Antiviral resistance in influenza viruses circulating in Central and South America based on the detection of established genetic markers

Abstract

Background Recent influenza antiviral resistance studies reveal an alarming increase in both adamantanes and neuraminidase inhibitors (NAIs) resistant viral strains worldwide, particularly in Asia, Europe and the United States. Objectives In this study, we have evaluated influenza virus resistance in Central and South America. Methods Influenza viruses, isolated from symptomatic patients throughout Central and South America in 2005–2008 were analyzed for inhibitor resistance. The M2 and NA genes of influenza viruses were sequenced and resistance was inferred by comparison with published sequences and known resistant mutations. Results Our results indicate that: (i) resistance to adamantanes was seen in the majority (95·5%) of the influenza A/H3N2 isolates but only in one isolate of the influenza A/H1N1 viruses; (ii) resistance to NAIs began to be detected in A/H1N1 isolates from Central America in 2008; and (iii) none of the influenza B viruses analyzed were resistant to NAIs. Conclusions These findings suggest a limited effectiveness of influenza inhibitors due to the detection of resistance among A/H1 and A/H3 viruses.

Genetic Analysis of Influenza A/H1N1 of Swine Origin Virus (SOIV) Circulating in Central and South America

“…12 Direct sequencing of RT-PCR products was carried out with the use of the Big Dye terminator cycle sequencing kit (version 3.1, Applied Biosystems ) on a Genetic Analyzer System (version 3130xL, Applied Biosystems).…”

Influenza in the tropics

“…The first data on resistance of influenza viruses circulating in some TSTCs were published recently. Amantadine-resistant and oseltamivir-resistant strains of influenza viruses (H3N2 and/or H1N1) have circulated in Asian and American TSTCs since 2005 [60,61]. Neuraminidase resistance was detected in influenza viruses that had circulated in Central America in 2008 [60].…”

Influenza a (H1n1) and the Resistance to Oseltamivir

“…The resistant cases found in greater numbers in Europe and the fact that the 7 resistant virus found in this study were collected in 2008 in Central and South Americas (Honduras, Nicaragua and Venezuela) suggest that the resistant virus is coming from the northern hemisphere to the south (Garcia et al, 2009).…”