Primary Drug Resistance Research Articles

Virological efficacy with first-line antiretroviral treatment in India: predictors of viral failure and evidence of viral resuppression.

Combination antiretroviral therapy (ART) has improved in efficacy, durability and tolerability. Virological efficacy studies in India are limited. We determined incidence and predictors of virological failure among patients initiating first-line ART and described virological resuppression after confirmed failure, with the goal of informing national policy. Therapy-naïve patients initiated on first-line ART as per national guidelines were monitored every 3months for adherence and virological response over 2years. Genotyping on baseline samples was performed to assess primary drug resistance. Multivariate Cox regression analysis was used to assess predictors of virological failure. Virological failure rate among 599 eligible patients was 10.7 failures per 100 person-years. Cumulative failure incidence was 13.2% in the first year and 16.5% over 2years. Patients initiated on tenofovir had a significantly lower rate of virological failure than those on stavudine or zidovudine (6.7 vs. 11.9 failures per 100 person-years, P=0.013). Virological failure was independently associated with age <40years, mean adherence <95%, non-tenofovir-containing regimens and presence of primary drug resistance. In a subset of 311 patients who were reassessed after treatment failure, 19% (11/58) patients resuppressed their viral load to <400 copies/ml after confirmed virological failure. Our results support the inclusion of tenofovir as first-line ART in resource-limited settings and a role for regular adherence counselling and virological monitoring for enhanced treatment success. Detection of early virological failure should provide an opportunity to augment adherence counselling and repeat viral load testing before therapy switch is considered.

Booster effect to neonatal hepatitis B vaccinees at age 10−14 years on hepatitis B virus infection in adulthood

treatment-naive HIV/HCV coinfected patients in China across a broad spectrum of HCV genotypes. Methods: Population-basedNS3/4A sequencingwas completed for 826 HIV/HCV coinfected patients enrolled between 2004 and 2013, from 12 provinces across China. All patients were naive to antiretroviral treatment for HIV and any prior or investigational treatment for HCV. In-house primers for genotypes 1–6were used. NS3 sequences were aligned against reference sequences and mutations were manually identified in the following positions reported to confer resistance to HCV protease inhibitors: 36, 41, 43, 54, 55, 80, 109, 122, 132, 155, 156, 168, and 170. Findings: Overall, 81% (632/778) of all HCV sequences had at least one mutation associated with resistance to HCV protease inhibitors. Mutations were found in 4% (1/28) of genotype 1a, 44% (73/165) of genotype 1b, 100% (23/23) of genotype 2a, 100% (125/125) of genotype 3a, 100% (112/112) of genotype 3b, 99% (299/303) of genotype 6a, and none (0/22) of genotype 6n/u/v sequences. The Q80K mutation was present in 98% of genotype 6a sequences. Mutations with the potential to cause high-level decreased drug susceptibility are rare, occurring in only 0.8% of patients. Interpretation: The low frequency of high-level mutations associated with primary protease inhibitor drug resistance among most genotypes is encouraging, but the presence of theQ80Kmutation among patients with HCV genotype 6a is concerning given the association with decreased simeprevir efficacy in genotype 1a. Further phenotypic studies and clinical research are needed.

Current Nanotechnological Approaches for an Effective Delivery of Bioactive Drug Molecules to Overcome Drug Resistance Tuberculosis.

Tuberculosis (TB) is an airborne communicable disease, mainly caused by aerobic, non-motile, rodshaped, weakly gram-positive, acid-fast tubercular bacillus Mycobacterium tuberculosis (MTb). Mycobacterium has worsened the problem in humans by acquiring various types of resistances like Multi-drug resistance (MDR), Single-drug resistance (SDR), and Extensive drug resistance (XDR). Some clinical problems and challenges associated with conventional TB chemotherapy include poor patient compliance, longer duration of chemotherapy, lesser cell permeability, primary drug resistance, difficulty in maintaining higher drug concentrations at the infected site, and degradation of the drug before reaching the target site. Thus, newer micrometric or nanometric carriers drug delivery approaches are needed. Colloidal (vesicular and particulate) drug carriers offer numerous advantages over conventional therapy such as better systemic bioavailability, rapid onset of therapeutic action, avoidance of first-pass metabolism, providing sustained and controlled release, fewer dosing frequencies, desired pharmacokinetic prole and route of administration. This review article present updates and fabrication of drug delivery approaches for tuberculosis chemotherapy in order to improve patient compliance.

