Circulating Recombinant Forms Research Articles

Analysis of the immunological response to antiviral therapy in patients with different subtypes of HIV/AIDS: a retrospective cohort study

ObjectiveTo evaluate the effectiveness of standardised antiretroviral therapy (ART) among different HIV subtypes in people living with HIV/AIDS (PLWHA), and to screen the best ART regimen for this patient population.DesignA...

Sequence Note: Characterization of Two HIV-1 Strains with Novel Unique Recombinant Genome in Hebei, China.

In China, the proportion of HIV-1 infections due to men who have sex with men (MSM) has increased rapidly. More and more new subtypes are found among the MSM population besides known CRF01_AE, CRF07_BC, and B. The co-circulation of several HIV subtypes in the same population provides the opportunity to develop a new circulating recombinant form (CRF) and unique recombinant form (URF). Here we reported two new URFs from two HIV-1 positive subjects infected through homosexual contact in Hebei, China. Phylogenetic and recombinant analyses based on the near full-length genome (NFLG) of the two URFs are the second-generation recombinant strains that originated from B, CRF01_AE, and CRF07_BC. The CRF01_AE segments in the genome of two URFs originated from cluster 4 of CRF01_AE strains, while the CRF07_BC segments were clustered with 07BC_N in the phylogenetic tree. The emergence of the novel CRF01_AE/CRF07_BC and CRF01_AE/B recombinant forms indicated the importance of the continuous monitoring of the HIV-1 epidemic and new URFs among the MSM population.

Molecular genetic characterization analysis of a novel HIV-1 circulating recombinant form (CRF156_0755) in Guangdong, China.

The characteristic of human immunodeficiency virus type 1 (HIV-1) is its susceptibility to erroneous replication and recombination, which plays a crucial role in the diverse and dynamic variation of HIV-1. The spread of different subtypes in the same population often leads to the emergence of circulating recombination forms (CRFs). At present, the main recombinant subtypes of HIV-1 in China are CRF07_BC, CRF01_AE, CRF08_BC and B' subtypes, while CRF55_01B has become the fifth major epidemic strain in China after rapid growth in recent years since it was first reported in 2013. In this study, we obtained five nearly full-length genomes (NFLGs) and one half-length genome from five different cities in Guangdong. Here, we focused on analyzing their characteristics, parental origin and drug resistance. Plasma samples were collected from six HIV-1 infected patients in Guangdong Province who had no epidemiological association with each other. The NFLGs of HIV-1 were amplified in two overlapping segments by the near-terminal dilution method. The positive products were sequenced directly to obtain genomic sequences. The recombinant patterns and breakpoints of the NFLGs were determined using the Simplot software and confirmed by the maximum likelihood trees for segments using the IQ-TREE and BEAST software. The genotypic resistance profiles of the protease reverse transcriptase and integrase were resolved by the Stanford HIV drug resistance database. The six genomes shared highly similar recombinant pattern, with the CRF55_01B backbone substituted by CRF07_BC segments, therefore assigned as CRF156_0755. The evolutionary analysis of the segments showed that CRF07_BC segments were not clustered with the Chinese MSM variants in the CRF07_BC lineage. All the five NFLGs were identified with the non-nucleoside reverse-transcription inhibitors (NNRTIs) resistance mutation V179E. With the accumulation and evolution of recombination between CRF55_01B and CRF 07_BC, the prevalence of more recombinant strains of CRF55_01B and CRF 07_BC may occur. Therefore, it is necessary to strengthen the identification and monitoring of the recombination of CRF55_01B and CRF 07_BC.

Identification of New Circulating Recombinant Form of HIV-1 CRF127_07109 in Northern Vietnam.

Some candidates of a new circulating recombinant form (CRF) of HIV-1 were found in northern Vietnam in our previous study. We succeeded in near full-length sequencing using MinION with plasma samples from 12 people living with HIV. Three of the samples were CRF109_0107, which was recently reported in China. Three others were the newly identified CRF127_07109, while six of them were considered to be CRF127_07109-related unique recombinant forms (URFs). The time to the most recent common ancestor of CRF127_07109 was estimated to be between 2015 and 2019. Our findings showed that CRF127_07109 and related URFs were generated recently in northern Vietnam, rather than migrated independently to northern Vietnam.

