. spinosa aerial part essential oil, while elemicin (60.1%) and caryophyllene oxide (9.8%) were the main components of P. spinosa seed essential oil. α-Phellandrene (25.5%), p-cymene (15.3%), and limonene (13.3%) were found in P. flabellifolia essential oil. The inhibition zone diameters for P. flabellifolia essential oil were significantly higher than for the two other essential oils from P. spinosa (p<0.05). In broth dilution assay (µL/mL), the sensitive microorganism to Pycnocycla sp. (P. spinosa, P. flabellifolia) was Aspergillus niger, followed by Candida albicans. In 2,2-diphenyl-1-picrylhydrazyl (DPPH) system, P. spinosa aerial parts essential oil (IC50=548 µg/mL) had higher antioxidant activity than that of two other essential oils.

An evaluation of bacterial contamination of barriers used in periapical tissue regeneration: Part 1--Bacterial adherence.

PubMed

Sharma, Priya; Mickel, André K; Chogle, Sami; Sharma, Prem Nath; Han, Yiping W; Jones, Jefferson J

2008-02-01

To compare the adherence of Prevotella melaninogenica and Enterococcus faecalis to 3 guided tissue regeneration membranes: Atrisorb, Lambone, and OsseoQuest. It was hypothesized that OsseoQuest would show increased bacterial adherence compared to Lambone and Atrisorb. The barriers were suspended in trypticase soy broth containing an inoculum of either P melaninogenica or E faecalis. The samples were incubated under appropriate conditions for 6, 24, and 48 hours. Following incubation, each membrane was mixed in fresh media in a vortex machine to dislodge adherent bacteria. The vortexed media was quantitatively assessed using serial dilutions for viable cell count. E faecalis exhibited higher adherence compared to P melaninogenica with time. Of the membranes tested, Lambone displayed the least bacterial adherence. An analysis of the results indicated that bacterial adherence was time-dependent for all membranes. Membrane structure, chemical configuration, hydrophobicity, and bacterial cell surface structure were suggested as factors contributing to variance in bacterial adherence.

Synthesis of new Schiff bases bearing 1,2,4-triazole, thiazolidine and chloroazetidine moieties and their pharmacological evaluation.

PubMed

Kandile, Nadia G; Mohamed, Mansoura I; Ismaeel, Hind M

2017-12-01

New compounds based on oxindole moiety were synthesized via the reaction of 5-substitued isatins 1a-e with different nucleophiles such as benzidine, 3,3'-dimethoxybenzidine 2a,b and 2,6-diaminopyridine 3 to afford three different classes of bis-Schiff bases 4a-e, 5a-e and 6a-e, respectively. The structures of the new compounds were elucidated on the basis of their FTIR, 1 H NMR, 13 C NMR, GC/MS spectral data and elemental analysis. The in vitro antimicrobial activity of the new compounds was evaluated using a broth dilution technique in terms of minimal inhibitory concentration (MIC) against four bacterial and two fungal pathogens and anticancer activities against HELA cervix. The revealed data showed that compound 9d has excellent activity against Gram + ve and Gram -ve bacteria, and compounds 11b presented promising anticancer activity against HELA cervix. [Formula: see text].

Antidermatophytic Properties of Ar-Turmerone, Turmeric Oil, and Curcuma longa Preparations.

PubMed

Jankasem, Mukda; Wuthi-Udomlert, Mansuang; Gritsanapan, Wandee

2013-01-01

Curcuma longa L. or turmeric of the family Zingiberaceae is widely used in Thai traditional medicines for the treatment of rash, itching, tinea, and ringworm. Previous studies on turmeric oil reported effective antifungal activity against dermatophytes, a group of fungi that causes skin diseases. In this study, turmeric creams containing 6 and 10% w/w turmeric oil were prepared and tested against clinical strains of dermatophytes using broth dilution technique. Minimum fungicidal concentrations of 6 and 10% w/w turmeric creams were found to be 312  μ g/mL. Ar-turmerone, a major compound separated from turmeric oil, promoted more effective antidermatophytic activity with the MICs of 1.56-6.25  μ g/mL, compared to 3.90-7.81  μ g/mL of standard ketoconazole. The results indicated that 6% w/w turmeric oil in the cream was suitable to be formulated as antidermatophytic preparation. Further research should be done on long-term chemical and antifungal stabilities of the preparation.

In Vitro Studies of Semisynthetic α- (Substituted-Ureido) Penicillins

PubMed Central

Bodey, Gerald P.; Stewart, Dorothy

1971-01-01

The activity of three α-(substituted-ureido) penicillins was evaluated in vitro against 599 clinical isolates of gram-negative bacilli, by use of the broth-dilution technique. At a concentration of 12.5 μg or less/ml, BL-P1597 inhibited 90% of isolates of Pseudomonas sp., 56% of Enterobacter sp., 67% of indole-positive Proteus spp., 72% of Escherichia coli, and 85% of Proteus mirabilis. BL-P1654 had similar activity, whereas BL-P1532 was much less active. At a concentration of 25 μg or less/ml, BL-P1597 also inhibited nearly 60% of isolates of Klebsiella sp. and nearly 40% of Serratia sp. BL-P1597 and BL-P1654 were as active as ampicillin and carbenicillin against E. coli and P. mirabilis. They were less active than carbenicillin against indole-positive Proteus spp. Both drugs were substantially more active than carbenicillin against Pseudomonas sp. A strain of Pseudomonas sp. which developed resistance to carbenicillin also developed resistance to the α-(substituted-ureido) penicillins simultaneously. PMID:4930281

Chemical composition and in vitro antioxidant and antibacterial activity of Heracleum transcaucasicum and Heracleum anisactis roots essential oil

PubMed Central

Torbati, Mohammadali; Nazemiyeh, Hossein; Lotfipour, Farzaneh; Nemati, Mahboob; Asnaashari, Solmaz; Fathiazad, Fatemeh

2014-01-01

Introduction: In vitro antioxidant and antibacterial activity and volatile compositions of two Heracleum species (Apiaceae) including Heracleum transcaucasicum and Heracleum anisactis roots Essential Oil (EO) were investigated. Methods: The volatile compositions of EOs were analyzed by GC/Mass spectroscopy. To detect the antioxidant activity of essential oils TLC-bioautography and DPPH radical scavenging assay by spectrophotometry was performed. Additionally, the antibacterial activity of two essential oils were studied and compared against four pathogenic bacteria by agar disc diffusion method and MIC values of the EOs were determined using the broth dilution method. Results: Myristicin was the dominant component in both EOs. It was identified as 96.87% and 95.15% of the essential oil composition of H. transcaucasicum and H. anisactis roots, respectively. The TLC-bioautography showed antioxidant spots in both EOs and IC50 of H. anisactis and H. transcaucasicum EO was found to be 54 μg × ml (-1) and 77 μg × ml (-1), respectively. Regarding the antimicrobial assay, H. anisactis EO exhibited weak to moderate antibacterial activity against gram-positive bacteria and also Escherichia coli, whereas the essential oil from H. transcaucasicum was inactive. Conclusion: Based on the results from this study, both tested EOs mainly consist of myristicin. Despite the presence of myristicin with known antibacterial property, the EO from H. transcacausicum showed no antibacterial activity. Thus it is supposed that the biological activity of plants is remarkably linked to the extracts’ chemical profile and intercomponents’ synergistic or antagonistic effect could play a crucial role in bioactivity of EOs and other plant extracts. PMID:25035849

The Antimicrobial Activities of Extract and Compounds Isolated from Brillantaisia lamium

PubMed Central

Tamokou, Jean De Dieu; Kuiate, Jules Roger; Tene, Mathieu; Kenla Nwemeguela, Timothée Julbelin; Tane, Pierre

2011-01-01

Background: Brillantaisia lamium is an erect branched herb, which grows to a height of 1.50 m in moist tropical areas, both in full sun and partial shade. In , the aerial part of this plant is used in the treatment of various microbial infections such as skin diseases and infections of urinary tract. The aim of this study was to evaluate the antimicrobial activities of CH2Cl2: MeOH (1:1) extract, fractions and compounds from the aerial part of B. lamium. Methods: The plant was dried and extracted by maceration in CH2Cl2: MeOH (1:1 v/v). Structures of the compounds from the CH2Cl2: MeOH (1:1) soluble fraction were determined by spectroscopic methods and compared with published data. The broth micro dilution method was used to evaluate the antimicrobial activities against bacteria and fungal species. Results: Four known compounds: aurantiamide acetate (1), lupeol (2), lespedin (3), sitosterol 3-O-β-D-glucopyranoside (4) and a mixture of sterols: campesterol (5), stigmasterol (6) and β-sitosterol (7) were isolated from CH2Cl2: MeOH (1:1) extract of B. lamium aerial parts. The crude extract, fractions and isolated compounds exhibited both antibacterial and antifungal activities that varied with microorganism (MIC=6.25 – 1000 µg/ml). Compound 3 was the most active (MIC=6.25 – 100 µg/ml) while Staphylococcus aureus, Enterococcus faecalis, Candida tropicalis and Cryptococcus neoformans were the most sensitive to all the tested compounds. Conclusion: The overall results of this study indicate that the CH2Cl2: MeOH (1:1) extract and some of isolated compounds have interesting antimicrobial properties and can be used for the treatment of fungal and bacterial infections. PMID:23365474

Black Zira essential oil: Chemical compositions and antimicrobial activity against the growth of some pathogenic strain causing infection.

PubMed

Noshad, Mohammad; Hojjati, Mohammad; Alizadeh Behbahani, Behrooz

2018-03-01

The aim of this study was to perform chemical compositions and phytochemical analysis of Black Zira essential oil and other goal of this research was to investigate the antimicrobial effects of Black Zira essential oil against Enterobacter aerogenes, Pseudomonas aeruginosa, Escherichia coli, Shigella flexneri, Staphylococcus epidermidis, Streptococcus pyogenes and Candida albicans. Black Zira essential oil was extracted by hydrodistillation method using clevenger apparatus. Black Zira essential oil chemical composition was identified through gas chromatography/mass spectrometry. γ-terpinene with a percentage of 24.8% was the major compound of Black Zira essential oil. The antimicrobial effect Black Zira essential oil was evaluated by several qualitative and quantitative methods (disk diffusion, well diffusion, microdilution broth, agar dilution and minimum bactericidal/fungicidal concentration). Phytochemical analysis Black Zira essential oil were appraised based on qualitative methods. Antioxidant activity (2,2-diphenyl-1-picrylhydrazyl and β-carotene/linoleic acid inhibition) and total phenolic content (Folin-Ciocalteu) were examined. The results of phytochemical analysis of Black Zira essential oil showed the existence of phenolic, flavonoids, saponins, alkaloids and tannins. The total phenolic content and antioxidant activity (reported as IC 50 ) of Black Zira essential oil were equal to 120.50 ± 0.50 mg GAE/g and 11.55 ± 0.25 μg/ml, respectively. The MIC of the Black Zira essential oil ranged from 1 mg/ml to 8 mg/ml, while its MBC and MFC ranged from 1 mg/ml to 16 mg/ml. The results presented that the longest and the shortest inhibition zone diameter at the concentration of 8 mg/ml pertained to C. albicans and E. aerogenes, respectively. Copyright © 2018. Published by Elsevier Ltd.

Isolation and genetic characterization of metallo-β-lactamase and carbapenamase producing strains of Acinetobacter baumannii from patients at Tehran hospitals

PubMed Central

Shahcheraghi, F; Abbasalipour, M; Feizabadi, MM; Ebrahimipour, GH; Akbari, N

2011-01-01

Background and Objective Carbapenems are therapeutic choice against infections caused by gram-negative bacilli including strains of Acinetobacter baumannii. Resistance to these antibiotics is mediated by efflux pumps, porins, PBPs and ß-lactamases. The aim of this study was to determine the possibility of existence of MBLs, OXAs and GES-1 betalactamase genes among clinical isolates of Acinetobacter collected from Tehran hospitals. Material and Methods Two hundred and three Acinetobacter isolates were collected from patient at Tehran hospitals. The isolates were identified using biochemical tests. The susceptibility to different antibiotics was evaluated by disk diffusion method and MICs of imipenem were determined using Micro broth dilution method (CLSI). PCR was performed for detection of bla VIM-2, bla SPM-1, bla IMP-2, bla GES-1, bla OXA-51, bla OXA-23 betalactamase genes. Clonal relatedness was estimated by PFGE with the restriction enzyme SmaI. Results and Conclusion Of 100 isolates of imipenem resistant Acinetobacter spp. collected from Tehran hospitals in 2009 and 2010, 6 isolates produced metallo-beta-lactamases and 94 isolates produced OXA-type carbapenemase. The bla SPM-1, bla GES-1, bla OXA-51, bla OXA-23 genes were detected by PCR among 6, 2, 94 and 84 isolates of A. baumannii, respectively. The MICs of isolates to imipenem were 8–128 µg/mL. PFGE analysis of 29 bla OXA-51 and bla OXA-23-positive A. baumannii isolates gave 6 different patterns. This is the first report of SPM-1 and GES-1 beta-lactamase producing A. baumannii. Production of the OXA-23, OXA-51, GES-1 and SPM-1 enzyme presents an emerging threat of carbapenem resistance among A. baumannii in Iran. PMID:22347585

Atlas(®) Listeria monocytogenes LmG2 Detection Assay Using Transcription Mediated Amplification to Detect Listeria monocytogenes in Selected Foods and Stainless Steel Surface.

