Drug resistance and molecular characteristics of non-O1/O139 Vibrio cholerae isolated from diarrhea cases in Guangdong province between 2011 and 2013

Objective To analyze phenotypic and molecular characteristics of non-O1/O139 Vibrio cholerae(V.cholerae) strains isolated from diarrhea cases in Guangdong province between 2011 and 2013.Methods Totally 24 non O1/O139 V.cholerae strains were isolated(20 from diarrhea cases,4 from seafood)in Guangdong province between 2011 and 2013.The antimicrobial susceptibility of the strains was assessed with K-B test;virulence genes were determined by PCR;and molecular typing was carried out by pulsed field gel electrophoresis(PFGE).Results Antimicrobial susceptibility test showed that of the 24 strains,17 were resistant to trimethoprim sulphamethoxazole,9 to nalidixic acid,and 5 to tetracycline,with the resistant rate of 70.8%,37.5%,and 20.8%,respectively,while all the strains were sensitive to ceftriaxone and amikacin.PCR detection of virulence gene showed that all the strains were positive for hlyA and toxR gene,but negative for ctxA,tcpA,ace,zot,and st genes.PFGE molecular typing of the strains digested by NotⅠdemonstrated significant diversity among the strains,especially between the strains isolated from cases and seafood.Conclusion The virulence genes and genetic characteristics of non-O1/O139 V.cholerae strains isolated from diarrhea cases in Guangdong province was complex and were highly resistant to many antimicrobial agents,suggesting the importance to strengthen the monitoring of the genetic variation and drug resistance of the isolated strains in Guangdong province.