Characterization of Yersinia enterocolitica Biotype 1A Strains Isolated from Swine Slaughterhouses and Markets

Abstract

Yersinia enterocolitica is an important foodborne pathogen that causes illness in humans and animals. Y. enterocolitica is also the most heterogeneous species of the genus and is divided into distinct serotypes and over six biotypes. Y. enterocolitica biotype 1A strains are classically considered as nonpathogenic; however, some biotype 1A isolates have been considered as causative of gastrointestinal disease, yielding symptoms indistinguishable from those produced by pathogenic biotypes. Even after decades of isolation of clinical strains, the pathogenic mechanisms of these isolates are still not fully understood. In the present study, 122 Yersinia enterocolitica biotype 1A strains isolated from swine slaughterhouses and meat markets in Sao Paulo, Brazil, were characterized according to the presence of the virulence genes ail, virF, and ystA. A total of 94 strains were positive to at least one virulence gene (77.05%), and 67 were positive to all of them (54.92%). Twenty-two strains were submitted to PFGE genotyping resulting in 22 distinct pulsotypes, varying from 50% to 84% of genetic similarity. Any clustering tendency among pulsotypes related to origin, isolation site, or even virulence profile was not observed. The present study reports an important contamination of the environment in swine slaughterhouses, meat markets, and pork, by potentially virulent Y. enterocolitica biotype 1A.

Phenotypic and genotypic analysis of bio-serotypes of Yersinia enterocolitica from various sources in Brazil

“…The strains of this biotype have generally been regarded as avirulent. The genes present in such strains match findings in Brazil [29] and worldwide [30], demonstrating the pathogenic potential of the representatives of this biotype.…”

Genotypic Characterization ofYersinia enterocoliticaBiotype 4/O:3 Isolates from Pigs and Slaughterhouses Using SE-AFLP, ERIC-PCR, and PFGE

“…These isolates were previously obtained, as described by Paixão et al [15], in tonsils, swabs from slaughterhouses and in market environment points, and pork gathered from 12 collections conducted between 2007 and 2008. …”

Genome Wide Search for Biomarkers to Diagnose Yersinia Infections

“…It may be remarked that these genes have not been reported earlier as biomarkers for identifying Yersinia. Previously, the genes involved in pathogenesis: (i) ail, inv, yst, myf, vir, and yop have been used for identifying Yersinia [16][17][18][19]. Incidentally, these 5 genes are not present in all the strains of Yersinia, making it difficult to use them as universal biomarkers [39,40].…”

“…[12]. The assays commonly used for identifying Yersinia, involve genes responsible for pathogenesis: (i) ail (attachment and invasion locus, 454 nts), (ii) inv (invasion, 570 bp), or (iii) yst (Yersinia stable toxin, 145 nts), (iv) myf (adhesin), and (v) yop (yersinia outer protein), (vi) vir (transcriptional regulator, 700 nts) genes [16][17][18][19]. The process is hindered by the presence of DNA from closely related competing microflora.…”