Molecular typing, antibiotic resistance profiles and biocide susceptibility in Salmonella enterica serotypes isolated from raw chicken meat marketed in Venezuela.

Abstract

Salmonella is a common bacterial cause of foodborne diarrhea worldwide. The purpose of this study was to characterize antimicrobial resistance and susceptibility to biocides in Salmonella enterica serotypes isolated from raw chicken meat, as well as to study the genetic relationship between strains and virulence profiles. Nine Salmonella enterica strains (5 S. Heidelberg; 2 S. Enteritidis; 1 S. Typhimurium and 1 S. Meleagridis) recovered from raw chicken meat marketed in the urban area of Mérida, Venezuela, were studied. Phenotypic characterization was based on antimicrobial susceptibility testing as well as detection of extended-spectrum β-lactamases (ESBLs) by double-disc synergy. The susceptibility to biocides was determined using the dilution-neutralization methods. The detection of quinolone resistance-determining regions of gyrA, gyrB, and parC genes, bla ESBLs genes, plasmid-mediated quinolone resistance determinants and virulence genes (invA and spvC) was carried out by PCR. All strains were typed using PFGE. Multidrug-resistance was evident in 6 of 9 strains studied. However, all Salmonella serotypes were susceptible to the tested biocides. Genotypic characterization determined that 5 strains harbored the bla CTXM-2, 4 bla TEM-1 and 3 qnrB19 genes. All strains were positive for the invA gene. The spvC gene was detected in 4 of them. PFGE grouped Salmonella strains into 4 different patterns that represented individual serotypes. This study provides valuable information on antibiotic resistance, biocide susceptibility profiles, virulence gene content and genetic diversity of Salmonella enterica serotypes isolated from raw chicken meat marketed in Venezuela, and evidenced a health risk for consumers.