Epidemiology of Methicillin-resistant and Methicillin-sensitive Staphylococcus aureus infections in Lebanon

Background. Methicillin-resistant Staphylococcus aureus (MRSA) is a prevalent pathogen associated with significant morbidity and mortality. In Lebanon, MRSA rates have recently started to rise. We aimed to determine risk factors for acquiring MRSA and Methicillin-sensitive Staphylococcus aureus (MSSA) infections and identify independent risk factors for in-hospital mortality among patients with S. aureus infection. Methods. We used a case-case-control study design that included patients with infections and compared them to uninfected controls. Two multivariable regression models were constructed to determine variables associated with acquiring MRSA and MSSA infections. We explored independent predictors of mortality in the overall population compared with the MRSA subgroup. Results. 356 patients with S. aureus infections were identified and compared to 208 uninfected controls. A recent history of surgery and underlying diabetes were independent risk factors for acquiring both infections. Having a urinary catheter for more than 6 days and steroid therapy were unique risk factors for MRSA infection (aOR 28.1, 95% CI 3.5-223.6 and 3.7, 95% CI 1.6-8.7, respectively). Risk factors exclusively associated with MRSA infection included ICU admission, acute renal failure, and malignancy. Conclusions. Risk factors associated with MRSA infection are distinct from those associated with MSSA infection. This can be used to risk stratify patients and will aid in choosing empirical antibiotic therapy

Knowledge, Perception, Attitudes and Behavior on Influenza Immunization and the Determinants of Vaccination

BACKGROUND: We sought to determine the knowledge of, perception, attitudes, and behaviors toward influenza virus and immunization, and the determinants of vaccination among students, patients, and Healthcare Workers (HCWs) at the American University of Beirut and its affiliated Medical Center. METHODS: We conducted a cross-sectional study between October 2016 and January 2017 utilizing a self-administered questionnaire that was provided to 247 randomly selected adult participants. Data collected included socio-demographic characteristics, prior vaccination against influenza, knowledge, perception, attitudes, and behaviors toward influenza and influenza immunization. A multivariable regression model was used to evaluate for independent associations between the different variables and regular or yearly vaccination as a primary outcome. RESULTS: The overall survey response rate was 77%. A substantial proportion of respondents (47.4%) had never received the influenza vaccine. Only 10.2% of students, 19.1% of patients, and 35.6% of HCWs reported regular or yearly influenza vaccine uptake. HCWs had the lowest knowledge score about influenza and its vaccine despite high self-reported levels of knowledge. Barriers to vaccinations included lack of information (31%), fear of adverse effects (29%), and a perception of not being at risk (23%). Several factors were independently associated with regular or yearly vaccination uptake including having children (adjusted OR = 3.8; 95% CI 1.2-12.5), a "very good" self-reported level of knowledge (OR = 16.3; 95% CI 1.4-194.2) and being afraid of the consequences of influenza (OR = 0.2; 95% CI 0.1-0.6). CONCLUSION: Adherence rates with regular or yearly vaccination against influenza remain low across all study groups. We were able to identify predictors as well as barriers to vaccination. Future awareness and vaccination campaigns should specifically aim at correcting misconceptions about vaccination, particularly among HCWs, along with addressing the barriers to vaccination. Predictors of vaccination should be integrated in the design of future campaigns

