Reverse Transcriptase Inhibitor Mutations Research Articles

Temporal trends and transmission dynamics of pre-treatment HIV-1 drug resistance within and between risk groups in Kenya, 1986-2020.

Evidence on the distribution of pre-treatment HIV-1 drug resistance (HIVDR) among risk groups is limited in Africa. We assessed the prevalence, trends and transmission dynamics of pre-treatment HIVDR within and between MSM, people who inject drugs (PWID), female sex workers (FSWs), heterosexuals (HETs) and perinatally infected children in Kenya. HIV-1 partial pol sequences from antiretroviral-naive individuals collected from multiple sources between 1986 and 2020 were used. Pre-treatment reverse transcriptase inhibitor (RTI), PI and integrase inhibitor (INSTI) mutations were assessed using the Stanford HIVDR database. Phylogenetic methods were used to determine and date transmission clusters. Of 3567 sequences analysed, 550 (15.4%, 95% CI: 14.2-16.6) had at least one pre-treatment HIVDR mutation, which was most prevalent amongst children (41.3%), followed by PWID (31.0%), MSM (19.9%), FSWs (15.1%) and HETs (13.9%). Overall, pre-treatment HIVDR increased consistently, from 6.9% (before 2005) to 24.2% (2016-20). Among HETs, pre-treatment HIVDR increased from 6.6% (before 2005) to 20.2% (2011-15), but dropped to 6.5% (2016-20). Additionally, 32 clusters with shared pre-treatment HIVDR mutations were identified. The majority of clusters had R0 ≥ 1.0, indicating ongoing transmissions. The largest was a K103N cluster involving 16 MSM sequences sampled between 2010 and 2017, with an estimated time to the most recent common ancestor (tMRCA) of 2005 [95% higher posterior density (HPD), 2000-08], indicating propagation over 12 years. Compared to HETs, children and key populations had higher levels of pre-treatment HIVDR. Introduction of INSTIs after 2017 may have abrogated the increase in pre-treatment RTI mutations, albeit in the HET population only. Taken together, our findings underscore the need for targeted efforts towards equitable access to ART for children and key populations in Kenya.

Persistence of Human Immunodeficiency Virus-1 Drug Resistance Mutations in Proviral Deoxyribonucleic Acid After Virologic Failure of Efavirenz-Containing Antiretroviral Regimens.

BackgroundEfavirenz (EFV)-based regimens select broad drug resistance to nonnucleoside reverse-transcriptase inhibitors (NNRTIs), limiting the effectiveness of EFV and other NNRTIs. The duration, persistence, and decay of drug resistance mutations (DRMs) in the proviral reservoir is not well defined.MethodsParticipants with virologic failure of EFV-based regimens and drug-resistant viremia with the K103N mutation in plasma ribonucleic acid (RNA) were identified from AIDS Clinical Trials Group (ACTG) studies A364 and A5095. These individuals received a second-line, boosted protease inhibitor-based regimen with suppression of viremia for up to10 years during long-term follow-up (median = 3.6 years; interquartile range, 2.1–6.9 years). Proviral deoxyribonucleic acid (DNA) from cryopreserved peripheral blood mononuclear cells was sequenced to identify the persistence of DRM.ResultsTwenty-eight participants from ACTG 364 and ACTG 5095 were evaluated. Sanger sequencing of proviral DNA detected K103N as well as additional reverse-transcriptase inhibitor (RTI) mutations. Ultradeep sequencing confirmed persistence of K103N in 71% of participants with minimal decay over time. In an adjusted model including years since suppression, persistent proviral K103N was 2.6 times more likely (95% confidence interval, 1.0–6.4) per log10 higher human immunodeficiency virus RNA at EFV failure.ConclusionsPersistence of RTI mutations in proviral DNA after virologic failure has implications for the effectiveness of future drug regimens and the recycling of RTI drugs.

