RESUMEN
The present study was carried out to evaluate the prevalence of antibiotic resistance genes in Escherichia coli isolates from HIV and thalassemia patients and to determine the phylogenetic group distribution and to genotype the isolates in southeastern Iran. This cross-sectional study was performed in E. coli isolates taken from fecal and urine samples of 43 HIV and 62 thalassemia patients. The E. coli isolates were examined for 13 antibiotic resistance genes and determine the phylogroups. The Rep-PCR DNA fingerprinting method was utilized to determine the genotype of the isolates. Among the 105 E. coli isolates, 66.7% isolates were positive for qnrS, 55.2% for dhfrI, 40.9% for sulI, 33.3% for sulII and 31.4% for blaTEM genes. A blaCTX-M-15 gene was detected in 20.9% isolates, aac(3)-I in 14.3% isolates and aadA in 12.4% isolates, whereas blaSHV and qnrB genes were identified in 10.5% and 8.6% isolates, respectively. Out of the isolates, only 2.8% isolates possessed the blaOXA-1 gene, and no IMP and VIM genes were detected. The significant phylogroup was A (37.2%), B2 (15.3%), B1 and unknown (each 14.3%), D (13.4%) and C, F and clade I (each 2%). Phylogroup A accounted for the highest antibiotic resistance. The results of Rep-PCR indicated that the isolates were closely related. These results showed a high prevalence of genes encoding antibiotic resistance in the E. coli isolates. The majority of E. coli isolates distributed among phylogroup A, whereas positive isolates for antibiotic resistance genes were disseminated among various phylogroups (A, B2, and D).