Viral–bacterial co-infections in the respiratory tract

Highlights

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  Viruses predispose to secondary bacterial infection throughout the respiratory tract.

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  Viral damage to airway epithelium and aberrant inflammatory responses play key roles.

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  Dysregulation of both innate and acquired immune effectors contribute to co-infection.

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  Viral co-infection promotes bacterial invasion of sterile sites within the airway.

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  Optimal treatment likely requires control of both bacterial growth and host responses.

Abstract

Preceding or concurrent viral respiratory tract infection can predispose to secondary bacterial co-infection throughout the airway. The mechanisms by which viruses promote these superinfections are diverse and replete. Whereas we understand much as to how viruses damage the airway and dysregulate both innate and acquired immune responses which, in turn, supports bacterial growth, adherence and invasion into normally sterile sites within the respiratory tract, new information regarding these co-infections is being gained from recent advances in microbiome research and our enhanced appreciation of the contribution of bacterial biofilms, among others. The advanced understanding obtained by continued research efforts in all aspects of viral–bacterial co-infections of the respiratory tract will allow us to devise novel approaches for disease prevention as well as to develop more effective therapeutics.