PRESTIGIO RING "a 59-year-old man with multidrug resistant HIV-1 infection failing a regimen including dolutegravir, rilpivirine, atazanavir/cobicistat: successful treatment tailoring based on genotypic and phenotypic resistance tests".

Management of virological failure in heavily treatment-experienced people with multidrug-resistant (MDR) HIV infection is a serious clinical challenge. New drugs with novel mechanisms of action have recently been approved, and their use has improved the outcome of subjects with limited treatment options (LTO). In this setting, the choice of antiretroviral therapy (ART) should be tailored based on the pattern of resistance, treatment history and patients' individual characteristics. While genotypic resistance testing is the reference method for analysing residual drug susceptibility, phenotypic resistance testing can provide additional support when facing LTO. Herein, we present the case of a patient with MDR HIV-1 infection on virological failure enrolled in the PRESTIGIO Registry. The salvage ART regimen, which included drugs with novel mechanisms of action (MoA), was tailored to the patient's clinical characteristics and on the resistance pattern explored with genotypic and phenotypic investigation, allowing the achievement of viro-immunological success. The use of recently approved drugs with novel MoA, combined with an optimized background regimen, may also achieve virological suppression in people with LTO.

Genetic and antiretroviral drug resistance mutations analysis of reverse transcriptase and protease gene from Pakistani people living with HIV-1.

BACKGROUND: Antiretroviral therapy (ART) effectiveness is compromised by the emergence of HIV drug resistance mutations (DRM) and can lead to the failure of ART. Apart from intrinsic viral factors, non-compliance with drugs and/or the use of sub-optimum therapy can lead to the emergence of DRMs. In Pakistan HIV currently exists as a concentrated epidemic, however, ART coverage is very low, and drug adherence is poor. ART is selected assuming without baseline genotyping. Pakistan has recently seen a rise in treatment failures, but the country's actual burden of DRM is still unknown. In this study, we perform the genetic and drug resistance analysis of the pol gene from Pakistani HIV-positive ART-naïve and ART-experienced individuals. METHODS: In this study, HIV-1 pol was sequenced from 146 HIV-1 positive individuals, divided into ART-naïve (n = 37) and ART-experienced (n = 109). The sequences were also used to determine HIV-1 subtypes, the prevalence of DRM, and pol genetic variability. RESULTS: DRM analysis identified numerous DRMs against reverse transcriptase inhibitors in both ART-naïve and ART-experienced groups, including a few that are classified as rare. Additionally, the ART-experienced group showed mutations associated with resistance to protease inhibitors. Genetic analysis showed negative selection pressure in both groups, but a higher rate of evolution in the ART-naïve group. CONCLUSION: High prevalence of DRMs, especially against previous first-line treatment in ART- naïve and the accumulation of DRMs in ART-experienced groups is concerning and warrants that a more extensive DRM survey be carried out to inform first-line and second-line ART regimen recommendations.

Week 96 Genotypic and Phenotypic Results of the Fostemsavir Phase 3 BRIGHTE Study in Heavily Treatment-Experienced Adults Living with Multidrug-Resistant HIV-1.

In the phase 3 BRIGHTE study in heavily treatment-experienced adults with multidrug-resistant HIV-1, fostemsavir plus optimized background therapy (OBT) resulted in sustained rates of virologic suppression through 96 weeks. HIV-1 RNA <40 copies/mL was achieved in 163/272 (60%) Randomized Cohort (RC) participants (with 1 or 2 remaining approved fully active antiretrovirals) and 37/99 (37%) Non-randomized Cohort (NRC) participants (with 0 fully active antiretrovirals). Here we report genotypic and phenotypic analyses of HIV-1 samples from 63/272 (23%) RC participants and 49/99 (49%) NRC participants who met protocol-defined virologic failure (PDVF) criteria through Week 96. The incidence of PDVF was as expected in this difficult-to-treat patient population and, among RC participants, was comparable regardless of the presence of predefined gp120 amino acid substitutions that potentially influence phenotypic susceptibility to temsavir (S375H/I/M/N/T, M426L, M434I, M475I) or baseline temsavir 50% inhibitory concentration fold change (IC50 FC). The incidence of PDVF was lower among participants with higher overall susceptibility score to newly used antiretrovirals (OSS-new), indicating that OSS-new may be a preferred predictor of virologic outcome in heavily treatment-experienced individuals. Predefined gp120 substitutions, most commonly M426L or S375N, were emergent on treatment in 24/50 (48%) RC and 33/44 (75%) NRC participants with PDVF, with related increases in temsavir IC50 FC. In BRIGHTE, PDVF was not consistently associated with treatment-emergent genotypic or phenotypic changes in susceptibility to temsavir or to antiretrovirals in the initial OBT. Further research will be needed to identify which factors are most likely to contribute to virologic failure in this heavily treatment-experienced population (ClinicalTrials.gov, NCT02362503).

