Salmonella spp: Prevalence, antimicrobial resistance and molecular typing of strains isolated from poultry in Tetouan-Morocco

Salmonellosis is one of the most common foodborne illnesses in the world. The irrational use of antibiotics in medicine and in animal nutrition has greatly favored the emergence and spread of resistant strains of nontyphoid Salmonella. 620 samples from poultry samples were biochemically analyzed for the presence of Salmonella according to ISO 6579 and molecularly confirmed. The selected positive strains were tested for antibiotic susceptibility, characterized to the levels of species, subspecies and serovars using PCR. Furthermore, they were typed using MLST and MLVA, and phylogenetically grouped by MLSA. Prevalence of Salmonella enterica subsp. enterica was 9.84%, grouped in seven serovars, with a major presence of serovar S. Hadar (23.80%), S. Typhimurium and S. Chester (19.05% for each serovar), followed by S. Schwarzengrund (14.28%), S. Kentucky, S. Bredeney (9.52%) and S. Saintpaul (4.76%). Drug susceptibility testing showed that 80.95% of Salmonella isolates were resistant to at least one antibiotic and 19.05% were susceptible to all antibiotics tested. Nine different MLST STs (sequence types) were detected, ST1954 being the most common, which was mostly found in S. Chester isolates from poultry. There was a marked change in the serovars and antimicrobial resistance profiles of Salmonella isolates in this study compared to those in previous studies.