Role of neuraminidase in lethal synergism between influenza virus and Streptococcus pneumoniae.
A lethal synergism exists between influenza virus and Streptococcus pneumoniae, accounting for excess mortality during influenza epidemics. Using a model of viral-bacterial synergism, we assessed the role that the influenza virus neuraminidase (NA) has in priming mice for pneumococcal infection. Administration of the selective NA inhibitor oseltamivir improved survival, independent of viral replication and morbidity from influenza. Both pathologic examination of the lungs and live imaging of pneumonic lesions, using a bioluminescent pneumococcus, suggested that the effect of NA inhibition was to limit the extent of pneumococcal pneumonia during early infection. Adherence assays and immunohistochemical staining for sialic acids in lungs from infected mice demonstrated that the influenza virus NA potentiates development of pneumonia by stripping sialic acid from the lung, thus exposing receptors for pneumococcal adherence. Selective NA inhibitors may be useful clinically to interrupt this novel mechanism of synergism and to prevent excess mortality from secondary bacterial pneumonia.
McCullers
Jonathan A
JA
Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee 38105-2794, USA. jon.mccullers@stjude.org
Bartmess
Kimberly C
KC
D000081:Acetamides / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects; D002460:Cell Line; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D004847:Epithelial Cells / Q000382:microbiology; D005260:Female; D008168:Lung / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009439:Neuraminidase / Q000502:physiology*; D009975:Orthomyxoviridae / Q000201:enzymology; D009976:Orthomyxoviridae Infections / Q000150:complications* / Q000188:drug therapy / Q000473:pathology; D053139:Oseltamivir; D011018:Pneumonia, Pneumococcal / Q000188:drug therapy / Q000209:etiology* / Q000473:pathology; D013296:Streptococcus pneumoniae / Q000502:physiology
D000081:Acetamides; D004791:Enzyme Inhibitors; D053139:Oseltamivir; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid