Drug resistance prevalence in human immunodeficiency virus type 1 infected pediatric populations in Honduras and El Salvador during 1989-2009

Impact of lopinavir-ritonavir exposure in HIV-1 infected children and adolescents in Madrid, Spain during 2000-2014

Background

The most-used protease-inhibitor in children is Lopinavir-ritonavir (LPV/r), which provides durable suppression of viral load and increases CD4+T-counts. This study describes the virological outcome of the HIV-1-infected paediatric population exposed to LPV/r during 15 years in Spain.

Methodology

Patients from the Madrid Cohort of HIV-1-infected-children and adolescents exposed to LPV/r as different line therapy during 2000–2014 were selected. The baseline epidemiological-clinical features, viral suppression, changes in CD4+T-CD8+T cell counts and drug susceptibility were recorded before and during LPV/r exposure. Drug resistance mutations (DRM) were identified in viruses from samples collected until 2011. We predicted drug susceptibility to 19 antiretrovirals among those carrying DRM using the Stanford′s HIVdb Algorithm.

Results

A total of 199 (37.3%) of the 534 patients from the cohort were exposed to LPV/r during 2000–2014 in first (group 1), second (group 2) or more line-therapies (group 3). Patients were mainly Spaniards (81.9%), perinatally infected (96.5%) with subtype-B (65.3%) and HIV-diagnosed before year 2000 (67.8%). The mean age at first LPV/r exposure was 9.7 years. After protease-inhibitor exposure, viral suppression was higher in groups 1 and 2 than in group 3. Viral suppression occurred in 87.5%, 68.6% and 64.8% patients from groups 1, 2 and 3, respectively. Among the 64 patients with available resistance data during LPV/r treatment, 27(42.3%) carried DRM to protease-inhibitor, 28 (58.3%) to reverse-transcriptase-inhibitors and 21 (43.7%) to non-reverse-transcriptase-inhibitors. Darunavir/ritonavir, atazanavir-ritonavir and tipranavir/ritonavir presented the highest susceptibility and nelfinavir the lowest.

Conclusions

A better lymphocyte recovering occurred when protease-inhibitor was taken as part of a first-line regimen and a higher number of patients reached viral suppression. The least compromised antiretrovirals for rescue antiretroviral regimens, according to DRM in the LPV/r-exposed-paediatric cohort, were mainly the new protease inhibitors.

Drug resistance in the HIV-1-infected paediatric population worldwide: a systematic review

BACKGROUND

Drug resistance monitoring of the paediatric HIV-1-infected population is required to optimize treatment success and preserve future treatment options.

OBJECTIVES

To explore the current knowledge of HIV drug resistance (HIVDR) in naive and pretreated HIV-1-infected paediatric populations across diverse settings and sampling time periods.

METHODS

PubMed database screened until May 2013. We selected publications including data on transmitted (TDR) and acquired drug resistance mutation (DRM) rates and/or pol sequences for HIVDR testing in paediatric patients. We recorded the children's country, age, study period, number of children with pol sequences, presence or absence of antiretroviral treatment (ART) at sampling time, viral region sequenced, HIVDR rate to the three main drug classes (single, double or triple), the considered resistance mutation list and performed assay, specimen type, HIV-1 variants and subtyping methodology when available.

RESULTS

Forty-one selected studies showed HIVDR data from 2538 paediatric HIV-1-infected patients (558 naive and 1980 pretreated) from 30 countries in Africa (11), Asia (6), America (10) and Europe (3). Both TDR and DRM prevalence were reported in 9 studies, only TDR in 6 and only DRM in 26. HIVDR prevalence varied across countries and periods. Most studies used in-house resistance assays using plasma or infected cells. HIV-1 non-B variants were prevalent in 18 paediatric cohorts of the 24 countries with reported subtypes. Only five countries (Uganda, Spain, the UK, Brazil and Thailand) presented resistance data in ≥200 patients.

CONCLUSIONS

Systematic and periodic studies among infected children are crucial to design a more suitable first- or second-line therapy.

