Precision antibiotic treatment in intensive care unit-acquired lower respiratory tract infections (ICU-LRTIs): contemporary concepts and future directions

INTRODUCTION: Intensive care unit-acquired lower respiratory tract infections (ICU-LRTIs), including ventilator-associated pneumonia (VAP), ventilator-associated tracheobronchitis (VAT), and hospital-acquired pneumonia (vHAP) requiring invasive ventilation, remain among the most frequent and complex infections in critical care. Their management is challenged by diagnostic uncertainty, overlapping syndromes, and rising antimicrobial resistance. Despite advances in diagnostic and therapeutic tools, empirical broad-spectrum antibiotics remain the cornerstone of treatment, often started without microbiological confirmation. AREAS COVERED: This narrative review examines current approaches to ICU-LRTIs, with a focus on the growing role of bronchoscopy, molecular diagnostics, host biomarkers, and therapeutic drug monitoring (TDM). The need for harmonized definitions, such as ventilator-associated lower respiratory tract infection (VA-LRTI), is discussed to address diagnostic variability. The review also considers combined therapies, including nebulized antibiotics, novel antimicrobials targeting multidrug-resistant pathogens, and real-time TDM to optimize treatment in complex ICU cases. EXPERT OPINION: Management of VA-LRTIs is moving toward precision-guided care. Integrating bronchoscopy, molecular testing, and host-response profiling into routine practice can enable earlier, targeted therapy. Real-time TDM and local resistance surveillance should be standard to optimize antimicrobial use and prevent resistance. A shift from rigid syndromic classifications toward phenotype-driven management is needed to improve patient outcomes.