Virulence characteristics and multilocus sequence type of Vibrio parahaemolyticus isolated from clinic / 中华检验医学杂志

ABSTRACT

Objective To study on virulence characteristics and multilocus sequence type of Vibrio parahaemolyticus isolated from clinic in Beijing Tongren hospital.Methods Total 152 strains of Vibrio parahaemolyticus isolates were collected from diarrheal patients of outpatients in Beijing Tongren Hospital,Capital Medical University from 2009 to 2011.PCR was used to detect hemolysin gene thermo stable direct themolysin gene (tdh),TDH-related hemolysin gene (trh),type Ⅲ secretion system 2 (T3SS2α,T3SS2β)and systematic functional gene (toxRS/new,orf8) for pandemic 03∶ K6 clone and its derivatives.The genetic features of these strains were determined by multilocus sequence typing (MLST).Results 96％ (146/152) VP harbored tdh gene,2％ (3/152) VP harbored trh gene and 100％ (152/152) VP harbored T3SS2 gene.In this study there were 107 pandemic strains (both tdh and toxRS/new positive and trh negative),38 pathogenic strains (tdh positive and/or trh positive) and 6 nonpathogenic strains (both tdh and trh negative).All nonpathogenic strains harbored systematic functional gene (toxRS/new,orf8).Only one pathogenic strains harbored orf8 gene.One clone harbored all virulence gene.In this study there were 16 sequence types,and ST3 is the pandemic sequence type,including 113 strains,and four new sequence types were found.Conclusions In this study more than 90％ Vibrio haemolyticus harbored tdh gene and ST3 was the pandemic sequence type in Beijing.One can get bacterial pathogenic charateristic and population genetics information by virulence gene testing and MLST.