Bactericidal Mechanism of Chlorous Acid Water in the Inactivation of Non-Tuberculous Mycobacteria

The global prevalence of pulmonary infections caused by non-tuberculous Mycobacteria (NTM), particularly the Mycobacterium avium complex (MAC), is increasing. Since NTM are ubiquitous in moist environments and resistant to standard disinfectants, this study evaluated the efficacy of chlorous acid water (CAW) against them. CAW demonstrated superior sanitizing effects compared to sodium hypochlorite (NaClO), efficiently inactivating NTM at 100 mg/L free available chlorine even in the presence of organic matter, where 1000 mg/L NaClO failed. Instead, subcellular fractionation and protein analysis revealed that CAW penetrates the cell to induce extensive aggregation of internal functional proteins, leading to the rapid collapse of membrane potential and ATP production. Furthermore, CAW exhibited significantly lower cytotoxicity toward human lung-derived A549 cells than NaClO. These results indicate that CAW inactivates NTM effectively by targeting internal protein stability and the respiratory chain, offering a potent and safer disinfection strategy for clinical and domestic environments.