Next-Generation Sequencing to Help Monitor Patients Infected with HIV: Ready for Clinical Use?

Rapid HIV-1 drug resistance testing in a resource limited setting: the Pan Degenerate Amplification and Adaptation assay (PANDAA)

Introduction

pre-treatment drug resistance (PDR) can compromise the 3^rd 95-95-95 global target for viral load suppression. The high complexity and cost of genotyping assays limits routine testing in many resource limited settings (RLS). We assessed the performance of a rapid HIV-1 drug resistance assay, the Pan Degenerate Amplification and Adaptation (PANDAA) assay when screening for significant HIV-1 drug resistance mutations (DRMs) such as K65R, K103NS, M184VI, Y181C and G190A. Methods: we used previously generated amplicons from a cross-sectional study conducted between October 2018 and February 2020 of HIV-1 infected antiretroviral therapy (ART)-naïve or those reinitiating 1^st line ART (18 years or older). The performance of the PANDAA assay in screening K65R, K103NS, M184VI, Y181C, and G190A mutations compared to the reference assay, Sanger sequencing was evaluated by Cohen´s kappa coefficient on Stata version 14 (StataCorp LP, College Station, TX, USA).

Results

one hundred and twenty samples previously characterized by Sanger sequencing were assessed using PANDAA. PDR was found in 14% (17/120). PDR to non-nucleoside reverse transcriptase inhibitors (NNRTIs) was higher at 13% (16/120) than PDR to nucleotide reverse transcriptase inhibitors (NRTIs), 3% (3/120). The PANDAA assay showed a strong agreement with the reference assay, i.e. Sanger sequencing for all five target DRMs (kappa (95%CI); 0.93 (0.78-0.98)) and NNRTI DRMs (kappa (95%CI); 0.93 (0.77-0.980), and a perfect agreement for NRTI DRMs (kappa (95%CI); 1.00 (0.54-1.00)).

Conclusion

the PANDAA assay is a simple and rapid method to identify significant HIV DRMs in plasma samples as an alternative to Sanger sequencing in many RLS.

Diversity of HIV-1 subtypes and transmitted drug-resistance mutations among minority HIV-1 variants in a Turkish cohort

BACKGROUND

The World Health Organization (WHO) recommends the surveillance of transmitted drug resistance mutations (TDRMs) to ensure the effectiveness and sustainability of HIV treatment programs.

OBJECTIVE

Our aim was to determine the TDRMs and evaluate the distribution of HIV-1 subtypes using and compared next-generation sequencing (NGS) and Sanger-based sequencing (SBS) in a cohort of 44 antiretroviral treatment-naïve patients.

METHODS

All samples that were referred to the microbiology laboratory for HIV drug resistance analysis between December 2016 and February 2018 were included in the study. After exclusions, 44 treatment-naive adult patients with a viral load of >1000 copies/mL were analyzed. DNA sequencing for reverse transcriptase and protease regions was performed using both DeepChek ABL single round kit and Sanger-based ViroSeq HIV-1 Genotyping System. The mutations and HIV-1 subtypes were analyzed using the Stanford HIVdb version 8.6.1 Genotypic Resistance software, and TDRMs were assessed using the WHO surveillance drug-resistance mutation database. HIV-1 subtypes were confirmed by constructing a maximum-likelihood phylogenetic tree using Los Alamos IQ-Tree software.

RESULTS

NGS identified nucleos(t)ide reverse transcriptase inhibitor (NRTI)-TDRMs in 9.1% of the patients, non-nucleos(t)ide reverse transcriptase inhibitor (NNRTI)-TDRMs in 6.8% of the patients, and protease inhibitor (PI)-TDRMs in 18.2% of the patients at a detection threshold of ≥1%. Using SBS, 2.3% and 6.8% of the patients were found to have NRTI- and NNRTI-TDRMs, respectively, but no major PI mutations were detected. M41L, L74I, K65R, M184V, and M184I related to NRTI, K103N to NNRTI, and N83D, M46I, I84V, V82A, L24I, L90M, I54V to the PI sites were identified using NGS. Most mutations were found in low-abundance (frequency range: 1.0% - 4.7%) HIV-1 variants, except M41L and K103N. The subtypes of the isolates were found as follows; 61.4% subtype B, 18.2% subtype B/CRF02_AG recombinant, 13.6% subtype A, 4.5% CRF43_02G, and 2.3% CRF02_AG. All TDRMs, except K65R, were detected in HIV-1 subtype B isolates.

