HIV-1 genetic diversity and transmitted drug resistance among newly diagnosed HIV-1 individuals in Jiangmen, China.

Jiangmen is one of the Guangdong-Hong Kong-Macao Greater Bay Areas with frequent commercial intercourse, which is responsible for human immunodeficiency virus type 1 (HIV-1) rapid circulation and genetic evolution for recent years. As a novel HIV-1 second-generation recombinant was previously reported in Jiangmen but the systematic molecular epidemiological investigation was still unknown. A retrospective study on HIV-1 genotypic characteristics and the emergence of transmitted drug resistance in this region was necessary. A total of 224 newly diagnosed HIV-positive cases were randomly selected in Jiangmen City of Guangdong Province between 2018 and 2019. The partial gag (1080 bp), pol (840 bp), and env (460 bp) genes were amplified using nested polymerase chain reaction followed by sequencing. The phylogenetic and recombination analysis as well as HIV-1 drug resistance were performed to surveillance. Sexual transmission was determined to be the major risk factor in Jiangmen. Phylogenetic analysis detected the genotypic distribution as follows: CRF01_AE (36.65%,70 of 191), CRF07_BC (32.46%, 62 of 191), CRF08_BC (4.71%, 9 of 191), CRF55_01B (5.24%, 10 of 191), CRF59_01B (3.14%, 6 of 191), subtype B (4.71%, 9 of 191), subtype C (1.05%, 2 of 191) as well as unique recombinant forms (12.04%, 23 of 191) consisted of seven recombinant patterns, which originated from multiple regions of China. Low-level prevalence of Surveillance Drug Resistance Mutations (2.1%) were predicted but drug-resistant mutations showed at a high level (15.4%) especially mutations in RT gene at position 179 were found to be the most frequent in the therapy-naïve population. Our study highlighted the critical importance of monitoring the emerge of recombinant strains among newly diagnosed HIV-1 individuals along with drug resistance regularly to prevent multi-channel introduction and breakout of new HIV strains.

Multiple HIV-1/M + HIV-1/O dual infections and new HIV-1/MO inter-group recombinant forms detected in Cameroon.

BACKGROUND: Due to the prevalence of HIV-1 group M and the endemicity of HIV-1 group O infections in Cameroon, patients may be infected with both viruses and/or with HIV-1/MO recombinant forms. Such atypical infections may be deleterious in terms of diagnosis and therapeutic management due to the high divergence of HIV-1/O. The aim of this study was to identify prospectively such atypical infections in Cameroon. RESULTS: Based on serological screening by env-V3 serotyping and a molecular strategy using group-specific (RT)-PCRs, we identified 10 Cameroonian patients harboring three different profiles of infection: (1) 4 HIV-1/M + O dual infections without evidence of recombinant; (2) 5 recombinants associated with one or both parental strains; and (3) 1 new recombinant form without parental strains. CONCLUSIONS: This work highlights the dynamic co-evolution of these two HIV groups in Cameroon that could lead to the emergence of a circulating recombinant form MO, and the need for accurate identification of such atypical infections for precise diagnosis, virological monitoring and therapeutic management with adapted tools.

Comparative Evaluation of Subtyping Tools for Surveillance of Newly Emerging HIV-1 Strains.

HIV-1 non-B subtypes/circulating recombinant forms (CRFs) are increasing worldwide. Since subtype identification can be clinically relevant, we assessed the added value in HIV-1 subtyping using updated molecular phylogeny (Mphy) and the performance of routinely used automated tools. Updated Mphy (2015 updated reference sequences), used as a gold standard, was performed to subtype 13,116 HIV-1 protease/reverse transcriptase sequences and then compared with previous Mphy (reference sequences until 2014) and with COMET, REGA, SCUEAL, and Stanford subtyping tools. Updated Mphy classified subtype B as the most prevalent (73.4%), followed by CRF02_AG (7.9%), C (4.6%), F1 (3.4%), A1 (2.2%), G (1.6%), CRF12_BF (1.2%), and other subtypes (5.7%). A 2.3% proportion of sequences were reassigned as different subtypes or CRFs because of misclassification by previous Mphy. Overall, the tool most concordant with updated Mphy was Stanford-v8.1 (95.4%), followed by COMET (93.8%), REGA-v3 (92.5%), Stanford-old (91.1%), and SCUEAL (85.9%). All the tools had a high sensitivity (≥98.0%) and specificity (≥95.7%) for subtype B. Regarding non-B subtypes, Stanford-v8.1 was the best tool for C, D, and F subtypes and for CRFs 01, 02, 06, 11, and 36 (sensitivity, ≥92.6%; specificity, ≥99.1%). A1 and G subtypes were better classified by COMET (92.3%) and REGA-v3 (98.6%), respectively. Our findings confirm Mphy as the gold standard for accurate HIV-1 subtyping, although Stanford-v8.1, occasionally combined with COMET or REGA-v3, represents an effective subtyping approach in clinical settings. Periodic updating of HIV-1 reference sequences is fundamental to improving subtype characterization in the context of an effective epidemiological surveillance of non-B strains.

Molecular epidemiology is becoming complex under the dynamic HIV prevalence: The perspective from Harbin, China.

Unlike most areas of China, HIV transmission via men who have sex with men (MSM) is increasing rapidly, and has become the main route of HIV transmission in Harbin city. The purpose of the current study was to elaborate the molecular epidemiologic characteristics of the new HIV epidemic. Eighty-one HIV-1 gag gene sequences (HXB2:806-1861) from local HIV infections were isolated; CRF01_AE predominated among HIV infections (71.6%), followed by subtype B (16.5%), CRF07_BC (6.2%), and unique recombinant strains (URFs; 6.2%). URFs were most often identified in the MSM population, which consisted of a recombination of CRF01_AE with subtype B or CRF07_BC. Six clusters were formed in this analysis; clusters I and II mainly circulated in southwest China. Clusters III and IV mainly circulated in southwest, southeast, and central China. Clusters V and VI mainly circulated in north and northeast China. Clusters III and IV may facilitate the transmission of the CRF01_AE strain from the southwest to the north and northeast regions of China. HIV subtypes are becoming diverse with the persistent epidemic in this geographic region. In brief, our results indicate that the molecular epidemiology of HIV is trending to be more complex. Thus, timely molecular epidemiologic supervision of HIV is necessary, especially for the MSM population.

The evolution of HIV-1 group M genetic variability in Southern Cameroon is characterized by several emerging recombinant forms of CRF02_AG and viruses with drug resistance mutations.

The HIV epidemic in Cameroon is marked by a broad genetic diversity dominated by circulating recombinant forms (CRFs). Studies performed more than a decade ago in urban settings of Southern Cameroon revealed a dominance of the CRF02_AG and clade A variants in >90% of the infected subjects; however, little is known about the evolving viral variants circulating in this region. To document circulating HIV viral diversity, four regions of the viral genome (gag, PR, reverse transcriptase, env) in 116 HIV-1 positive individuals in Limbe, Southern Cameroon, were PCR-amplified. Sequences obtained at the RT and protease regions were analyzed for mutations that conferred drug resistance using the Stanford Drug Resistance Database. The present study reveals a broad genetic diversity characterized by several unique recombinant forms (URF) accounting for 36% of infections, 48.6% of patients infected with CRF02_AG, and the emergence of CRF22_01A1 in 7.2% of patients. Three out of 15 (20%) treated patients and 13 out of 93 (13.9%) drug naïve patients harbor drug resistance mutations to RT inhibitors, while 3.2% of drug naïve patients harbor drug resistance mutations associated with protease inhibitors. The high proportion (13.9%) of drug resistance mutations among the drug naïve patients reveals the ongoing transmission of these viruses in this region of Cameroon and highlights the need for drug resistance testing before starting treatment for patients infected with HIV-1.

