Evaluation of Multi-drug Resistant Escherichia coli Isolated from Locally Manufactured Ready-to-Eat Tomato Sauces

Sauces, commonly consumed with fast foods, are nutritious food additives but can become contaminated due to improper storage, unhygienic preparation conditions, and poor raw ingredient quality. The low pH and nutrient content of sauces can support the growth of acid-loving microorganisms, including fungi. This study aimed to isolate, identify, and assess the antibiotic resistance of multi-drug resistant Escherichia coli (E. coli) from locally produced tomato sauces used by street food vendors in Dinajpur. A total of 60 tomato sauce samples were collected aseptically and analyzed in the Bacteriology Laboratory. Bacterial identification involved cultural, morphological, biochemical, and molecular methods. Cultural examination revealed typical E. coli growth on nutrient broth, nutrient agar, MacConkey's agar, and Eosin Methylene Blue agar. Biochemical tests confirmed E. coli through positive reactions for Indole and Methyl Red tests and negative reactions for Voges-Proskauer and Citrate utilization tests. PCR analysis confirmed the presence of E. coli by amplifying a 232 bp DNA fragment. Antibiotic susceptibility testing showed that the E. coli isolates were sensitive to ciprofloxacin, ceftriaxone, enrofloxacin, azithromycin, levofloxacin, tetracycline, and doxycycline whereas resistant to amoxicillin, ampicillin, and cefixime. The findings emphasize the importance of ensuring proper hygiene and quality control during the preparation and serving of tomato sauces.