CONCLUSION

The high diversity of protease site TDRMs in the minority HIV-1 variants and prevalence of CRFs were remarkable in this study. All minority HIV-1 variants were missed by conventional sequencing. TDRM prevalence among minority variants appears to be decreasing over time at our center.

Next generation sequencing based in-house HIV genotyping method: validation report

Background

HIV genotyping has had a significant impact on the care and treatment of HIV/AIDS. At a clinical level, the test guides physicians on the choice of treatment regimens. At the surveillance level, it informs policy on consolidated treatment guidelines and microbial resistance control strategies. Until recently, the conventional test has utilized the Sanger sequencing (SS) method. Unlike Next Generation Sequencing (NGS), SS is limited by low data throughput and the inability of detecting low abundant drug-resistant variants. NGS can improve sensitivity and quantitatively identify low-abundance variants; in addition, it has the potential to improve efficiency as well as lowering costs when samples are batched. Despite the NGS benefits, its utilization in clinical drug resistance profiling is faced with mixed reactions. These are largely based on a lack of a consensus regarding the quality control strategy. Nonetheless, transitional views suggest validating the method against the gold-standard SS. Therefore, we present a validation report of an NGS-based in-house HIV genotyping method against the SS method in Uganda.

Results

Since there were no established proficiency test panels for NGS-based HIV genotyping, 15 clinical plasma samples for routine care were utilized. The use of clinical samples allowed for accuracy and precision studies. The workflow involved four main steps; viral RNA extraction, targeted amplicon generation, amplicon sequencing and data analysis. Accuracy of 98% with an average percentage error of 3% was reported for the NGS based assay against the SS platform demonstrating similar performance. The coefficient of variation (CV) findings for both the inter-run and inter-personnel precision showed no variability (CV ≤ 0%) at the relative abundance of ≥ 20%. For both inter-run and inter-personnel, a variation that affected the precision was observed at 1% frequency. Overall, for all the frequencies, CV registered a small range of (0–2%).

Conclusion

The NGS-based in-house HIV genotyping method fulfilled the minimum requirements that support its utilization for drug resistance profiling in a clinical setting of a low-income country. For more inclusive quality control studies, well-characterized wet panels need to be established.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12981-021-00390-8.

Development and Application of Performance Assessment Criteria for Next-Generation Sequencing-Based HIV Drug Resistance Assays

Next-generation sequencing (NGS)-based HIV drug resistance (HIVDR) assays outperform conventional Sanger sequencing in scalability, sensitivity, and quantitative detection of minority resistance variants. Thus far, HIVDR assays have been applied primarily in research but rarely in clinical settings. One main obstacle is the lack of standardized validation and performance evaluation systems that allow regulatory agencies to benchmark and accredit new assays for clinical use. By revisiting the existing principles for molecular assay validation, here we propose a new validation and performance evaluation system that helps to both qualitatively and quantitatively assess the performance of an NGS-based HIVDR assay. To accomplish this, we constructed a 70-specimen proficiency test panel that includes plasmid mixtures at known ratios, viral RNA from infectious clones, and anonymized clinical specimens. We developed assessment criteria and benchmarks for NGS-based HIVDR assays and used these to assess data from five separate MiSeq runs performed in two experienced HIVDR laboratories. This proposed platform may help to pave the way for the standardization of NGS HIVDR assay validation and performance evaluation strategies for accreditation and quality assurance purposes in both research and clinical settings.

The S68G polymorphism is a compensatory mutation associated with the drug resistance mutation K65R in CRF01_AE strains

BACKGROUND

The rate of S68G mutation in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase has increased and is closely related to the K65R mutation among CRF01_AE-infected patients who failed treatment. We aimed to explore the temporal association of S68G and K65R mutations and disclose the role of the former on susceptibility to nucleotide/nucleoside reverse transcriptase inhibitor (NRTI) and viral replication with the K65R double mutations among CRF01_AE-infected patients who failed treatment.

METHODS

The occurrence of S68G and K65R mutations was evaluated among HIV-1 of various subtypes in the global HIV Drug Resistance Database. The temporal association of S68G and K65R mutations was analyzed through next-generation sequencing in four CRF01_AE-infected patients who failed treatment with tenofovir/lamivudine/efavirenz. The impact of the S68G mutation on susceptibility to NRTI and replication fitness was analyzed using pseudovirus phenotypic resistance assays and growth competition assays, respectively.

