Detection of human influenza A (H1N1) and B strains with reduced sensitivity to neuraminidase inhibitors

详细信息    查看全文

• 作者：Vanessa Escuret ; Emilie Frobert ; Maude Bouscambert-Duchamp ; Murielle Sabatier ; Isidore Grog ; Martine Valette ; Bruno Lina ; Florence Morfin ; Olivier Ferraris
• 关键词：Influenza ; Neuraminidase inhibitors ; Resistance ; Systematic monitoring
• 刊名：Journal of Clinical Virology
• 出版年：2008
• 出版时间：January 2008
• 年：2008
• 卷：41
• 期：1
• 页码：25-28
• 全文大小：116 K

文摘

Neuraminidase inhibitors (NAIs) have been used since 2005 in France.

Objective

Influenza viruses isolated in hospital and community cases in winter 2005–2006 were evaluated for their sensitivity to NAIs.

Study design

Isolates were tested in duplicate with a fluorescence-based neuraminidase assay. The IC₅₀ for oseltamivir or zanamivir was calculated for each strain. Mean IC₅₀ (±S.D.) are expressed in nM. Viruses with IC₅₀ superior or very superior to the upper limit (mean IC₅₀ + 2.5 S.D.) were considered as outliers or resistant viruses, respectively. HA and NA genes for outliers, resistant strains and for a few sensitive strains were sequenced.

Results

Out of 225 B isolates, one was found resistant to both oseltamivir and zanamivir with a D197Y mutation in NA and eight isolates were outliers for oseltamivir and/or zanamivir. Out of 151 A (H1N1) isolates, one was found resistant to oseltamivir but sensitive to zanamivir with a H275Y mutation in NA, two isolates were resistant to zanamivir and three isolates were outliers for oseltamivir and/or zanamivir. New mutations were detected in outliers compared to sensitive viruses.

Conclusion

Resistant influenza strains to NAIs are circulating at a stable and low level of 1 % since the introduction of NAIs in clinical practice.