Pretreatment HIV-1 drug resistance and molecular subtype characteristics among newly diagnosed individuals in Guangxi, China.

BACKGROUND

The scale-up of antiretroviral therapy (ART) in China has increased concern regarding HIV-1 pretreatment drug resistance (PDR), particularly in Guangxi due to high subtype diversity and population mobility. However, the epidemiology and transmission dynamics of PDR in the region remain insufficiently characterized.

METHODS

We assessed PDR prevalence, subtype distribution, and transmission dynamics among ART-naïve individuals in central Guangxi. Between 2018 and 2023, 1,226 newly diagnosed individuals were screened, of whom 1,214 were included after quality control. Drug resistance mutations and subtypes were determined using the Stanford HIV Drug Resistance Database. Molecular transmission networks were constructed using the TN93 model with a genetic distance threshold of < 1.5%.

RESULTS

The study population was predominantly male (68.8%) and older (57.6% aged > 45 years). Overall, PDR prevalence was 6.0% (73/1,214; 95% CI 4.8-7.4%), ranging annually from 4.3 to 8.3%. CRF01_AE was the dominant subtype (74.3%), followed by CRF07_BC (11.1%) and CRF08_BC (10.3%). Higher PDR prevalence was observed in CRF08_BC (11.1%; 95% CI 6.6-17.9%) and CRF07_BC (8.8%; 95% CI 5.1-15.0%). Network analysis identified 102 transmission clusters comprising 612 sequences (50.4%), including two clusters containing ≥ 2 individuals sharing identical NNRTI resistance mutations, all linked through heterosexual transmission.

CONCLUSIONS

In central Guangxi, HIV-1 PDR remains moderate, primarily driven by NNRTI-associated mutations, with limited evidence of clustering within transmission networks. These findings highlight the need for continued resistance surveillance and optimization of first-line ART regimens. Trial registration Not applicable. This retrospective cohort study was not registered as a clinical trial.