PubMed

Bres, Vanessa; Yang, Hua; Hsu, Ernie; Ren, Yan; Cheng, Ying; Wisniewski, Michele; Hanhan, Maesa; Zaslavsky, Polina; Noll, Nathan; Weaver, Brett; Campbell, Paul; Reshatoff, Michael; Becker, Michael

2014-01-01

The Atlas Listeria monocytogenes LmG2 Detection Assay, developed by Roka Bioscience Inc., was compared to a reference culture method for seven food types (hot dogs, cured ham, deli turkey, chicken salad, vanilla ice cream, frozen chocolate cream pie, and frozen cheese pizza) and one surface (stainless steel, grade 316). A 125 g portion of deli turkey was tested using a 1:4 food:media dilution ratio, and a 25 g portion for all other foods was tested using 1:9 food:media dilution ratio. The enrichment time and media for Roka's method was 24 to 28 h for 25 g food samples and environmental surfaces, and 44 to 48 h for 125 g at 35 ± 2°C in PALCAM broth containing 0.02 g/L nalidixic acid. Comparison of the Atlas Listeria monocytogenes LmG2 Detection Assay to the reference method required an unpaired approach. For each matrix, 20 samples inoculated at a fractional level and five samples inoculated at a high level with a different strain of Listeria monocytogenes were tested by each method. The Atlas Listeria monocytogenes LmG2 Detection Assay was compared to the Official Methods of Analysis of AOAC INTERNATIONAL 993.12 method for dairy products, the U.S. Department of Agriculture, Food Safety and Inspection Service, Microbiology Laboratory Guidebook 8.08 method for ready-to-eat meat and environmental samples, and the U.S. Food and Drug Administration Bacteriological Analytical Manual, Chapter 10 method for frozen foods. In the method developer studies, Roka's method, at 24 h (or 44 h for 125 g food samples), had 126 positives out of 200 total inoculated samples, compared to 102 positives for the reference methods at 48 h. In the independent laboratory studies, vanilla ice cream, deli turkey and stainless steel grade 316 were evaluated. Roka's method, at 24 h (or 44 h for 125 g food samples), had 64 positives out of 75 total inoculated samples compared to 54 positives for the reference methods at 48 h. The Atlas Listeria monocytogenes LmG2 Detection Assay detected all 50 L. monocytogenes strains that encompassed 13 serotypes across the various lineages and none of the 30 exclusive organisms, including seven other Listeria species. The product consistency and kit stability studies revealed no statistical differences between the three lots tested or to the term of the shelf life. Finally, the robustness study demonstrated no statistical differences when samples were incubated at 33 ± 2°C or 37 ± 2°C, when enrichment aliquots were 1.3 mL or 1.7 mL, or when the samples were analyzed the same day or five days later. Overall the Atlas Listeria monocytogenes LmG2 Detection Assay is statistically equivalent to or better than the reference methods and is robust to the tested variations.

40 CFR 141.21 - Coliform sampling.

Code of Federal Regulations, 2011 CFR

2011-07-01

... transit. 3 Lactose broth, as commercially available, may be used in lieu of lauryl tryptose broth, if the... total coliform, using lactose broth, is less than 10 percent. 4 If inverted tubes are used to detect gas... negative-rates may be based on lactose fermentation, the rapid test for β-galactosidase and cytochrome...

40 CFR 141.21 - Coliform sampling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... transit. 3 Lactose broth, as commercially available, may be used in lieu of lauryl tryptose broth, if the... total coliform, using lactose broth, is less than 10 percent. 4 If inverted tubes are used to detect gas... negative-rates may be based on lactose fermentation, the rapid test for β-galactosidase and cytochrome...

Limitations of Thioglycolate Broth as a Sterility Test Medium for Materials Exposed to Gaseous Ethylene Oxide1

PubMed Central

Doyle, John E.; Mehrhof, William H.; Ernst, Robert R.

1968-01-01

Although ethylene oxide is a reliable sterilizer, the process may be limited by diffusion. Thus, situations may exist where microorganisms are protected from the sterilizing gas. It is possible that the exterior of a substance may be sterilized, whereas the interior is not. We investigated three general types of materials in which this limitation of diffusion could occur: the bore of glass and plastic tubing, the center of cotton balls, and plastic adhesive film/paper backing interface. These materials were contaminated as close to their geometric center as possible with Bacillus subtilis var. niger spores occluded in crystals of sodium chloride. After exposure of the contaminated materials (except aluminum foil) to ethylene oxide, thioglycolate broth (a standard sterility-test medium) indicated sterility, whereas Trypticase Soy Broth indicated nonsterility. It is likewise possible that aerobic microorganisms, surviving in or on material after exposure to dry heat or steam sterilization processes, would not be recovered by thioglycollate broth. Entrapped aerobic organisms will probably not grow out in the low oxygen tension zone of an anaerobic medium such as thioglycollate broth. It is recommended than an aerobic medium such as Trypticase Soy Broth be used concurrently with thioglycolate broth for sterility testing. PMID:4973064

Antimicrobial Activity of Seven Essential Oils From Iranian Aromatic Plants Against Common Causes of Oral Infections

PubMed Central

Zomorodian, Kamiar; Ghadiri, Pooria; Saharkhiz, Mohammad Jamal; Moein, Mohammad Reza; Mehriar, Peiman; Bahrani, Farideh; Golzar, Tahereh; Pakshir, Keyvan; Fani, Mohammad Mehdi

2015-01-01

Background: Over the past two decades, there has been a growing trend in using oral hygienic products originating from natural resources such as essential oils (EOs) and plant extracts. Seven aromatic plants used in this study are among popular traditional Iranian medicinal plants with potential application in modern medicine as anti-oral infectious diseases. Objectives: This study was conducted to determine the chemical composition and antimicrobial activities of essential oils from seven medicinal plants against pathogens causing oral infections. Materials and Methods: The chemical compositions of EOs distilled from seven plants were analyzed by gas chromatography/mass spectrometry (GC/MS). These plants included Satureja khuzestanica, S. bachtiarica, Ocimum sanctum, Artemisia sieberi, Zataria multiflora, Carum copticum and Oliveria decumbens. The antimicrobial activity of the essential oils was evaluated by broth micro-dilution in 96 well plates as recommended by the Clinical and Laboratory Standards Institute (CLSI) methods. Results: The tested EOs inhibited the growth of examined oral pathogens at concentrations of 0.015-16 µL/mL. Among the examined oral pathogens, Enterococcus faecalis had the highest Minimum Inhibitory Concentrations (MICs) and Minimum Microbicidal Concentrations (MMCs). Of the examined EOs, S. khuzestanica, Z. multiflora and S. bachtiarica, showed the highest antimicrobial activities, respectively, while Artemisia sieberi exhibited the lowest antimicrobial activity. Conclusions: The excellent antimicrobial activities of the tested EOs might be due to their major phenolic or alcoholic monoterpenes with known antimicrobial activities. Hence, these EOs can be possibly used as an antimicrobial agent in treatment and control of oral pathogens. PMID:25793100

Inhibition of Serratia marcescens Smj-11 biofilm formation by Alcaligenes faecalis STN17 crude extract

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

Lutfi, Zainal; Ahmad, Asmat; Usup, Gires

Serratia marcescens biofilms are formed when they are bound to surfaces in aqueous environments. S. marcescens utilizes N-acylhomoserine lactone (AHL) as its quorum sensing signal molecule. The accumulation of AHL indicates the bacteria to produce matrices to form biofilms. Prodigiosin (2-methyl-3-pentyl-6-methoxyprodigiosin), which causes red pigmentation in the colonies, are also produced when the AHL reaches a certain threshold. The Alcaligenes faecalis STN17 crude extract is believed to inhibit quorum sensing in the S. marcescens Smj-11 and, thus, impedes its biofilm formation ability. A. faecalis STN17 was grown in marine broth, and ethyl acetate extraction was carried out. The crude compoundmore » of A. faecalis STN17 was diluted at high concentration (0.2-6.4 mg/mL) and was taken to confirm anti-biofilm activity through the crystal violet method in 96-wells plate. Then, the crude extract underwent purification using simple solvents partitioning test to discern the respective compounds that had the anti-biofilm activity under the crystal violet method. The crystal violet test showed that the crude did have anti-biofilm activity on S. marcescens Smj-11, but did not kill the cells. This finding signifies that the suppression of biofilm formation in S. marcescens by A. faecalis STN17 has a strong correlation. The partitioning test showed that A. faecalis STN17 crude extract has several compounds and only the compound(s) in chloroform showed activities. In conclusion, the crude extract of A. faecalis STN17 has the ability to inhibit S. marcescens Smj-11 biofilm formation.« less

Evaluation of the effect of Cassia surattensis Burm. f., flower methanolic extract on the growth and morphology of Aspergillus niger.

PubMed

Sumathy, V; Zakaria, Z; Chen, Y; Latha, L Y; Jothy, S L; Vijayarathna, S; Sasidharan, S

2013-06-01

Cassia (C.) surattensis Burm. f. (Leguminosae), a medicinal herb native to tropical equatorial Asia, was commonly used in folk medicine to treat various diseases. The aim of the present study is to investigate the effects of methanolic flower extract of C. surattensis against Aspergillus (A.) niger. Antifungal activity of C. surattensis flower extract was studied by using agar disc diffusion method, broth dilution method, percentage of hyphal growth inhibition and scanning electron microscopy (SEM) observation. The extract exhibited good antifungal activity with zone of inhibition 15 mm and minimum inhibitory concentration (MIC) 6.25 mg/ml. The flower extract exhibited considerable antifungal activity against A. niger with a IC50 of 2.49 mg/ml on the hyphal growth. In scanning electron microscopy (SEM) squashed, collapsed, empty and deformation of hyphae were the major changes observed. Shrunken conidiophores were the obvious alteration on the spores. Morphological alterations observed on A. niger caused by the flower extract could be the contribution of chemical compounds present in the Cassia flower. Phytochemical screening reveals the presence of carbohydrate, tannins, saponins and phenols in the extract. The amount of tannin, total phenolics and flavonoids were estimated to be 55.14 ± 3.11 mg/g, 349.87 ± 5.41 mg/g gallic acid equivalent and 89.64 ± 3.21 mg/g catechin equivalent respectively. C. surattensis flower extract potently inhibited the growth of A. niger and are, therefore, excellent candidates for use as the lead compounds for the development of novel antifungal agents.

Antifungal activity of Curcuma longa grown in Thailand.

PubMed

Wuthi-udomlert, M; Grisanapan, W; Luanratana, O; Caichompoo, W

2000-01-01

Curcuma longa Linn. or turmeric (Zingiberaceae) is a medicinal plant widely used and cultivated in tropical regions. According to Thai traditional texts, fresh and dried rhizomes are used as peptic ulcer treatment, carminatives, wound treatment and anti-inflammatory agent. Using hydro distillation, 1.88% and 7.02% (v/w) volatile oils were extracted from fresh and dried rhizomes, respectively, and 6.95% (w/w)crude curcuminoids were extracted from dried rhizomes. Dried powder was extracted with 95% ethanol and yielded 29.52% (w/w) crude ethanol extract composed of curcumin (11.6%), demethoxycurcumin (10.32%) and bisdemethoxycurcumin (10.77%). These extracts were tested for antifungal activity by agar disc diffusion method against 29 clinical strains of dermatophytes. It was found that crude ethanol extract exhibited an inhibition zone range of 6.1 to 26.0 mm. There was no inhibition activity from crude curcuminoids while curcumin, demethoxycurcumin and bisdemethoxycutcumin gave different inhibition zone diameters ranging from 6.1 to 16.0 mm. Although antifungal activity of undiluted freshly distilled oil and 18-month-old oil revealed some differences, the inhibition zone diameters for both extracts varied within 26.1 to 46.0 mm. With 200 mg/ml ketoconazole, the activities of the standard agent were similar to the oil, both freshly distilled and 18-month-old, but were significantly different from those of curcuminoid compounds and crude ethanol extracts (p < 0.01). Turmeric oil was also tested for its minimum inhibitory concentration (MIC) by broth dilution method. The MICs of freshly distilled and 18-month-old oils were 7.8 and 7.2 mg/ml respectively.

Anti-methicillin-resistant Staphylococcus aureus (MRSA) activity of Rubiaceae, Fabaceae and Poaceae plants: A search for new sources of useful alternative antibacterials against MRSA infections.

PubMed

Sharifi-Rad, M; Iriti, M; Sharifi-Rad, M; Gibbons, S; Sharifi-Rad, J

2016-08-29

In this study, we evaluated the effects of the extracts of the leaves of species from the Rubiaceae (Galium aparine L. and Asperula arvensis L.), Fabaceae (Lathyrus aphaca L. and Vicia narbonensis L.) and Poaceae (Digitaria sanguinalis (L.) Scop. and Hordeum murinum L.) plant families on a wide and extensive panel of isolated methicillin-resistant Staphylococcus aureus strains (MRSA). The effects of the methanolic leaf extracts of Rubiaceae, Fabaceae and Poaceae plants on MRSA were evaluated by the disc diffusion assay and the broth dilution method. Among a total of 177 S. aureus isolates, 92 (51.97%) were found to be methicillin-resistant in an antibiogram and this was confirmed by the presence of the mecA gene in polymerase chain reaction method. All MRSA isolates were sensitive to all extracts. There were dose-dependent inhibitions on tested microorganisms for all plant extracts which showed maximum inhibition zones at a concentration of 300 mg/L. L. aphaca, G. aparine and H. murinum exhibited the highest antibacterial activity on the MRSA strains compared to the positive control (P < 0.05), as well as higher total polyphenol and flavonoid contents than other plant extracts. Minimum inhibitory concentrations on MRSA isolates ranged from 388.4 ± 0.2 mg/L, in D. sanguinalis, to 5.5 ± 0.1 mg/L, in L. aphaca. The methanolic extracts of L. aphaca (Fabaceae), G. aparine (Rubiaceae), and H. murinum (Poaceae) proved to have high antibacterial activity on MRSA isolates, thus representing promising antimicrobial agents in clinical settings.

Inhibition of Serratia marcescens Smj-11 biofilm formation by Alcaligenes faecalis STN17 crude extract

NASA Astrophysics Data System (ADS)

Lutfi, Zainal; Usup, Gires; Ahmad, Asmat

2014-09-01

Serratia marcescens biofilms are formed when they are bound to surfaces in aqueous environments. S. marcescens utilizes N-acylhomoserine lactone (AHL) as its quorum sensing signal molecule. The accumulation of AHL indicates the bacteria to produce matrices to form biofilms. Prodigiosin (2-methyl-3-pentyl-6-methoxyprodigiosin), which causes red pigmentation in the colonies, are also produced when the AHL reaches a certain threshold. The Alcaligenes faecalis STN17 crude extract is believed to inhibit quorum sensing in the S. marcescens Smj-11 and, thus, impedes its biofilm formation ability. A. faecalis STN17 was grown in marine broth, and ethyl acetate extraction was carried out. The crude compound of A. faecalis STN17 was diluted at high concentration (0.2-6.4 mg/mL) and was taken to confirm anti-biofilm activity through the crystal violet method in 96-wells plate. Then, the crude extract underwent purification using simple solvents partitioning test to discern the respective compounds that had the anti-biofilm activity under the crystal violet method. The crystal violet test showed that the crude did have anti-biofilm activity on S. marcescens Smj-11, but did not kill the cells. This finding signifies that the suppression of biofilm formation in S. marcescens by A. faecalis STN17 has a strong correlation. The partitioning test showed that A. faecalis STN17 crude extract has several compounds and only the compound(s) in chloroform showed activities. In conclusion, the crude extract of A. faecalis STN17 has the ability to inhibit S. marcescens Smj-11 biofilm formation.

