Bacteriophage lysin P26ly combats multidrug-resistant Escherichia coli O157 and methicillin-resistant Staphylococcus aureus via cell wall degradation and membrane disruption

To address the growing challenge of antimicrobial resistance, we evaluated P26ly, a novel 17-kDa lysin derived from Shigella-infecting phage DS8 with a conserved lambda_lys-like domain. The antimicrobial effects of P26ly were assessed via turbidimetric, time-kill, and viability assays. Membrane disruption and Reactive Oxygen Species (ROS) accumulation were evaluated using fluorescence-based assays with multiple functional probes. Cellular damage was observed through scanning electron microscopy. P26ly was found to exhibit significant Antibacterial and antibiofilm activities against multidrug-resistant Escherichia coli O157 (Gram-negative) and methicillin-resistant Staphylococcus aureus (Gram-positive). Notably, P26ly effectively degraded Bacterial cell walls and disrupted cell membrane integrity, as evidenced by reduced membrane fluidity and proton motive force dissipation. These effects led to excessive ROS production and substantial ATP leakage, ultimately causing cell death. The dual mechanism of action of P26ly-cell wall degradation and membrane disruption-positions it as a promising candidate for bypassing conventional resistance mechanisms and effectively combating multidrug-resistant bacteria.

Antibacterial mechanism; Antibiotic resistance; Bacteriophage lysin; Biofilm; Protein expression.