The transmission of drug-resistant strains of HIV in heterosexual populations based on genetic sequences.

BACKGROUND: China's National Free Antiretroviral Treatment Program (NFATP) has substantially reduced morbidity and HIV/AIDS incidence since 2003. However, HIV resistance to antiretroviral drugs (ARVs) has been a major challenge for the current treatment of HIV/AIDS in China. METHODS: In the current study, we established a nested dynamic model to predict the multi-drug resistance dynamics of HIV among the heterosexual population and evaluated the impact of intervention measures on the transmission of drug resistance. We obtained an effective reproductive number [Formula: see text] from each sub-model held at different stages of the dynamic model. Meanwhile, we applied Bayesian phylogenetic methods to infer the weighted average effective reproductive number [Formula: see text] from four HIV subtypes that sampled from 912 HIV-positive patients in China. It is an original and innovative method by fitting [Formula: see text] to [Formula: see text] by Markov Chain Monte Carlo (MCMC) to generate unknown parameters in [Formula: see text]. RESULTS: By analyzing the HIV gene sequences, we inferred that the most recent common ancestor of CRF01AE, CRF07BC, CRF08BC, and CRFBC dated from 1994, 1990, 1993 and 1990, respectively. The weighted average effective reproductive number [Formula: see text] dropped from 1.95 in 1994 to 1.73 in 2018. Considering different interventions, we used a macro dynamic model to predict the trend of HIV resistance. The results show that the number of new infections and total drug resistance under the baseline parameter (S1) are 253,422 and 213,250 in 2025, respectively. Comparing with the numbers under the target treatment rate (S2), they were 219,717 and 236,890, respectively. However, under the ideal treatment target (S3, the treatment rate reaches 90% and the treatment success rate reaches 90%), the number of new infections shows a declining trend and will decrease to 46,559 by 2025. Compared with S1 and S2, the total number of resistance also decreased to 160,899 in 2025. CONCLUSION: With the promotion of NFATP in China, HIV resistance to ARVs is inevitable. The strategy of increasing the treatment rate would not only ineffectively curb the epidemic, but also deteriorate drug resistance issue. Whereas, a combination of intervention strategies (the treatment rate reaches 90% and the treatment success rate reaches 90%) can greatly reduce both infection and drug resistance rate than applying one strategy alone.

Understanding patterns of HIV multi-drug resistance through models of temporal and spatial drug heterogeneity.

Triple-drug therapies have transformed HIV from a fatal condition to a chronic one. These therapies should prevent HIV drug resistance evolution, because one or more drugs suppress any partially resistant viruses. In practice, such therapies drastically reduced, but did not eliminate, resistance evolution. In this article, we reanalyze published data from an evolutionary perspective and demonstrate several intriguing patterns about HIV resistance evolution - resistance evolves (1) even after years on successful therapy, (2) sequentially, often via one mutation at a time and (3) in a partially predictable order. We describe how these observations might emerge under two models of HIV drugs varying in space or time. Despite decades of work in this area, much opportunity remains to create models with realistic parameters for three drugs, and to match model outcomes to resistance rates and genetic patterns from individuals on triple-drug therapy. Further, lessons from HIV may inform other systems.

Functional Insights into Silymarin as an Antiviral Agent against Enterovirus A71 (EV-A71).

Enterovirus A71 (EV-A71) is a major neurovirulent agent capable of causing severe hand, foot and mouth disease (HFMD) associated with neurological complications and death. Currently, no FDA-approved antiviral is available for the treatment of EV-A71 infections. The flavonoid silymarin was shown to exert virucidal effects, but the binding site on the capsid was unknown. In this study, the ligand interacting site of silymarin was determined in silico and validated in vitro. Moreover, the potential of EV-A71 to develop resistance against silymarin was further evaluated. Molecular docking of silymarin with the capsid of EV-A71 indicated that silymarin binds to viral protein 1 (VP1) of EV-A71, specifically at the GH loop of VP1. The in vitro binding of silymarin with VP1 of EV-A71 was validated using recombinant VP1 through ELISA competitive binding assay. Continuous passaging of EV-A71 in the presence of silymarin resulted in the emergence of a mutant carrying a substitution of isoleucine by threonine (I97T) at position 97 of the BC loop of EV-A71. The mutation was speculated to overcome the inhibitory effects of silymarin. This study provides functional insights into the underlying mechanism of EV-A71 inhibition by silymarin, but warrants further in vivo evaluation before being developed as a potential therapeutic agent.

Failure on voxilaprevir, velpatasvir, sofosbuvir and efficacy of rescue therapy.

BACKGROUND & AIMS: There are limited data on patients with chronic HCV infection in whom combination voxilaprevir (VOX), velpatasvir (VEL), sofosbuvir (SOF) retreatment fails. Thus, we aimed to assess treatment failure and rescue treatment options in these patients. METHODS: Samples from 40 patients with HCV genotypes (GT) 1-4 in whom VOX/VEL/SOF retreatment failed were collected within the European Resistance Study Group. Population-based resistance analyses were conducted and clinical parameters and retreatment efficacies were evaluated retrospectively in 22 patients. RESULTS: Most VOX/VEL/SOF failure patients were infected with HCV GT3a (n = 18, 45%) or GT1a (n = 11, 28%) and had cirrhosis (n = 28, 70%). Previous treatments included an NS3-inhibitor (30%), an NS5A-inhibitor (100%) and SOF (85%). Baseline RAS data from a subgroup of patients before VOX/VEL/SOF retreatment (78%) showed few NS3 RASs apart from Q80K in GT1a (40%), typical NS5A RAS patterns in most patients (74%) and no S282T in NS5B. Sequencing after VOX/VEL/SOF failure was available in 98% of patients and showed only minor changes for NS3 and NS5A RASs. In 22 patients, rescue treatment was initiated with glecaprevir, pibrentasvir alone (n = 2) or with SOF±ribavirin (n = 15), VOX/VEL/SOF±ribavirin (n = 4) or VEL/SOF and ribavirin (n = 1) for 12 to 24 weeks. Sustained virologic response was achieved in 17/21 (81%) patients with a final treatment outcome. Of these, 2 GT3a-infected patients had virologic failure after rescue treatment with VEL/SOF or glecaprevir/pibrentasvir+SOF+ribavirin, and 2 patients with cirrhosis died during treatment or before reaching SVR12. CONCLUSIONS: VOX/VEL/SOF failure was mainly observed in HCV GT3- and GT1a-infected patients with cirrhosis and was not associated with specific RAS patterns within NS3, NS5A or NS5B target regions. Rescue treatment with multiple targeted therapies was effective in most patients. LAY SUMMARY: The advent of direct-acting antivirals has enabled the effective cure of chronic hepatitis C in most patients. However, treatment failure occurs in some patients, who are often retreated with a combination regimen called VOX/VEL/SOF, which is associated with very high rates of cure. However, VOX/VEL/SOF retreatment also fails in some patients. Herein, we analysed samples from patients in whom VOX/VEL/SOF retreatment failed and we assessed the efficacy of different rescue therapies, showing that rescue treatment is effective in most patients (81%).

Genomic characterization of multidrug-resistant ESBL-producing Escherichia coli ST58 causing fatal colibacillosis in critically endangered Brazilian merganser (Mergus octosetaceus).

Even though antimicrobial-resistant bacteria have begun to be detected in wildlife, raising important issues related to their transmission and persistence of clinically important pathogens in the environment, little is known about the role of these bacteria on wildlife health, especially on endangered species. The Brazilian merganser (Mergus octosetaceus) is one of the most threatened waterfowl in the world, classified as Critically Endangered by the International Union for Conservation of Nature. In 2019, a fatal case of sepsis was diagnosed in an 8-day-old Brazilian merganser inhabiting a zoological park. At necropsy, major gross lesions were pulmonary and hepatic congestion. Using microbiologic and genomic methods, we identified a multidrug-resistant (MDR) extended-spectrum ß-lactamase (ESBL) CTX-M-8-producing Escherichia coli (designed as PMPU strain) belonging to the international clone ST58, in coelomic cavity, oesophagus, lungs, small intestine and cloaca samples. PMPU strain harboured a broad resistome against antibiotics (cephalosporins, tetracyclines, aminoglycosides, sulphonamides, trimethoprim and quinolones), domestic/hospital disinfectants and heavy metals (arsenic, mercury, lead, copper and silver). Additionally, the virulence of E. coli PMPU strain was confirmed using a wax moth (Galleria mellonella) infection model, and it was supported by the presence of virulence genes encoding toxins, adherence factors, invasins and iron acquisition systems. Broad resistome and virulome of PMPU contributed to therapeutic failure and death of the animal. In brief, we report for the first time a fatal colibacillosis by MDR ESBL-producing E. coli in critically endangered Brazilian merganser, highlighting that besides colonization, critical priority pathogens are threatening wildlife. E. coli ST58 clone has been previously reported in humans, food-producing animals, wildlife and environment, supporting broad adaptation and persistence at human-animal-environment interface.

Week 96 resistance analyses of the once-daily, single-tablet regimen (STR) darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) in adults living with HIV-1 from the phase 3 randomized AMBER and EMERALD trials.

In AMBER and EMERALD, darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg demonstrated high virological response and low virological failure (VF) through week 96. Week 96 resistance analyses are presented. Post-baseline samples for genotyping/phenotyping were analyzed from protocol-defined-VFs with viral load (VL) ≥ 400 copies/ml at failure/later time points. Post-hoc analyses were deep sequencing (AMBER) and HIV-1 proviral DNA sequencing from baseline samples (VL < 50 copies/ml) (EMERALD). Through week 96 across studies, no darunavir, primary protease inhibitor (PI), or tenofovir resistance-associated-mutations (RAMs) occurred in patients continuing (N = 1125) or switching to D/C/F/TAF (N = 715). M184I/V (emtricitabine RAM) was detected in one patient in each arm of AMBER. In EMERALD D/C/F/TAF patients with prior VF and baseline genoarchive data (N = 98), 4% had darunavir RAMs, 36% emtricitabine RAMs, mainly at position 184 (32%), 4% tenofovir RAMs, and 19% ≥3 thymidine-analogue-associated-mutations at screening. The predicted phenotype showed 0% had reduced susceptibility to darunavir, 37% to emtricitabine, and 22% to tenofovir. All achieved VL < 50 copies/ml at week 96/prior discontinuation, with no VF. D/C/F/TAF has a high barrier to resistance; no darunavir, primary PI, or tenofovir RAMs occurred through 96 weeks in AMBER and EMERALD. In EMERALD, baseline archived darunavir, emtricitabine, and tenofovir RAMs in patients with prior VF did not preclude virologic response.

In Vitro Profiling of Laninamivir-Resistant Substitutions in N3 to N9 Avian Influenza Virus Neuraminidase Subtypes and Their Association with In Vivo Susceptibility.

Laninamivir (LAN) is a long-acting neuraminidase (NA) inhibitor (NAI) with a similar binding profile in the influenza NA enzyme active site as those of other NAIs, oseltamivir (OS), zanamivir (ZAN), and peramivir, and may share common resistance markers with these NAIs. We screened viruses with NA substitutions previously found during OS and ZAN selection in avian influenza viruses (AIVs) of the N3 to N9 subtypes for LAN susceptibility. Of the 72 NA substitutions, 19 conferred resistance to LAN, which ranged from 11.2- to 549.8-fold-decreased inhibitory activity over that of their parental viruses. Ten NA substitutions reduced the susceptibility to all four NAIs, whereas the remaining 26 substitutions yielded susceptibility to one or more NAIs. To determine whether the in vitro susceptibility of multi-NAI-resistant AIVs is associated with in vivo susceptibility, we infected BALB/c mice with recombinant AIVs with R292K (ma81K-N3R292K) or Q136K (ma81K-N8Q136K) NA substitutions, which impart in vitro susceptibility only to LAN or OS, respectively. Both ma81K-N3R292K and ma81K-N8Q136K virus-infected mice exhibited reduced weight loss, mortality, and lung viral titers when treated with their susceptible NAIs, confirming the in vitro susceptibility of these substitutions. Together, LAN resistance profiling of AIVs of a range of NA subtypes improves the understanding of NAI resistance mechanisms. Furthermore, the association of in vitro and in vivo NAI susceptibility indicates that our models are useful tools for monitoring NAI susceptibility of AIVs.IMPORTANCE The chemical structures of neuraminidase inhibitors (NAIs) possess similarities, but slight differences can result in variable susceptibility of avian influenza viruses (AIVs) carrying resistance-associated NA substitutions. Therefore, comprehensive susceptibility profiling of these substitutions in AIVs is critical for understanding the mechanism of antiviral resistance. In this study, we profiled resistance to the anti-influenza drug laninamivir in AIVs with substitutions known to impart resistance to other NAIs. We found 10 substitutions that conferred resistance to all four NAIs tested. On the other hand, we found that the remaining 26 NA substitutions were susceptible to at least one or more NAIs and showed for a small selection that in vitro data predicted in vivo behavior. Therefore, our findings highlight the usefulness of screening resistance markers in NA enzyme inhibition assays and animal models of AIV infections.

