Bacterial and Viral Coinfection in Idiopathic Pulmonary Fibrosis Patients: the Prevalence and Possible Role in Disease Progression

Abstract BackgroundIdiopathic pulmonary fibrosis (IPF) is a progressive interstitial pneumonia of unknown etiology with a mean survival rate of less than 3 years. Gap StatementNo previous studies have been performed on the role of co-infection (viral and bacterial infection) in the pathogensis and progression of IPF.AimIn this study, we investigated the role of viral/bacterial infection and coinfection and their possible association with pathogensis and progression of IPF.MethodsWe investigated the prevalence and impact of bacterial and viral coinfection in IPF patients (n = 67) in the context of pulmonary function (FVC, FEV1 and DLCO), disease status and mortality risk. Using principal component analysis (PCA), we also investigated the relationship between and distribution of bacterial and viral co-infection in the IPF cohort.ResultsOf the 67 samples, 17.9% samples were positive for viral infection, 10.4% samples were positive for bacterial infection and 59.7% samples were positive coinfection. We demonstrated that IPF patients who were co-infected had a significantly increased risk of mortality compared (p = 0.031) with IPF patients who were non-infected [Hazard ratio: 8.12; 95% C.I.: 1.3–26.9]. Furthermore, coinfection has also been implicated in disease progression during acute exacerbations in IPF (AE-IPF).ConclusionIn this study, we report for the first time that IPF patients who were coinfected with bacteria and viral infection have significantly decreased FVC and DLCO (% predicted), increased incidence of AE-IPF, increased incidence of death and risk of mortality compared with non-infected IPF patients.