Lytic Bacteriophages Targeting Carbapenem-Resistant Klebsiella Pneumoniae Isolated in a Resource-Limited Zambian Laboratory

2. Abstract Klebsiella pneumoniae is a major cause of healthcare-associated and community-acquired infections, increasingly complicated by multidrug resistance (MDR) and carbapenem-resistant K. pneumoniae (CRKp). Phage-based approaches are attractive in such settings, but most reported work relies on infrastructure and expertise that are not widely available in low-resource laboratories. Here we describe the isolation and preliminary characterisation of two lytic K. pneumoniae phages, Zm_01 and Zm_02, from hospital sewer sludge in Lusaka, Zambia, using only routine microbiology equipment and simple adaptations of standard protocols. Clinical K. pneumoniae isolates, including MDR strains, were used for enrichment, double-agar overlay plaque assays, host-range screening, and determination of Efficiency of Plating (EOP). Zm_01, isolated on a non-MDR but hypermucoviscous host, produced small, clear plaques and exhibited efficient plating on several MDR isolates, with EOP values higher on some MDR strains than on its original host. Zm_02, isolated on an MDR strain, formed large, clear plaques with halos, consistent with capsule-degrading activity. All work was performed without access to specialised equipment, such as a spectrophotometer, a shaker incubator, or standard imaging equipment. These findings demonstrate that discovery and basic phenotypic characterisation of therapeutically relevant K. pneumoniae phages are feasible in low-resource settings and provide a practical workflow that can underpin future functional and genomic studies, as well as the development of locally tailored phage-based interventions against MDR and CRKp infections.