Role of Spin-Orbit Coupling in High-Order Harmonic Generation Revealed by Supercycle Rydberg Trajectories

High-harmonic generation is typically thought of as a sub-laser-cycle process, with the electron's excursion in the continuum lasting a fraction of the optical cycle. However, it was recently suggested that long-lived Rydberg states can play a particularly important role in high harmonic generation by atoms driven by the combination of the counterrotating circularly polarized fundamental light field and its second harmonic. Here we report direct experimental evidence of very long and stable Rydberg trajectories contributing to high-harmonic generation in such fields. We track their dynamics inside the laser pulse using the spin-orbit evolution in the ionic core, utilizing the spin-orbit Larmor clock. We confirm their effect on harmonic emission both via microscopic simulations and by showing how this radiation can lead to a well-collimated macroscopic far-field signal. Our observations contrast sharply with the general view that long-lived Rydberg orbits should generate negligible contribution to the macroscopic far-field high harmonic response of the medium.

Concordance de la détection des virus respiratoires sur écouvillonnage nasopharyngé et lavage broncho-alvéolaire chez l'adulte admis pour une suspicion de pneumonie

Introduction

A ce jour, peu de données sont disponibles sur la concordance de la détection des virus respiratoires (en dehors du SARS-CoV2) entre le prélèvement nasopharyngé (NP) et le lavage broncho-alvéolaire (LBA) chez l'adulte. L'objectif de cette étude était de décrire la concordance de leurs résultats.

Matériels et méthodes

Une analyse rétrospective monocentrique a été réalisée à l'aide des données de 276 adultes suspects de pneumonie et testés par PCR multiplex dans le NP et le LBA à 24 heures d'intervalle.

Résultats

Les patients étaient majoritairement des hommes (65 %), avec un âge médian de 60 ans[IQR : 50,9-67,8]. 169 patients (61 %) ont été admis en réanimation Nous avons détecté au moins un virus respiratoire dans 95 NP (34 %) et dans 80 BAL (29 %). Comparé au LBA, le NP avait une sensibilité de 71,6 % et une spécificité de 93,4 % et un coefficient Kappa de 0,67. Le même agent pathogène ou combinaison d'agents pathogènes a été observé chez 84 % des patients positifs à la fois sur le NP et le LBA. La grippe B, le parainfluenza, les coronavirus HKU1, NL63, 229E présentaient la concordance la plus élevée (100 %) entre le NP et la LBA, tandis que le coronavirus OC43 et le rhinovirus présentaient la concordance la plus faible (33 % et 67 %, respectivement).Nous avons observé que les patients atteints d'une maladie respiratoire chronique ont une plus faible concordance entre le NP et LBA avec un OR ajusté à 0,5, IC 95 % (0,25-0,97), p = 0,043.

Conclusion

Dans ce travai, Il y a une bonne concordance entre le NP et le LBA dans la détection des virus respiratoires chez les patients consultant avec une suspicion de pneumonie.

Néanmoins, ces données encouragent toujours à réaliser un LBA lorsque cela est possible afin d'obtenir un diagnostic étiologique plus précis.

Aucun lien d'intérêt

Spectral filtering of high-order harmonics via optics-free focusing

Controlling the wavefront of an extreme ultraviolet (XUV) high-order harmonic beam during the generation process offers the capability of modifying the beam properties without resorting to any XUV optics. By characterizing the XUV intensity profile and wavefront, we quantitatively retrieve both the size and the position of the waist of each harmonic generated in an argon jet. We show that optics-free focusing can occur under specific generating conditions leading to XUV focii of micrometer size. We also demonstrate that each focus is located at distinct longitudinal positions. Using this remarkable XUV wavefront control combined with near focus spatial selection, we experimentally demonstrate efficient and adjustable spectral filtering of the XUV beam, along with a strong rejection of the fundamental beam, without using any XUV optics. The experimental results are compared with simulations providing the impact of the filtering on the temporal profile of the XUV field. It shows that the attosecond structure is preserved and that the beam is more homogeneous after the filtering, thereby reducing the longitudinal focii shift. This is a major step to achieve high XUV intensity and probing ultrafast processes with an improved resolution.

Impact de la pandémie de COVID-19 sur les populations sans domicile fixe : résultats d’une cohorte fermée rétrospective (mars–mai 2020)

Introduction

Les populations de sans domicile fixe ont un taux de mortalité supérieur à celui de la population générale. Ceci est en partie en lien avec des maladies chroniques non suivis, des problèmes d’addiction ainsi qu’une exposition plus forte aux maladies transmissibles, en particulier respiratoires. Nous avons réalisé une étude pour évaluer les taux d’attaque, d’hospitalisation et de mortalité liés à l’infection par le SARS-CoV-2 dans une population de résidents de centres d’hébergement pour sans-abri et du personnel à leur contact.

