Pseudomonas aeruginosa in Ventilator-Associated Pneumonia: A Comprehensive Review of Resistance and Clinical Outcomes

Ventilator-associated pneumonia (VAP) remains one of the most common and serious healthcare-associated infections in intensive care units (ICUs), contributing significantly to patient morbidity and mortality among patients on mechanical ventilation. Due to its virulence and increasing antimicrobial resistance, Pseudomonas aeruginosa poses a significant clinical challenge. This review provides a comprehensive analysis of the epidemiology, pathogenesis, resistance mechanisms, and clinical outcomes associated with P. aeruginosa-induced VAP. Among the most notable virulence mechanisms are quorum sensing, biofilm formation, type III secretion systems, and host immune defence resistance. Current therapeutic options, such as piperacillin-tazobactam, meropenem, and newer β-lactam/β-lactamase inhibitor combinations, are reviewed in the context of emerging resistance. Preventive strategies such as antimicrobial-coated endotracheal tubes, cuff pressure adjustment, and subglottic secretion drainage are also discussed. The rising incidence of multidrug-resistant P. aeruginosa indicates the critical requirement for enhanced antimicrobial stewardship and novel therapeutic approaches to lessen the impact of VAP in critically ill patients. Additionally, this review addresses intrinsic, acquired, and adaptive resistance mechanisms, the clinical burden associated with multidrug-resistant and extensively drug-resistant strains, including increased mortality and prolonged ICU stay, advancements in rapid diagnostic techniques such as molecular assays and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and emerging therapeutic strategies, including cefiderocol, bacteriophage therapy, and anti-biofilm approaches.