Hepatitis B virus mutation pattern rtA181S+T184I+M204I may contribute to multidrug resistance in clinical practice: Analysis of a large cohort of Chinese patients.

The study aimed to characterize the prevalence and virological features of the rtA181S + T184I + M204I mutant in a large cohort of patients with chronic HBV infection. In total, 22,009 nucleoside/nucleotide analog-treated patients who underwent resistance testing at the Fifth Medical Center of Chinese PLA General Hospital between 2007 and 2016 were enrolled. Serum samples were collected for HBV reverse-transcriptase gene sequencing. Phenotypic analysis of the viral replication capacity and drug susceptibility was performed. The rtA181S mutation was detected in 0.82% (180/22,009) of samples. rtA181S-positive patients had significantly higher lamivudine (LAM), adefovir (ADV), and entecavir (ETV) exposure than rtA181S-negative patients. Of 180 rtA181S-positive patients, 42 had no coexistent resistance mutations, 34 had coexisting LAM-resistance mutation (LAMr), 17 had coexisting ADV-resistance mutation (ADVr), and 86 had coexisting ETV-resistance mutation (ETVr), and one had ADVr + ETVr. rtA181S + T184I + M204I occurred in 79.1% (68/86) of patients with rtA181S + ETVr and 37.8% (68/180) of all rtA181S-positive patients. Longitudinal analysis of the clinical course of resistant mutant evolution for four representative cases showed that rtA181S + T184I + M204I developed in all patients who had received LAM/telbivudine ± ADV and was receiving ETV or ADV + ETV. Compared with wild-type, the rtA181S + T184I + M204I mutant had 53.7% lower replication capacity and >1000-, 3.9-, and 383.3-fold greater LAM, ADV, and ETV resistance, respectively, but remained sensitive to tenofovir. Artificial elimination of rtA181S from the rtA181S + T184I + M204I mutant restored viral susceptibility to ADV but decreased viral replication capacity. Our study presented the first evidence that HBV rtA181S + T184I + M204I mutation had features of multidrug-resistance that contributed to resistance to both nucleoside and nucleotide analogs.

HIV-1 drug resistance mutations detection and HIV-1 subtype G report by using next-generation sequencing platform.

BACKGROUND: Based on world health organization (WHO) recommend, drug resistance assay should be performed in initial of treatment and after treatment for administering and monitoring of anti-retroviral regime in HIV-1 infected patients. MATERIAL AND METHOD: NGS analyses were performed on forty-one plasma samples from HIV-1 affected patients using the Sentosa SQ HIV genotyping assay (Vela-Diagnostics, Germany). This system comprises a semi-automated Ion torrent based platform and the sequencing results were analyzed based on ANRS, REGA and Stanford drug resistance algorithms. Phylogenetic analysis was analyzed based on https://comet.lih.lu database as well as MEGA5 Software. RESULTS: Drug resistances were identified in thirty-three samples (80%) out of forty-one samples. The Phylogenetic analysis results showed that CRF-35AD (94%) and subtypes B (2.4%) and G (2.4%) were dominant subtypes in this study. NRTI and NNRTI associated dominant mutations were M184I/V and K103 N.High-level resistance to lamivudine (3 TC) and Emtricitabine (FTC) were detected in 34.3% of patients while 53.1% were resistant to Efavirenz (EFV) and Nevirapine (NVP). The Protease inhibitor (PI) minor and major mutations were not reported but more than 95% of samples had polymorphisms mutation in K20R, M36I, H69K, L89 M positions. These mutations are subtype dependent and completely are absent in subtype B virus. The secondary mutations were reported in positions of E157Q, S230 N, and T97A of integrase gene and four samples represent low-level resistance to integrase strand transfer inhibitor (INSTI). CONCLUSIONS: This is the first preliminary evaluation of HIV-1 drug resistance mutation (DRM) by using the Sentosa SQ HIV Genotyping Assay in Iran. The NGS represent a promising tool for the accurate detection of DRMs of CRF-35AD that is dominant subtype in Iranian HIV-1 infected population and for the first time revealed HIV-1 subtype G in Iranian population. In the present study polymorphic mutation in the position of K20R, M36I, H69K, L89 M were properly reported in CRF35AD that is dominant in Iranian HIV patients.