Matériels et méthodes

Une étude sérologique rétrospective a été réalisée sur l’ensemble des résidents et des membres du personnel de trois centres d’hébergement pour sans-abri entre mars et mai 2020 : 2 centres de lits halte soins santé (LHSS) et un dortoir de femmes. Nous avons inclus tous les adultes présents dans les centres d’hébergement ou décédés d’une infection avérée par le SARS-CoV-2. Les IgG anti-SARS-CoV-2 étaient détectés par le test ELISA « SARS-CoV-2 IgG Architect (Abbott) ». Un cas confirmé de SARS-CoV-2 était défini comme tout participant présentant une PCR ou une sérologie positive. Des sérologies de contrôle ont été prélevées quatre mois après la première sérologie positive.

Résultats

Nous avons inclus 100 résidents et 83 membres du personnel. Le taux de SARS-CoV-2 confirmé par PCR ou sérologie était de 72/100 (72,0 %) pour les résidents et de 17/83 (20,5 %) pour le personnel. Le taux d’hospitalisation chez les résidents était de 17/72 (25 %) et le taux de décès de 4/72 (5,6 %). Toutes les hospitalisations sauf une et tous les décès sont survenus chez des résidents des LHSS. Trente-quatre sur 68 (50 %) des résidents des LHSS présentaient au moins deux facteurs de risque de forme grave d’infection par le SARS-CoV-2. Les femmes hébergées dans le dortoir étaient plus jeunes, présentaient moins de comorbidité, avaient le taux d’attaque le plus élevé (90,6 %) et une morbidité-mortalité quasi nulle. Cinquante-deux sur 80 (63,4 %) des personnes ayant une première sérologie positive ont eu une sérologie de contrôle à 4 mois de la première sérologie et 8 mois environ de leur infection. Parmi eux, 44 (84,6 %) avaient conservé des sérologies positives.

Conclusion

Le taux d’attaque du SARS-CoV-2 était extrêmement élevé chez les résidents des centres d’hébergement pour sans-abri par rapport à la population générale. Le risque d’infection grave par le SARS-CoV-2 était fortement associé à la présence de comorbidités à un plus jeune âge. Cette population à risqué doit être considérée comme prioritaire dans les campagnes de vaccination dans l’accès aux logements individuels pour les plus vulnérables.

Émergence de variants E484 K suite à une monothérapie bamlanivimab chez des patients COVID-19 à haut risque d’évolution vers une forme sévère

Introduction

En France, une Autorisation d’Utilisation Temporaire de cohorte (ATUc) a été délivrée le 27/02/2021 pour l’utilisation du bamlanivimab en monothérapie dans le traitement précoce (< 5 jours du début des symptômes) de patients adultes avec un COVID-19 léger à modéré confirmé par PCR et à haut risque d’évolution vers une forme sévère. Les patients concernés étaient les patients de > 80 ans ou les patients de < 80 ans immunodéprimés (transplantation, chimiothérapie, traitement immunosuppresseur). Le risque d’émergence de variants potentiellement résistants à un monothérapie par anticorps monoclonal anti-Spike, en particulier les variants E484 K, avait été pris en compte lors de l’ATUc. Cependant, le bénéfice potentiel de ces traitements chez les patients à haut risque a été considéré comme supérieur au risque. Ici nous décrivons 6 patients ayant reçu de ce traitement, leur évolution et l’émergence de mutations de résistance sous pression de sélection.

Matériels et méthodes

Il s’agit d’une étude unicentrique en centre hospitalier universitaire. Le bamlanivimab a été administré à une dose unique de 700 mg en injection IV d’une heure chez 6 patients qui ont accepté d’utiliser le traitement dans le cadre de l’ATUc. Le suivi virologique des patients a consisté en un test RT-qPCR itératif réalisé le jour de la perfusion ou la veille, à J3 ± 1, à J5 ± 1, à J7 ± 1 puis tous les 3 jours jusqu’à ce que la PCR soit négative. La sélection de mutation de résistance a été vérifiée par séquençage du génome complet du SARS-CoV-2 chez tous les patients.

Résultats

Les six hommes traités avaient un âge médian de 65 ans (extrêmes 35-97), plus de 3 comorbidités à haut risque d’évolution vers une forme sévère et 5 étaient infectés par un variant UK (N501Y.V1, B.1.1.7). Le traitement a été administré dans les 4 jours suivant l’apparition des symptômes (médiane 2 jours). Les 6 patients ont eu une évolution clinique favorable, deux ont eu besoin d’oxygène au débit maximal de 4 L/min. Aucun patient n’a eu besoin d’oxygénothérapie haut débit, d’une ventilation non invasive ou d’une ventilation invasive. À J20 après l’administration, un seul présentait une PCR nasopharyngée négative et 5 présentaient l’apparition d’une mutation E484 K à différents moments après l’administration (J6, J7, J12, J14 et J26).

Conclusion

Chez ces patients à très haut risque d’évolution vers une forme sévère, la sélection de la mutation E484 K après administration de bamlanivimab en monothérapie était très fréquente et bien plus importante qu’observée dans les premiers essais cliniques. Ceci peut être expliqué en partie par l’infection par un variant UK pour 5/6 patients décrits ici. L’émergence de résistance lors des bithérapies devra être suivi attentivement, notamment avec l’émergence des nouveaux variants.