Targeting melanoma with NT157 by blocking Stat3 and IGF1R signaling.

It is well known that specific signal transduction inhibitors rarely suffice as anti-cancer agents. In most cases, tumors possess primary drug resistance due to their inherent heterogeneity, or acquire drug resistance due to genomic instability and acquisition of mutations. Here we expand our previous study of the novel compound, NT157, and show that it acts as a dual-targeting agent that invokes the blockage of two signal transduction pathways that are central to the development and maintenance of multiple human cancers. We show that NT157 targets not only IGF1R-IRS1/2, as previously reported, but also the Stat3 signaling pathway and demonstrates remarkable anti-cancer characteristics in A375 human melanoma cells and in a metastatic melanoma model in mice.

Decreased functional activity of multidrug resistance protein in primary colorectal cancer.

BackgroundThe ATP-Binding Cassette (ABC)-transporter MultiDrug Resistance Protein 1 (MDR1) and Multidrug Resistance Related Protein 1 (MRP1) are expressed on the surface of enterocytes, which has led to the belief that these high capacity transporters are responsible for modulating chemosensitvity of colorectal cancer. Several immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR) studies have provided controversial results in regards to the expression levels of these two ABC-transporters in colorectal cancer. Our study was designed to determine the yet uninvestigated functional activity of MDR1 and MRP1 transporters in normal human enterocytes compared to colorectal cancer cells from surgical biopsies.Methods100 colorectal cancer and 28 adjacent healthy mucosa samples were obtained by intraoperative surgical sampling. Activity of MDR1 and MRP1 of viable epithelial and cancer cells were determined separately with the modified calcein-assay for multidrug resistance activity and sufficient data of 73 cancer and 11 healthy mucosa was analyzed statistically.ResultsSignificantly decreased mean MDR1 activity was found in primary colorectal cancer samples compared to normal mucosa, while mean MRP1 activity showed no significant change. Functional activity was not affected by gender, age, stage or grade and localization of the tumor.ConclusionWe found lower MDR activity in cancer cells versus adjacent, apparently, healthy control tissue, thus, contrary to general belief, MDR activity seems not to play a major role in primary drug resistance, but might rather explain preferential/selective activity of Irinotecan and/or Oxaliplatin. Still, this picture might be more complex since chemotherapy by itself might alter MDR activity, and furthermore, today limited data is available about MDR activity of cancer stem cells in colorectal cancers.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1675739129145824

Meta-analysis and time series modeling allow a systematic review of primary HIV-1 drug-resistant prevalence in Latin America and Caribbean.

Here we review the prevalence of HIV-1 primary drug resistance in Latin America and Caribbean using meta-analysis as well as time-series modeling. We also discuss whether there could be a drawback to HIV/AIDS programs due to drug resistance in Latin America and Caribbean in the next years. We observed that, although some studies report low or moderate primary drug resistance prevalence in Caribbean countries, this evidence needs to be updated. In other countries, such as Brazil and Argentina, the prevalence of drug resistance appears to be rising. Mutations conferring resistance against reverse transcriptase inhibitors were the most frequent in the analyzed populations (70% of all mutational events). HIV-1 subtype B was the most prevalent in Latin America and the Caribbean, although subtype C and B/F recombinants have significant contributions in Argentina and Brazil. Thus, we suggest that primary drug resistance in Latin America and the Caribbean could have been underestimated. Clinical monitoring should be improved to offer better therapy, reducing the risk for HIV-1 resistance emergence and spread, principally in vulnerable populations, such as men who have sex with men transmission group, sex workers and intravenous drug users.

