This study investigated the presence and antibiotic resistance of Salmonella spp. in a shrimp farming environment in Northeast Region of Brazil. Samples of water and sediments from two farms rearing freshwater-acclimated Litopenaeus vannamei were examined for the presence of Salmonella. Afterwards, Salmonella isolates were serotyped, the antimicrobial resistance was determined by a disk diffusion method, and the plasmid curing was performed for resistant isolates. A total of 30 (16.12%) of the 186 isolates were confirmed to be Salmonella spp., belonging to five serovars: S. serovar Saintpaul, S. serovar Infantis, S. serovar Panama, S. serovar Madelia, and S. serovar Braenderup, along with 2 subspecies: S. enterica serovar houtenae and S. enterica serovar enterica. About twenty-three percent of the isolates were resistant to at least one antibiotic, and twenty percent were resistant to at least two antibiotics. Three strains isolated from water samples (pond and inlet canal) exhibited multiresistance to ampicillin, tetracycline, oxytetracycline, and nitrofurantoin. One of them had a plasmid with genes conferring resistance to nitrofurantoin and ampicillin. The incidence of bacteria pathogenic to humans in a shrimp farming environment, as well as their drug-resistance pattern revealed in this study, emphasizes the need for a more rigorous attention to this area. 1. Introduction The growing demand for shrimp on the international market has boosted inland shrimp farming over the past decades. Marine shrimp culture located miles away from the ocean is a new and fast growing sector of aquaculture [1]. However, shrimp farmed in both salt water and freshwater are becoming increasingly vulnerable to bacterial infection due to the ease with which pathogens are transmitted in aquaculture [2]. As a result, many farmers have made improper use of antibiotics to prevent or treat infections, leading to the dissemination of antimicrobial-resistant strains in aquatic environments [3]. The increase in the incidence of antimicrobial-resistant strains is also associated with the presence of plasmids containing resistance genes, providing microbiological populations with a greater genetic flexibility and allowing them to adapt and survive in hostile environments [4]. The addition of antibiotics to shrimp fodder for prophylaxis, treatment of infections, or growth stimulation has contributed to the perpetuation of resistant and pathogenic strains as well [5]. Shrimp farm workers are not only regularly exposed to antibiotics as these are mixed with the fodder, but they are also
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