High-order parametric generation of coherent XUV radiation

Extreme ultraviolet (XUV) radiation finds numerous applications in spectroscopy. When the XUV light is generated via high-order harmonic generation (HHG), it may be produced in the form of attosecond pulses, allowing access to unprecedented ultrafast phenomena. However, the HHG efficiency remains limited. Here we present an observation of a new regime of coherent XUV emission which has a potential to provide higher XUV intensity, vital for applications. We explain the process by high-order parametric generation, involving the combined emission of THz and XUV photons, where the phase matching is very robust against ionization. This introduces a way to use higher-energy driving pulses, thus generating more XUV photons.

Microelimination or Not? The Changing Epidemiology of Human Immunodeficiency Virus-Hepatitis C Virus Coinfection in France 2012–2018

Background

The arrival of highly effective, well-tolerated, direct-acting antiviral agents (DAA) led to a dramatic decrease in hepatitis C virus (HCV) prevalence. Human immunodeficiency virus (HIV)-HCV–coinfected patients are deemed a priority population for HCV elimination, while a rise in recently acquired HCV infections in men who have sex with men (MSM) has been described. We describe the variations in HIV-HCV epidemiology in the French Dat’AIDS cohort.

Methods

This was a retrospective analysis of a prospective cohort of persons living with HIV (PLWH) from 2012 to 2018. We determined HCV prevalence, HCV incidence, proportion of viremic patients, treatment uptake, and mortality rate in the full cohort and by HIV risk factors.

Results

From 2012 to 2018, 50 861 PLWH with a known HCV status were followed up. During the period, HCV prevalence decreased from 15.4% to 13.5%. HCV prevalence among new HIV cases increased from 1.9% to 3.5% in MSM but remained stable in other groups. Recently acquired HCV incidence increased from 0.36/100 person-years to 1.25/100 person-years in MSM. The proportion of viremic patients decreased from 67.0% to 8.9%. MSM became the first group of viremic patients in 2018 (37.9%). Recently acquired hepatitis represented 59.2% of viremic MSM in 2018. DAA treatment uptake increased from 11.4% to 61.5%. More treatments were initiated in MSM in 2018 (41.2%) than in intravenous drug users (35.6%). In MSM, treatment at the acute phase represented 30.0% of treatments in 2018.

Conclusions

A major shift in HCV epidemiology was observed in PLWH in France from 2012 to 2018, leading to a unique situation in which the major group of HCV transmission in 2018 was MSM.

Clinical Trials Registration. NCT02898987.

Absolute gas density profiling in high-order harmonic generation: erratum

In this erratum, we correct two numerical errors due to conversion mistakes from our previous published manuscript [Opt. Express 26, 6001 (2018)]. In the original manuscript, the two errors compensated each other such that the conclusions remain perfectly unchanged.

Aurore: A platform for ultrafast sciences

We present the Aurore platform for ultrafast sciences. This platform is based on a unique 20 W, 1 kHz, 26 fs Ti:sapphire laser system designed for reliable operation and high intensity temporal contrast. The specific design ensures the high stability in terms of pulse duration, energy, and beam pointing necessary for extended experimental campaigns. The laser supplies 5 different beamlines, all dedicated to a specific field: attosecond science (Aurore 1), ultrafast phase transitions in solids (Aurore 2 and 3), ultrafast luminescence in solids (Aurore 4), and femtochemistry (Aurore 5). The technical specifications of these five beamlines are described in detail, and examples of the recent results are given.

Management of oral antiretroviral administration in patients with swallowing disorders or with an enteral feeding tube

HIV infection has evolved into a chronic disease with comorbidities since the combination antiretroviral therapy era. Complications still occur and patients may need to be admitted to an intensive care unit. Acute respiratory failure is the first cause of these admissions, questioning the administration of solid oral dosage formulations. This issue is also observed in geriatric units where the prevalence of dysphagia is high and underestimated. The problem of antiretroviral administration is critical: altered solid oral dosage formulations and/or administration via enteral feeding tubes are sometimes the only option. The aim is to help manage antiretroviral treatment in unconscious or intubated patients and those with swallowing disorders who are hospitalized in intensive care units or geriatric units. This review provides information on the main antiretroviral regimens and on practical and legal aspects of manipulating solid oral dosage formulations and administration via enteral feeding tubes. Alternatives to the solid formulation are available for most of the 27 oral antiretrovirals available, or manufacturers provide recommendations for patients who are unable to swallow. Manipulation of solid oral dosage formulations such as crushing tablets or opening capsules and administration via feeding tubes are frequently reported but should be the last option for safety and liability issues. Before any off-label administration of a drug, physicians should consider alternatives to the solid oral dosage formulation and check whether the drug can be altered. Therapeutic monitoring is important in this particular setting as the pharmacokinetic profile of drugs is difficult to predict.

Emerging resistance mutations in PI-naive patients failing an atazanavir-based regimen (ANRS multicentre observational study)

Background

Atazanavir is a PI widely used as a third agent in combination ART. We aimed to determine the prevalence and the patterns of resistance in PI-naive patients failing on an atazanavir-based regimen.