In Vitro Comparison of Ertapenem, Meropenem, and Imipenem against Isolates of Rapidly Growing Mycobacteria and Nocardia by Use of Broth Microdilution and Etest.

PubMed

Brown-Elliott, Barbara A; Killingley, Jessica; Vasireddy, Sruthi; Bridge, Linda; Wallace, Richard J

2016-06-01

We compared the activities of the carbapenems ertapenem, meropenem, and imipenem against 180 isolates of rapidly growing mycobacteria (RGM) and 170 isolates of Nocardia using the Clinical and Laboratory Standards Institute (CLSI) guidelines. A subset of isolates was tested using the Etest. The rate of susceptibility to ertapenem and meropenem was limited and less than that to imipenem for the RGM. Analysis of major and minor discrepancies revealed that >90% of the isolates of Nocardia had higher MICs by the broth microdilution method than by Etest, in contrast to the lower broth microdilution MICs seen for >80% of the RGM. Imipenem remains the most active carbapenem against RGM, including Mycobacterium abscessus subsp. abscessus For Nocardia, imipenem was significantly more active only against Nocardia farcinica Although there may be utility in testing the activities of the newer carbapenems against Nocardia, their activities against the RGM should not be routinely tested. Testing by Etest is not recommended by the CLSI. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Comparison of gravimetric and a double-indicator dilution technique for assessment of extra-vascular lung water in endotoxaemia.

PubMed

Rossi, P; Oldner, A; Wanecek, M; Leksell, L G; Rudehill, A; Konrad, D; Weitzberg, E

2003-03-01

To compare a molecular double-indicator dilution technique with the gravimetrical reference method for measurement of extra-vascular lung water in porcine endotoxin shock. Open comparative experimental study. Animal research laboratory. In fourteen anaesthetised, mechanically ventilated landrace pigs, central and pulmonary haemodynamics as well as pulmonary gas exchange were measured. Extra-vascular lung water was quantitated gravimetrically as well as with a molecular double indicator dilution technique. Eight of these animals were subjected to endotoxaemia, the rest serving as sham controls. No difference in extra-vascular lung water was observed between the two methods in sham animals. Furthermore, extra-vascular lung water assessed with the molecular double-indicator dilution technique at the initiation of endotoxin infusion did not differ significantly from the corresponding values for sham animals. Endotoxaemia induced a hypodynamic shock with concurrent pulmonary hypertension and a pronounced deterioration in gas exchange. No increase in extra-vascular lung water was detected with the molecular double-indicator dilution technique in response to endotoxin, whereas this parameter was significantly higher when assessed with the gravimetric method. The molecular double-indicator dilution technique showed similar results as the gravimetrical method for assessment of extra-vascular lung water in non-endotoxaemic conditions. However, during endotoxin-induced lung injury the molecular double indicator dilution technique failed to detect the significant increase in extra-vascular lung water as measured by the gravimetric method. These data suggest that the molecular double indicator dilution technique may be of limited value during sepsis-induced lung injury.

Performance characteristics of broth-only cultures after revision total joint arthroplasty.

PubMed

Smith, Eric B; Cai, Jenny; Wynne, Rachael; Maltenfort, Mitchell; Good, Robert P

2014-11-01

Surgeons frequently obtain intraoperative cultures at the time of revision total joint arthroplasty. The use of broth or liquid medium before applying the sample to the agar medium may be associated with contamination and false-positive cultures; however, the degree to which this is the case is not known. We (1) calculated the performance characteristics of broth-only cultures (sensitivity, specificity, positive predictive value, and negative predictive value) and (2) characterized the organisms identified in broth to determine whether a specific organism showed increased proclivity for true-positive periprosthetic joint infection (PJI). A single-institution retrospective chart review was performed on 257 revision total joint arthroplasties from 2009 through 2010. One hundred ninety (74%) had cultures for review. All culture results, as well as treatment, if any, were documented and patients were followed for a minimum of 1 year for evidence of PJI. Cultures were measured as either positive from the broth only or broth negative. The true diagnosis of infection was determined by the Musculoskeletal Infection Society criteria during the preoperative workup or postoperatively at 1 year for purposes of calculating the performance characteristics of the broth-only culture. The sensitivity, specificity, positive predictive value, and negative predictive value were 19%, 88%, 13%, and 92%, respectively. The most common organism identified was coagulase-negative Staphylococcus (16 of 24 cases, 67%). Coagulase-negative Staphylococcus was present in all three true-positive cases; however, it was also found in 13 of the false-positive cases. The broth-only positive cultures showed poor sensitivity and positive predictive value but good specificity and negative predictive value. The good specificity indicates that it can help to rule in the presence of PJI; however, the poor sensitivity makes broth-only culture an unreliable screening test. We recommend that broth-only culture results be carefully scrutinized and decisions on the diagnosis and treatment of infection should be based specifically on the Musculoskeletal Infection Society criteria. Level IV, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.

A New Versatile Microarray-based Method for High Throughput Screening of Carbohydrate-active Enzymes*

PubMed Central

Vidal-Melgosa, Silvia; Pedersen, Henriette L.; Schückel, Julia; Arnal, Grégory; Dumon, Claire; Amby, Daniel B.; Monrad, Rune Nygaard; Westereng, Bjørge; Willats, William G. T.

2015-01-01

Carbohydrate-active enzymes have multiple biological roles and industrial applications. Advances in genome and transcriptome sequencing together with associated bioinformatics tools have identified vast numbers of putative carbohydrate-degrading and -modifying enzymes including glycoside hydrolases and lytic polysaccharide monooxygenases. However, there is a paucity of methods for rapidly screening the activities of these enzymes. By combining the multiplexing capacity of carbohydrate microarrays with the specificity of molecular probes, we have developed a sensitive, high throughput, and versatile semiquantitative enzyme screening technique that requires low amounts of enzyme and substrate. The method can be used to assess the activities of single enzymes, enzyme mixtures, and crude culture broths against single substrates, substrate mixtures, and biomass samples. Moreover, we show that the technique can be used to analyze both endo-acting and exo-acting glycoside hydrolases, polysaccharide lyases, carbohydrate esterases, and lytic polysaccharide monooxygenases. We demonstrate the potential of the technique by identifying the substrate specificities of purified uncharacterized enzymes and by screening enzyme activities from fungal culture broths. PMID:25657012

[Isolation of Campylobacter jejuni ATCC 29428 from inoculated fried pork meat and roasted chicken].

PubMed

Castillo-Martínez, M L; Sánchez-Sánchez, S; Rodríguez-Montaño, R; Quiñones-Ramírez, E I; Lugo de la Fuente, G; Vázquez-Salinas, C

1993-01-01

The human gastroenteritis caused by Campylobacter jejuni in some industrialized countries is higher than gastroenteritis produced by Salmonella and Shigella. This has induced the development of techniques to demonstrate the presence of the microorganism in different foods using some culture media combinations. There is not a method to isolate C. jejuni from roasted chicken and fried pork meat, which are popular foods in México. The sensitivity of two culture media combinations was compared: Rama broth (RB)-Rama agar (RA) and Preston broth (PB)-Skirrow agar (SA) to isolate C. jejuni from these foods. The RB-RA combination demonstrated to be the best one to isolate C. jejuni.

Selective enumeration of propionibacteria in Emmental-type cheese using Petrifilm™ aerobic count plates added to lithium glycerol broth.

PubMed

de Freitas, Rosângela; Luiz, Lívia M Pinheiro; Alves, Maura Pinheiro; Valence-Bertel, Florence; Nero, Luís Augusto; de Carvalho, Antônio Fernandes

2013-08-01

Propionibacteria derived from dairy products are relevant starter cultures for the production of Swiss and Emmental-type cheeses, and the monitoring of which is mandatory for proper quality control. This study aimed to evaluate an alternative procedure to enumerate propionibacteria, in order to develop a reliable and practical methodology to be employed by dairy industries. 2,3,5-triphenyltetrazolium chloride (TTC) inhibitory activity was tested against five reference strains (CIRM 09, 38, 39, 40 and 116); TTC at 0·0025% (w/v) was not inhibitory, with the exception of one strain (CIRM 116). Subsequently, the four TTC-resistant strains, three commercial starter cultures (PS-1, PB-I, and CHOO) and twelve Emmental-type cheese samples were subjected to propionibacteria enumeration using Lithium Glycerol (LG) agar, and Petrifilm™ Aerobic Count (AC) plates added to LG broth (anaerobic incubation at 30 °C for 7 d). Petrifilm™ AC added to LG broth presented high counts than LG agar (P<0·05) for only two reference strains (CIRM 39, and 40) and for all commercial starter cultures. Cheese sample counts obtained by both procedures did not show significant differences (P<0·05). Significant correlation indexes were observed between the counts recorded by both methods (P<0·05). These results demonstrate the reliability of Petrifilm™ AC plates added to LG broth in enumerating select Propionibacterium spp., despite some limitations observed for specific commercial starter cultures.

[Kinetic simulation of enhanced biological phosphorus removal with fermentation broth as carbon source].

PubMed

Zhang, Chao; Chen, Yin-Guang

2013-07-01

As a high-quality carbon source, fermentation broth could promote the phosphorus removal efficiency in enhanced biological phosphorus removal (EBPR). The transformation of substrates in EBPR fed with fermentation broth was well simulated using the modified activated sludge model No. 2 (ASM2) based on the carbon source metabolism. When fermentation broth was used as the sole carbon source, it was found that heterotrophic bacteria acted as a promoter rather than a competitor to the phosphorus accumulating organisms (PAO). When fermentation broth was used as a supplementary carbon source of real municipal wastewater, the wastewater composition was optimized for PAO growth; and the PAO concentration, which was increased by 3.3 times compared to that in EBPR fed with solely real municipal wastewater, accounting for about 40% of the total biomass in the reactor.

Ultra Scale-Down Characterization of the Impact of Conditioning Methods for Harvested Cell Broths on Clarification by Continuous Centrifugation—Recovery of Domain Antibodies from rec E. coli

PubMed Central

Chatel, Alex; Kumpalume, Peter; Hoare, Mike

2014-01-01

The processing of harvested E. coli cell broths is examined where the expressed protein product has been released into the extracellular space. Pre-treatment methods such as freeze–thaw, flocculation, and homogenization are studied. The resultant suspensions are characterized in terms of the particle size distribution, sensitivity to shear stress, rheology and solids volume fraction, and, using ultra scale-down methods, the predicted ability to clarify the material using industrial scale continuous flow centrifugation. A key finding was the potential of flocculation methods both to aid the recovery of the particles and to cause the selective precipitation of soluble contaminants. While the flocculated material is severely affected by process shear stress, the impact on the very fine end of the size distribution is relatively minor and hence the predicted performance was only diminished to a small extent, for example, from 99.9% to 99.7% clarification compared with 95% for autolysate and 65% for homogenate at equivalent centrifugation conditions. The lumped properties as represented by ultra scale-down centrifugation results were correlated with the basic properties affecting sedimentation including particle size distribution, suspension viscosity, and solids volume fraction. Grade efficiency relationships were used to allow for the particle and flow dynamics affecting capture in the centrifuge. The size distribution below a critical diameter dependant on the broth pre-treatment type was shown to be the main determining factor affecting the clarification achieved. Biotechnol. Bioeng. 2014;111: 913–924. © 2013 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. PMID:24284936

Diagnostic performance of blood culture bottles for vitreous culture compared to conventional microbiological cultures in patients with suspected endophthalmitis.

PubMed

Kehrmann, Jan; Chapot, Valerie; Buer, Jan; Rating, Philipp; Bornfeld, Norbert; Steinmann, Joerg

2018-05-01

The purpose of this investigation was to evaluate the performance of blood culture bottles in comparison to conventional microbiological culture techniques in detecting causative microorganisms of endophthalmitis and to determine their anti-infective susceptibility profiles. All consecutive cases with clinically suspected endophthalmitis in a university-based ophthalmology department between January 2009 and December 2016 were analysed in this retrospective comparative case series. Samples from 247 patients with suspected endophthalmitis underwent microbiological diagnostic work-up. All three culture methods were performed from 140 vitreous specimens. Vitreous fluid specimens were inoculated in blood culture bottles, aerobic and anaerobic broth solutions, and on solid media. Anti-infective susceptibility profiles were evaluated by semi-automated methods and/or gradient diffusion methods. Microorganisms were grown in 82 of 140 specimens for which all methods were performed (59%). Microorganisms were more frequently grown from blood culture bottles (55%) compared to broth solution (45%, p = 0.007) and solid media (33%, p < 0.0001). Considerable differences in the performance among culture media were detected for fungal pathogens. All grown fungi were detected by blood culture bottles (11 of 11, 100%). Broth solution recovered 64% and solid media 46% of grown fungi. No Gram-positive bacterium was resistant to vancomycin and all Gram-negative pathogens except for one isolate were susceptible to third-generation cephalosporins. In suspected endophthalmitis patients, blood culture bottles have a higher overall pathogen detection rate from vitreous fluid compared to conventional microbiological media, especially for fungi. The initial intravitreal antibiotic therapy with vancomycin plus third-generation cephalosporins appears to be an appropriate treatment approach for bacterial endophthalmitis.

Reducing agent can be omitted in the incubation medium of the batch in vitro fermentation model of the pig intestines.