Susceptibility to HIV-1 integrase strand transfer inhibitors (INSTIs) in highly treatment-experienced patients who failed an INSTI-based regimen.

The aim of this study was to characterize the genotypic and phenotypic resistance profile to the integrase strand transfer inhibitor (INSTI) bictegravir (BIC) and other INSTIs in patients who previously failed twice-daily raltegravir (RAL)-based or twice-daily dolutegravir (DTG)-based regimens. Twenty-two samples were collected after failure on an INSTI-based regimen in 17 highly treatment-experienced patients with HIV-1 with multi-drug-resistant virus, recorded in the Italian PRESTIGIO registry. Genotypic resistance mutations and phenotypic susceptibility to INSTIs were detected by GeneSeqIN and PhenoSenseIN assays, respectively (Monogram Biosciences, San Francisco, CA, USA). The primary INSTI resistance substitutions E138A/K, G140S, Y143C/H/R, Q148H and N155H were detected in 14 of 22 samples and were associated with resistance to one or more INSTIs, with G140S+Q148H present in 11 of 22 samples. Of these 14 samples, all showed high levels of resistance to elvitegravir (EVG) and RAL. Two isolates contained L74M, E138K, G140S and Q148H, or L74M, T97A, S119T, E138K, G140S, Y143R and Q148H, and had high-level resistance to all INSTIs, including BIC and DTG. Intermediate resistance was reported for eight of 14 isolates for BIC and nine of 14 isolates for DTG. Overall, for the 14 INSTI-resistant isolates, the median fold-change values in phenotypic susceptibility were: BIC 3.2 [interquartile range (IQR) 0.6-66], DTG 6.3 (IQR 0.8->186), EVG >164 (IQR 2.6->164) and RAL >188 (IQR 2.7->197). In conclusion, the study findings supported the in-vitro activity of BIC and DTG against most isolates derived from highly treatment-experienced patients who failed INSTI regimens.

Genetic Diversity and Drug Resistance of HIV-1 CRF55_01B in Guangdong, China.

BACKGROUND: HIV-1 CRF55_01B was first reported in 2013. At present, no report is available regarding this new clade's polymorphisms in its functionally critical regions protease and reverse transcriptase. OBJECTIVE: To identify the diversity difference in protease and reverse transcriptase between CRF55_01B and its parental clades CRF01_AE and subtype B; and to investigate CRF55_01B's drug resistance mutations associated with the protease inhibition and reverse transcriptase inhibition. METHODS: HIV-1 RNA was extracted from plasma derived from a MSM population. The reverse transcription and nested PCR amplification were performed following our in-house PCR procedure. Genotyping and drug resistant-associated mutations and polymorphisms were identified based on polygenetic analyses and the usage of the HIV Drug Resistance Database, respectively. RESULTS: A total of 9.24 % of the identified CRF55_01B sequences bear the primary drug resistance. CRF55_01B contains polymorphisms I13I/V, G16E and E35D that differ from those in CRF01_AE. Among the 11 polymorphisms in the RT region, seven were statistically different from CRF01_AE's. Another three polymorphisms, R211K (98.3%), F214L (98.3%), and V245A/E (98.3 %.), were identified in the RT region and they all were statistically different with that of the subtype B. The V179E/D mutation, responsible for 100% potential low-level drug resistance, was found in all CRF55_01B sequences. Lastly, the phylogenetic analyses demonstrated 18 distinct clusters that account for 35% of the samples. CONCLUSION: CRF55_01B's pol has different genetic diversity comparing to its counterpart in CRF55_01B's parental clades. CRF55_01B has a high primary drug resistance presence and the V179E/D mutation may confer more vulnerability to drug resistance.

Multidrug-resistant HIV viral rebound during early syphilis: a case report.

