Resistance Mutations in the reverse transcriptase of drug-naive and drug-treated individuals.

250 samples from 234 drug-naive patients and 115 samples from 78 treated A/AE patients were genotyped. 31 patients were sampled both prior to treatment and after treatment failure. RT mutations found in all A/AE naive patients were compared to those found in A/AE drug-treated ones and to samples from 254 drug naive and 60 drug treated B individuals diagnosed since 2001. The first available sample from each drug-naive individual was used for analysis. For mutation-frequency analysis of drug-treated patients each mutation was counted once. Only mutations showing statistically significant differences between drug-naive and drug-treated patients and/or between A/AE and B frequencies are included.Major NRTI related mutations included TAMs: M41L, D67N, K70R, L210W, T216Y/F and K219Q/E, as well as A62V, K65R, L74V/I, L77F, F116Y, Q151M and M184V/I. Major NNRTI mutations included A98G, L100I, K101E/P, K103N/S, V106A/M, V108I, Y181C, Y188C/H/I, G190A/S, P225H and K238T.NNRTIs – Non-nucleosides reverse transcriptase inhibitors; NS – Not significant; NRTIs – Nucleosides reverse transcriptase inhibitors;aSubtyping was performed using the Stanford Database Rapid Subtyping Tool [23]–[24]. According to that classification 192 patients had virus containing protease of subtype A and RT most similar to CRF01_AE; for 70 both the protease and the RT were CRF01_AE; 52 were of subtype A; and four had protease classified as CRF01_AE and RT classified as A. Other subtyping tools such as Geno2Pheno (http://www.geno2pheno.org/) or the Rega Subtyping Tool (http://jose.med.kuleuven.be/subtypetool/html/) [57] vary to some extent in the classification of variants.