Identification of a novel HIV-1 third-generation circulating recombinant form (CRF126_0755) in Guangdong, China

The genetic recombination patterns and genetic distribution of HIV-1 are valuable for elucidating the epidemic and genetic diversity of HIV. Numerous HIV-1 circulating recombinant forms (CRFs) have recently emerged and disseminated rapidly. In China, at least 32 CRFs have been reported to account for more than 80% of all HIV infections. However, CRFs derived from the CRF07_BC and CRF55_01B lineages have never been recorded. Here, a novel third-generation CRF involving HIV-1 was identified in four HIV-1-infected patients in Guangdong, China, who had no epidemiological association with each other. Phylogenetic and recombinant analyses confirmed that these strains shared highly similar recombination patterns, with the CRF07_BC backbone substituted by a CRF55_01B segment; therefore, these strains were classified as CRF126_0755. This is the first study of a CRF derived from CRF07_BC and CRF55_01B. Bayesian phylogenetic inference suggested that CRF126_0755 originated in approximately 2005-2007. The present findings reveal that the genotype composition of HIV-1 has become more complex than that of other viruses and highlight the urgent need for continuous molecular screening and epidemic surveillance within HIV-1-infected populations to advance our understanding of viral transmission mechanisms.

Near-full-length genome analysis of two novel HIV second recombinant forms in Hebei, China.

The number of individuals infected with HIV-1 among men who have sex with men (MSM) has risen rapidly in recent years in China, and the subtypes CRF01_AE, CRF07_BC, and B, as well as many novel unique recombinant forms (URFs) are prevalent among them. Co-circulation of strains among MSM populations allows the generation of circulating recombinant forms (CRFs) and URFs. In this study, we identified two new URFs from two HIV-1-positive subjects who were infected through homosexual contact in Hebei, China. Analysis of near-full-length genome sequences, using phylogenetic and recombination analysis showed that the two URFs originated from CRF01_AE, CRF07_BC, and B, and CRF01_AE segments in the backbone of the URFs were derived from cluster 4 of CRF01_AE. The CRF07_BC segments of two URFs were clustered with 07BC_N in a phylogenetic tree. The identification of novel URFs with complex genomic structures shows that it is necessary to strengthen surveillance of HIV-1 variants in MSM populations in this region.

High HIV diversity, recombination, and superinfection revealed in a large outbreak among persons who inject drugs in Kentucky and Ohio, USA.

We investigated transmission dynamics of a large human immunodeficiency virus (HIV) outbreak among persons who inject drugs (PWID) in KY and OH during 2017-20 by using detailed phylogenetic, network, recombination, and cluster dating analyses. Using polymerase (pol) sequences from 193 people associated with the investigation, we document high HIV-1 diversity, including Subtype B (44.6 per cent); numerous circulating recombinant forms (CRFs) including CRF02_AG (2.5 per cent) and CRF02_AG-like (21.8 per cent); and many unique recombinant forms composed of CRFs with major subtypes and sub-subtypes [CRF02_AG/B (24.3 per cent), B/CRF02_AG/B (0.5 per cent), and A6/D/B (6.4 per cent)]. Cluster analysis of sequences using a 1.5 per cent genetic distance identified thirteen clusters, including a seventy-five-member cluster composed of CRF02_AG-like and CRF02_AG/B, an eighteen-member CRF02_AG/B cluster, Subtype B clusters of sizes ranging from two to twenty-three, and a nine-member A6/D and A6/D/B cluster. Recombination and phylogenetic analyses identified CRF02_AG/B variants with ten unique breakpoints likely originating from Subtype B and CRF02_AG-like viruses in the largest clusters. The addition of contact tracing results from OH to the genetic networks identified linkage between persons with Subtype B, CRF02_AG, and CRF02_AG/B sequences in the clusters supporting de novo recombinant generation. Superinfection prevalence was 13.3 per cent (8/60) in persons with multiple specimens and included infection with B and CRF02_AG; B and CRF02_AG/B; or B and A6/D/B. In addition to the presence of multiple, distinct molecular clusters associated with this outbreak, cluster dating inferred transmission associated with the largest molecular cluster occurred as early as 2006, with high transmission rates during 2017-8 in certain other molecular clusters. This outbreak among PWID in KY and OH was likely driven by rapid transmission of multiple HIV-1 variants including de novo viral recombinants from circulating viruses within the community. Our findings documenting the high HIV-1 transmission rate and clustering through partner services and molecular clusters emphasize the importance of leveraging multiple different data sources and analyses, including those from disease intervention specialist investigations, to better understand outbreak dynamics and interrupt HIV spread.

HIV-1 Gag, Pol, and Env diversified with limited adaptation since the 1980s.

Global surveillance of HIV-1 sequences is critical for designing relevant prophylactic and therapeutic interventions to infection. We designed an open-source platform, Hervé, for analyzing and visualizing the diversification dynamics of HIV-1 protein sequences. We characterized the evolution of over 12,000 HIV-1 Env, Gag, and Pol protein sequences from 1980-2020 and found that, despite a steady increase in intra-subtype and circulating recombinant form diversity, the most frequent residue at each site, i.e., the consensus, has varied only moderately.

Criteria for classification, nomenclature, and reference sequence selection for HIV sub-subtypes of CRF01_AE and CRF07_BC strains in China.

The available knowledge regarding classification, nomenclature, and reference sequence selection for the various sub-subtypes of circulating recombinant forms (CRFs) is inadequate to fulfill the growing demands of research focused on HIV prevention. We analyzed the spread of CRF01_AE and CRF07_BC strains, mainly in China, to complement and update the existing nomenclature and to propose a reference sequence selection criteria for sub-subtypes of CRFs.

Geno2pheno: recombination detection for HIV-1 and HEV subtypes

Abstract Even after three decades of antiretroviral therapy for HIV-1 (human immunodeficiency virus 1), therapy failure is a continual challenge. This is especially so if the viral variant is a recombinant of subtypes. Thus, improved diagnosis of recombined subtypes can help with the selection of therapy. We are using a new implementation of the previously published computational method recco to detect de novo recombination of known subtypes, independent of and in addition to known circulating recombinant forms (CRFs). We detect an optimal path in a multiple alignment of viral reference sequences based on mutation calls and probable breakpoints for recombination. A tuning parameter is used to favor either mutation calls or breakpoints. Besides novel recombinants, our tool g2p-recco integrated in the geno2pheno web service (https://geno2pheno.org) can successfully detect known recombinant events given only the full consensus references (without CRFs) of the involved subtypes with breakpoints. In addition, the tool can be applied to other viruses, i.e. hepatitis E virus (HEV). In this fashion, we could also detect several previously unknown recombinations in HEV.

Genetic characteristics of a novel HIV-1 circulating recombinant form (CRF128_07B) identified among MSM in Guangdong Province, China

ObjectiveTo obtain and investigate the genetic characteristics of four HIV-1 near full-length genome sequences (NFLGs), aiming at a description of a novel circulating recombinant form (CRF) in Guangdong China. MethodsPlasma samples were collected from HIV-1 infected MSM patients in Guangdong Province who had no epidemiological association with each other. The NFLGs were amplified with two overlapping halves and phylogenetic analyses were performed using Mega V11.0.1. Recombination analyses were comprehensively screened with the jpHMM, RIP, and BootScan analyses. Finally, the Bayesian phylogenetic analyses were performed using Beast V1.10.4 to estimate the origin time. ResultsPhylogenetic analyses revealed the four NFLGs formed a distinct monophyletic cluster distinguished from other known subtypes in the Neighbor-joining tree. Recombinant analyses revealed they shared a highly similar recombinant pattern, with the CRF07_BC backbone substituted by three subtype B segments. Subregion phylogenetic analyses confirmed them to be a novel CRF composed of CRF07_BC and subtype B, therefore, designed as CRF128_07B. According to the Bayesian phylogenetic analyses, CRF128_07B was inferred to approximately originated around 2005–2006. ConclusionsThese findings described a novel HIV-1 CRF identified from MSM in Guangdong Province. This is the first detection of a CRF comprising CRF07_BC and subtype B. The present finding highlights the urgent need for continuous molecular screening and the epidemic surveillance within the MSM populations.

