Antiviral Susceptibility of Highly Pathogenic Avian Influenza A(H5N1) Viruses Circulating Globally in 2022-2023.

The antiviral susceptibility of currently circulating (2022-2023) highly pathogenic avian influenza (HPAI) A(H5N1) viruses was assessed by genotypic and phenotypic approaches. The frequency of neuraminidase (NA) and polymerase acidic (PA) substitutions associated with reduced inhibition by NA inhibitors (NAIs) (21/2698, 0.78%) or by the PA inhibitor baloxavir (14/2600, 0.54%) was low. Phenotypic testing of 22 clade 2.3.2.1a and 2.3.4.4b viruses revealed broad susceptibility to NAIs and baloxavir concluding that most contemporary HPAI A(H5N1) viruses retain susceptibility to antiviral drugs. Novel NA-K432E and NA-T438I substitutions (N2 numbering) were identified at elevated frequencies (104/2698, 3.85%) and caused reduced zanamivir and peramivir inhibition.

Neuraminidase inhibition improves endothelial function in diabetic mice.

Neuraminidases cleave sialic acids from glycocalyx structures and plasma neuraminidase activity is elevated in type 2 diabetes (T2D). Therefore, we hypothesize circulating neuraminidase degrades the endothelial glycocalyx and diminishes flow-mediated dilation (FMD), whereas its inhibition restores shear mechanosensation and endothelial function in T2D settings. We found that compared with controls, subjects with T2D have higher plasma neuraminidase activity, reduced plasma nitrite concentrations, and diminished FMD. Ex vivo and in vivo neuraminidase exposure diminished FMD and reduced endothelial glycocalyx presence in mouse arteries. In cultured endothelial cells, neuraminidase reduced glycocalyx coverage. Inhalation of the neuraminidase inhibitor, zanamivir, reduced plasma neuraminidase activity, enhanced endothelial glycocalyx length, and improved FMD in diabetic mice. In humans, a single-arm trial (NCT04867707) of zanamivir inhalation did not reduce plasma neuraminidase activity, improved glycocalyx length, or enhanced FMD. Although zanamivir plasma concentrations in mice reached 225.8 ± 22.0 ng/mL, in humans were only 40.0 ± 7.2 ng/mL. These results highlight the potential of neuraminidase inhibition for ameliorating endothelial dysfunction in T2D and suggest the current Food and Drug Administration-approved inhaled dosage of zanamivir is insufficient to achieve desired outcomes in humans.NEW & NOTEWORTHY This work identifies neuraminidase as a key mediator of endothelial dysfunction in type 2 diabetes that may serve as a biomarker for impaired endothelial function and predictive of development and progression of cardiovascular pathologies associated with type 2 diabetes (T2D). Data show that intervention with the neuraminidase inhibitor zanamivir at effective plasma concentrations may represent a novel pharmacological strategy for restoring the glycocalyx and ameliorating endothelial dysfunction.

Inhaled Zanamivir vs Oral Oseltamivir to Prevent Influenza-related Hospitalization or Death: A Nationwide Population-based Quasi-experimental Study.

BACKGROUND: Meta-analyses of individual patient data from randomized, controlled trials show that early oseltamivir treatment for influenza cut the risk of pneumonia and hospitalization by 44% and 63%, respectively. However, data on the effectiveness of inhaled zanamivir in preventing hospitalization and death are lacking. METHODS: This nationwide, population-based, cohort study included all outpatients treated with inhaled zanamivir or oral oseltamivir within 48 hours after a clinical diagnosis of influenza before and after the rollout of inhaled zanamivir as the first-line antiviral in Taiwan. The main outcome was influenza-related hospitalization or death within 14 days. Those who developed the outcome within 2 days were excluded from analyses. Propensity score stratification was used to control confounding from covariates. RESULTS: A total of 865 032 eligible influenza outpatients were included in the analysis. The risk of developing the main outcome (adjusted hazard ratio [aHR], 1.01; 95% confidence interval [CI], .96 to 1.06) did not differ between the inhaled zanamivir group (n = 595 897, 68.9%, the reference) and the oral oseltamivir group (n = 269 135, 31.1%). Prespecified analysis on high-risk subgroups further showed that inhaled zanamivir is not inferior to oral oseltamivir in either patients aged ≥65 years (aHR, 1.14; 95% CI: 1.05 to 1.25) or patients with chronic lung diseases (aHR, 1.23; 95% CI: 1.08 to 1.41). CONCLUSIONS: Inhaled zanamivir is not inferior to oral oseltamivir as outpatient treatment in preventing influenza-related hospitalization or death for patients whose conditions do not require hospitalization within 2 days.

