Surveillance of antiviral resistance markers in Argentina: detection of E119V neuraminidase mutation in a post-treatment immunocompromised patient

Abstract

Although vaccines are the best means of protection against influenza, neuraminidase inhibitors are currently the main antiviral treatment available to control severe influenza cases. One of the most frequent substitutions in the neuraminidase (NA) protein of influenza A(H3N2) viruses during or soon after oseltamivir administration is E119V mutation. We describe the emergence of a mixed viral population with the E119E/V mutation in the NA protein sequence in a post-treatment influenza sample collected from an immunocompromised patient in Argentina. This substitution was identified by a real-time reverse transcriptase polymerase chain reaction (RT-PCR) protocol and was confirmed by direct Sanger sequencing of the original sample. In 2014, out of 1140 influenza samples received at the National Influenza Centre, 888 samples (78%) were A(H3N2) strains, 244 (21.3%) were type B strains, and 8 (0.7%) were A(H1N1)pdm09 strains. Out of 888 A(H3N2) samples, 842 were tested for the E119V substitution by quantitative RT-PCR: 841 A(H3N2) samples had the wild-type E119 genotype and in one sample, a mixture of viral E119/ V119 subpopulations was detected. Influenza virus surveillance and antiviral resistance studies can lead to better decisions in health policies and help in medical treatment planning, especially for severe cases and immunocompromised patients.

Antiviral resistance markers in influenza virus sequences in Mexico, 2000–2017

“…The percentage of resistant strains may fluctuate depending on the country and geographical area: in USA, it has been reported at 1.2%, 16 in Brazil 1.4%, 17 in Argentina 0.1%, 18 and in Australia and Japan 18%. 19 , 20 In the sequences analyzed in this work, the predominant mutation was H275Y in both the H1N1 pdm09 and seasonal H1N1 subtypes, while the H3N2 subtype did not present this mutation (H274Y), and its overall resistance proportion was lower than that of the other two influenza A viruses.…”