Evaluation of bulk tank raw milk and raw chicken meat samples as source of ESBL producing Escherichia coli in Turkey: Recent insights

Abstract

Extended spectrum beta-lactamase producing Escherichia coli (ESBL-EC) was detected in 86.6% of chicken and 22.6% of bulk tank milk (BTM) samples. Pulsed-field gel electrophoresis analysis revealed 49 distinct restriction profiles among 66 isolates, and 62.3% of the isolates carried the bla(CTX-M) gene, among which CTX-M-1 was found to be the predominant ESBL types in chicken isolates, whereas CTX-M-15 was the commonest among BTM samples. Additionally, of 52 ESBL-EC isolates from chicken meat samples, 36.5%, 9.6%, and 7.7% harbored the bla(TEM), bla(CMY-2), and bla(SHV-12) genes, respectively, compared with 28.5% of the bla(TEM) and 7.1% of the bla(SHV-12) markers among BTM isolates. The fimH gene was present in 51 isolates of chicken and in 14 isolates of BTM samples, while other virulence genes iutA (n = 31), iroN (n = 26), kpsMT II (n = 5), papC (n = 2), papG allele II (n = 2), papG allele II-III (n = 2), and papEF (n = 2) were only present in chicken meat isolates. Overall, it can be said that contaminated chicken meat and BTM might serve as vehicles for playing potential role in zoonotic transmission of ESBL-EC to humans in Turkey. Practical applications Extended spectrum beta-lactamase producing E. coli (ESBL-EC) have been considered to be one of the major worldwide clinical problems and have been frequently isolated from the foods of animal origins such as chicken meat, fish, and raw milk. The current study aimed to isolate ESBL-EC from chicken and bulk tank milk samples and further characterize the strains by PFGE, identifying resistance genes and as well as virulence genes. Given the high prevalence of CTX-M-15/55 type ESBL-EC strains possessing important virulence genes in chicken and milk samples, it can be said that foods of animal origins might be an important risk factor for extraintestinal ESBL-EC infections for humans.