neuraminidaseresistant

Neuraminidase-resistant, or neuraminidase resistance, describes influenza viruses that have reduced susceptibility to neuraminidase inhibitors (NAIs), a class of antiviral drugs used to treat influenza. NAIs, including oseltamivir, zanamivir, peramivir, and laninamivir, target the viral neuraminidase enzyme, hindering release of new viral particles from infected cells.

Resistance arises mainly through mutations in the neuraminidase gene that diminish drug binding while preserving enzyme function. In some cases, compensatory changes elsewhere in the viral genome can help maintain fitness despite the mutation. Notable substitutions have been reported across different subtypes, and resistance patterns can vary by lineage and geography. Oseltamivir resistance is often linked to certain neuraminidase substitutions; zanamivir tends to retain activity against many oseltamivir-resistant strains, though cross-resistance is possible with some mutations. Peramivir and laninamivir resistance mirrors the shared mechanism but may differ in prevalence and clinical impact.

Diagnosis and surveillance rely on laboratory testing. Phenotypic neuraminidase inhibition assays measure the drug’s ability to inhibit neuraminidase activity, while genotypic assays detect known resistance mutations through sequencing. Ongoing surveillance by public health organizations tracks resistance trends and guides treatment recommendations.

Clinical implications include potential changes to therapy, especially for hospitalized or high-risk patients where resistance may affect outcomes. Alternatives may involve switching to a different NAI with retained activity or using non-NAI antivirals, depending on susceptibility data and patient factors. Research continues to monitor resistance development and to understand fitness costs and compensatory mechanisms associated with resistant variants.