BACKGROUND: Syphilis has been associated with an increase in HIV RNA and a temporary decline in CD4 T cell counts in people living with HIV who are not receiving antiretroviral treatment (ART), and may be associated with a transient HIV RNA rebound in those who are receiving ART. Our case is the first to highlight the risk of a multidrug-resistant HIV viral rebound during the course of early syphilis even if antiretroviral drug concentrations are within the therapeutic range. CASE PRESENTATION: This 50-year-old HIV-1-positive male patient with concomitant early syphilis presented with an HIV RNA rebound (8908 copies/mL) during a scheduled visit to our clinic. He was receiving a stable ART regimen consisting of darunavir/cobicistat plus dolutegravir, and had a 15-year history of viral suppression. Good short-term drug adherence could be inferred as liquid chromatography tandem mass spectrometry showed that his trough antiretroviral drug concentrations were within the therapeutic range: darunavir 2353 ng/mL (minimum effective concentration > 500 ng/mL) and dolutegravir 986 ng/mL (minimum effective concentration > 100 ng/mL). A plasma RNA genotype resistance test revealed wild-type virus in the integrase region and protease region (PR), but extensive resistance in the reverse transcriptase (RT) region (M41L, E44D, D67N, K70R, M184V, L210W and T215Y). Phylogenetic analysis of next-generation sequences (used to investigate the presence of minor viral variants), the PR and RT sequences from plasma HIV RNA and pro-viral DNA extracted from peripheral blood mononuclear cells during the viral rebound, and a Sanger sequence obtained during a previous virological failure suggested clonal viral expression because the previous PR resistance mutations had been lost or had not been archived in pro-viral DNA. CONCLUSIONS: This case shows that early syphilis may cause an HIV RNA rebound in patients under stable virological control with the potential of transmitting an extensively drug-resistant virus.

HIV-1 subtype C predicted co-receptor tropism in Africa: an individual sequence level meta-analysis.

BACKGROUND: Entry inhibitors, such as Maraviroc, hold promise as components of HIV treatment and/or pre-exposure prophylaxis in Africa. Maraviroc inhibits the interaction between HIV Envelope gp120 V3-loop and CCR5 coreceptor. HIV-1 subtype C (HIV-1-C) is predominant in Southern Africa and preferably uses CCR5 co-receptor. Therefore, a significant proportion of HIV-1-C CXCR4 utilizing viruses (X4) may compromise the effectiveness of Maraviroc. This analysis examined coreceptor preferences in early and chronic HIV-1-C infections across Africa. METHODS: African HIV-1-C Envelope gp120 V3-loop sequences sampled from 1988 to 2014 were retrieved from Los Alamos HIV Sequence Database. Sequences from early infections (< 186 days post infection) and chronic infections (> 186 days post infection) were analysed for predicted co-receptor preferences using Geno2Pheno [Coreceptor] 10% FPR, Phenoseq-C, and PSSMsinsi web tools. V3-loop diversity was determined, and viral subtype was confirmed by phylogenetic analysis. National treatment guidelines across Africa were reviewed for Maraviroc recommendation. RESULTS: Sequences from early (n = 6316) and chronic (n = 7338) HIV-1-C infected individuals from 10 and 15 African countries respectively were available for analyses. Overall, 518/6316 (8.2%; 95% CI 0.7-9.3) of early sequences were X4, with Ethiopia and Malawi having more than 10% each. For chronic infections, 8.3% (95% CI 2.4-16.2) sequences were X4 viruses, with Ethiopia, Tanzania, and Zimbabwe having more than 10% each. For sequences from early chronic infections (< 1 year post infection), the prevalence of X4 viruses was 8.5% (95% CI 2.6-11.2). In late chronic infections (≥ 5 years post infection), X4 viruses were observed in 36% (95% CI - 16.3 to 49.9), with two countries having relatively high X4 viruses: South Africa (43%) and Malawi (24%). The V3-loop amino acid sequence were more variable in X4 viruses in chronic infections compared to acute infections, with South Africa, Ethiopia and Zimbabwe showing the highest levels of V3-loop diversity. All sequences were phylogenetically confirmed as HIV-1-C and clustered according to their co-receptor tropism. In Africa, Maraviroc is registered only in South Africa and Uganda. CONCLUSIONS: Our analyses illustrate that X4 viruses are present in significantly similar proportions in early and early chronic HIV-1 subtype C infected individuals across Africa. In contrast, in late chronic infections, X4 viruses increase 3-5 folds. We can draw two inferences from our observations: (1) to enhance the utility of Maraviroc in chronic HIV subtype C infections in Africa, prior virus co-receptor determination is needed; (2) on the flip side, research on the efficacy of CXCR4 antagonists for HIV-1-C infections is encouraged. Currently, the use of Maraviroc is very limited in Africa.

