Prevalence of ESBLs and Biofilm Formation in Escherichia coli Isolated from Urinary Tract Infection in Isfahan, Iran

Abstract

Backgrounds: Uropathogenic Escherichia coli is a Gram-negative bacillus that is the most common cause of urinary tract infection. E. coli has the ability to produce biofilm as an important virulence factor. Due to the lack of sufficient information about ESBL resistance genes in this geographical area, this study aimed to investigate the prevalence of ESBLs in E. coli isolates to increase our knowledge about the role of these genes and biofilm formation in inducing resistance. Materials & Methods: 139 E. coli strains were isolated from urine samples. Antibiotic susceptibility testing was performed for the isolates by disk diffusion method. ESBL production was confirmed using double-disk synergy test. Molecular detection of ESBL genes was performed using PCR. Biofilm formation assay was performed by microtiter plate method. Findings: The most effective antibiotic against this bacterium was nitrofurantoin. Multidrug resistance was observed in 119 (85.6) isolates. ESBL phenotype was detected in 93 (66.9) isolates. The PCR test results showed that blaCTX, blaVEB, and blaTEM were positive in 45 (32.4), 87 (62.6), and 10 (7.2) isolates, respectively. The biofilm formation assay results revealed that 65 (46.8), 58 (41.7), 10 (7.2), and six (4.3) isolates were non-, weak, moderate, and strong biofilm producers, respectively. Conclusions: The high prevalence of ESBL genes is a public health concern in this region because they could be transmitted to other susceptible bacteria and induce resistance. This study showed that biofilm production could increase antibiotic resistance. @ 2022, TMU Press.