Human immunodeficiency virus type 1 (HIV-1) subtype B epidemic in Panama is mainly driven by dissemination of country-specific clades

The Human immunodeficiency virus type-1 (HIV-1) subtype B is the most predominant clade in Central America; but information about the evolutionary history of this virus in this geographic region is scarce. In this study, we reconstructed the spatiotemporal and population dynamics of the HIV-1 subtype B epidemic in Panama. A total of 761 HIV-1 subtype B pol sequences obtained in Panama between 2004 and 2013 were combined with subtype B pol sequences from the Americas and Europe. Maximum Likelihood phylogenetic analyses revealed that HIV-1 subtype B infections in Panama derived from the dissemination of multiple founder viruses. Most Panamanian subtype B viruses (94.5%) belong to the pandemic viral strain proposed as originated in the US, whereas others (5.5%) were intermixed among non-pandemic Caribbean strains. The bulk (76.6%) of subtype B sequences from Panama grouped within 12 country-specific clades that were not detected in other Central American countries. Bayesian coalescent-based analyses suggest that most Panamanian clades probably originated between the early 1970s and the early 1980s. The root location of major Panamanian clades was traced to the most densely populated districts of Panama province. Major Panamanian clades appear to have experienced one or two periods of exponential growth of variable duration between the 1970s and the 2000s, with median growth rates from 0.2 to 0.4 year⁻¹. Thus, the HIV-1 subtype B epidemic in Panama is driven by the expansion of local viral strains that were introduced from the Caribbean and other American countries at an early stage of the AIDS pandemic.

HIV-1 drug resistance prevalence, drug susceptibility and variant characterization in the Jacobi Medical Center paediatric cohort, Bronx, NY, USA

OBJECTIVES

With the advent of combined antiretroviral therapy (cART), perinatally HIV-infected children are surviving into adolescence and beyond. However, drug resistance mutations (DRMs) compromise viral control, affecting the long-term effectiveness of ART. The aims of this study were to detect and identify DRMs in a HIV-1 infected paediatric cohort.

METHODS

Paired plasma and dried blood spots (DBSs) specimens were obtained from HIV-1 perinatally infected patients attending the Jacobi Medical Center, New York, USA. Clinical, virological and immunological data for these patients were analysed. HIV-1 pol sequences were generated from samples to identify DRMs according to the International AIDS Society (IAS) 2011 list.

RESULTS

Forty-seven perinatally infected patients were selected, with a median age of 17.7 years, of whom 97.4% were carrying subtype B. They had a mean viral load of 3143 HIV-1 RNA copies/mL and a mean CD4 count of 486 cells/μL at the time of sampling. Nineteen patients (40.4%) had achieved undetectable viraemia (< 50 copies/mL) and 40.5% had a CD4 count of > 500 cells/μL. Most of the patients (97.9%) had received cART, including protease inhibitor (PI)-based regimens in 59.6% of cases. The DRM prevalence was 54.1, 27.6 and 27.0% for nucleoside reverse transcriptase inhibitors (NRTIs), PIs and nonnucleoside reverse transcriptase inhibitors (NNRTIs), respectively. Almost two-thirds (64.9%) of the patients harboured DRMs to at least one drug class and 5.4% were triple resistant. The mean nucleotide similarity between plasma and DBS sequences was 97.9%. Identical DRM profiles were present in 60% of plasma-DBS paired sequences. A total of 30 DRMs were detected in plasma and 26 in DBSs, with 23 present in both.

CONCLUSIONS

Although more perinatally HIV-1-infected children are reaching adulthood as a result of advances in cART, our study cohort presented a high prevalence of resistant viruses, especially viruses resistant to NRTIs. DBS specimens can be used for DRM detection.

