Molecular Determinants of Antibiotic Resistance in Klebsiella pneumoniae Isolates from Septicaemia Cases in ICU Patients

Background: Klebsiella pneumoniae is a prominent pathogen linked to septicemia, especially among patients in intensive care units (ICUs), where it poses a significant risk due to its growing antimicrobial resistance. In Bangladesh, there is a lack of updated, localized data regarding its resistance trends, particularly in critical care environments. Methods: This cross-sectional study was conducted over 03 years (July 2021 – June 2024) in the ICUs of two tertiary hospitals in Dhaka. Blood samples from 301 patients with suspected septicemia were analyzed using automated culture and identification systems. Antimicrobial susceptibility testing was performed using the disc diffusion method, following the Clinical and Laboratory Standards Institute (CLSI) guidelines. Additionally, 11 multidrug-resistant K. pneumoniae isolates were subjected to PCR (Polymerase Chain Reaction) to detect specific resistance genes. Results: Out of the 301 septicemic cases, 64.8% were male. Gram-negative bacteria dominated the isolates, with K. pneumoniae being the second most common organism (25.2%). These isolates showed high resistance to multiple antibiotics, including ceftazidime (84.2%), cotrimoxazole (80.3%), and ceftriaxone (75.0%). Notably, 48.7% of isolates were resistant to meropenem. However, colistin (5.3%) and tigecycline (1.3%) remained relatively effective. Molecular analysis revealed that all selected K. pneumoniae strains carried key resistance genes such as blaCTX-M, blaNDM-1, blaOXA-48, blaSHV, blaTEM, and mphA. The blaCTX-M-15 gene was also highly prevalent (90.91%), where as blaKPC and blaCTX-M-9 were not detected.