Mesures de précision dans la désintégration beta de l'6He

Les mesures de précision dans la désintégration beta jouent un rôle essentiel dans la recherche de nouvelle physique, au-delà du modèle standard (MS), en recherchant des contributions "exotiques" telles que des interactions scalaires et tensorielles au sein de l'interaction faible. L'existence de telles interactions induit des déviations de certaines observables par rapport à leurs prédictions dans le MS. L'étude du spectre en énergie de la particule beta permet de sonder ces interactions. L'objectif de ce travail est d'effectuer la mesure la plus précise du spectre en énergie beta dans la désintégration du 6He, afin d'extraire le terme d'interférence de Fierz bGT avec une précision de l'ordre de 4 *10^{-3}. Ce terme dépend linéairement des constantes de couplage exotiques, permettant ainsi de rechercher ou de contraindre la présence d'interactions tensorielles dans la désintégration nucléaire beta. L'effet instrumental principal observé dans les mesures précédentes du spectre en énergie beta réside dans la perte d'énergie due à la rétrodiffusion des électrons en dehors du volume du détecteur. Une nouvelle technique est utilisée pour s'affranchir de cet effet. Elle consiste en l'utilisation d'un faisceau de ions 6He+ à très basse énergie (25 keV) déposé entre deux détecteurs à scintillation formant un calorimètre 4pi. L'utilisation de cette technique garantit le dépôt de toute l'énergie des particules beta détectées. Une expérience avec cette configuration a été réalisée au Grand Accélérateur National d'Ions Lourds (GANIL) en 2021. Cette thèse introduira le contexte général du projet b-STILED, décrira la configuration expérimentale, rendra compte de la mesure la plus précise de la demi-vie de 6He et de la mesure de la forme du spectre d'énergie beta avec tous les défis inhérents à une telle mesure, et présentera nos résultats préliminaires sur l'extraction du terme d'interférence de Fierz à partir de la forme du spectre en énergie beta.Precision measurements in beta decay play an essential role in the search for new physics beyond the standard model (SM), by probing “exotic” phenomena such as scalar and tensor interactions in the electroweak sector. The existence of such interactions induces deviations on certain observables away from their SM predictions. The study of the full beta-energy spectrum offers a sensitive property to probe these interactions. The goal of this work is to perform the most precise measurement of the beta energy spectrum in 6He decay, in order to extract the Fierz interference term bGT with a precision in the order of 4*10^{-3}. This term depends linearly on exotic coupling constants, allowing to search for or to constrain the presence of tensor interactions in nuclear beta decay. The main instrumental effect observed in previous measurements of the beta energy spectrum resides in the energy loss due to electrons backscattering outside the detector volume. A new technique is used to overcome this effect. It consists of using a very low energy beam of 6He+ ions (25 keV) deposited between two scintillation detectors forming a 4pi calorimeter. The use of this technique ensures the deposition of the entire energy of the detected beta particles. An experiment with this setup was performed at the Grand Accélérateur National d’Ions Lourds (GANIL) in 2021. This thesis will introduce the general context of the b-STILED project, describe the experimental setup, report the most precise measurement of 6He half-life and the measurement of the shape of the betaenergy spectrum with all the challenges that come with such a measurement, and provide preliminary results on the extraction of the Fierz interference term from the beta energy spectrum

