Altunok, Elif SargınSayan, MuratAkhan, SılaAygen, BilgehanYıldız, OrhanKoruk, Suda TekinMistik, Reşit2020-03-262020-03-2620161201-97121878-3511https://dx.doi.org/10.1016/j.ijid.2016.07.003https://hdl.handle.net/20.500.12395/33912Background: Drug resistance development is an expected problem during treatment with protease inhibitors (PIs), this is largely due to the fact that Pls are low-genetic barrier drugs. Resistance-associated variants (RAVs) however may also occur naturally, and prior to treatment with Pls, the clinical impact of this basal resistance remains unknown. In Turkey, there is yet to be an investigation into the hepatitis C (HCV) drug associated resistance to oral antivirals. Materials and methods: 178 antiviral-naive patients infected with HCV genotype 1 were selected from 27 clinical centers of various geographical regions in Turkey and included in the current study. The basal NS3 Pls resistance mutations of these patients were analyzed. Results: In 33 (18.5%) of the patients included in the study, at least one mutation pattern that can cause drug resistance was identified. The most frequently detected mutation pattern was T54S while R109K was the second most frequently detected. Following a more general examination of the patients studied, telaprevir (TVR) resistance in 27 patients (15.2%), boceprevir (BOC) resistance in 26 (14.6%) patients, simeprevir (SMV) resistance in 11 (6.2%) patients and faldaprevir resistance in 13 (7.3%) patients were detected. Our investigation also revealed that rebound developed in the presence of a Q80K mutation and amongst two V55A mutations following treatment with TVR, while no response to treatment was detected in a patient with a R55K mutation. Conclusion: We are of the opinion that drug resistance analyses can be beneficial and necessary in revealing which variants are responsible for pre-treatment natural resistance and which mutations are responsible for the viral breakthrough that may develop during the treatment. (C) 2016 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.en10.1016/j.ijid.2016.07.003info:eu-repo/semantics/openAccessBaseline resistancehepatitis C virusmutationprotease inhibitorsArticle501527401586Q1WOS:000388326300001Q2