Campylobacter spp.isolation, its toxin genes detection and molecular subtyping in diarrhea patients in Shanghai in 2014 / 上海预防医学

[ Objective] To investigate the status quo of Campylobacter spp.infection in Shanghai and study its molecular characteristics and virulence and toxin genes. [ Methods ] Stool samples collected from diarrheal patients were cultured for bacterial pathogens using membrane filter method.The strains were identified by biochemical tests and PCR.PCR was applied to detect six virulence and toxin genes including flaA,cdtA,cdtB,cdtC,virB11,cadF.Pulsed-field gel electrophoresis ( PFGE) was carried out for subtyping. [Results] A total of 43 Campylobacter spp.(1.9%) were collected from 2 235 stool samples in Shanghai in 2014 including 41 Campylobacter jejuni isolates(95.3%) and 2 Campylobacter coli isolates(4.7%) .The data showed 100.0%(43/43) of the isolates were positive for flaA and cadF, and 93.0%(40/43) of the isolates positive for cdtA and cdtB.And 88.4%(38/43) of the isolates were posi-tive for cdtC.Only 7.0%(3/43) of the isolates were positive for virB11.Using PFGE, 43 Campylobacter jejuni and Campylobacter coli strains were subtyped into 6 clusters. [ Conclusion] The genes of flaA and cadF are ubiquitous on Campylobacter spp.isolates.The distribution of cdt gene cluster in Campylobacter spp.is high, while that of virB11 is low.The PFGE types of Campylobacter spp.isolated in Shanghai are of diversified and complicated features, which causes mainly sporatic diarrhea.

Partition bands counting established for PFEG fingerprint analysis / 上海预防医学

To establish a new method for PFGE fingerprint analysis , which is easy-to-operate , inexpensive , software-low-dependent and readily-exchangeable . [ Methods ] A group of 44 vibrio parahaemolyticus was subtyped according to PulseNet standardized PFGE protocol .The fingerprint was analyzed with new gel-partition bands counting method and BioNumerics clustering separately and then the results by the two methods were compared with type number , cluster number and Simpson ’ s Index of Diversity ( DI) . [ Results] The 44 isolates could be typed into 32 types and 5 clusters were found by gel-partition bands counting method ( DI=97.6%) .BioNumerics could type the same isolates into 29 types and 4 clusters were found ( DI=95.5%) .The difference in the ability of finding clusters between the two methods was not statistically significant . [ Conclusion] Gel-partition bands counting method is based on the bands distribution among finger print and greatly reduces the number of visually observed spectrum , which is easy-to-operate, inexpensive , software-low-dependent and readily-exchangeable .

Lab-on-chip for the detection of food borne pathogenic bacteria / 上海预防医学

Objective To set up an onsite protocol for abrupt emergencies of public health e-vents, with both the sensitivity and accuracy of the lab-on-chip(microfluidic chip), for the detection of food borne pathogenic bacterium including Vibrio cholera , Salmonella , Vibrio parahaemolyticus and Shigellaare exanimated . [ Methods] By comparison of the results from the chips and fluorescence quantitative PCR were analyzed the specificity , sensitivity, accuracy and repeatability of the Lab-on-chip. [ Results] Acceptable specificity , accuracy and repeatability of the chips had been well achieved , the detection limit of the chips for the Vibrio cholera , Salmonella, Vibrio parahaemolyticus and Shigella was 5 ×103 ~103 DNA Copies/mL. [ Conclusion] Lab-on-chip is believed to be a fast , convenient , efficient tool with accept-able accuracy for public health emergencies .

Characterization of phenotype and molecular characteristics on Vibrio cholerae strains isolated in Shanghai, 1962-2011 / 中华流行病学杂志

Objective To describe the phenotype and molecular characteristics of Vibrio (V.) cholerae strains isolated in Shanghai,from 1962 to 2011.Methods K-B test was used to investigate the antibiotic resistance of V.cholerae strains.PCR was applied to detect seven virulence-related genes including cholera toxin (ctxA),zonula oecludens toxin (zot),accessory cholera enterotoxin (ace),hemolysin (hlyA),toxin-coregulated pilus (tcpA) outer membrane protein (ompU) and the regulatory protein genes (toxR).Genetic relation was assessed by pulsed-field gel electrophoresis (PFGE) and the patterns were clustered by BioNumerics software.Results V.cholerae strains isolated from 1962 to 1996 were sensitive to most of the antibiotics.However,the strains isolated from 2005 to 2011 were resistant to many antibiotics.V.cholerae O 139 group showed higher prevalence of resistance to several antibiotics compared with O l group,and the resistance rate of the O139 toxigenic isolates was higher than that of the non-toxigenic isolates.Most of the O1 strains isolated from 2005 to 2011 were non-toxigenic while O139 strains isolated from 2005 to 2011 were almost toxigenic.There were no strains ofctxA+ detected from the rivers from 2005 to 2011.Main gene type of the O1 strains detected from the aquatic products was hlyA+toxR+ompU+,while that of the O139 strains was hlyA+toxR+ompU+ ctxA + ace +zot + tcpA +.Using PFGE,222 V.cholerae strains were subtyped into 121 molecular types.O139 strains were divided to three clusters and O1 strains to five clusters.Conclusion The characteristics of V.cholerae strains isolated in Shanghai from 1962 to 2011 showed great changes,suggesting that more attention should be paid to the multiplication on antibiotic resistance of V.cholerae strains.