Quinolone Resistance in Biofilm-Forming Klebsiella pneumoniae-Related Catheter-Associated Urinary Tract Infections: A Neglected Problem

Background: Klebsiella pneumoniae is a bacterium that commonly causes urinary tract infections (UTIs) in hospital settings. The widespread and improper usage of quinolones has increased the resistance rates against these broad-spectrum antibiotics. Objectives: This study aimed to examine the connection between the ability to form biofilms and fluoroquinolone resistance in K. pneumoniae isolated from catheter-associated UTIs. Methods: A total of 110 nonduplicative K. pneumoniae-related catheter-associated UTIs were isolated from three large educational hospitals in Babol, north of Iran. The minimal inhibitory concentration (MIC) of ciprofloxacin was calculated for each detected isolate using the agar dilution procedure. Biofilm production was investigated by a 96-well flat-bottom microtiter plate. The prevalence of gyrA, parC, qnrA, qnrS, acc (6')-Ib-cr, qepA, qnrB, oqxA, and oqxB genes was evaluated using polymerase chain reaction (PCR). Results: Overall, 28.2% of the strains were resistant to imipenem and considered carbapenem-resistant K. pneumoniae (CRKp). Ciprofloxacin resistance was observed in 66.4%. Moreover, 70% of the isolates produced biofilm. Biofilm production was significantly higher in ciprofloxacin-resistant compared to ciprofloxacin-susceptible strains (P-value < 0.05). Molecular distribution of resistance genes in the 68-fluoroquinolone resistance-Kp strains showed that the prevalence of gyrA, parC, qnrA, qnrS, acc (6')-Ib-cr, qepA, qnrB, oqxA, and oqxB genes was 39.7%, 42.6%, 5.9%, 54.4%, 69.1%, 94.1%, 41.2%, 69.1%, and 83.8%, respectively. Conclusions: Our study highlights the high prevalence of plasmid-mediated quinolone resistance genes in clinical samples of K. pneumoniae in the studied region, which is alarming given the possibility of the spread of these pathogens and the few treatments available for infections brought on by multidrug-resistant strains. Moreover, the study characterizes particular mutations in the parC and gyrA genes that cause quinolone resistance.