Invasive Bacterial Infections in Relation to Influenza Outbreaks, 2006-2010

Background. We aimed to define the excess morbidity associated with bloodstream infections (BSIs), imposed by pandemic H1N1 influenza during 2009–-2010 (pH1N1/2009–-2010) and seasonal influenza.

Methods. Eight hospitals, accounting for 33% of hospitalizations in Israel, provided data on BSI during 2006–2010. The age-specific incidence of BSI due to Streptococcus pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes was determined. BSI incidence rate ratios (IRRs) during seasonal and pH1N1 influenza seasons were assessed.

Conclusions. pH1N1 influenza seasons were characterized by marked increases in invasive S. aureus and S. pyogenes infections among children and adults, with the highest increase in S. pneumoniae BSI among children.