Prevalence of drug-resistant and nonsubtype B HIV strains in antiretroviral-naïve, HIV-infected individuals in New York State

Prevalence of HIV-1 transmitted drug resistance in the incarcerated population

OBJECTIVES

The aim of the study was to determine the prevalence of transmitted drug resistance (TDR)-associated mutations among treatment-naïve, incarcerated individuals with HIV-1 infection in the USA as well as the class TDR and antiretroviral (ARV) mutations present at baseline.

METHODS

Patients over the age of 18 years were included in the study if they had been diagnosed with HIV infection, if their HIV infection was managed through telemedicine and if they were incarcerated in the State of Illinois Department of Corrections between 10 July 2010 and 29 April 2016. Additionally, the patients were required to have a documented genotype and be ARV-naïve. A medical chart review was conducted to assess demographic information, disease burden, and risk factors for acquiring the virus.

RESULTS

The inclusion criteria were met for 105 patients. A total of 24 patients (23%) had a clinically significant mutation associated with resistance to any drug class. The prevalence of mutations conferring clinically significant resistance was 19% for nonnucleoside reverse transcriptase inhibitors (NNRTIs), 18% for nucleoside reverse transcriptase inhibitors (NRTIs), and 4% for protease inhibitors (PIs). Five per cent of patients had dual-class TDR to both NRTI and NNRTI drug classes and 2% of patients had mutations to both NNRTI and PI drug classes. There was no significant increase in the prevalence of clinically relevant drug resistance mutations based on demographics, burden of disease, or risk factors for acquiring the virus.

CONCLUSIONS

A high prevalence of TDR was identified in the ARV-naïve incarcerated population. The results of this study indicate an increased prevalence of TDR in a largely unstudied incarcerated population, demonstrating the need for increased monitoring of resistance in HIV-infected patients world-wide.

HIV-1 drug resistance and resistance testing

The global scale-up of antiretroviral (ARV) therapy (ART) has led to dramatic reductions in HIV-1 mortality and incidence. However, HIV drug resistance (HIVDR) poses a potential threat to the long-term success of ART and is emerging as a threat to the elimination of AIDS as a public health problem by 2030. In this review we describe the genetic mechanisms, epidemiology, and management of HIVDR at both individual and population levels across diverse economic and geographic settings. To describe the genetic mechanisms of HIVDR, we review the genetic barriers to resistance for the most commonly used ARVs and describe the extent of cross-resistance between them. To describe the epidemiology of HIVDR, we summarize the prevalence and patterns of transmitted drug resistance (TDR) and acquired drug resistance (ADR) in both high-income and low- and middle-income countries (LMICs). We also review to two categories of HIVDR with important public health relevance: (i) pre-treatment drug resistance (PDR), a World Health Organization-recommended HIVDR surveillance metric and (ii) and pre-exposure prophylaxis (PrEP)-related drug resistance, a type of ADR that can impact clinical outcomes if present at the time of treatment initiation. To summarize the implications of HIVDR for patient management, we review the role of genotypic resistance testing and treatment practices in both high-income and LMIC settings. In high-income countries where drug resistance testing is part of routine care, such an understanding can help clinicians prevent virological failure and accumulation of further HIVDR on an individual level by selecting the most efficacious regimens for their patients. Although there is reduced access to diagnostic testing and to many ARVs in LMIC, understanding the scientific basis and clinical implications of HIVDR is useful in all regions in order to shape appropriate surveillance, inform treatment algorithms, and manage difficult cases.

Prevalence of Transmitted HIV Drug Resistance Among Recently Infected Persons in San Diego, CA 1996-2013

BACKGROUND

Transmitted drug resistance (TDR) remains an important concern when initiating antiretroviral therapy (ART). Here, we describe the prevalence and phylogenetic relationships of TDR among ART-naive, HIV-infected individuals in San Diego from 1996 to 2013.

METHODS

Data were analyzed from 496 participants of the San Diego Primary Infection Cohort who underwent genotypic resistance testing before initiating therapy. Mutations associated with drug resistance were identified according to the WHO-2009 surveillance list. Network and phylogenetic analyses of the HIV-1 pol sequences were used to evaluate the relationships of TDR within the context of the entire cohort.

