Etiologic characteristics of food-borne Vibrio parahaemolyticus strains isolated in Guangdong,2014 / 中华流行病学杂志

ABSTRACT

Objective To investigate the serotypes, antimicrobial resistance, virulence genes and molecular characteristics of food-borne Vibrio parahaemolytieus isolated in Guangdong province in 2014.Methods Sixty V.parahaemolyticus strains were tested in this study.The serotyping and antibiotic resistance test were conducted, while the tdh and trh gens of the strains were detected with conventional PCR, and pulsed field gel electrophoresis (PFGE) and multiple locus sequence typing (MLST) were conducted too.Results The 60 strains belonged to 13 serotypes, the major serotypes included O3 K6, O4 K8, O 1 K36 and O4 KUT.The antibiotic resistance test indicated the isolates were highly resistant to ampicillin (100.0％), sulfonamides (43.3％) and cefalotin (28.3％).Up to 56.7％(34/60) of the strains were resistant to two or more antibiotics, and 2 strains showed resistance to three antibiotics.The virulence gene detection indicated that 63.3％ (38/60) of the strains carded tdh+trh-, while only 1 strain carried tdh+trh+.The 60 strains digested by Not I belonged to 48 different PFGE patterns and 3 clusters.The cluster B included the strains isolated from sporadic food borne cases with serotype of O3K6 and similarity of 62.6％-100.0％.The cluster C included O4K8 strains with the PFGE pattem similarity of 56.7％-62.5％.The MLST indicated that the 60 strains had 26 sequence types (STs).The ST-3 was predominant, including 33 strains (serotypes O3K6 and O1 K36).The four O4K8 strains formed another predominant colony, which was different from ST-3.Conclusion The etiologic characteristics of V.parahaemolyticus varied, which might be one of the reasons for high incidence of food-bome V.parahaemolyticus infection in Guangdong.The molecular characteristics of O4 K8 strain were differem from the other predominant serotypes.Close attention should be paid to the possible outbreak caused by O4 K8 strain in this area.