Etiological characteristics of Vibrio cholerae non-O1/O139 strains isolated from a food poisoning in Guangdong

Objective To investigate the drug resistance and molecular characteristics of Vibrio cholera non-O1/O139 strains isolated from a food poisoning in a factory in Guangzhou,Guangdong province in 2014. Methods Biochemical identification, serological identification, drug susceptibility test, virulence-associated gene detection and PFGE molecular typing on six V. choleraenon-O1/O139 strains isolated from a food poisoning in Guangzhou were conducted. Results The biochemical identification and serological identification results indicated that the six strains were all V. cholera non-O1/O139 strains; the drug susceptibility analysis showed that the 6 strains were resistant to ampicillin, cefixime, cefradine, amikacin, tobramycin, gentamycin and polymyxin B, but sensitive to norfloxacin, ciprofloxacin, cotrimoxazole, furazolidone, tetracycline, pipemidic acid, erythromycin and chloramphenicol; The PCR detection of virulence gene showed that all the strains were positive for toxR and hlyA genes, but negative for ctxA, tcpA and ST genes; and the PFGE molecular typing of the strains digested by NotⅠshowed that five strains isolated from the cases and one strain isolated from the inner wall of a refrigerator were in the same type. Conclusion The pathogen of this food poisoning was V. cholera non-O1/O139, which shared common genetic characteristics; and the strains were multi drug resistant. It is suggested to guide the clinical medication based on drug susceptibility test results to reduce the drug resistant strains.