OBJECTIVE: The objective of this study was to conduct a comprehensive analysis of the molecular transmission networks and transmitted drug resistance (TDR) patterns among individuals newly diagnosed with HIV-1 in Nanjing.
METHODS: Plasma samples were collected from newly diagnosed HIV patients in Nanjing between 2019 and 2021. The HIV pol gene was amplified, and the resulting sequences were utilized for determining TDR, identifying viral subtypes, and constructing molecular transmission network. Logistic regression analyses were employed to investigate the epidemiological characteristics associated with molecular transmission clusters.
RESULTS: A total of 1161 HIV pol sequences were successfully extracted from newly diagnosed individuals, each accompanied by reliable epidemiologic information. The analysis revealed the presence of multiple HIV-1 subtypes, with CRF 07_BC (40.57%) and CRF01_AE (38.42%) being the most prevalent. Additionally, six other subtypes and unique recombinant forms (URFs) were identified. The prevalence of TDR among the newly diagnosed cases was 7.84% during the study period. Employing a genetic distance threshold of 1.50%, the construction of the molecular transmission network resulted in the identification of 137 clusters, encompassing 613 nodes, which accounted for approximately 52.80% of the cases. Multivariate analysis indicated that individuals within these clusters were more likely to be aged ≥ 60, unemployed, baseline CD4 cell count ≥ 200 cells/mm3, and infected with the CRF119_0107 (P < 0.05). Furthermore, the analysis of larger clusters revealed that individuals aged ≥ 60, peasants, those without TDR, and individuals infected with the CRF119_0107 were more likely to be part of these clusters.
CONCLUSIONS: This study revealed the high risk of local HIV transmission and high TDR prevalence in Nanjing, especially the rapid spread of CRF119_0107. It is crucial to implement targeted interventions for the molecular transmission clusters identified in this study to effectively control the HIV epidemic.

OBJECTIVE: To elucidate the epidemiological features of HIV-2 in Hunan Province, China, utilizing sequence analysis.
METHODS: Thirteen individuals diagnosed with HIV-2 infection in Hunan Province, China, from 2017 to 2023 were included in this study. Amplification of HIV-2 env and pol regions was conducted, followed by Sanger sequencing. Phylogenetic and molecular transmission network analyses were performed to delineate molecular features and transmission dynamics.
RESULTS: All 14 individuals contracted HIV-2 through heterosexual intercourse, comprising 7 males and 7 females, with a median age of 58 years. Among them, three couples (HN001 and HN013, HN010 and HN011, HN008 and HN009) were identified, along with commercial sexual activity engagement reported for subject HN004. Notably, subjects HN001, HN003, HN008, and HN010 engaged in commercial sexual activities at the same location as subject HN004. Phylogenetic analysis of the pol gene revealed close proximity of sequences from all subjects to reference sequences from Gambia (Sub-type A). Employing a genetic distance threshold of 1.5 %, eight out of the 14 subjects formed a molecular transmission network, with HN002 and HN004 identified as central nodes.
CONCLUSIONS: From 2017 to 2023, all HIV-2-infected individuals in Hunan Province, China, acquired the virus through identifiable routes, indicating transmission of similar HIV-2 strains among them.

OBJECTIVE: To assess the profiles and determinants of drug resistance in HIV-1-infected individuals undergoing ART in Guangxi.
METHODS: Samples and data were collected from HIV-1-infected individuals experiencing virological failure post-ART from 14 cities in Guangxi. Sequencing of the HIV-1 pol gene was conducted, followed by analysis for drug resistance mutations using the Stanford University HIV Drug Resistance Database. Logistic regression was employed to identify potential risk factors associated with both HIV drug resistance and mortality.
RESULTS: A total of 8963 individuals with pol sequences were included in this study. The overall prevalence of HIV-1 drug resistance (HIVDR) was 42.43% (3808/8963), showing a decrease from 59.62% to 41.40% from 2016 to 2023. Factors such as being aged ≥50 years, male, Han nationality, lower education levels, occupations including workers, peasants and children, AIDS, pre-treatment CD4 T cell counts <200 cells/mm3, infection with CRF01_AE and CRF55_01B subtypes, and ART regimen lamivudine/zidovudine/nevirapine were associated with higher susceptibility to HIVDR. The common mutations were M184V (17.38%) and K103N (22.14%). Additionally, the prevalence of M184V, S68G, M41L and G190A were different between the Han and Zhuang populations. Factors including age, gender, ethnicity, education level, occupation, infectious route, clinical stage, viral load, subtype, ART regimen and HIVDR showed significant associations with mortality.
CONCLUSIONS: The factors contributing to drug resistance in the HIV-1 ART individuals in Guangxi appear to be notably intricate. Continuous reinforcement of drug resistance surveillance is imperative, accompanied by the optimization of ART regimens to mitigate virological failures effectively.

