Multidrug Resistance and Molecular Characterization of Klebsiella spp. Isolated from the Cloacal Samples of Broiler Chickens in Bangladesh

Abstract

Klebsiella spp. poses a significant zoonotic threat, capable of direct and indirect transmission from poultry farms to humans, resulting in severe conditions such as pneumonia, bloodstream infection, enteric fever, meningitis and urinary tract infections. The escalating use of antibiotics in the poultry industry is contributing to the rise of multidrug-resistant (MDR) microorganisms. Thus, a study was undertaken to comprehend the multidrug resistance and virulence gene profile of Klebsiella spp. isolated from poultry cloacal samples sourced from local markets of North Dhaka, Bangladesh. Following aseptic collection, the samples were transported to the laboratory for pure culture isolation. Employing standard microbiological methods such as mucoid colony characteristic, Gram-negative rod-shaped bacteria, biochemical tests and lactose fermentation in selective media, the isolated colonies were presumptively identified. Subsequently, an antibiotic susceptibility test, utilizing the disk diffusion assay, was conducted to assess drug sensitivity in these isolates. A PCR assay was performed to determine the presence or absence of KPC gene of Klebsiella. Among the isolates, ten colonies were identified as Klebsiella spp. based on the colony characteristics, Gram staining, biochemical tests and growth on selective media. Notably, eight isolates (excluding 2 and 4) were incapable of producing indole from tryptophan, indicating the presence of two different types of species. All isolates exhibited resistance to at least three antibiotics, namely ceftazidime, ampicillin and cefoxitin. Isolate 2 and 5 were demonstrated additional resistance to azithromycin, while isolate 9 and 10 exhibited further resistance to streptomycin and doxycycline. Molecular analysis indicated that 40% of these isolates harbor KPC virulent gene (880bp), with the most multidrug resistant isolate 9 and 10 possessing this gene. This study is pivotal for assessing the prevalence of virulent and MDR Klebsiella spp. in chicken cloacal samples, providing insights into shedding and transmission risk on soil and water environment, as well as to humans.