Predictors of HIV virological failure and drug resistance in Chinese patients after 48 months of antiretroviral treatment, 2008–2012: a prospective cohort study

ObjectiveTo explore factors associated with HIV virological failure (VF) and HIV drug resistance (HIVDR) among HIV-positive Chinese individuals 4 years after initiating first-line lamivudine-based antiretroviral treatment (ART) in 2008 at...

Commonly Transmitted HIV-1 Drug Resistance Mutations in Reverse-Transcriptase and Protease in Antiretroviral Treatment-Naive Patients and Response to Regimens Containing Tenofovir Disoproxil Fumarate or Tenofovir Alafenamide.

The presence of transmitted drug resistance mutations (TDRMs) in antiretroviral treatment (ART)-naive patients can adversely affect the outcome of ART. Resistance testing was conducted in 6704 ART-naive subjects predominantly from the United States and Europe in 9 clinical studies conducted by Gilead Sciences from 2000 to 2013. The presence of TDRMs increased during this period (from 5.2% to 11.4%), primarily driven by an increase in nonnucleoside reverse-transcriptase (RT) inhibitor (NNRTI) resistance mutations (from 0.3% to 7.1%), particularly K103N/S (increase from 0.3% to 5.3%). Nucleoside/nucleotide RT inhibitor mutations were found in 3.1% of patients. Only 1 patient had K65R (0.01%) and 7 had M184V/I (0.1%), despite high use of tenofovir disoproxil fumarate (TDF), emtricitabine, and lamivudine and potential transmission of resistance to these drugs. At least 1 thymidine-analogue mutations was present in 2.7% of patients with 0.07% harboring T215Y/F and 2.7% harboring T215 revertant mutations (T215rev). Patients with the combination of M41L + L210W + T215rev showed full human immunodeficiency virus RNA suppression while receiving a TDF- or tenofovir alafenamide-containing regimen. There was an overall increase of TDRMs among patients enrolling in clinical trials from 2000 through 2013, driven primarily by an increase in NNRTI resistance. However, the presence of common TDRMs, including thymidine-analogue mutations/T215rev, showed no impact on response to TDF- or tenofovir alafenamide-containing regimens.

Effect on HIV-1 viral replication capacity of DTG-resistance mutations in NRTI/NNRTI resistant viruses.

BackgroundRecommended regimens for HIV-positive individuals include the co-administration of dolutegravir (DTG) with two reverse transcriptase inhibitors (RTIs). Although rare, emerging resistance against DTG is often associated with the R263K substitution in integrase. In-vitro-selected R263K was associated with impaired viral replication capacity, DNA integration, and integrase strand-transfer activity, especially when accompanied by the secondary mutation H51Y. Given the reduced fitness of RTI-resistant viruses, we investigated potential impacts on viral replication of combining R263K and H51Y/R263K with major RTI-resistance substitutions including K65R, L74V, K103N, E138K, and M184I/V.ResultsWe combined the R263K or H51Y/R263K with RTI-resistance mutations into the proviral plasmid pNL4.3 and measured the resulting viral infectiousness, replication capacity, and ability to integrate viral DNA into host cells. Infectiousness was determined by luciferase assay in TZM-bl cells. Replicative capacity was monitored over 7 days and viral DNA integration was studied by real-time Alu-qPCR in PM1 cells. We found that viral infectiousness, replication capacities and integration levels were greatly reduced in triple mutants, i.e. H51Y/R263K plus a RT mutation, and moderately reduced in double mutants, i.e. R263K plus a RT mutation, compared to wild-type and single RT-mutant viruses.ConclusionsOur findings help to explain the absence of RTI mutations in individuals who experienced DTG-treatment failure.

