Phenotype and genotypic characteristics of Vibrio parahaemolyticus strains isolated from diarrhea patients in Liaoning province

Objective To examine the phenotype and gene characteristics of Vibrio parahaemolyticus(VPS)strains isolated from diarrhea patients in Liaoning province from 2012 to 2013.Methods A total of 101 VPS strains isolated from diarrhea patients in 2012-2013 were sreotyped.All the strains were tested for drug sensitivity with microdilution broth method.PCR was applied to detect three virulence genes tlh,tdh,and trh.Molecular typing on VPS isolates was completed with pulsed-field gel electrophoresis(PFGE)and the patterns were clustered by BioNumerics software.Results The 101 isolates were belonged to 25 serotypes,with a dominant serotype of O3:K6(37.62%,38/101).The strains isolated from the diarrhea patients were resistant to sulfamethoxazole,streptomycin,and ampicillin,while with high sensitivity to ciprofloxacin,doxycycline,cefepime,trimethoprim,imipenem,and ceftriaxone.Virulence gene detection showed that all the strains were positive to tlh and the most of the strains were positivie to tdh(84.16%,85/101),but all the strains were negative to trh.The positive rate of tdh among O3:K6 strains(100%)was higher than that among non-O3:K6 strains(76.19%,77/101)(P=0.000 81).The 101 isolates were discriminated into 63 different PFGE patterns,while 38 O3:K6 strains into 19 patterns without cluster characteristics.Conclusion Vibrio parahaemolyticus strains isolated from diarrheal patients in Liaoning province from 2012 to 2013 were dominated by O3:K6 serotype,with stronger virulence and high positive rate of tlh and tdh gene.Vibrio parahaemolyticus strains showed high sensitivity to most antibiotics.The prevalent Vibrio parahaemolyticus strains in Liaoning province present various clonal origins.