Molecular detection and risk factors of carbapenemase -encoding gene among the Gram-negative uropathogens associated with catheter-associated urinary tract infection

Carbapenem-resistant Gram-negative bacteria frequently cause catheter-associated urinary tract infections (CA-UTIs). The objectives of this study included investigating prevalence, drug-resistance mechanisms, and risk factors associated with the infections caused by carbapenemase genes harboring uropathogens causing CA-UTI. This cross-sectional study was conducted from June to December 2024 in Karachi. A total of 308 Gram-negative isolates from urine sample of CA-UTI patients were analyzed for antimicrobial susceptibility testing, and for the detection of bla NDM , bla OXA-48 bla KPC, bla IMP and bla VIM . The clinical factors related to gene carriage were determined by chi-square and binary logistic regression, with p ≤ 0.05 considered statistically significant. Escherichia coli (134/308; 43.5%) and Klebsiella pneumoniae (96/308; 31.2%) were the most common isolates. The resistance rates were higher against ceftriaxone (244/308; 79.2%), ciprofloxacin (238/308; 77.3%), but lower to meropenem (104/308; 33.8%) and imipenem (96/308; 31.2%). Out of the 104 carbapenem-resistant (CR) gram-negative isolates, bla NDM was the most prevalent (66/104; 63.5%), followed by bla OXA-48 (40/104; 38.5%). However, it varied among the isolates as bla NDM was more prevalent in K. pneumoniae (31/48; 64.6%) and bla OXA-48 was more predominant in CR- P. aeruginosa (4/10; 40%). While, co-existence of both genes was found in 12/104 of the isolates (11.5%). Independent predictors of gene positivity were ICU admission, previous exposure to antibiotics, and catheterization longer than seven days. In CAUTI, E. coli was the predominant uropathogen and bla NDM was the most prevalent gene in carbapenem-resistant Enterobacterales. bla OXA−48 was more prevalent in CR- P. aeruginosa .