Pretreatment integrase strand transfer inhibitor resistance in North Carolina from 2010-2016

In Support of Breast-/Chestfeeding by People With HIV in High-Income Settings

Given that HIV can be transmitted through breastfeeding, historically, breastfeeding among women with HIV in the US and other resource-rich settings was discouraged. Formula feeding was the mandated feeding option out of concern for breast-milk transmission of HIV, which occurred in 16-24% of cases pre-antiretroviral therapy (pre-ART) use. In January 2023, the US Department of Health and Human Services' Perinatal Guidelines were revised to support shared decision-making for infant feeding choices. Updated clinical trials' data from resource-limited settings suggest the actual breastmilk HIV transmission rate in the context of maternal ART or neonatal postexposure prophylaxis is 0.3-1%. High-income countries are reporting more people with HIV breastfeeding their infants without cases of HIV transmission. We present the reasons for fully embracing breast-/chestfeeding as a viable, safe infant feeding option for HIV-exposed infants in high-income settings, while acknowledging unanswered questions and the need to continually craft more nuanced clinical guidance.

Full-Spectrum Surveillance of Pre-Treatment HIV Drug Resistance in Southeastern China

HIV drug resistance compromises the ability of anti-retroviral therapy (ART) to suppress viral replication, resulting in treatment failure. This study investigates the prevalence of pre-treatment drug resistance (PDR) in newly diagnosed individuals in a prosperous city (Wenzhou) in Southeastern China. A cross-sectional investigation was carried out among 473 newly diagnosed ART-naive HIV-1-infected individuals between January and December 2022. The protease-reverse transcriptase (PR-RT) region and integrase (IN) region of HIV-1 were amplified by two separately nested PCRs, followed by sequencing. Drug resistance mutations (DRMs) and drug resistance to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs) and integrase strand transfer inhibitors (INSTIs) were analyzed. The PDR prevalence was 6.5% [95% CI: 4.4-9.1] for any anti-retroviral drug, 0.9% [95% CI: 0.3-2.3] for NRTIs, 4.1% [95% CI: 2.5-6.5] for NNRTIs, 1.8% [95% CI: 0.8-3.6] for PIs and 0.5% [95% CI: 0.1-1.8] for INSTIs. According to the subtyping results of the PR-RT region, 11 different subtypes and 31 unique recombinant forms (URFs) were found. CRF07_BC was the dominant subtype (53.7%, 233/434), followed by CRF01_AE (25.3%, 110/434). V179D (1.6%) and K103N (1.4%) were the most predominant types of NNRTI DRMs. Q58E (1.2%) and M184V (0.7%) were the most frequent PI DRMs and NRTI DRMs, respectively. The INSTI-related DRMs Y143S (causes high-level resistance to RAL) and G163K (causes low-level resistance to EVG and RAL) were found in one patient each. Given the relatively high PDR prevalence of NNRTI (4.1%), non-NNRTI-based ART may be preferred in the future. It is recommended to include genotypic resistance testing before starting ART in regions where feasible.

Characterization of Human Immunodeficiency Virus-1 Transmission Clusters and Transmitted Drug-Resistant Mutations in Croatia from 2019 to 2022

Molecular epidemiology of HIV-1 infection is challenging due to the highly diverse HIV-genome. We investigated the genetic diversity and prevalence of transmitted drug resistance (TDR) followed by phylogenetic analysis in 270 HIV-1 infected, treatment-naïve individuals from Croatia in the period 2019-2022. The results of this research confirmed a high overall prevalence of TDR of 16.7%. Resistance to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside RTIs (NNRTIs), and protease inhibitors (PIs) was found in 9.6%, 7.4%, and 1.5% of persons, respectively. No resistance to integrase strand-transfer inhibitors (INSTIs) was found. Phylogenetic analysis revealed that 173/229 sequences (75.5%) were part of transmission clusters, and the largest identified was T215S, consisting of 45 sequences. Forward transmission was confirmed in several clusters. We compared deep sequencing (DS) with Sanger sequencing (SS) on 60 randomly selected samples and identified additional surveillance drug resistance mutations (SDRMs) in 49 of them. Our data highlight the need for baseline resistance testing in treatment-naïve persons. Although no major INSTIs were found, monitoring of SDRMs to INSTIs should be continued due to the extensive use of first- and second-generation INSTIs.

