Prevalence and Molecular Detection of Virulence Genes among Multidrug-Resistant Escherichia coli from Human Clinical Samples and Poultry in Duhok City, Iraq

Abstract

Abstract Background: Extended-spectrum beta-lactamase (ESBL)-producing, carbapenem-resistant Escherichia coli has increased virulence and multidrug resistance (MDR). Objectives: This study was designed to ascertain the frequency of some virulence factor genes, antibiotic susceptibility patterns, ESBLs, and MDR, focused on colistin-resistant E. coli strains of human and animal origin in Duhok city, Iraq. Materials and Methods: Between December 2020 and April 2021, a total of 150 E. coli isolates (110 from human clinical specimens and 40 from poultry cloacal swabs) were included in this study. The isolates underwent screening for antibiotic susceptibility, MDR, ESBL, and molecular detection of four virulence genes (fimA, cnfL, crL, and hlyA) was conducted using the polymerase chain reaction. Results: Urine specimens (77.2%) compared to blood, wound, vaginal swab, sputum, and semen from outpatients (71.8%). All strains from humans and poultry showed high resistance to ampicillin (86%–97%), ceftriaxone (74%–47%), tetracycline (72%–85%), ciprofloxacin (48%–97%), and colistin (17%–12%). The lowest levels of resistance were found for carbapenems (4%–4%), and the MDR for the isolates was 63%–93%. Apart from carbapenems, colistin-resistant isolates, especially those from poultry, exhibited significant resistance to other antibiotics, and 57% of these isolates being ESBL producers. Three virulence genes (fimA, cnfL, and crL) were highly prevalent (92%) in human isolates, with the crL gene being predominant (100%). Among poultry isolates, fimA was more prevalent (94%) while crL was less common (6%). Conclusion: The predominance of isolates of colistin-resistant poultry origin and the virulence of isolates of human E. coli origin indicate that both strains are currently experiencing an increase in antibiotic resistance.