Drug Resistance Mutations Research Articles

Use of next-generation sequencing on HIV-1 DNA to assess archived resistance in highly treatment-experienced people with multidrug-resistant HIV under virological control: data from the PRESTIGIO Registry.

To clarify whether next-generation sequencing (NGS) can be useful for resistance assessment in virologically suppressed highly treatment-experienced (HTE) individuals with MDR HIV. Ninety-one participants from the PRESTIGIO Registry were included. NGS was performed on HIV-DNA at 1%, 5% and 20% cut-offs; major drug resistance mutations (DRMs) were evaluated and compared with those detected in historical plasma genotypic resistance testing (h-GRT). APOBEC editing was also characterized. Participants had a complex and long treatment history [median 23 (IQR 21-25) years of ART exposure) and had been virologically suppressed since a median of 3 (IQR 2-5) years. Among all major DRMs detected by HIV-DNA NGS and/or h-GRT, 30% were exclusively found through NGS. The highest detection rate of historical major DRMs was reached with NGS set at 1%, but unusual substitutions and extensive APOBEC hypermutations suggest technical issues and poor clinical relevance in the 1%-5% interval. At NGS set at 5%, 67.2% of historical major DRMs were detected. The number of major DRMs detected exclusively by DNA-NGS as minority variants (frequency 5%-20%) was significantly higher in individuals who later experienced virological rebound compared with those who maintained virological control [median 2 (IQR 1-3) versus 1 (0-2), P = 0.030] and positively correlated with viraemia levels at rebound (rho = 0.474, P = 0.030). In non-viraemic people with an MDR virus, HIV-1 DNA NGS set at 5% is an acceptable technical cut-off that might help to reveal mutations with a potential clinical relevance. Moreover, the number of minority resistance mutations additionally detected by NGS might be associated with loss of virological control.

Retrospective study of the prevalence of acquired drug resistance after failed antiretroviral therapy in Libya

Background: The increasing rate of drug-resistant HIV mutations in Libya and other African countries threatens the efficacy of antiretroviral therapy (ART), thus necessitating urgent regional strategies to combat resistance and improve treatment outcomes. Aim: To characterize the frequency and pattern of acquired HIV drug resistance mutations in patients showing ART failure while using non-nucleoside reverse transcriptase inhibitors (NNRTI) prescribed by the Department of Infectious Diseases at Tripoli University Hospital, Libya. Methods: We collated retrospective data on 128 people living with HIV, aged 18 years or above, who experienced firstline treatment failure at Tripoli University Hospital, Libya, from 2014 to 2017. We analysed the extant HIV amino acid sequences to identify resistance mutations using algorithms from the Stanford University HIV drug resistance database. Findings: All included cases had at least one resistance mutation (n = 128; 100%) and 119 (93%) had both nucleoside reverse transcriptase inhibitors (NRTI) and NNRTI mutations. M184V/I was the most common NRTI mutation (n = 119; 93%) while K103N was the most common NNRTI mutation (n = 100; 78%). Thymidine analog mutations were detected in 51 cases (40%); featuring T215Y, D67N and M41L. Predicted full susceptibility was highest for Tenofovir (66.4%), followed by Etravirine (60%). Conclusion: We detected high level drug resistance and associated mutations among people living with HIV. Implementing drug regimens with high genetic barriers to resistance, coupled with rigorous monitoring and surveillance of HIV resistance development, could help mitigate such resistance in the future.

Long-term stability of acquired drug resistance and resistance associated mutations in the fungal pathogen Nakaseomyces glabratus (Candida glabrata).

The limited number of available antifungal drugs and the increasing number of fungal isolates that show drug or multidrug resistance pose a serious medical threat. Several yeast pathogens, such as Nakaseomyces glabratus (Candida glabrata), show a remarkable ability to develop drug resistance during treatment through the acquisition of genetic mutations. However, how stable this resistance and the underlying mutations are in non-selective conditions remains poorly characterized. The stability of acquired drug resistance has fundamental implications for our understanding of the appearance and spread of drug-resistant outbreaks and for defining efficient strategies to combat them. Here, we used an in vitro evolution approach to assess the stability under optimal growth conditions of resistance phenotypes and resistance-associated mutations that were previously acquired under exposure to antifungals. Our results reveal a remarkable stability of the resistant phenotype and the underlying mutations in a significant number of evolved populations, which conserved their phenotype for at least two months in the absence of drug-selective pressure. We observed a higher stability of anidulafungin resistance over fluconazole resistance, and of resistance-conferring point mutations as compared with aneuploidies. In addition, we detected accumulation of novel mutations in previously altered resistance-associated genes in non-selective conditions, which suggest a possible compensatory role. We conclude that acquired resistance, particularly to anidulafungin, is a long-lasting phenotype, which has important implications for the persistence and propagation of drug-resistant clinical outbreaks.

