Resumo

Enterococcus spp. are a widely-distributed bacterial group that can be found as commensals of gastrointestinal tract of warm-blooded animals as well as in meat and dairy foods. Due to their glycolytic, proteolytic and lipolytic activities, enterococci have been employed as starter cultures in the food industry. Dualistically, these bacteria are also able to cause several diseases, such as bloodstream infection and endocarditis. The aims of this study were to evaluate the frequency and distribution of enterococci species in selected food samples (cheese, poultry and pork meat, and vegetables), and evaluate the presence of antimicrobial resistance (for vancomycin and high-level aminoglycosides) and virulence determinants (hemolysins and gelatinase) in the isolates. For comparison purposes, isolates recovered from bloodstream infections of patients attended at Botucatu Medical School – Univ Estadual Paulista – UNESP, were also evaluated for the same tests. Food samples were purchased on Botucatu SP Brazil supermarkets and groceries and transported, under refrigeration, in isothermal boxes until processing at the lab in the same day. Recovery of enterococci from food was made in bile esculin azide media. Both food and bloodstream infection isolates were identified by using phenotypic tests; hemolysin and gelatinase were detected on specific media; antimicrobial susceptibility was determined by disk diffusion methodology. A number of 158 enterococci strains were isolated from 100 out of 105 (95.2%) food samples being E. faecium (41.8%) and E. faecalis(20.3%) the most frequent species; neither E. gallinarum nor E. casseliflavus were isolated. E. faecalis was also the predominant (94.7%) species among the 57 bloodstream infecting enterococci. Phenotypic characterization did not allow a clear differentiation between food and bloodstream isolates since gelatinase and hemolysin were produced by both groups of isolates. No vancomycin resistance was detected, and high-level gentamicin resistance was observed only in bloodstream isolates (24.6%). High-level streptomycin resistance was observed in a few isolates, both of food (2/158) and bloodstream infections (3/57). Our results alert to the high frequency of enterococci isolated from food, and to their potential role as environmental reservoir of virulence and resistance traits. Financial Support: FAPESP 2008/58768-3.