Molecular identification of Enterococci isolated from artisanal cheeses

Abstract

Enterococci are relevant for improving and developing the flavor and quality of cheese. E. faecalis is the commonest specie isolated from artisanal cheeses. Strains of E. faecium (EVR) are also recovered from artisanal cheeses, being the reason of human infections. EVR develops multi-resistance to different antimicrobials such as aminoglycosides, ß lactams and glycopeptides. Aims: To correlate the phenotypic and genotypic identification of the enterococci isolates from artisanal cheese manufactured in farms settle in Tandil, BAprovince. Methods: 21 artisanal cheeses were processed. The phenotypic characterization was performed by the API System, whilst the molecular identification of the strains was undertaken by PCR amplification of tuf and sodAgenes. Results: 13 strains of enterococci were isolated from cheeses, by which 9 strains were phenotypically identified as E. faecalis, whilst 4 isolates were not typified. PCR revealed that all the strains tested were identified as E. faecium. Conclusions: The phenotypic characterization is not a reproducible and reliable method to identify enterococci. In contrast, the genotyping techniques, allows a fast and accurate identification of those strains. In artisanal dairy products is pivotal to identify other species than E. faecalis that may become as emergent pathogens in human (EVR).