Recombination and evolutionary dynamics of human echovirus 6.

Enterovirus (EV) infections are associated with a wide array of often severe disease presentations including aseptic meningitis, encephalitis, and acute flaccid paralysis. Surveillance for polioviruses and other EVs is therefore important as a public health measure both for patient management and epidemiological studies. From 1988 to 2008, echovirus (E) 30 was the predominant genotype in Spain (33.7% of the total typed EVs). E6 was also endemic throughout this period although isolated less frequently (12.5%). In 2009, however, a substantial increase in the incidence of E6 was detected (60%), displacing E30 type (2%). To investigate the evolution and recombination in the epidemiology and transmission of E6 in Spain, a genetic analysis in VP1 and 3Dpol regions of 67 Spanish strains collected during the period 2004-2010 was performed. All VP1 sequences clustered monophyletically in the assigned genogroup C, subgroup 9, currently the predominant circulating strains identified in Europe and elsewhere in the last 10 years. 3Dpol sequences were interspersed with other species B EVs resulting from several recombination events that generated at least 12 different recombinant forms (RFs) among study samples. These showed typically minimal divergence in VP1. The co-circulation of different lineages of E6 in the same geographical area associated with its mainly endemic pattern of transmission may have contributed to the extremely short estimated half-life of E6 RFs (0.87 years). This pattern contrasts markedly with other species B EVs and EV71 where VP1 lineage expansion and extinction occurred in step with defined recombination events and periodic changes in incidence.

Identification of a new HIV-1 circulating recombinant form (CRF159_01103) derived from CRF103_01B and CRF01_AE in Hebei Province, China.

Recombinant HIV-1 genomes identified in three or more epidemiological unrelated individuals are defined as circulating recombinant forms (CRFs). CRFs can further recombine with other pure subtypes or recombinants to produce secondary recombinants. In this study, a new HIV-1 intersubtype CRF, designated CRF159_01103, isolated from three men who have sex with men with no epidemiological linkage, was identified in Baoding city, Hebei Province, China. CRF159_01103 was derived from CRF103_01B and CRF01_AE. Bayesian molecular clock analysis was performed on the CRF01-AE and CRF103_01B regions of CRF159_01103. The time of origin of CRF159_01103 was predicted to be 2018-2019, indicating that it is a recent recombinant virus. The emergence of CRF159_01103 has increased the complexity of the HIV-1 epidemic in Hebei Province.

Population-based nanopore sequencing of the HIV-1 pangenome to identify drug resistance mutations.

HIV-1 drug resistance genotypic tests have primarily been performed by Sanger sequencing of gene segments encoding different drug target proteins. Since the number of targets has increased with the addition of a new class of antiretroviral drugs, a simple high-throughput system for assessing nucleotide sequences throughout the HIV-1 genome is required. Here, we developed a new solution using nanopore sequencing of viral pangenomes amplified by PCR. Benchmark tests using HIV-1 molecular clones demonstrated an accuracy of up to 99.9%. In addition, validation tests of our protocol in 106 clinical samples demonstrated high concordance of drug resistance and tropism genotypes (92.5% and 98.1%, respectively) between the nanopore sequencing-based results and archived clinical determinations made based on Sanger sequencing data. These results suggest that our new approach will be a powerful solution for the comprehensive survey of HIV-1 drug resistance mutations in clinical settings.

Synergetic association between coxsackievirus A16 genotype evolution and recombinant form shifts.