Characterization of drug resistance mutations in ART-naïve HIV-1 infected children in Northern Vietnam

ObjectiveTo investigate the profile of drug resistance-associated mutations in pol gene of antiretroviral therapy-naïve HIV-1 infected children enrolled in National Hospital Pediatrics in Northern Vietnam. MethodsGenotyping was performed on 134 antiretroviral therapy-naïve plasma samples from HIV-1 infected children. HIV-1 pol gene was amplified using primers for protease and reverse transcriptase and sequenced using the BigDye chemistry. The mutations were analyzed based on the Stanford University HIV-1 Drug Resistance Database and ISA-USA list. ResultsAll the children were infected with HIV-1 CRF01_AE subtype. Major protease inhibitor resistance mutations were found in 2 children (2.3%) and reverse-transcriptase inhibitor resistance mutations were found in 5 children (7.7%). The protease inhibitor mutations were observed M46L and L90M and reverse-transcriptase inhibitor mutations were M184I, K65R, Q151M, T69N, L210W, Y181C, M230L and K101E. ConclusionsThis is the first study reporting the prevalence of drug resistance-associated mutation in naïve HIV-1 infected children in Northern Vietnam. These data also emphasize the importance of genotypic resistance testing of HIV-1 infected children before initiating treatment in order to achieve better clinical outcome.

Prevalence of Transmitted HIV-1 Drug Resistance among Young Adults Attending HIV Counselling and Testing Clinics in Kigali, Rwanda

Scaling-up antiretroviral therapy (ART) in resource-limited settings has raised concerns of emerging HIV drug resistance (DR) and its transmission to newly infected individuals. To assess the prevalence of transmitted drug resistance (TDR) in recently HIV-infected individuals, a WHO TDR threshold survey was conducted among young adults in Kigali, Rwanda. Between May and July 2011, HIV subtype and genotyping were performed on dried blood spots (DBS) prepared from blood specimens collected from newly HIV-diagnosed and ART-naive individuals aged 15 to 21 years in eight HIV voluntary counselling and testing (VCT) sites in Kigali. In total, 57 of the 68 DBS collected from eligible participants were successfully amplified. The median age of participants was 20 years and 86% were female. Most participants (96%) were infected with subtype A1 virus. Two participants (4%) had the K103N non-nucleoside reverse transcriptase inhibitor (NNRTI) mutation and one (2%) had the M46L protease inhibitor (PI) mutation. The TDR prevalence was 3.5% (95% CI 0.4, 12.1) for NNRTI and 1.8% (95% CI 0.0, 9.4) for PI. The prevalence of HIV TDR in VCT attendees in Kigali was characterized as low (<5%) for all drug classes according to the WHO HIV DR threshold survey methodology. Despite a decade of widespread ART in Rwanda, TDR prevalence remains low, and so the current first-line ART regimens should continue to be effective. However, as scale-up of ART continues, frequent HIV DR surveillance is needed to monitor the effectiveness of available ART regimens at the population level.

Short communication: east meets west: a description of HIV-1 drug resistance mutation patterns of patients failing first line therapy in PEPFAR clinics from Uganda and Nigeria.

HIV-1 viral load (VL) monitoring is recommended but seldom performed in resource-constrained countries. An evaluation of patients receiving first-line antiretroviral therapy in a multicountry PEPFAR program (RV288) was performed to determine the rates and predictors of virologic suppression. Resistance data from treatment failures are available from Uganda and Nigeria. Each country enrolled 325 subjects into this cross-sectional study. Subjects on first-line therapy were randomly selected for HIV RNA testing (viral load). Regimens included efavirenz or nevirapine with zidovudine/lamivudine or tenofovir/lamivudine. VL was determined from plasma using the Roche COBAS TaqMan HIV-1 Test, High Pure System v1.0 (47 copies/ml). Genotypic resistance testing was performed on samples with VL>1,000 copies/ml. From Uganda, 85% of subjects were undetectable while 7% (23/325) had VL>1,000 copies/ml. The HIV-1 subtype distribution was as follows: A=47.6%, C=14.3%, and D=38.1%. No resistance mutations were found in 14% of subjects. All subjects with resistance had the M184V mutation. Of subjects failing a zidovudine regimen less than 1 year, 88% (7/8) had no thymidine analogue mutations (TAMs), compared to 50% (4/8) failing greater than 1 year. Four subjects (25%) had more than two mutations from the TAM-1 pathway (41L, 210W, 215Y). In Nigeria, 82% were undetectable while 14% (45/325) had VL>1,000 copies/ml. HIV-1 subtype distribution was as follows: 62.8%=CRF02_AG, 34%=pure G, and 2.8%=A. Of the 35 genotyped subjects, 14% (5/35) had no resistance mutations. Of the remainder, 10% (3/30) had no nucleoside analogue mutations while 33% (10/30) had only M184V along with nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations. Forty percent (10/25) of subjects on zidovudine failed without TAMs. Another 25% (5/25) of subjects failing on zidovudine had more than two TAM-1 mutations. Individuals failing first-line antiretroviral therapy (ART) may retain sensitivity to one or more nucleoside analogues from the regimen. Knowledge of drug resistance patterns allow for selection of drugs that can be recycled in future regimens. Accumulation of resistance mutations may compromise future treatment options.