Alloferon and Zanamivir Show Effective Antiviral Activity against Influenza A Virus (H1N1) Infection In Vitro and In Vivo.

The use of vaccines is the most effective and reliable method for the prevention of viral infections. However, research on evaluation of effective therapeutic agents for use in treatment after infection is necessary. Zanamivir was administered through inhalation for treatment of pandemic influenza A/H1N1 in 2009. However, the emergence of drug-resistant strains can occur rapidly. Alloferon, an immunomodulatory drug developed as an NK cell activator, exerts antiviral effects against various viruses, particularly influenza viruses. Therefore, alloferon and zanamivir were administered in combination in an effort to improve the antiviral effect of zanamivir by reducing H1N1 resistance. First, we confirmed that administration of combined treatment would result in effective inhibition of viral proliferation in MDCK and A549 cells infected with H1N1. Production of IL-6 and MIP-1α in these cells and the activity of p38 MAPK and c-Jun that are increased by H1N1 were inhibited by combined treatment. Mice were then infected intranasally with H1N1, and examination of the antiviral efficacy of the alloferon/zanamivir combination was performed. The results showed that combined treatment after infection with H1N1 prevented weight loss, increased the survival rate, and improved lung fibrosis. Combined treatment also resulted in reduced infiltration of neutrophils and macrophages into the lungs. Combined treatment effectively inhibited the activity of p38 MAPK and c-Jun in lung tissue, which was increased by infection with H1N1. Therefore, the combination of alloferon/zanamivir effectively prevents the development of H1N1-mediated inflammation in the lungs by inhibiting the production of inflammatory mediators and migration of inflammatory cells into lung tissue.

Intravenous Zanamivir: A Viable Option for Critically Ill Patients With Influenza.

OBJECTIVE: To review the pharmacology, clinical trial data, and clinical implications for the intravenous formulation of zanamivir. DATA SOURCES: MEDLINE, PubMed, EMBASE, and Google Scholar were searched during November 2019 to July 2020. Search terms zanamivir and neuraminidase inhibitor were used. STUDY SELECTION AND DATA EXTRACTION: All human trials and major reports from compassionate use programs with the intravenous zanamivir (IVZ) formulation were assessed and reviewed here. DATA SYNTHESIS: IVZ was found to be similar but not superior to oral oseltamivir in hospitalized patients when studied in populations with very low baseline oseltamivir resistance. IVZ provides an effective alternative for critically ill patients when oral antiviral therapy is not preferred or when oseltamivir resistance is increased. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: IVZ was recently authorized for use by the European Medicines Agency, and it is eligible for consideration in emergency use protocols and US stockpile inclusion. It will be of particular interest in critically ill patients especially during influenza seasons with appreciable oseltamivir and peramivir resistance. CONCLUSIONS: The available information suggests that the intravenous formulation of zanamivir offers a viable alternative treatment for critically ill patients with influenza, especially when resistance to other agents is present.

Favipiravir and Zanamivir Cleared Infection with Influenza B in a Severely Immunocompromised Child.

A combination of favipiravir and zanamivir successfully cleared influenza B infection in a child who had undergone bone marrow transplant for X-linked severe combined immunodeficiency, with no recovery of T lymphocytes. Deep sequencing of viral samples illuminated the within-host dynamics of infection, demonstrating the effectiveness of favipiravir in this case.

Influenza A/H4N2 mallard infection experiments further indicate zanamivir as less prone to induce environmental resistance development than oseltamivir.