Preliminary report of transmitted drug resistance to integrase strand chain transfer inhibitors in treatment-naïve HIV infected patients

Transmitted Resistance exists in a newly diagnosed person who has not yet started their treatment. Our objective was to obtain a profile of HIV-1 resistance to integrase inhibitors in newly diagnosed treatment-naïve patients. Fifty people newly diagnosed with HIV-1 infection who had never received antiretroviral treatment were recruited. The complete integrase gene was amplified by nested RTPCR and the sequences obtained were analyzed with the ReCall and HIVdb v9.0. The overall prevalence transmitted due to mutations with some impact on integrase strand transfer inhibitors (INSTI) activity during the study period was 8%. The major E138K mutation was detected in only 1 patient and the secondary G163R mutation was detected in the other 3. The transmitted resistance for the first generation INSTI was 8% and for the second generation it was 0%. In Chile the resistance transmitted to INSTI is low and it is in according values detect in other part of the world.

National Landscape of Human Immunodeficiency Virus-Positive Deceased Organ Donors in the United States

BACKGROUND

Organ transplantation from donors with human immunodeficiency virus (HIV) to recipients with HIV (HIV D+/R+) presents risks of donor-derived infections. Understanding clinical, immunologic, and virologic characteristics of HIV-positive donors is critical for safety.

METHODS

We performed a prospective study of donors with HIV-positive and HIV false-positive (FP) test results within the HIV Organ Policy Equity (HOPE) Act in Action studies of HIV D+/R+ transplantation (ClinicalTrials.gov NCT02602262, NCT03500315, and NCT03734393). We compared clinical characteristics in HIV-positive versus FP donors. We measured CD4 T cells, HIV viral load (VL), drug resistance mutations (DRMs), coreceptor tropism, and serum antiretroviral therapy (ART) detection, using mass spectrometry in HIV-positive donors.

RESULTS

Between March 2016 and March 2020, 92 donors (58 HIV positive, 34 FP), representing 98.9% of all US HOPE donors during this period, donated 177 organs (131 kidneys and 46 livers). Each year the number of donors increased. The prevalence of hepatitis B (16% vs 0%), syphilis (16% vs 0%), and cytomegalovirus (CMV; 91% vs 58%) was higher in HIV-positive versus FP donors; the prevalences of hepatitis C viremia were similar (2% vs 6%). Most HIV-positive donors (71%) had a known HIV diagnosis, of whom 90% were prescribed ART and 68% had a VL <400 copies/mL. The median CD4 T-cell count (interquartile range) was 194/µL (77-331/µL), and the median CD4 T-cell percentage was 27.0% (16.8%-36.1%). Major HIV DRMs were detected in 42%, including nonnucleoside reverse-transcriptase inhibitors (33%), integrase strand transfer inhibitors (4%), and multiclass (13%). Serum ART was detected in 46% and matched ART by history.

CONCLUSION

The use of HIV-positive donor organs is increasing. HIV DRMs are common, yet resistance that would compromise integrase strand transfer inhibitor-based regimens is rare, which is reassuring regarding safety.

Epidemiology and Transmitted HIV-1 Drug Resistance among Treatment-Naïve Individuals in Israel, 2010-2018

Despite the low prevalence of HIV-1 in Israel, continuous waves of immigration may have impacted the local epidemic. We characterized all people diagnosed with HIV-1 in Israel in 2010–2018. The demographics and clinical data of all individuals (n = 3639) newly diagnosed with HIV-1 were retrieved. Subtypes, transmitted drug-resistance mutations (TDRM), and phylogenetic relations, were determined in >50% of them. In 39.1%, HIV-1 transmission was through heterosexual contact; 34.3% were men who have sex with men (MSM); and 10.4% were people who inject drugs. Many (>65%) were immigrants. Israeli-born individuals were mostly (78.3%) MSM, whereas only 9% of those born in Sub-Saharan Africa (SSA), Eastern Europe and Central Asia (EEU/CA), were MSM. The proportion of individuals from SSA decreased through the years 2010–2018 (21.1% in 2010–2012; 16.8% in 2016–2018) whereas those from EEU/CA increased significantly (21% in 2010–2012; 27.8% in 2016–2018, p < 0.001). TDRM were identified in 12.1%; 3.7, 3.3 and 6.6% had protease inhibitors (PI), nucleotide reverse transcriptase inhibitors (NRTI), and non-nucleoside reverse transcriptase inhibitors (NNRTI) TDRM, respectively, with the overall proportion remaining stable in the studied years. None had integrase TDRM. Subtype B was present in 43.9%, subtype A in 25.2% (A6 in 22.8 and A1 in 2.4%) and subtype C in 17.1% of individuals. Most MSM had subtype B. Subtype C carriers formed small clusters (with one unexpected MSM cluster), A1 formed a cluster mainly of locally-born patients with NNRTI mutations, and A6 formed a looser cluster of individuals mainly from EEU. Israelis, <50 years old, carrying A1, had the highest risk for having TDRM. In conclusion, an increase in immigrants from EEU/CA and a decrease in those from SSA characterized the HIV-1 epidemic in 2010–2018. Baseline resistance testing should still be recommended to identify TDRM, and improve surveillance and care.