Coxsackievirus A16 (CVA16) is a major pathogen that causes hand, foot, and mouth disease (HFMD). The recombination form (RF) shifts and global transmission dynamics of CVA16 remain unknown. In this retrospective study, global sequences of CVA16 were retrieved from the GenBank database and analyzed using comprehensive phylogenetic inference, RF surveys, and population structure. A total of 1,663 sequences were collected, forming a 442-sequences dataset for VP1 coding region analysis and a 345-sequences dataset for RF identification. Based on the VP1 coding region used for serotyping, three genotypes (A, B, and D), two subgenotypes of genotype B (B1 and B2), and three clusters of subgenotype B1 (B1a, B1b, and B1c) were identified. Cluster B1b has dominated the global epidemics, B2 disappeared in 2000, and D is an emerging genotype dating back to August 2002. Globally, four oscillation phases of CVA16 evolution, with a peak in 2013, and three migration pathways were identified. Europe, China, and Japan have served as the seeds for the global transmission of CVA16. Based on the 3D coding region of the RFs, five clusters of RFs (RF-A to -E) were identified. The shift in RFs from RF-B and RF-C to RF-D was accompanied by a change in genotype from B2 to B1a and B1c and then to B1b. In conclusion, the evolution and population dynamics of CVA16, especially the coevolution of 3D and VP1 genes, revealed that genotype evolution and RF replacement were synergistic rather than stochastic.

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.

Characterization of two novel HIV-1 second-generation recombinants (CRF01_AE/CRF07_BC) identified in Hebei Province, China.

Introduction: The unique recombinant forms (URFs) of HIV-1 consist of a mixture of subtypes, and each URF has a unique breakpoint. In this study, we identified the near fulllength genome (NFLG) sequences of two novel HIV-1 URFs (Sample ID: BDD034A and BDL060) isolated during HIV-1 molecular surveillance in 2022 in Baoding city, Hebei Province, China. Methods: The two sequences were aligned with subtype reference sequences and CRFs from China using MAFFT v7.0, and the alignments were adjusted manually using BioEdit (v7.2.5.0). Phylogenetic and subregion trees were constructed using MEGA11 with the neighbor-joining (N-J) method. Recombination breakpoints were identified by SimPlot (v3.5.1) based on Bootscan analyses. Results: Recombinant breakpoint analysis revealed that the NFLGs of BDD034A and BDL060 were composed of CRF01_AE and CRF07_BC, containing seven segments, respectively. For BDD034A, three CRF01_AE fragments were inserted into the CRF07_BC main framework, whereas for BDL060, three CRF07_BC fragments were inserted into the CRF01_AE main framework. Discussion: The emergence of the CRF01_AE/CRF07_BC recombinant strains indicates that HIV-1 co-infection is common. The increasing genetic complexity of the HIV-1 epidemic in China warrants continued investigation.

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

Introduction: 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. Methods: 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. Results: 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. Conclusion: 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.

Viruses Previously Identified in Brazil as Belonging to HIV-1 CRF72_BF1 Represent Two Closely Related Circulating Recombinant Forms, One of Which, Designated CRF122_BF1, Is Also Circulating in Spain.

Circulating recombinant forms (CRFs) are important components of the HIV-1 pandemic. Those derived from recombination between subtype B and subsubtype F1, with 18 reported, most of them of South American origin, are among the most diverse. In this study, we identified a HIV-1 BF1 recombinant cluster that is expanding in Spain, transmitted mainly via heterosexual contact, which, analyzed in near full-length genomes in four viruses, exhibited a coincident BF1 mosaic structure, with 12 breakpoints, that fully coincided with that of two viruses (10BR_MG003 and 10BR_MG005) from Brazil, previously classified as CRF72_BF1. The three remaining Brazilian viruses (10BR_MG002, 10BR_MG004, and 10BR_MG008) previously identified as CRF72_BF1 exhibited mosaic structures highly similar, but not identical, to that of the Spanish viruses and to 10BR_MG003 and 10BR_MG005, with discrepant subtypes in two short genome segments, located in pol and gp120env. Based on these results, we propose that the five viruses from Brazil previously identified as CRF72_BF1 actually belong to two closely related CRFs, one comprising 10BR_MG002, 10BR_MG004, and 10BR_MG008, which keep their CRF72_BF1 designation, and the other, designated CRF122_BF1, comprising 10BR_MG003, 10BR_MG005, and the viruses of the identified Spanish cluster. Three other BF1 recombinant genomes, two from Brazil and one from Italy, previously identified as unique recombinant forms, were classified as CRF72_BF1. CRF122_BF1, but not CRF72_BF1, was associated with protease L89M substitution, which was reported to contribute to antiretroviral drug resistance. Phylodynamic analyses estimate the emergence of CRF122_BF1 in Brazil around 1987. Given their close phylogenetic relationship and similar structures, the grouping of CRF72_BF1 and CRF122_BF1 in a CRF family is proposed.