Su1147 The Marked Increase of Primary and Secondary Drug Resistance in Helicobacter pylori Necessitates the Establishment of More Reliable Eradication Protocols in Japan

Su1147 The Marked Increase of Primary and Secondary Drug Resistance in Helicobacter pylori Necessitates the Establishment of More Reliable Eradication Protocols in Japan

HIF1α Regulates mTOR Signaling and Viability of Prostate Cancer Stem Cells.

Tumor-initiating subpopulations of cancer cells, also known as cancer stem cells (CSC), were recently identified and characterized in prostate cancer. A well-characterized murine model of prostate cancer was used to investigate the regulation of hypoxia-inducible factor 1α (HIF1A/HIF1α) in CSCs and a basal stem cell subpopulation (Lin(-)/Sca-1(+)/CD49f(+)) was identified, in primary prostate tumors of mice, with elevated HIF1α expression. To further analyze the consequences of hypoxic upregulation on stem cell proliferation and HIF1α signaling, CSC subpopulations from murine TRAMP-C1 cells (Sca-1(+)/CD49f(+)) as well as from a human prostate cancer cell line (CD44(+)/CD49f(+)) were isolated and characterized. HIF1α levels and HIF target gene expression were elevated in hypoxic CSC-like cells, and upregulation of AKT occurred through a mechanism involving an mTOR/S6K/IRS-1 feedback loop. Interestingly, resistance of prostate CSCs to selective mTOR inhibitors was observed because of HIF1α upregulation. Thus, prostate CSCs show a hypoxic deactivation of a feedback inhibition of AKT signaling through IRS-1. In light of these results, we propose that deregulation of the PI3K/AKT/mTOR pathway through HIF1α is critical for CSC quiescence and maintenance by attenuating CSC metabolism and growth via mTOR and promoting survival by AKT signaling. We also propose that prostate CSCs can exhibit primary drug resistance to selective mTOR inhibitors. This work contributes to a deeper understanding of hypoxic regulatory mechanisms in CSCs and will help devise novel therapies against prostate cancer.

Primary drug resistance in a region with high burden of tuberculosis. A critical problem.

To determine rates of drug resistance in new cases of pulmonary tuberculosis in a region with a high burden of the disease. New case suspects were referred for drug susceptibility testing. 28.9% of new cases were resistant to at least one first line drug; 3.9% had a multidrug-resistant strain, 15.6% a monoresistant strain and 9.4% a polyresistant strain. Our rate of drug resistant tuberculosis in new cases is very high; this has important clinical implications, since even monoresistance can have a negative impact on the outcome of new cases treated empirically with a six month regimen.

Limited increase in primary HIV-1C drug resistance mutations in treatment naïve individuals in Ethiopia.

Antiretroviral drug resistance is a major challenge for management and control of HIV-1 infection worldwide and particularly in resource limited countries. The frequency of primary drug resistance mutations (DRMs) and of naturally occurring polymorphisms was determined in 83 antiretroviral treatment (ART) naïve Ethiopian individuals infected with HIV-1, consecutively enrolled in 2010. In all individuals HIV-1C was found. The median (interquartile range) of CD4(+) T-cell count and viral load were 100 (49-201) cells/μl and 44,640 (12,553-134,664) copies/ml, respectively. Protease (PR) and reverse transcriptase (RT) genes of HIV-1 RNA were amplified and sequenced. The proportion of primary DRM to any drug class, using the World Health Organization mutation lists, was 7.2% (6/83), thus exceeding the WHO threshold limit of 5%. Three individuals (3.6%) had non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations, two individuals (2.4%) had protease inhibitor mutations, and one (1.2%) had mutations associated with two drug classes (nucleoside reverse transcriptase inhibitor and NNRTI). In addition, the frequency of polymorphisms in the PR and RT genes was higher compared with previous studies in Ethiopian as well as worldwide isolates. Hence, genotypic drug resistance testing as part of routine management of individuals seems reasonable even in resource limited countries prior to treatment in order to allow proper choice of ART.

