nfection and rejection are the two most common complications after lung transplantation (LTx) and are associated with increased morbidity and mortality. We aimed to examine the association between airway microbiota and infection and rejection in lung transplant recipients (LTRs).

Distinct airway microbiota was observed between clinical stable recipients (or event free), infection and rejection after LTx. Alpha and beta diversity were significantly different between event free and rejection, and between infection and rejection recipients. Ten differential genera were identified by LEfSe analyses, with Corynebacterium, unclassified Enterococcaceae and unclassified Lactobacillales enriched in infection recipients, while Rothia, Granulicatella, Neisseria, Actinomyces, Leptotrichia, Lactobacillus and unclassified Aerococcaceae more abundant in rejection LTRs. Random forest analyses indicated that the combination of the 10 microbiota and procalcitonin (PCT) and T lymphocyte showed an AUC of 0.894, 0.955 and 0.913 to differentiate between event free and infection, event free and rejection, and infection and rejection recipients, respectively.