Genetic diversity accelerates canine distemper virus adaptation to ferrets.

RNA viruses adapt rapidly to new host environments by generating highly diverse genome sets, so-called "quasispecies." Minor genetic variants promote their rapid adaptation, allowing for the emergence of drug-resistance or immune-escape mutants. Understanding these adaptation processes is highly relevant to assessing the risk of cross-species transmission and the safety and efficacy of vaccines and antivirals. We hypothesized that genetic memory within a viral genome population facilitates rapid adaptation. To test this, we investigated the adaptation of the Morbillivirus canine distemper virus to ferrets and compared an attenuated, Vero cell-adapted virus isolate with its recombinant derivative over consecutive ferret passages. Although both viruses adapted to the new host, the reduced initial genetic diversity of the recombinant virus resulted in delayed disease onset. The non-recombinant virus gradually increased the frequencies of beneficial mutations already present at very low frequencies in the input virus. In contrast, the recombinant virus first evolved de novo mutations to compensate for the initial fitness impairments. Importantly, while both viruses evolved different sets of mutations, most mutations found in the adapted non-recombinant virus were identical to those found in a previous ferret adaptation experiment with the same isolate, indicating that mutations present at low frequency in the original virus stock serve as genetic memory. An arginine residue at position 519 in the carboxy terminus of the nucleoprotein shared by all adapted viruses was found to contribute to pathogenesis in ferrets. Our work illustrates the importance of genetic diversity for adaptation to new environments and identifies regions with functional relevance.IMPORTANCEWhen viruses encounter a new host, they can rapidly adapt to this host and cause disease. How these adaptation processes occur remains understudied. Morbilliviruses have high clinical and veterinary relevance and are attractive model systems to study these adaptation processes. The canine distemper virus is of particular interest, as it exhibits a broader host range than other morbilliviruses and frequently crosses species barriers. Here, we compared the adaptation of an attenuated virus and its recombinant derivative to that of ferrets. Pre-existing mutations present at low frequency allowed faster adaptation of the non-recombinant virus compared to the recombinant virus. We identified a common point mutation in the nucleoprotein that affected the pathogenesis of both viruses. Our study shows that genetic memory facilitates environmental adaptation and that erasing this genetic memory by genetic engineering results in delayed and different adaptation to new environments, providing an important safety aspect for the generation of live-attenuated vaccines.

Two decades of molecular surveillance in Senegal reveal rapid changes in known drug resistance mutations over time

BackgroundDrug resistance in Plasmodium falciparum is a major threat to malaria control efforts. Pathogen genomic surveillance could be invaluable for monitoring current and emerging parasite drug resistance.MethodsData from two decades (2000–2020) of continuous molecular surveillance of P. falciparum parasites from Senegal were retrospectively examined to assess historical changes in malaria drug resistance mutations. Several known drug resistance markers and their surrounding haplotypes were profiled using a combination of single nucleotide polymorphism (SNP) molecular surveillance and whole genome sequence based population genomics.ResultsThis dataset was used to track temporal changes in drug resistance markers whose timing correspond to historically significant events such as the withdrawal of chloroquine (CQ) and the introduction of sulfadoxine-pyrimethamine (SP) in 2003. Changes in the mutation frequency at Pfcrt K76T and Pfdhps A437G coinciding with the 2014 introduction of seasonal malaria chemoprevention (SMC) in Senegal were observed. In 2014, the frequency of Pfcrt K76T increased while the frequency of Pfdhps A437G declined. Haplotype-based analyses of Pfcrt K76T showed that this rapid increase was due to a recent selective sweep that started after 2014.Discussion (Conclusion)The rapid increase in Pfcrt K76T is troubling and could be a sign of emerging amodiaquine (AQ) resistance in Senegal. Emerging AQ resistance may threaten the future clinical efficacy of artesunate-amodiaquine (ASAQ) and AQ-dependent SMC chemoprevention. These results highlight the potential of molecular surveillance for detecting rapid changes in parasite populations and stress the need to monitor the effectiveness of AQ as a partner drug for artemisinin-based combination therapy (ACT) and for chemoprevention.