Pattern of primary tuberculosis drug resistance and associated treatment outcomes in Transnistria, Moldova

Pattern of primary tuberculosis drug resistance and associated treatment outcomes in Transnistria, Moldova

Evaluation of melanoma antigen gene A3 expression in drug resistance of epidermal growth factor receptor-tyrosine kinase inhibitors in advanced nonsmall cell lung cancer treatment.

To investigate the correlation between melanoma antigen gene A3 (MAGE-A3) expression and progression-free survival (PFS) of nonsmall cell lung cancer (NSCLC) patients with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKIs) therapy, aiming to provide a basis for research and treatment of EGFR-TKIs resistance. Retrospective analysis is conducted of PFS of 359 NSCLC patients who have been tested positive for EGFR, and experienced drug resistance during oral treatment of icotinib. MAGE-A3 expression is tested using immunology and histology chemistry methods, and T790M and c-MeT expression are tested using mutation-enriched polymerase chain reaction. (1) MAGE-A3 expression in targeted treatment of NSCLC patients shows a positive rate of 33.98%. The comparative difference between MAGE-A3 expression and T790M, c-MeT and other resistance genes was not statistically significant (P > 0.05). (2) MAGE-A3 expression was higher in patients with NSCLC targeted therapy of primary drug resistance of positive rate than acquired resistance; meanwhile the expression level differences in three modes of acquired resistance are statistically significant (P < 0.05). (3) PFS of MAGE-A3 positive expression in the targeted treatment of acquired drug resistance in patients with NSCLC is shorter than the PFS of MAGE-A3 negative expression (P = 0.01); the comparative PFS differences in the three kinds of acquired drug resistance pattern have statistical significance (P = 0.02). (4) PFS and levels of MAGE-A3 expression in NSCLC patients with the three modes of acquired resistance are negatively correlated (P < 0.01), and MAGE-A3 expression has no correlation with age, gender, pathological type or PS score (P > 0.05). MAGE-A3 expression in EGFR-TKIs target therapy in NSCLC patient suggests that there might be EGFR-TKIs drug resistance, and the higher the level of expression, the shorter the time of acquired drug resistance.

The SH2 Domain of BCR-ABL1 Regulates Kinase Autophosphorylation By Controlling Activation Loop Accessibility

Chronic myelogenous leukemia (CML) is caused by BCR-ABL1, which is a constitutively active form of the Abelson tyrosine kinase (ABL1). While treatment with the tyrosine kinase inhibitors imatinib, nilotinib, dasatinib, bosutinib or ponatinib that target the ATP binding pocket of BCR-ABL1 leads to durable cytogenetic and molecular remissions in the majority CML patients, primary and secondary drug resistance remains a clinical problem. Targeting additional sites in the BCR-ABL1 kinase outside the highly conserved ATP binding pocket may be an alternative strategy to restrict drug resistance and limit side effects of ATP-competitive drugs with low selectivity. Our recent work has shown that an allosteric intramolecular interaction of the BCR-ABL1 SH2 domain with its kinase domain is critical for leukemogenesis and can be targeted with an engineered high-affinity binding protein.We have now elucidated the molecular mechanisms responsible for the regulation of BCR-ABL1 kinase activity by its SH2 domain: To this end, we set-up an efficient expression system for the BCR-ABL1 SH2-kinase domain unit in E.coli with excellent yield, purity and activity. Detailed biophysical and biochemical analysis of the purified recombinant proteins in vitro recapitulated SH2-dependent regulation of BCR-ABL1 in CML cells and enabled a quantitative enzymatic analysis of BCR-ABL1 activation. Unexpectedly, we found that the interaction of the SH2 domain with the kinase domain is the critical switch that shifts the BCR-ABL1 activation loop from an otherwise closed to a fully open conformation and enables its autophosphorylation. The activation loop is a central and almost universally used control element that regulates the activity of protein kinases, as the conformation and phosphorylation status of the activation loop determines substrate binding to the active site. In BCR-ABL1, activation loop phosphorylation is required for transformation of fibroblasts and haematopoietic progenitors. We show that the SH2-kinase interaction enables autophosphorylation of the activation loop in trans by rendering a key phosphorylation site (Tyr-412) highly accessible. This requires prior phosphorylation of Tyr-245 in the SH2-kinase linker of BCR-ABL1. Mutational disruption of the SH2-kinase interaction abolished activation loop phosphorylation. Importantly, this effect was independent of the phosphotyrosine binding ability of the SH2 domain, which indicated that the SH2 domain is a true allosteric activator of BCR-ABL1 kinase activity. We also show that the spectrum of tyrosine phosphorylation sites that we mapped by mass spectrometry in vitro were vastly overlapping with the observed BCR-ABL1 phosphorylation sites in CML cells indicating that BCR-ABL1 autophosphorylation might be the major mechanism that determines its cellular phosphorylation status.In summary, our study demonstrates a novel mechanism by which a protein-protein interaction domain may allosterically mediate the transition of an inactive to an active kinase conformation in a key oncoprotein. This work may serve as an archetype to identify further allosteric regulatory mechanisms in other tyrosine kinases that are activated in haematological malignancies and facilitate the development of new allosteric inhibitors targeting oncogenic tyrosine kinases. DisclosuresNo relevant conflicts of interest to declare.