Methods

We analysed patients failing on an atazanavir-containing regimen used as a first line of PI therapy. We compared the sequences of reverse transcriptase and protease before the introduction of atazanavir and at failure [two consecutive viral loads (VLs) >50 copies/mL]. Resistance was defined according to the 2014 Agence Nationale de Recherche sur le SIDA et les Hépatites Virales (ANRS) algorithm.

Results

Among the 113 patients, atazanavir was used in the first regimen in 71 (62.8%) patients and in the first line of a PI-based regimen in 42 (37.2%). Atazanavir was boosted with ritonavir in 95 (84.1%) patients and combined with tenofovir/emtricitabine or lamivudine (n = 81) and abacavir/lamivudine or emtricitabine (n = 22). At failure, median VL was 3.05 log10 copies/mL and the median CD4+ T cell count was 436 cells/mm3. The median time on atazanavir was 21.2 months. At failure, viruses were considered resistant to atazanavir in four patients (3.5%) with the selection of the following major atazanavir-associated mutations: I50L (n = 1), I84V (n = 2) and N88S (n = 1). Other emergent PI mutations were L10V, G16E, K20I/R, L33F, M36I/L, M46I/L, G48V, F53L, I54L, D60E, I62V, A71T/V, V82I/T, L90M and I93L/M. Emergent NRTI substitutions were detected in 21 patients: M41L (n = 2), D67N (n = 3), K70R (n = 1), L74I/V (n = 3), M184V/I (n = 16), L210W (n = 1), T215Y/F (n = 3) and K219Q/E (n = 2).

Conclusions

Resistance to atazanavir is rare in patients failing the first line of an atazanavir-based regimen according to the ANRS. Emergent NRTI resistance-associated mutations were reported in 18% of patients.

Prevalence and clinical impact of minority resistant variants in patients failing an integrase inhibitor-based regimen by ultra-deep sequencing

Background

Integrase strand transfer inhibitors (INSTIs) are recommended by international guidelines as first-line therapy in antiretroviral-naive and -experienced HIV-1-infected patients.

Objectives

This study aimed at evaluating the prevalence at failure of INSTI-resistant variants and the impact of baseline minority resistant variants (MiRVs) on the virological response to an INSTI-based regimen.

Methods

Samples at failure of 134 patients failing a raltegravir-containing (n = 65), an elvitegravir-containing (n = 20) or a dolutegravir-containing (n = 49) regimen were sequenced by Sanger sequencing and ultra-deep sequencing (UDS). Baseline samples of patients with virological failure (VF) (n = 34) and of those with virological success (VS) (n = 31) under INSTI treatment were sequenced by UDS. Data were analysed using the SmartGene platform, and resistance was interpreted according to the ANRS algorithm version 27.

Results

At failure, the prevalence of at least one INSTI-resistant variant was 39.6% by Sanger sequencing and 57.5% by UDS, changing the interpretation of resistance in 17/134 (13%) patients. Among 53 patients harbouring at least one resistance mutation detected by both techniques, the most dominant INSTI resistance mutations were N155H (45%), Q148H/K/R (23%), T97A (19%) and Y143C (11%). There was no difference in prevalence of baseline MiRVs between patients with VF and those with VS. MiRVs found at baseline in patients with VF were not detected at failure either in majority or minority mutations.

Conclusions

UDS is more sensitive than Sanger sequencing at detecting INSTI MiRVs at treatment failure. The presence of MiRVs at failure could be important to the decision to switch to other INSTIs. However, there was no association between the presence of baseline MiRVs and the response to INSTI-based therapies in our study.

Cascaded harmonic generation from a fiber laser: a milliwatt XUV source

Recent progresses in femtosecond ytterbium-doped fiber laser technology are opening new perspectives in strong field physics and attosecond science. High-order harmonic generation from these systems is particularly interesting because it provides high flux beams of ultrashort extreme ultraviolet radiation. A great deal of effort has been devoted to optimize the macroscopic generation parameters. Here we investigate the possibility of enhancing the single-atom response by producing high-order harmonics from the second, third and fourth harmonics of a turnkey 50 W, 166 kHz femtosecond Yb-fiber laser providing 135 fs pulses at 1030 nm. We show that the harmonic efficiency is optimal when the process is driven by the third harmonic, producing 6.6 ± 1.3 × 10¹⁴ photons/s at 18 eV in argon, which corresponds to 1.9 ± 0.4 mW average power.

Prevalence of human papillomavirus, human immunodeficiency virus and other sexually transmitted infections among female sex workers in Togo: a national cross-sectional survey

OBJECTIVES

Sub-Saharan Africa is a region with high incidence of both human immunodeficiency virus (HIV) and cervical cancer. We conducted the first national study in Togo to assess prevalence of human papillomavirus (HPV), HIV and other sexually transmitted infections (STIs) among female sex workers (FSW).

METHODS

A multicentric cross-sectional study was conducted among FSW recruited in hot spots (clubs, streets) in four Togolese cities. HPV and STIs were tested from cervical and anal swabs. HIV and syphilis were screened with rapid tests.

