Microbiological Monitoring and Microbial Susceptibility of Salmonella from Aquacultured Tambaqui Hybrids (Colossoma macropomum): Implications for Food Safety

<b>Background:</b> Salmonellosis is a foodborne illness typically associated with gastroenteritis following the ingestion of products contaminated with <i>Salmonella enterica</i>. Although the aquatic environment is not a natural reservoir for <i>Salmonella</i> spp., its occurrence has been reported in various aquacultured species worldwide, including species from the Amazon Basin in South America. The World Health Organization has classified the emergence of multidrug-resistant (MDR) <i>Salmonella</i> strains as a global priority, underscoring the importance of monitoring antimicrobial resistance to mitigate public health risks. This study aimed to detect <i>Salmonella</i> spp. serotypes of clinical relevance to humans (<i>S.</i> Typhi, <i>S.</i> Paratyphi, <i>S.</i> Typhimurium, and <i>S.</i> Enteritidis) in farmed tambaqui hybrids and to assess the antimicrobial susceptibility of the isolates. <b>Methods:</b> A total of 55 <i>Salmonella</i> spp. strains, previously isolated from tambaqui hybrids (<i>Colossoma macropomum</i>) produced in fish farms in Mato Grosso, Brazil, were evaluated. Identification and susceptibility profiling were performed using the VITEK^®2 Compact automated system (BioMérieux, Marcy l'Étoile, France), testing 14 commonly used antimicrobials, including amoxicillin-clavulanic acid, piperacillin-tazobactam, cephalexin, cefuroxime axetil, ceftriaxone, cefepime, meropenem, ertapenem, amikacin, gentamicin, ciprofloxacin, and sulfamethoxazole-trimethoprim. <b>Results:</b> All isolates were confirmed as <i>Salmonella</i> spp., with no detection of clinically important serotypes. Moreover, all 55 strains were susceptible to the 14 antimicrobials tested. <b>Conclusions:</b> These findings indicate a low risk of pathogenic or resistant <i>Salmonella</i> from farmed tambaqui hybrids under the evaluated conditions. Nevertheless, ongoing microbiological monitoring remains essential, particularly in light of regulatory standards that prohibit the presence of <i>Salmonella</i> spp. in fish products and the potential emergence of MDR strains.