Staphylococcus aureus and Influenza A Virus: Partners in Coinfection.

Michelle E Mulcahy,Rachel M Mcloughlin

doi:10.1128/mbio.02068-16

Abstract

ABSTRACTNasal carriage of Staphylococcus aureus is a significant risk factor for secondary staphylococcal pneumonia in influenza A virus (IAV)-infected hosts. However, little research has been undertaken to define the environmental and physiological changes that cause S. aureus to shift from commensal to pathogenic organism in this setting. The ability of virus-driven danger signals to cause S. aureus to transition from commensalism to pulmonary infection was explored in a recent study by Reddinger et al. R. M. Reddinger, N. R. Luke-Marshall, A. P. Hakansson, and A. A. Campagnari, mBio 7(6):e01235-16, 2016, http://dx.doi.org/10.1128/mBio.01235-16. The authors report that physiological host changes, including febrile temperature and a combination of host stress response signals, caused S. aureus biofilms to disperse from the nasal environment and cause active pulmonary infection. This commentary discusses the new finding in light of the current understanding of the mechanisms behind staphylococcal coinfection with IAV. In addition, it considers the mechanisms behind staphylococcal dispersal in this model. Overall, the study indicates that interkingdom signaling may occur following IAV infection and this likely contributes to sensitizing the IAV-infected host to secondary staphylococcal pneumonia.

Highlights

Staphylococcus aureus is a frequent perpetrator of secondary bacterial pneumonia following influenza A virus (IAV) infection
The majority of research on secondary staphylococcal respiratory infection has focused on IAV-elicited host immune factors that increase host susceptibility to secondary bacterial pneumonia due to an impaired or insufficient immune response to fight bacterial infection
IL-17 and IL-22 are both important determinants of S. aureus nasal carriage in vivo; IL-17 is important for neutrophilmediated clearance of S. aureus from the nose [11], while IL-22 controls local antimicrobial peptide production and staphylococcal ligand expression [12]

Summary

Introduction

Staphylococcus aureus is a frequent perpetrator of secondary bacterial pneumonia following influenza A virus (IAV) infection. The IAV-mediated host immune response may influence nasal carriage of S. aureus in an infected individual.

Results

Conclusion