Sustained HIV Viral Suppression With Dolutegravir, Tenofovir, and Emtricitabine as Initial Therapy Despite High-Level Transmitted Multiclass Resistance

Multiclass high-level transmitted HIV drug resistance is uncommon, and the selection of the optimal initial antiretroviral drug regimen may be challenging. We report a case of extensive transmitted multiclass resistance successfully treated with dolutegravir, tenofovir, and emtricitabine even though the baseline genotype demonstrated full susceptibility to only 1 drug class, integrase strand transfer inhibitors. Our case highlights both the high resistance barrier of dolutegravir and the residual antiviral activity of nucleoside reverse transcriptase inhibitors despite extensive resistance on genotype.

Integrase Strand Transfer Inhibitor Resistance in Integrase Strand Transfer Inhibitor-Naive Persons

There has been no systematic review of the prevalence of transmitted integrase strand transfer inhibitor (INSTI) resistance. We systematically searched the English-language PubMed database and GenBank to identify studies published since 2010 reporting 50 or more INSTI-naive HIV-1-infected adults undergoing integrase genotyping. We extracted data related to country, sample year, specimen type, sequencing method, and subtype. For studies with sequences in GenBank, we determined the prevalence of three categories of INSTI-associated resistance mutations: (1) nonpolymorphic INSTI-selected drug resistance mutations (DRMs) that we refer to as surveillance DRMs; (2) rarely selected nonpolymorphic INSTI-associated DRMs; and (3) common polymorphic accessory INSTI-selected DRMs. A total of 103 studies met inclusion criteria including 75 studies in GenBank containing integrase sequences from 16,481 INSTI-naive persons. The median sample year was 2013 (interquartile range: 2008-2014). The prevalence of INSTI surveillance DRMs, rarely selected DRMs, and common polymorphic accessory INSTI-selected DRMs were 0.5%, 0.8%, and 6.2%, respectively. There was no association between the presence of nonpolymorphic surveillance DRM and region, sample year, or subtype. Two surveillance DRMs, E138K and R263K occurred in 0.15% and 0.10% of naive sequences, respectively. Several lines of evidence suggested that the 0.5% prevalence of surveillance DRMs partly reflects the cumulative natural occurrence of these mutations in the absence of selective drug pressure. There was an unexplained temporal increase in the proportion of sequences with polymorphic accessory mutations. The prevalence of INSTI-associated surveillance DRMs is low even in regions where INSTIs have been a major component of antiretroviral therapy for several years. The presence of INSTI-associated surveillance DRMs in INSTI-naive persons likely results from actual cases of transmitted INSTI resistance and from a low background level reflecting the cumulative rare natural occurrence of several nonpolymorphic mutations.

Transmitted Drug Resistance Among HIV-1 Diagnoses in the United States, 2014-2018

BACKGROUND

Transmitted HIV drug resistance can threaten the efficacy of antiretroviral therapy (ART) and preexposure prophylaxis (PrEP). Drug resistance testing is recommended at entry to HIV care in the United States and provides valuable insight for clinical decision-making and population-level monitoring.

METHODS

We assessed transmitted drug resistance-associated mutation (TDRM) prevalence and predicted susceptibility to common HIV drugs among U.S. persons with HIV diagnosed during 2014-2018 who had a drug resistance test performed ≤3 months after HIV diagnosis and reported to the National HIV Surveillance System and who resided in 28 jurisdictions where ≥20% of HIV diagnoses had an eligible sequence during this period.

