Molecular epidemiology of multidrug-resistant uropathogenic Escherichia coli: Virulence, biofilm formation, phylogenetic distribution, and genetic diversity.

BACKGROUND: Multidrug-resistant (MDR) Escherichia coli mediated urinary tract infections (UTIs) are an increasing public health concern, especially in low- and middle-income nations. This study aimed to determine the prevalence, antimicrobial resistance and virulence profile, biofilm forming ability with phylogenetic distribution and genetic diversity of uropathogenic E. coli (UPEC) isolated from UTI patients. METHODS: A total of 718 urine samples were collected from the diagnostic outpatient department of Mymensingh Medical College, Mymensingh, Bangladesh. Samples were analyzed using standard culture technique, and E. coli was identified by MALDI-TOF MS and PCR. Phenotypic antibiotic resistance was detected by the disc diffusion method. Both CRA and CVMP techniques were used to identify the biofilm forming ability. Virulence and resistance genes were identified by PCR. Genetic diversity was studied through phylogrouping, ERIC-PCR, and sequencing of 16 s rRNA gene. RESULT: 125 (17.41%) samples showed significant bacteriuria and were confirmed as UTI cases. E. coli was identified in 38 (30.4%) of these cases and most of the isolates were recovered from females (63.2%) and individuals aged 15-35 years (47.4%). High resistance was observed against meropenem (100%) and amoxicillin (100%), while nitrofurantoin (7.9%) and imipenem (23.7%) had the lowest resistance rate. All of the study isolates were either MDR (66%) or XDR (34%). blaOXA (81.6%), blaCTX-M (55.3%), and qnrA (89.5%) were most prevalent resistance genes. A strong positive correlation (rₛ = 0.719, p < 0.001) was found between resistance gene load and the multiple antibiotic resistance (MAR) index. crl (100%), uidA (100%), and csgA (94.7%) were highly prevalent virulence genes. Approximately 85% of isolates were biofilm producer. Phylogenetic group B2 (36.82%) was predominant and significantly associated with virulence gene carriage and biofilm formation. Furthermore, ERIC PCR revealed a considerable genetic variability among the study isolates. CONCLUSION: These findings highlight the alarming spread of MDR and XDR E. coli strains with high virulence potential, emphasizing the need for continuous monitoring and judicious antibiotic use.