RESULTS

The overall prevalence of TDR was 13.5% (67/496), with an increasing trend over the study period (P = 0.005). TDR was predominantly toward nonnucleoside reverse transcriptase inhibitors (NNRTIs) [8.5% (42/496)], also increasing over the study period (P = 0.005). By contrast, TDR to protease inhibitors and nucleos(t)ide reverse transcriptase inhibitors were 4.4% (22/496) and 3.8% (19/496), respectively, and did not vary with time. TDR prevalence did not differ by age, gender, race/ethnicity, or risk factors. Using phylogenetic analysis, we identified 52 transmission clusters, including 8 with at least 2 individuals sharing the same mutation, accounting for 23.8% (16/67) of the individuals with TDR.

CONCLUSIONS

Between 1996 and 2013, the prevalence of TDR significantly increased among recently infected ART-naive individuals in San Diego. Around one-fourth of TDR occurred within clusters of recently infected individuals. These findings highlight the importance of baseline resistance testing to guide selection of ART and for public health monitoring.

Antiretroviral treatment failure, drug resistance, and subtype diversity in the only pediatric HIV clinic in Rhode Island

BACKGROUND

Drug resistance development in the human immunodeficiency virus (HIV)-infected pediatric population in the United States can impact long-term antiretroviral therapy (ART) efficacy. Limited formularies and adherence constraints in children jeopardize lifelong-needed ART.

METHODS

We examined treatment failure, drug resistance, and their correlates in ART-naive and ART-experienced children attending the pediatric HIV clinic in Rhode Island between 1991 and 2012. Pol sequences were obtained for phylogenetic, subtype, and resistance analyses. Associations between selected covariates and virologic failure and resistance were evaluated using generalized additive models and Fisher exact tests.

RESULTS

Data were available for all 56 clinic-attending children. At diagnosis, 33% were aged <1 year, 31% aged 1-4 years, and 37% aged ≥ 5 years; 54% were male, 73% black or Hispanic, 55% US-born, 20% refugees, and 64% perinatally infected. Of 44 ART-experienced children, 57% had virologic failure, most never virologically suppressed. Failure was associated with missed appointments (P = .05) and missed doses (P < .01). Of 40 children with available genotypes, 35% were infected with non-B subtypes; 6% of ART-naive children had resistance; and 73% of ART-experienced children had ≥ 1 major mutation: (16% conferring triple-class, 47% dual-class, and 37% single-class resistance). An epidemiologically confirmed resistance transmission from a perinatally infected teenage male to a newly infected teenage female was demonstrated.

CONCLUSIONS

We report high HIV type 1 diversity, extensive drug resistance among ART-experienced children, and horizontal transmission of resistance in the Rh ode Island pediatric HIV clinic. As HIV-infected children mature into adulthood, close monitoring of ART, adherence, and diagnosis disclosure are essential to optimize patient care.

Burden of nonnucleoside reverse transcriptase inhibitor resistance in HIV-1-infected patients: a systematic review and meta-analysis

The prevalence of HIV drug resistance varies with geographic location, year, and treatment exposure. This study generated yearly estimates of nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance in treatment-naive (TN) and treatment-experienced (TE) patients in the United States (US), Europe (EU), and Canada. Studies reporting NNRTI resistance identified in electronic databases and 11 conferences were analyzed in three groups: (1) TN patients in one of four geographic regions [US, Canada, EU countries with larger surveillance networks ("EU1"), and EU countries with fewer data ("EU2")]; (2) TE patients from any region; and (3) TN patients failing NNRTI-based treatments in clinical trials. Analysis data included 158 unique studies from 22 countries representing 84 cohorts of TN patients, 21 cohorts of TE patients, and 8 trials reporting resistance at failure. From 1995 to 2000, resistance prevalence in TN patients increased in US and EU1 from 3.1% to 7.5% and 0.8% to 3.6%, respectively. Resistance in both regions stabilized in 2006 onward. Little resistance was identified in EU2 before 2000, and increased from 2006 (5.0%) to 2010 (13.7%). One TN Canadian study was identified and reported resistance of 8.1% in 2006. Half of TN clinical trial patients had resistance after treatment failure at weeks 48-144. Resistance in TE patients increased from 1998 (10.1%) to 2001 (44.0%), then decreased after 2004. Trends in NNRTI resistance among TN patients show an increased burden in the US and some EU countries compared to others. These findings signify a need for alternate first-line treatments in some regions.