RESULTS

The frequency of the S68G mutation increased by 1.4-9.7% in almost all HIV subtypes and circulating recombinant forms in treatment-experienced patients, except subtype F. The S68G mutation often occurred in conjunction with the K65R mutation among RTI-treated patients, with frequencies ranging 21.1-61.7% in various subtypes. Next-generation sequencing revealed that the S68G mutation occurred following the K65R mutation in three of the four CRF01_AE-infected patients. In these three patients, there was no significant change detected in the half maximal inhibitory concentration for zidovudine, tenofovir, or lamivudine between the K65R and K65R/S68G mutations, as demonstrated by the phenotypic resistance assays. Virus stocks of the K65R and K65R/S68G mutations were mixed with 4:6, 1:1, and 9:1 and cultured for 13 days, the K65R/S68G mutants outgrew those of the K65R mutants irrespective of the input ratio.

CONCLUSIONS

S68G may be a natural polymorphism and compensatory mutation of K65R selected by NRTIs in the CRF01_AE strain of HIV-1. This mutation does not affect susceptibility to NRTI; however, it improves the replication fitness of K65R mutants. This study deciphers the role of the S68G mutation in the HIV reverse transcriptase of the CRF01_AE strain and provides new evidence for the interpretation of drug-resistant mutations in non-B subtypes of HIV-1.

OLA-Simple: A software-guided HIV-1 drug resistance test for low-resource laboratories

Background

HIV drug resistance (HIVDR) testing can assist clinicians in selecting treatments. However, high complexity and cost of genotyping assays limit routine testing in settings where HIVDR prevalence has reached high levels.

Methods

The oligonucleotide ligation assay (OLA)-Simple kit was developed for detection of HIVDR against first-line non-nucleoside/nucleoside reverse transcriptase inhibitors and validated on 672 codons (168 specimens) from subtypes A, B, C, D, and AE. The kit uses dry reagents to facilitate assay setup, lateral flow devices for visual HIVDR detections, and in-house software with an interface for guiding users and analyzing results.

Findings

HIVDR analysis of specimens by OLA-Simple compared to Sanger sequencing revealed 99.6 ± 0.3% specificity and 98.2 ± 0.9% sensitivity, and compared to high-sensitivity assays, 99.6 ± 0.6% specificity and 86.2 ± 2.5% sensitivity, with 2.6 ± 0.9% indeterminate results. OLA-Simple was performed more rapidly compared to Sanger sequencing (<4 h vs. 35–72 h). Forty-one untrained volunteers blindly tested two specimens each with 96.8 ± 0.8% accuracy.

Interpretation

OLA-Simple compares favorably with HIVDR genotyping by Sanger and sensitive comparators. Instructional software enabled inexperienced, first-time users to perform the assay with high accuracy. The reduced complexity, cost, and training requirements of OLA-Simple could improve access to HIVDR testing in low-resource settings and potentially allow same-day selection of appropriate antiretroviral therapy.

Fund

USA National Institutes of Health R01; the Clinical and Retrovirology Research Core and the Molecular Profiling and Computational Biology Core of the UW CFAR; Seattle Children's Research Institute; UW Holloman Innovation Challenge Award; Pilcher Faculty Fellowship.

Validation of publicly-available software used in analyzing NGS data for HIV-1 drug resistance mutations and transmission networks in a Washington, DC, Cohort

The DC Cohort is an ongoing longitudinal observational study of persons living with HIV. To better understand HIV-1 drug resistance and potential transmission clusters among these participants, we performed targeted, paired-end next-generation sequencing (NGS) of protease, reverse transcriptase and integrase amplicons. We elected to use free, publicly-available software (HyDRA Web, Stanford HIVdb and HIV-TRACE) for data analyses so that laboratory personnel without extensive bioinformatics expertise could use it; making the approach accessible and affordable for labs worldwide. With more laboratories transitioning away from Sanger-based chemistries to NGS platforms, lower frequency drug resistance mutations (DRMs) can be detected, yet their clinical relevance is uncertain. We looked at the impact choice in cutoff percentage had on number of DRMs detected and found an inverse correlation between the two. Longitudinal studies will be needed to determine whether low frequency DRMs are an early indicator of emerging resistance. We successfully validated this pipeline against a commercial pipeline, and another free, publicly-available pipeline. RT DRM results from HyDRA Web were compared to both SmartGene and PASeq Web; using the Mantel test, R2 values were 0.9332 (p<0.0001) and 0.9097 (p<0.0001), respectively. PR and IN DRM results from HyDRA Web were then compared with PASeq Web only; using the Mantel test, R2 values were 0.9993 (p<0.0001) and 0.9765 (p<0.0001), respectively. Drug resistance was highest for the NRTI drug class and lowest for the PI drug class in this cohort. RT DRM interpretation reports from this pipeline were also highly correlative compared to SmartGene pipeline; using the Spearman's Correlation, rs value was 0.97757 (p<0.0001). HIV-TRACE was used to identify potential transmission clusters to better understand potential linkages among an urban cohort of persons living with HIV; more individuals were male, of black race, with an HIV risk factor of either MSM or High-risk Heterosexual. Common DRMs existed among individuals within a cluster. In summary, we validated a comprehensive, easy-to-use and affordable NGS approach for tracking HIV-1 drug resistance and identifying potential transmission clusters within the community.