Neuraminidase inhibitors (NAIs) are the gold standard treatment for influenza A virus (IAV). Oseltamivir is mostly used, followed by zanamivir (ZA). NAIs are not readily degraded in conventional wastewater treatment plants and can be detected in aquatic environments. Waterfowl are natural IAV hosts and replicating IAVs could thus be exposed to NAIs in the environment and develop resistance. Avian IAVs form the genetic basis for new human IAVs, and a resistant IAV with pandemic potential poses a serious public health threat, as NAIs constitute a pandemic preparedness cornerstone. Resistance development in waterfowl IAVs exposed to NAIs in the water environment has previously been investigated in an in vivo mallard model and resistance development was demonstrated in several avian IAVs after the exposure of infected ducks to oseltamivir, and in an H1N1 IAV after exposure to ZA. The N1 and N2 types of IAVs have different characteristics and resistance mutations, and so the present study investigated the exposure of an N2-type IAV (H4N2) in infected mallards to 1, 10 and 100 µg l-1 of ZA in the water environment. Two neuraminidase substitutions emerged, H274N (ZA IC50 increased 5.5-fold) and E119G (ZA IC50 increased 110-fold) at 10 and 100 µg l-1 of ZA, respectively. Reversion towards wild-type was observed for both substitutions in experiments with removed drug pressure, indicating reduced fitness of both resistant viruses. These results corroborate previous findings that the development of resistance to ZA in the environment seems less likely to occur than the development of resistance to oseltamivir, adding information that is useful in planning for prudent drug use and pandemic preparedness.

Reduced Susceptibility to Neuraminidase Inhibitors in Influenza B Isolate, Canada.

We identified an influenza B isolate harboring a Gly407Ser neuraminidase substitution in an immunocompromised patient in Canada before antiviral therapy. This mutation mediated reduced susceptibility to oseltamivir, zanamivir, and peramivir, most likely by preventing interaction with the catalytic Arg374 residue. The potential emergence of such variants emphasizes the need for new antivirals.

Clinical outcomes of patients treated with intravenous zanamivir for severe influenza A(H1N1)pdm09 infection: a case report series.

BACKGROUND: Intravenous (IV) zanamivir could be a suitable alternative for the treatment of severe influenza A(H1N1)pdm09 infection in patients who are unable to take oral or inhaled medication, for example, those on mechanical ventilation and extracorporeal membrane oxygenation (ECMO). However, data on the clinical outcomes of such patients is limited. CASE PRESENTATION: We report the clinical outcomes of four patients who were admitted at the intensive care unit during the 2017-2018 influenza season with severe sepsis (SOFA score > 11) and acute respiratory distress syndrome requiring ECMO and mechanical ventilation. Two patients were immune-compromised. The A(H1N1)pdm09 genome was confirmed by polymerase chain reaction (PCR) on nasopharyngeal specimen swabs prior to administration of IV zanamivir at a dose of 600 mg twice daily. Weekly qualitative PCR analysis was done to monitor viral clearance, with zanamivir treatment being discontinued upon receipt of negative results. In addition, the patients were managed for concomitant multidrug-resistant bacterial infections, with infection resolution confirmed with blood cultures. The median time for zanamivir treatment was 10 days (IQR 10-17). The clinical outcome was favourable with all four patients surviving and improving clinically. All four patients achieved viral clearance of A(H1N1)pdm09 genome, and resolution of multidrug-resistant bacterial infections. CONCLUSIONS: IV zanamivir could be a good therapeutic option in patients with severe influenza A(H1N1)pdm09 infection who are unable to take oral or aerosolised antiviral medication. We recommend prospective randomized control trials to support this hypothesis.

Antiviral treatment and virological monitoring of oseltamivir-resistant influenza virus A(H1N1)pdm09 in a patient with chronic B lymphocytic leukemia.

We report the virological monitoring and the antiviral therapy adopted for the treatment of a patient affected by chronic B lymphocytic leukemia, who experienced a severe pneumonia with long-term shedding of influenza virus A(H1N1)pdm09, characterized by an early development of oseltamivir resistance.

Design, synthesis and biological evaluation of novel zanamivir derivatives as potent neuraminidase inhibitors.

Neuraminidase (NA) is an important antiviral drug target. Zanamivir is one of the most potent NA inhibitors. In this paper, a series of zanamivir derivatives as potential NA inhibitors were studied by combination of molecular modeling techniques including 3D-QSAR, molecular docking, and molecular dynamics (MD) simulation. The results show that the best CoMFA (comparative molecular field analysis) model has q2 = 0.728 and r2 = 0.988, and the best CoMSIA (comparative molecular similarity indices analysis) model has q2 = 0.750 and r2 = 0.981, respectively. The built 3D-QSAR models show significant statistical quality and excellent predictive ability. Seven new NA inhibitors were designed and predicted. 20 ns of MD simulations were carried out and their binding free energies were calculated. Two designed compounds were selected to be synthesized and biologically evaluated by NA inhibition and virus inhibition assays. One compound (IC50 = 0.670 µM, SI > 149) exhibits excellent antiviral activity against A/WSN/33 H1N1, which is superior to the reference drug zanamivir (IC50 = 0.873 µM, SI > 115). The theoretical and experimental results may provide reference for development of new anti-influenza drugs.