RESULTS

In all, 310 FSW were recruited; HIV and cervical high-risk HPV (hrHPV) prevalence were 10.6% (33/310) and 32.9% (102/310), respectively. The most frequent hrHPV types were HPV58 (13.6%, 19/140), HPV35 (12.9%, 18/140), HPV31 (12.1%, 17/140) and HPV16 (10.7%, 15/140). Prevalence of hrHPV and multiple hrHPV infections showed higher rates in HIV-positive than in HIV-negative FSW (48.5% versus 31.0%, p 0.04 and 21.2% versus 9.0%, p 0.03; respectively). Prevalence of hrHPV was higher in cervical than anal swabs (34.1% versus 20.7%, p 0.0004). High-risk HPV anal infections were more frequent among HIV-positive than HIV-negative FSW (51.9% versus 17.3%, p 2 × 10^-5). Concomitant anal and cervical hrHPV infections were present in 43.2% (41/95) of hrHPV-positive FSW. Overall prevalence in the cervix of Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium and Trichomonas vaginalis were 4.2%, 6.1%, 5.5% and 6.5%, respectively.

CONCLUSIONS

This first African study on paired cervical and anal samples showed a high prevalence of genital HPV infections with a rather high rate of concomitant HPV infections but low type concordance. We report an unusual distribution of hrHPV types. These findings highlight the critical need for implementation of a national HPV vaccination strategy.

Optics-less focusing of XUV high-order harmonics

By experimentally studying high-order harmonic beams generated in gases, we show how the spatial characteristics of these ultrashort extreme-ultraviolet (XUV) beams can be finely controlled when a single fundamental beam generates harmonics in a thin gas medium. We demonstrate that these XUV beams can be emitted as converging beams and thereby get focused after generation. We study this optics-less focusing using a spatially chirped beam that acts as a probe located inside the harmonic generation medium. We analyze the XUV beam evolution with an analytical model and obtain very good agreement with experimental measurements. The XUV foci sizes and positions vary strongly with the harmonic order, and the XUV waist can be located at arbitrarily large distances from the generating medium. We discuss how intense XUV fields can be obtained with optics-less focusing and how the order-dependent XUV beam characteristics are compatible with broadband XUV irradiation and attosecond science.

Wavelength scaling of terahertz pulse energies delivered by two-color air plasmas

We address the long-standing problem of anomalous growth observed in the terahertz (THz) energy yield from air plasmas created by two-color laser pulses, as the fundamental wavelength λ₀ is increased. Using two distinct optical parametric amplifiers (OPAs), we report THz energies scaling like λ0α with large exponents 5.6≤α≤14.3, which departs from the growth in λ02 expected from photocurrent theory. By means of comprehensive 3D simulations, we demonstrate that the changes in the laser beam size, pulse duration, and phase-matching conditions in the second-harmonic generation process when tuning the OPA's carrier wavelength can lead to these high scaling powers. The value of the phase angle between the two colors reached at the exit of the doubling crystal turns out to be crucial and even explains non-monotonic behaviors in the measurements.

Real-time determination of enantiomeric and isomeric content using photoelectron elliptical dichroism

The fast and accurate analysis of chiral chemical mixtures is crucial for many applications but remains challenging. Here we use elliptically-polarized femtosecond laser pulses at high repetition rates to photoionize chiral molecules. The 3D photoelectron angular distribution produced provides molecular fingerprints, showing a strong forward-backward asymmetry which depends sensitively on the molecular structure and degree of ellipticity. Continuously scanning the laser ellipticity and analyzing the evolution of the rich, multi-dimensional molecular signatures allows us to observe real-time changes in the chemical and chiral content present with unprecedented speed and accuracy. We measure the enantiomeric excess of a compound with an accuracy of 0.4% in 10 min acquisition time, and follow the evolution of a mixture with an accuracy of 5% with a temporal resolution of 3 s. This method is even able to distinguish isomers, which cannot be easily distinguished by mass-spectrometry.

Comparison of 48-week efficacies of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide and nucleoside/nucleotide reverse transcriptase inhibitor-sparing regimens: a systematic review and network meta-analysis

OBJECTIVES

To compare nucleoside/nucleotide reverse transcriptase inhibitor (NRTI)-sparing regimens with tenofovir alafenamide (TAF)-based combinations in HIV-1-infected adults, we performed a network meta-analysis (NMA) to provide estimates of relative efficacy for these two regimens.

METHODS

A systematic literature review (SLR) was performed to identify phase 3/4 randomized controlled clinical trials evaluating the efficacy of commonly used combination antiretroviral therapy (cART) including an NRTI backbone or that of commonly used NRTI-sparing regimens. A Bayesian random-effect model was used to compare virological suppression rates at 48 weeks for NRTI-sparing regimens and elvitegravir/cobicistat/emtricitabine/TAF (E/C/F/TAF).

RESULTS

Twenty-three studies in treatment-naïve patients identified by the SLR were included in the NMA, including four studies assessing NRTI-sparing regimens. In treatment-naïve patients, the probability of achieving virological suppression at 48 weeks was between 40% and 60% higher with E/C/F/TAF than with NRTI-sparing strategies. The credible interval vs. darunavir/ritonavir (DVR/r) + raltegravir (RAL) and LPV/r monotherapy did not include 1. In the subgroup of naïve patients with viral load < 100 000 HIV-1 RNA copies/mL, a credible difference was found between NRTI-sparing treatments and E/C/F/TAF. Studies in treatment-experienced patients were too heterogeneous to allow for an NMA.