Switching to an Etravirine-Containing Regimen Due to Drug Intolerance in Clinical Practice

Background: Drug intolerance is one of the main reasons for switching antiret-roviral therapy in HIV-infected patients. Etravirine (ETR) has demonstrated good tolerability in clinical trials and may be an option for patients who switch therapy due to adverse events. Methods: We retrospectively reviewed all patients who had switched to an ETR-containing regimen in our center due to side effects. Virological suppression, ETR discontinuation, and reasons for discontinuation were studied. Results: A total of 78 patients started treatment with ETR in our center due to previous regimen toxicity. Most of them were men (83.3%), and the median time of infection was 14 years (IQR, 6.5–20 years). HIV RNA was <35 copies/mL in 88.3% of patients, although 33% had archived non-nucleos(t)ide reverse transcriptase inhibitor (NNRTI) mutations that did not compromise ETR efficacy. Efavirenz was the drug most often replaced (38.5%), followed by atazanavir (20.5%) and lopinavir (6.4%). The fixed combination of Trizivir was changed in another 10.3% of patients. After a median follow-up of 14 months (IQR, 6–23), the rate of virologic suppression was 79.5% and 98.4% in intention-to-treat and on-treatment analysis, respectively. Seven patients discontinued treatment due to adverse events (3 gastrointestinal disturbances, 2 rashes, 1 swelling, and 1 neuropathy). ETR was combined with 2 nucleos(t)ide analogues in 75.4% of patients. Conclusion: In HIV patients who report drug side effects, switching to an ETR-containing regimen is a safe strategy in terms of virological suppression and toxicity.

Transmitted human immunodeficiency virus-1 drug resistance in a cohort of men who have sex with men in Belo Horizonte, Brazil - 1996-2012

The presence of transmitted human immunodeficiency virus (HIV)-1 drug-resistance (TDR) at the time of antiretroviral therapy initiation is associated with failure to achieve viral load (VL) suppression. Here, we report TDR surveillance in a specific population of men who have sex with men (MSM) in Belo Horizonte, Brazil. In this study, the rate of TDR was evaluated in 64 HIV-infected individuals from a cohort of MSM between 1996-June 2012. Fifty-four percent had a documented recent HIV infection, with a seroconversion time of less than 12 months. The median CD4+T lymphocyte count and VL were 531 cells/mm3 and 17,746 copies/mL, respectively. Considering the surveillance drug resistance mutation criteria, nine (14.1%) patients presented TDR, of which three (4.7%), five (7.8%) and four (6.2%) had protease inhibitors, resistant against nucleos(t)ide transcriptase inhibitors and against non-nucleoside reverse-transcriptase inhibitors mutations, respectively. Two of the patients had multi-drug-resistant HIV-1. The most prevalent viral subtype was B (44, 68.8%), followed by subtype F (11, 17.2%). This study shows that TDR may vary according to the population studied and it may be higher in clusters of MSM.

