Insights into the Interaction between Influenza Virus and Pneumococcus

Abstract

SUMMARY Bacterial infections following influenza are an important cause of morbidity and mortality worldwide. Based on the historical importance of pneumonia as a cause of death during pandemic influenza, the increasingly likely possibility that highly pathogenic avian influenza viruses will trigger the next worldwide pandemic underscores the need to understand the multiple mechanisms underlying the interaction between influenza virus and bacterial pathogens such as Streptococcus pneumoniae. There is ample evidence to support the historical view that influenza virus alters the lungs in a way that predisposes to adherence, invasion, and induction of disease by pneumococcus. Access to receptors is a key factor and may be facilitated by the virus through epithelial damage, by exposure or up-regulation of receptors, or by provoking the epithelial regeneration response to cytotoxic damage. More recent data indicate that alteration of the immune response by diminishing the ability of the host to clear pneumococcus or by amplification of the inflammatory cascade is another key factor. Identification and exploration of the underlying mechanisms responsible for this synergism will provide targets for prevention and treatment using drugs and vaccines.

Stimulation of Ebola virus production from persistent infection through activation of the Ras/MAPK pathway

“…Alternatively, phorbol esters or other naturally occurring homologues produced during restricted ecologic/climactic periods may account for this infrequency. The fact that LPS also was capable of enhancing EBOV productivity from mouse macrophages also belies the possibility of synergy between virus and bacteria as occurs for HIV and syphilis, influenza and Streptcoccus pneumoniae, and herpes and periodontal bacteria (53)(54)(55). Other factors also may contribute, including pregnancy, which has been suggested to play a role in the transmission of Hendra virus from bats to horses (56,57).…”

Pandemic H1N1 influenza A infection and (atypical) HUS—more than just another trigger?

“…Invasive infections due to Streptococcus pneumoniae, Staphylococcus aureus, group A Streptococcus and other bacterial pathogens may occur [15,16]. Notably, the relationship between influenza A and Streptococcus pneumoniae is well researched, with evidence of a bi-directional interaction between these two pathogens [17]. If co-infection is present, this makes it challenging in some patients to determine which of these pathogens is responsible for the severe pulmonary and/or septic-related complications in the setting of influenza illness.…”

Staphylococcus aureus colonization and non-influenza respiratory viruses: Interactions and synergism mechanisms

“…The role of interactions between viruses and bacteria in the pathogenesis of respiratory infections have been extensively studied in the literature and notably those between influenza viruses and S. aureus or S. pneumoniae [5–10]. However, interactions between S. aureus and non-influenza respiratory viruses were not reviewed recently.…”