Clinical effectiveness of four neuraminidase inhibitors (oseltamivir, zanamivir, laninamivir, and peramivir) for children with influenza A and B in the 2014-2015 to 2016-2017 influenza seasons in Japan.

The clinical effectiveness of four neuraminidase inhibitors (NAIs) (oseltamivir, zanamivir, laninamivir, and peramivir) for children aged 0 months to 18 years with influenza A and B were investigated in the 2014-2015 to 2016-2017 influenza seasons in Japan. A total of 1207 patients (747 with influenza A and 460 with influenza B) were enrolled. The Cox proportional-hazards model using all of the patients showed that the duration of fever after administration of the first dose of the NAI was shorter in older patients (hazard ratio = 1.06 per 1 year of age, p < 0.001) and that the duration of fever after administration of the first dose of the NAI was shorter in patients with influenza A infection than in patients with influenza B infection (hazard ratio = 2.21, p < 0.001). A logistic regression model showed that the number of biphasic fever episodes was 2.99-times greater for influenza B-infected patients than for influenza A-infected patients (p < 0.001). The number of biphasic fever episodes in influenza A- or B-infected patients aged 0-4 years was 2.89-times greater than that in patients aged 10-18 years (p = 0.010), and the number of episodes in influenza A- or B-infected patients aged 5-9 years was 2.13-times greater than that in patients aged 10-18 years (p = 0.012).

Neuraminidase inhibitor susceptibility profile of human influenza viruses during the 2016-2017 influenza season in Mainland China.

To understand the current situation of antiviral-resistance of influenza viruses to neuraminidase inhibitors (NAIs) in Mainland China, The antiviral-resistant surveillance data of the circulating influenza viruses in Mainland China during the 2016-2017 influenza season were analyzed. The total 3215 influenza viruses were studied to determine 50% inhibitory concentration (IC50) for oseltamivir and zanamivir using a fluorescence-based assay. Approximately 0.3% (n = 10) of viruses showed either highly reduced inhibition (HRI) or reduced inhibition (RI) against at least one NAI. The most common neuraminidase (NA) amino acid substitution was H275Y in A (H1N1)pdm09 virus, which confers HRI by oseltamivir. Two A (H1N1)pdm09 viruses contained a new NA amino acid substitution respectively, S110F and D151E, which confers RI by oseltamivir or/and zanamivir. Two B/Victoria-lineage viruses harbored a new NA amino acid substitution respectively, H134Q and S246P, which confers RI by zanamivir. One B/Victoria-lineage virus contained dual amino acid substitution NA P124T and V422I, which confers HRI by zanamivir. One B/Yamagata-lineage virus was a reassortant virus that haemagglutinin (HA) from B/Yamagata-lineage virus and NA from B/Victoria-lineage virus, defined as B/Yamagata-lineage virus confers RI by oseltamivir, but as B/Victoria-lineage virus confers normal inhibition by oseltamivir. All new substitutions that have not been reported before, the correlation of these substitutions and observed changes in IC50 should be further assessed. During the 2016-2017 influenza season in Mainland China the majority tested viruses were susceptible to oseltamivir and zanamivir. Hence, NAIs remain the recommended antiviral for treatment and prophylaxis of influenza virus infections.

Clinicians' attitude towards a placebo-controlled randomised clinical trial investigating the effect of neuraminidase inhibitors in adults hospitalised with influenza.