Characterization of a novel HIV-1 circulating recombinant form, CRF91_cpx, comprising CRF02_AG, G, J, and U, mostly among men who have sex with men.

Prospective molecular studies of HIV-1 pol region (2253-5250 in HXB2 genome) sequences from sequenced samples of 269 HIV-1-infected patients in Cyprus (2017-2021) revealed a transmission cluster of 14 unknown HIV-1 recombinants that were not classified as previously established CRFs. The earliest recombinant was collected in September 2017, and the transmission cluster continued to grow until November 2020. Near full-length HIV-1 genome sequences of the 11 of the 14 recombinants were successfully obtained (790-8795 in HXB2 genome) and aligned against a reference dataset of HIV-1 subtypes and CRFs. We employed MEGAX for maximum-likelihood tree construction (GTR model, 1000 bootstrap replicates), Cluster-Picker for phylogenetic clustering analysis (genetic distance ≤0.045, bootstrap support value ≥70%), and REGA-3.0 for subtype determination. Bootscan and similarity plot analyses (sliding window of 400 nucleotides overlapped by 40 nucleotides) were conducted using SimPlot-v3.5.1, and subregion confirmatory neighbour-joining tree analyses were conducted using MEGAX (Kimura two-parameter model, 1000 bootstrap replicates, ≥70% bootstrap-support value). Exclusive clustering of the HIV-1 recombinants revealed their uniqueness. The recombination analyses illustrated the same unique mosaic pattern with six putative intersubtype recombination breakpoints, seven fragments of subtypes CRF02_AG, G, J and an unclassified fragment. We conclusively characterized the mosaic structure of the novel HIV-1 CRF, named CRF91_cpx, by the Los Alamos HIV Sequence Database. Additionally, we identified a URF of CRF91_cpx with two additional recombination sites, generated by a recombination event between subtype B and CRF91_cpx. Since the identification of CRF91_cpx, two additional patient samples have been entered into the CRF91_cpx transmission cluster, demonstrating active growth.

Identification of two novel HIV-1 circulating recombinant forms of CRF111_01C and CRF116_0108 in southwestern Yunnan, China.

Yunnan, the region hardest hit by HIV/AIDS in China, is also an area with the most abundant HIV-1 genetic diversity. A large number of novel HIV-1 circulating recombinant forms (CRFs) and unique recombinants were identified among injection drug users in Yunnan; however, few were found among sexual contacts. Here, we obtained 15 near full-length genome sequences (NFLGs) from HIV-1 seropositive heterosexual contacts in Yunnan who received antiretroviral therapy during the period from 2014 to 2016. Phylogenetic analysis showed that six NFLGs belonged to CRF01_AE (n = 3) and CRF106_cpx (n = 3), and the other nine sequences were novel inter-subtype recombinants. Of the recombinants, two novel CRFs (CRF111_01 C (n = 4) and CRF116_0108 (n = 4)) and one CRF106_cpx variant (n = 1) were identified. CRF111_01 C had a CRF01_AE backbone with seven subtype C fragments inserted into the gag, pol, vif, env, nef and 3'LTR regions. CRF116_0108 had a CRF08_BC backbone with a CRF01_AE fragment inserted into the pol, tat, rev, vif, vpr, vpu and env regions. Phylogeographic analyses estimated that CRF111_01 C and CRF116_0108 originated approximately 1995.7-1998.6 and 1991.7-1993.7, respectively. These identifications of two novel HIV-1 CRFs highlighted the importance of continuous surveillance in heterosexual contacts and other high-risk groups in this region and the surrounding regions.

