[Profile of antimicrobial resistance in isolates of Staphylococcus spp. obtained from bovine milk in Colombia].

Staphylococcus spp. is one of the pathogens that cause bovine mastitis and may present multiple resistance to different antimicrobial groups. The aim of this study was to phenotypically identify Staphylococcus spp. isolates obtained from bovine milk and to characterize their antimicrobial resistance profile. The 101 strains were classified by phenotypic tests, their resistance to oxacillin, cefoxitin, penicillin, ampicillin, tetracycline, kanamycin, sulfamethoxazole / trimethoprim, clindamycin and erythromycin was determined by the Kirby-Bauer technique and the presence of resistance genes by PCR. A total of 65 strains was S. aureus and 36 strains were coagulase-negative staphylococci (CoNS). We found different patterns of resistance to antibiotics evaluated in strains of S. aureus and CoNS, only the resistance to ampicillin was found associated with the species (p<0.005). In the 101 strains, the mecA gene was detected in 27%, aph(3')-IIIa in 75.2%, aac(6')/aph(2")-3 in 47.4%, ant(4')-Ia in 32.7%, tetM in 63% and tetK in 43.6%; however, no association was found with the resistance to penicillin, ampicillin, cefoxitin, kanamycin and tetracycline, respectively (p>0.05). On the other hand, the blaZ gene was found in 59.4% of the 101 strains and the ermCgene in 62.3%, which was associated with resistance to β-lactams and macrolides, respectively (p<0.001). In this study, antimicrobial multiresistance was found in S. aureus and CoNS strains. This finding impacts on the dairy industry, representing a risk to public health.