Prevalence and antimicrobial susceptibility profile of Salmonella isolated from food products in the region of Casablanca, Morocco

Introduction: Salmonellosis is a foodborne bacterial disease responsible for food epidemics around the world. The objective of this study is to determine the prevalence and diversity of Salmonella serotypes in several food products isolated at the Casablanca Regional Analysis and Research Laboratory and to test their resistance to different antimicrobials.Methodology: The isolation and identification of Salmonella were performed according to Moroccan standard 08.0.116. All isolates were serotyped and were then tested for antibiotic resistance using the disk diffusion method. The Salmonella isolates were further analyzed by PCR to detect the presence of virulence genes invA. Results:20 different serotypes were identified from 80 strains isolated from 2015 to 2019, the most common of which are S. kentucky (26.3%) followed by S. muenster (10%), S. typhimurium (8.7%), S. menston (7.5%) and S. enteritidis (6.3%). Antimicrobial susceptibility testing revealed that 66.25% of isolates were resistant to at least one of the 14 antimicrobial agents tested. Bacterial resistance was most frequently observed for tetracycline with 46.25%, 45% to sulfonamide, 35% to nalidixic acid, 26, 25% to ampicillin, and 25% to ciprofloxacin. Salmonella serotypes S. montevideo, S. virchow, S. amsterdam, S. anatum, and S. bloomsbury were 100% susceptible to all antimicrobials tested. Examination of Salmonella for invA gene was positive for all the strains.Conclusions: The results of this study have shown that minced meat has a high level of Salmonella contamination, which can be considered one of the main potential sources of human salmonellosis in Morocco.