Virulence Factor Profiles of Uropathogenic Escherichia coli in Community-Acquired and Health-Care Associated Urinary Tract Infections

Open Access

Abstract

Background: Urinary tract infections are among the most common bacterial infections worldwide, with most cases caused by a single bacterium, uropathogenic Escherichia coli (E. coli). The study aimed to compare virulence factor patterns and antibiotic resistance profiles of Uropathogenic E. coli (UPEC) isolates from community-acquired and healthcare-associated UTIs. Methods & Materials: This cross-sectional analytical study was carried out at Sir Salimullah Medical College, Dhaka, Bangladesh from January to December 2020, including a total of 164 urine specimens collected from patients with clinically suspected UTI. Group I consisted of 82 outpatients with CA-UTI, and Group II consisted of 82 inpatients with HA-UTI (catheterized and non-catheterized subgroups). The E. coli isolates were tested for virulence factors such as haemolysin production, haemagglutination (mannose-sensitive and mannose-resistant), serum resistance, gelatinase production, and fimH gene detection by PCR. Antimicrobial susceptibility test was performed by the Kirby-Bauer disc diffusion method. Results: E. coli was isolated from 65.9% of CA-UTI cases compared to 46.3% of HA-UTI cases. Virulence factors were significantly more prevalent in CA-UTI isolates: haemolysin production (22% vs 3.7%), serum resistance (20.7% vs 6.1%), mannose-resistant haemagglutination (13.4% vs 2.4%), and fimH gene (56.1% vs 40.2%). Multiple virulence factors (≥3 factors) were observed in 25.6% of CA-UTI isolates versus 7.3% in HA-UTI. Carbapenems demonstrated the highest sensitivity rates (meropenem 61% and imipenem 58.5% in CA-UTI), while high resistance was noted to cephalosporins and amoxiclav. Conclusion: Community-acquired strains of UPEC showed a significantly higher expression of virulence factors than their healthcare-associated counterparts, thus indicating different pathogenic mechanisms. The correlation between virulence profiles and the source of infection may have implications for both therapeutic strategies and infection control measures.