RESULTS

Of 50,747 persons in the analysis, 9,616 (18.9%) had ≥1 TDRM. TDRM prevalence was 0.8% for integrase strand transfer inhibitors (INSTI), 4.2% for protease inhibitors, 6.9% for nucleoside reverse transcriptase inhibitors, and 12.0% for non-nucleoside reverse transcriptase inhibitors. Most individual mutations had a prevalence <1.0% including M184V (0.9%) and K65R (0.1%); K103N was most prevalent (8.6%). TDRM prevalence did not increase or decrease significantly during 2014-2018 overall, for individual drug classes, or for key individual mutations except for M184V (12.9% increase per year, 95% CI=5.6-20.6).

CONCLUSIONS

TDRM prevalence overall and for individual drug classes remained stable during 2014-2018; transmitted INSTI resistance was uncommon. Continued population-level monitoring of INSTI and NRTI mutations, especially M184V and K65R, is warranted amidst expanding use of second-generation INSTI and PrEP.

Raltegravir versus efavirenz in antiretroviral-naive pregnant women living with HIV (NICHD P1081): an open-label, randomised, controlled, phase 4 trial

BACKGROUND

Although antiretroviral regimens containing integrase inhibitors rapidly suppress HIV viral load in non-pregnant adults, few published data from randomised controlled trials have compared the safety and efficacy of any integrase inhibitor to efavirenz when initiated during pregnancy. We compared safety and efficacy of antiretroviral therapy with either raltegravir or efavirenz in late pregnancy.

METHODS

An open-label, randomised controlled trial was done at 19 hospitals and clinics in Argentina, Brazil, South Africa, Tanzania, Thailand, and the USA. Antiretroviral-naive pregnant women (20-<37 weeks gestation) living with HIV were assigned to antiretroviral regimens containing either raltegravir (400 mg twice daily) or efavirenz (600 mg each night) plus lamivudine 150 mg and zidovudine 300 mg twice daily (or approved alternative backbone regimen), using a web-based, permuted-block randomisation stratified by gestational age and backbone regimen. The primary efficacy outcome was plasma HIV viral load below 200 copies per mL at (or near) delivery. The primary efficacy analysis included all women with a viral load measurement at (or near) delivery who had viral load of at least 200 copies per mL before treatment and no genotypic resistance to any study drugs; secondary analyses eliminated these exclusion criteria. The primary safety analyses included all women who received study drug, and their infants. This trial is registered with Clinicaltrials.gov, number NCT01618305.

FINDINGS

From Sep 5, 2013, to Dec 11, 2018, 408 women were enrolled (206 raltegravir, 202 efavirenz) and 394 delivered on-study (200 raltegravir, 194 efavirenz); 307 were included in the primary efficacy analysis (153 raltegravir, 154 efavirenz). 144 (94%) women in the raltegravir group and 129 (84%) in the efavirenz group met the primary efficacy outcome (absolute difference 10%, 95% CI 3-18; p=0·0015); the difference primarily occurred among women enrolling later in pregnancy (interaction p=0·040). Frequencies of severe or life-threatening adverse events were similar among mothers (30% in each group; 61 raltegravir, 59 efavirenz) and infants (25% in each group; 50 raltegravir, 48 efavirenz), with no treatment-related deaths.

INTERPRETATION

Our findings support major guidelines. The integrase inhibitor dolutegravir is currently a preferred regimen for the prevention of perinatal HIV transmission with raltegravir recommended as a preferred or alternative integrase inhibitor for pregnant women living with HIV.

FUNDING

Eunice Kennedy Shriver National Institute of Child Health and Human Development and National Institute of Allergy and Infectious Diseases.

Near Real-Time Identification of Recent Human Immunodeficiency Virus Transmissions, Transmitted Drug Resistance Mutations, and Transmission Networks by Multiplexed Primer ID-Next-Generation Sequencing in North Carolina

BACKGROUND

The identification of recent human immunodeficiency virus (HIV) 1 infections among people with new HIV diagnoses is important to both tailoring and assessing the impact of HIV-1 prevention strategies.

