Investigating antimicrobial resistance in Salmonella strains isolated from food in Syria

Background: The emergence of multiple drug resistance in Salmonella typhi and Salmonella paratyphi poses a significant challenge, necessitating the development of effective treatments to combat these bacteria and reduce infection rates. This in vitro study aimed to evaluate the minimum inhibitory concentration (MIC) of various antibiotics against S. typhi and S. paratyphi. Methods: Overall, ۱۱۶ samples were collected from diverse markets in Syria. Molecular techniques, including polymerase chain reaction, were utilized to identify the bacterial genus. Antimicrobial susceptibility testing, employing the disk diffusion method and MIC determination, was conducted to assess the effectiveness of various antibiotics. Results: Among the isolates, ۴۶ were identified, consisting of ۲۳ S. typhi and ۲۳ S. paratyphi strains. Resistance to nalidixic acid was observed in ۹ out of ۲۳ S. typhi and ۱۱ out of ۲۳ S. paratyphi isolates. Notably, these nalidixic acid-resistant strains exhibited elevated MIC۵۰ values for other fluoroquinolones. Furthermore, most of these resistant isolates, specifically ۸ out of ۹ S. typhi and ۱۱ out of ۱۱ S. paratyphi, displayed complete resistance to ciprofloxacin (MIC۵۰≥۲ μg/L). Conclusion: Based on our findings, only gentamicin, third-generation cephalosporins, and some fluoroquinolones demonstrated efficacy effects against S. typhi and S. paratyphi isolates in this study.