Molecular Characterization of Enterococcus faecalis and Enterococcus faecium Isolated from a Meat Source in Shahrekord Local Markets, Iran

Abstract

Enterococcus faecalis (E. faecalis) and E. faecium (E. faecium) are commensals of the gastrointestinal biota of humans and animals and are considered opportunistic pathogens. This study aimed to improve the knowledge about E. faecalis and E. faecium isolated from meat. To this end, 104 meat samples were collected from sheep, goats, cattle, and calves from Shahrekord local markets in Iran. Presumptive colonies of E. faecalis and E. faecium were isolated from the samples and subjected to identification tests. Antimicrobial susceptibility was determined using the Kirby-Bauer disc diffusion method, and polymerase chain reaction (PCR) was performed to detect some virulence genes. Furthermore, randomly amplified polymorphic DNA typing and repetitive element sequence-based PCR fingerprinting were used to show the clonal relatedness of the isolates. The results revealed that enterococci were present in 90 out of 104 samples. Specifically, E. faecalis and E. faecium were the commonly isolated species, with the predominance of E. faecalis, which exhibited high resistance to streptomycin (95%) but was susceptible to vancomycin (85.6%). Virulence genes detection showed that ccf and cpd genes were the most prevalent genes in both species. In addition, the molecular typing method indicated that the isolates belonged to separate subgroups. This study shows the contamination of meat products by potential pathogens and resistant enterococci. There is a need to implement regular surveillance to monitor the emergence of antimicrobial-resistant E. faecalis and E. faecium in food, particularly in meat production.