Detection of Patient HIV-1 Drug Resistance Mutations in Russia's Northwestern Federal District in Patients with Treatment Failure.

Highly active antiretroviral therapy (HAART) is currently a combination of three (less frequently four) antiretroviral drugs; these target pathways involved in various stages of HIV replication in the body. Treatment failure is a problem facing doctors and patients using HAART. The most common cause of therapeutic failure is the development of HIV drug resistance. The emergence of resistance is associated with processes involving mutation occurring in the viral genome under the influence of evolutionary factors. Sequencing reactions were performed using the AmpliSens HIV Resist-Seq. Assembly of consensus sequences from fragments obtained during sequencing was carried out using Unipro UGENE softwar. Isolate genotyping was performed using the MEGA-X software with the Neighbor-joining algorithm. According to the analysis, 72.05% of patients had at least one significant mutation associated with drug resistance for the corresponding viral subtype. HIV-1 A6 remains the predominant HIV-1 genetic variant in Russia's Northwestern Federal District. Among samples with drug resistance mutations, in all cases, mutations associated with pharmacological resistance to two or three drug groups were found. Given the high incidence of resistance mutations in patients on ineffective ART, surveillance of HIV-1 drug resistance, in both ART-receiving and ART-naive individuals, appears necessary. A lack of vigilance and control measures may lead to the spread of primary ART-resistant HIV strains.

Multiple CRF01_AE/CRF07_BC Recombinants Enhanced the HIV-1 Epidemic Complexity Among MSM in Shenyang City, Northeast China.

The transmission of Unique Recombinant Forms (URFs) has complicated the molecular epidemic of HIV-1. This increasing genetic diversity has implications for prevention surveillance, diagnosis, and vaccine design. In this study, we characterized the HIV-1 URFs from 135 newly diagnosed HIV-1 infected cases between 2016 and 2020 in Shenyang, northeast China and analyzed the evolutionary relationship of them by phylogenetic and recombination approaches. Among 135 URFs, we found that the CRF01_AE/CRF07_BC recombinants were the most common (81.5%, 110/135), followed by CRF01_AE/B (11.9%, 16/135), B/C (3.7%, 5/135), and others (3.0%, 4/135). 94.8% (128/135) of patients infected by URFs were through homosexual contact. Among 110 URFs_0107, 60 (54.5%) formed 11 subclusters (branch support value = 1) and shared the consistent recombination structure, respectively. Four subclusters have caused small-scale spread among different high-risk populations. Although the recombination structures of URFs_0107 are various, the hotspots of recombinants gathered between position 2,508 and 2,627 (relative to the HXB2 position). Moreover, the CRF07_BC and CRF01AE fragments of URFs_0107 were mainly derived from the MSM population. In brief, our results reveal the complex recombinant modes and the high transmission risk of URFs_0107, which calls for more attention on the new URFs_0107 monitoring and strict control in the areas led by homosexual transmission route.

Molecular Epidemiology of HIV-1 in Eastern Europe and Russia.

The HIV epidemic in Eastern Europe and Russia is large and not well-controlled. To describe the more recent molecular epidemiology of HIV-1, transmitted drug resistance, and the relationship between the epidemics in this region, we sequenced the protease and reverse transcriptase genes of HIV-1 from 812 people living with HIV from Ukraine (n = 191), Georgia (n = 201), and Russia (n = 420) before the initiation of antiretroviral therapy. In 190 Ukrainian patients, the integrase gene sequence was also determined. The most reported route of transmission was heterosexual contact, followed by intravenous drug use, and men having sex with men (MSM). Several pre-existing drug resistance mutations were found against non-nucleoside reverse transcriptase inhibitors (RTIs) (n = 103), protease inhibitors (n = 11), and nucleoside analogue RTIs (n = 12), mostly polymorphic mutations or revertants. In the integrase gene, four strains with accessory integrase strand transfer inhibitor mutations were identified. Sub-subtype A6 caused most of the infections (713/812; 87.8%) in all three countries, including in MSM. In contrast to earlier studies, no clear clusters related to the route of transmission were identified, indicating that, within the region, the exchange of viruses among the different risk groups may occur more often than earlier reported.