Deviated binding of anti-HBV nucleoside analog E-CFCP-TP to the reverse transcriptase active site attenuates the effect of drug-resistant mutations

While certain human hepatitis B virus-targeting nucleoside analogs (NAs) serve as crucial anti-HBV drugs, HBV yet remains to be a major global health threat. E-CFCP is a 4′-modified and fluoromethylenated NA that exhibits potent antiviral activity against both wild-type and drug-resistant HBVs but less potent against human immunodeficiency virus type-1 (HIV-1). Here, we show that HIV-1 with HBV-associated amino acid substitutions introduced into the RT’s dNTP-binding site (N-site) is highly susceptible to E-CFCP. We determined the X-ray structures of HBV-associated HIV-1 RT mutants complexed with DNA:E-CFCP-triphosphate (E-CFCP-TP). The structures revealed that exocyclic fluoromethylene pushes the Met184 sidechain backward, and the resultant enlarged hydrophobic pocket accommodates both the fluoromethylene and 4′-cyano moiety of E-CFCP. Structural comparison with the DNA:dGTP/entecavir-triphosphate complex also indicated that the cyclopentene moiety of the bound E-CFCP-TP is slightly skewed and deviated. This positioning partly corresponds to that of the bound dNTP observed in the HIV-1 RT mutant with drug-resistant mutations F160M/M184V, resulting in the attenuation of the structural effects of F160M/M184V substitutions. These results expand our knowledge of the interactions between NAs and the RT N-site and should help further design antiviral NAs against both HIV-1 and HBV.

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

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

Antiviral activity of luteolin against porcine epidemic diarrhea virus in silico and in vitro

BackgroundPorcine epidemic diarrhea virus (PEDV) mainly causes acute and severe porcine epidemic diarrhea (PED), and is highly fatal in neonatal piglets. No reliable therapeutics against the infection exist, which poses a major global health issue for piglets. Luteolin is a flavonoid with anti-viral activity toward several viruses.ResultsWe evaluated anti-viral effects of luteolin in PEDV-infected Vero and IPEC-J2 cells, and identified IC50 values of 23.87 µM and 68.5 µM, respectively. And found PEDV internalization, replication and release were significantly reduced upon luteolin treatment. As luteolin could bind to human ACE2 and SARS-CoV-2 main protease (Mpro) to contribute viral entry, we first identified that luteolin shares the same core binding site on pACE2 with PEDV-S by molecular docking and exhibited positive pACE2 binding with an affinity constant of 71.6 µM at dose-dependent increases by surface plasmon resonance (SPR) assay. However, pACE2 was incapable of binding to PEDV-S1. Therefore, luteolin inhibited PEDV internalization independent of PEDV-S binding to pACE2. Moreover, luteolin was firmly embedded in the groove of active pocket of Mpro in a three-dimensional docking model, and fluorescence resonance energy transfer (FRET) assays confirmed that luteolin inhibited PEDV Mpro activity. In addition, we also observed PEDV-induced pro-inflammatory cytokine inhibition and Nrf2-induced HO-1 expression. Finally, a drug resistant mutant was isolated after 10 cell culture passages concomitant with increasing luteolin concentrations, with reduced PEDV susceptibility to luteolin identified at passage 10.ConclusionsOur results push forward that anti-PEDV mechanisms and resistant-PEDV properties for luteolin, which may be used to combat PED.

Genotyping and Antiretroviral Drug Resistance Mutations among HIV Patients in Southern Santa Catarina, Brazil.

Therapeutic measures have been successful in increasing survival rates and quality of life of HIV/AIDS-infected people. However, some people fail to respond to antiretroviral therapy (HAART) because of viral resistance-associated mutations. To identify virus genotype and the presence of mutations that alter the susceptibility to HAART, and factors associated with the occurrence of these mutations. A cross-sectional study was conducted on adults living with HIV attending a specialized outpatient clinic in southern Santa Catarina, Brazil. The participants were interviewed and had blood samples collected for analysis. Those with detectable viral load were genotyped. Out of the 629 patients recruited, 127 subjects were included due to having a detectable viral load. The most common mutations were M184V and K103N. HIV-1 subtype C was the most prevalent strain. Resistance to HAART was associated with modification in the treatment regimen (p <0.001). This study concluded that the circulating subtype virus was subtype C and that the mutations K103N and M184V were the most prevalent strains in southern Santa Catarina, Brazil.