Long-term virologic response and genotypic resistance mutations in HIV-1 infected Kenyan children on combination antiretroviral therapy

BACKGROUND

HIV-infected children may require the use of combination antiretroviral treatment (cART) into adulthood. However, regimens are limited to first line and second line in many African settings. Therefore, understanding the long-term rate of virologic failure and drug resistance during prolonged antiretroviral treatment is important for establishing treatment strategies in African pediatric cohorts.

METHODS

Children aged 18 months to 12 years initiated first-line cART and were followed every 1-3 months, for up to 5.5 years. Treatment was switched to second-line cART based on clinical and immunologic criteria according to national guidelines. Virologic failure was determined retrospectively as defined by ≥2 viral loads >5000 copies per milliliter. Drug resistance was assessed during viral failure by population-based sequencing.

RESULTS

Among 100 children on first-line cART followed for a median of 49 months, 34% children experienced virologic failure. Twenty-three (68%) of the 34 children with viral failure had detectable resistance mutations, of whom 14 (61%) had multiclass resistance. Fourteen (14%) children were switched to second-line regimens and followed for a median of 28 months. Retrospective analysis revealed that virologic failure had occurred at a median of 12 months before switching to second line. During prolonged first-line treatment in the presence of viral failure, additional resistance mutations accumulated; however, only 1 (7%) of 14 children had persistent viremia during second-line treatment.

DISCUSSION

Virologic suppression was maintained on first-line cART in two-thirds of HIV-infected children for up to 5 years. Switch to second line based on clinical/immunologic criteria occurred ∼1 year after viral failure, but the delay did not consistently compromise second-line treatment.

Reconstructing the timing and dispersion routes of HIV-1 subtype B epidemics in the Caribbean and Central America: a phylogenetic story

The Caribbean and Central America are among the regions with highest HIV-1B prevalence worldwide. Despite of this high virus burden, little is known about the timing and the migration patterns of HIV-1B in these regions. Migration is one of the major processes shaping the genetic structure of virus populations. Thus, reconstruction of epidemiological network may contribute to understand HIV-1B evolution and reduce virus prevalence. We have investigated the spatio-temporal dynamics of the HIV-1B epidemic in The Caribbean and Central America using 1,610 HIV-1B partial pol sequences from 13 Caribbean and 5 Central American countries. Timing of HIV-1B introduction and virus evolutionary rates, as well as the spatial genetic structure of the HIV-1B populations and the virus migration patterns were inferred. Results revealed that in The Caribbean and Central America most of the HIV-1B variability was generated since the 80 s. At odds with previous data suggesting that Haiti was the origin of the epidemic in The Caribbean, our reconstruction indicated that the virus could have been disseminated from Puerto Rico and Antigua. These two countries connected two distinguishable migration areas corresponding to the (mainly Spanish-colonized) Easter and (mainly British-colonized) Western islands, which indicates that virus migration patterns are determined by geographical barriers and by the movement of human populations among culturally related countries. Similar factors shaped the migration of HIV-1B in Central America. The HIV-1B population was significantly structured according to the country of origin, and the genetic diversity in each country was associated with the virus prevalence in both regions, which suggests that virus populations evolve mainly through genetic drift. Thus, our work contributes to the understanding of HIV-1B evolution and dispersion pattern in the Americas, and its relationship with the geography of the area and the movements of human populations.

Transmitted drug-resistance in human immunodeficiency virus-infected adult population in El Salvador, Central America