PubMed

Poelaert, C; Nollevaux, G; Boudry, C; Taminiau, B; Nezer, C; Daube, G; Schneider, Y-J; Portetelle, D; Théwis, A; Bindelle, J

2018-06-01

Over the past decade, in vitro methods have been developed to study intestinal fermentation in pigs and its influence on the digestive physiology and health. In these methods, ingredients are fermented by a bacterial inoculum diluted in a mineral buffer solution. Generally, a reducing agent such as Na2S or cysteine-HCl generates the required anaerobic environment by releasing metabolites similar to those produced when protein is fermented, possibly inducing a dysbiosis. An experiment was conducted to study the impact of two reducing agents on results yielded by such in vitro fermentation models. Protein (soybean proteins, casein) and carbohydrate (potato starch, cellulose) ingredients were fermented in vitro by bacteria isolated from fresh feces obtained from three sows in three carbonate-based incubation media differing in reducing agent: (i) Na2S, (ii) cysteine-HCl and (iii) control with a mere saturation with CO2 and devoid of reducing agent. The gas production during fermentation was recorded over 72 h. Short-chain fatty acids (SCFA) production after 24 and 72 h and microbial composition of the fermentation broth after 24 h were compared between ingredients and between reducing agents. The fermentation residues after 24 h were also evaluated in terms of cytotoxicity using Caco-2 cell monolayers. Results showed that the effect of the ingredient induced higher differences than the reducing agent. Among the latter, cysteine-HCl induced the strongest differences compared with the control, whereas Na2S was similar to the control for most parameters. For all ingredients, final gas produced per g of substrate was similar (P>0.10) for the three reducing agents whereas the maximum rate of gas production (R max) was reduced (P0.10) after 24 h of fermentation with Na2S and in the control without reducing agent. Molar ratios of branched chain-fatty acids were higher (P<0.05) for protein (36.5% and 9.7% for casein and soybean proteins, respectively) than for carbohydrate (<4%) ingredients. Only fermentation residues of casein showed a possible cytotoxic effect regardless of the reducing agent (P<0.05). Concerning the microbial composition of the fermentation broth, most significant differences in phyla and in genera ascribable to the reducing agent were found with potato starch and casein. In conclusion, saturating the incubation media with CO2 seems sufficient to generate a suitable anaerobic environment for intestinal microbes and the use of a reducing agent can be omitted.

Factors influencing the potency of marbofloxacin for pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida.

PubMed

Dorey, L; Hobson, S; Lees, P

2017-04-01

For the pig respiratory tract pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida, Minimum Inhibitory Concentration (MIC) of marbofloxacin was determined in recommended broths and pig serum at three inoculum strengths. MICs in both growth matrices increased progressively from low, through medium to high starting inoculum counts, 10 4 , 10 6 and 10 8 CFU/mL, respectively. P. multocida MIC ratios for high:low inocula were 14:4:1 for broth and 28.2:1 for serum. Corresponding MIC ratios for A. pleuropneumoniae were lower, 4.1:1 (broth) and 9.2:1 (serum). MIC high:low ratios were therefore both growth matrix and bacterial species dependent. The effect of alterations to the chemical composition of broths and serum on MIC were also investigated. Neither adjusting broth or serum pH in six increments over the range 7.0 to 8.0 nor increasing calcium and magnesium concentrations of broth in seven incremental steps significantly affected MICs for either organism. In time-kill studies, the killing action of marbofloxacin had the characteristics of concentration dependency against both organisms in both growth matrices. It is concluded that MIC and time-kill data for marbofloxacin, generated in serum, might be preferable to broth data, for predicting dosages of marbofloxacin for clinical use. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rapid, Efficient Detection and Drug Susceptibility Testing of Mycobacterium tuberculosis in Sputum by Microscopic Observation of Broth Cultures

PubMed Central

Caviedes, Luz; Lee, Tien-Shun; Gilman, Robert H.; Sheen, Patricia; Spellman, Emily; Lee, Ellen H.; Berg, Douglas E.; Montenegro-James, Sonia

2000-01-01

Inexpensive, rapid, and reliable methods of detecting infection by and drug susceptibility of Mycobacterium tuberculosis (MTB) are crucial to the control of tuberculosis. The novel microscopic observation broth-drug susceptibility assay (MODS) detects early growth of MTB in liquid medium, allowing more timely diagnosis and drug susceptibility testing. Sputum samples from hospitalized patients in Peru were analyzed by using stains, culture, and PCR. Sensitivity of MODS (92%) compared favorably with the most sensitive of the other culture methods (93%). Sputum samples positive for tuberculosis were tested for susceptibility to isoniazid and rifampin with the microwell alamar blue assay (MABA) and MODS. In 89% of cases, there was concordance between MODS and MABA. Of the diagnostic and susceptibility testing methods used, MODS yielded results most rapidly (median, 9.0 and 9.5 days, respectively). MODS is a rapid, inexpensive, sensitive, and specific method for MTB detection and susceptibility testing; it is particularly appropriate for use in developing countries burdened by significant infection rates and increasing numbers of multiple-drug-resistant cases. PMID:10699023

Rapid, efficient detection and drug susceptibility testing of Mycobacterium tuberculosis in sputum by microscopic observation of broth cultures. The Tuberculosis Working Group in Peru.

PubMed

Caviedes, L; Lee, T S; Gilman, R H; Sheen, P; Spellman, E; Lee, E H; Berg, D E; Montenegro-James, S

2000-03-01

Inexpensive, rapid, and reliable methods of detecting infection by and drug susceptibility of Mycobacterium tuberculosis (MTB) are crucial to the control of tuberculosis. The novel microscopic observation broth-drug susceptibility assay (MODS) detects early growth of MTB in liquid medium, allowing more timely diagnosis and drug susceptibility testing. Sputum samples from hospitalized patients in Peru were analyzed by using stains, culture, and PCR. Sensitivity of MODS (92%) compared favorably with the most sensitive of the other culture methods (93%). Sputum samples positive for tuberculosis were tested for susceptibility to isoniazid and rifampin with the microwell alamar blue assay (MABA) and MODS. In 89% of cases, there was concordance between MODS and MABA. Of the diagnostic and susceptibility testing methods used, MODS yielded results most rapidly (median, 9.0 and 9.5 days, respectively). MODS is a rapid, inexpensive, sensitive, and specific method for MTB detection and susceptibility testing; it is particularly appropriate for use in developing countries burdened by significant infection rates and increasing numbers of multiple-drug-resistant cases.

New Eudesmane-Type Sesquiterpenoids from the Mangrove-Derived Endophytic Fungus Penicillium sp. J-54.

PubMed

Qiu, Liuming; Wang, Pei; Liao, Ge; Zeng, Yanbo; Cai, Caihong; Kong, Fandong; Guo, Zhikai; Proksch, Peter; Dai, Haofu; Mei, Wenli

2018-03-28

Four new eudesmane-type sesquiterpenoids, penicieudesmol A-D ( 1 - 4 ), were isolated from the fermentation broth of the mangrove-derived endophytic fungus Penicillium sp. J-54. Their structures were determined by spectroscopic methods, the in situ dimolybdenum CD method, and modified Mosher's method. The bioassays results showed that 2 exhibited weak cytotoxicity against K-562 cells.

Method of saccharifying cellulose

DOEpatents

Johnson, Eric A.; Demain, Arnold L.; Madia, Ashwin

1985-09-10

A method of saccharifying cellulose by incubation with the cellulase of Clostridium thermocellum in a broth containing an efficacious amount of a reducing agent. Other incubation parameters which may be advantageously controlled to stimulate saccharification include the concentration of alkaline earth salts, pH, temperature, and duration. By the method of the invention, even native crystalline cellulose such as that found in cotton may be completely saccharified.

Evaluation of the Rapid Polymyxin NP Test for Polymyxin B Resistance Detection Using Enterobacter cloacae and Enterobacter aerogenes Isolates.

PubMed

Simar, Shelby; Sibley, Diane; Ashcraft, Deborah; Pankey, George

2017-10-01

Polymyxin resistance is an increasing problem worldwide. Currently, determining susceptibility to polymyxins is problematic and lengthy. Polymyxins diffuse poorly into agar, potentially giving inaccurate disk diffusion and Etest results. A rapid screening test (2 h) for the detection of polymyxin resistance in Enterobacteriaceae , developed by P. Nordmann and L. Poirel (rapid polymyxin NP test) in 2016, detects glucose metabolization in the presence of polymyxin E (PE) and PB via pH-induced color change. The sensitivity and specificity were 99.3 and 95.4%, respectively, with results obtained in ≤2 h. Our goal was to evaluate this test using PB against larger numbers of Enterobacter A total of 143 nonduplicate Enterobacter isolates (102 E. cloacae complex, 41 E. aerogenes ) were tested, including 136 collected from Ochsner Health System patients from March to May 2016 and 7 previously determined PB-resistant E. cloacae isolates from JMI Laboratories. MICs were determined via broth microdilution. For the rapid polymyxin NP test, a color change from orange to yellow is positive; a weak/no color change is deemed negative after 4 h. Of 143 Enterobacter isolates, 25 were determined to be PB resistant by broth microdilution (MIC > 2 μg/ml), including all 7 JMI isolates. Of these 25, 7 were positive by the rapid polymyxin NP test (included 3/7 JMI isolates). All 118 isolates determined to be PB susceptible by broth microdilution were NP test negative. The sensitivity and specificity for the rapid polymyxin NP test were 25 and 100%, respectively, compared to broth microdilution. Although the rapid polymyxin NP test is a much faster method (2 to 4 h) for polymyxin resistance determination compared to broth microdilution (16 to 20 h), our study indicates that it may be subject to limitations when testing Enterobacter . Copyright © 2017 American Society for Microbiology.

[Evaluation of methods for studying susceptibility to oxacillin and penicillin in 60 Staphylococcus lugdunensis isolates].

PubMed

Batista, Nínive; Fernández, M Paula; Lara, Magdalena; Laich, Federico; Méndez, Sebastián

2009-03-01

Staphylococcus lugdunensis is a coagulase-negative staphylococcus associated with a variety of clinical infections. In this paper we present the results of a comparative study using 4 methods to determine antimicrobial susceptibility to oxacillin and penicillin in 60 S. lugdunensis isolates. We studied 60 S. lugdunensis isolates obtained from clinical specimens sent to our laboratory over an 8-year period. All isolates were free coagulase-negative and DNase-negative, and biochemically identified by API ID 32 STAPH (bioMérieux). Presence of mecA and ss-lactamase production were studied in all cases. Antimicrobial susceptibility was determined by the Vitek 2 System (bioMérieux) and broth microdilution (Wider) (Soria Melguizo) for penicillin and oxacillin, and the E-test (AB Biodisk) and cefoxitin disk diffusion test (BD BBLTM) for oxacillin. All isolates lacked the mecA gene and were susceptible to oxacillin by broth microdilution, E-test, and cefoxitin disk diffusion test. Only two isolates were oxacillin-resistant by the Vitek 2 System. Twenty-four isolates (40%) were ss-lactamase-positive, 4 after induction. Susceptibility testing to penicillin determined that 48 isolates showed concordance between the results obtained by broth microdilution and Vitek 2, but 12 isolates (20%), showed divergent results. We detected no resistance to oxacillin in S. lugdunensis. All the methods evaluated were adequate for determining oxacillin resistance. The Vitek 2 System is useful for detecting penicillin resistance, but the ss-lactamase test should be applied to isolates with a MIC=0.25microg/ml to avoid the interpretation of false resistance to this antibiotic.

Quantification of Growth of Campylobacter and Extended Spectrum β-Lactamase Producing Bacteria Sheds Light on Black Box of Enrichment Procedures.

PubMed

Hazeleger, Wilma C; Jacobs-Reitsma, Wilma F; den Besten, Heidy M W

2016-01-01

Campylobacter is well recognized as the leading cause of bacterial foodborne diarrheal disease worldwide, and is routinely found in meat originating from poultry, sheep, pigs, and cattle. Effective monitoring of Campylobacter contamination is dependent on the availability of reliable detection methods. The method of the International Organization for Standardization for the detection of Campylobacter spp. in food (ISO 10272-1:2006) recommends the use of Bolton broth (BB) as selective enrichment medium, including a pre-enrichment step of 4-6 h at 37°C to revive sublethally damaged cells prior to incubation for 2 days at 41.5°C. Recently the presence of abundantly growing extended spectrum β-lactamase producing Enterobacteriaceae (ESBL bacteria) has become one of the most important factors that interfere with the isolation of Campylobacter, resulting in false-negative detection. However, detailed growth dynamics of Campylobacter and its competitors remain unclear, where these would provide a solid base for further improvement of the enrichment procedure for Campylobacter. Other enrichment broths, such as Preston broth (PB) and BB plus clavulanic acid (BBc) have been suggested to inhibit competitive flora. Therefore, these different broths were used as enrichments to measure the growth kinetics of several strains of Campylobacter jejuni and ESBL bacteria separately, in co-culture and of strains in chicken samples. The maximum cell numbers and often the growth rates of Campylobacter in mixed culture with ESBL bacteria were significantly lower than in single cultures, indicating severe suppression of Campylobacter by ESBL bacteria, also in naturally contaminated samples. PB and BBc successfully diminished ESBL bacteria and might therefore be a better choice as enrichment medium in possibly ESBL-bacteria contaminated samples. The efficacy of a pre-enrichment step in the BB ISO-procedure was not supported for cold-stressed and non-stressed cells. Therefore, omission of this step (4-6 h at 37°C) might be advised to obtain a less troublesome protocol.

Doing More with Less? Toward Increasing the Resolution of Protistan Grazing-rate Measurements.

NASA Astrophysics Data System (ADS)

Morison, F.; Menden-Deuer, S.

2016-02-01

The dilution method is the standard protocol to quantify phytoplankton grazing-mortality rates and has been key in developing an understanding of protistan grazing impact on ocean primary production. Although the method's extensive use has facilitated the acquisition of a global dataset, its laborious application hinders the sampling resolution needed to fill knowledge gaps remaining at the geographical, seasonal, and vertical scales, and of the effects of climate-related factors influencing grazing magnitude. Here we present a rigorous assessment of an abbreviated method known as the 2-point. We analyzed unpublished results from 77 dilution experiments performed using a series of up to 5 dilutions under a wide range of chlorophyll concentrations and temperatures. We quantified the difference between estimates of both phytoplankton growth and grazing-mortality obtained based on the full dilution series and those obtained when the number of dilutions was reduced to 2. We considered the effect of non-linearity and chlorophyll concentration, and generated quantified estimates of trade-offs when choosing the fraction of seawater in the diluted treatment. Ultimately, we provide an assessment of the reliability of the 2-point method and recommendations on how to apply it.

Quality, antioxidative ability, and cell proliferation-enhancing activity of fermented black soybean broths with various supplemental culture medium.

PubMed

Lin, Chih-Chien; Wu, Pey-Shiuan; Liang, David Woei-Ming; Kwan, Chang-Chin; Chen, Yi-Shyan

2012-01-01

The fermented soybean-based foods have played an important role in traditional diets around the world for many centuries, and Bacillus subtilis is typically used in the fermentation of soybean-based foods. The fermentation process may improve not only the flavor but also the nutritional value of food, and substances produced in this fermented broth were affected by many factors including culture medium and the selected soybeans. In this study, we use 3 potential culture mediums in the fermentation of black soybean and the fermented black soybean broths were used for the examination of amino acid composition, total phenolics content, flavonoids and anthocyanins contents, the antioxidant properties, and cytotoxicity. Our results indicated that the fermented black soybean broth, fermentation III, have the most abundant essential amino acid (79.77 mg/g), phenolics (19.33 mg/g), flavonoids (46.01 mg/g), and anthocyanins (1.06 mg/g). Besides, all of the fermented black soybean broths exhibited the significant antioxidative abilities with 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effect, reducing power and ferrous ion chelating effect. In addition, the fermented black soybean broths demonstrated the cell proliferation-enhancing activity in Detroit 551 cells. The cells were augmented up to the maximum value of 183.6% (compared with control) at 10 mg/mL of the fermentation I. Therefore, the different supplemental culture medium fermented black soybean broths may be used as a functional ingredient in the products of nutritional drinks and health foods. The present study illustrated the potential of various supplemental culture medium fermented black soybean broths in the application of functional ingredient for nutritional drinks and health foods. © 2011 Institute of Food Technologists®

Validation of Modifications to the ANSR(®) Listeria Method for Improved Ease of Use and Performance.

PubMed

Caballero, Oscar; Alles, Susan; Le, Quynh-Nhi; Gray, R Lucas; Hosking, Edan; Pinkava, Lisa; Norton, Paul; Tolan, Jerry; Mozola, Mark; Rice, Jennifer; Chen, Yi; Odumeru, Joseph; Ryser, Elliot

2016-01-01

A study was conducted to validate minor reagent formulation, enrichment, and procedural changes to the ANSR(®) Listeria method, Performance-Tested Method(SM) 101202. In order to improve ease of use and diminish risk of amplicon contamination, the lyophilized reagent components were reformulated for increased solubility, thus eliminating the need to mix by pipetting. In the alternative procedure, an aliquot of the lysate is added to lyophilized ANSR reagents, immediately capped, and briefly mixed by vortexing. When three foods (hot dogs, Mexican-style cheese, and cantaloupe) and sponge samples taken from a stainless steel surface were tested, significant differences in performance between the ANSR and U.S. Food and Drug Administration Bacteriological Analytical Manual or U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook reference culture procedures were seen with hot dogs and Mexican-style cheese after 16 h enrichment, with the reference methods producing more positive results. After 24 h enrichment, however, there were no significant differences in method performance for any of the four matrixes tested. Robustness testing was also conducted, with variations to lysis buffer volume, lysis time, and sample volume having no demonstrable effect on assay results. Accelerated stability testing was carried out over a 10-week period and showed no diminishment in assay performance. A second phase of the study examined performance of the ANSR assay following enrichment in a new medium, LESS Plus broth, designed for use with all food and environmental sample types. With the alternative LESS Plus broth, there were no significant differences in performance between the ANSR method and the reference culture procedures for any of the matrixes tested after either 16 or 24 h enrichment, although 24 h enrichment is recommended for hot dogs due to higher sensitivity. Results of inclusivity and exclusivity testing using LESS Plus broth showed that the ANSR assay is highly specific, with 100% expected results for target and nontarget bacteria.

Methods and apparatuses for deoxygenating biomass-derived pyrolysis oil

DOEpatents

Baird, Lance Awender; Brandvold, Timothy A.

2015-10-20

Embodiments of methods and apparatuses for deoxygenating a biomass-derived pyrolysis oil are provided. In one example, a method comprises the steps of separating a low-oxygen biomass-derived pyrolysis oil effluent into a low-oxygen-pyoil organic phase stream and an aqueous phase stream. Phenolic compounds are removed from the aqueous phase stream to form a phenolic-rich diluent recycle stream. A biomass-derived pyrolysis oil stream is diluted and heated with the phenolic-rich diluent recycle stream to form a heated diluted pyoil feed stream. The heated diluted pyoil feed stream is contacted with a deoxygenating catalyst in the presence of hydrogen to deoxygenate the heated diluted pyoil feed stream.

Assessment of tolerance induction by Origanum vulgare L. essential oil or carvacrol in Pseudomonas aeruginosa cultivated in a meat-based broth and in a meat model.

PubMed

da Silva Luz, Isabelle; Gomes-Neto, Nelson Justino; Magnani, Marciane; de Souza, Evandro Leite

2015-12-01

This study assessed the efficacy of Origanum vulgare L. essential oil (OVEO) and carvacrol in inhibiting the growth of Pseudomonas aeruginosa ATCC 9027, as well as the development of direct tolerance and cross-tolerance when this bacterium was challenged with sublethal amounts of these substances in a meat-based broth and in a meat model. OVEO and carvacrol at their minimum inhibitory concentrations (MICs), 1/2 MIC and 1/4 MIC decreased the viable cell counts of P. aeruginosa in meat-based broth. Direct tolerance or cross-tolerance was not induced after exposure of the assayed bacterial strain to sublethal amounts of OVEO or carvacrol in meat-based broth and in an artificially contaminated ground beef. Bacterial cells progressively subcultured in meat-based broth with increasing amounts of the tested substances survived up to the MIC of OVEO and to 1/2 MIC of carvacrol. The results reveal a lack of induction of tolerance in P. aeruginosa by exposure to OVEO or carvacrol in meat-based broth and in a meat model. © The Author(s) 2014.

In Vitro Activity of Posaconazole against Talaromyces marneffei by Broth Microdilution and Etest Methods and Comparison to Itraconazole, Voriconazole, and Anidulafungin

PubMed Central

Lam, Clare S. K.; Ngan, Antonio H. Y.; Wu, Alan K. L.; Tsang, Dominic N. C.; Tse, Cindy W. S.; Que, Tak-Lun; Tang, Bone S. F.

2016-01-01

ABSTRACT We determined the susceptibilities of 57 Talaromyces marneffei strains to anidulafungin, itraconazole, voriconazole, and posaconazole with MICs of 2 to 8, 0.002 to 0.004, 0.016 to 0.063, and 0.001 to 0.002 μg/ml by broth microdilution and >32, ≤0.002 to 0.008, ≤0.002 to 0.008, and ≤0.002 μg/ml by Etest, respectively, at yeast phase; MICs at mycelial phase for anidulafungin and posaconazole were 1 to 2 and 0.004 to 0.063 μg/ml, respectively. The results suggest promising activities of posaconazole. Etest can be used for testing of azoles against T. marneffei. PMID:28031205

New Eudesmane-Type Sesquiterpenoids from the Mangrove-Derived Endophytic Fungus Penicillium sp. J-54

PubMed Central

Qiu, Liuming; Wang, Pei; Liao, Ge; Zeng, Yanbo; Cai, Caihong; Kong, Fandong; Guo, Zhikai; Proksch, Peter; Dai, Haofu; Mei, Wenli

2018-01-01

Four new eudesmane-type sesquiterpenoids, penicieudesmol A–D (1–4), were isolated from the fermentation broth of the mangrove-derived endophytic fungus Penicillium sp. J-54. Their structures were determined by spectroscopic methods, the in situ dimolybdenum CD method, and modified Mosher’s method. The bioassays results showed that 2 exhibited weak cytotoxicity against K-562 cells. PMID:29597304

Method of saccharifying cellulose

DOEpatents

Johnson, E.A.; Demain, A.L.; Madia, A.

1983-05-13

A method is disclosed of saccharifying cellulose by incubation with the cellulase of Clostridium thermocellum in a broth containing an efficacious amount of thiol reducing agent. Other incubation parameters which may be advantageously controlled to stimulate saccharification include the concentration of alkaline earth salts, pH, temperature, and duration. By the method of the invention, even native crystalline cellulose such as that found in cotton may be completely saccharified.

Immunological Relationship of Different Preparations of Coliform Enterotoxins

PubMed Central

Klipstein, Frederick A.; Engert, Richard F.

1978-01-01

Antisera raised in rabbits to ultrafiltrate toxin preparations containing either the heat-labile (LT) toxin form obtained from whole cell lysates or broth filtrates or the heat-stable (ST) toxin form prepared from broth filtrates from nontoxigenic and toxigenic strains of Escherichia coli and Klebsiella were examined for their ability to neutralize the secretory effect on water transport of these toxins in the rat jejunum as determined by the in vivo marker perfusion technique. Antisera to the heat-labile toxin derived from whole cell lysate preparations from nontoxigenic strains had no neutralizing effect. Antisera to both types of LT preparation from both toxigenic strains neutralized, with several exceptions, all of the homologous and heterologous LT toxins as well as a heat-labile toxin preparation derived from sequential ultrafiltration of cell-free whole cell lysates which had a defined molecular weight of between 30,000 and 100,000. These antisera also neutralized homologous and heterologous ST preparations obtained from broth filtrates, but they had no neutraliziṅg effect on low-molecular-weight, ST toxin material obtained during the sequential ultrafiltration of cell lysates. Antisera to ST prepared from broth filtrates had no neutralizing capacity against either LT or ST toxin preparations. These observations (i) indicate that the immunological relationship of E. coli and Klebsiella LT and ST toxins extends to antisera raised against LT prepared by several different methods, (ii) raise the possibility that, based on the response to antisera to LT, there may be several immunologically heterogeneous forms of low-molecular-weight ST toxin, and (c) confirm the lack of immunogenicity of ST. PMID:361578

The development of a practicable method for deepfreezing of boar spermatozoa.

PubMed

Larsson, K; Einarsson, S; Swensson, T

1977-03-01

The present study was made in order to develop the freezing method of Crabo & Einarsson (1971) into a practicable deep-freezing method for boar spermatozoa. Semen was concentrated before dilution and a dosewise thawing procedure for the pellet-frozen semen was utilized. Two fertility tests on altogther 68 gilts were performed. In the first trial the insemination doses contained 6x10(9) spermatozoa and the dilution rate before cooling was 3:2 with a total dilution before freezing of 3:7. In the second trial the insemination doses contained 4.5x10(9) spermatozoa, primary dilution was 3:3 and final dilution 3:7. The pregnancy rate in trial 1 was 53% and in trial 2 72%. Mean litter size in pregnant gilts was 6.5 in trial 1 and 9.7 in trial 2. The difference in ratio of foetuses to c.l. in pregnant gilts between the trials was highly significant. The different dilution procedures are discussed and the lower fertility of semen frozen in trial 1 is suggested to be due to a shortened fertile life of spermatozoa so treated. The freezing method utilized in trial 2 is considered to be practically acceptable and the results are concluded to be satisfactory. A detailed description of the method and the equipment utilized can be requested from the authors.

Production and distribution of dilute species in semiconducting materials

DOEpatents

James, Ralph B.; Camarda, Giuseppe; Bolotnikov, Aleksey E.; Hossain, Anwar; Yang, Ge; Kim, Kihyun

2016-09-06

Technologies are described effective to implement systems and methods of producing a material. The methods comprise receiving a tertiary semiconductor sample with a dilute species. The sample has two ends. The first end of the sample includes a first concentration of the dilute species lower than a second concentration of the dilute species in the second end of the sample. The method further comprises heating the sample in a chamber. The chamber has a first zone and a second zone. The first zone having a first temperature higher than a second temperature in the second zone. The sample is orientated such that the first end is in the first zone and the second end is in the second zone.

Screening fungicides for use in fish culture: Evaluation of the agar plug transfer, cellophane transfer, and agar dilution methods

USGS Publications Warehouse

Bailey, Tom A.

1983-01-01

The reliability, reproducibility, and usefulness of three screening methods -- the cellophane transfer, the agar plug transfer, and the agar dilution -- to screen aquatic fungicides were evaluated. Achlya flagellata and Saprolegnia hypogyna were exposed to 1, 10, and 100 mg/L of malachite green to test each method. The cellophane transfer and agar plug transfer techniques had similar reliability and reproducibility in rating fungicidal activity, and were both superior to the agar dilution technique. The agar plug transfer and agar dilution techniques adequately projected in vivo activity of malachite green, but the cellophane transfer technique overestimated its activity. Overall, the agar plug transfer technique most accurately rated the activity of malachite green and was the easiest test to perform. It therefore appears to be the method of choice for testing aquatic fungicides.

Multi-laboratory survey of qPCR enterococci analysis method performance

EPA Pesticide Factsheets

Quantitative polymerase chain reaction (qPCR) has become a frequently used technique for quantifying enterococci in recreational surface waters, but there are several methodological options. Here we evaluated how three method permutations, type of mastermix, sample extract dilution and use of controls in results calculation, affect method reliability among multiple laboratories with respect to sample interference. Multiple samples from each of 22 sites representing an array of habitat types were analyzed using EPA Method 1611 and 1609 reagents with full strength and five-fold diluted extracts. The presence of interference was assessed three ways: using sample processing and PCR amplifications controls; consistency of results across extract dilutions; and relative recovery of target genes from spiked enterococci in water sample compared to control matrices with acceptable recovery defined as 50 to 200%. Method 1609, which is based on an environmental mastermix, was found to be superior to Method 1611, which is based on a universal mastermix. Method 1611 had over a 40% control assay failure rate with undiluted extracts and a 6% failure rate with diluted extracts. Method 1609 failed in only 11% and 3% of undiluted and diluted extracts analyses. Use of sample processing control assay results in the delta-delta Ct method for calculating relative target gene recoveries increased the number of acceptable recovery results. Delta-delta tended to bias recoveries fr

Transcription analysis of stx1, marA, and eaeA genes in Escherichia coli O157:H7 treated with sodium benzoate.