The distribution of human immunodeficiency virus-1 (HIV-1) subtypes indicates difference from region to region and in risk groups acquiring the disease worldwide. Although subtype C is more in terms of total cases, subtype B is dominant in certain regions, especially in western and central Europe. Molecular epidemiological studies are essential for the control, effective treatment, and understanding in transmission routes of HIV-1 infection. This study aims to determine the molecular epidemiology and antiretroviral drug resistance profiles of HIV-1 in northern Cyprus. The study involved 71 naive HIV-positive patients diagnosed in northern Cyprus between 2016 and 2022. HIV-1 subtypes and circulating recombinant forms (CRFs) were identified by phylogenetic analysis (neighbor-joining method) of pol gene sequences. Drug resistance mutations were analyzed using the World Health Organization (WHO) lists of mutations for surveillance. The Stanford University HIVdb program was used to interpret drug resistance mutations. In our study, 40 of 71 samples were successfully sequenced. Subtype B of HIV-1 was dominant with a rate of 52.5%, followed by CRF02_AG (20%) and G (7.5%) subtypes. The rate of subtype B (71.4%) in northern Cyprus was significantly higher than in the other country of origin (p = .028). Antiretroviral drug resistance was found in 15% of the sequenced serum samples. Nucleoside/nucleotide reverse transcriptase inhibitor (NRTI), non-nucleoside nucleotide reverse transcriptase inhibitor (NNRTI), and protease inhibitor (PI) resistance rates were 10% (4/40), 7.5% (3/40), and 2.5% (1/40), respectively. According to the results, it is noteworthy that the dominant subtype circulating in northern Cyprus is the B subtype, and CRFs were detected at a higher rate than expected.

To characterize the genetic diversity and drug resistance profiles of people with HIV-1 failing ART in Cape Verde (CV).
Cross-sectional study conducted between January 2019 and December 2021 in 24 health centres on the islands of Santiago and São Vicente.
The HIV-1 pol gene was sequenced in individuals with a detectable viral load. HIV-1 genetic diversity was determined by phylogenetic analysis. Drug resistance mutation patterns and resistance phenotypes were estimated using the Stanford algorithm.
Viral load was detected in 73 of 252 (29%) enrolled participants and sequencing data were produced for 58 (79%) participants. CRF02 AG strains predominated (46.5%), followed by subtype G (22.4%). Most patients (80%) had mutations conferring resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs) (67%), nucleoside reverse transcriptase inhibitors (55%), integrase inhibitors (10%) and/or protease inhibitors (7%) used in Cape Verde, a significant increase compared with a study conducted in 2010-2011. The most common mutations were M184V/I (43%), K103N/S (36%) and G190A/S (19%). NNRTI resistance was associated with younger age and exposure to two or more drug regimens.
The HIV-1 epidemic in Cape Verde is mainly driven by CRF02_AG and subtype G. Resistance to NNRTIs and/or NRTIs is highly prevalent and resistance to LPV/r and DTG is emerging. Our results support the use of DTG-based first-line ART and protease inhibitor-based regimens for patients with virological failure, but emerging resistance to LPV/r and DTG is a concern. Continued monitoring of drug resistance is essential to ensure adequate healthcare for PWH in Cape Verde.

