Background Neuraminidase ( NA ) inhibitors ( NAI s) are currently the only antivirals effective against influenza infections due to widespread resistance to M 2 inhibitors. Methods Influenza A and B viruses ( n = 1079) collected worldwide between April 01, 2011, and September 30, 2011, were assessed for susceptibility to FDA ‐approved NAI s, oseltamivir and zanamivir, and investigational peramivir, using the fluorescent‐based NA ‐Fluor™ Influenza Neuraminidase Assay Kit. A subset of viruses ( n = 98) were tested for susceptibility to the investigational NAI , laninamivir. Results Influenza A(H1N1)pdm09 viruses ( n = 326) were sensitive to all NAI s, except for two (0·6%) with H275Y (N1 numbering; H274Y in N2 numbering) substitution, which exhibited elevated IC 50 s for oseltamivir and peramivir, and a third with previously unreported N325K substitution, exhibiting reduced susceptibility to oseltamivir. Influenza A(H3N2) viruses ( n = 407) were sensitive to all NAI s. Influenza B viruses ( n = 346) were sensitive to all NAI s, except two (0·6%) with H273Y (N1 numbering; H274Y in N2 numbering) substitution, exhibiting reduced susceptibility to oseltamivir and peramivir, and one with previously unreported G140R and N144K substitutions, exhibiting reduced susceptibility to oseltamivir, zanamivir, and peramivir. All influenza A and B viruses were sensitive to laninamivir. It is unknown whether substitutions N325K, G140R, and N144K were present in the virus prior to culturing because clinical specimens were unavailable for testing. Conclusions This study summarizes NAI susceptibility of influenza viruses circulating worldwide during the 2011 Southern Hemisphere ( SH ) season, assessed using the NA ‐Fluor™ Kit. Despite low resistance to NAI s among tested influenza viruses, constant surveillance of influenza virus susceptibility to NAI s should be emphasized.
【저자키워드】 oseltamivir, Influenza, southern hemisphere, zanamivir, neuraminidase inhibitor, Peramivir,