PubMed

Critzer, Faith J; Dsouza, Doris H; Golden, David A

2008-07-01

Expression of the multiple antibiotic resistance (mar) operon causes increased antimicrobial resistance in bacterial pathogens. The activator of this operon, MarA, can alter expression of >60 genes in Escherichia coli K-12. However, data on the expression of virulence and resistance genes when foodborne pathogens are exposed to antimicrobial agents are lacking. This study was conducted to determine transcription of marA (mar activator), stx1 (Shiga toxin 1), and eaeA (intimin) genes of E. coli O157:H7 EDL933 as affected by sodium benzoate. E. coli O157:H7 was grown in Luria-Bertani broth containing 0 (control) and 1% sodium benzoate at 37 degrees C for 24 h, and total RNA was extracted. Primers were designed for hemX (209 bp; housekeeping gene), marA (261 bp), and eaeA (223 bp) genes; previously reported primers were used for stx1. Tenfold dilutions of RNA were used in a real-time one-step reverse transcriptase PCR to determine transcription levels. All experiments were conducted in triplicate, and product detection was validated by gel electrophoresis. For marA and stx1, real-time one-step reverse transcriptase PCR products were detected at a 1-log-greater dilution in sodium benzoate-treated cells than in control cells, although cell numbers for each were similar (7.28 and 7.57 log CFU/ml, respectively). This indicates a greater (albeit slight) level of their transcription in treated cells than in control cells. No difference in expression of eaeA was observed. HemX is a putative uroporphyrinogen III methylase. The hemX gene was expressed at the same level in control and treated cells, validating hemX as an appropriate housekeeping marker. These data indicate that stx1 and marA genes could play a role in pathogen virulence and survival when treated with sodium benzoate, whereas eaeA expression is not altered. Understanding adaptations of E. coli O157:H7 during antimicrobial exposure is essential to better understand and implement methods to inhibit or control survival of this pathogen in foods.

A colorimetric broth microdilution method for assessment of Helicobacter pylori sensitivity to antimicrobial agents.

PubMed

Knezevic, Petar; Aleksic Sabo, Verica; Simin, Natasa; Lesjak, Marija; Mimica-Dukic, Neda

2018-04-15

Helicobacter pylori is a major infective etiological agent of the upper gastrointestinal tract diseases. The bacterium exhibits resistance to various conventional antibiotics, being usually challenging for eradication. Since there is an urge to consider alternative therapeutic strategies, the aim of the study was to examine selected essential oils of plants belonging to families Cupressaceae (Juniperus communis) and Lamiaceae (Hyssopus officinalis, Salvia officinalis, Melissa officinalis, Lavandula angustifolia, Ocimum basilicum and Thymus serpyllum) against H. pylori, using an improved microdilution broth method. The oils were examined in concentration range from 0.03 to 4 μL/mL. The method comprises Brain-heart infusion broth supplemented with yeast extract, horse serum and IsoVitaleX. After 3 day incubation, an equal volume of double strengthen Christensen's urea was added into each well and incubated for additional 4 h. In wells with present H. pylori, the medium changed color from yellow to purple, allowing MIC determination even without a microtitre plate reader. The microtitre format method is convenient as it is less expensive, easier to perform and requires less amount of an anti-H. pylori agent. The improved method enhances specificity to H. pylori, as fast urease activity is almost an exclusive property of this bacterium. The application of the second step incubation with Christensen's urea decreases the possibility of false positive/negative results due to contaminant growth or commonly poor H. pylori growth. Among the examined oils, J. communis, H. officinalis and O. basilicum were not active with the highest applied concentrations, while the most active was T. serpyllum, with MIC 2.0-4.0 μL/mL. This is the first report on essential oils activity of T. serpyllum and H. officinalis against H. pylori. Copyright © 2018 Elsevier B.V. All rights reserved.

Novel method for on-road emission factor measurements using a plume capture trailer.

PubMed

Morawska, L; Ristovski, Z D; Johnson, G R; Jayaratne, E R; Mengersen, K

2007-01-15

The method outlined provides for emission factor measurements to be made for unmodified vehicles driving under real world conditions at minimal cost. The method consists of a plume capture trailer towed behind a test vehicle. The trailer collects a sample of the naturally diluted plume in a 200 L conductive bag and this is delivered immediately to a mobile laboratory for subsequent analysis of particulate and gaseous emissions. The method offers low test turnaround times with the potential to complete much larger numbers of emission factor measurements than have been possible using dynamometer testing. Samples can be collected at distances up to 3 m from the exhaust pipe allowing investigation of early dilution processes. Particle size distribution measurements, as well as particle number and mass emission factor measurements, based on naturally diluted plumes are presented. A dilution profile relating the plume dilution ratio to distance from the vehicle tail pipe for a diesel passenger vehicle is also presented. Such profiles are an essential input for new mechanistic roadway air quality models.

Effect of certain natural products and organic solvents on quorum sensing in Chromobacterium violaceum.

PubMed

Chaudhari, Vimla; Gosai, Haren; Raval, Shreya; Kothari, Vijay

2014-09-01

To investigate the effect of seed extracts of Pongamia pinnata, Pyrus pyrifolia, and Manilkara hexandra, bacterial pigment prodigiosin, and three organic solvents (ethanol, methanol, and dimethylsulfoxide), on quorum sensing (QS) in Chromobacterium violaceum (C. violaceum). C. violaceum was challenged with plant extracts prepared by microwave assisted extraction method, prodigiosin, and organic solvents. Effect of these test substances on C. violaceum growth, and quorum sensing regulated pigment (violacein) production was studied by broth dilution assay. High performance liquid chromatography was also applied to generate chromatographic fingerprint of the active extracts. Effect of sub-minimum inhibitory concentration level of the antibiotic streptomycin on quorum sensing regulated pigment production was also studied. Pongamia pinnata seed extracts and prodigiosin were found to possess anti-QS, and Manilkara hexandra and Pyrus pyrifolia seed extracts to possess QS-enhancing effect in C. violaceum. Dimethylsulfoxide was found to enhance violacein production, whereas ethanol and methanol reduced violacein production in C. violaceum. Streptomycin at sub-minimum inhibitory concentration level was able to significantly arrest QS-regulated pigment production in C. violaceum and Serratia marcescens. Prodigiosin and the seed extracts used in this study could affect quorum sensing in C. violaceum to a notable extent. Results of this study also emphasize the importance of inclusion of appropriate solvent controls (negative controls) in bioassays designed for screening of antimicrobial and/or anti-QS compounds. Antipathogenic potential of low concentrations of streptomycin was also demonstrated. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Prevalence, outcome and risk factor associated with vancomycin-resistant Enterococcus faecalis and Enterococcus faecium at a Tertiary Care Hospital in Northern India.

PubMed

Tripathi, A; Shukla, S K; Singh, A; Prasad, K N

2016-01-01

To determine the prevalence, genotype, risk factors and mortality in patients having vancomycin-resistant Enterococcus faecalis (VR E. faecalis) and Enterococcus faecium (VR E. faecium) infection or colonisation. A total of 1488 clinical isolates of E. faecalis and E. faecium were tested for vancomycin resistance by phenotypic (disk diffusion, E-test and broth micro-dilution test) and genotypic polymerase chain reaction methods. Records of all 1488 patients who had E. faecalis or E. faecium infection or colonisation were reviewed for the identification of host, hospital and medication related risk factors associated with VR E. faecalis and VR E. faecium. Of 1488 isolates, 118 (7.9%) were vancomycin-resistant and their distributions were as follows: E. faecalis=72 (61%) and E. faecium=46 (39%). All 118 vancomycin-resistant isolates were vanA genotype (minimum inhibitory concentration [MIC] to vancomycin ≥64 μg/ml and MIC to teicoplanin≥32 μg/ml) and none of the isolates was vanB genotype. Multivariate logistic regression analysis identified ventilator support and hospital stay for ≥48 h as independent risk factors associated with VR E. faecalis and VR E. faecium infection or colonisation. Hospital stay≥48 h was the only independent risk factor for mortality in patients infected with vancomycin-resistant enterococci. Strategies to limit the nosocomial infection especially in patients on ventilator support can reduce VRE incidence and related mortality.

Endophytic fungi associated with Sudanese medicinal plants show cytotoxic and antibiotic potential.

PubMed

Khiralla, Afra; Mohamed, Ietidal E; Tzanova, Tzvetomira; Schohn, Hervé; Slezack-Deschaumes, Sophie; Hehn, Alain; André, Philippe; Carre, Gaëlle; Spina, Rosella; Lobstein, Annelise; Yagi, Sakina; Laurain-Mattar, Dominique

2016-06-01

In this study, we isolated 15 endophytic fungi from five Sudanese medicinal plants. Each fungal endophytic strain was identified by sequencing of internal transcribed spacer (ITS) regions of rDNA. Ethyl acetate extracts were prepared from each endophyte cultivated in vitro and tested for their respective antibacterial activities and antiproliferative activities against human cancer cells. Antibacterial screening was carried out against two bacterial strains: Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus, by the broth dilution method. Cell viability was evaluated by the MTT procedure after exposure of MCF7 breast cancer cells and HT29 or HCT116 human colon adenocarcinoma cells to each endophytic extract. Of interest, Byssochlamys spectabilis isolated from Euphorbia prostata showed cytotoxicity (IC50 = 1.51 ± 0.2 μg mL(-1)) against MCF7 cells, but had a low effect against HT29 or HCT116 cells (IC50 > 20 μg mL(-1)). Cladosporium cladosporioides 2, isolated from Vernonia amygdalina leaves, showed antiproliferative activities against MCF7 cells (IC50 = 10.5 ± 1.5 μg mL(-1)) only. On the other hand, B. spectabilis and Alternaria sp. extract had antibacterial activities against the S. aureus strain. The findings of this work revealed that endophytic fungi associated with medicinal plants from Sudan could be considered as an attractive source of new therapeutic compounds. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Phyto-assisted synthesis of bio-functionalised silver nanoparticles and their potential anti-oxidant, anti-microbial and wound healing activities.

PubMed

Mohanta, Yugal Kishore; Biswas, Kunal; Panda, Sujogya Kumar; Bandyopadhyay, Jaya; De, Debashis; Jayabalan, Rasu; Bastia, Akshaya Kumar; Mohanta, Tapan Kumar

2017-12-01

Bio- synthesis of silver nanoparticles (AgNPs) was made by using the aqueous leaf extract of Ardisia solanacea. Rapid formation of AgNPs was observed from silver nitrate upon treatment with the aqueous extract of A. solanacea leaf. The formation and stability of the AgNPs in the colloidal solution were monitored by UV-visible spectrophotometer. The mean particle diameter of AgNPs was calculated from the DLS with an average size ∼4 nm and ∼65 nm. ATR-FTIR spectroscopy confirmed the presence of alcohols, aldehydes, flavonoids, phenols and nitro compounds in the leaf which act as the stabilizing agent. Antimicrobial activity of the synthesized AgNPs was performed using agar well diffusion and broth dilution method against the Gram-positive and Gram-negative bacteria. Further, robust anti-oxidative potential was evaluated by DPPH assay. The highest antimicrobial activity of synthesized AgNPs was found against Pseudomonas aeruginosa (28.2 ± 0.52 mm) whereas moderate activity was found against Bacillus subtilis (16.1 ± 0.76), Candida kruseii (13.0 ± 1.0), and Trichophyton mentagrophytes (12.6 ± 1.52). Moreover, the potential wound healing activity was observed against the BJ-5Ta normal fibroblast cell line. Current research revealed that A. solanacea was found to be a suitable source for the green synthesis of silver nanoparticles.

Evaluation of VIDAS Salmonella (SLM) easy Salmonella method for the detection of Salmonella in a variety of foods: collaborative study.

PubMed

Crowley, Erin; Bird, Patrick; Fisher, Kiel; Goetz, Katherine; Benzinger, M Joseph; Agin, James; Goins, David; Johnson, Ronald L

2011-01-01

The VIDAS Salmonella (SLM) Easy Salmonella method is a specific enzyme-linked fluorescent immunoassay performed in the automated VIDAS instrument. The VIDAS Easy Salmonella method is a simple 2-step enrichment procedure, using pre-enrichment followed by selective enrichment in a newly formulated broth, SX2 broth. This new method was compared in a multilaboratory collaborative study to the U.S. Food and Drug Administration's Bacteriological Analytical Manual, Chapter 5 method for five food matrixes (liquid egg, vanilla ice cream, spinach, raw shrimp, and peanut butter) and the U.S. Department of Agriculture's Microbiology Laboratory Guidebook 4.04 method for deli turkey. Each food type was artificially contaminated with Salmonella at three inoculation levels. A total of 15 laboratories representing government, academia, and industry, throughout the United States, participated. In this study, 1583 samples were analyzed, of which 792 were paired replicates and 791 were unpaired replicates. Of the 792 paired replicates, 285 were positive by both the VIDAS and reference methods. Of the 791 unpaired replicates, 341 were positive by the VIDAS method and 325 were positive by the cultural reference method. A Chi-square analysis of each of the six food types was performed at the three inoculation levels tested. For all foods evaluated, the VIDAS Easy SLM method demonstrated results comparable to those of the reference methods for the detection of Salmonella.

Significant decrease of broth viscosity and glucose consumption in erythromycin fermentation by dynamic regulation of ammonium sulfate and phosphate.

PubMed

Chen, Yong; Wang, Zejian; Chu, Ju; Zhuang, Yingping; Zhang, Siliang; Yu, Xiaoguang

2013-04-01

In this study, the effects of nitrogen sources on broth viscosity and glucose consumption in erythromycin fermentation were investigated. By controlling ammonium sulfate concentration, broth viscosity and glucose consumption were decreased by 18.2% and 61.6%, respectively, whereas erythromycin biosynthesis was little affected. Furthermore, erythromycin A production was increased by 8.7% still with characteristics of low broth viscosity and glucose consumption through the rational regulations of phosphate salt, soybean meal and ammonium sulfate. It was found that ammonium sulfate could effectively control proteinase activity, which was correlated with the utilization of soybean meal as well as cell growth. The pollets formation contributed much to the decrease of broth viscosity. The accumulation of extracellular propionate and succinate under the new regulation strategy indicated that higher propanol consumption might increase the concentration of methylmalonyl-CoA and propionyl-CoA and thus could increase the flux leading to erythromycin A. Copyright © 2013 Elsevier Ltd. All rights reserved.

