Detection of mrkD and fimH Biofilm Genes and Antibiotic Susceptibility of Uropathogenic Biofilm-Producing Klebsiella pneumoniae in Sana'a City, Yemen
Year: 2026
Type: preprint
Study design: Observational Study
Abstract: Background Urinary tract infections (UTIs) caused by antibiotic-resistant strains of Klebsiella pneumoniae ( K. pneumoniae ) are one of the most important causes of morbidity and health care spending affecting people in Yemen, including young women, children, and the elderly. Biofilm formation has become a major factor among those uropathogenic strains. Objectives This study aimed to investigate the biofilm-forming ability of K. pneumoniae isolated from patients with UTIs, to determine the antibiotic susceptibility of those biofilm producers, and to assess the association between fimbrial virulence genes ( fimH and mrkD ) and biofilm strength. Methods Standard phenotypic microbiological procedures were utilized for the isolation and identification of K. pneumoniae from symptomatic UTI patients. Quantitative biofilm production was determined using the standard tissue culture plate (TCP) assay. Antimicrobial susceptibility testing was performed via the Kirby-Bauer disk diffusion technique in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines. The presence of fimbriae-encoding virulence genes ( fimH and mrkD ) among biofilm-forming isolates was detected using conventional polymerase chain reaction (PCR). Results Out of 241 urine samples processed, K. pneumoniae was verified in 79 cases (32.8%). Biofilm production was phenotypically confirmed in 40 isolates (50.6%), whereas 39 isolates (49.4%) were classified as non-biofilm formers. Among the 40 biofilm-producing strains, 19 (47.5%) displayed a strong biofilm phenotype and 21 (52.5%) exhibited a moderate biofilm phenotype. Regarding resistance patterns, extensively drug-resistant (XDR) phenotypes predominated among biofilm producers at47.50% (n = 19), followed by multidrug-resistant (MDR) phenotypes at 32.5% (n = 13). Pandrug-resistant (PDR) strains represented the most resistant phenotype but were observed at the lowest frequency of 5.0% (n = 2). Complete antibiotic susceptibility was preserved in only 15.0% (n = 6) of biofilm formers. Molecular screening revealed that the mrkD gene was present in 100.0% (n = 40) of the biofilm-producing isolates. The fimH gene was detected in 87.5% (n = 35) of the strains and demonstrated a statistically significant correlation with the strong biofilm phenotype (Prevalence Ratio [PR]: 2.19; 95% Confidence Interval [CI]: 1.5–3.1; p = 0.031). Conclusion The fimbrial virulence genes mrkD and fimH were highly prevalent among biofilm-producing uropathogenic K. pneumoniae isolates in Sana'a City. The presence of fimH was statistically associated with the strong biofilm phenotype; however, the cross-sectional design does not establish causality. The frequent MDR and XDR phenotypes observed among biofilm producers underscore the need for continued antimicrobial-resistance and molecular surveillance.
Source: Research Square
Institution: Sana'a University
Language: English
Subfield: Urology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7204205576