CONCLUSIONS

The NMA results suggest that E/C/F/TAF represents a more effective option than NRTI-sparing regimens in terms of 48-week efficacy in treatment-naïve patients. Furthermore, TAF pharmacological properties, as well as tolerability results in clinical studies, suggest a safety profile similar to that of NRTI-sparing regimens. Thus, the E/C/F/TAF combination might represent a more appropriate option than NRTI-sparing regimens for initiation of antiretroviral therapy in treatment-naïve HIV-infected patients.

HIV-1 non-group M phenotypic susceptibility to integrase strand transfer inhibitors

Objectives

To determine natural phenotypic susceptibility of non-group M HIV-1 to integrase strand transfer inhibitors (INSTIs) in a large panel of 39 clinical strains from groups O, N and P and to identify genotypic polymorphisms according to susceptibility levels.

Methods

Susceptibility to raltegravir, elvitegravir and dolutegravir was evaluated in 36 HIV-1/O, 2 HIV-1/N and 1 HIV-1/P strains plus an HIV-1/M reference strain. IC50 values were determined after 3 days, and fold changes (FCs) were calculated relative to the HIV-1/M strain. Genotypic polymorphism was determined by amplification of codons 19-263 of the integrase; the natural occurrence of resistance-associated mutations was analysed using the main resistance algorithms and the IAS-USA list. VESPA analysis of the strain sequences was used to determine a signature pattern associated with higher FC.

Results

Similar IC50 results were observed for the three drugs. Based on the value for the HIV-1/M reference strain, the data showed FC values <2.5 for raltegravir and dolutegravir, whereas the distribution for elvitegravir was heterogeneous, with FC > 10 for six strains (15%). Analysis of the non-M integrase sequences showed a high level of polymorphism without a major genotypic impact; it also revealed mutations that may be associated with the highest FC values obtained for elvitegravir.

Conclusions

Our phenotypic data showed that non-M strains are globally susceptible to the three currently used INSTIs, but the impact of the high FC values observed for some strains with elvitegravir needs to be explored. Clinical data are now needed to confirm these phenotypic results.

Prevalence of HIV-1 drug resistance in treated patients with viral load >50 copies/mL: a 2014 French nationwide study

Background

Surveillance of HIV-1 resistance in treated patients with a detectable viral load (VL) is important to monitor, in order to assess the risk of spread of resistant viruses and to determine the proportion of patients who need new antiretroviral drugs with minimal cross-resistance.

Methods

The HIV-1 protease and reverse transcriptase (RT) and integrase genes were sequenced in plasma samples from 782 consecutive patients on failing antiretroviral regimens, seen in 37 specialized centres in 2014. The genotyping results were interpreted using the ANRS v24 algorithm. Prevalence rates were compared with those obtained during a similar survey conducted in 2009.

Results

The protease and RT sequences were obtained in 566 patients, and the integrase sequence in 382 patients. Sequencing was successful in 60%, 78%, 78% and 87% of patients with VLs of 51-200, 201-500, 501-1000 and >1000 copies/mL, respectively. Resistance to at least one antiretroviral drug was detected in 56.3% of samples. Respectively, 3.9%, 8.7%, 1.5% and 3.4% of patients harboured viruses that were resistant to any NRTI, NNRTI, PI and integrase inhibitor (INI). Resistance rates were lower in 2014 than in 2009. Resistance was detected in 48.5% of samples from patients with a VL between 51 and 200 copies/mL.

Conclusion

In France in 2014, 90.0% of patients in AIDS care centres were receiving antiretroviral drugs and 12.0% of them had VLs >50 copies/mL. Therefore, this study suggests that 6.7% of treated patients in France might transmit resistant strains. Resistance testing may be warranted in all treated patients with VL > 50 copies/mL.

Disparities in HIV-1 transmitted drug resistance detected by ultradeep sequencing between men who have sex with men and heterosexual populations

OBJECTIVES

Transmitted drug resistance (TDR) can impair the response to first-line antiretroviral therapy. In treatment-naïve patients chronically infected with HIV type 1 (HIV-1), it was previously shown through Sanger sequencing that TDR was more common in men who have sex with men (MSM) than in other transmission risk groups. We aimed to compare two HIV-1 transmission groups in terms of the presence of TDR mutations.

METHODS

We investigated, through Sanger sequencing and ultradeep sequencing (UDS), the presence of resistance mutations, both in majority (> 20%) and in minority (1-20%) proportions, in 70 treatment-naïve MSM and 70 treatment-naïve heterosexual patients who recently screened positive for HIV-1.

RESULTS

The global prevalence of TDR was not significantly different between the two groups, either by Sanger or by UDS. Nevertheless, a higher frequency of nucleoside reverse transcriptase inhibitor TDR was observed among heterosexual patients (P = 0.04). There was also a trend for a higher frequency of TDR among MSM infected with HIV-1 subtype B compared with MSM infected with HIV-1 non-B subtypes (P = 0.06).