Increased predominance of HIV-1 CRF01_AE and its recombinants in the Philippines

The growth rate of new HIV infections in the Philippines was the fastest of any countries in the Asia-Pacific region between 2010 and 2016. To date, HIV-1 subtyping results in the Philippines have been determined by characterizing only partial viral genome sequences. It is not known whether recombination occurs in the majority of unsequenced genome regions. Near-full-length genome (NFLG) sequences were obtained by amplifying two overlapping half genomes from plasma samples collected between 2015 and 2017 from 23 newly diagnosed infected individuals in the Philippines. Phylogenetic analysis showed that the newly characterized sequences were CRF01_AE (14), subtype B (3), CRF01/B recombinants (5) and a CRF01/CRF07/B recombinant (1). All 14 CRF01_AE formed a tight cluster, suggesting that they were derived from a single introduction. The time to the most recent common ancestor (tMRCA) for CRF01_AE in the Philippines was 1995 (1992-1998), about 10-15 years later than that of CRF01_AE in China and Thailand. All five CRF01/B recombinants showed distinct recombination patterns, suggesting ongoing recombination between the two predominant circulating viruses. The identification of partial CRF07_BC sequences in one CRF01/CRF07/B recombinant, not reported previously in the Philippines, indicated that CRF07_BC may have been recently introduced into that country from China, where CRF07_BC is prevalent. Our results show that the major epidemic strains may have shifted to an increased predominance of CRF01_AE and its recombinants, and that other genotypes such as CRF07_BC may have been introduced into the Philippines.

Characterization of minority HIV-1 drug resistant variants in the United Kingdom following the verification of a deep sequencing-based HIV-1 genotyping and tropism assay

BACKGROUND

The widespread global access to antiretroviral drugs has led to considerable reductions in morbidity and mortality but, unfortunately, the risk of virologic failure increases with the emergence, and potential transmission, of drug resistant viruses. Detecting and quantifying HIV-1 drug resistance has therefore become the standard of care when designing new antiretroviral regimens. The sensitivity of Sanger sequencing-based HIV-1 genotypic assays is limited by its inability to identify minority members of the quasispecies, i.e., it only detects variants present above ~ 20% of the viral population, thus, failing to detect minority variants below this threshold. It is clear that deep sequencing-based HIV-1 genotyping assays are an important step change towards accurately monitoring HIV-infected individuals.

METHODS

We implemented and verified a clinically validated HIV-1 genotyping assay based on deep sequencing (DEEPGEN™) in two clinical laboratories in the United Kingdom: St. George's University Hospitals Healthcare NHS Foundation Trust (London) and at NHS Lothian (Edinburgh), to characterize minority HIV-1 variants in 109 plasma samples from ART-naïve or -experienced individuals.

RESULTS

Although subtype B HIV-1 strains were highly prevalent (44%, 48/109), most individuals were infected with non-B subtype viruses (i.e., A1, A2, C, D, F1, G, CRF02_AG, and CRF01_AE). DEEPGEN™ was able to accurately detect drug resistance-associated mutations not identified using standard Sanger sequencing-based tests, which correlated significantly with patient's antiretroviral treatment histories. A higher proportion of minority PI-, NRTI-, and NNRTI-resistance mutations was detected in NHS Lothian patients compared to individuals from St. George's, mainly M46I/L and I50 V (associated with PIs), D67 N, K65R, L74I, M184 V/I, and K219Q (NRTIs), and L100I (NNRTIs). Interestingly, we observed an inverse correlation between intra-patient HIV-1 diversity and CD4⁺ T cell counts in the NHS Lothian patients.