Mafb Protein Confers Primary Resistance of Myeloma to Proteasome Inhibitors

Multiple myeloma (MM) is a malignancy of terminally differentiated clonal plasma cells displaying significant molecular heterogeneity with 7 subgroups defined by gene expression profiling (GEP). Our previous work showed that both the MS and MF subgroups associated with inferior survival (Zhan et al, Blood 2006). Furthermore, clinical studies have demonstrated that the addition of the proteasome inhibitor (PI) bortezomib (Bzb) to high dose melphalan based regimens provided a major advantage to patients in MS subgroup while patients in the MF subgroups (including C-MAF and MAFb) did not benefit from Bzb (Nair, Blood 2010). We have previously demonstrated that Bzb prevents c-MAF protein degradation leading to primary drug resistance (Abstract # 281, ASH 2013). In the present study, we assessed the ability of MAFb, another MAF family member, to influence the innate resistance to proteasome inhibitors (PI) and identify the molecular mechanism underlying the resistance of proteasome inhibitors in high MAFb-expressing patients.To investigate the association of the limited therapeutic effect of proteasome inhibitors in the different molecular subgroup of myeloma, we compared the IC50 of Bzb and carfilzomib (CFZ) in 29 myeloma cell lines (MMCL) belonging to different GEP-based molecular subgroups. IC50 concentrations of Bzb were higher (>25 nM) in all 4 MAFb MMCL and >60 nM in one MAFb MMCL, which expressed the highest level of MAFb protein, as determined by immunoblot analysis. In contrast, Bzb IC50 levels were lower (7.5-20 nM) for the MMCL belonging to the other molecular subgroups. For CFZ, IC50 concentrations were higher (>30nM) in all 11 c-MAF cell lines, while the IC50 levels were lower (2-20 nM) for the MMCL belonging to other molecular subgroup. One MMCL harboring t (14; 20) with high IC50 of Bzb (35 nM) showed low IC50 (10 nM) for CFZ. These results indicate that high MAFb expression in myeloma cells may contribute to primary resistance to Bzb and MM cells that express high MAFb protein although resistant to Bzb are sensitive to CFZ. Mechanistically, immunoblotting analysis demonstrated that exposure to Bzb resulted in increased MAFb protein levels in a dose-dependent manner, suggesting that Bzb prevents the degradation of MAFb protein in myeloma cells.To further confirm that drug-induced stabilization of MAFb protein confers resistance to Bzb and partially to CFZ, we generated loss of functional MAFb cells by silencing MAFb expression in a t (14;20) positive myeloma cell line using lentiviral shRNA specific to MAFb mRNA (shMAFb). shMAFb infected myeloma cells had 85% lower levels of MAFb mRNA and protein level compared with the cells infected with scrambled shRNA. Additionally, significantly decreased ITGB (9.1 fold), E-cadherin (2.5-fold), CCND2 (5.5-fold), and CCR1 (25-fold) levels were observed in these cells, compared with the cells infected with control viral vector. Silencing MAFb expression significantly decreased proliferation of myeloma cells (65.1% decrease, p=2.1E-6). Moreover, Bzb treatment of the cells infected with shMAFb led to 50.2%, inhibition (P=2.9E-8) of proliferation compared with control cells. Similarly, CFZ treatment of cells with silenced MAFb resulted in 54.3% (P=3.5E-8) inhibition of proliferation compared with control cells. Taken together, our results indicate that high expression of MAFb protein, similar to c-MAF, confers primary resistance to Bzb as well as to CFZ. In addition Bzb induces stabilization of MAFb protein, further increasing resistance to Bzb. These data provide the molecular rational for adopting an alternative therapeutic strategy for high-MAFb expressing myeloma patients. DisclosuresMorgan:Celgene Corp: Membership on an entity’s Board of Directors or advisory committees; Novartis: Membership on an entity’s Board of Directors or advisory committees; Janssen: Membership on an entity’s Board of Directors or advisory committees; Myeloma UK: Membership on an entity’s Board of Directors or advisory committees; International Myeloma Foundation: Membership on an entity’s Board of Directors or advisory committees; The Binding Site: Membership on an entity’s Board of Directors or advisory committees; MMRF: Membership on an entity’s Board of Directors or advisory committees.

