Therapeutically useful mycobacteriophages BPs and Muddy require trehalose polyphleates

Area of Science:

• Microbiology
• Virology
• Biochemistry

Background:

• Mycobacteriophages are promising therapeutics for non-tuberculous mycobacterial infections.
• Understanding phage-host interactions and resistance mechanisms is crucial for clinical application.

Purpose of the Study:

• To investigate the role of trehalose polyphleates (TPPs) in mycobacteriophage infection and resistance.
• To identify mechanisms of phage resistance in Mycobacterium abscessus and Mycobacterium smegmatis.
• To engineer TPP-independent phages for enhanced therapeutic efficacy.

Main Methods:

• Investigated phage adsorption and infection using TPP-deficient mycobacterial mutants.
• Employed transposon mutagenesis to identify genes involved in phage resistance.
• Characterized phage resistance mechanisms through genetic and protein analysis.
• Engineered clinically relevant phages (BPs and Muddy) for TPP independence.

Main Results:

• Trehalose polyphleates (TPPs) are essential for infection by phages BPs and Muddy.
• Loss of TPPs confers resistance to these phages by disrupting adsorption and infection.
• TPP synthesis gene mutations are a primary cause of phage resistance in clinical isolates.
• Single amino acid substitutions in phage tail spike proteins render BPs and Muddy TPP-independent.
• Additional resistance mechanisms exist in TPP-independent phage-resistant mutants.

Conclusions:

• TPPs are critical determinants of mycobacteriophage infectivity and host range.
• Phage resistance in mycobacteria frequently involves TPP loss.
• Engineered TPP-independent phages can overcome TPP-mediated resistance.
• Clinical deployment of TPP-independent phage mutants may prevent resistance development.