N-acetylcysteine inhibits NETs, exhibits antibacterial and antibiofilm properties and enhances neutrophil function against Burkholderia pseudomallei

Burkholderia pseudomallei, the cause of melioidosis, forms biofilms that facilitate survival, alter antimicrobial susceptibility and promote disease recurrence. Neutrophils contribute to bacterial eradication through phagocytosis, degranulation and neutrophil extracellular traps (NETs). However, NETs are demonstrably insufficient to eradicate B. pseudomallei. This study has revealed the ability of NET fragments containing DNA to elevate B. pseudomallei biofilm formation, as evidenced by crystal-violet staining and confocal microscopy. Further investigation demonstrated that 15 mM N-acetylcysteine (NAC), efficiently suppressed NETs stimulated by B. pseudomallei and effectively prevented B. pseudomallei from forming NET-associated biofilm in the presence of polymorphonuclear leukocytes. Remarkably, we demonstrated that NAC has antibacterial properties against five clinical B. pseudomallei isolates through kinetic growth monitoring for 24 h. Interestingly, 15 mM NAC inhibits NET production and improves neutrophil-mediated killing through phagocytosis and degranulation, considerably diminishing survival of B. pseudomallei. Our findings suggest that NAC, a multifaceted therapeutic agent, holds significant potential as an adjunctive treatment against B. pseudomallei infection. NAC not only inhibits NETs but also enhances neutrophil functionality and exhibits remarkable antibacterial activity against B. pseudomallei. These properties may contribute to more effective eradication of B. pseudomallei by reducing biofilm formation associated with NETs and improving overall neutrophil-mediated immune responses.