Layered phage therapy exploits capsule-loss escape and altered antibiotic susceptibility in CG23 hypervirulent Klebsiella pneumoniae
Year: 2026
Type: preprint
Abstract: The rise of drug-resistant Klebsiella pneumoniae infections is prompting a re-evaluation of phage therapy as an alternative treatment. Phage therapy has achieved successful outcomes, yet important limitations persist, including the rapid emergence of phage resistance and the time required to source suitable phages. Combining multiple phages into a phage cocktail based on genetic diversity, morphology or distinct infection mechanisms is a common strategy to mitigate resistance. Phage pairing based on these criteria neither mitigates nor delays the emergence of resistance, using CG23 hypervirulent Klebsiella pneumoniae (hv Kp ) EC0675 as a model. In CG23 Kp strains, resistance arises through disruption of the capsular biosynthetic pathway, leading to capsule impairment and global cross-resistance to all capsule-active phages. Combining phages active against encapsulated wild-type bacteria with those active against capsule-deficient escape mutants can overcome this constraint, improving bacterial suppression in vitro and reducing bacterial burdens across multiple organs in a mouse systemic infection model. In parallel, phage-driven capsule loss increased susceptibility of hv Kp EC0675 to selected antibiotics targeting the bacterial envelope or cell wall in vitro . These findings highlight the contribution of capsule-associated resistance to phage cross-resistance in the CG23 Kp strains examined, and support further evaluation of phage combinations targeting both wild-type bacteria and resistant derivatives, including their use alongside selected antibiotics, informing future clinical translation.
Authors: Ayuni Norman, Jun Hao Liew, Lalit Mohan, Chanvutha Ron, Aryeh Chiam, Yan Sun, Indira Kartigayen, May Delos Santos, Yingying Li, Bernice Siu Yan Tan, Shu Xuan Tan, Raksha Anand, Evangeline, Kay En Low, Isabelle Bonne, Andrea Lay Hoon Kwa, Barry Kreiswirth, Yunn-Hwen Gan, Roland Huber, Pablo Bifani
Institutions: Agency for Science, Technology and Research, National University of Singapore, Infectious Diseases Labs, Bioinformatics Institute, Nanyang Technological University, Singapore-MIT Alliance for Research and Technology, Massachusetts Institute of Technology, Life Sciences Institute, Singapore General Hospital, Duke-NUS Medical School, Hackensack Meridian Health
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7223182068