Phage-based decontamination has rarely been explored in real-world settings, particularly in the environments of patients undergoing extracorporeal membrane oxygenation (ECMO). This four-year prospective study aimed to evaluate the effectiveness of aerosolized phage cocktails tailored to combat target antibiotic-resistant species of Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The decontamination procedure with phage aerosols was proactively implemented before the admission of ECMO patients based on a thorough analysis of phage typing results from bacterial species isolated from prospective patient areas during the preceding two months. The phage cocktail formulation design also accounted for phage resistance development, phage families, and plaque characteristics. Throughout the study, 85 ECMO patients were monitored, with the environments of 22 patients undergoing phage decontamination. Fifty phage cocktails were prepared to target the identified species. Respiratory infections were most common among ECMO patients, accounting for 71.4 %. The ECMO duration for patients infected with the targeted species was significantly longer than that for noninfected patients (P = 0.019), with peak infection incidence occurring between 3 and 7 days of ECMO treatment (67.1 per 1000 ECMO days). Notably, none of the patients in phage-treated environments contracted infections from the targeted species. However, the overall incidence of bacterial infections did not significantly correlate with phage decontamination efforts, as phages are effective only against their specific hosts. This study demonstrates the potential of prophylactic phage decontamination to prevent specific infections, aligning with One Health principles by offering a sustainable alternative to antibiotics, potentially significantly reducing antibiotic use.