HIV-DRIVES: HIV drug resistance identification, variant evaluation, and surveillance pipeline.

The global prevalence of resistance to antiviral drugs combined with antiretroviral therapy (cART) emphasizes the need for continuous monitoring to better understand the dynamics of drug-resistant mutations to guide treatment optimization and patient management as well as check the spread of resistant viral strains. We have recently integrated next-generation sequencing (NGS) into routine HIV drug resistance (HIVDR) monitoring, with key challenges in the bioinformatic analysis and interpretation of the complex data generated, while ensuring data security and privacy for patient information. To address these challenges, here we present HIV-DRIVES (HIV Drug Resistance Identification, Variant Evaluation, and Surveillance), an NGS-HIVDR bioinformatics pipeline that has been developed and validated using Illumina short reads, FASTA, and Sanger ab1.seq files.

Human Immunodeficiency Viral Reverse Transcriptases: Analyses of the Active Sites of the Polymerase Domain and Drug-Resistant Mutants of the Reverse Transcriptases

It is well-known that human immunodeficiency viruses (HIVs) cause the chronic, potentially life-threatening condition known as human Acquired Immuno-Deficiency Syndrome (AIDS). As the lifecycle of HIVs heavily depends on the crucial enzyme, the reverse transcriptase (RT), it has been used as a potential therapeutic target to treat and control the spread of AIDS. The active site amino acids of the polymerase domain of the RTs and their anti-HIV drug-binding sites are analyzed. The catalytic region of HIV RTs and the E. coli DNA polymerase I showed very similar active site amino acids, suggesting that HIV RTs would have possibly evolved from the bacterial DNA polymerase. The catalytic proton abstractor is identified as a K and the nucleotide selection amino acid as an N. However, the regular template-binding pair –YG- is slightly modified to a –YXG- in HIV RTs. Three completely conserved Ds in HIV RTs are involved in binding to the catalytic Mg2+. The sensitive and resistant strains of HIV-1 for the HIV antiretroviral drug, azidothymidine (AZT), a nucleoside analogue of thymidine, show only a few non-isofunctional amino acid replacements and are located mainly in the palm and thumb subdomains of the RT polymerase, whereas the rest of the polymerase catalytic core and metal-binding sites are completely conserved in AZT-sensitive and -resistant HIV-1 strains. In the drug-resistant mutants of non-nucleoside RT inhibitors of HIV-2, the crucial mutations are located mainly near the -MDD- motif of the catalytic metal-binding region. Even though a large number of amino acid replacements are seen between the RTs of HIV-1 and HIV-2, the polymerase active sites are completely conserved in both. The HIV-1 and HIV-2 catalytic and metal-binding sites are completely conserved in simian immunodeficiency virus (SIV) as well. The absence of DEDD-superfamily of proofreading exonuclease domain in the HIV RTs, might cause the virus to evolve rapidly in patients. A possible mechanism of action for the HIV RTs is also proposed.

Impact of Human Immunodeficiency Virus Drug Resistance Mutations Detected in Women Prior to Antiretroviral Therapy With Efavirenz + Tenofovir Disoproxil Fumarate + Lamivudine (or Emtricitabine).

Two large studies suggest that resistance mutations to only nonnucleoside reverse transcriptase inhibitors (NNRTI) did not increase the risk of virologic failure during antiretroviral therapy (ART) with efavirenz/tenofovir disoproxil fumarate/lamivudine (or emtricitabine). We retrospectively evaluated a third cohort to determine the impact of NNRTI resistance on the efficacy of efavirenz-based ART. Postpartum women living with human immunodeficiency virus (HIV) were studied if they initiated efavirenz-based ART because of the World Health Organization's recommendation for universal ART. Resistance was detected by Sanger genotyping plasma prior to efavirenz-based ART and at virologic failure (HIV RNA >400 copies/mL). Logistic regression examined relationships between pre-efavirenz genotypes and virologic failure. Pre-efavirenz resistance was detected in 169 of 1223 (13.8%) participants. By month 12 of efavirenz-based ART, 189 of 1233 (15.3%) participants had virologic failure. Rates of virologic failure did not differ by pre-efavirenz NNRTI resistance. However, while pre-efavirenz nucleos(t)ide reverse transcriptase inhibitors (NRTI) and NNRTI resistance was rare (8/1223 [0.7%]) this genotype increased the odds (adjusted odds ratio, 11.2 [95% confidence interval, 2.21-72.2]) of virologic failure during efavirenz-based ART. Age, time interval between last viremic visit and efavirenz initiation, clinical site, viremia at delivery, hepatitis B virus coinfection, and antepartum regimen were also associated with virologic failure. Resistance to NNRTI alone was prevalent and dual-class (NRTI and NNRTI) resistance was rare in this cohort, with only the latter associated with virologic failure. This confirms others' findings that, if needed, efavirenz-based ART offers most people an effective alternative to dolutegravir-based ART.

