Endotracheal application of Ultraviolet A light in Pseudomonas aeruginosa ventilator-associated pneumonia: a sham-controlled large animal study

Ventilator-associated pneumonia (VAP) is a serious complication in mechanically ventilated patients, with high mortality and costs, so its prevention is a key issue. The narrow-band ultraviolet A (NB-UVA) catheter, emitting UVA light, demonstrated in vitro antimicrobial activity and could help decrease airway bacterial burden and prevent VAP. We aim to evaluate the efficacy and safety of an endotracheally inserted NB-UVA catheter in preventing VAP caused by extensively drug-resistant (XDR) Pseudomonas aeruginosa in a porcine model. Therefore, 10 intubated, mechanically ventilated pigs (41.0 [38.5–43.5] kg) were inoculated with XDR P. aeruginosa and randomized to receive UVA therapy (20 min, twice daily) or sham treatment. Tracheal aspirates and bronchoalveolar lavage (BAL) fluids were cultured, inflammatory markers measured, and catheter safety monitored. After 100 h, lung and trachea samples underwent microbiological and histological analysis. Nine animals completed the study. Lung tissue P. aeruginosa burden was similar between the NB-UVA and sham groups (1.48 [0–2.00] log CFU/g vs. 3.37 [2.23–4.32] log CFU/g, p = 0.26). However, microbiologically confirmed pneumonia occurred in fewer lobes (4/25 vs. 15/25, p = 0.003). UVA-treated animals had significantly lower tracheal P. aeruginosa concentrations at 12 h and less neutrophil-mediated interstitial infiltration at histopathological examination. Analysis of ELF cytokines revealed increased levels of IL-10 and reduced levels of IFN-γ. No histological abnormalities, changes in p53 expression, or major adverse events occurred. In conclusion, UVA therapy via the NB-UVA catheter may transiently delay airway the colonisation of the airways by XDR P. aeruginosa and influence the early progession of pneumonia, supporting further research of its potential as an adjunctive strategy for VAP prevention.