Transmitted human immunodeficiency virus-1 drug resistance in a cohort of men who have sex with men in Belo Horizonte, Brazil - 1996-2012

The presence of transmitted human immunodeficiency virus (HIV)-1 drug-resistance (TDR) at the time of antiretroviral therapy initiation is associated with failure to achieve viral load (VL) suppression. Here, we report TDR surveillance in a specific population of men who have sex with men (MSM) in Belo Horizonte, Brazil. In this study, the rate of TDR was evaluated in 64 HIV-infected individuals from a cohort of MSM between 1996-June 2012. Fifty-four percent had a documented recent HIV infection, with a seroconversion time of less than 12 months. The median CD4+T lymphocyte count and VL were 531 cells/mm3and 17,746 copies/mL, respectively. Considering the surveillance drug resistance mutation criteria, nine (14.1%) patients presented TDR, of which three (4.7%), five (7.8%) and four (6.2%) had protease inhibitors, resistant against nucleos(t)ide transcriptase inhibitors and against non-nucleoside reverse-transcriptase inhibitors mutations, respectively. Two of the patients had multi-drug-resistant HIV-1. The most prevalent viral subtype was B (44, 68.8%), followed by subtype F (11, 17.2%). This study shows that TDR may vary according to the population studied and it may be higher in clusters of MSM.

Diversity of HIV Type 1 and Drug Resistance Mutations Among Injecting Drug Users in Kenya

Drug use in Kenya dates back to the precolonial period but research among drug users in relation to human immunodeficiency virus (HIV)-associated risk and intervention strategies has been low. To evaluate HIV-1 diversity and drug resistance among injecting drug users (IDUs), a cross-sectional study involving 58 patients was carried out in Mombasa between February and March 2010. HIV-1 RNA was extracted from plasma and polymerase chain reaction using specific primers for HIV-1 reverse transcriptase was done. Population sequencing was done and subtypes were determined phylogenetically. The prevalent HIV-1 subtypes were A1 (52/58), D (5/58), and C (2/58). The prevalence of drug resistance was 13.8% (8/58) with detection of nucleoside reverse transcriptase inhibitor (NRTI) mutations, T215F (n=5), K219Q (n=3), M184V (n=1), and nonnucleoside RTI mutation, K103N (n=1). Antiretroviral therapy (ART) and its monitoring among infected Kenyan IDUs is feasible. Policymakers and service providers in HIV prevention initiatives should improve service delivery so as to measure ART coverage among IDUs to prevent further transmission of drug-resistant variants.

Prevalence of Antiretroviral Drug Resistance Mutations and HIV-1 Subtypes among Newly-diagnosed Drugnaïve Persons Visiting A Voluntary Testing and Counselling Centre in Northeastern South Africa

Data on antiretroviral drug resistance among drug-naive persons are important in developing sentinel and surveillance policies. This study was conducted to determine the prevalence of antiretroviral drug resistance mutations among drug-naïve HIV-infected individuals attending a voluntary testing and counselling centre at the Mankweng Hospital in northeastern South Africa. In total, 79 drug-naïve HIV-positive individuals were sequentially recruited during February 2008-December 2008. Drug resistance mutations were determined using the calibrated population resistance tool available on the Stanford HIV drug resistance database. Viral DNA was obtained from 57 (72%) of the 79 individuals. Reliable nucleotide sequences were obtained for 54 reverse transcriptase (RT) and 54 protease (PR) gene regions from 54 individuals. Overall, five sequences (9.3%) harboured drug resistance mutations (95% confidence interval -1.53 to 16.99). Four (7.4%) of these were nucleoside RT inhibitor mutations (D67G, D67E, T69D, and T215Y), and one (1.9%) was a PR inhibitor mutation (M46I). No major non-nucleoside RT resistance mutation was detected. Several minor resistance mutations and polymorphisms common in subtype C viruses were observed in the PR and RT genes. Phlyogenetic analysis of the partial pol sequences showed that 52 (96%) of the 54 isolates were HIV-1 subtype C. One isolate (08MB08ZA) was HIV-1 subtype B while another (08MB26ZA) was related to HIV-1 subtype J. HIV-1 subtype recombination analysis with REGA assigned the pol sequence to HIV subtype J (11_cpx) with a bootstrap value of 75%. The prevalence of drug resistance mutations observed in the population studied was relatively higher than previously reported from other parts of South Africa. In addition, this is apparently the first report of an HIV-1 subtype J-like virus from northeastern South Africa.