Immunological and molecular assessment of HIV-1 mutations for antiretroviral drug resistance in Saudi Arabia.

Human Immunodeficiency Virus (HIV) is a significant threat to public health. HIV genotyping and antiretroviral resistance testing may have contributed to improved non-treated management. Immune markers might assist HIV-1 diagnosis and drug-resistant variant identification. HIV-1 immunogenicity and molecular characteristics of antiretroviral drug resistance are evaluated in 56 treatment-naive HIV patients. DNA sequencing and retroviral resistance testing identified HIV-1 genotypes. 55.4% of patients were susceptible to protease inhibitors (PI), nucleoside reverse transcriptase inhibitors (NRTI), and non-nucleoside reverse transcriptase inhibitors (NNRTI) antiretroviral drugs, whereas 44.6% had drug-resistance mutations against at least one antiretroviral drug. 3.6% of cases had PI-resistant mutations, while 30.4% had NRTI-resistant mutations, and 30.4% had NNRTI-resistant mutations. In patients who are susceptible to PI, the mean value of human plasma sCD80 is 2.11 ± 0.65 ng/mL; in patients with mutations, it is 3.93 ± 2.91 ng/mL. Individuals who are susceptible to PI have plasma sCD27 levels of 78.7 ± 63.2 U/mL, whereas individuals who are mutant have levels of 56.5 ± 32.1 U/mL. IP-10's mean value was 363 ± 109.2 pg/mL for the susceptible patients and 429 ± 20.7 pg/mL for the mutated patients. In susceptible patients, the plasma sCD4 level is 0.163 ± 0.229 ng/mL; in mutant patients, it is 0.084 ± 0.012 ng/mL. The data showed a relative relation between immunological parameters such as sCD80, sCD27, sCD4, and IP-10 and mutation for drug resistance.

Detecting drug-resistant human cytomegalovirus mutations in liver transplant recipients: A study of the UL97 gene

Human cytomegalovirus (HCMV or HHV-5) is a member of the beta herpesvirus family and remains dormant for life after the initial infection. However, if conditions such as immunosuppression occur, the virus can become active again and lead to severe diseases. The incidence of disease in solid organ transplant (SOT) recipients is reduced by prophylactic use of ganciclovir (either intravenously or orally). This study aimed to determine the pattern of clinical mutations associated with the cytomegalovirus UL97 gene after treatment with ganciclovir and the effect of these mutations on disease progression in liver transplant recipients infected with Iranian HCMV strains. Six HCMV-positive liver transplant recipients were enrolled, comprising 3 (50.0 %) males and 3 (50.0 %) females. Sequence analysis and mutation detection were performed using Finch software (version 1.4.0) and the NCBI Nucleotide Blast database, whereas phylogenetic analysis was performed using MEGA X (version 10.0.5). Mann-Whitney U nonparametric test, Chi-square test, Spearman's correlation coefficient analysis, were employed for statistical analysis. The results of the study showed that two samples from two patients had mutations in the UL97 gene, and the viral load of the mutated samples decreased after administering antiviral medications. Furthermore, the phylogenetic tree demonstrated a close relationship between the Iranian HCMV strains and global reference sequences.

A Plasmodium falciparum genetic cross reveals the contributions of pfcrt and plasmepsin II/III to piperaquine drug resistance.

