Role of trehalose polyphleates in the interactions between therapeutic phages and Mycobacterium abscessus

Cystic fibrosis patients are particularly susceptible to infections by the multidrug-resistant pathogen Mycobacterium abscessus (Mab), resulting in frequent therapeutic failures. Phage therapy, often in combination with antibiotics, has recently emerged as an alternative approach for the treatment of Mab pulmonary diseases. Despite its promise, the molecular mechanisms driving phage-host interactions and phage specificity in Mab remain poorly understood.

In this study, we investigated the role of mycobacterial surface components in the recognition and infection process of the therapeutic phage BPs targeting clinical Mab strains. Using a transposon mutant library, we identified phage-resistant Mab mutants, all carrying disruptions in genes involved in the biosynthesis of trehalose polyphleates (TPP), consisting of complex surface-associated lipids. In parallel, we also isolated spontaneous Mab mutants resistant to BPs with mutations in the TPP locus. Phage BPs failed to adsorb or infect TPP-deficient mutants, but these phenotypes were restored upon complementation of the disrupted genes.

To further elucidate this interaction, we employed fluorophages, enabling visualization and quantification of the infection process, to confirm the requirement of TPP in the adhesion process. Strikingly, we isolated BPs variants with mutations in the minor tail protein gp22, which conferred the ability to infect TPP-deficient Mab strains, illustrating a clear case of phage-bacteria co-evolution.

Our results uncover TPP as a novel receptor for mycobacteriophage adsorption and expand our understanding of early phage-host interaction mechanisms. Moreover, the identification of BPs variants with broader host range highlights their therapeutic potential against drug-resistant Mab, paving the way for the development of next-generation phage therapies against Mab diseases.