Genetic similarity, antibiotic resistance and disinfectant susceptibility of Listeria monocytogenes isolated from chicken meat and chicken-meat processing environment in Mato Grosso, Brazil

Abstract

A trial was conducted to determine the genotypic and phenotypic profiles of Listeria monocytogenes (LM) isolated from chicken meat and chicken-meat processing environment in an export-authorized industrial facility in Brazil. A total of 37 LM isolates were separated according to their genetic similarity by pulsed-field gel electrophoresis (PFGE), classified by serotype and lineage using multiplex PCR, tested for antibiotic resistance using the disk-diffusion technique, and analyzed for disinfectant susceptibility using the minimal inhibitory concentration (MIC) approach. The majority of the isolates belonged to lineage II, serotypes 1/2a or 3a. Genotypically, isolates from packaged frozen carcasses and knives & boards of the cutting room were similar to those of carcasses after chiller. Isolates from packaged frozen boneless thighs, however, were very peculiar. Regardless the origin, high level of resistance to peracetic acid, ampicillin and sulfonamides were detected. Overall, our findings suggest that the prevalence of LM in the cutting room is not sustained by the continuous flow of new bacteria, but mainly by an already established microbiota that persists in the environment. Therefore, more effective strategies of cleaning and disinfection must be adopted by the chicken meat industry in order to reduce the prevalence of LM in the processing environment.