molecular evaluation of aminoglycoside resistance and biofilm formation potential in escherichia coli isolates collected from hospitalized patients

Background: resistance to antibiotics and the ability to develop biofilms, two main virulence determinants of escherichia coli, play a crucial role in the persistence of infections. objectives: the aim of this study was to evaluate aminoglycoside resistance and biofilm formation potential in e. coliisolates collected from hospitalized patients in the southwest of iran. methods: a total of 70 e. coliclinical isolates from different specimens were collected from ahvaz teaching hospitals affiliated with ahvaz jundishapur university of medical sciences. all the isolates were identified as e. coliusing conventional microbiological tests. susceptibility to antibiotics was determined using the kirby–bauer disk diffusion method. biofilm formation was assessed using the microtiter plate method. finally, pcr was conducted to detect virulence gene determinants, including fimbrial genes, aminoglycoside modifying enzymes (ames), and 16s rrna methylase (rmtase) genes. results: among aminoglycoside antibiotics, e. coliisolates showed the highest and lowest resistance rates to tobramycin (tob; 51.4%) and gentamicin (gen; 24.2%), respectively. simultaneous resistance to gen, amikacin, and tob was observed in 28.5% of the isolates, representing the most common antibiotic resistance pattern. the prevalence of strong biofilm producers was higher in the extensively drug-resistant (xdr) phenotype group compared to the multiple drug-resistant (mdr) group (76.1% vs. 23.8%). among the 36 isolates resistant to at least one of the aminoglycoside antibiotics, 36.1% had ame-related genes, either alone or in various combinations. most isolates harboring ame genes were also positive for the presence of biofilm-related genes, including ecpaand fima. conclusions: the most frequent ame-related genes were ant(2”)-ia and aph(3’)-ia, followed by aac(3’)-iia. the findings of the present study provide probable evidence that gen is an effective aminoglycoside against biofilm-producing and antibiotic-resistant e. coliisolates.