El Salvador harbours one of the largest Central American human immunodeficiency virus (HIV) epidemics, but few studies have analysed it in depth. Here, we describe the presence of transmitted drug resistance (TDR) and HIV variants in the HIV-infected adult population in El Salvador. Dried blood spots from 119 HIV-infected antiretroviral-naive adults attended in El Salvador were collected in 2011. The TDR was assessed according to the list recommended by the WHO. HIV-1 variants were described using phylogeny. Pol sequences could be amplified in 88 patients (50.6% men), with a mean age of 35 years. Almost all (96.7%) were infected with HIV through sexual practice and 58.7% were recently diagnosed. The mean CD4(+) count was 474 cells/mm(3) and 43.1% and 15.5% of patients showed moderate (<500 CD4 cells) or severe (<200) immune suppression, respectively. HIV-1 viral load was >100 000 copies/mL in 24.7% of patients and <2000 copies/mL in 9.1%. Five samples (5.7%) harboured any TDR mutation: 2.3% for nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI), and 1.4% for protease inhibitor (PI). All showed only one TDR single-class resistance mutation: M184I (two cases) for NRTI, K101E and K103N for NNRTI and L23I for PI. All viruses excepting one (URF_BG) belonged to subtype B. No phylogenetic TDR networks were found. In conclusion, we report a TDR prevalence of 5.7% in El Salvador, lower than in other Central American studies. Periodical studies are essential to monitor and prevent TDR emergence in low-income and middle-income regions. Also, more efforts are needed to promote early diagnosis and prevention of infection in El Salvador.

[Dried blood spots for monitoring HIV infection in Public Health Programs in developing countries]

As access to antiretroviral treatment increases in the developing countries, efforts towards making it easier and less costly to collect, store, and deliver the biological samples to reference laboratories, where the serological and genetic diagnosis techniques are performed, have become a high priority. Blood sampling on filter papers is an inexpensive and practical alternative to plasma for antiretroviral treatment monitoring in countries with limited resources and no access to cold chains or refrigeration. The main clinical applications and uses of blood-sampling onto filter papers (dried blood spots [DBS]) are reviewed, focusing on how these can be applied in monitoring HIV infection, particularly for use in National Health Programs in developing countries, or in resource-limited settings. A review is presented of studies that have used the DBS technique for quantifying viral load, analysis of antiretroviral drug-resistance mutations, early infant diagnosis, adult serological diagnosis, detection of viral p24 antigen, and molecular epidemiology of HIV-1, in different geographical locations. Those variables that could affect the use of DBS, particularly in the HIV field, as well as explaining how these procedures can be optimised to increase their sensitivity are also reviewed. The aim of this study was to review the advantages of implementing the DBS technique in the HIV field, especially in resource-constrained regions.

Drug resistance prevalence and HIV-1 variant characterization in the naive and pretreated HIV-1-infected paediatric population in Madrid, Spain

BACKGROUND

Drug resistance mutations affect antiretroviral therapy (ART) effectiveness in HIV-1-infected children, compromising long-term therapy. HIV-1 variants and drug resistance mutations were identified in HIV-infected children from Madrid, Spain.

METHODS

Patients from the Madrid cohort of HIV-infected children (1993-2009) with available pol sequences or infected samples stored at the Spanish HIV-1 BioBank were selected. Specimens were used to perform new pol sequences when not available. HIV-1 variants were characterized by phylogenetic analysis. Resistance mutations were identified according to the International AIDS Society-USA list (2009).

RESULTS

In 198 patients, pol sequences were recovered from routine resistance testing (n = 98) or newly performed using stored plasma, lymphocytes or DNA (n = 100). Patients were mostly Europeans (90%), with moderate to severe AIDS symptoms (65%), on ART (85%) when the specimen was sequenced and infected by subtype B (90%). Among the 19 HIV-1 non-B variants found, 58% were recombinants (8CRF02_AG, 1CRF08_BC, 1CRF12_BF and 1CRF13_cpx) and the rest were 'pure' non-B subtypes (1A2, 2C, 2D, 1F1, 1G and 1H). Transmitted drug resistance (TDR) mutations were detected in 13% of naive children; 4%, 7% and 10% for protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs), respectively. Global resistance prevalence was higher (66%) among ART-exposed children; 37% for PIs, 54% for NRTIs and 35% for NNRTIs.

CONCLUSIONS

HIV-1 non-B variants infected 10% of the cohort during 1993-2009. Resistant viruses were present in 26.5% and 66% of naive and pretreated children, respectively. Our data suggest that TDR prevalence in children could be higher than that reported in adults in Spain. The provided data will help to improve clinical management of HIV-infected children in Spain.