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Lower Airway Bacteria in COPD: Differentiating True Colonization, Chronic Infection and Acute Infectious Exacerbations

Sethi S.

Respiratory Drug Delivery 2014. Volume 1, 2014: 15-24.

Abstract:

Differentiation between colonization and infection is determined by the impact of the presence of the pathogen on the host. There is growing evidence that the presence of bacteria in the lower airway in chronic obstructive pulmonary disease (COPD) induces damaging inflammation and specific host response, therefore meeting the criteria for infection. This infection can present in a subtle manner during the chronic stage of COPD, or be readily appreciated clinically as episodes of exacerbation and pneumonia. Compromised host innate lung defense due to tobacco or biomass smoke exposure are central for the susceptibility to infection seen in COPD. Several host lung defense defects are seen in COPD, of which dysfunctional macrophage response to bacterial pathogens prevalent in COPD could be the most significant. Pathogens prevalent in COPD have developed mechanisms to evade the host response such as biofilm formation and intracellular persistence. An entirely new therapeutic approach could develop in COPD with a focus on treating acute and chronic infections, and this is likely to include delivery of therapeutic agents directly to the lung.