Distribution of mrk genes among uopathogenic Klebsiella pneumoniae.

The mrk operon gene clusters encode type 3 fimbriae, involving in biofilm formation. Hence, we aimed to find out the distribution of mrk genes among uropathogenic Klebsiella pneumoniae (UPKP) strains. Moreover, mrk genes, hypermucoviscosity (HMV) characteristic and antimicrobial resistance (AMR) patterns and profiles were successfully, provided. From August 2023 to January 2024, 104 positive urine samples were collected. Standard microbiological and biochemical tests were employed to confirm the UPKP strains. Kirby-Bauer disc diffusion method was recruited to conduct antimicrobial susceptibility test (AST). The HMV characteristic in UPKP isolates was assessed using the string test. Finally, multiplex polymerase chain reaction (mPCR) was used to identify mrk genes distribution. Chi-square (χ2) and Fisher's exact tests were utilized for statistical analysis. The mrk gene distribution varied among the UPKP isolates comprising mrkA (1.92%), mrkB (0.00%), mrkC (5.77%), mrkD (23.08%), mrkE (37.50%), and mrkF (83.65%). No mrk genes were detected among 13.46% (14/104) of UPKP isolates. The most common mrk gene patterns involved mrkF (32.70%), mrkE-mrkF (25.00%), and mrkD-mrkF (11.54%). In addition, the isolates exhibited diverse AMR profiles and phenotypes including: 65 multi-drug resistant (MDR) strains (nine groups, 42 patterns), 13 extensively drug-resistant (XDR) strains (nine patterns), nine pan drug-resistant (PDR) strains, 23 ESBL producers, and nine HMV isolates. None of the HMV strains displayed XDR, PDR, or ESBL phenotypes, suggesting limited horizontal gene transfer (HGT). Detailed analysis of mrk genes and AMR characteristics in UPKP, provides essential information for selecting effective prevention protocols and treatments for urinary tract infections (UTIs) and combating AMR.