Surveillance of Transmitted HIV Type 1 Drug Resistance Among HIV Type 1-Positive Women Attending an Antenatal Clinic in Kakinada, India

The World Health Organizations HIV Drug Resistance (WHO HIVDR) Threshold survey method was used to assess transmitted HIVDR in newly diagnosed HIV-1-infected primigravida women attending the Prevention of Parent to Child Transmission (PPTCT) centers in Kakinada, in whom it is likely that the infection had recently occurred. Out of the 56 consecutively collected eligible specimens, 51 were tested using the ViroSeq RT-PCR method (Abbott Germany) to obtain 47 consecutive sequences for the HIV-1 protease (PR) and reverse transcriptase (RT) region. As per the 2009 WHO list of mutations for surveillance of transmitted HIVDR, only one nonnucleoside reverse transcriptase inhibitor (NNRTI) mutation was detected at K101E from all specimens tested, suggesting a low prevalence (<5%) of resistance to NNRTIs and no mutations were detected at other sites, suggesting a low prevalence (<5%) of resistance to nucleoside reverse transcriptase inhibitors (NRTI) and protease inhibitors (PI) drug classes as well. Phylogenetic analysis showed all sequences belonged to HIV-1 subtype C. In the wake of antiretroviral treatment (ART) scale-up, future evaluation of transmitted HIVDR is essential in Kakinada as well as in other regions of India.

Moderate Prevalence of Transmitted Drug Resistance and Interiorization of HIV Type 1 Subtype C in the Inland North State of Tocantins, Brazil

The diverse Brazilian AIDS epidemic has reached small cities and scant molecular information is available about the epidemic in Northern Brazil, where the incidence is growing. This study describes transmitted drug resistance and subtypes in the protease (PR) and reverse transcriptase (RT) regions among naive patients recruited in Palmas, the capital of Tocantins State, a newly built city in Northern Brazil. PR/RT regions were retrotranscribed from plasma HIV-1 RNA and 52 were sequenced after direct nested PCR. HIV-1 subtypes were assigned by phylogenetic analysis. Transmitted drug resistance was analyzed by the Calibrated Population Resistance tool Stanford Surveillance Drug Resistance Mutation. Most patients included (59.6%) were males, the median age was 30 years and were mainly referred because of heterosexual or homosexual unprotected sex. One male patient was from the Karajás indigenous tribe. The prevalence of transmitted resistance was 11.5% (CI 95%, 4.4-23.4%): nonnucleoside RT inhibitor mutations (n=3), nucleoside RT inhibitor mutations (n=2), and protease inhibitor mutations (n=1). Dual or triple class resistance was not observed. HIV-1 subtype B(PR)/B(RT) represented 78.8%, 5.8% were subtype C(PR)/C(RT), and 1.9% were subtype F1(PR)/F1(RT). Recombinant viruses represented 13.5% (07/52): B(PR)/F1(RT) (n=1), B(PR)/BF1(RT) (n=4), and C(PR)/CF1(RT) (n=2). This study about the AIDS epidemic in the recently founded city of Palmas/Tocantins in inland Northern Brazil shows moderate levels of transmitted drug resistance and the circulation of diverse recombinant viruses. This pattern is similar to what has been described in major metropolitan cities, suggesting the influence of imported cases from the south/southeast. Moreover these results indicate that patients from this setting should be monitored regarding transmitted drug resistance mutations.