Comprehensive Genetic Characterization of Four Novel HIV-1 Circulating Recombinant Forms (CRF129_56G, CRF130_A1B, CRF131_A1B, and CRF138_cpx): Insights from Molecular Epidemiology in Cyprus.

Molecular investigations of the HIV-1 pol region (2253-5250 in the HXB2 genome) were conducted on sequences obtained from 331 individuals infected with HIV-1 in Cyprus between 2017 and 2021. This study unveiled four distinct HIV-1 putative transmission clusters, encompassing 19 previously unidentified HIV-1 recombinants. These recombinants, each comprising eight, three, four, and four sequences, respectively, did not align with previously established Circulating Recombinant Forms (CRFs). To characterize these novel HIV-1 recombinants, near-full-length genome sequences were successfully obtained for 16 of the 19 recombinants (790-8795 in the HXB2 genome) using an in-house-developed RT-PCR assay. Phylogenetic analyses, employing MEGAX and Cluster-Picker, along with confirmatory neighbor-joining tree analyses of subregions, were conducted to identify distinct clusters and determine subtypes. The uniqueness of the HIV-1 recombinants was evident in their exclusive clustering within generated maximum likelihood trees. Recombination analyses highlighted the distinct chimeric nature of these recombinants, with consistent mosaic patterns observed across all sequences within each of the four putative transmission clusters. Conclusive genetic characterization identified four novel HIV-1 CRFs: CRF129_56G, CRF130_A1B, CRF131_A1B, and CRF138_cpx. CRF129_56G exhibited two recombination breakpoints and three fragments of subtypes CRF56_cpx and G. Both CRF130_A1B and CRF131_A1B featured seven recombination breakpoints and eight fragments of subtypes A1 and B. CRF138_cpx displayed five recombination breakpoints and six fragments of subtypes CRF22_01A1 and F2, along with an unclassified fragment. Additional BLAST analyses identified a Unique Recombinant Form (URF) of CRF138_cpx with three additional recombination sites, involving subtype F2, a fragment of unknown subtype origin, and CRF138_cpx. Post-identification, all putative transmission clusters remained active, with CRF130_A1B, CRF131_A1B, and CRF138_cpx clusters exhibiting further growth. Furthermore, international connections were identified through BLAST analyses, linking one sequence from the USA to the CRF130_A1B strain, and three sequences from Belgium and Cameroon to the CRF138_cpx strain. This study contributes valuable insights into the dynamic landscape of HIV-1 diversity and transmission patterns, emphasizing the need for ongoing molecular surveillance and global collaboration in tracking emerging viral variants.

Identification of a HIV-1 circulating BF1 recombinant form (CRF75_BF1) of Brazilian origin that also circulates in Southwestern Europe.

The high recombinogenic potential of HIV-1 has resulted in the generation of countless unique recombinant forms (URFs) and around 120 reported circulating recombinant forms (CRFs). Here we identify through analyses of near full-length genomes (NFLG) a new HIV-1 CRF derived from subtypes B and F1. HIV-1 protease-reverse transcriptase (Pr-RT) sequences were obtained by RT-PCR amplification from plasma RNA. Near full-length genome sequences were obtained after amplification by RT-PCR in 5 overlapping fragments. Phylogenetic sequence analyses were performed via maximum likelihood. Mosaic structures were analyzed by bootscanning and phylogenetic analyses of genome segments. Temporal and geographical estimations of clade emergence were performed with a Bayesian coalescent method. Through phylogenetic analyses of HIV-1 Pr-RT sequences obtained by us from samples collected in Spain and downloaded from databases, we identified a BF1 recombinant cluster segregating from previously reported CRFs comprising 52 viruses, most from Brazil (n = 26), Spain (n = 11), and Italy (n = 9). The analyses of NFLG genomes of 4 viruses of the cluster, 2 from Spain and 2 from Italy, allowed to identify a new CRF, designated CRF75_BF1, which exhibits a complex mosaic structure with 20 breakpoints. All 4 patients harboring CRF75_BF1 viruses studied by us had CD4+ T-cell lymphocyte counts below 220/mm3 less than one year after diagnosis, a proportion significantly higher (p = 0.0074) than the 29% found in other patients studied in Spain by us during the same period. The origin of the clade comprising CRF75_BF1 and related viruses was estimated around 1984 in Brazil, with subsequent introduction of CRF75_BF1 in Italy around 1992, and migration from Italy to Spain around 1999. A new HIV-1 CRF, designated CRF75_BF1, has been identified. CRF75_BF1 is the 6th CRF of South American origin initially identified in Western Europe, reflecting the increasing relationship of South American and European HIV-1 epidemics. The finding of low CD4+ T-cell lymphocyte counts early after diagnosis in patients harboring CRF75_BF1 viruses warrants further investigation on the virulence of this variant.