Acquired immunodeficiency syndrome (AIDS) is caused by human immunodeficiency virus (HIV). HIV protease, reverse transcriptase, and integrase are targets of current drugs to treat the disease. However, anti-viral drug-resistant strains have emerged quickly due to the high mutation rate of the virus, leading to the demand for the development of new drugs. One attractive target is Gag-Pol polyprotein, which plays a key role in the life cycle of HIV. Recently, we found that a combination of M50I and V151I mutations in HIV-1 integrase can suppress virus release and inhibit the initiation of Gag-Pol autoprocessing and maturation without interfering with the dimerization of Gag-Pol. Additional mutations in integrase or RNase H domain in reverse transcriptase can compensate for the defect. However, the molecular mechanism is unknown. There is no tertiary structure of the full-length HIV-1 Pol protein available for further study. Therefore, we developed a workflow to predict the tertiary structure of HIV-1 NL4.3 Pol polyprotein. The modeled structure has comparable quality compared with the recently published partial HIV-1 Pol structure (PDB ID: 7SJX). Our HIV-1 NL4.3 Pol dimer model is the first full-length Pol tertiary structure. It can provide a structural platform for studying the autoprocessing mechanism of HIV-1 Pol and for developing new potent drugs. Moreover, the workflow can be used to predict other large protein structures that cannot be resolved via conventional experimental methods.

Proteolytic processing of human immunodeficiency virus type 1 particles mediated by viral protease (PR) is essential for acquiring virus infectivity. Activation of PR embedded in Gag-Pol is triggered by Gag-Pol dimerization during virus assembly. We previously reported that amino acid substitutions at the RT tryptophan repeat motif destabilize virus-associated RT and attenuate the ability of efavirenz (EFV, an RT dimerization enhancer) to increase PR-mediated Gag cleavage efficiency. Furthermore, a single amino acid change at RT significantly reduces virus yields due to enhanced Gag cleavage. These data raise the possibility of the RT domain contributing to PR activation by promoting Gag-Pol dimerization. To test this hypothesis, we investigated the putative involvement of a hydrophobic leucine repeat motif (LRM) spanning RT L282 to L310 in RT/RT interactions. We found that LRM amino acid substitutions led to RT instability and that RT is consequently susceptible to degradation by PR. The LRM mutants exhibited reduced Gag cleavage efficiencies while attenuating the EFV enhancement of Gag cleavage. In addition, an RT dimerization-defective mutant, W401A, reduced enhanced Gag cleavage via a leucine zipper (LZ) motif inserted at the deleted Gag-Pol region. Importantly, the presence of RT and integrase domains failed to counteract the LZ enhancement of Gag cleavage. A combination of the Gag cleavage enhancement factors EFV and W402A markedly impaired Gag cleavage, indicating a disruption of W402A Gag-Pol dimerization following EFV binding to W402A Gag-Pol. Our results support the idea that RT modulates PR activation by affecting Gag-Pol/Gag-Pol interaction. IMPORTANCE A stable reverse transcriptase (RT) p66/51 heterodimer is required for HIV-1 genome replication in host cells following virus entry. The activation of viral protease (PR) to mediate virus particle processing helps viruses acquire infectivity following cell release. RT and PR both appear to be major targets for inhibiting HIV-1 replication. We found a strong correlation between impaired p66/51RT stability and deficient PR-mediated Gag cleavage, suggesting that RT/RT interaction is critical for triggering PR activation via the promotion of adequate Gag-Pol dimerization. Accordingly, RT/RT interaction is a potentially advantageous method for anti-HIV/AIDS therapy if it is found to simultaneously block PR and RT enzymatic activity.

