Resumo

Enterococcus sp. contributes to the occurrence of desirable organoleptic properties for certain types of foodstuffs, including cheese. However, the performance of some species as opportunistic pathogens in human infections is known. One factor that contributes to the pathogenicity of Enterococcus sp. is the increase resistance to antibiotics, especially vancomycin. The aim of this study was to evaluate Enterococcus sp. isolates of minas fresh cheese and clinical samples, about their sensitivity to different antibiotics and presence of resistance genes. A total of 30 clinical isolates and 103 food isolates were evaluated for their resistance to three antibiotics: tetracycline-30μg, erythromycin-15ug and vancomycin-30μg, through the disk diffusion test in Mueller-Hinton agar. The reading of inhibition zone was performed according to CLSI criteria. The molecular biology technique of PCR was used to determine the markers of resistance to erythromycin [erm(B)], tetracycline [tet(L)], gentamicin [aac (6'')-Ie-aph(2')-Ia] and vancomycin [vanA]. Of the Enterococcus sp. species tested 7 were identified as E. faecalis and 23 as E. faecium in clinical isolates, and 38 as E. faecalis, 61 as E. faecium and 4 as Enterococcus spp. in isolates from food. The in vitro assessment of the sensitivity of Enterococcus sp. indicated that the food isolates were resistant to erythromycin, vancomycin and tetracycline 23.3%, 3.9% and 16.6%, while the clinical were 80%, 66.7% and 43.3%, respectively. The antibiotic gentamicin was not evaluated by disk diffusion. Regarding the presence of the resistance genes we found that 52.4%, 28.1%, 1.9% and 2.9% of the isolates of food and 80%, 23.3%, 86.7% and 66.7 % of clinical isolates were genes for vanA, tet(L), erm(B) and aac(6'')-Ie-aph(2')-la, respectively. Note that not all of the isolates with the resistance gene were expressing antibiotic resistance. These results demonstrate that isolated enterococci cheese rennet are resistant to a range of antibiotics in clinical use. This is the most important data in this study and serves as a warning to the public health authorities, since these antibiotics represent the last therapeutic option in the treatment of nosocomial infections. The resistance to antimicrobial agents found in Enterococcus sp. indicates the necessity of controlling the spread of resistant strains by the consumption of food.