Prevalence and Antimicrobial Resistance of Escherichia coli in Ready-to-Eat Vegetables and Salads in Mashhad

Introduction: The rising global consumption of ready-to-eat (RTE) vegetables has highlighted concerns about their microbiological safety, particularly regarding contamination with antibiotic-resistant Escherichia coli (E. coli). This study aimed to isolate E. coli from green vegetables and salads sold in Mashhad, Iran, and assess their antimicrobial resistance profiles. Methods: A total of ۱۲۰ RTE vegetable samples were analyzed using microbiological procedures outlined in the Iranian National Standard ISIRI ۲۹۴۶. Confirmatory identification of E. coli was performed via culture-based methods and indole testing. Antibiotic susceptibility was evaluated using the Kirby-Bauer disk diffusion method, following CLSI guidelines. Results: Out of ۱۲۰ samples, ۴۰ (۳۳.۳۳%) tested positive for E. coli. The highest susceptibility rates were to nalidixic acid (۵۷.۵%) and chloramphenicol (۵۵%). However, significant resistance was observed against cefazolin (۶۷.۵%), cefixime (۶۲.۵%), and ciprofloxacin (۶۲.۵%). Intermediate resistance to colistin (۴۷.۵%) raises concern due to its role as a last-resort antibiotic. Multidrug resistance (MDR) was prevalent, with ۸۰% of isolates resistant to at least two antibiotics. Conclusion: The detection of multidrug-resistant Escherichia coli in one-third of RTE vegetable and salad samples from Mashhad highlights a significant public health concern. These findings underscore the urgent need for enhanced hygiene practices, regular microbial surveillance, and antibiotic resistance monitoring to ensure the safety of RTE produce and prevent potential transmission of resistant strains through the food chain.

کلیدواژه ها:

Escherichia coli ، Vegetables ، Salads ، Antimicrobial resistance ، Mashhad