Piperaquine (PPQ) is widely used in combination with dihydroartemisinin as a first-line treatment against malaria. Multiple genetic drivers of PPQ resistance have been reported, including mutations in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) and increased copies of plasmepsin II/III (pm2/3). We generated a cross between a Cambodia-derived multidrug-resistant KEL1/PLA1 lineage isolate (KH004) and a drug-susceptible Malawian parasite (Mal31). Mal31 harbors a wild-type (3D7-like) pfcrt allele and a single copy of pm2/3, while KH004 has a chloroquine-resistant (Dd2-like) pfcrt allele with an additional G367C substitution and multiple copies of pm2/3. We recovered 104 unique recombinant parasites and examined a targeted set of progeny representing all possible combinations of variants at pfcrt and pm2/3. We performed a detailed analysis of competitive fitness and a range of PPQ susceptibility phenotypes with these progenies, including PPQ survival assay, area under the dose response curve, and a limited point IC50. We find that inheritance of the KH004 pfcrt allele is required for reduced PPQ sensitivity, whereas copy number variation in pm2/3 further decreases susceptibility but does not confer resistance in the absence of additional mutations in pfcrt. A deep investigation of genotype-phenotype relationships demonstrates that progeny clones from experimental crosses can be used to understand the relative contributions of pfcrt, pm2/3, and parasite genetic background to a range of PPQ-related traits. Additionally, we find that the resistance phenotype associated with parasites inheriting the G367C substitution in pfcrt is consistent with previously validated PPQ resistance mutations in this transporter.IMPORTANCEResistance to piperaquine, used in combination with dihydroartemisinin, has emerged in Cambodia and threatens to spread to other malaria-endemic regions. Understanding the causal mutations of drug resistance and their impact on parasite fitness is critical for surveillance and intervention and can also reveal new avenues to limiting the evolution and spread of drug resistance. An experimental genetic cross is a powerful tool for pinpointing the genetic determinants of key drug resistance and fitness phenotypes and has the distinct advantage of quantifying the effects of naturally evolved genetic variation. Our study was strengthened since the full range of copies of KH004 pm2/3 was inherited among the progeny clones, allowing us to directly test the role of the pm2/3 copy number on resistance-related phenotypes in the context of a unique pfcrt allele. Our multigene model suggests an important role for both loci in the evolution of this multidrug-resistant parasite lineage.

Non-Analog Compounds to Sialic Acid as Inhibitors of Influenza Virus Neuraminidase: An Underexplored Approach for Novel Antivirals―Systematic Review

Influenza poses a significant threat to public health worldwide, particularly among vulnerable populations such as children, the elderly, immunocompromised individuals, and those with chronic diseases. It is associated with high mortality and morbidity rates. Neuraminidase inhibitors play a crucial role in influenza treatment by mitigating the risk of complications and death. However, the genetic variability of the influenza virus enables the emergence of drug-resistant mutations. This review focuses on the search for new compounds that are not analogous to sialic acid, aiming to inhibit the activity of viral neuraminidase in vitro, viral replication in cell cultures, or animal models. Influenza virus strains that have been reported in the literature present specific mutations that generate resistance to neuraminidase inhibitors. Since these inhibitors bear structural resemblance to sialic acid, the predominant location for these mutations is the enzyme’s active site. Consequently, exploring alternative compound classes becomes imperative to circumvent this interaction pattern. These compounds will introduce diverse molecular frameworks, serving as foundational structures for further development through rational drug design, thereby engendering novel antiviral agents targeting influenza. The potential prospects for developing novel influenza antivirals based on these findings are discussed.

HIV Subtypes and Drug-resistance-associated Mutations in US Blood Donors, 2015-2020.

Monitoring genotypes of HIV infections in blood donors may provide insights into infection trends in the general population. HIV RNA was extracted from plasma samples of blood donors confirmed as HIV positive by blood screening nucleic acid and antibody tests. HIV genome target regions were amplified using nested real time-polymerase chain reaction followed by next-generation sequencing. Sequences were compared to those in the Los Alamos National Laboratory (LANL) database. Sequences were also assessed for drug resistance mutations (DRM) using the Stanford HIV DRM Database. From available HIV-positive donations collected between 1 September 2015 and 31 December 2020, 563 of 743 (75.8%) were successfully sequenced; 4 were subtype A, 543 subtype B, 5 subtype C, 1 subtype G, 5 circulating recombinant forms (CRF), and 2 were subtype B and D recombinants. Overall, no significant differences between blood donor and available LANL genotypes were found, and the genotypes of newly acquired versus prevalent HIV infections in donors were similar. The proportion of non-B subtypes and CRF remained a small fraction, with no other subtype or CRF representing more than 1% of the total. DRM were identified in 122 (21.6%) samples with protease inhibitor, nucleoside reverse transcriptase inhibitor and non-nucleoside reverse transcriptase inhibitor DRMs identified in 4.9%, 4.6% and 14.0% of samples, respectively. HIV genetic diversity and DRM in blood donors appear representative of circulating HIV infections in the US general population and may provide more information on infection diversity than sequences reported to LANL, particularly for recently transmitted infections.

