Current Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in Elderly French People: Troublesome Clones on the Horizon.

In 2015, we conducted at 44 healthcare facilities (HCFs) and 21 nursing homes (NHs) a 3-month bloodstream infection (BSI) survey, and a 1-day prevalence study to determine the rate of carriage of methicillin-resistant Staphylococcus aureus (MRSA) in 891 patients and 470 residents. We investigated the molecular characteristics of the BSI-associated and colonizing MRSA isolates, and assessed cross-transmission using double-locus sequence typing and pulsed-field gel electrophoresis protocol. The incidence of MRSA-BSI was 0.040/1000 patient-days (19 cases). The prevalence of MRSA carriage was 4.2% in patients (n = 39) and 8.7% in residents (n = 41) (p < 0.001). BSI-associated and colonizing isolates were similar: none were PVL-positive; 86.9% belonged to clonal complexes 5 and 8; 93.9% were resistant to fluoroquinolones. The qacA/B gene was carried by 15.8% of the BSI-associated isolates [3/3 BSI cases in intensive care units (ICUs)], and 7.7% of the colonizing isolates in HCFs. Probable resident-to-resident transmission was identified in four NHs. Despite generally reassuring results, we identified two key concerns. First, a worryingly high prevalence of the qacA/B gene in MRSA isolates. Antisepsis measures being crucial to prevent healthcare-associated infections, our findings raise questions about the potential risk associated with chlorhexidine use in qacA/B(+) MRSA carriers, particularly in ICUs. Second, NHs are a weak link in MRSA control. MRSA spread was not controlled at several NHs; because of their frequent contact with the community, conditions are favorable for these NHs to serve as reservoirs of USA300 clone for local HCFs

Bivalent mRNA-1273.214 vaccine effectiveness against SARS-CoV-2 omicron XBB* infections

In October of 2022, Qatar introduced COVID-19 bivalent vaccination for persons ≥ 12 years using the 50-μg mRNA-1273.214 vaccine combining SARS-CoV-2 ancestral and omicron BA.1 strains.1 We estimated this vaccine’s effectiveness against SARS-CoV-2 infection. Using Qatar’s national SARS-CoV-2 databases, we conducted a matched, retrospective, cohort study to compare infection incidence in the national cohort of persons who received the vaccine (bivalent cohort) to that in the national cohort of Qatar residents whose last vaccination was ≥6 months before follow-up start (no-recent-vaccination cohort; Supplementary Appendix 1). The 6-month cut-off was chosen because of negligible effectiveness of first-generation vaccines against omicron infection ≥ 6 months after vaccination.2 Incidence of infection was defined as the first SARS-CoV-2 PCR-positive or rapid-antigen-positive test after the start of follow-up, regardless of symptoms. Cohorts were balanced on observed confounders through exact matching. Follow-up started 7 days after the person in the bivalent cohort received their vaccine dose. Associations were estimated using Cox proportional-hazards models adjusted for the matching factors and testing rate

Woody Encroachment Extent and Its Associated Impacts on Plant and Herbivore Species Occurrence in Maswa Game Reserve, Tanzania

Research Article published by the Canadian Center of Science and Education Vol. 9, No. 3; 2019Habitat degradation caused by woody plant encroachment has been a common phenomenon in savanna ecosystems. An increasing woody plant cover in open grassland reduces grazing grounds and, consecutively, impacts mammalian herbivores, but structural changes and their associated impact have rarely been assessed and quantified. We analyzed the extent of woody plant encroachment via remote sensing and used transects and plots to assess encroaching woody plant species and their associated impacts on herbaceous plant and herbivore species in Maswa Game Reserve, Tanzania. We found that woody plant cover had increased by 0.5% to 2.6% per annum over the last thirty years, while in other parts of the park it has decreased by 0.5% to 1.5% per annum. Acacia drepanolobium was the dominant encroaching woody species, and the number of stems in heavily encroached sites was seven times and three times higher than in open grassland and at medium encroached sites, respectively. In encroached plots, grazer and mixed feeder species occurrence were reduced while the presence of browser species was slightly elevated. Furthermore, our findings show that bare ground cover is positively correlated with an increase of woody plant cover. Additionally, the number of herbaceous species slightly increased with the increase of woody plant encroachment, while the herbaceous cover was negatively correlated with the increase of woody plant cover. We suggest that fire regimes should be taken up to suppress the ongoing encroachment processes while strongly encroached sites might need mechanical intervention to control dense vegetation. This emphasis is on fire, particularly prescribed fire as a management tool of vegetation in Savanna ecosystem. We conclude that, woody plant encroachment is driven by different factors such as fire, mega-herbivores and topology that may interactively trigger woody plant encroachment in Savanna ecosystem

Conceptual synthesis of gasification-based biorefineries using thermodynamic equilibrium optimization models

An integrated biorefinery is a processing facility that converts biomass into a wide range of biochemical products and also provides a sustainable supply of biofuels and energy. One of its critical features is the ability to handle a wide variety of biomass feedstocks and the capacity to produce a portfolio of products through multiple conversion technologies. The gasification process is recognized as a promising option for initial processing of biomass, as it is a robust thermal conversion process. The composition of syngas, especially the ratio of H2 to CO, is crucial when the syngas is further converted to liquid fuels and chemicals. To optimize the production of syngas for application in an integrated biorefinery, a systematic approach is needed to design the system and predict its performance. In this work, a modular optimization approach to link a stoichiometric equilibrium model of biomass gasification and structural models of synthesis processes is developed. In this approach, all model components are solved simultaneously. The approach is used to evaluate the equilibrium composition of syngas, the optimum operating temperature, and the required types and amounts of oxidants. Two case studies are used to illustrate the approach. A sensitivity analysis is then performed to assess the most significant factors affecting the process economics in these examples. © 2011 American Chemical Society