The goal of this observational study is to improve how hospital-acquired lung infections (called ventilator-associated pneumonia, or VAP) are diagnosed, treated and prevented in very low birth weight (VLBW) infants, babies born very early (preterm) or very small who often require respiratory support in hospital's neonatal intensive care units (NICUs). The main questions it aims to answer are: * How often do very-low-birth-weight (VLBW) infants get ventilator-associated pneumonia (VAP) in hospitals across Canada? * How often are these VAP infections caused by germs that are resistant to antimicrobials (also known as antimicrobial-resistant organisms or AROs)? * What types of antimicrobial-resistant germs (AROs) are causing them? * How are these infections being treated with antibiotics, and can we reduce unnecessary antibiotic use? * Which diagnostic definition is the best and most accurate for diagnosing VAP in newborns, based on real patient data and expert agreement? * Can we use this information to create clear, evidence-based guidelines that help hospitals prevent and treat VAP in the same, effective way? Researchers will compare how different hospitals define, report, and manage VAP to devise a shared, evidence-based approach that will lead to more accurate diagnoses and better treatment and outcomes for neonatal VAP. Researchers will: * Use data already collected in hospital records (per existing standard of clinical care). * Analyse how often VAP occurs, how it is diagnosed, and how it is treated * Work with experts and hospitals to develop and implement a standard, evidence-based plan for diagnosing, managing and preventing VAP in newborns The overarching goal is to create a clear, nationwide approach to ensure hospitals across Canada care for preterm babies in a standardized manner, reduce infection rates, avoid unnecessary antibiotic use, and improve outcomes for these vulnerable infants.