Alkynyl nicotinamides show antileukemic activity in drug-resistant acute myeloid leukemia.

Activating mutations of FLT3 contribute to deregulated hematopoietic stem and progenitor cell (HSC/Ps) growth and survival in patients with acute myeloid leukemia (AML), leading to poor overall survival. AML patients treated with investigational drugs targeting mutant FLT3, including Quizartinib and Crenolanib, develop resistance to these drugs. Development of resistance is largely due to acquisition of cooccurring mutations and activation of additional survival pathways, as well as emergence of additional FLT3 mutations. Despite the high prevalence of FLT3 mutations and their clinical significance in AML, there are few targeted therapeutic options available. We have identified 2 novel nicotinamide-based FLT3 inhibitors (HSN608 and HSN748) that target FLT3 mutations at subnanomolar concentrations and are potently effective against drug-resistant secondary mutations of FLT3. These compounds show antileukemic activity against FLT3ITD in drug-resistant AML, relapsed/refractory AML, and in AML bearing a combination of epigenetic mutations of TET2 along with FLT3ITD. We demonstrate that HSN748 outperformed the FDA-approved FLT3 inhibitor Gilteritinib in terms of inhibitory activity against FLT3ITD in vivo.

Hepatitis B Virus Prevalence among HIV-Uninfected People Living in Rural and Peri-Urban Areas in Botswana.

(1) Background: we determined the prevalence of the hepatitis B virus (HBV) amongst people without human immunodeficiency virus (HIV) in rural and peri-urban areas in Botswana. (2) Methods: We screened for the hepatitis B surface antigen (HBsAg) from archived plasma samples of people without HIV (n = 2135) randomly selected from the Botswana Combination Prevention Program (BCPP) (2013-2018). We sequenced 415 bp of the surface region using BigDye sequencing chemistry. (3) Results: The median age of participants was 31 (IQR: 24-46) and 64% (1360/2135) were female. HBV prevalence was 4.0% (86/2135) [95% CI: 3.3-4.9]) and ranged between 0-9.2%. Older participants (>35 years) had increased odds of HBV positivity (OR: 1.94; 95% CI: [1.32-2.86]; p = 0.001). Thirteen samples were sequenced and seven (53.8%) were genotype A, three (23.1%) were genotype D and genotype E each. Clinically significant mutations were identified in the surface region, but no classic drug resistance mutations were identified. (4) Conclusions: We report an HBV prevalence of 4.0% (95% CI 3.3-4.9) among people without HIV in rural and peri-urban communities in Botswana with varying rates in different communities. A comprehensive national HBV program is required in Botswana to guide HBV prevention, testing and management.

Human Immunodeficiency Virus Type-1 Genetic Diversity and Drugs Resistance Mutations among People Living with HIV in Karachi, Pakistan.

The human immunodeficiency virus type-1 epidemic in Pakistan has significantly increased over the last two decades. In Karachi, Pakistan, there is a lack of updated information on the complexity of HIV-1 genetic diversity and the burden of drug resistance mutations (DRMs) that can contribute to ART failure and poor treatment outcomes. This study aimed to determine HIV-1 genetic diversity and identify drug-resistance mutations among people living with HIV in Karachi. A total of 364 HIV-positive individuals, with a median age of 36 years, were enrolled in the study. The HIV-1 partial pol gene was successfully sequenced from 268 individuals. The sequences were used to generate phylogenetic trees to determine clade diversity and also to assess the burden of DRMs. Based on the partial pol sequences, 13 distinct HIV-1 subtypes and recombinant forms were identified. Subtype A1 was the most common clade (40%), followed by CRF02_AG (33.2%). Acquired DRMs were found in 30.6% of the ART-experienced patients, of whom 70.7%, 20.7%, and 8.5% were associated with resistance to NNRTIs, NRTIs, and PIs, respectively. Transmitted DRMs were found in 5.6% of the ART-naïve patients, of whom 93% were associated with resistance against NNRTIs and 7% to PIs. The high prevalence of DRMs in ART-experienced patients poses significant challenges to the long-term benefits and sustainability of the ART program. This study emphasizes the importance of continuous HIV molecular epidemiology and drug resistance surveillance to support evidence-based HIV prevention, precise ART, and targeted AIDS care.