Abstract
BACKGROUND: The increasing incidence of infections caused by extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) in Indonesia necessitates the exploration of phage therapy as a potential alternative treatment strategy. MATERIALS AND METHODS: A lytic phage capable of infecting ESBL-KP was isolated from the Cideng River in Jakarta and subsequently characterized morphologically and genomically. RESULTS: A novel lytic phage, designated JKT1, exhibited an icosahedral head (±52 nm diameter), a short tail, and formed large clear plaques with halos on bacterial lawns. JKT1 demonstrated rapid adsorption, a high burst size, and narrow host specificity. JKT1 remained stable at neutral pH and temperatures up to 37°C but lost activity at ≥50°C. Genome analysis revealed a 43,763 bp linear dsDNA genome encoding 57 open reading frames, including a putative depolymerase gene. Phylogenetic and genomic analyses classified JKT1 within the genus Drulisvirus. CONCLUSIONS: This study demonstrates JKT1's activity against specific capsular ESBL-KP strains, highlighting its targeted host range and potential for inclusion in phage cocktails for targeting bacterial infections.