CONCLUSIONS

This is the first study evaluating the transition, training, and implementation of DEEPGEN™ between three clinical laboratories in two different countries. More importantly, we were able to characterize the HIV-1 drug resistance profile (including minority variants), coreceptor tropism, subtyping, and intra-patient viral diversity in patients from the United Kingdom, providing a rigorous foundation for basing clinical decisions on highly sensitive and cost-effective deep sequencing-based HIV-1 genotyping assays in the country.

The dawn of precision medicine in HIV: state of the art of pharmacotherapy

INTRODUCTION

Combination antiretroviral therapy (ART) reduces viral load to under the limit of detection, successfully decreasing HIV-related morbidity and mortality. Due to viral mutations, complex drug combinations and different patient response, there is an increasing demand for individualized treatment options for patients.

AREAS COVERED

This review first summarizes the pharmacokinetic and pharmacodynamic profile of clinical first-line drugs, which serves as guidance for antiretroviral precision medicine. Factors which have influential effects on drug efficacy and thus precision medicine are discussed: patients' pharmacogenetic information, virus mutations, comorbidities, and immune recovery. Furthermore, strategies to improve the application of precision medicine are discussed.

EXPERT OPINION

Precision medicine for ART requires comprehensive information on the drug, virus, and clinical data from the patients. The clinically available genetic tests are a good starting point. To better apply precision medicine, deeper knowledge of drug concentrations, HIV reservoirs, and efficacy associated genes, such as polymorphisms of drug transporters and metabolizing enzymes, are required. With advanced computer-based prediction systems which integrate more comprehensive information on pharmacokinetics, pharmacodynamics, pharmacogenomics, and the clinically relevant information of the patients, precision medicine will lead to better treatment choices and improved disease outcomes.

Sanger and Next Generation Sequencing Approaches to Evaluate HIV-1 Virus in Blood Compartments

The implementation of antiretroviral treatment combined with the monitoring of drug resistance mutations improves the quality of life of HIV-1 positive patients. The drug resistance mutation patterns and viral genotypes are currently analyzed by DNA sequencing of the virus in the plasma of patients. However, the virus compartmentalizes, and different T cell subsets may harbor distinct viral subsets. In this study, we compared the patterns of HIV distribution in cell-free (blood plasma) and cell-associated viruses (peripheral blood mononuclear cells, PBMCs) derived from ART-treated patients by using Sanger sequencing- and Next-Generation sequencing-based HIV assay. CD4⁺CD45RA⁻RO⁺ memory T-cells were isolated from PBMCs using a BD FACSAria instrument. HIV pol (protease and reverse transcriptase) was RT-PCR or PCR amplified from the plasma and the T-cell subset, respectively. Sequences were obtained using Sanger sequencing and Next-Generation Sequencing (NGS). Sanger sequences were aligned and edited using RECall software (beta v3.03). The Stanford HIV database was used to evaluate drug resistance mutations. Illumina MiSeq platform and HyDRA Web were used to generate and analyze NGS data, respectively. Our results show a high correlation between Sanger sequencing and NGS results. However, some major and minor drug resistance mutations were only observed by NGS, albeit at different frequencies. Analysis of low-frequency drugs resistance mutations and virus distribution in the blood compartments may provide information to allow a more sustainable response to therapy and better disease management.

Clinical patterns associated with the concurrent detection of anti-HBs and HBV DNA

Simultaneous detection of anti-HBs and HBV DNA is a rare serological combination and has been described in acute and chronic HBV infection. To scrutinize viral and clinical patterns associated with concurrent detection of anti-HBs and HBV DNA. Simultaneous detection of anti-HBs and HBV DNA was observed in 64/1444 (4.4%) patients treated for HBV infection at the University Hospital of Essen from 2006 to 2016 (8 with acute, 20 with reactivated, and 36 chronic HBV infection). Clinical data and laboratory parameters were analyzed. Regions of the small hepatitis B surface antigen (SHB) and the reverse transcriptase (RT) were sequenced using next generation sequencing (NGS). Among the 64 patients with detectable HBV DNA and anti-HBs, 17 were HBsAg negative (HBsAg[-]), and two had acute liver failure. Patients with acute HBV infection had fewer genotype specific amino acid substitutions in the SHB region than patients with reactivated HBV infection (4 [4.5] vs 9 [16.25], P = 0.043). However, we could observe a significantly higher number of mutations in the a-determinant region when comparing chronically infected patients to patients with acute infection (0 [1] vs 1 [1], P = 0.044). The ratio of nonsynonymous to synonymous mutations (Ka/Ks) was on average >1 for the SHB region and <1 for the RT region. The Ka/Ks ratio (>1) in the SHB region indicates that anti-HBs might have exerted selection pressure on the HBsAg. In three cases the diagnosis of acute HBV infection would have been at least delayed by only focusing on HBsAg testing.

