Asian Journal of Microbiology and Biotechnology

Background: Klebsiella species are opportunistic Gram-negative pathogens and important causes of nosocomial infections, while multidrug-resistant (MDR) strains are an increasing global public health concern. This study determined the prevalence and phenotypic antibiotic susceptibility profile of Klebsiella species isolated from clinical samples at Ladoke Akintola University of Technology (LAUTECH) Teaching Hospital, Ogbomoso, Nigeria.

Methods: In this cross-sectional study conducted between January and March 2022, 65 Klebsiella isolates recovered from clinical specimens (urine, wound swab, sputum, eye swab, bone biopsy, and ear swab) were identified using standard cultural, morphological, and biochemical methods. Antibiotic susceptibility to 14 antibiotics across eight classes was determined by the Kirby-Bauer disc diffusion method and interpreted using CLSI M100 (2022) zone-diameter breakpoints. Isolates resistant to at least one agent in three or more antimicrobial categories were classified as multidrug-resistant (MDR). Data were analysed using SPSS version 19.0; associations between categorical variables were assessed with the Pearson chi-square test, supplemented by Fisher's exact test where expected cell counts were small (α = 0.05).

Results: Klebsiella pneumoniae was the most frequently isolated species (23/65, 35.4%), followed by K. oxytoca (33.8%), K. aerogenes (23.1%), K. rhinoscleromatis (4.6%), and K. ozaenae (3.1%). Isolates showed the highest resistance to ampicillin (72.3%) and amoxicillin (43.1%), and the highest susceptibility to imipenem (83.1%) and gentamicin (64.6%); however, 23.1% of isolates were resistant to meropenem. Overall, 13 of 65 isolates (20.0%) met the criteria for multidrug resistance. MDR status was not significantly associated with species, specimen type, age group, or gender (p > 0.05). Species distribution did not differ by age or gender but differed significantly by specimen type (Fisher's exact p = 0.005), with K. oxytoca predominating in urine.

Conclusion: One in five Klebsiella isolates was multidrug-resistant, with the highest resistance to penicillins and cephalosporins. Imipenem and the aminoglycosides retained the highest in vitro activity, although the meropenem resistance observed warrants confirmation and monitoring. Routine phenotypic susceptibility surveillance, antibiotic stewardship, and confirmatory molecular characterisation of species identity and resistance determinants are recommended.