HIV-1 Resistance to Islatravir/Tenofovir Combination Therapy in Wild-Type or NRTI-Resistant Strains of Diverse HIV-1 Subtypes.

Tenofovir disoproxil fumarate (TDF) and islatravir (ISL, 4'-ethynyl-2-fluoro-2'-deoxyadensine, or MK-8591) are highly potent nucleoside reverse transcriptase inhibitors. Resistance to TDF and ISL is conferred by K65R and M184V, respectively. Furthermore, K65R and M184V increase sensitivity to ISL and TDF, respectively. Therefore, these two nucleoside analogs have opposing resistance profiles and could present a high genetic barrier to resistance. To explore resistance to TDF and ISL in combination, we performed passaging experiments with HIV-1 WT, K65R, or M184V in the presence of ISL and TDF. We identified K65R, M184V, and S68G/N mutations. The mutant most resistant to ISL was S68N/M184V, yet it remained susceptible to TDF. To further confirm our cellular findings, we implemented an endogenous reverse transcriptase assay to verify in vitro potency. To better understand the impact of these resistance mutations in the context of global infection, we determined potency of ISL and TDF against HIV subtypes A, B, C, D, and circulating recombinant forms (CRF) 01_AE and 02_AG with and without resistance mutations. In all isolates studied, we found K65R imparted hypersensitivity to ISL whereas M184V conferred resistance. We demonstrated that the S68G polymorphism can enhance fitness of drug-resistant mutants in some genetic backgrounds. Collectively, the data suggest that the opposing resistance profiles of ISL and TDF suggest that a combination of the two drugs could be a promising drug regimen for the treatment of patients infected with any HIV-1 subtype, including those who have failed 3TC/FTC-based therapies.

Near Full-Length Genomic Characterization of Two Novel HIV Type 1 Second-Generation Recombinant Forms (CRF01_AE/CRF07_BC) from Guangxi, China.

CRF01_AE and CRF07_BC are the two predominant HIV-1 subtypes currently circulating in China. We identified here a novel CCR5-tropic HIV-1 second-generation recombinant form virus found in two individuals, (GX19017 and GX19032), which were isolated from two HIV-1-positive people in Guangxi, southwest China. Phylogenic analyses indicated that these two sequences were all composed of two well-established circulating recombinant forms (CRFs) CRF07_BC and CRF01_AE, with four recombinant breakpoints observed in the pol, vpu/env, and env gene regions, respectively. The recombinant CRF01_AE region was clustered with the previously described CRF01_AE subcluster 2 lineage, which was characterized by the susceptibility to phenotypic transfer. The genome structure is significantly different from other previously reported CRFs and unique recombination forms. The emergence of a series of novel recombinant strains is indicative of the burgeoning complexity of the HIV-1 epidemic among the sexually transmitted population. Meanwhile, it may furnish significant insights into the dynamics and intricacy of the HIV-1 epidemic in China.

Structures and immune recognition of Env trimers from two Asia prevalent HIV-1 CRFs

Structure-guided immunofocusing HIV-1 vaccine design entails a comprehensive understanding of Envs from diverse HIV-1 subtypes, including circulating recombinant forms (CRFs). Here, we present the cryo-EM structures of Envs from two Asia prevalent CRFs (CRF01_AE and CRF07_BC) at 3.0 and 3.5 Å. We compare the structures and glycosylation patterns of Envs from different subtypes and perform cross-clade statistical analyses to reveal the unique features of CRF01_AE V1 region, which are associated with the resistance to certain bNAbs. We also solve a 4.1 Å cryo-EM structure of CRF01_AE Env in complex with F6, the first bNAb from CRF01_AE-infected individuals. F6 recognizes a gp120-gp41 spanning epitope to allosterically destabilize the Env trimer apex and weaken inter-protomer packing, which in turn hinders the receptor binding and induces Env trimer disassembly, demonstrating a dual mechanism of neutralization. These findings broaden our understanding of CRF Envs and shed lights on immunofocusing HIV-1 vaccine design.