Comparison between next-generation and Sanger-based sequencing for the detection of transmitted drug-resistance mutations among recently infected HIV-1 patients in Israel, 2000-2014

INTRODUCTION

Transmitted drug-resistance mutations (TDRM) may hamper successful anti-HIV-1 therapy and impact future control of the HIV-1 epidemic. Recently infected, therapy-naïve individuals are best suited for surveillance of such TDRM. In this study, TDRM, detected by next-generation sequencing (NGS) were compared to those identified by Sanger-based population sequencing (SBS) in recently infected HIV-1 patients.

METHODS

Historical samples from 80 recently infected HIV-1 patients, diagnosed between 2000 and 2014, were analysed by MiSeq (NGS) and ABI (SBS). DeepChek-HIV (ABL) was used for interpretation of the results.

RESULTS

Most patients were males (80%); Men who have sex with men (MSM) was the major transmission group (58.8%). Overall, TDRM were detected in 31.3% of patients by NGS and 8.8% by SBS, with SBS TDRM restricted to persons infected with subtype B. All SBS-detected TDRM were identified by NGS. The prevalence of TDRM impacting protease inhibitors (PI), nucleoside reverse transcriptase inhibitors (NRTI) and non-nucleoside reverse transcriptase inhibitors (NNRTI) was 11.3, 26.2 7.5%, respectively, in NGS analyses and 0, 3.8 and 5%, respectively, in SBS analyses. More patients with NGS and SBS TDRM were identified in 2008-2014 (37.2% or 13.9%, respectively) compared to 2000-2007 (24.3% or 2.7%, respectively), and a significantly greater number of these patients had multiple NGS TDRM. The most abundant, albeit, minor-frequency RT TDRM, were the K65R and D67N, while K103N, M184V and T215S were high-frequency mutations. Minor TDRM did not become a major variant in later samples and did not hinder successful treatment.

CONCLUSIONS

NGS can replace SBS for mutation detection and allows for the detection of low-frequency TDRM not identified by SBS. Although rates of TDRM in Israel continued to increase from 2000 to 2014, minor TDRM did not become major species. The need for ongoing surveillance of low-frequency TDRM should be revisited in a larger study.

Recent advances in understanding HIV evolution

The human immunodeficiency virus (HIV) evolves rapidly owing to the combined activity of error-prone reverse transcriptase, recombination, and short generation times, leading to extensive viral diversity both within and between hosts. This diversity is a major contributing factor in the failure of the immune system to eradicate the virus and has important implications for the development of suitable drugs and vaccines to combat infection. This review will discuss the recent technological advances that have shed light on HIV evolution and will summarise emerging concepts in this field.

Diagnostic virology and patient care: from vaguely interesting to vitally important

The existence of pathogenic viruses was inferred by experiments at the turn of the twentieth century. Key developments in detection of viruses, including electron microscopy and monolayer cell culture, were made in the middle of that century. However, in terms of patient care, the results from the virology laboratory often arrived the patient was 'better or dead'. The advent of molecular techniques, particularly polymerase chain reaction and more recently whole genome sequencing made timely and accurate diagnosis of viral infections feasible. A range of approaches have been taken to identify and characterise new viruses. Vaccines against viruses have made it possible to eliminate two pathogenic mammalian viruses altogether, with several others close to eradication. The role of biomedical scientists working in diagnostic virology is more relevant to patient care than ever.

An Efficient Microarray-Based Genotyping Platform for the Identification of Drug-Resistance Mutations in Majority and Minority Subpopulations of HIV-1 Quasispecies