HIV-1 diversity, transmission dynamics and primary drug resistance in Angola.

ObjectivesTo assess HIV-1 diversity, transmission dynamics and prevalence of transmitted drug resistance (TDR) in Angola, five years after ART scale-up.MethodsPopulation sequencing of the pol gene was performed on 139 plasma samples collected in 2009 from drug-naive HIV-1 infected individuals living in Luanda. HIV-1 subtypes were determined using phylogenetic analysis. Drug resistance mutations were identified using the Calibrated Population Resistance Tool (CPR). Transmission networks were determined using phylogenetic analysis of all Angolan sequences present in the databases. Evolutionary trends were determined by comparison with a similar survey performed in 2001.Results47.1% of the viruses were pure subtypes (all except B), 47.1% were recombinants and 5.8% were untypable. The prevalence of subtype A decreased significantly from 2001 to 2009 (40.0% to 10.8%, P = 0.0019) while the prevalence of unique recombinant forms (URFs) increased>2-fold (40.0% to 83.1%, P<0.0001). The most frequent URFs comprised untypable sequences with subtypes H (U/H, n = 7, 10.8%), A (U/A, n = 6, 9.2%) and G (G/U, n = 4, 6.2%). Newly identified U/H recombinants formed a highly supported monophyletic cluster suggesting a local and common origin. TDR mutation K103N was found in one (0.7%) patient (1.6% in 2001). Out of the 364 sequences sampled for transmission network analysis, 130 (35.7%) were part of a transmission network. Forty eight transmission clusters were identified; the majority (56.3%) comprised sequences sampled in 2008–2010 in Luanda which is consistent with a locally fuelled epidemic. Very low genetic distance was found in 27 transmission pairs sampled in the same year, suggesting recent transmission events.ConclusionsTransmission of drug resistant strains was still negligible in Luanda in 2009, five years after the scale-up of ART. The dominance of small and recent transmission clusters and the emergence of new URFs are consistent with a rising HIV-1 epidemics mainly driven by heterosexual transmission.

1176Analysis of the Primary Antiretroviral Drug Resistance among HIV-1 Naý¨ve Patients in a Tertiary Hospital in Saudi Arabia

1176Analysis of the Primary Antiretroviral Drug Resistance among HIV-1 Naý¨ve Patients in a Tertiary Hospital in Saudi Arabia

The development of drug resistance mutations K103N Y181C and G190A in long term Nevirapine-containing antiviral therapy.

