Droplet digital PCR to investigate quasi-species at codons 119 and 275 of the A(H1N1)pdm09 neuraminidase during zanamivir and oseltamivir therapies.

The H275Y and E119D neuraminidase (NA) mutations constitute important molecular markers of resistance to NA inhibitors in A(H1N1) pdm09 viruses. We used reverse transcriptase-droplet digital PCR amplification (RT-ddPCR) to analyze quasi-species at codons 275 and 119 of the NA in A(H1N1) pdm09 viruses recovered from an immuncompromised patient who received oseltamivir and zanamivir therapies. RT-ddPCR assays detected and quantified H275Y and E119D mutations with an efficiency that was comparable to that of high throughput sequencing (HiSeq 2500 Illumina, San Diego, CA) technology. With its sensitivity and reproducibility, RT-ddPCR could be a reliable method for accurate detection and quantification of major NAI-resistance mutations in clinical settings. J. Med. Virol. 89:737-741, 2017.