The response of human immunodeficiency virus type 1 (HIV-1) quasispecies to antiretroviral therapy is influenced by the ensemble of mutants that composes the evolving population. Low-abundance subpopulations within HIV-1 quasispecies may determine the viral response to the administered drug combinations. However, routine sequencing assays available to clinical laboratories do not recognize HIV-1 minority variants representing less than 25% of the population. Although several alternative and more sensitive genotyping techniques have been developed, including next-generation sequencing (NGS) methods, they are usually very time consuming, expensive and require highly trained personnel, thus becoming unrealistic approaches in daily clinical practice. Here we describe the development and testing of a HIV-1 genotyping DNA microarray that detects and quantifies, in majority and minority viral subpopulations, relevant mutations and amino acid insertions in 42 codons of the pol gene associated with drug- and multidrug-resistance to protease (PR) and reverse transcriptase (RT) inhibitors. A customized bioinformatics protocol has been implemented to analyze the microarray hybridization data by including a new normalization procedure and a stepwise filtering algorithm, which resulted in the highly accurate (96.33%) detection of positive/negative signals. This microarray has been tested with 57 subtype B HIV-1 clinical samples extracted from multi-treated patients, showing an overall identification of 95.53% and 89.24% of the queried PR and RT codons, respectively, and enough sensitivity to detect minority subpopulations representing as low as 5–10% of the total quasispecies. The developed genotyping platform represents an efficient diagnostic and prognostic tool useful to personalize antiviral treatments in clinical practice.

Low-Frequency Drug Resistance in HIV-Infected Ugandans on Antiretroviral Treatment Is Associated with Regimen Failure

Most patients failing antiretroviral treatment in Uganda continue to fail their treatment regimen even if a dominant drug-resistant HIV-1 genotype is not detected. In a recent retrospective study, we observed that approximately 30% of HIV-infected individuals in the Joint Clinical Research Centre (Kampala, Uganda) experienced virologic failure with a susceptible HIV-1 genotype based on standard Sanger sequencing. Selection of minority drug-resistant HIV-1 variants (not detectable by Sanger sequencing) under antiretroviral therapy pressure can lead to a shift in the viral quasispecies distribution, becoming dominant members of the virus population and eventually causing treatment failure. Here, we used a novel HIV-1 genotyping assay based on deep sequencing (DeepGen) to quantify low-level drug-resistant HIV-1 variants in 33 patients failing a first-line antiretroviral treatment regimen in the absence of drug-resistant mutations, as screened by standard population-based Sanger sequencing. Using this sensitive assay, we observed that 64% (21/33) of these individuals had low-frequency (or minority) drug-resistant variants in the intrapatient HIV-1 population, which correlated with treatment failure. Moreover, the presence of these minority HIV-1 variants was associated with higher intrapatient HIV-1 diversity, suggesting a dynamic selection or fading of drug-resistant HIV-1 variants from the viral quasispecies in the presence or absence of drug pressure, respectively. This study identified low-frequency HIV drug resistance mutations by deep sequencing in Ugandan patients failing antiretroviral treatment but lacking dominant drug resistance mutations as determined by Sanger sequencing methods. We showed that these low-abundance drug-resistant viruses could have significant consequences for clinical outcomes, especially if treatment is not modified based on a susceptible HIV-1 genotype by Sanger sequencing. Therefore, we propose to make clinical decisions using more sensitive methods to detect minority HIV-1 variants.

A Pan-HIV Strategy for Complete Genome Sequencing

Molecular surveillance is essential to monitor HIV diversity and track emerging strains. We have developed a universal library preparation method (HIV-SMART [i.e.,switchingmechanismat 5' end ofRNAtranscript]) for next-generation sequencing that harnesses the specificity of HIV-directed priming to enable full genome characterization of all HIV-1 groups (M, N, O, and P) and HIV-2. Broad application of the HIV-SMART approach was demonstrated using a panel of diverse cell-cultured virus isolates. HIV-1 non-subtype B-infected clinical specimens from Cameroon were then used to optimize the protocol to sequence directly from plasma. When multiplexing 8 or more libraries per MiSeq run, full genome coverage at a median ∼2,000× depth was routinely obtained for either sample type. The method reproducibly generated the same consensus sequence, consistently identified viral sequence heterogeneity present in specimens, and at viral loads of ≤4.5 log copies/ml yielded sufficient coverage to permit strain classification. HIV-SMART provides an unparalleled opportunity to identify diverse HIV strains in patient specimens and to determine phylogenetic classification based on the entire viral genome. Easily adapted to sequence any RNA virus, this technology illustrates the utility of next-generation sequencing (NGS) for viral characterization and surveillance.

