frequency of extended-spectrum beta-lactamases-producing escherichia coli among out- and in-patients in rafsanjan city, iran

Background: the frequency of extended-spectrum beta-lactamase (esbl)-producing escherichia coli strains among clinical isolates has been steadily increasing, leading to limited treatment options. objectives: this study aimed to assess the antibiotic sensitivity of e. coli and the frequency of esbl isolates among both out-patients and in-patients. methods: a total of 390 e. coli isolates were received at the ali-ebn-e-abitaleb hospital laboratory in rafsanjan. the antibiogram, as well as the phenotypic and genotypic detection of esbl isolates, were conducted using kirby-bauer, combination disk confirmatory, and polymerase chain reaction tests, respectively. results: of all the e. coli isolates, 45.6% exhibited esbl production. among these isolates, 46.1% were obtained from hospital wards, while 42.5% were from outpatients. meropenem and imipenem displayed sensitivities of 97.2% and 93.3%, respectively, whereas amikacin and nitrofurantoin showed sensitivities of 89.7% and 85.6%, respectively, for all isolates. notably, ceftriaxone, cefotaxime, cefixime, ampicillin, co-trimoxazole, andnalidixic acid demonstrated high resistance rates, surpassing 50%. esbl-producing isolates were more frequently observed in blood samples (65%) and wounds (60%) compared to other tested isolates. approximately 8.6% of isolates carried a single type of esbl gene, while 38.5% carried multiple esbl genes. conclusions: the data indicate a prevalence of esbl-producing e. coli isolates among both out-patients and in-patients, with some of them acquiring two or three types of esbl enzymes. as a result, their ability to hydrolyze antibiotics has increased, leading to their higher occurrence in clinical samples.