ObjectiveWe built a cohort study of HIV patients taking long-term first-line Antiretroviral Therapy in 2003. In this assay, we focused on the development of primary drug resistance mutations against Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI), K103N, Y181C and G190A.MethodThe cohort study was built in Henan province, China. We used Single Genome Amplification (SGA) to analyze the frequency of K103N, Y181C and G190A in serial plasma samples of three individual patients. We also performed standard genotype HIV drug resistance assay in 204 patients of this cohort study to analyze the frequency of these mutations.ResultIn the SGA sequences, the K103N decreased and vanished, while the frequency of Y181C and G190A increased in individual patient receiving long-term Antiretroviral Therapy (ART). In the sequences of standard genotype HIV drug resistance assay, the frequency of K103N, Y181C and G190A had the similar pattern with that in SGA sequences. Among these patients, the viral suppression were still sufficient after receiving ART for 72 months, and 78.6% (160/204) patients could have their CD4 count over than 200cells/ul.ConclusionIn some patients, first-line ART had the possibility to provide sufficient treatment effect for over than 72 months, but in long-term treatment, the dominant NNRTI drug resistance mutation K103N could reduced, while the proportion of variants with mutation Y181C or G190A may increased. This result was not similar with that in vitro study, which state that variant with K103N or Y181C had an equal viral fitness with wild type.

Primary drug resistance at diagnosis of HIV-1 infection: a Portuguese cohort.

IntroductionPresence of viral mutations conferring resistance to antiretroviral drugs has potential impact on success of antiretroviral therapy (ART). The aim of this study was to describe the prevalence of resistance-associated mutations in HIV-infected patients without prior ART in a Portuguese cohort.Materials and MethodsRetrospective single-centre study of patients newly diagnosed with HIV-1 infection between 2006 and 2012. Resistance genotyping was obtained with HIV TRUGENE® and Viroseq® tests and the analysis of drug resistance was based on the Stanford University HIV Drug Resistance Database. Epidemiological data was also gathered. Continuous variables were summarized by mean and standard deviation, whereas categorical variables were presented as proportions. Comparison of proportions was performed with Chi square and Fisher exact test while means were compared with Student test. Statistical significance was assumed when p<0.05. Statistical analysis was performed with SPSS 21.0®.ResultsResistance testing was performed in 624 patients. General characteristics of the patients are summarized in Table 1. Mutations were found in 291 (46.6%) patients but resistance-associated mutations were present in 79 (12.7%) patients. Resistances to different drug classes were the following: NNRTIs-resistance in 42 (6.7%) patients; NRTIs-resistance in 19 (3.0%) patients; PIs-resistance in 30 (4.8%) patients. Only 10 (1.6%) patients presented simultaneous resistance-associated mutations to more than one class of drugs. There were no statistical significant differences between the years at which HIV-1 was diagnosed. Also no significant difference in the distribution of the parameters age, sex, CD4-cell count, and viral load, between groups with and without resistance was identified. Resistance-associated mutations were significantly more common in patients with non-B HIV-1 subtypes (15.4% vs 9.8%; p=0.048) and in those presenting with AIDS (18.2% vs 11.1%; p=0.03).ConclusionsPrevalence of resistance-associated mutations identified in this study was similar to those reported in similar studies from Western Europe. Knowledge about the epidemiology of primary resistance in our country is important in order to improve HIV care.

Investigation of HIV-1 primary drug resistance mutations in antiretroviral therapy-naive cases

