LAUSR

BACKGROUND Transmitted drug resistances (TDRs) and HIV-1 diversity could affect treatment efficacy and clinical outcomes. Here we describe the circulating viral subtypes and estimate the prevalence of resistance among drug naïve patients attending Sapienza University Hospital in Rome from 2006-2017. METHODS Genotypic resistance test (GRT) was performed on 668 ART-naïve patients. GRT were conducted in integrase (n = 52), protease and reverse transcriptase (n = 668) sequences. RESULTS Twenty-one different subtypes and Circulating Recombinant Forms (CRFs) were identified. Subtype B was the most common (67%), followed by CRF02_AG (8.3%), subtypes C and F (6%). We found a significantly increased overtime in the proportion of non-B strains and in the rates of non-Italian patients (p < 0.001). The overall prevalence of TDR was 9.4% (NRTI: 4.2%, NNRTI: 5.8%, PI: 1%) and was higher in B strains. Transmitted INSTI mutations, Q148H and G140S, responsible for high-level of resistance to raltegravir and elvitegravir and intermediate resistance to dolutegravir and bictegravir were found, for the first time, in two individuals. Minor or accessory INSTI mutations were detected in 17.3% of patients. No significant decrease of TDR prevalence was documented overtime. CONCLUSION The significant increase of non-B subtypes suggests that the molecular epidemiology of HIV-1 is changing. The detection of a major INSTI mutation in two naïve patients highlights the importance of performing GRT before commencing treatment. This finding and the lack of a significant reduction of TDR underline the importance of a continuous surveillance of resistance mutations.