[Etiologic characteristics of Vibrio cholerae in Guangdong province in 2009-2013].

OBJECTIVE:To analyze the etiologic characteristics of O1/O139 Vibrio cholerae in Guangdong province in 2009-2013. METHODS:Isolates from cholera cases and from the environment surveillance points were investigated by serological typing, antibiotic susceptibility testings, toxic genes detection and molecular typing to analyze the similarities and differences of the identified species. RESULTS:Totally, 190 isolations of O1/O139 V. cholerae were obtained from cholera cases (16 strains) and environmental samples (174 strains) in Guangdong province in 2009-2013. The sero-types would include Inaba (3 isolates), Ogawa (7 isolates) and O139 (6 isolates) in all the isolates from the cholera cases. Ten strains from the ctxA positive cases were detected by PCR. Two Ogawa strains carried incomplete CTXΦ phage. Results from the antibiotic susceptibility test indicated that 5 strains were absolutely sensitive to 11 antibiotic discs in vitro, while another 3 strains were simultaneously resistant to 4 antibiotic discs. Except for 2 stains, all the O139 strains from the environment were ctxA negative, detected by PCR. Incomplete CTXΦ phage was found in the Inaba (53 isolates), Ogawa (22 isolates) and O139 (2 isolates), respectively. Results from the antibiotic susceptibility test exhibited that 25 strains were resistant simultaneously to 4 and/or more antibiotic discs, especially the Inaba strains from the seafoods(13 isolates). 2 Inaba strains from seafood were simultaneously resistant to 7 antibiotic discs. Results from PFGE molecular typing indicated that the PFGE types digested by Not I expressed significant diversity. Inaba and O139 strains from cases were gathered in the same clusters, while the Ogawa strains from cases scattered in different clusters but no significant correlation among these strains were found. Our results suggested that a distant genetic relationship might exist between these two different sources strains. CONCLUSION:Complex and diverse as the virulence genes and genetic characteristics and with the grim situation of multi-drug resistant strains, all seemed important to strengthen the surveillance programs on the variation of strain types and antibiotics resistance of O1/O139 V. cholerae in Guangdong province.