| Congresso Brasileiro de Microbiologia 2023 | Resumo: 636-2 | ||||
Resumo:Excessive use of antimicrobials for non-clinical purposes has recurrently been observed, especially in animal husbandry. Antimicrobials in livestock farming can prevent and control opportunistic diseases, ensuring optimal development of animals and yield. On the other hand, this has become a problem as it induces the selection of resistant bacteria, mainly those from the Enterobacterales order, impacting the effectiveness of antimicrobial therapy. This study aimed to investigate isolates of enterobacteria resistant to ceftazidime in the intestinal microbiota of swine raised on a farm in the region of Sacramento-MG. We collected rectal swabs from 33 swines representative of the investigated population. Samples were transported in Cary Blair medium to the Microbiology Laboratory where they were grown on MacConkey agar with 1 g/L of ceftazidime (CAZ). The isolated Enterobacteriaceae species were phenotypically identified and characterized according to the antibiogram by the diffusion disk method, having the expression of extended-spectrum beta-lactamases (ESBL) evaluated by DDS. Bacteria capable of growing in the medium containing CAZ were recovered from samples of 27 swine (81.8%). Since one of the pigs had two bacterial isolates, the isolated totaled 28 bacteria. Escherichia coli was the predominant species, identified in 23 out of the 28 isolates. One was identified as Pantoae agglomerans from the remaining five and the other four as non-fermenting bacilli. All E. coli isolates demonstrated resistance to amoxicillin, cephalothin, and tetracycline. Furthermore, only 4.3% of them were susceptible to ciprofloxacin and sulfamethoxazole with trimethoprim; only 21.7% to cefepime; 30.4% to ceftazidime and 43.5% to cefotaxime. The E. coli population studied showed greater susceptibility to carbapenems (100%), followed by gentamicin (91.3%), nitrofurantoin (82.6%), amoxicillin with clavulanate (78.3%), amikacin and aztreonam (both with 74%). In addition, ESBL expression was detected in 17 of the 23 E. coli identified, explaining the low susceptibility to amoxicillin and 1st, 3rd, and 4th generation cephalosporins and the high susceptibility to ESBL-stable beta-lactams. The high prevalence of ESBL-producing E. coli found in this study may have been due to the use of amoxicillin as a food supplement for the animals. Following to the farm's feeding protocol, piglets 30 to 40 days old had amoxicillin administered daily, in the ratio of 100 g to 500 kg of feed. Thus, these results highlight the risk of using amoxicillin as an additive in swine feeds, which may favor the selection of E. coli capable of producing ESBL and becoming resistant to several antimicrobials. Palavras-chave: Enterobacteriaceae, Rectal microbiota, Resistance to Ceftazidime, Swines, ESBLs Agência de fomento:University of Ribeirão Preto | |||||