METHODS

We developed a multiplexed Primer ID-next-generation sequencing approach to identify recent infections by measuring the intrahost viral diversity over multiple regions of the HIV-1 genome, in addition to detecting drug resistance mutations (DRMs) and phylogenetically linked clusters. We summarize the field implementation of this all-in-one platform among persons with newly diagnosed HIV-1 by the North Carolina State Laboratory of Public Health in 2018.

RESULTS

Overall, recent infection was identified in 94 (35%) of 268 patients with new HIV diagnoses. People <30 years old, and people who inject drugs were more likely to have diagnoses of recent infection. The reverse-transcriptase region K103N was the most commonly detected DRM (prevalence, approximately 15%). We found a total of 28 clusters, and persons with recent infection were more likely to be cluster members than were those with chronic infections (P = .03).

CONCLUSIONS

We demonstrate the rapid identification of recent infection and pretreatment DRMs coupled with cluster analysis that will allow prioritization of linkage to care, treatment, and prevention interventions to those at highest risk of onward transmission.

Occurrence of the S230R integrase strand inhibitor mutation in a treatment-naïve individual case report

RATIONALE

Transmitted resistance to integrase strand inhibitors (INSTI) has been uncommon, but is slowly becoming more prevalent among those living with HIV. In an era with 2-drug regimens for antiretroviral therapy, transmitted resistance for INSTI is alarming.

PATIENT CONCERNS

A 28-year-old African American female was recently diagnosed with HIV during a 30-week prenatal visit.

DIAGNOSIS

HIV 4th generation test was positive as well as confirmation. Genotype was performed using next generation sequencing.

INTERVENTIONS

Patient was initially rapidly started on a dolutegravir based regimen and changed to a protease inhibitor regimen once her genotype reported an S230R mutation.

OUTCOMES

Patient became virally suppressed on antiretroviral therapy and delivered an HIV negative baby.

LESSONS

INSTI resistance testing should be done for treatment-naïve and INSTI-naïve persons, particularly when considering 2 drug INSTI based regimens.

Forecasting Prevalence of HIV-1 Integrase Strand Transfer Inhibitor (INSTI) Drug Resistance: A Modeling Study

BACKGROUND

Antiretroviral therapy (ART) is a cornerstone of HIV-1 treatment and provides significant health benefits for patients with responsive HIV-1 strains. Integrase strand transfer inhibitors (INSTIs) are the newest class of ART. Although most HIV-1 cases are responsive, a small number are already resistant. Here, we forecast the prevalence of INSTI resistance amid wide-spread use.

METHODS

We developed a stochastic model to simulate HIV-1 dynamics and INSTI resistance for raltegravir, elvitegravir, and dolutegravir. We forecast prevalence of INSTI resistance in adults living with HIV-1 over a 30-year period using parameter values and initial conditions that mimic HIV-1 dynamics Washington DC. We used the model to predict the amount of transmitted drug resistance (TDR) versus regimen-acquired drug resistance.

RESULTS

We forecast the prevalence of HIV-1 cases resistant to raltegravir as 0.41 (minimum: 0.21; maximum: 0.57), resistant to elvitegravir as 0.44 (minimum: 0.26; maximum: 0.60), and resistant to dolutegravir as 0.44 (minimum: 0.25; maximum: 0.65). Model output was greatly affected by the proportion of those living with HIV-1 on ART and the rate of converting from an INSTI-sensitive strain to an INSTI-resistant strain for chronically infected ART-experienced cases. We forecast that TDR will contribute minimally-if at all-to the overall proportion of resistant HIV-1 cases.

CONCLUSIONS

INSTI drug resistance has the potential to be a public health concern in the next 30 years. Although several parameters influence the predicted prevalence of INSTI drug resistance, TDR is unlikely to contribute substantially to future trends.

Transmitted drug resistance mutations and trends of HIV-1 subtypes in treatment-naïve patients: A single-centre experience

OBJECTIVES

Transmitted drug resistance (TDR) and HIV-1 genetic diversity may affect treatment efficacy and clinical outcomes. Here we describe the circulating viral subtypes and estimate the prevalence of drug resistance among antiretroviral therapy (ART)-naïve patients attending Sapienza University Hospital (Rome, Italy) from 2006-2017.

METHODS

Genotypic resistance testing (GRT) was performed on 668 ART-naïve patients for integrase (n = 52), protease and reverse transcriptase (n = 668) sequences.

