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

Background: Idiopathic 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, FEV 1 and DL CO ), 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 DL CO (% predicted), increased incidence of AE-IPF, increased incidence of death and risk of mortality compared with non-infected IPF patients.