Next-Generation Sequencing for Infectious Disease Diagnosis and Management: A Report of the Association for Molecular Pathology

Next-generation sequencing (NGS) technologies are increasingly being used for diagnosis and monitoring of infectious diseases. Herein, we review the application of NGS in clinical microbiology, focusing on genotypic resistance testing, direct detection of unknown disease-associated pathogens in clinical specimens, investigation of microbial population diversity in the human host, and strain typing. We have organized the review into three main sections: i) applications in clinical virology, ii) applications in clinical bacteriology, mycobacteriology, and mycology, and iii) validation, quality control, and maintenance of proficiency. Although NGS holds enormous promise for clinical infectious disease testing, many challenges remain, including automation, standardizing technical protocols and bioinformatics pipelines, improving reference databases, establishing proficiency testing and quality control measures, and reducing cost and turnaround time, all of which would be necessary for widespread adoption of NGS in clinical microbiology laboratories.

Single Genome Analysis for the Detection of Linked Multiclass Drug Resistance Mutations in HIV-1-Infected Children After Failure of Protease Inhibitor-Based First-Line Therapy

The WHO recommends protease inhibitor (PI)-based antiretroviral therapy (ART) for vertically infected children after failed nevirapine (NVP) prophylaxis. Emergence of PI resistance on the backdrop of preexisting non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance could compromise long-term treatment options in such children. We characterized multiclass drug resistance using single genome sequencing (SGS) in children with viremia while receiving PI-based ART. We applied SGS of HIV-1 protease (PR) and reverse transcriptase to longitudinal samples from a cohort of the Children with HIV Early Antiretroviral Therapy trial with viral loads >1000 copies per milliliter after 40 weeks of early ART. Bulk sequencing revealed NVP-selected resistance in 50% of these children, whereas SGS revealed NVP-selected resistance in 70%. Two children had baseline NRTI and PI mutations, suggesting previous maternal ART. Linked multiclass drug resistance after PI-based ART was detected by SGS in 2 of 10 children. In one child, the majority species contained M184V in reverse transcriptase linked to L10F, M46I/L, I54V, and V82A in PR and a triple-class drug-resistant variant with these mutations linked to the NNRTI mutation V108I. In the second child, the majority species contained M184V and V82A linked within viral genomes. We conclude that when PI-based ART is initiated soon after birth after single dose-NVP prophylaxis, PI and NRTI resistance can occur in the majority species as expected and also be selected on the same genomes as preexisting NNRTI-resistant mutations. These observations highlight a future therapeutic challenge for vertically infected children where antiretroviral drug classes are limited.

Identification of variants in primary and recurrent glioblastoma using a cancer-specific gene panel and whole exome sequencing

Glioblastoma (GBM) is an aggressive, malignant brain tumor typically resulting in death of the patient within one year following diagnosis; and those who survive beyond this point usually present with tumor recurrence within two years (5-year survival is 5%). The genetic heterogeneity of GBM has made the molecular characterization of these tumors an area of great interest and has led to identification of molecular subtypes in GBM. The availability of sequencing platforms that are both fast and economical can further the adoption of tumor sequencing in the clinical environment, potentially leading to identification of clinically actionable genetic targets. In this pilot study, comprised of triplet samples of normal blood, primary tumor, and recurrent tumor samples from three patients; we compared the ability of Illumina whole exome sequencing (ExomeSeq) and the Ion AmpliSeq Comprehensive Cancer Panel (CCP) to identify somatic variants in patient-paired primary and recurrent tumor samples. Thirteen genes were found to harbor variants, the majority of which were exclusive to the ExomeSeq data. Surprisingly, only two variants were identified by both platforms and they were located within the PTCH1 and NF1 genes. Although preliminary in nature, this work highlights major differences in variant identification in data generated from the two platforms. Additional studies with larger samples sizes are needed to further explore the differences between these technologies and to enhance our understanding of the clinical utility of panel based platforms in genomic profiling of brain tumors.

Deep sequencing: becoming a critical tool in clinical virology

Population (Sanger) sequencing has been the standard method in basic and clinical DNA sequencing for almost 40 years; however, next-generation (deep) sequencing methodologies are now revolutionizing the field of genomics, and clinical virology is no exception. Deep sequencing is highly efficient, producing an enormous amount of information at low cost in a relatively short period of time. High-throughput sequencing techniques have enabled significant contributions to multiples areas in virology, including virus discovery and metagenomics (viromes), molecular epidemiology, pathogenesis, and studies of how viruses to escape the host immune system and antiviral pressures. In addition, new and more affordable deep sequencing-based assays are now being implemented in clinical laboratories. Here, we review the use of the current deep sequencing platforms in virology, focusing on three of the most studied viruses: human immunodeficiency virus (HIV), hepatitis C virus (HCV), and influenza virus.