Characteristics of HIV-1 molecular transmission networks and drug resistance among men who have sex with men in Tianjin, China (2014-2018)

Abstract

Background: In Tianjin, China, there is a relatively high prevalence of HIV in men who have sex with men (MSM). The number of HIV cases in Tianjin is also increasing. We investigated the HIV molecular transmission network, genetic tropisms, and drug resistance mutations in Tianjin.

Methods: Blood samples were collected from 510 newly diagnosed antiretroviral therapy (ART)-naïve HIV-1-infected subjects among MSM in Tianjin. Partial pol and env genes were sequenced and used for phylogenetic, genetic tropism, and genotypic drug resistance analyses. Molecular clusters were identified with 1.5% genetic distance and 90% bootstrap support.

Results: Among the 436 HIV-1 pol sequences obtained from the study participants, various genotypes were identified, including CRF01_AE (56.9%), CRF07_BC (27.8%), B (7.3%), CRF55_01B (4.1%), unique recombinant forms (URFs) (3.7%), and CRF59_01B (0.2%). A higher prevalence of X4 viruses was observed in individuals infected with CRF55_01B (56.3%) and CRF01_AE (46.2%) than with other subtypes. Of all 110 sequences in the 36 clusters, 62 (56.4%) were observed in 23 CRF01_AE clusters and 18 (16.4%) in four CRF07_BC clusters. Eight sequences clustered with at least one other shared the same drug resistance mutation (DRM). In different cluster sizes, the distributions of individuals by age, presence of sexually transmitted disease, and presence of DRMs, were significantly different.

Conclusion: We revealed the characteristics of HIV molecular transmission, tropism, and DRMs of ART-naïve HIV-infected individuals among the MSM population in Tianjin. Identifying infected persons at risk of transmission is necessary for proposing counseling and treating these patients to reduce the risk of HIV transmission.

Keywords: Drug resistance; HIV-1; Men who have sex with men; Tianjin; Transmission network.

Fig. 1

HIV transmission clusters of pol identified from newly diagnosed ART-naïve HIV infections in the MSM population in Tianjin, China (2014–2018) by HIV genetic transmission network using HIV-TRACE by a ≤ 1.5% genetic distance. Black lines indicate the worst-based support (p) of the length between the two nodes < 0.05. Red lines indicate the worst-based support (p) of the length between the two nodes ≥ 0.05

Fig. 2

Phylogenetic tree analysis of partial pol (a) and env (b) region sequences from newly diagnosed ART-naïve HIV infections in the MSM population in Tianjin, China (2014–2018)

Fig. 3

X4 and R5 co-receptor tropism of HIV 384 env sequences were obtained for 436 subjects with pol sequences successfully amplified. a Co-receptor usage based on different subtypes; b co-receptor usage based on clustering. CRF circulating recombinant form, URFs unique recombinant forms