Pandemic and seasonal influenza: therapeutic challenges

Abstract

Influenza A viruses cause significant morbidity and mortality annually, and the threat of a pandemic underscores the need for new therapeutic strategies. Here, we briefly discuss novel antiviral agents under investigation, the limitations of current antiviral therapy and stress the importance of secondary bacterial infections in seasonal and pandemic influenza. Additionally, the lack of new antibiotics available to treat increasingly drug resistant organisms such as methicillin-resistant Staphylococcus aureus, pneumococci, Acinetobacter, extended spectrum beta-lactamase producing gram negative bacteria and Clostridium difficile is highlighted as an important component of influenza treatment and pandemic preparedness. Addressing these problems will require a multidisciplinary approach, which includes the development of novel antivirals and new antibiotics, as well as a better understanding of the role secondary infections play on the morbidity and mortality of influenza infection.

Figure 1. Hematoxylin and Eosin-stained section of lung from a 1918 ‘Spanish’ influenza victim

Slide shows massive infiltrate of neutrophils that fills the alveolar air spaces in early bacterial bronchopneumonia. Alveolar capillary congestion is also prominent (original magnification 200×).

Figure 2. Antimicrobial resistance rates of select pathogens associated with nosocomial infections in intensive care unit patients in the United States 1999–2003

Data collected from hospitals around the United States by the CDC National Nosocomial Infections Surveillance System (NNIS) [46] over a four year period showed increases in antimicrobial resistance amongst common nosocomial pathogens: A. rates of methicillin resistance of Staphylococcus aureus isolates, B. resistance rates of pseudomonas species to multiple drugs commonly used to treat pulmonary and nosocomial infections, C. vancomycin resistance rates in enterococcal isolates, D. rates of resistance to 3^rd generation cephlosporins amongst Klebsiella pneumoniae isolates.