CONCLUSIONS

Ultradeep sequencing UDS allowed sensitive monitoring of TDR, and highlighted some disparities between transmission groups.

Role of Excited States In High-order Harmonic Generation

We investigate the role of excited states in high-order harmonic generation by studying the spectral, spatial, and temporal characteristics of the radiation produced near the ionization threshold of argon by few-cycle laser pulses. We show that the population of excited states can lead either to direct extreme ultraviolet emission through free induction decay or to the generation of high-order harmonics through ionization from these states and recombination to the ground state. By using the attosecond lighthouse technique, we demonstrate that the high-harmonic emission from excited states is temporally delayed by a few femtoseconds compared to the usual harmonics, leading to a strong nonadiabatic spectral redshift.

In vitro susceptibility to mecillinam of Escherichia coli strains isolated from the urine of pregnant women

OBJECTIVES

Pivmecillinam is a safe beta-lactam for use in pregnancy. It has been widely used for the treatment of lower urinary tract infections (UTIs) in the Nordic countries where its efficacy, minor impact on the microbiota, and low level of resistance among the Escherichia coli strains have been proven. However, susceptibility data related to E. coli involved in asymptomatic bacteriuria and lower UTIs in pregnant women is lacking. We aimed to support the 2015 recommendations issued by the French Infectious Diseases Society (SPILF) on gestational UTI, with a particular focus on pivmecillinam.

MATERIAL AND METHODS

Antimicrobial susceptibility testing was performed by 12 hospitals with a maternity department on 235 E. coli strains isolated from the urine of pregnant women. Susceptibility to mecillinam was tested by disk diffusion method using the 2015 recommendations of the antibiogram committee of the French microbiology society (CA-SFM).

RESULTS

Global susceptibility to mecillinam was 86.4%. Susceptibility to mecillinam was 96.5% for strains susceptible to amoxicillin-clavulanic acid and 38.7% for resistant strains. All six extended-spectrum beta-lactamase-producing E. coli strains were susceptible to mecillinam.

CONCLUSION

Given the efficacy and safety of pivmecillinam during pregnancy, it may be used for the documented treatment of asymptomatic bacteriuria and acute cystitis in pregnant women. It also represents an alternative for the treatment of multidrug-resistant bacterial infections.

Factors associated with virological response to a switch regimen containing maraviroc for antiretroviral-experienced HIV-1-infected patients

OBJECTIVES

There are few data on clinical and virological factors associated with maraviroc virological response (VR) in clinical practice. This study aimed to identify factors associated with VR in 94 treatment-experienced, but CCR5 inhibitor-naive, HIV-1 patients switched to maraviroc-containing regimens.

METHODS

Patients with HIV-1 RNA viral load (VL) <50 copies/mL switching to an antiretroviral treatment containing maraviroc were followed. VR was defined at month 3 as VL <50 copies/mL. The impact of age, baseline tropism, zenith VL, nadir CD4 cell count and CD4 cell count, HIV subtype (B versus non-B), genotypic susceptibility score of treatment, once- or twice-daily treatment and presence of raltegravir in optimized background therapy on VR was investigated.

RESULTS

Baseline characteristics were: median age 49 years (range 25-73 years), median CD4 cell count 481 cells/mm(3) (range 57-1830 cells/mm(3)) and median nadir CD4 cell count 99 cells/mm(3) (range 3-585). Maraviroc was administered twice daily in 88 of 94 patients and once daily in 6 of 94 patients (300 mg/day for 4 of 6 and 150 mg/day for 2 of 6). At month 3, 89.4% of patients were responders. A better VR to a switch regimen containing maraviroc was associated with the B subtype (P = 0.0216) and a lower zenith VL (median of 5.24 and 5.70 log10 copies/mL for patients in success or in failure, respectively) in univariate analysis. Only B subtype was associated with a better VR in multivariate analysis.

CONCLUSIONS

This study evidenced the efficacy of a switch regimen containing maraviroc in clinical practice. VR was better for patients with a lower zenith VL and B subtype.

Evaluating the management of 493 patients presenting with bacteremia in 23 northern French hospitals

OBJECTIVES

We aimed to update the epidemiology of bacteremia and evaluate their management and short-term outcome.

METHODS

We conducted a prospective multicenter survey from October to November 2011. Consecutive patients with at least one positive blood culture (BC) were included in the study. We evaluated the type and adequacy of empirical and documented antibiotic therapy, time to active antibiotic therapy, compliance with guidelines, and 10-day outcome.

RESULTS

A total of 23 public and private hospitals and 633 patients (493 true pathogens and 140 contaminants) were included in the study. Patients' wards were medicine (57%), surgery (19%), intensive care (14%), onco/hematology (3.7%), pediatrics (3.4%), infectious diseases (1.8%), and obstetrics (1.2%). Main pathogens were Escherichia coli (36%), Staphylococcus aureus (16%), coagulase-negative staphylococci, and Klebsiella sp. (8% each). A total of 43 (8.7%) multidrug-resistant strains were observed, including 26 extended-spectrum beta-lactamase strains and 15 methicillin-resistant S. aureus strains. An antibiotic active against the isolated pathogen was used in 74% of empirical and 96% of documented therapies. Median time between BC and administration of an active drug was 0.61 day. Empirical antibiotic therapies were protocol-compliant in 77% of cases. Few (4%) patients with contaminated BC received an antibiotic therapy (all inappropriate). Day-10 mortality was 12.1%, higher in patients presenting with severe sepsis or septic shock (22.5%) than in patients presenting with non-severe bacteremia (7.1%; P<0.0001).