Global associations of key populations with HIV-1 recombinants: a systematic review, global survey, and individual participant data meta-analysis.

Global HIV infections due to HIV-1 recombinants are increasing and impede prevention and treatment efforts. Key populations suffer most new HIV infections, but their role in the spread of HIV-1 recombinants is unknown. We conducted a global analysis of the associations between key populations and HIV-1 recombinants. We searched PubMed, EMBASE, CINAHL, and Global Health for HIV-1 subtyping studies published from 1/1/1990 to 31/12/2015. Unpublished data was collected through a global survey. We included studies with HIV-1 subtyping data of key populations collected during 1990-2015. Key populations assessed were heterosexual people (HET), men who have sex with men (MSM), people who inject drugs (PWID), vertical transmissions (VERT), commercial sex workers (CSW), and transfusion-associated infections (BLOOD). Logistic regression was used to determine associations of key populations with HIV-1 recombinants. Subgroup analyses were performed for circulating recombinant forms (CRFs), unique recombinant forms (URFs), regions, and time periods. Eight hundred and eighty five datasets including 77,284 participants from 83 countries were included. Globally, PWID were associated with the greatest odds of recombinants and CRFs (OR 2.6 [95% CI 2.46-2.74] and 2.99 [2.83-3.16]), compared to HET. CSW were associated with increased odds of recombinants and URFs (1.59 [1.44-1.75] and 3.61 [3.15-4.13]). VERT and BLOOD were associated with decreased odds of recombinants (0.58 [0.54-0.63] and 0.43 [0.33-0.56]). MSM were associated with increased odds of recombinants in 2010-2015 (1.43 [1.35-1.51]). Subgroup analyses supported our main findings. As PWID, CSW, and MSM are associated with HIV-1 recombinants, increased preventative measures and HIV-1 molecular surveillance are crucial within these key populations. PROSPERO [CRD42017067164].

Characteristics of genotype, drug resistance, and molecular transmission network among newly diagnosed HIV-1 infections in Shenzhen, China.

The HIV-1 pandemic has persisted for four decades, and poses a major challenge to global public health. Shenzhen, a city with large number of migrant populations in China, is suffering HIV-1 epidemic. It is necessary to continuously conduct the molecular surveillance among newly diagnosed HIV-1 patients in these migrant population. In this study, plasma samples of newly diagnosed and ART-naive HIV-1 infections were collected from Shenzhen city in China. The partial genes of HIV-1 gag and pol were amplified and sequenced for the analysis of genotype, drug resistance, and molecular transmission network. Ninety-one sequences of pol gene were obtained from newly diagnosed HIV-1 infections in Shenzhen, and seven HIV-1 subtypes were revealed in this investigation. Among them, the circulating recombinant form (CRF) 07_BC was the mostly frequent subtype (53.8%, 49/91), followed by CRF01_AE (20.9%, 19/91), CRF55_01B (9.9%, 9/91), unique recombinant forms (URFs) (8.8%, 8/91), B (3.3%, 3/91), CRF59_01B (2.2%, 2/91), and CRF08_BC (1.1%, 1/91). The overall prevalence of pretreatment drug resistance (PDR) was 23.1% (21/91), and 52.38% (11/21) of the PDR was specific for the nonnucleotide reverse transcriptase inhibitors (NNRTIs). Furthermore, a total of 3091 pol gene sequences were used to generate 19 molecular transmission clusters, and then one growing cluster, a new cluster, and a cluster with growth reactivation were identified. The result revealed that more sexual partner, CRF_07BC subtype, and seven amino acid deletions in gag p6 region might be the influencing factors associated with the high risk of transmission behavior. Compared with CRF01_AE subtype, CRF07_BC subtype strains were more likely to form clusters in molecular transmission network. This suggests that long-term surveillance of the HIV-1 molecular transmission should be a critical measure to achieve a precise intervention for controlling the spread of HIV-1 in China.