HIV-1 Circulating Recombinant Forms (CRFs) and Unique Recombinant Forms (URFs) in Israel, 2010-2018.

Monitoring HIV-1 circulating recombinant forms (CRFs) and unique recombinant forms (URFs) is important for disease surveillance. Recombination may affect prevention efforts and interfere with the diagnosis and treatment of HIV-1 infection. Here, we characterized the epidemiology of HIV-1 CRFs and URFs in Israel. Partial pol sequences from treatment naïve patients diagnosed in 2010−2018 were assessed using the recombinant identification program (RIP), the recombinant detection program (RDP5), and using the maximum-likelihood phylogenetic method, using 410 reference sequences obtained from the Los Alamos database. CRFs and URFs were identified in 11% (213/1940) of all sequenced cases. The median age at diagnosis was 38 (30−47) years, 61% originated from Israel, and 82% were male. The most common were CRF02_AG (30.5%), CRF01_AE (16.9%), and the more complex forms CRF01_AE/CRF02_AG/A3 (10.8%) and B/F1 (7%). A significant increase in their overall proportion was observed in recent years (8.1% in 2010−2012, 20.3% in 2016−2018, p < 0.001). This increase was most prominent in individuals carrying CRF02_AG (2.5% in 2010−2015, 9.8% in 2016−2018, p < 0.001). Men who have sex with men (MSM) was the most common risk group; however, those infected with the secondary recombinant CRF02_AG/A6 were mainly injecting drug users (IDUs). The most common resistance mutations were K103N (5/213, 2.3%) and E138A (18/213, 8.5%) in the reverse transcriptase. Only E138A was more frequent in the recombinants compared with the classic subtypes and was significantly associated with a specific secondary CRF, CRF02_AG/A4. We concluded that CRFs and URFs were mainly detected in Israeli-born MSM and that an increase in the overall proportion of such HIV-1 sequences could be observed in more recent years.

Non-B variants of HIV-1 in San Francisco, California.

The HIV-1 epidemic in the US has historically been dominated by subtype B. HIV subtype diversity has not been extensively examined in most US cities to determine whether non-B variants have become established, as has been observed in many other global regions. We describe the diversity of non-B variants and present evidence of local transmission of non-B HIV in San Francisco. Viral sequences collected from patients between 2000 and 2016 were matched to the San Francisco HIV/AIDS case registry. HIV subtype was determined using COMET. Phylogenies were reconstructed using the pol region of subtypes A, C, D, G, CRF01_AE, CRF02_AG, and CRF07_BC, with reference sequences from the LANL HIV database. Associations of non-B subtypes and circulating recombinant forms (CRFs) with patient characteristics were assessed using multivariable logistic regression. Out of 11,381 sequences, 10,669 were from 7235 registry cases, of which 141 (2%) had non-B subtypes and CRFs and 72 (1%) had unique recombinant forms. CRF01_AE (0.8%) and subtype C (0.5%) were the most prevalent non-B forms. The frequency of non-B subtypes and CRFs increased in San Francisco during years 2000-2016. Out of 146 transmission events involving non-B study sequences, 18% indicated local transmission within the study population and 74% appeared to be inward migration of the virus. Compared to 7016 cases with only subtype B, 141 cases with non-B sequences were more likely to be of non-US country of birth (aOR = 11.02; p < 0.001), of Asian/Pacific-Islander race/ethnicity (aOR = 3.17; p < 0.001), and diagnosed after 2009 (aOR = 4.81; p < 0.001). Results suggest that most non-B infections were likely acquired outside the US and that local transmission of non-B forms has occurred but so far has not produced extensive transmission networks. Thus, non-B variants were not widely established in San Francisco, an observation that differs from cities worldwide with more diverse epidemics.