Fermentative Biohydrogen Production with Enteric Bacteria Isolated from the Intestine of Wild Common Carp Dwelling in Tarim River Basin

The biological hydrogen generating from fermentation of low-cost lignocellulosic feedstocks by hydrogen-producing bacteria has attracted many attentions in recent years. In the present investigation, ten hydrogen-producing bacteria were newly isolated from the intestine of wild common carp (Cyprinus carpio L.), and identified belonging to the genera of Enterobacter and Klebsiella based on analysis of the 16S rDNA gene sequence and examination of the physiological and biochemical characteristics. All the isolates inherently owned the ability to metabolize xylose especially the cotton stalk hydrolysate for hydrogen production with hydrogen yield (HY) higher than 100 mL·L-1. In particular, two isolates, WL1306 and WL1305 obtained higher HY, hydrogen production rate (HPR), and hydrogen production potential (HPP) using cotton stalk hydrolysate as sugar substrate than the mixed sugar of glucose & xylose, which obtained the HY of 249.5 ± 29.0, 397.0 ± 36.7 mL·L-1, HPR of 10.4 ± 1.2, 16.5 ± 1.5 mL·L-1·h-1, HPP of 19.5 ± 2.3, 31.0 ± 2.8 mL·L-1·g-1sugar, separately. The generation of soluble metabolites, such as the lactate, formate, acetate, succinate and ethanol reflected the mixed acid fermentation properties of the hydrogen production pathway.

Development of an Enteric Bacterial Enrichment Broth and Its Performance for Isolation of Clinically Significant Bacterial Pathogens from Stool

Background: Early detection and accurate identification of foodborne pathogen outbreaks is an important public health function. Increased clinical adoption of multiplex PCR assays or culture independent diagnostic tests (CIDT) correlates to more stool specimens sent to public health laboratories (PHL) for characterization. Isolation and confirmation of enteric bacterial pathogens can prove difficult to consistently recover. The purpose of this study was to evaluate the performance of a broad-use laboratory developed enrichment broth for isolation of Campylobacter, Salmonella, Shigella, and Yersinia strains from stool specimens. Methods: The study compared differences in positivity rates among media and enrichment combinations at specific time points. Comparison of direct inoculation (DI), enrichment using a lab-developed Enteric Bacterial Enrichment (EBE) broth and gold-standard isolation methods were conducted to test current utility of this established practice with stool specimens heat injured and non-injured. Results: A total of 234 spiked stool samples, 175 non-injured and 59 heat injured, were tested with varying bacterial concentrations. For non-injured stools, direct inoculation performed better for Campylobacter and Yersinia than enrichment. Conversely, Salmonella and Shigella recovery and limit of detection increased with enrichment. Campylobacter had the highest percent recovery while Shigella being the lowest from direct plating at 6-hour and 24-hour enrichment periods. Among broths, EBE performed the best for Yersinia and similar to Selenite broth for Salmonella and Shigella. Generally, heat injured stool had a significantly lower percent of recovery than non-heat injured with a higher limit of detection across organisms. Conclusion: Our data suggest there is an only utility for targeted enrichment of CIDT positive Salmonella stool specimens. We highlight the difficulties of formulating an enrichment broth capable of supporting a variety of enteric pathogens with standardized incubation. Increasing demands on PHL infrastructure warrant further examination of enhancing organism isolation and cost analyses for CIDT positive specimens.

The Isolation of Vibrio cholera and Other Enteric Bacteria with Molecular Characterization of Vibrio cholera during the Outbreak of Baghdad/Iraq in 2015

Vibrio cholera, causing acute watery diarrhea known as cholera disease, affects all ages and both genders. Cholera infection outbreaks in Iraq have been reported for several years. The recent cholera outbreak, emerged throughout 2015, was investigated using bacteriological laboratory tests, singleplex and multiplex PCR technique for the detection of V. cholera from stool samples. Furthermore the toxigenic potential coupled with the antibiotic susceptibility test for cholera and other bacteria were also investigated. The stool samples were collected from 5698 patients admitted to Al-Yarmouk Teaching hospital and health care centers in Baghdad/Al-Karkh, Iraq, from the 1st of August to the 30th of December 2015. The V. cholera was isolated from 194 cases (3.4% of the cases age between 21 - 50 years). In addition, other enteric infections: Salmonellosis and Shigellosis 7 and 21 respectively, protozoan parasite Giardia lamblia and Entamoeba histolytica 2 and 43 cases respectively were also reported. High percentage of V. cholera infection was detected in October (122 cases, 62.8%), compared with other enteric infections that show high percentage of diarrheal disease in September and November. The results have confirmed that the cholera outbreak was caused by V. cholera O1, biotype El Tor, and serotype Inaba. Seven virulence genes were identified ctxA, toxR, zot, ace, rfbO1, tcpA and ompW. Moreover, the cholera isolated strains were found sensitive to most antibiotic but resistant to nalidixic acid.

Anti-enteric bacterial activity of the traditional medicinal plants of Kanyakumari coast,Tamilnadu,India

Objective:To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria,as most of the pathogens develop drug resistance against commonly used antibiotics.Methods:Crude extracts from different parts of different plants were tested against bacterial strains of clinical significance.Extraction of bioactive principles was done with water and ethanol.Evaluation of antibacterial activity was done by disc diffusion assay against selected bacterial stains.Results:Of the 6 different plant materials tested,extracts prepared from Psidium guajava leaves showed significantly higher efficacy.Extracts prepared using alcohol exhibited higher antibacterial activity when compared to their corresponding aqueous extracts.Conclusions:The findings of the present study suggested that phytochemical extracts of the presently studied plant materials possess significant anti-enteric bacterial activity,and thus lend pharmacological credibility to the suggested traditional use of the plant as a natural remedy for the treatment,management and/or control of gastrointestinal diseases in the coastal tracts of Kanyakumari district,Tamilnadu,India.

The fly factor phenomenon is mediated by interkingdom signaling between bacterial symbionts and their blow fly hosts

We tested the recent hypothesis that the"fly factor"phenomenon(food cur-rently or previously fed on by flies attracts more flies than the same type of food kept inccessible to flies)is mediated by bacterial symbionts deposited with feees or regur-gitated by feeding flies.We allowed laboratory-reared black blow flies,Phormia regina(Meigen),to feed and de fecate on bacterial Luria-Bertani medium solidified with agar,and isolated seven morphologically distinct bacterial colonies.We identified these us-ing matrix-assisted laser desorption/ionization mass spectrometry and sequencing of the 165 rRNA gene.In two-choice laboratory experiments,traps baited with cultures of Pro-teus mirabilis Hauser,Morganella morganii subsp.sibonii Jensen,or Serratia marcescens Bizio,captured significantly more flies than corresponding control jars baited with tryptic soy agar only.A mixture of seven bacterial strains as a trap bait was more attractive to flies than a single bacterial isolate(M.m.siboni).In a field experiment,traps baited with agar cultures of P:mirabilis and M.m siboni in combination captured significantly more flies than lraps baited with either bacterial isolate alone or the agar control.As evident by gas chromatography-mass spectrometry,the odor profiles of bacterial isolates differ,which may explain the additive effect of bacteria to the attractiveness of bacterial trap baits.As"generalist bacteria,"P mirabilis and M.m.sibonii growing on animal protein(beef liver)or plant protein(tofu)are similarly effective in attracting flies.Bacteria-derived airborne semiochemicals appear to mediate foraging by flies and to inform their feeding and oviposition decisions.