Primers used for RT-PCR and nested PCR.

The high mutability of human immunodeficiency virus type 1 (HIV-1) and the widespread use of antiretroviral drugs have rendered genetic diversity and pre-treatment drug resistance (PDR) significant obstacles to the success of antiretroviral therapy (ART). However, the research on the epidemiological and spatial distribution characteristics of PDR in Ningxia is still insufficient. A cross-sectional study utilized pre-treatment blood samples collected between 2020 and 2021 from the biorepository in May 2024. Partial pol gene sequences were obtained through plasma collection and RNA extraction. Drug resistance analysis was performed using the Stanford University HIVdb algorithm. Molecular network were constructed using Cytoscape 3.10.0. Spatial analysis and visualization were further conducted using ArcGIS10.8.1. 95 sequences were obtained, among which 7 HIV-1 genotypes were detected and CRF07_BC (67.37%, 64/95) was the predominant one. Drug resistance mutations (DRMs) were detected in 13.68%(13/95) of the sequences. The risk of PDR occurrence was higher among individuals with CRF07_BC strain types. The 24 sequences of CRF07_BC, CRF01_AE, and URF subtypes grouped into nine transmission clusters in the molecular network, with CRF07_BC showing the highest integration and clustering rates. HIV-1 infections resistant to PDR were observed in all five cities in NHAR, accompanied by cross-city transmission. Additionally, seven imported sequences were detected, comprising CRF07_BC, CRF01_AE, and C subtypes, along with three sequences of CRF55_01B with high similarity to nonlocal sequences. From 2020 to 2021, the HIV-1 diversity increased significantly in NHAR, with the prevalence of PDR reaching moderate levels and evidence of resistance transmission. The districts and counties under the jurisdiction of Yinchuan City emerged as hotspots for both pre-treatment HIV/AIDS patients and the distribution of resistant strains. It is imperative to enhance PDR testing and implement targeted interventions in key areas to minimize the emergence and dissemination of resistant virus variants.