HIV-1 genetic diversity and high prevalence of pretreatment drug resistance in Tianjin, China.

Background: Diversity of genotypes and prevalence of pretreatment drug resistance (PDR) challenge the epidemic control and vaccine development of HIV-1. However, little is known about the situation in Tianjin. Methods: Blood samples were collected from newly diagnosed antiretroviral treatment (ART)-naive HIV/AIDS patients from January 2016 to November 2019. Target fragment in the pol gene was sequenced after RNA extraction and gene amplification. HIV-1 genotype was identified by phylogenetic analysis. Drug resistance was carried out using the Stanford University HIVdb algorithm. Results: A total of 305 pol sequences from 279 non-PDR individuals and 35 PDR individuals were successfully amplified. The most prevalent genotype was CRF01_AE (65.6%, 200/305), followed by CRF07_BC (22.0%, 67/305) and B (3.0%, 9/305). A variety of circulating recombinant forms (CRFs) and unique recombinant forms (URFs) were found. The overall incidence of PDR was 11.5% (35/305) with 9.8% (30/305) to non-nucleoside reverse transcriptase inhibitors (NNRTIs). The most frequent mutation pattern against NNRTIs was V179D/E/T (6.9%, 21/305), with M184V (1.0%, 3/305) and K65R (1.0%, 3/305) against nucleoside reverse transcriptase inhibitors (NRTIs). M64L (0.1%, 1/305) was the sole mutation found against protease inhibitors (PIs). Eight variants generated at least low-level resistance to NNRTIs (2.6%, 8/305), which was much higher than that to NRTIs (1.6%, 5/305) and PIs (0/305) (P<0.05). Conclusions: Genotypic drug resistance testing before initiating ART in newly diagnosed HIV/AIDS patients may be necessary in Tianjin, China. Non-NNRTI-based regimen may be preferred as initial therapy in Tianjin.