The pathogenesis of acute infection in COPD

Abstract

 To give an overview of the types of infectious agents involved in causing acute exacerbations of chronic obstructive pulmonary disease (COPD).  To outline the mechanisms through which infectious agents drive exacerbations.  To introduce the concept that mixed infections may increase the severity of exacerbations. Summary Infectious agents are implicated in a large majority of acute COPD exacerbations. The compro-mised defences of the patient's tracheobronchial system make it vulnerable to infection, with the consequent inflammatory and immune responses. A number of virulence factors have been associated with bacterial pathogens' propensity to cause exacerbations, and the genetic basis for these has begun to be examined. In addition, the acquisition of new strains of some bacteria has been associated with exacerbations. Viral nucleic acids are detected in about half of exacerbations, and several viruses are implicated, in particular rhinovirus. The manner in which these and other pathogens, individually and col-lectively, interact with the host merits further scrutiny if the prevention and treatment of acute COPD exacerbations are to be improved.