Following the report of the first AIDS case in Turkey in 1985, the total number of HIV-positive and AIDS cases is 6802 near the end of June 2013, according to the data obtained from the Turkish Ministry of Health. Although combined antiretroviral drug therapy has greatly improved the life-span and the life quality of the patients, HIV-1 drug resistance poses a major obstacle for treatment outcome. The aim of this study was to detect the presence of primary drug resistance in antiretroviral therapy-naive cases. Plasma samples obtained from 190 cases (143 male, 28 female, 19 unknown; age range: 20-72 yrs; mean age: 34.7 yrs) sent to AIDS Confirmation Center of Turkish Public Health Institution, from different provinces of Turkey (Ankara: 64; Adana: 42; Istanbul: 20; Antalya: 13; Gaziantep: 11; Erzurum: 5; Elazig: 3; Malatya: 3; Mersin: 3; and 26 samples from other 21 regions) for routine HIV-1 genotyping test between May 2010-April 2014 period were included in the study. In viral pol gene, complete protease encoding sequence and the first 335 codons of reverse transcriptase (RT) encoding sequence were analyzed by Sanger population-based sequencing method with a commercial test kit (ViroSeq, Abbott/Celera Diagnostics, USA). An alternative in house PCR method with different set of primers was used when the commercial test failed. Primary drug resistance mutations were identified according to the WHO 2009 drug resistance surveillance list. The mean HIV-RNA level at the time of resistance testing was 5.07 (range, 2.09-7.67) log10 copies/ml and the median CD4+ T cell count was 280.3 (range, 0-1000) cells/mm³. The period between the diagnosis of HIV infection and HIV-1 drug resistance test was 18.4 (range, 0-973) weeks. Most prevalent HIV-1 subtypes were subtype B (31%); recombinant B, F1 (24.7%), sub-subtype A1 (16.8%), recombinant B/CRF02_AG (10.5%) and CRF02_G (7.8%). Analysis of our results showed that 10% (19/190) of the samples exhibited resistance mutations. Detected mutations were as follows: M41L, K70E, M184V, L210W and T215C/D/S, responsible for nucleoside RT inhibitor (NRTI) resistance; K103N/S and Y181C, responsible for non-nucleoside RT inhibitor (NNRTI) resistance; M46L and L90M, responsible for protease inhibitor (PI) resistance. NRTI, NNRTI and PI mutation rates in the samples were found as 5.2%, 3.1% and 2.1%, respectively. Both NRTI and NNRTI mutations were detected in one sample. Two mutations leading to NRTI resistance were obtained together in five samples. Seven out of the 19 strains with primary resistance mutation were isolated from samples sent from Ankara, three from Adana, two of each from Istanbul, Erzurum and Mersin, and one of each from Amasya, Samsun and Tokat provinces. There were no statistically significant differences in terms of age, gender, CD4⁺ T cell count, time from diagnosis to resistance testing between the patient group with primary drug resistance and the group without resistance (p> 0.05). However, the mean HIV-RNA level in patients with primary drug resistance [4.77 (2.95-6.87) log(10) copies/ml] was significantly lower than those without primary drug resistance [5.11 (2.09-7.67) log10 copies/ml] (p= 0.043). Our results revealed a relatively high (10%) prevalence of HIV-1 primary drug resistance. We therefore support the need for routine HIV resistance testing so that clinicians can individualize their treatments taking into account the presenting drug resistance.

Genotyping and virological characteristics of hepatitis B virus in HIV-infected individuals in Sudan

Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) share common routes of blood-borne transmission. In HBV mono-infected Sudanese individuals, genotypes D, E, and A circulate. The objective of this study was to molecularly characterize HBV from HBV/HIV co-infected individuals. The polymerase overlapping the S region and the basic core promoter (BCP/PC) of HBV from 32 hepatitis B surface antigen (HBsAg)-positive and 18 HBsAg-negative serum samples were amplified and sequenced. HBV from 37 samples was successfully genotyped and the genotype distribution was 46.0% D, 21.6% E, 18.9% A, and 13.5% D/E recombinant. Compared to mono-infected individuals, the frequencies of the D/E recombinant and genotype A were higher in HBV/HIV co-infected patients, as was the intra-group divergence of genotype E. BCP/PC mutations affecting hepatitis B e antigen (HBeAg) expression at the transcriptional and translational levels were detected. Two HBsAg-positive individuals had pre-S deletion mutants. The following mutations in the S region could account for the HBsAg negativity: sM133T, sE164G, sV168G, and sS174N. No primary drug resistance mutations were found. In HBV/HIV co-infected Sudanese patients, the ratio of genotype A to non-A was higher than that in mono-infected patients. The genotype E intra-group divergence in HBV/HIV co-infected individuals was significantly higher than that in HBV mono-infected patients.