Genetic Characterization of HIV Type 1 Among Patients with Suspected Immune Reconstitution Inflammatory Syndrome After Initiation of Antiretroviral Therapy in Kenya

Antiretroviral therapy (ART) has improved the survival of HIV patients but is also associated with unique manifestations of disease in some subjects during the initial months of therapy. Immune reconstitution inflammatory syndrome (IRIS) is a disorder among individuals starting ART, with no evidence-based treatment and management guidelines. We characterized HIV-1 and determined drug resistance among 14 Kenyan patients with suspected IRIS after ART initiation in 2005. Polymerase chain reaction, sequencing, and phylogenetic analysis of viral pol and env showed the following HIV-1 subtypes: A1/A1/A1 (pol-RT/gp41/C2V3), 5; A1/C/A1, 1; A1/D/A1, 2; D/A1/A1, 1; D/C/A1, 1; D/D/A1, 2; D/D/D, 1; and D/A1/A2, 1. Three patients had viruses with major drug resistance-associated mutations. These included nucleoside reverse transcriptase inhibitor (RTI) mutations: M41L, K65R, D67N, K70R, M184V, and K219Q, and nonnucleoside RTI mutations: K101P, L100I, K103N, and Y181C. Twelve patients harbored viruses that are predicted to use chemokine coreceptor 5 (CCR5) whereas two had variant viruses predicted to use the CXCR4 coreceptor. Drug resistance may not be the only cause of ART adverse events. HIV-1 characterization would be important before and during HIV therapy to avoid treatment failure.

496 LECTIN COMPLEMENT PATHWAY GENES OF DONOR AND RECIPIENT DETERMINE THE RISK OF CLINICALLY SIGNIFICANT INFECTIONS AFTER ORTHOTOPIC LIVER TRANSPLANTATION

for protease inhibitors (PI) (I13V, L33V, M36I, K43T, L63P, I64V, A71T, V77I). None harboured non-nucleoside reverse transcriptase inhibitors (NNRTI) mutations resistance. Virological failure under raltegravir (RAL) and enfuvirtide (ENF) was linked to the selection of the Q148R mutation and the N43D mutation. Three isolates had complete or possible resistance to NRTI (Stanford algorithm). Therapeutic trough levels of IS were maintained within the therapeutic target ranges. ARV adherence was suboptimal for one patient under ENF. HIV viral load became undetectable for all patients after changing ARV.

Discordance Between Cerebral Spinal Fluid and Plasma HIV Replication in Patients with Neurological Symptoms Who Are Receiving Suppressive Antiretroviral Therapy

We report data on 11 patients with neurological symptoms and human immunodeficiency virus (HIV) cerebrospinal fluid (CSF) viremia contrasting with suppressed plasma HIV RNA during receipt of combined antiretroviral therapy. We retrospectively identified instances of central nervous system (CNS) symptoms in patients who had been receiving stable combination antiretroviral therapy. Discordance between plasma and CSF HIV RNA levels was defined by any detectable CSF HIV RNA level >200 copies/mL while plasma levels were <50 copies/mL or by a CSF HIV RNA level that was 1 log greater than the plasma HIV RNA level. Eleven patients had experienced acute or subacute neurological symptoms. All but one patient had CSF pleocytosis and/or elevated protein levels. The median CSF HIV RNA level was 880 copies/mL (range, 558-12,885 copies/mL). Patients had been receiving stable combination antiretroviral therapy for a median of 13 months (range, 10-32 months). Eight of 11 patients had a plasma HIV RNA level <50 copies/mL, and 3 had plasma HIV RNA blips with their CSF HIV RNA level >1 log higher than their plasma HIV RNA level. Resistance-associated mutations were detected in 7 of 8 CSF HIV RNA genotypic strains. The median number of resistance-associated mutations was 6 (range, 2-8) to nucleoside reverse-transcriptase inhibitors and 3 (range, 1-9) to protease inhibitors. One patient had a virus harboring nonnucleoside reverse-transcriptase inhibitor mutations. The median central nervous system penetration-effectiveness (CPE) rank was 2 (range, 1-3), and 5 patients had a CPE 1.5. After antiretroviral therapy optimization based on genotypes and CPE, all patients clinically improved, with normalization of CSF. Despite successful suppression of plasma viremia with antiretroviral therapy, HIV may replicate in CSF, with development of CSF HIV resistance resulting in acute or subacute neurological manifestations.

