Isolation, identification, and antibiotic susceptibility pattern of Klebsiella pneumoniae from sputum samples

Abstract

This study was aimed to isolate, identify and determine the antibiotic susceptibility pattern of Klebsiella pneumoniae from sputum samples, as lower respiratory tract infections (LRTIs) remain a major public health concern worldwide, particularly in developing countries like Bangladesh. Clinical sputum samples were collected from patients suspected of lower respiratory tract infections. The samples were cultured on MacConkey agar and further processed using selective media for the isolation of suspected Klebsiella species. Molecular confirmation of the isolates was carried out using Polymerase Chain Reaction (PCR) targeting the species-specific 16S-23S rDNA region. Antibiotic susceptibility testing was performed using the Kirby-Bauer disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. PCR amplification confirmed the presence of Klebsiella pneumoniae in 15 isolates with the appearance of a distinct 130 bp band during agarose gel electrophoresis. The antibiotic susceptibility results revealed a high level of resistance among the isolates. Complete resistance was observed against cefixime (100%), while high resistance was also found for ceftriaxone (71.42%) and tetracycline (64.28%). Moderate resistance was detected for cefepime (53.84%) and meropenem (58.34%). In contrast, comparatively better susceptibility was observed for imipenem (42.85%) and amoxicillin-clavulanic acid (35.71%). Additionally, multidrug resistance was identified in 6 out of 15 confirmed Klebsiella pneumoniae isolates, indicating resistance to at least three different classes of antibiotics. The findings indicate that higher-generation antibiotics, particularly carbapenems, remain more effective against Klebsiella pneumoniae. It also highlights the growing concern of antibiotic resistance in Klebsiella pneumoniae and emphasize the need for continuous surveillance and appropriate antibiotic use for effective infection management.