Mesures de précision dans la désintégration beta de l'6He

Precision measurements in beta decay play an essential role in the search for new physics beyond the standard model (SM), by probing “exotic” phenomena such as scalar and tensor interactions in the electroweak sector. The existence of such interactions induces deviations on certain observables away from their SM predictions. The study of the full beta-energy spectrum offers a sensitive property to probe these interactions. The goal of this work is to perform the most precise measurement of the beta energy spectrum in 6He decay, in order to extract the Fierz interference term bGT with a precision in the order of 4*10^{-3}. This term depends linearly on exotic coupling constants, allowing to search for or to constrain the presence of tensor interactions in nuclear beta decay. The main instrumental effect observed in previous measurements of the beta energy spectrum resides in the energy loss due to electrons backscattering outside the detector volume. A new technique is used to overcome this effect. It consists of using a very low energy beam of 6He+ ions (25 keV) deposited between two scintillation detectors forming a 4pi calorimeter. The use of this technique ensures the deposition of the entire energy of the detected beta particles. An experiment with this setup was performed at the Grand Accélérateur National d’Ions Lourds (GANIL) in 2021. This thesis will introduce the general context of the b-STILED project, describe the experimental setup, report the most precise measurement of 6He half-life and the measurement of the shape of the betaenergy spectrum with all the challenges that come with such a measurement, and provide preliminary results on the extraction of the Fierz interference term from the beta energy spectrum.Les mesures de précision dans la désintégration beta jouent un rôle essentiel dans la recherche de nouvelle physique, au-delà du modèle standard (MS), en recherchant des contributions "exotiques" telles que des interactions scalaires et tensorielles au sein de l'interaction faible. L'existence de telles interactions induit des déviations de certaines observables par rapport à leurs prédictions dans le MS. L'étude du spectre en énergie de la particule beta permet de sonder ces interactions. L'objectif de ce travail est d'effectuer la mesure la plus précise du spectre en énergie beta dans la désintégration du 6He, afin d'extraire le terme d'interférence de Fierz bGT avec une précision de l'ordre de 4 *10^{-3}. Ce terme dépend linéairement des constantes de couplage exotiques, permettant ainsi de rechercher ou de contraindre la présence d'interactions tensorielles dans la désintégration nucléaire beta. L'effet instrumental principal observé dans les mesures précédentes du spectre en énergie beta réside dans la perte d'énergie due à la rétrodiffusion des électrons en dehors du volume du détecteur. Une nouvelle technique est utilisée pour s'affranchir de cet effet. Elle consiste en l'utilisation d'un faisceau de ions 6He+ à très basse énergie (25 keV) déposé entre deux détecteurs à scintillation formant un calorimètre 4pi. L'utilisation de cette technique garantit le dépôt de toute l'énergie des particules beta détectées. Une expérience avec cette configuration a été réalisée au Grand Accélérateur National d'Ions Lourds (GANIL) en 2021. Cette thèse introduira le contexte général du projet b-STILED, décrira la configuration expérimentale, rendra compte de la mesure la plus précise de la demi-vie de 6He et de la mesure de la forme du spectre d'énergie beta avec tous les défis inhérents à une telle mesure, et présentera nos résultats préliminaires sur l'extraction du terme d'interférence de Fierz à partir de la forme du spectre en énergie beta

Sites of colonization in hospitalized patients with infections caused by extended-spectrum beta-lactamase organisms: a prospective cohort study

Abstract Background The objective of this study was to determine whether patients infected with extended-spectrum beta-lactamase (ESBL)-producing organisms are colonized at multiple body sites. Methods This was a prospective cohort study at a tertiary care center in Beirut, Lebanon. Hospitalized patients with infections caused by ESBL-producing organisms were included. Cultures were obtained from the primary site of infection as well as from other sites (skin, nasopharynx, urine, rectum). Molecular analysis was performed on isolates to determine clonal relatedness. Results One hundred patients were included in the study. Only 22 patients had positive cultures from sites other than the primary site of infection. The most common ESBL gene was CTX-M-15 followed by TEM-1. In 11 of 22 patients, isolates collected from the same patient were 100% genetically related, while in the remaining patients, genomic relatedness ranged from 42.9% to 97.1%. Conclusions Colonization at sites other than the primary site of infection was not common among our patient population infected with ESBL-producing organisms. The dynamics of transmission of these bacterial strains should be studied in further prospective studies to determine the value of routine active surveillance and the need for expanded precautions in infected and colonized patients

High precision measurement of the 6^6He half-life

The half-life of 6He has been measured using a low energy radioactive beam implanted in a YAP scintillator and recording decay events in a 4$\pi$ geometry. Events were time-stamped with a digital data acquisition system enabling a reliable control of dead-time effects and detector gain variations. The result, $T_{1/2} = (807.25 \pm 0.16_{\rm stat} \pm 0.11_{\rm sys}$)~ms, provides the most precise value obtained so far and is consistent with the only previous measurement having a precision smaller than 0.1%. This resolves the longstanding discrepancy previously observed between two sets of measurements

Precision measurements in the beta decay of 6He

International audienceWe report here about the ongoing data analysis of an experiment performed at GANIL with a 25 keV 6He+ beam to determine the Fierz interference term from the β particles energy spectrum