Phylogenetic and geospatial evaluation of HIV-1 subtype diversity at the largest HIV center in Rhode Island

Individuals infected with HIV-1 non-B subtypes are understudied in the United States. Their characterization may augment prevention and treatment interventions. We examined the regional molecular epidemiology of non-B subtypes using a combined phylogenetic and geospatial approach. HIV-1 pol sequences and clinical data obtained for routine clinical care were aggregated from 2004 to 2011 at the largest HIV center in Rhode Island. Subtyping was performed by neighbor-joining and maximum-likelihood phylogeny and compared across eight commonly used tools (HIVdb, REGA, RIP, NCBI, Geno2Pheno, EuResist, jpHMM and STAR) using proportional odds ordinal regression. Individuals with non-B subtypes were characterized according to demographics and risk factors for infection, intra-subtype clustering by maximum-likelihood phylogeny, and geospatial hotspot analysis using Getis-Ord Gi(∗) statistics. Of 1277 unique sequences, phylogenetic subtyping demonstrated 8.3% (N=106, 95% CI 6.8-10%) non-B subtypes and circulating recombinant forms (CRFs): CRF02_AG=46; A=15; C=15; CRF01_AE=6; CRF06_CPX=5; CRF14_BG=5; G=3; CRF43_02G=3; D=3; CRF24_BG=3; CRF11_CPX=1; F1=1. Compared to phylogeny, Geno2Pheno was the most concordant (86% exact match) followed by REGA (85%), EuResist (85%) and STAR (82%). Of 106 individuals with non-B subtypes, 50% were male, 71% acquired infection through heterosexual transmission; 76%, were born in Africa, 6% Southeast Asia, 5% the United States, 3% Central America, 1% Europe, and 9% unknown. Eighty percent of CRF02_AG, 93% of A and 87% of C sequences were from African-born individuals. Twenty-two percent of non-B subtypes formed transmission clusters, including a significant number of younger individuals with perinatally-acquired infection. Geospatial analyses revealed hotspots of B and non-B subtypes in the state capital with a more concentrated focus among non-B subtypes. Molecular examination of regional HIV diversity revealed a larger than expected non-subtype B infected population, mostly born in Africa, with low ongoing regional transmission. Phylogenetic and geospatial characterization of infection clusters is helpful to identify targets for treatment and prevention interventions.

Large-scale analysis of the prevalence and geographic distribution of HIV-1 non-B variants in the United States

The genetic diversity of human immunodeficiency virus type 1 (HIV-1) has significant implications for diagnosis, vaccine development, and clinical management of patients. Although HIV-1 subtype B is predominant in the United States, factors such as global travel, immigration, and military deployment have the potential to increase the proportion of non-subtype B infections. Limited data are available on the prevalence and distribution of non-B HIV-1 strains in the United States. We sought to retrospectively examine the prevalence, geographic distribution, diversity, and temporal trends of HIV-1 non-B infections in samples obtained by ARUP Laboratories, a national reference laboratory, from all regions of the United States. HIV-1 pol sequences from 24,386 specimens collected from 46 states between 2004 and September 2011 for drug resistance genotyping were analyzed using the REGA HIV-1 Subtyping Tool, version 2.0. Sequences refractory to subtype determination or reported as non-subtype B by this tool were analyzed by PHYLIP version 3.5 and Simplot version 3.5.1. Non-subtype B strains accounted for 3.27% (798/24,386) of specimens. The 798 non-B specimens were received from 37 states and included 5 subtypes, 23 different circulating recombinant forms (CRFs), and 39 unique recombinant forms (URFs). The non-subtype B prevalence varied from 0% in 2004 (0/54) to 4.12% in 2011 (201/4,884). This large-scale analysis reveals that the diversity of HIV-1 in the United States is high, with multiple subtypes, CRFs, and URFs circulating. Moreover, the geographic distribution of non-B variants is widespread. Data from HIV-1 drug resistance testing have the potential to significantly enhance the surveillance of HIV-1 variants in the United States.