BACKGROUND: The value of neuraminidase inhibitors (NAIs) in reducing severe clinical outcomes from influenza is debated. A clinical trial to generate better evidence is desirable. However, it is unknown whether UK clinicians would support a placebo-controlled trial. A survey was conducted to determine the attitude of clinicians towards a clinical trial and their current practice in managing adults admitted to hospital with suspected influenza. METHODS: Senior clinicians (n = 50) across the UK actively involved in the care of patients hospitalised with severe respiratory infections and/or respiratory infection research were invited to participate in an on-line survey. Participants were asked their opinion on the evidence for benefit of NAIs in influenza, their current practice in relation to: a) testing for influenza; b) treating empirically with NAIs; and c) when influenza infection is virolologically confirmed, prescribing NAIs. RESULTS: Thirty-five (70%) of 50 clinicians completed the survey. Respondents were drawn mainly from infectious diseases, intensive care and respiratory medicine. Only 11 (31%) of 35 respondents agreed that NAIs are effective at reducing influenza mortality; 14 (40%) disagreed, 10 (28.6%) neither agreed nor disagreed. When managing adults admitted to non-ICU wards with a respiratory infection during an influenza season, 15 (51.7%) clinicians indicated they would usually perform a test for influenza in greater than 60% of patients but only 9 (31%) would treat empirically with NAIs in greater than 60% of patients. Few clinicians would either test or empirically treat patients presenting with other (non-respiratory infection related) diagnoses. If influenza infection is confirmed, 17 (64.5%) clinicians would prescribe NAIs in greater than 80% of patients with a respiratory infection treated on non-ICU wards Thirty-one (89%) clinicians agreed that a placebo-controlled clinical trial should be conducted and 29 (85%) would participate in such a trial. CONCLUSIONS: There is strong support from UK clinicians for a placebo-controlled trial of NAI treatment in adults hospitalised with suspected influenza. Current variation in medical opinion and clinical practice demonstrates collective equipoise, supporting ethical justification for a trial. Low use of NAIs in the UK suggests randomisation of treatment would not substantially divert patients towards placebo.

Droplet digital PCR to investigate quasi-species at codons 119 and 275 of the A(H1N1)pdm09 neuraminidase during zanamivir and oseltamivir therapies.

The H275Y and E119D neuraminidase (NA) mutations constitute important molecular markers of resistance to NA inhibitors in A(H1N1) pdm09 viruses. We used reverse transcriptase-droplet digital PCR amplification (RT-ddPCR) to analyze quasi-species at codons 275 and 119 of the NA in A(H1N1) pdm09 viruses recovered from an immuncompromised patient who received oseltamivir and zanamivir therapies. RT-ddPCR assays detected and quantified H275Y and E119D mutations with an efficiency that was comparable to that of high throughput sequencing (HiSeq 2500 Illumina, San Diego, CA) technology. With its sensitivity and reproducibility, RT-ddPCR could be a reliable method for accurate detection and quantification of major NAI-resistance mutations in clinical settings. J. Med. Virol. 89:737-741, 2017. © 2016 Wiley Periodicals, Inc.

Adverse events of prophylactic anti-influenza agents in medical staffs.

BACKGROUND: We undertook a survey to evaluate the compliance and the tolerability of oseltamivir and zanamivir when they were used as post-exposure prophylaxis among the medical staffs in the 2014-2015 seasons to understand a characteristic of adverse events caused by anti-influenza (flu) agents. MATERIALS AND METHODS: During the study period, 540 medical staffs received oseltamivir (75 mg twice a day for 5 days) or zanamivir (twice a day for 5 days) as post-exposure prophylaxis of influenza, respectively. RESULTS: Four hundred eleven medical staffs of 540 medical staffs (76.1%) provided responses to questionnaire investigations. The adverse events caused by oseltamivir were reported by 86 of 382 medical staffs (22.5%). The most frequent adverse events were gastrointestinal adverse events (13.4%), followed by systemic and local diseases (11.8%), diseases of the nervous system (7.9%) and neuropsychiatric adverse events (0.5%). On the other hand, adverse events caused by zanamivir were reported by one (3.4%) of 29 medical staffs. CONCLUSION: Our survey revealed that 22.5% subjects experienced any adverse events due to oseltamivir. And the regimen showed low compliance than we expected. On the other hands, zanamivir showed high adherence with lower incidence of adverse events.

In vitro neuraminidase inhibitory concentration (IC50) of four neuraminidase inhibitors in the Japanese 2015-16 season: Comparison with the 2010-11 to 2014-15 seasons.