HIV-1CRF08_BC is the most prevalent epidemic subtype among heterosexual (HET) and intravenous drug users (IDUs) in Kunming, Yunnan. Using the pol region of gene sequences derived from molecular epidemiological surveys, we developed a molecular transmission network for the purpose of analyzing its epidemiological characteristics, assessing its epidemiological trends, identifying its potential transmission relationships, and developing targeted interventions. HyPhy 2.2.4 was used to calculate pairwise genetic distances between sequences; GraphPad-Prism 8.0 was employed to determine the standard genetic distance; and Cytoscope 3.7.2 was applied to visualize the network. We used the network analysis tools to investigate network characteristics and the Molecular Complex Detection (MCODE) tool to observe the growth of the network. We utilized a logistic regression model to examine the factors influencing clustering and a zero-inflated Poisson model to investigate the factors influencing potential transmission links. At the standard genetic distance threshold of 0.008, 406 out of 858 study participants were clustered in 132 dissemination networks with a total network linkage of 868, and the number of links per sequence ranged from 1 to 19. The MCODE analysis identified three significant modular clusters in the networks, with network scores ranging from 4.9 to 7. In models of logistic regression, HET, middle-aged and elderly individuals, and residents of northern and southeastern Kunming were more likely to enter the transmission network. According to the zero-inflated Poisson model, age, transmission category, sampling year, marital status, and CD4+ T level had a significant effect on the size of links. The molecular clusters in Kunming\'s molecular transmission network are specific and aggregate to a certain extent. HIV-1 molecular network analysis provided information on local transmission characteristics, and these findings helped to determine the priority of transmission-reduction interventions.

UNASSIGNED: An estimated 1.5 million Kenyans are HIV-seropositive, with 1.1 million on antiretroviral therapy (ART), with the majority of them unaware of their drug resistance status. In this study, we assessed the prevalence of drug resistance to nucleoside reverse transcriptase inhibitors (NRTIs), nucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors, and the variables associated with drug resistance in patients failing treatment in Nairobi, Kenya.This cross-sectional study utilized 128 HIV-positive plasma samples obtained from patients enrolled for routine viral monitoring in Nairobi clinics between 2015 and 2017. The primary outcome was human immunodeficiency virus type 1 (HIV-1) drug resistance mutation counts determined by Sanger sequencing of the polymerase (pol) gene followed by interpretation using Stanford\'s HIV Drug Resistance Database. Poisson regression was used to determine the effects of sex, viral load, age, HIV-subtype, treatment duration, and ART-regimen on the primary outcome.HIV-1 drug resistance mutations were found in 82.3% of the subjects, with 15.3% of subjects having triple-class ART resistance and 45.2% having dual-class resistance. NRTI primary mutations M184 V/I and K65R/E/N were found in 28.8% and 8.9% of subjects respectively, while NNRTI primary mutations K103N/S, G190A, and Y181C were found in 21.0%, 14.6%, and 10.9% of subjects. We found statistically significant evidence (P = .013) that the association between treatment duration and drug resistance mutations differed by sex. An increase of one natural-log transformed viral load unit was associated with 11% increase in drug resistance mutation counts (incidence rate ratio [IRR] 1.11; 95% CI 1.06-1.16; P < .001) after adjusting for age, HIV-1 subtype, and the sex-treatment duration interaction. Subjects who had been on treatment for 31 to 60 months had 63% higher resistance mutation counts (IRR 1.63; 95% CI 1.12-2.43; P = .013) compared to the reference group (<30 months). Similarly, patients on ART for 61 to 90 months were associated with 133% higher mutation counts than the reference group (IRR 2.33; 95% CI 1.59-3.49; P < .001). HIV-1 subtype, age, or ART-regimen were not associated with resistance mutation counts.Drug resistance mutations were found in alarmingly high numbers, and they were associated with viral load and treatment time. This finding emphasizes the importance of targeted resistance monitoring as a tool for addressing the problem.

Strains of the HIV-1 circulating recombinant forms (CRFs) 06_cpx and 56_cpx were identified for the first time in Guangzhou, China. The nearly full-length genome (NFLG) sequence was amplified, and the PCR products were sequenced by the Sanger method. The CRF06_cpx and CRF56_cpx strains were identified using the Basic Local Alignment Search Tool (BLAST) and confirmed by neighbour-joining (NJ) phylogenetic analysis. Additionally, these strains were found to contain transmitted drug resistance mutations that have little effect on first-line efavirenz (EFV)-based treatment. Genetic analysis of the detailed sequence data will provide more information on the HIV-1 epidemic in China.