The Pool of Beta-lactamase Present in Extended Drug Resistant Klebsiella pneumoniae Isolated from Clinical Settings in Dhaka, Bangladesh.

Recently bacterial infections caused by antibiotic resistant bacteria are becoming a threat to the health care system of many countries. Extensively-drug-resistant (XDR) Klebsiella pneumoniae are resistant to almost all classes of antibiotics and only a few are for clinical use. Recent emergence, worldwide dissemination and clinical impact of carbapenemase positive isolates persuade us to characterize the clinical K. pneumoniae isolates. We tested 647 K. pneumoniae that was isolated from different specimens of hospitalized patients in Dhaka, Bangladesh. Various phenotypic characterization, plasmid profiling and PCR assays followed by sequencing were performed. Round the year, 4.33% (n=28) K. pneumoniae isolates were found as XDR in addition to carbapenem resistant. Among the XDR isolates, 82.0% (n=23) showed Metallo-beta-lactamase (MBL) phenotype. Only two isolates showed MBL with KPC (K. pneumoniae carbapenemase) phenotype. By double disc synergy test, 12 isolates (43.0%) showed extended-spectrum beta-lactamase (ESBL) phenotype in addition. Among the isolates, 60.0% (n=17) were blaTEM positive, 82.0% (n=23) were blaSHV positive and 46.0% (n=13) were blaOXA positive determined by multiplex PCR. BlaCTX-M were present in 43.0% (n=12) isolates, which were of type-15 as revealed by sequencing. More than 60.0% (n=17) isolates were positive for blaNDM-1. Multiple genes coexisted in nearly all isolates. None of those were found to carry blaVIM or blaKPC. Twenty-six isolates were found to be strong biofilm former. Among the isolates, 16 harbored multiple plasmids ranging from 19 to 91 KDa; however, correlation between plasmid profile and antibiotic resistance pattern was not evident. Prevalence of carbapenem resistant and ESBL isolates have been previously reported in Bangladesh. Therefore, this study will expand our knowledge about XDR disseminated in Bangladesh and could assist in future therapeutic management.