To assess the extent of susceptibility to the four most commonly used neuraminidase inhibitors (NAIs) in the viruses epidemic in the 2015-2016 influenza season in Japan, we measured the 50% inhibitory concentration (IC50) of NAIs for influenza virus isolates and compared them with the results from the 2010-11 to 2014-15 influenza seasons. Viral isolation was done with specimens obtained prior to treatment, and the type and subtype of influenza was determined by RT-PCR using type- and subtype-specific primers. The IC50 was determined by a neuraminidase inhibition assay using a fluorescent substrate. Influenza viruses were isolated: 210 influenza A(H1N1)pdm09 (67.3%), 20 A(H3N2) (6.4%), and 82 B (26.3%), and for the Victoria and Yamagata lineages the numbers were 53 (64.6%) and 28 (34.1%), respectively, with one unknown. Two A(H1N1)pdm09 isolates showed a high IC50 for oseltamivir (130 and 150 nM). No isolate showed a very high IC50 for A(H3N2) or B. The ratios of geometric mean IC50 of the 2015-2016 influenza season to those of the 2010-2011 to 2014-2015 influenza seasons ranged from 0.62 to 1.78 for A(H1N1) pdm09. The range was 0.73-1.35 for A(H3N2) and 0.48-1.12 for B. No significant trend of increase or decrease in IC50 was found for any of the four NAIs. Although some isolates showed highly reduced sensitivity to oseltamivir among the A(H1N1)pdm09 isolates, the currently epidemic influenza A(H1N1)pdm09, A(H3N2), and B viruses are susceptible to all four NAIs, with no trend toward decreased sensitivity.

Different Inhibitory Potencies of Oseltamivir Carboxylate, Zanamivir, and Several Tannins on Bacterial and Viral Neuraminidases as Assessed in a Cell-Free Fluorescence-Based Enzyme Inhibition Assay.

Neuraminidaseis a key enzyme in the life cycle of influenza viruses and is present in some bacterial pathogens. We here assess the inhibitory potency of plant tannins versus clinically used inhibitors on both a viral and a bacterial model neuraminidase by applying the 2'-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid (MUNANA)-based activity assay. A range of flavan-3-ols, ellagitannins and chemically defined proanthocyanidin fractions was evaluated in comparison to oseltamivir carboxylate and zanamivir for their inhibitory activities against viral influenza A (H1N1) and bacterial Vibrio cholerae neuraminidase (VCNA). Compared to the positive controls, all tested polyphenols displayed a weak inhibition of the viral enzyme but similar or even higher potency on the bacterial neuraminidase. Structure-activity relationship analyses revealed the presence of galloyl groups and the hydroxylation pattern of the flavan skeleton to be crucial for inhibitory activity. The combination of zanamivir and EPs® 7630 (root extract of Pelargonium sidoides) showed synergistic inhibitory effects on the bacterial neuraminidase. Co-crystal structures of VCNA with oseltamivir carboxylate and zanamivir provided insight into bacterial versus viral enzyme-inhibitor interactions. The current data clearly indicate that inhibitor potency strongly depends on the biological origin of the enzyme and that results are not readily transferable. The therapeutic relevance of our findings is briefly discussed.

Development of neuraminidase detection using gold nanoparticles boron-doped diamond electrodes.

Gold nanoparticles-modified boron-doped diamond (AuNPs-BDD) electrodes, which were prepared with a self-assembly deposition of AuNPs at amine-terminated boron-doped diamond, were examined for voltammetric detection of neuraminidase (NA). The detection method was performed based on the difference of electrochemical responses of zanamivir at gold surface before and after the reaction with NA in phosphate buffer solution (PBS, pH 5.5). A linear calibration curve for zanamivir in 0.1 M PBS in the absence of NA was achieved in the concentration range of 1 × 10(-6) to 1 × 10(-5) M (R(2) = 0.99) with an estimated limit of detection (LOD) of 2.29 × 10(-6) M. Furthermore, using its reaction with 1.00 × 10(-5) M zanamivir, a linear calibration curve of NA can be obtained in the concentration range of 0-12 mU (R(2) = 0.99) with an estimated LOD of 0.12 mU. High reproducibility was shown with a relative standard deviation (RSD) of 1.14% (n = 30). These performances could be maintained when the detection was performed in mucin matrix. Comparison performed using gold-modified BDD (Au-BDD) electrodes suggested that the good performance of the detection method is due to the stability of the gold particles position at the BDD surface.

Emergence of Multidrug-Resistant Influenza A(H1N1)pdm09 Virus Variants in an Immunocompromised Child Treated With Oseltamivir and Zanamivir.

Prolonged treatment of an immunocompromised child with oseltamivir and zanamivir for A(H1N1)pdm09 virus infection led to the emergence of viruses carrying H275Y and/or E119G in the neuraminidase (NA). When phenotypically evaluated by NA inhibition, the dual H275Y-E119G substitution caused highly reduced inhibition by 4 NA inhibitors: oseltamivir, zanamivir, peramivir, and laninamivir.