WGS of a lytic phage targeting biofilm-forming carbapenem-resistant Klebsiella pneumoniae prevalent in a tertiary healthcare setup.

Carbapenem-resistant Enterobacteriaceae (CRE) are listed as a priority-one critical pathogen category by the WHO because of their abysmal treatment outcomes owing to antibiotic inefficiency. Among CRE, Klebsiella pneumoniae is prevalent in acquiring resistance genes and withstanding the last-resort drugs. Additionally, its ability to form robust biofilms further exacerbates the treatment challenges. The escalating resistance and recalcitrance of biofilm-residing bacteria against standard antibiotic treatments demand an alternative to antibiotics. Phages, being nature-tailored, are a never-ending arsenal against the bacteria because of their capacity to lyse bacteria rapidly and co-evolve with bacteria. In our study, we isolated K. pneumoniae from patients at Madras Medical Mission Hospital (MMMH), India, and assessed their antibiogram profiles, presence of carbapenemase genes, and biofilm-forming abilities. 100 % of the strains were extended-spectrum beta-lactamase producing, multidrug-resistant (ESBL-MDR), with 95 % harbouring carbapenemase genes. Among the isolates, 65 % were strong biofilm formers, and the rest were moderate. Further, we isolated a bacteriophage, SAKp11, from the hospital sewage, which was able to lyse 62 out of 167 clinical isolates and successfully reduced 99.99 % viable bacterial cells of the 24-h-old biofilm of strong biofilm forming MDR K. pneumoniae strains. Whole genome analysis revealed that SAKp11, with a genome size of 59,338bp, belonged to the Casjensviridae family, one of the less explored bacteriophage families. Comprehensive characterization of SAKp11 indicated its suitability for therapeutic use. Our study highlights the severity of drug-resistant K. pneumoniae in Indian healthcare and the inadequacy of current antibiotics, underscoring the potential of phages as an alternative therapeutic option.