RESULTS

Twenty-one different HIV-1 subtypes and circulating recombinant forms (CRFs) were identified. Subtype B was the most common (67.1%), followed by CRF02_AG (8.4%), and subtypes C and F (both 6.0%). A significantly increase in the proportion of non-B strains (P < 0.001) and the rate of non-Italian patients was observed over time. The overall prevalence of TDR was 9.4% (NRTI, 4.2%; NNRTI, 5.8%; and PI, 1.0%) and was higher in subtype B strains. Transmitted INSTI mutations (Q148H and G140S) responsible for high-level resistance to raltegravir and elvitegravir and intermediate resistance to dolutegravir and bictegravir were found, for the first time, in two individuals. Minor or accessory INSTI mutations were detected in 17.3% of patients. No significant decrease in the prevalence of TDR was documented over time.

CONCLUSION

The significant increase in non-B subtypes suggests that the molecular epidemiology of HIV-1 is changing. Detection of a major INSTI mutation in two ART-naïve patients highlights the importance of performing GRT before commencing treatment. This finding and the lack of a significant reduction in TDRs underline the importance of continuous surveillance of resistance mutations.

Prevalence of Human Immunodeficiency Virus-1 Integrase Strand Transfer Inhibitor Resistance in British Columbia, Canada Between 2009 and 2016: A Longitudinal Analysis

Background

Integrase strand transfer inhibitors (INSTIs) are highly efficacious and well tolerated antiretrovirals with fewer adverse side-effects relative to other classes of antiretrovirals. The use of INSTIs raltegravir, elvitegravir, and dolutegravir has increased dramatically over recent years. However, there is limited information about the evolution and prevalence of INSTI resistance mutations in clinical human immunodeficiency virus populations.

Methods

Human immunodeficiency virus-1-positive individuals ≥19 years were included if they received ≥1 dispensed prescription of antiretroviral therapy (ART) in British Columbia between 2009 and 2016 (N = 9358). Physician-ordered drug resistance tests were analyzed and protease inhibitor (PI), reverse-transcriptase inhibitor (RT), and INSTI resistance were defined as having ≥1 sample with a combined, cumulative score ≥30 by Stanford HIV Drug Resistance Algorithm version 7.0.1.

Results

Although most ART-treated individuals were tested for PI and RT resistance, INSTI resistance testing lagged behind the uptake of INSTIs among INSTI-treated individuals (11% in 2009; 34% in 2016). The prevalence of INSTI resistance was relatively low, but it increased from 1 to 7 per 1000 ART-treated individuals between 2009 and 2016 (P < .0001, R² = 0.98). Integrase strand transfer inhibitor resistance mutations increased at integrase codons 66, 97, 140, 148, 155, and 263.

Conclusions

The prevalence of INSTI resistance remains low compared with PI and RT resistance in ART-treated populations but is expanding with increased INSTI use.

New antiretroviral agent use affects prevalence of HIV drug resistance in clinical care populations

OBJECTIVE

To estimate the prevalence of HIV drug resistance over time and identify risk factors for multiclass resistance.

DESIGN

Prospective clinical cohort of HIV-infected patients at the University of North Carolina.

METHODS

Among antiretroviral therapy (ART)-experienced patients in care 2000-2016, we estimated annual prevalences of cumulative resistance, defined as at least one major mutation by drug class. Clinical data and multiple imputation were used when genotypic data were missing, and mutations were carried forward in time. We estimated resistance odds ratios comparing characteristics of patients in care in 2016.

RESULTS

A total of 3682 patients contributed 23 169 person-years. Prevalence of at least one major resistance mutation, irrespective of viral suppression, peaked in 2005 with 49% (95% confidence interval 46, 52) and decreased to 38% (35, 40) in 2016. Resistance to nucleoside reverse transcriptase inhibitors, protease inhibitors, and nonnucleoside reverse transcriptase inhibitors also peaked in 2005-2007 and decreased to 28 (26, 31), 14 (12, 16), and 27% (24, 29) in 2016, respectively. In 2016, prevalence of integrase strand transfer inhibitor (INSTI) resistance was 2% (1, 3) and triple-class resistance 10% (9, 12). Over the study period, cumulative resistance was frequent among patients with detectable viremia, but uncommon among patients initiating ART post-2007. Among 1553 patients in care in 2016, ART initiation at an older age, with an INSTI, and with higher CD4 cell counts were associated with resistance to fewer or no classes.

