Background

Klebsiella pneumoniae is a major cause of urinary tract infections (UTIs) and is increasingly associated with extended-spectrum beta-lactamase (ESBL) production and biofilm formation, both of which complicate treatment and contribute to antimicrobial resistance. This study aimed to determine the prevalence of ESBL production and biofilm formation among K. pneumoniae urinary isolates in a tertiary care teaching hospital and to evaluate their association with multidrug resistance and clinical risk factors.

Methods

A cross-sectional study was conducted on 294 non-duplicate K. pneumoniae isolates recovered from urinary samples. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disc diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. ESBL production was confirmed using the combined disc method, while biofilm formation was assessed using the microtiter plate assay. Statistical associations were analyzed using the Chi-square test, and a p-value of less than 0.05 was considered statistically significant.

Results

ESBL production was detected in 176 (59.9%) isolates, while 214 (72.8%) demonstrated biofilm-forming ability. Multidrug resistance (MDR) was observed in 158 (53.7%) isolates. A significant association was found between ESBL production and biofilm formation (p < 0.001). Inpatient status, ICU admission, urinary catheterization, diabetes mellitus, and recurrent urinary tract infection were significantly associated with ESBL positivity. Resistance to carbapenems remained relatively low, with resistance rates of 8.2% for imipenem and 9.5% for meropenem.

Conclusion

The coexistence of ESBL production, multidrug resistance, and biofilm formation among K. pneumoniae urinary isolates represents a major therapeutic challenge. The strong association between resistance mechanisms and biofilm-forming ability highlights the need for continuous antimicrobial surveillance, effective infection control practices, and robust antimicrobial stewardship programs. Early detection of ESBL-producing strains and appropriate antibiotic management are essential to limit the spread of resistant organisms and improve clinical outcomes.