Transmission of HIV‐1 Drug‐Resistant Variants: Prevalence and Effect on Treatment Outcome

Human immunodeficiency virus type 1 (HIV-1) drug resistance is an important threat to the overall success of antiretroviral therapy (ART). Because of the limited sensitivity of commercial assays, transmitted drug resistance (TDR) may be underestimated; thus, the effect that TDR has on treatment outcome needs to be investigated. The objective of this study was to investigate the prevalence of TDR in HIV-infected patients and to evaluate the significance of TDR with respect to treatment outcome by analyzing plasma viral RNA and peripheral blood mononuclear cell proviral DNA for the presence of drug resistance mutations. In a prospective study, we investigated the level of TDR in 61 patients by comparing the results of a sensitive multiplex-primer-extension approach (termed HIV-SNaPshot) that is capable of screening for 9 common nucleoside reverse-transcriptase inhibitor and nonnucleotide reverse-transcriptase inhibitor mutations with those of a commercial genotyping kit, ViroSeq (Abbott). Twenty-two patients were found to carry mutations. More patients with TDR were identified by the HIV-SNaPshot assay than by ViroSeq analysis (33% vs 13%; [P=.015). There was no significant difference in the time from initiation of ART to virological suppression between susceptible patients and those carrying low- or high-level resistance mutations (mean +/- standard deviation, 128 +/- 59.1 vs 164.9 +/- 120.4; P=.147). Furthermore, analyses of CD4 cell counts showed no significant difference between these 2 groups 1 year after the initiation of ART (mean, 184 vs 219 cells/microL; P=.267). We found the prevalence of TDR in recently infected ART-naive patients to be higher than that estimated by ViroSeq genotyping alone. Follow-up of patients after treatment initiation showed a trend toward there being more clinical complications for patients carrying TDR, although a significant effect on treatment outcome could not be demonstrated. Therefore, the clinical relevance of low-abundance resistant quasispecies in early infection is still in question.

Viral Rebound and Emergence of Drug Resistance in the Absence of Viral Load Testing: A Randomized Comparison between Zidovudine‐Lamivudine plus Nevirapine and Zidovudine‐Lamivudine plus Abacavir

We investigated virological response and the emergence of resistance in the Nevirapine or Abacavir (NORA) substudy of the Development of Antiretroviral Treatment in Africa (DART) trial. Six hundred symptomatic antiretroviral-naive human immunodeficiency virus (HIV)-infected adults (CD4 cell count, <200 cells/mm(3)) from 2 Ugandan centers were randomized to receive zidovudine-lamivudine plus abacavir or nevirapine. Virology was performed retrospectively on stored plasma samples at selected time points. In patients with HIV RNA levels >1000 copies/mL, the residual activity of therapy was calculated as the reduction in HIV RNA level, compared with baseline. Overall, HIV RNA levels were lower in the nevirapine group than in the abacavir group at 24 and 48 weeks (P < .001), although no differences were observed at weeks 4 and 12. Virological responses were similar in the 2 treatment groups for baseline HIV RNA level <100,000 copies/mL. The mean residual activity at week 48 was higher for abacavir in the presence of the typically observed resistance pattern of thymidine analogue mutations (TAMs) and M184V (1.47 log(10) copies/mL) than for nevirapine with M184V and nonnucleoside reverse-transcriptase inhibitor mutations, whether accompanied by TAMs (0.96 log(10) copies/mL) or not (1.18 log(10) copies/mL). There was more extensive genotypic resistance in both treatment groups than is generally seen in resource-rich settings. However, significant residual activity was observed among patients with virological failure, particularly those receiving zidovudine-lamivudine plus abacavir.