Plasmid-mediated dissemination of antimicrobial resistance among multidrug-resistant bacteria isolated from food-contact surfaces in university cafeterias

Abstract Microbes are the cause of foodborne illnesses, a serious global public health concern that present continuous medical and financial difficulties. In seven student cafeterias at the University Campus Peshawar, the prevalence and patterns of antibiotic resistance of multi-drug resistant bacteria isolated from food contact surfaces were examined. 42 swab samples were taken from utensils, such as plates, forks, spoons, drinking glasses, cutting boards, and washing water. The isolates were identified by molecular characterization by PCR amplification of the 16S rRNA gene and biochemical assays after the samples were cultivated on MacConkey Agar. With an occurrence rate of 44.44%, E. coli had the highest prevalence, followed by S. Typhi (25.93%), S. aureus (18.52%), P. aeruginosae (11.11%), and Enterobacter spp. (7.04%). The highest rates of bacterial contamination were found on cutting boards (37.3%) and in washing water (25.92%), while the lowest rates were found on spoons and plates (7.40%). It was discovered that six multidrug resistant isolates were extremely resistant to chloramphenicol and B-lactam antibiotics. Two multi-drug resistant isolates were identified as E. coli and one as Enterobacter spp. by 16S rRNA sequencing. Ampicillin, Amoxicillin, and Penicillin, which are Β-lactam antibiotics, showed noticeably narrower zones (≤ 9.66 mm). Nalidixic acid and chloramphenicol similarly showed little activity, with high variability in certain isolates (SD = 2.35 and 3.09, respectively). Ciprofloxacin, on the other hand, demonstrated high efficacy by producing the largest inhibitory zones (14 to 21.66 mm) with very low standard deviations (e.g., SD = 0.47–0.81). Different isolates had different zone sizes for Meropenem and Nalidixic Acid, with higher standard deviations (SD = 2.45–3.29 and 2.05–3.09, respectively). Ciprofloxacin (77.8%) was the most effective antibiotic, however the antimicrobial resistance profile of E. coli isolates revealed strong resistance to Penicillin (90.89%), Cefotaxime, and Ceftriaxone (82.44%), suggesting possible ESBL development. S. aureus exhibited strong resistance to Ampicillin (79.22%) and Penicillin (80%), but high susceptibility to Amoxicillin (82.1%), Nalidixic Acid (92%), Meropenem (92.33%), and Ciprofloxacin (92%). S. Typhi showed significant resistance to Cefotaxime and Penicillin (85% each), but considerable susceptibility to Ciprofloxacin (91%) and Nalidixic Acid (84.23%). Meropenem (91%) and Ciprofloxacin (90%) were the most effective antibiotics, however Enterobacter species showed very high resistance to the majority of them. P. aeruginosae exhibited intermediate to high resistance, with the most vulnerable strains being Ciprofloxacin (92.66%) and Nalidixic Acid (70.66%).