CONCLUSION

The management of bacteremia seems satisfactory in these volunteer hospitals but bacteremia remains a severe infection.

Two-Dimensional Frequency Resolved Optomolecular Gating of High-Order Harmonic Generation

Probing electronic wave functions of polyatomic molecules is one of the major challenges in high-harmonic spectroscopy. The extremely nonlinear nature of the laser-molecule interaction couples the multiple degrees of freedom of the probed system. We combine two-dimensional control of the electron trajectories and vibrational control of the molecules to disentangle the two main steps in high-harmonic generation-ionization and recombination. We introduce a new measurement scheme, frequency-resolved optomolecular gating, which resolves the temporal amplitude and phase of the harmonic emission from excited molecules. Focusing on the study of vibrational motion in N_{2}O_{4}, we show that such advanced schemes provide a unique insight into the structural and dynamical properties of the underlying mechanism.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Multi-channel electronic and vibrational dynamics in polyatomic resonant high-order harmonic generation

High-order harmonic generation in polyatomic molecules generally involves multiple channels of ionization. Their relative contribution can be strongly influenced by the presence of resonances, whose assignment remains a major challenge for high-harmonic spectroscopy. Here we present a multi-modal approach for the investigation of unaligned polyatomic molecules, using SF6 as an example. We combine methods from extreme-ultraviolet spectroscopy, above-threshold ionization and attosecond metrology. Fragment-resolved above-threshold ionization measurements reveal that strong-field ionization opens at least three channels. A shape resonance in one of them is found to dominate the signal in the 20-26 eV range. This resonance induces a phase jump in the harmonic emission, a switch in the polarization state and different dynamical responses to molecular vibrations. This study demonstrates a method for extending high-harmonic spectroscopy to polyatomic molecules, where complex attosecond dynamics are expected.

32-fs Kerr-lens mode-locked Yb:CaGdAlO₄ oscillator optically pumped by a bright fiber laser

In this study, we report on a pure Kerr-lens mode-locked Yb:CaGdAlO₄ oscillator optically pumped by a diffraction-limited fiber laser. At the repetition rate of 96 MHz, several configurations have been studied to achieve either pulse duration of 40 fs with average powers up to the watt level or shorter pulse duration down to 32 fs. To the best of our knowledge, this represents the shortest pulse duration ever achieved with an Yb-doped bulk material and the highest average power for sub-40-fs Kerr-lens mode-locked Yb-bulk oscillator.

Persistence of immune responses to the HPV-16/18 AS04-adjuvanted vaccine in women aged 15-55 years and first-time modelling of antibody responses in mature women: results from an open-label 6-year follow-up study

OBJECTIVE

Evaluation of the long-term HPV-16/18 AS04-adjuvanted vaccine immunogenicity persistence in women.

DESIGN

Multicentre, open-label, long-term follow-up (NCT00947115) of a primary phase-III study (NCT00196937).

SETTING

Six centres in Germany and Poland.

POPULATION

488 healthy women (aged 15-55 years, age-stratified into groups: 15-25, 26-45, and 46-55 years) who received three vaccine doses in the primary study.

METHODS

Immune responses were evaluated in serum and cervicovaginal secretion (CVS) samples 6 years after dose 1. Anti-HPV-16/18 geometric mean titres (GMTs) were measured by enzyme-linked immunosorbent assay (ELISA), and were used to fit the modified power-law and piecewise models, predicting long-term immunogenicity. Serious adverse events (SAEs) were recorded.

MAIN OUTCOME MEASURES

Anti-HPV-16/18 seropositivity rates and GMTs 6 years after dose 1.

RESULTS

At 6 years after dose 1, all women were seropositive for anti-HPV-16 and ≥97% were seropositive for anti-HPV-18 antibodies. GMTs ranged from 277.7 to 1344.6 EU/ml, and from 97.6 to 438.2 EU/ml, for anti-HPV-16 and anti-HPV-18, respectively. In all age groups, GMTs were higher (anti-HPV-16, 9.3-45.1-fold; anti-HPV-18, 4.3-19.4-fold) than levels associated with natural infection (29.8 EU/ml). A strong correlation between serum and CVS anti-HPV-16/18 levels was observed, with correlation coefficients of 0.81-0.96 (anti-HPV-16) and 0.69-0.84 (anti-HPV-18). Exploratory modelling based on the 6-year data predicted vaccine-induced anti-HPV-16/18 levels above natural infection levels for at least 20 years, except for anti-HPV-18 in the older age group (piecewise model). One vaccine-related and two fatal SAEs were reported.

CONCLUSIONS

At 6 years after vaccination, immune responses induced by the HPV-16/18 AS04-adjuvanted vaccine were sustained in all age groups.