Surveillance analysis of Yersinia eterocolitica in Gaomi City, Shandong Province

Abstract

Objective To investigate the distribution of host animals and the serological distribution and virulence gene of Yersinia eterocolitica in Gaomi City. Methods Sample stools of poultry and domestic and diarrhea patients, as well as flies and chilled (frozen) poultry and domestic animal meats in Gaomi City were preliminarily identified and the suspected strains isolated were sent to Shandong Provincial Center for Disease Control and Prevention for further identification from 2012 to 2015. The bacteria were analyzed by the systematic biochemistry to determine the serotypes, bio-types and virulence genes[Yersinia enterocolitica adhesion aggression site gene (ail), heat-tolerance enterotoxin gene (ystA), organism type 1A enterotoxin gene (ystB), adhesin (yadA), yop regulator transcription activation action factor (virF)]. Results Eighty-five stains of Yersinia enterocolitica were detected in 2 860 specimens and the detection rate was 3.0% (85/2 860). The chicken strains accounted for 50.6% (43/85), the swine strains accounted for 20.0% (17/85), and the sheep strains accounted for 10.6% (9/85). In all the serotypes, the highest was O∶8(24.7%, 21/85), followed by O∶5 (12.9%, 11/85), the bacteria were detected in the stools of chickens, duck, and swine etc., as well as in diarrhea patients and chilled (frozen) poultry and domestic animal meats, biotype is 1A. One strain O∶3/4 was detected from swine stool with ail, ystA, yadA and virF genes. Conclusions The Yersinia enterocolitica is widely distributed and both pathogenic and non-pathogenic strains co-exist in Gaomi City; the main serological types are O∶5/1A and O∶8/1A; the pathogenic serotype is O∶3/4, and chicken, swine and sheep are the main host animals. Key words: Yersinia enterocolitica; Animal host; Serological types; Virulence gene