Background and Aims:
Klebsiella pneumoniae is a major cause of hospital-acquired infections, where
biofilm formation and quinolone resistance complicate treatment outcomes. This research examined the occurrence of
biofilm formation, plasmid-mediated quinolone resistance (PMQR) determinants, and chromosomal alterations among clinical K. pneumoniae isolates.
Materials and Methods: In this cross-sectional investigation, ۱۲۰ K. pneumoniae were obtained. Antimicrobial susceptibility and
biofilm formation tests carried out using disk diffusion and microtiter plate methods, respectively. Minimum inhibitory concentration (MIC) was determined by the agar dilution approach. Polymerase chain reaction (PCR) and DNA sequencing were carried out to identify resistance- and biofilm-related genes, along with mutations in the gyrA and parC genes. Statistical analysis was performed using SPSS ۲۲.۰, and the association between
biofilm formation and FQ resistance was evaluated with Fisher’s exact test (p<۰.۰۵ considered significant).
Results: The highest resistance was observed against ampicillin (۷۷.۵%, ۹۳/۱۲۰). Biofilm production was observed in ۶۹.۲% (n; ۸۳/۱۲۰). Resistance to ciprofloxacin was seen in ۵۶.۷% isolates, and PCR revealed frequent presence of gyrA, parC, qnrS, aac(۶′)-Ib-cr, qepA, oqxA, and oqxB genes, with common mutations S۸۳I and D۸۷N in gyrA and S۸۰I and E۸۴V in parC. Biofilm-producing isolates had significantly higher resistance to ampicillin (p=۰.۰۰۱>), imipenem (p=۰.۰۳۷), gentamicin (p=۰.۰۴۵), and ceftazidime (p= ۰.۰۰۳), and fluoroquinolone resistance genes (qepA, oqxB) were more prevalent among them.
Conclusion: This investigation revealed a considerable frequency of PMQR genes and chromosomal alterations in quinolone-resistant K. pneumoniae isolates, highlighting a strong association between
biofilm formation and antimicrobial resistance. The outcomes underscore the genetic mechanisms underlying resistance and the difficulties in controlling infections triggered by these strains.