Use Carum copticum essential oil for controlling the Listeria monocytogenes growth in fish model system

PubMed Central

Rabiey, Soghra; Hosseini, Hedayat; Rezaei, Masoud

2014-01-01

This study was conducted to evaluate the antibacterial effect of Carum copticum essential oil (Ajowan EO) against Listeria monocytogenes in fish model system. Ajowan EO chemical composition was determined by gas chromatography/mass spectral analysis and the highest concentration of Carum copticum essential oil without any significant changes on sensory properties of kutum fish (Rutilus frisii kutum) was assigned. Then the inhibitory effect of Ajowan EO at different concentrations in presence of salt and smoke component was tested on L. monocytogenes growth in fish peptone broth (FPB), kutum broth and cold smoked kutum broth at 4 °C for 12 days. Ajowan EO completely decreased the number of L. monocytogenes in FPB after 12 days of storage, however, antimicrobial effect of EO significantly reduced in kutum and cold smoked kutum broth. Addition of 4% NaCl and smoke component improved the anti-listerial activity of Ajowan EO in all fish model broths. PMID:24948918

A new versatile microarray-based method for high throughput screening of carbohydrate-active enzymes.

PubMed

Vidal-Melgosa, Silvia; Pedersen, Henriette L; Schückel, Julia; Arnal, Grégory; Dumon, Claire; Amby, Daniel B; Monrad, Rune Nygaard; Westereng, Bjørge; Willats, William G T

2015-04-03

Carbohydrate-active enzymes have multiple biological roles and industrial applications. Advances in genome and transcriptome sequencing together with associated bioinformatics tools have identified vast numbers of putative carbohydrate-degrading and -modifying enzymes including glycoside hydrolases and lytic polysaccharide monooxygenases. However, there is a paucity of methods for rapidly screening the activities of these enzymes. By combining the multiplexing capacity of carbohydrate microarrays with the specificity of molecular probes, we have developed a sensitive, high throughput, and versatile semiquantitative enzyme screening technique that requires low amounts of enzyme and substrate. The method can be used to assess the activities of single enzymes, enzyme mixtures, and crude culture broths against single substrates, substrate mixtures, and biomass samples. Moreover, we show that the technique can be used to analyze both endo-acting and exo-acting glycoside hydrolases, polysaccharide lyases, carbohydrate esterases, and lytic polysaccharide monooxygenases. We demonstrate the potential of the technique by identifying the substrate specificities of purified uncharacterized enzymes and by screening enzyme activities from fungal culture broths. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Synthesis and formation mechanism of pinnoite in sulfated-type boron concentrated brine by dilution method

NASA Astrophysics Data System (ADS)

Peng, Jiaoyu; Bian, Shaoju; Lin, Feng; Wang, Liping; Dong, Yaping; Li, Wu

2017-10-01

The synthesis of pinnoite (MgB2O(OH)6) in boron-containing brine was established with a novel dilution method. Effects of temperature, precipitation time, boron concentration and mass dilution ratio on the formation of pinnoite were investigated. The products obtained were characterized by X-ray diffraction (XRD), Raman, thermogravimetric and differential scanning calorimeter (TG-DSC), and scanning electron microscopy. The transformation mechanism of pinnoite with different dilution ratios was assumed by studying the crystal growth of pinnoite. The results showed that pinnoite was synthesized above 60 °C in the diluted brine. There were two reaction steps - precipitation of amorphous solid and the formation of pinnoite crystals - during the whole reaction process of pinnoite when the dilution ratio is more than 1.0 at 80 °C. While in the 0.5 diluted brine, only one reaction step of pinnoite crystal formation was observed and its transformation mechanism was discussed based on dissociation of polyborates in brine. Besides, the origin of pinnoite mineral deposited on salt lake bottom was proposed.

Microbiological culture broth designed from food waste.

PubMed

Chalón, Miriam C; Terán, Victoria; Arena, Mario E; Oliszewki, Rubén; González, Silvia N

2013-01-30

The current trend of increasing air, water, and soil pollution is, in part, due to inadequate management of municipal solid waste (MSW). The relationship between public health and the collection, storage and improper disposal of solid waste has encouraged several studies and the results were attributed to the spread of over twenty human and animal diseases due to this interrelationship. The term "single cell protein" (SCP) refers to microbial biomass used as a dietary additive. It has high nutritional value because of its high content of vitamins, lipids, and proteins of biological quality (the presence of all essential amino acids) (Lal, 2005). The aim of this work was to design a culture media for microbiological assays and to produce SCP for animal feeding, using nutrients contained in organic waste. In order to compare the effectiveness of food waste (FW) and LAPTg media, different strains of Lactobacillus, Enterococcus, Staphylococcus, Shigella, Salmonella, Saccharomyces and Schizosaccharomyces were studied. In all cases, the growth obtained from FW and LAPTg culture media were not significantly different (p > 0.05). In addition, the growth of Saccharomyces cerevisiae was studied in order to produce SCP for animal feeding. Comparative experiments involving molasses broth, FW broth, and basal broth were carried out. The biomass yield calculated at 24 h from FW broth was 13% lower than from molasses broth. The FW broth provided a significantly lower biomass yield; however, it can be very useful in areas where molasses are not available. FW broth can be elaborated at low cost, in any populated region of the world because its ingredients are wastes generated by humans. It has great versatility, allowing the development of a wide variety of microorganisms, both Gram negative and Gram positive bacteria as well as yeasts. The production of safe protein additives, with high biological quality and low cost, is necessary due to the increasing global demand for food for humans and animals. Copyright © 2012 Elsevier Ltd. All rights reserved.

21 CFR 175.270 - Poly(vinyl fluoride) resins.

Code of Federal Regulations, 2014 CFR

2014-04-01

...(vinyl fluoride) basic resins have an intrinsic viscosity of not less than 0.75 deciliter per gram as determined by ASTM method D1243-79, “Standard Test Method for Dilute Solution Viscosity of Vinyl Chloride... (ASTM method D1243-79, “Standard Test Method for Dilute Solution Viscosity of Vinyl Chloride Polymers...

Evaluation of the in vitro antibacterial activity of the solvent fractions of the leaves of Rhamnus prinoides L'Herit (Rhamnaceae) against pathogenic bacteria.

PubMed

Molla, Yalew; Nedi, Teshome; Tadesse, Getachew; Alemayehu, Haile; Shibeshi, Workineh

2016-08-15

Medicinal plants play great roles in the treatment of various infectious diseases. Rhamnus prinoides is one of the medicinal plants used traditionally for treatment of bacterial diseases. The antibacterial activity of the crude extract of the plant had been shown by a previous study, but this study was undertaken to further the claimed medicinal use of the plant by screening its solvent fractions for the said activity so that it could serve as a basis for subsequent studies. The solvent fractions of the plant were obtained by successive soxhlet extraction with solvents of increasing polarity, with chloroform and methanol, followed by maceration of the marc of methanol fraction with water. The antibacterial activity of the solvent fractions was evaluated on seven bacterial species using agar well diffusion method at different concentrations (78 mg/well, 39 mg/well and 19.5 mg/well) in the presence of positive and negative controls. The minimum inhibitory concentration of the solvent fractions was determined by micro-broth dilution method using resazurin as indicator. Methanol and chloroform fractions revealed antibacterial activities against the growth of test bacterial strains with varying antibacterial spectrum and the susceptible bacterial species were Staphylococcus aureus, Streptococcus pyogen, Streptococcus pneumoniae and Salmonella typhi. The average minimum inhibitory concentration value of the methanol and chloroform fractions ranged from 8.13 mg/ml to 32.5 mg/ml and from 8.13 mg/ml to 16.25 mg/ml, respectively. The methanol and chloroform fractions demonstrated significant antibacterial activities against the growth of pathogenic bacteria but the aqueous fraction did not reveal antibacterial activity against any of the test bacteria.

Anti-mycobacterial screening of five Indian medicinal plants and partial purification of active extracts of Cassia sophera and Urtica dioica.

PubMed

Singh, Rambir; Hussain, Shariq; Verma, Rajesh; Sharma, Poonam

2013-05-13

To find out the anti-mycobacterial potential of Cassia sophera (C. sophera), Urtica dioica (U. dioica), Momordica dioica, Tribulus terrestris and Coccinia indica plants against multi-drug resistant (MDR) strain of Mycobacterium tuberculosis (M. tuberculosis). Plant materials were extracted successively with solvents of increasing polarity. Solvent extracts were screened for anti-mycobacterial activity against fast growing, non-pathogenic mycobacterium strain, Mycobacterium semegmatis, by disk diffusion method. The active extracts were tested against MDR and clinical isolates of M. tuberculosis by absolute concentration and proportion methods. The active extracts were subjected to bio-autoassay on TLC followed by silica column chromatography for isolation of potential drug leads. Hexane extract of U. dioica (HEUD) and methanol extract of C. sophera (MECS) produced inhibition zone of 20 mm in disc diffusion assay and MIC of 250 and 125 μ g/mL respectively in broth dilution assay against Mycobacterium semegmatis. Semipurified fraction F2 from MECS produced 86% inhibition against clinical isolate and 60% inhibition against MDR strain of M. tuberculosis. F18 from HEUD produced 81% inhibition against clinical isolate and 60% inhibition against MDR strain of M. tuberculosis. Phytochemical analysis indicated that anti-mycobacterial activity of MECS may be due to presence of alkaloids or flavonoids and that of HEUD due to terpenoids. C. sophera and U. dioica plant extracts exhibited promising anti-mycobacterial activity against MDR strain of M. tuberculosis. This is the first report of anti-mycobacterial activity form C. sophera. This study showed possibility of purifying novel anti-mycobacterial compound(s) from C. sophera and U. dioica. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Antimicrobial activity and chemical composition of the essential oils of Portuguese Foeniculum vulgare fruits.

PubMed

Mota, Ana S; Martins, M Rosário; Arantes, Sílvia; Lopes, Violeta R; Bettencourt, Eliseu; Pombal, Sofia; Gomes, Arlindo C; Silva, Lúcia A

2015-04-01

The aim of this study was to investigate the chemical composition and antimicrobial activity of essential oils obtained by hydrodistillation from fruits of six fennel accessions collected from wild populations occurring in the centre and south of Portugal. Composition of essential oils was established by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The obtained yields of the essential oils were found to vary greatly in the range of 1.1 to 2.9% (v/w) and the chemical composition varied with the region of collection. A total of 16 compounds were identified. The main compounds were fenchone (16.9 - 34.7%), estragole (2.5 - 66.0%) and trans-anethole (7.9 - 77.7%). The percentages of these three main compounds were used to determine the relationship between the different oil samples and to group them into four different chemotypes: anethole/fenchone; anethole; estragole and anethole/estragole. Antifungal activity of essential oils was evaluated against six food spoilage fungi: Aspergillus niger, A. japonicus, A. oryzae, Fusarium oxysporum, Rhizophus oryzae and R. stolonifer. Antibacterial activity was assessed against three Gram-positive strains: Enterococcus faecalis ATCC 29212, Staphylococcus epidermidis ATCC 12228 and S. aureus ATCC 28213; and against six Gram-negative strains: Escherichia coli ATCC 25922; Morganella morganii LFG 08; Proteus mirabilis LFG 04; Salmonella enteritidis LFG 05; S. entiritidis serovar typhimurium LFG 06 and Pseudomonas aeruginosa ATCC 27853 by the disc diffusion agar method; the minimal inhibitory concentration (MIC) was determined using the broth macro-dilution method. The MIC values varied from 62.5 (E. coli ATCC 25922) to 2000 µmL (P. aeruginosa ATCC 27853).

Chemical composition and antifungal activity of Carica papaya Linn. seed essential oil against Candida spp.

PubMed

He, X; Ma, Y; Yi, G; Wu, J; Zhou, L; Guo, H

2017-05-01

In recent years, the incidence of clinical yeast infections has increased dramatically. Due to the extensive use of broad-spectrum antifungal agents, there has been a notable increase in drug resistance among infections yeast species. As one of the most popular natural antimicrobial agents, essential oils (EOs) have attracted a lot of attention from the scientific community. The aim of this study was to analyse the chemical composition and examine the antifungal activity of the EO extracted from the seeds of Carica papaya Linn. The papaya seed EO was analysed by gas chromatography-mass spectrometry. The major constituent is benzyl isothiocyanate (99·36%). The filter paper disc diffusion method and broth dilution method were employed. The EO showed inhibitory effect against all the tested Candida strains including C. albicans, C. glabrata, C. krusei, C. parapsilosis and C. tropical with inhibition zone diameters in the range of 14·2-33·2 mm, the minimal inhibitory concentrations (MICs) in the range of 4·0-16·0 μg ml -1 and the minimum fungicidal concentrations (MFCs) in the range of 16·0-64·0 μg ml -1 . Here, we found that the papaya seed EO has promising anticandida activity and identify C. papaya L. as a potential natural source of antifungal agents. The chemical composition and antifungal activity of essential oil of Carica papaya seeds were studied. The oil of papaya seeds could inhibit the growth of Candida spp. for the first report. Carica Papaya may be recognized as a possible new source of natural antifungal agents. © 2017 The Society for Applied Microbiology.

Synthesis, molecular docking, antimycobacterial and antimicrobial evaluation of new pyrrolo[3,2-c]pyridine Mannich bases.

