Molecular Epidemiology and Antimicrobial Resistance of Salmonella spp. Isolated from Resident Patients in Mazandaran Province, Northern Iran

Background: Salmonella is one of the causes of food-borne illnesses worldwide resulting in a wide range of human diseases. The aim of this research was to study molecular epidemiology and antimicrobial resistance of Salmonella spp. isolated from resident patients in Mazandaran province, northern Iran. Methods: Totally, 51 stool samples were collected from patients in 20 outbreaks recorded in Health Care Center of Mazandaran province, North of Iran, during October 2013 to September 2014. Cultivation and biochemical methods were used for differentiation of Salmonella. Identified Salmonella isolates were confirmed with 16S rRNA PCR method and sequencing. Antibiotic susceptibility test was carried out for each isolate. Results: Four of 51 samples (7.84%) were contaminated with S. enteritidis. Molecular analysis and sequencing verified the isolates. The delineation level for each isolate discrimination in subsequent analysis was set at 94% for the primer. All of the isolates were resistant to tetracycline, nalidixic acid, and trimethoprim-sulfamethoxazole. No resistance was found to cefotaxime, chloramphenicol, ciprofloxacin, amoxicillin, and ceftazidime. Conclusion: S. enteritidis was the most frequent serovar among salmonellosis outbreaks in the Mazandaran province, Iran. Also, isolated S. enteritidis showed various rates of susceptibility for different antibiotics.