Influenza-associated bacterial pneumonia; managing and controlling infection on two fronts

Abstract

Bacterial pneumonia complicating influenza is well-recognized as a severe manifestation of influenza, accounting for a substantial number of deaths from the 1918 influenza pandemic. Influenza-associated bacterial pneumonia remains a major contributor to the burden of influenza, and poses new challenges as antibiotic-resistant organisms such as methicillin-resistant Staphylococcus aureus spread. We provide an overview of the current state of knowledge of the epidemiology and co-pathogenesis of influenza-associated bacterial pneumonia, and outline management approaches and their limitations. We review preventative measures and discuss implications for pandemic planning. Knowledge gaps are underscored and future research directions are proposed.

The Influence of Influenza and Pneumococcal Vaccines on Community-Acquired Pneumonia (CAP) Outcomes Among Elderly Patients

“…Community-acquired pneumonia (CAP) is the most common type of pneumonia, and the incidence of CAP requiring hospitalization is highest among the elderly [4]. Influenza-associated bacterial pneumonia (i.e., combined bacterial-viral, or secondary bacterial) is more prevalent during seasonal outbreaks and pandemics than primary viral pneumonia [6,7]. The elderly are vulnerable to influenzaassociated pneumonias and it is recognized that CAP may result from viral coinfections like influenza [5,[7][8][9].…”

“…Pneumococcal pneumonias including CAP begin with asymptomatic nasopharynx colonization [6,8,9]. Recently, an eloquent series of studies in a murine model of coinfection demonstrated how influenza promotes pneumococcal proliferation during colonization [9].…”

“…The primary bacterial causes of influenzaa s s o c i a t e d p n e u m o n i a s a r e S . p n e u m o n i a e a n d Staphylococcus aureus [6,7]. The 30-day mortality among elderly with CAP has substantially declined in the past several decades, but estimates still suggest it is approximately 18 % [11].…”

“…The 30-day mortality among elderly with CAP has substantially declined in the past several decades, but estimates still suggest it is approximately 18 % [11]. Influenza-associated bacterial pneumonia morbidity and mortality are higher compared to influenza virus infection alone [6].…”

“…The elderly are highly vulnerable to influenza and CAP and may experience them either as coinfections or sequentially [5,6]. In the elderly, until recently, evidence of a direct effect of pneumococcal vaccines to prevent non-invasive CAP due to any cause including S. pneumonia was uncertain for PPV23 and limited for PCV13.…”