Molecular basis of quinolone resistance in clinical isolates of Klebsiella pneumoniae from Pakistan

Antibiotic resistant Klebsiella pneumoniae, is associated with various nosocomial infections that are difficult to treat. This study is designed to find out the patterns of resistance against commonly used antibiotics in K. pneumoniae clinical isolates with special attention to fluoroquinolones. A total number of 200 K. pneumoniae clinical isolates collected from various tertiary care hospitals of Punjab, Pakistan for a span of 1 year were investigated. Isolates were identified biochemically and genetically using VITEK (R) system and species-specific PCR, respectively. Antibiogram of isolates was studied by using disc diffusion and broth micro-dilution assays. Highest infection of K. pneumoniae detected in urinary tract (43%) followed by respiratory tract (25.5%). Most of the isolates displayed strong resistance against ampicillin, cefotetan, tazobactam, cefuroxime, cefixime, ceftriaxone, ampicillin-sulbactam imipenem, meropenem, ciprofloxacin and moxifloxacin, while sensetive to cefotaxime. Chromosoaml mutation was deteted in gyrA gene, gyrA harbors a strong mutation which provides resistance against ciprofloxacin by substituting Ser83 -> Ile. However, no mutation was detected in gyrB gene. Moreover, qnrB 1 plasmid born resistant gene was only detected among qnrA, qnrB and qnrS. The story depicts an alarming situation of antibiotic resistance among K. pneumoniae associated with various nosocomial infections.