PubMed

Jose, Gilish; Suresha Kumara, Tholappanavara H; Sowmya, Haliwana B V; Sriram, Dharmarajan; Guru Row, Tayur N; Hosamani, Amar A; More, Sunil S; Janardhan, Bhavya; Harish, B G; Telkar, Sandeep; Ravikumar, Yalegara Siddappa

2017-05-05

In this report, we describe the synthesis and biological evaluation of a new series of pyrrolo[3,2-c]pyridine Mannich bases (7a-v). The Mannich bases were obtained in good yields by one-pot three component condensation of pyrrolo[3,2-c]pyridine scaffold (6a-c) with secondary amines and excess of formaldehyde solution in AcOH. The chemical structures of the compounds were characterized by 1 H NMR, 13 C NMR, LC/MS and elemental analysis. Single crystal X-ray diffraction has been recorded for compound 7k ([C 23 H 29 ClN 4 ] +2 , H 2 O). The in vitro antimicrobial activities of the compounds were evaluated against various bacterial and fungal strains using Agar diffusion method and Broth micro dilution method. Compounds 7e, 7f, 7r, 7t, and 7u were showed good Gram-positive antibacterial activity against S. aureus, B. flexus, C. sporogenes and S. mutans. Furthermore, in vitro antimycobacterial activity was evaluated against Mycobacterium tuberculosis H37Rv (ATCC 27294) using MABA. Compounds 7r, 7t, and 7u were showed good antitubercular activity against Mtb (MIC ≥6.25 μg/mL). Among the tested compounds, 1-((4-chloro-2-(cyclohexylmethyl)-1H-pyrrolo[3,2-c]pyridin-3-yl)methyl)piperidine-3-carboxamide (7t) was showed excellent antimycobacterial activity against Mtb (MIC <0.78 μg/mL) and low cytotoxicity against the HEK-293T cell line (SI >25). Molecular docking of the active compounds against glutamate racemase (MurI) and Mtb glutamine synthetase were explained the structure-activity observed in vitro. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Cytotoxic and antimicrobial activity of selected Cameroonian edible plants

PubMed Central

2013-01-01

Background In Cameroon, the use of edible plants is an integral part of dietary behavior. However, evidence of the antimicrobial as well as the cytotoxic effects of many of them has not been investigated. In the present study, aqueous and methanol extracts from barks, seeds, leaves and roots of three Cameroonian edible plants namely Garcina lucida, Fagara heitzii and Hymenocardia lyrata were evaluated for their cytotoxic and antimicrobial activities. Methods Antibacterial and antifungal activities were assessed by the broth micro-dilution method meanwhile the cytotoxicity was performed using sulphorhodamine B assay (SRB) against the human leukemia THP-1, the alveolar epithelial A549, prostate cancer PC-3, breast adenocarcinoma MCF-7 and cervical cancer HeLa cell lines. Results The minimum inhibitory concentration (MIC) values of the seven tested extracts ranged from 62.5 μg/ml to 1000 μg/ml. The methanol (MeOH) extract from the roots of H. lyrata showed the highest antibacterial activity against Gram-positive bacteria S. aureus and S. epidermitis. The best antifungal activity was obtained with the MeOH extract from the leaves of G. lucida against C. tropicalis (MIC value of 62.5 μg/ml). The in vitro antiproliferative activity revealed that, extract from the bark of F. heitzii and extract from H. lyrata roots had significant cytotoxic activity on THP-1 (IC50 8.4 μg/ml) and PC-3 (IC50 9.5 μg/ml) respectively. Conclusion Our findings suggest that Cameroonian spices herein studied could be potentially useful for the development of therapeutic agents against bacterial infections as well as for prostate and leukemia cancer. PMID:23565827

Antibacterial and leishmanicidal activity of Bolivian propolis.

PubMed

Nina, N; Lima, B; Feresin, G E; Giménez, A; Salamanca Capusiri, E; Schmeda-Hirschmann, G

2016-03-01

The antimicrobial activity of Bolivian propolis was assessed for the first time on a panel of bacteria and two endemic parasitic protozoa. Ten samples of Bolivian propolis and their main constituents were tested using the micro-broth dilution method against 11 bacterial pathogenic strains as well as against promastigotes of Leishmania amazonensis and L. braziliensis using the XTT-based colorimetric method. The methanolic extracts showed antibacterial effect ranging from inactive (MICs > 1000 μg ml(-1) ) to low (MICs 250-1000 μg ml(-1) ), moderate (62·5-125 μg ml(-1) ) and high antibacterial activity (MIC 31·2 μg ml(-1) ), according to the collection place and chemical composition. The most active samples towards Leishmania species were from Cochabamba and Tarija, with IC50 values of 12·1 and 7·8, 8·0 and 10·9 μg ml(-1) against L. amazonensis and Leishmania brasiliensis respectively. The results show that the best antibacterial and antiprotozoal effect was observed for some phenolic-rich propolis. Propolis is used in Bolivia as an antimicrobial agent. Bolivian propolis from the main production areas was assessed for antibacterial and leishmanicidal effect and the results were compared with the propolis chemical composition. The active antibacterial propolis samples were phenolic-rich while those containing mainly triterpenes were devoid of activity or weakly active. A similar picture was obtained for the effect on Leishmania, with better effect for the phenolic-rich samples. As propolis is used for the same purposes regardless of the production area and composition, our findings indicate the need for the standardization of this natural product as antimicrobial. © 2016 The Society for Applied Microbiology.

Effect of aqueous and alcoholic Stevia (Stevia rebaudiana) extracts against Streptococcus mutans and Lactobacillus acidophilus in comparison to chlorhexidine: An in vitro study

PubMed Central

Ajagannanavar, Sunil Lingaraj; Shamarao, Supreetha; Battur, Hemant; Tikare, Shreyas; Al-Kheraif, Abdulaziz Abdullah; Al Sayed, Mohammed Sayed Al Esawy

2014-01-01

Introduction: Stevia (S. rebaudiana) a herb which has medicinal value and was used in ancient times as a remedy for a great diversity of ailments and sweetener. Leaves of Stevia contain a high concentration of Stevioside and Rebaudioside which are supposed to be sweetening agents. Aim: To compare the efficacy of aqueous and alcoholic S. rebaudiana extract against Streptococcus mutans and Lactobacillus acidophilus in comparison to chlorhexidine. Materials and Methods: In the first part of the study, various concentrations of aqueous and ethanolic Stevia extract were prepared in the laboratory of Pharmacy College. It was then subjected to microbiological assay to determine its zone of inhibition using Agar disk diffusion test and minimum inhibitory concentration (MIC) using serial broth dilution method against Streptococcus mutans and Lactobacillus acidophilus. Chlorhexidine was used as a positive control. One way Analysis of Variance (ANOVA) test was used for multiple group comparisons followed by Tukey post hoc for group wise comparisons. Results: Minimum inhibitory concentration (MIC) of aqueous and ethnolic Stevia extract against Streptococcus mutans and Lactobacillus acidophilus were 25% and 12.5% respectively. Mean zone of inhibition of the aqueous and alcoholic Stevia extracts against Streptococcus mutans at 48 hours were 22.8 mm and 26.7 mm respectively. Mean zone of inhibition of the aqueous and alcoholic Stevia extracts against Lactobacillus acidophilus at 48 hours were 14.4 mm and 15.1 mm respectively. Mean zone of inhibition of the chlorhexidine against Streptococcus mutans and Lactobacillus acidophilus at 48 hours was 20.5 and 13.2 respectively. Conclusion: The inhibitory effect shown by alcoholic Stevia extract against Streptococcus mutans and Lactobacillus acidophilus was superior when compared with that of aqueous form and was inferior when compared with Chlorhexidine. PMID:25558451

First Survey of Metallo-β–Lactamase Producers in Clinical Isolates of Pseudomonas aeruginosa From a Referral Burn Center in Kurdistan Province

PubMed Central

Kalantar, Enayatollah; Torabi, Vahideh; Salimizand, Heiman; Soheili, Fariborz; Beiranvand, Soheila; Soltan Dallal, Mohammad Mehdi

2012-01-01

Background Treatment of infectious diseases is becoming more challenging with each passing year. This is especially true for infections caused by Pseudomonas aeruginosa, an opportunistic pathogen with the ability to rapidly develop resistance to multiple classes of antibiotics. Objectives This study was conducted to determine the prevalence of metallo-β-lactamase (MBL)–producing strains among multidrug-resistant P. aeruginosa strains isolated from burn patients. Materials and Methods The isolates were identified, tested for susceptibility to various antimicrobial agents, and screened for the presence of MβLs by using the double-disk synergy test. The minimal inhibitory concentration of imipenem was determined by microplate broth dilution method on Mueller-Hinton agar. To detect VIM, SIM, and GIM MBLs, the isolates were subjected to polymerase chain reaction. Results In this study, we identified 100 P. aeruginosa isolates from 176 clinical specimens obtained from burn patients. The isolates showed maximum resistance to ampicillin (100%), ceftazidime (94%), and ceftriaxone (89%). The CLSI-MBL phenotypic test showed that of the 100 P. aeruginosa isolates, 22 (22%) were positive for MBL production in the double-disk synergy test. Of the 22 MBL-positive P. aeruginosa isolates, 8 were resistant to imipenem. PCR analysis showed that 8 isolates were positive for blaVIM1. The other genes blaSIM1 and blaGIM1 were not detected. Conclusions The study results demonstrate the serious therapeutic threat of the spread of MBL producers among P. aeruginosa populations. Metallo-β-lactamases were detected in 22% of imipenem-resistant P. aeruginosa isolates. Early detection and infection-control practices are the best antimicrobial strategies for this organism; therefore, systematic surveillance to detect MBL producers is necessary. PMID:24624147

Characterization of anticancer, antimicrobial, antioxidant properties and chemical compositions of Peperomia pellucida leaf extract.

PubMed

Wei, Lee Seong; Wee, Wendy; Siong, Julius Yong Fu; Syamsumir, Desy Fitrya

2011-01-01

Peperomia pellucida leaf extract was characterized for its anticancer, antimicrobial, antioxidant activities, and chemical compositions. Anticancer activity of P. pellucida leaf extract was determined through Colorimetric MTT (tetrazolium) assay against human breast adenocarcinoma (MCF-7) cell line and the antimicrobial property of the plant extract was revealed by using two-fold broth micro-dilution method against 10 bacterial isolates. Antioxidant activity of the plant extract was then characterized using α, α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging method and the chemical compositions were screened and identified using gas chromatography-mass spectrometry (GC-MS). The results of present study indicated that P. pellucida leaf extract possessed anticancer activities with half maximal inhibitory concentration (IC(50)) of 10.4 ± 0.06 µg/ml. The minimum inhibitory concentration (MIC) values were ranged from 31.25 to 125 mg/l in which the plant extract was found to inhibit the growth of Edwardsiella tarda, Escherichia coli, Flavobacterium sp., Pseudomonas aeruginosa and Vibrio cholerae at 31.25 mg/l; Klebsiella sp., Aeromonas hydrophila and Vibrio alginolyticus at 62.5 mg/l; and it was able to control the growth of Salmonella sp. and Vibrio parahaemolyticus at 125 mg/l. At the concentration of 0.625 ppt, the plant extract was found to inhibit 30% of DPPH, free radical. Phytol (37.88%) was the major compound in the plant extract followed by 2-Naphthalenol, decahydro- (26.20%), Hexadecanoic acid, methyl ester (18.31%) and 9,12-Octadecadienoic acid (Z,Z)-, methyl ester (17.61%). Findings from this study indicated that methanol extract of P. pellucida leaf possessed vast potential as medicinal drug especially in breast cancer treatment.

Antibacterial activity of crude extracts of prasaprohyai formula and its components against pathogenic bacteria.

PubMed

Sattaponpan, Chisanucha; Kondo, Sumalee

2011-12-01

Prasaprohyai formula is a Thai Traditional Medicine which has been used for reducing feverish in child. Fever is a symptom resulting from various infections and diseases. The major cause of fever is bacterial and viral infections. The Prasaprohyai formula and its components potentially have biological activities including antipyretic and antimicrobial activities. It is in a hope to develop the formula and its components for an alternative medicine of infectious diseases. To study antibacterial activity of Prasaprohyai formula and its components against pathogenic bacteria. Prasaprohyai formula and its components were extracted by different methods, A: maceration with 95% ethanol followed by evaporation (ET), B: ET followed by freeze drying (EF) and C: water distillation (VO). All extracts were tested against clinical isolates from Thammasat University Hospital, Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922. Disk diffusion and broth dilution methods were performed. Crude extracts of ET had higher yield of extraction than other methods. The results showed that the crude extract from different methods of Syzygium aromaticum (Linn) Merr & Perry (Flower) was effective against all bacterial strains with the inhibition zone ranging from 9 to 19 mm. The VO extract of Prasaprohyai formula showed antibacterial activity against most of the pathogenic bacteria in the present study. The activity against Streptococcus pyogenes was found in the VO extract of some components. The ET extracts of Lepidium sativum Linn, Myristica fragrans Houtt (seed) and Myristica fragrans Houtt (aril) had no antibacterial activity against all microorganism. However the EF extracts of this formula and some components were able to mostly inhibit Gram positive bacteria. The results indicated that Prasaprohyai formula and its components were able to inhibit the growth of both Gram positive and Gram negative bacteria including multiresistant strains. The volatile oil extracts seemed to play an important role in antimicrobial activities. The development of Prasaprohyai formula for alternative medicine will be approached in future.

Assessing the Accuracy of the Tracer Dilution Method with Atmospheric Dispersion Modeling

NASA Astrophysics Data System (ADS)

Taylor, D.; Delkash, M.; Chow, F. K.; Imhoff, P. T.

2015-12-01

Landfill methane emissions are difficult to estimate due to limited observations and data uncertainty. The mobile tracer dilution method is a widely used and cost-effective approach for predicting landfill methane emissions. The method uses a tracer gas released on the surface of the landfill and measures the concentrations of both methane and the tracer gas downwind. Mobile measurements are conducted with a gas analyzer mounted on a vehicle to capture transects of both gas plumes. The idea behind the method is that if the measurements are performed far enough downwind, the methane plume from the large area source of the landfill and the tracer plume from a small number of point sources will be sufficiently well-mixed to behave similarly, and the ratio between the concentrations will be a good estimate of the ratio between the two emissions rates. The mobile tracer dilution method is sensitive to different factors of the setup such as placement of the tracer release locations and distance from the landfill to the downwind measurements, which have not been thoroughly examined. In this study, numerical modeling is used as an alternative to field measurements to study the sensitivity of the tracer dilution method and provide estimates of measurement accuracy. Using topography and wind conditions for an actual landfill, a landfill emissions rate is prescribed in the model and compared against the emissions rate predicted by application of the tracer dilution method. Two different methane emissions scenarios are simulated: homogeneous emissions over the entire surface of the landfill, and heterogeneous emissions with a hot spot containing 80% of the total emissions where the daily cover area is located. Numerical modeling of the tracer dilution method is a useful tool for evaluating the method without having the expense and labor commitment of multiple field campaigns. Factors tested include number of tracers, distance between tracers, distance from landfill to transect path, and location of tracers with respect to the hot spot. Results show that location of the tracers relative to the hot spot of highest landfill emissions makes the largest difference in accuracy of the tracer dilution method.

Particles size distribution in diluted magnetic fluids

NASA Astrophysics Data System (ADS)

Yerin, Constantine V.

2017-06-01

Changes in particles and aggregates size distribution in diluted kerosene based magnetic fluids is studied by dynamic light scattering method. It has been found that immediately after dilution in magnetic fluids the system of aggregates with sizes ranging from 100 to 250-1000 nm is formed. In 50-100 h after dilution large aggregates are peptized and in the sample stationary particles and aggregates size distribution is fixed.