Comparison of HIV drug resistance profiles across HIV-1 subtypes A and D for patients receiving a tenofovir-based and zidovudine-based first line regimens in Uganda.

BACKGROUND: Resistance to antiretroviral drugs is a major challenge among Human Immunodeficiency Virus (HIV) positive patients receiving antiretroviral therapy (ART). Mutations that arise as a result of this are diverse across the various drugs, drug classes, drug regimens and subtypes. In Uganda, there is a paucity of information on how these mutations differ among the different drug regimens and the predominant HIV-1 subtypes. The purpose of this study was to determine mutation profile differences between first-line drug regimens: TDF/3TC/EFV and AZT/3TC/EFV and HIV-1 subtypes: A and D in Uganda. The study also investigated the potential usage of rilpivirine, doravirine and etravirine in patients who failed treatment on efavirenz. METHODS: A retrospective study was conducted on 182 archived plasma samples obtained from patients who were experiencing virological failure between 2006 and 2017 at five Joint Clinical Research Center (JCRC) sites in Uganda. Sanger sequencing of the Reverse Transcriptase (RT) gene from codons 1-300 was done. Mutation scores were generated using the Stanford University HIV Drug Resistance Database. A Chi-square test was used to determine the association between drug resistance mutations (DRMs) and drug regimens or HIV-1 subtypes. RESULTS: The prevalence of DRMs was 84.6% among patients failing a first-line efavirenz (EFV)-based regimen. The most prevalent Nucleoside Reverse Transcriptase Inhibitor (NRTI) mutations were M184V/I (67.3%), K219/Q/E (22.6%) and K65R (21.1%). While K103N (50.8%) and G190A/S/E/G (29.1%) were the most prevalent Non-Nucleoside Reverse Transcriptase Inhibitor (NNTRI) mutations. As expected, discriminatory DRMs such as K65R, L74I, and Y115F were noted in Tenofovir (TDF) containing regimens while the Thymidine Analogue Mutations (TAMs) L210W and T215 mutations were in Zidovudine (AZT)-based regimens. No significant difference (p = 0.336) was found for overall DRMs between HIV-1 subtypes A and D. Among the patients who had resistance to EFV, 37 (23.6%) were susceptible to newer NNRTIs such as Rilpivirine and Etravirine. CONCLUSION: Accumulation of DRMs between AZT/3TC/EFV and TDF/3TC/EFV is comparable but individual mutations that confer resistance to particular drugs should be considered at virological failure. Having either HIV-1 subtype A or D is not associated with the acquisition of DRMs, therefore HIV diversity should not determine the choice of treatment. Rilpivirine, etravirine and doravirine had minimal benefits for patients who failed on efavirenz.

Perspectives on the Barrier to Resistance for Dolutegravir + Lamivudine, a Two-Drug Antiretroviral Therapy for HIV-1 Infection.

In HIV-1-infected patients, virological failure can occur as a consequence of the mutations that accumulate in the viral genome that allow replication to continue in the presence of antiretrovirals (ARVs). The development of treatment-emergent resistance to an ARV can limit a patient's options for future therapy, prompting the need for ARV regimens that are resilient to the emergence of resistance. The genetic barrier to resistance refers to the number of mutations in an ARV's therapeutic target that are required to confer a clinically meaningful loss of susceptibility to the drug. The emergence of resistance can be affected by pharmacological aspects of the ARV, including its structure, inhibitory quotient, therapeutic index, and pharmacokinetic characteristics. Dolutegravir (DTG) has demonstrated a high barrier to resistance, including when used in a two-drug regimen (2DR) with lamivudine (3TC). In the GEMINI-1 and GEMINI-2 studies, DTG +3TC was noninferior to DTG + emtricitabine/tenofovir disoproxil fumarate in treatment-naive participants, with similar proportions achieving HIV-1 RNA <50 copies/mL through 96 weeks. Furthermore, in the TANGO study, virological suppression was maintained at 48 weeks after switching to DTG +3TC from a tenofovir alafenamide (TAF)-based regimen compared with continuing a TAF-based regimen. Most other 2DRs with successful outcomes compared with three-drug regimens have been based on protease inhibitors (PIs); however, this class is associated with adverse metabolic effects and drug-drug interactions. In this review, we discuss the barrier to resistance in the context of a 2DR in which a boosted PI is replaced with DTG +3TC.