CONCLUSION

Prevalence of resistance to older ART classes has decreased in the last 10 years in this clinical cohort, whereas INSTI resistance has increased but remained very low. Patients with viremia continue to have a high burden of resistance even if they initiated ART recently.

Prevalence and Transmission Dynamics of HIV-1 Transmitted Drug Resistance in a Southeastern Cohort

Background

Transmitted drug resistance (TDR) compromises clinical management and outcomes. Transmitted drug resistance surveillance and identification of growing transmission clusters are needed in the Southeast, the epicenter of the US HIV epidemic. Our study investigated prevalence and transmission dynamics in North Carolina.

Methods

We analyzed surveillance drug resistance mutations (SDRMs) using partial pol sequences from patients presenting to 2 large HIV outpatient clinics from 1997 to 2014. Transmitted drug resistance prevalence was defined as ≥1 SDRMs among antiretroviral therapy (ART)–naïve patients. Binomial regression was used to characterize prevalence by calendar year, drug class, and demographic and clinical factors. We assessed the transmission networks of patients with TDR with maximum likelihood trees and Bayesian methods including background pol sequences (n = 15 246).

Results

Among 1658 patients with pretherapy resistance testing, ≥1 SDRMs was identified in 199 patients, with an aggregate TDR prevalence of 12% (95% confidence interval, 10% to 14%) increasing over time (P = .02). Resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs; 8%) was common, followed by nucleoside reverse transcriptase inhibitors (4%) and protease inhibitors (2%). Factors associated with TDR were being a man reporting sex with men, white race, young age, higher CD4 cell count, and being a member of a transmission cluster. Transmitted drug resistance was identified in 106 clusters ranging from 2 to 26 members. Cluster resistance was primarily NNRTI and dominated by ART-naïve patients or those with unknown ART initiation.

Conclusions

Moderate TDR prevalence persists in North Carolina, predominantly driven by NNRTI resistance. Most TDR cases were identified in transmission clusters, signifying multiple local transmission networks and TDR circulation among ART-naïve persons. Transmitted drug resistance surveillance can detect transmission networks and identify patients for enhanced services to promote early treatment.

Prevalence of Integrase Strand Transfer Inhibitors Resistance Mutations in Integrase Strand Transfer Inhibitors-Naive and -Experienced HIV-1 Infected Patients: A Single Center Experience

Integrase strand transfer inhibitor (InSTI) resistance rates are low. However, genotypic resistance test (GRT) is not routinely performed in many centers. The aim of this study is to evaluate the prevalence of InSTI-related mutations in our large cohort. We examined all integrase GRTs performed as part of routine clinical practice at Spedali Civili General Hospital, University of Brescia from 2011 to 2016. Analysis was performed through the Stanford HIV Drug Resistance Database. A total of 341 patients were included. Genotypic resistance assays were performed in naive (48), ART-experienced but InSTI-naive (114), and both ART-experienced/InSTI-experienced (179) patients. No major resistance-associated mutations (RAMs) were detected in patients never exposed to InSTIs. Of 179 samples from patients exposed to InSTIs (mostly to raltegravir [RAL]), the overall prevalence of major RAMs was 11.7%. Among them, 10 harbored N155H, 4 Q148H, 2 Q148R, 2 Y143C/S, and 2 T66A/I/T, respectively. A novel mutation at a recognized resistance site (E92K) was identified in one RAL-experienced patient. The overall prevalence of InSTI mutations in our cohort was low, particularly in naive patients indicating no transmitted RAMs, although in InSTIs-experienced patients the rate of RAMs was high (11.7%). We support an implementation of surveillance of InSTI resistance.

Integrase Strand Transfer Inhibitor Resistance Mutations in Antiretroviral Treatment-naïve Patients in Korea: a Prospective, Observational Study

The present study investigated prevalence of integrase strand transfer inhibitors (INSTI) resistance mutations in HIV-1-infected antiretroviral therapy (ART)-naïve patients in Korea. From 106 plasma samples, amplification and sequencing of integrase genes was performed, and major or minor mutations were calculated by the Stanford HIV drug resistance mutation interpretation algorithm. No major INSTI resistance mutations were found, and 14 minor mutations were detected in 13 (12.3%) patients. The present data support the recommendation that routine testing for INSTI resistance mutations before starting ART is not necessary.