Surveillance for neuraminidase inhibitor resistance in human influenza viruses from Australia.
Two hundred and forty-five human influenza A and B viruses isolated in Australia between 1996 and 2003 were tested for their sensitivity to the NA inhibitor drugs, zanamivir and oseltamivir using a fluorescence-based neuraminidase inhibition assay. Based on mean IC50 values, influenza A viruses (with neuraminidase subtypes N1 and N2) were more sensitive to both the NA inhibitors than were influenza B strains. Influenza A viruses with a N1 subtype and influenza B strains both demonstrated a greater sensitivity to zanamivir than to oseltamivir carboxylate, whereas influenza A strains with a N2 subtype were more susceptible to oseltamivir carboxylate. A comparison of IC50 values for viruses isolated before and after the release of the NA inhibitors in Australia, found there was no significant difference in the sensitivity of strains to either neuraminidase inhibitor and none of the isolates tested showed clinically significant resistance.
Hurt
Aeron C
AC
WHO Collaborating Centre for Reference and Research on Influenza, Melbourne, Australia. Aeron_Hurt@csl.com.au
Barr
Ian G
IG
Durrant
Christopher J
CJ
Shaw
Robert P
RP
Sjogren
Helen M
HM
Hampson
Alan W
AW
D000081:Acetamides / Q000494:pharmacology / Q000627:therapeutic use; D000998:Antiviral Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001315:Australia / Q000453:epidemiology; D024882:Drug Resistance, Viral; D004791:Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D006146:Guanidines; D006801:Humans; D009980:Influenza A virus / Q000187:drug effects* / Q000302:isolation & purification; D009981:Influenza B virus / Q000187:drug effects* / Q000302:isolation & purification; D007251:Influenza, Human / Q000188:drug therapy / Q000453:epidemiology* / Q000209:etiology; D008826:Microbial Sensitivity Tests; D009439:Neuraminidase / Q000037:antagonists & inhibitors*; D053139:Oseltamivir; D011159:Population Surveillance / Q000379:methods; D011714:Pyrans; D012794:Sialic Acids / Q000494:pharmacology / Q000627:therapeutic use; D053243:Zanamivir
D000081:Acetamides; D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D006146:Guanidines; D011714:Pyrans; D012794:Sialic Acids; D053139:Oseltamivir; D009439:Neuraminidase; D053243:Zanamivir