Phenotypic and molecular characterization of cefotaxime-resistant Klebsiella pneumoniae from chicken litter of selected farms in Uganda

Abstract

OBJECTIVE: Poultry farm environments are recognized as reservoirs of antimicrobial-resistant bacteria with implications for One Health. Klebsiella pneumoniae, a clinically important opportunistic pathogen, has shown rising resistance to third-generation cephalosporins, including cefotaxime. However, data on cefotaxime-resistant K. pneumoniae (CRKP) in poultry environments in Uganda remain limited. This study determined the proportion and characterized CRKP isolated from chicken farm litter in central Uganda. A retrospective study was conducted using 98 archived environmental litter samples collected from 20 commercial broiler farms in Wakiso District, Uganda. Selective culture and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used to identify CRKP. Antimicrobial susceptibility testing was performed using the disk diffusion method. Phenotypic assays assessed virulence-associated traits, and PCR was used to detect the ESBL-associated blaCTX-M-15 gene. RESULT: CRKP was detected in 32.7% (32/98) of samples. All isolates were multidrug resistant (MDR), with universal resistance to tetracycline, trimethoprim-sulfamethoxazole, and ampicillin, while no resistance to imipenem was observed. Biofilm formation and hyper mucoviscosity were detected in 21.9% and 18.8% of isolates, respectively. Although all isolates expressed an ESBL phenotype, blaCTX-M-15 was detected in only 18.8%. Poultry environments are reservoirs of MDR-CRKP, revealing the need for strengthened antimicrobial stewardship and environmental AMR surveillance.