Amir Hasanzadeh - Department of Microbiology, Maragheh University of Medical Sciences, Maragheh, Iran.
Mohammad Reza Pourmand - Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
Gholamreza Pourmand - Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran
Shahram Gooran - Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran

Background: Molecular typing of fluoroquinolone resistant E. coli rectal isolates and its associated infections in patients undergoing prostate biopsyMethods: In this prospective observational cohort study, rectal swabs were collected from 158 men prior to prostate biopsy. The FQR organisms were isolated using selective media, and the antibiotic susceptibility pattern was determined phylogenetic background, prevalence of E. coli sequence type 131 (ST131) and its sub clones (H30 and H30-Rx ST131) were compared in two groups of fluoroquinolone (FQ)-resistant E. coli rectal colonization and clinical isolates. Results: In total, 73 (46.2%) patients had a positive rectal culture for FQ-resistant gram-negative bacteria, the most prevalent isolate of which was E. coli (95.9%). Phylogenetic group B2 was most predominant (70%), followed by A (10%), E (7.14%), C and D (each 4.3%), B1 (2.9%) and F (1.1%). Antibiotic resistance was mainly detected in group B2. The antibiotic susceptibility patterns for the FQR organisms showed high levels of resistance to ampicillin (94%) and trimethoprim-sulfamethoxazole (89.5%), while the resistance to amikacin, fosfomycin and imipenem remained very low (7%, 5.3% and 0% respectively).Antibiotic resistance to several antibiotic was mainly detected in group B2 and with ST131 genotype. Despite the increase in infections among patients colonized with strains of E. coli ST131, its prevalence was almost statistically significant between colonized and infected groups [OR: 3.269, 95% CI: 0.942-11.448; P =.06]. Conclusion: Due to the high prevalence of ST131 and its wide resistance to several antibiotics, health and control measures should be considered to manage this pathogen.

Biopsy, Drug resistance, Infection, Prostate, E. coli ST131