Genome mosaic structure of two novel HIV-1 recombinant forms (CRF01_AE/B) in men who have sex with men in Hebei, China

BackgroundHomosexual contact is the main route of human immunodeficiency virus type one (HIV-1) transmission in Cangzhou Prefecture, Hebei, China. Moreover, the number of circulating recombinant forms (CRFs) and unique recombinant forms (URFs) in this key population is ever increasing.MethodsIn this study, we identified two novel URFs (hcz0017 and hcz0045) from two men who have sex with men (MSM) based in Cangzhou Prefecture. Phylogenetic and recombinant breakpoint analyses, based on the near full-length genomes (NFLGs) of the two novel URFs, showed that they originated from a recombination between HIV-1 CRF01_AE and subtype B.ResultsHXB2 numbering revealed that the NFLGs of hcz0017 and hcz0045 each contained the following seven subregions: hcz0017: IB (790–1,171 nt), IICRF01_AE (1,172–2,022 nt), IIIB (2,023–4,469 nt), IVCRF01_AE (4,470–5,866 nt), VB (5,867–7,462 nt), VICRF01_AE (7,463–8,379 nt), VIIB (8,380–9,411 nt); hcz0045: ICRF01_AE (790–5,147 nt), IIB (5,148–5,614 nt), IIICRF01_AE (5,615–6,035 nt), IVB (6,036–6,241 nt), VCRF01_AE (6,242–7,325nt), VIB (7,326–8,254 nt), VIICRF01_AE (8,255–9,411 nt). Moreover, the two MSM from whom the novel URFs originated from were diagnosed as recently HIV-1-infected, suggesting that the high prevalence of HIV-1 among MSM was related to high-risk sexual activity such as unprotected anal sex and multiple sexual partners.ConclusionsOur results highlight the need to continually monitor HIV-1 diversity in Hebei and its neighboring provinces to achieve a more effective control of HIV-1 spread within the MSM community.

Genetic Diversity and Characteristics of Drug Resistance Among Treatment-Naive People Living with HIV in Xi'an, China.

The genetic diversity and genetic predisposition for drug resistance mutations are the primary features of human immunodeficiency virus type 1 (HIV-1), which could cause the incidence of failure of antiretroviral therapy (ART). This study investigates the distribution of various HIV-1 genotypes and the incidence of pretreatment drug resistance (PDR) in the antiretroviral-naive HIV-1 infected participants in Xi'an, China. In this study, a cross-sectional analysis was carried out at the Xi'an Eighth Hospital between January 2020 and December 2021 among newly-diagnosed ART-naive HIV-1 infected participants. A nested PCR technique was used for amplifying the target segment of 1.3 kb present in the pol gene that spanned the reverse transcriptase and the protease regions. HIV-1 genotypes and the PDR-associated mutations were identified using the Stanford HIV Drug Resistance Database. A total of 317 pol gene sequences were retrieved, amplified, and sequenced. The circulating recombinant form (CRF), CRF07_BC (51.7%) was seen to be the most prevalent HIV-1 genotype, followed by other genotypes like CRF01_AE (25.9%), B (14.2%), and CRF55_01B (4.7%). PDR was found in 18.3% of the population. The PDR mutation frequency in the non-nucleoside reverse transcriptase inhibitor (NNRTI) (16.1%) was significantly higher compared to that of the nucleoside reverse transcriptase inhibitor (NRTI) (4.4%) and the protease inhibitor (0.9%). V179D/E (both were 4.4%) was seen to be the most predominant type of NNRTI mutation. K65R and M184V (1.3%) were the most frequent NRTI-associated mutations. About half (48.3%) of the sequenced HIV-1 strains that had mutations could show a potential low-level NNRTI resistance owing to V179D/E. Multivariate regression analysis revealed one PDR mutation associated with subtype CRF01_AE (p=0.002) and CRF55_01B (p<0.001) as a higher risk mutation. Diverse and complex HIV-1 genotypes are distributed in Xi'an, China. Considering new evidence, it is necessary to screen for baseline HIV-1 drug resistance among the newly-diagnosed HIV-1 individuals.