| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1152-1 | ||||
Resumo:The antibiotics use in livestock production is a commonly applied practice to prevent or treat a microbial contamination; however, it can contribute to the emergence of resistant bacteria. In fish farming, the use of antibiotics in the feed in order to avoid environmental contamination around the breeding tanks represent a high risk of resistance bacteria emergence. In this way, Salmonella spp. and its many pathogenic serogroups can be distributed in the environment and in the intestinal tract of several animal species, including livestock or wild animals. Thus, the presence of feces and other waste from livestock and/or wild animals around the tanks, caused by failures during biosafety procedures, can serve as sources of Salmonella spp. contamination. Therefore, in the present study we aimed to characterize the antimicrobial profile of 24 Salmonella spp. strains isolated from the aquaculture environments (water, sediments/soil from the slopes of the tanks and feces of domestic and/or free wild-animals) and from round fish raised in aquaculture farms distributed in eight cities, located in the Baixada Cuiabana region in the state of Mato Grosso. The sample collection was performed during the period from November 2021 to May 2022. For this, eleven antibiotics used in human and animal health practices were tested using the disk-diffusion technique, according to the Clinical and Laboratory Standards Institute (CLSI). The strains were stored at -80 °C and were reactivated in Müller-Hinton broth (MH) and incubated at 37 °C between 16 and 18 h. The inoculum was standardized for a concentration of 108 CFU/ml using the McFarland scale. Then, the strains were streaked by swarming (surface streak) on plates containing MH agar. The eleven disk-diffusion antibiotics used were: Penicillin class - ampicillin (10μg), Macrolides class - azithromycin (15μg), Cephem class - cefepime (30μg), cefoxitin (30μg), and ceftiofur (30μg), Fluoroquinolone class - ciprofloxacin (5μg), Phenicol class - chloramphenicol (30μg), Folate Pathway Inhibitor class – trimethoprim and sulfamethoxazole (25μg), and sulfonamides (300μg), Carbapenems class - imipenem (10μg), and Nitrofuran class - nitrofurantoin (300μg). Plates containing antibiotics were distributed equidistant and incubated at 37 °C between 16and 18 h. The strains were classified, according to the halo-size inhibition zones, as sensitive (S), intermediate (I) or resistant (R). Strains with resistance to azithromycin (6/24), sulfonamides (5/24), nitrofurantoin (3/24), sulfamethoxazole/trimethoprim (2/24) and ampicillin (1/24) have been identified. A percentage of 29.17% (7/24) of the isolates were resistant to two combined classes of antimicrobials: Macrolides and Folate Pathway Inhibitor class (5/7), Macrolides and Nitrofuran class (1/7), Penicillin and Nitrofuran class (1/7). The isolates identified as resistant were originated from both environment and fish samples. The presence of Salmonella spp. with antimicrobial resistance in some livestock environments and in fish in the Mato Grosso state shed light in a possible inappropriate use of these antibiotics during animal husbandry and highlights the need of further investigation and continuous monitoring in this livestock system. Palavras-chave: aquaculture, native round fish, Salmonella spp., antibiotics, Mato Grosso Agência de fomento:Secretaria de Desenvolvimento Econômico do Estado de Mato Grosso (SEDEC-MT); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). | |||||