Transmitted antiretroviral drug resistance and thumb subdomain polymorphisms among newly HIV type 1 diagnosed patients infected with CRF01_AE and CRF07_BC virus in Guangdong Province, China

The aim of this study was to elucidate the prevalence of transmitted drug-resistant (TDR) mutations and reverse transcriptase (RT) thumb subdomain polymorphisms in CRF01_AE and CRF07_BC virus among newly diagnosed, therapy-naive HIV-1 patients in Guangdong Province, China. One hundred and sixty-four samples were collected in the Guangzhou Eighth People's Hospital. The entire protease gene and 300 codons of the entry part of the reverse transcriptase were amplified and sequenced. Furthermore, genotypic drug resistance, polymorphisms, and their phylogeny were analyzed. According to eligibility criteria, seven samples were excluded, and 119 of 157 (75.8%) samples (84 CRF01_AE and 35 CRF07_BC) were amplified and sequenced successfully. The prevalence of TDR identified in the present study was 6.7% [8/119, 95% confidence interval (CI) 1.8-11.6%]. Three major resistance mutations, K103N, M184V, and Y188L, each of which caused more than one drug resistance, appeared in only two patients; the prevalence [1.7 % (2/119)] was relatively low. Until now, this is the first observation of the five newly identified accessory mutations, V35T, K43E, V60I, K122E, and E203D, and seven thumb subdomain polymorphisms, A272P, K277R, K281R, T286A, E291D, V292I, and I293V, in the RT gene in China. These findings provide useful information for guidance on the antiretroviral therapy (ART) policy in China where therapeutic options are still limited.

Prevalence of sexually acquired antiretroviral drug resistance in a community sample of HIV-positive men who have sex with men in New York City

To examine antiretroviral (ARV) drug resistance, we recruited a community sample (n=347) of sexually active HIV-positive men who have sex with men (MSM) in New York City, each of whom completed a structured interview and donated a blood sample for HIV genotyping. Participants reported high levels of sexual activity, with 94.6% reporting at least one sexual contact in the past month, and an average of 3.13 partners during this time. Anal intercourse was common, with 70.7% reporting at least one act of insertive anal intercourse (21% of whom reported ejaculating inside their partner without a condom) and 62.1% reporting at least one act of receptive anal intercourse during this time (22.6% of whom received ejaculate without a condom). Seventeen percent reported having sex with a woman in the past year. Although 17.4% of participants reported having ever injected drugs, no association was found between injection and antiretroviral resistance. Average HIV diagnosis was 12.1 years prior to the interview, and 92.1% had taken ARV medication. Sexually transmitted infections (STIs) were widely reported, with 78% having been diagnosed with an STI since being diagnosed with HIV. A genotype was obtained for 188 (54.7%) of the samples and 44.7% revealed mutations conferring resistance to at least one ARV. Resistance to at least one ARV within a given class of medication was most common for nucleoside reverse transcriptase inhibitors (30.3%) and non-nucleoside reverse transcriptase inhibitors (27.7%) and least common for protease inhibitors (18.1%). The combination of high prevalence of antiretroviral resistance and risky sexual practices makes transmission between sex partners a likely mode of acquisition.

Transmitted drug resistance in nonsubtype B HIV-1 infection

HIV-1 nonsubtype B variants account for the majority of HIV infections worldwide. Drug resistance in individuals who have never undergone antiretroviral therapy can lead to early failure and limited treatment options and, therefore, is an important concern. Evaluation of reported transmitted drug resistance (TDR) is challenging owing to varying definitions and study designs, and is further complicated by HIV-1 subtype diversity. In this article, we discuss the importance of various mutation lists for TDR definition, summarize TDR in nonsubtype B HIV-1 and highlight TDR reporting and interpreting challenges in the context of HIV-1 diversity. When examined carefully, TDR in HIV-1 non-B protease and reverse transcriptase is still relatively low in most regions. Whether it will increase with time and therapy access, as observed in subtype-B-predominant regions, remains to be determined.

Understanding transmitted HIV resistance through the experience in the USA

Transmitted drug resistance is an emerging phenomenon with important clinical and public health implications. It has been reported in 3.4% to 26% of HIV-infected persons in the USA. Most cases affect non-nucleoside reverse transcriptase inhibitors or nucleos(t)ide reverse transcriptase inhibitors. Transmitted protease inhibitor or multi-class resistance is uncommon, occurring in <5% of cases. The genital tract may function as a reservoir of transmissible drug-resistant variants or a site for low-level viral replication at a time plasma HIV is suppressed. Transmitted drug-resistant HIV variants, including those that exist in very low titers (minority populations), are associated with suboptimal virologic response to initial antiretroviral therapy. Baseline resistance testing, preferably genotype, appears to be cost-effective and is recommended for all treatment-naïve patients in the USA, although prospective trials have not been performed. It appears transmitted drug resistance is still relatively low in developing countries, but there is a dearth of information.