Prevalence and co-resistance network analysis of multidrug-resistant Escherichia coli isolates from urinary tract infections, a cross-sectional study

Multidrug-resistant (MDR) strains play a major role in the antimicrobial resistance (AMR) crisis. Misuse of antibiotics has caused Escherichia coli ( E. coli) strains to evolve and resist antibiotics, leading to their ineffectiveness in treating urinary tract infections (UTIs). This has also led to the emergence of strains producing extended-spectrum β-lactamase (ESBL). This study aims to understand the resistance patterns in E. coli urine isolates collected over a period of 6 months. A cross-sectional study was conducted at a diagnostic laboratory in Chennai from October 2023 to March 2024, analysing 1356 urine E. coli isolates. The VITEK2 automated system (BioMérieux, Marcy-l’Étoile, France) AST card N-235 was used to assess the antibiotic susceptibility pattern of the isolates. Statistical analysis was done using GraphPad Prism. Additionally, computational analysis was performed using Python to generate co-resistance network, in which nodes represented individual antibiotics and edge weights is proportional to the number of isolates exhibiting simultaneous resistance to antibiotics. Logistic regression was used to evaluate the correlation between patient age and the likelihood of resistance. The analysis revealed that nalidixic acid, ampicillin and ticarcillin showed high resistance rates. 70.5% of the isolates were MDR, and a higher number of cases were seen among females (75.5%). ESBL production was detected in 35.3% of the isolates. Co-resistance network analysis revealed an interconnected resistance network around nalidixic acid, ampicillin, and ticarcillin. Logistic regression analysis indicated a positive correlation between age and resistance to fluoroquinolone antibiotics. In summary, our study findings highlight high incidence of MDR E. coli causing UTI. Significant age-associated increase in resistance may be due to increased antibiotic exposure and recurrent infections in older age groups. These results indicate that tackling MDR-UTIs will require efforts, including wise use of antibiotics, enhanced surveillance, infection control measures and global collaboration in resistance monitoring.