Avaliação de resistência aos antibióticos em bactérias isolada de carne bovina

Abstract

Brazil leads the export ranking and is the second largest consumer of bovine meat in the world. Rio Grande do Sul is responsible for approximately 6.5% of the national production, and the majority of production of bovine meat from the state is destined for consumption by state itself, considering that the barbecue is considered the typical dish of the region. Antimicrobials are widely used in food-producing animals for prophylaxis, treatment and, mainly, as growth inducers. Inappropriate use of antimicrobials in animal production may leave residues in animal tissues. A significant fraction of these antimicrobials applied in veterinary practice is equivalent to the drugs classified by the World Health Organization as "critically important" in human therapy for the treatment of infections. Thus, the objective this study was determine the antibiotic resistance profile, detect presence of beta-lactamases and antimicrobial residues, and evaluate the viability bacteria under the action of temperature in bovine meat. In the period between June 2017 and August 2018, 45 bovine meat samples were purchased from different supermarkets and butchers in the city of Uruguaiana, Rio Grande do Sul, Brazil. A 25 g portion was aseptically removed from the inside each sample and added in 225 mL of peptone water. Serial dilutions (10-1 to 10-5) were inoculated on sheep blood agar and MacConkey agar plates incubated at 35 ° C for 24 h. Colonies with different morphological characteristics were selected and submitted to the Gram staining technique and identified by biochemical tests. Antimicrobial susceptibility testing was performed using the disk diffusion method. Confirmation of the production of extended- spectrum beta-lactamases (ESBL) was performed by the disk synergy method and the production of carbapenemase by the combined disck method. Antimicrobial residue analysis was performed by liquid chromatography–tandem mass spectrometry (LC-MS / MS). A total of 161 enterobacteria, including 50 ESBL-producing and 8 carbapenemase producers, 15 Gram-positive cocci and 3 Gram-positive bacilli were isolated. Overall, important resistance profile was detected, especially for beta-lactam antibiotics. Three bovine meat samples were tested at different temperatures and a total of 34 microorganisms were isolated, with raw meat (n = 16), medium-rare (n = 12) and well done(n = 06). It was observed that even under the action of temperature many microorganisms remained viable in the samples of barely cooked and roasted meat. Moreover, the isolates showed resistance to different antibiotics tested. No antimicrobial residues were detected in the samples evaluated. It was possible to observe the occurrence of resistant microbial contamination in bovine meat samples analyzed, including ready-to-eat meat samples, suggesting that there may be a correlation between the presence of these microorganisms in bovine meat and the transfer of resistance to dietary intake.