Study of Biofilm, Virulence Genes, and Risk Factors in Urinary Catheter-Associated Escherichia coli Infections

Abstract

Background: Catheter-associated urinary tract infections (CAUTIs) are prevalent among intensive care unit (ICU) patients and pose significant health risks. The causative agent, Escherichia coli, is commonly associated with these infections. Objectives: The primary objective of our study was to evaluate various risk factors associated with CAUTIs. Additionally, we investigated the capacity of E. coli to form biofilms and the presence of virulence genes in these infections. Methods: We conducted a prospective study involving 204 patients admitted to ICUs with indwelling urinary catheters who subsequently developed CAUTIs. The isolated pathogen in all cases was E. coli. We subjected the isolated E. coli strains to microbiological analyses, including biofilm formation assays and polymerase chain reaction (PCR) for detecting virulence genes (pap-C, fim-H, sfa, afa, hylA, and cnf1). Results: Our findings revealed that 111 out of 204 isolated E. coli strains (54.4%) could form biofilms in vitro. Among the detected virulence genes, fim-H was the most frequently observed (32.4%), followed by pap-C (14.2%), sfa (12.3%), and afa1 (11.3%). The least frequently detected genes were cnf1 (3.9%) and hylA (2.5%). Notably, there was a significant association between the presence of fim-H, pap-C, afa1, and hylA genes and the ability of E. coli to form biofilms (P = 0.001, P = 0.001, P = 0.04, P = 0.046, respectively). Regarding the timing of CAUTIs, most cases occurred 7 - 10 days after catheter insertion (48.53%), followed by 3 - 6 days after insertion (45.59%). The least frequent occurrence was after 10 days from catheter insertion (5.86%). Early presence of CAUTIs (within 3 - 6 days) was significantly associated with diabetes mellitus (DM) and post-operative complications (both with P = 0.046). Furthermore, we observed a significant increase in the presence of the cnf1 gene in cases of early CAUTIs (3 - 6 days after catheter insertion, P = 0.001). Conclusions: Our study highlights the importance of understanding the risk factors, virulence genes, and biofilm formation capacity in E. coli-related CAUTIs. These findings may guide preventive strategies and improve patient outcomes.