EN
Escherichia coli bearing β-lactamase resistance genes are a leading cause of developing multi-drug resistance. The aim of this work was to study the molecular characterization and genotypic pattern of β-lactamase resistance genes in Escherichia coli. In total, 203 urine samples of patients who have symptoms of urinary tract infections (UTI) were screened to isolate E. coli and characterize resistance genes. Out of 203 patients, 32 (15.7%) cases were infected with E. coli. All E. coli samples showed a complete resistance against many antibiotics, including tetracycline (100%), rifampin (100%), and gentamycin (100%), but recorded the lowest resistance rate against imipenem (12.5%). Based on the existence of one or more gene of the chuA, yjaA and DNA fragment TSPE4.C2, E. coli is classified under three phylogenetic groups, A, B1, B2, and D. The highest rate of pathogenic E. coli was characterized under phylogenetic groups B2 (37.5%), and D (34.3%). Fifty β-lactamase resistance genes were recovered in this study and some isolates harbored more than one resistance genes. Among them, blaCTX recorded the highest rate, 27 (84.3%), while none of the isolates was detected to bear blaSHV resistance gene. Among five blaCMY genes, three different variants were revealed via sequencing and phylogenetic tree. Two mutations were found in one isolate at position 65 and 566, and three mutations were detected in another isolate at position number 413, 574 and 584, in comparison to a wild type variant. In conclusion, it was revealed that 15.7% cases of urinary tract infections were caused by E. coli. E. coli isolates were completely resistant to many antibiotics, but they were more sensitive to imipenem. Among the fifty β-lactamase resistance genes recovered in this study, blaCTX was the most common gene. There were three variants among blaCMY genes in a single area of study.