In vitro activities of 18 antimicrobial agents against Staphylococcus aureus isolates from the Institut Pasteur of Madagascar

<p>Abstract</p> <p>Background</p> <p><it>Staphylococcus aureus</it>, one of the most frequently isolated pathogens in both hospitals and the community, has been particularly efficient at developing resistance to antimicrobial agents. In developed countries, as methicillin-resistant <it>S. aureus </it>(MRSA) has prevailed and, furthermore, as <it>S. aureus </it>with reduced susceptibility to vancomycin has emerged, the therapeutic options for the treatment of <it>S. aureus </it>infections have become limited. In developing countries and especially African countries very little is known concerning the resistance of <it>S. aureus </it>to antibiotics. In Madagascar no data exist concerning this resistance.</p> <p>Objective</p> <p>To update the current status of antibiotic resistance of <it>S. aureus </it>in Antananarivo, Madagascar.</p> <p>Methods</p> <p>Clinical <it>S. aureus </it>isolates were collected from patients at the Institut Pasteur of Madagascar from January 2001 to December 2005. Susceptibility tests with 18 antibiotics were performed by the disk diffusion method.</p> <p>Results</p> <p>Among a total of 574 isolates, 506 were from community-acquired infections and 68 from nosocomial infections. There was no significant difference in the methicillin resistance rate between community-acquired strains (33 of 506; 6.5%) and nosocomial strains (3 of 68, 4.4%). Many MRSA isolates were resistant to multiple classes of antibiotics. Resistance to tetracyclin, trimethoprim-sulfamethoxazole and erythromycin was more common. Among MRSA isolates resistance rates to rifampicin, fusidic acid, gentamicin and ciprofloxacin were lower than that observed with other drugs easily available in Madagascar. No isolates were resistant to glycopeptides.</p> <p>Conclusion</p> <p>The rate of methicillin-resistant <it>S. aureus </it>is not different between community-acquired and nosocomial infections and is still rather low in Madagascar.</p

Dissemination of multidrug resistant Acinetobacter baumannii in various hospitals of Antananarivo Madagascar

This study reports the dissemination of multidrug-resistant (MDR) OXA-23-producing Acinetobacter baumannii clones in hospitals in Antananarivo, Madagascar. A total of 53 carbapenem-resistant A. baumannii isolates were obtained from September 2006 to March 2009 in five hospitals. These resistant strains represent 44% of all A. baumannii isolates. The double disk synergy test was performed to screen for production of metallo-beta-lactamases. Polymerase chain reaction (PCR) and DNA sequencing were performed for the detection of bla(AmpC), bla(OXA-51),bla(OXA-23), bla(OXA-24), bla(IMP), bla(VIM). The presence of the insertion sequence ISAba1 relative to blaOXA-23 and blaOXA-51 was assessed by PCR. Isolates were typed by Rep-PCR. All the isolates were MDR and produced the OXA-23 carbapenemase, which was confirmed by sequencing. PCR analysis for AmpC and OXA-51 gave positive results for all strains studied. No isolates produced metallo-beta-lactamases. In all isolates ISAba1 laid upstream of blaOXA-23. The A. baumannii isolates were separated into two genotypes; genotype A had a higher prevalence (41 strains) than genotype B (12 strains). Genotype A was present in four hospitals, whilst genotype B had spread in two hospitals. The high frequency of MDR OXA-23-producing A. baumannii in various hospitals in Antananarivo is curious since carbapenems are not available in Madagascar, but it emphasises the need for infection control procedures and strict adherence to them to prevent the spread of these resistant organisms in Antananarivo and also the need to control the use of carbapenems in the future

Multidrug-resistant Mycobacterium tuberculosis, Bangui, Central African Republic

We investigated multidrug-resistant (MDR) Mycobacterium tuberculosis strains in Bangui, Central African Republic. We found 39.6% with the same spoligotype and synonymous single nucleotide polymorphism in the mutT1 gene. However, strains had different rpoB mutations responsible for rifampin resistance. MDR strains in Bangui may emerge preferentially from a single, MDR-prone family

Outbreak of Dengue and Chikungunya Fevers, Toamasina, Madagascar, 2006

An outbreak of dengue-like syndrome occurred in Toamasina from January through March 2006. Dengue type l or chikungunya viruses were detected in 38 of 55 patients sampled. Aedes albopictus was the only potential vector collected. Of 4,242 randomly selected representative residents interviewed retrospectively, 67.5% reported a dengue-like syndrome during this period

Risk Factors for Marburg Hemorrhagic Fever, Democratic Republic of the Congo

We conducted two antibody surveys to assess risk factors for Marburg hemorrhagic fever in an area of confirmed Marburg virus transmission in the Democratic Republic of the Congo. Questionnaires were administered and serum samples tested for Marburg-specific antibodies by enzyme-linked immunosorbent assay. Fifteen (2%) of 912 participants in a general village cross-sectional antibody survey were positive for Marburg immunoglobulin G antibody. Thirteen (87%) of these 15 were men who worked in the local gold mines. Working as a miner (odds ratio [OR] 13.9, 95% confidence interval [CI] 3.1 to 62.1) and receiving injections (OR 7.4, 95% CI 1.6 to 33.2) were associated with a positive antibody result. All 103 participants in a targeted antibody survey of healthcare workers were antibody negative. Primary transmission of Marburg virus to humans likely occurred via exposure to a still unidentified reservoir in the local mines. Secondary transmission appears to be less common with Marburg virus than with Ebola virus, the other known filovirus

Bio-inspired hydrogen production/uptake catalysis

International audienceIt was a great pleasure for us to accept the invitation of Pierre Braunstein, Editor-in-Chief of the Comptes Rendus Chimie , to guest-edit this thematic issue. We chose to devote it to an exciting field of research, which concerns the production and the oxidation of hydrogen by bio-inspired catalysts. Indeed, the development of economic and ecological processes of hydrogen production/uptake is a major goal in the perspective of a hydrogen economy. This thematic issue, entitled Bio-inspired hydrogen production/uptake catalysis , is dedicated to the chemists' efforts, in this multidisciplinary field at the interface of chemistry and biology, to conceive and to study new molecules inspired by the active sites of the [NiFe] and [FeFe] hydrogenases. The ultimate purpose of these theoretical and experimental studies is to achieve efficient electrocatalysts for the production or the oxidation of hydrogen through a better understanding of the mechanisms implied at the molecular level. We thank Pierre Braunstein very warmly for his invitation, as well as all the colleagues whose contributions allowed the edition of this thematic issue, which, we hope, will contribute to illustrate different aspects of the research performed by chemists in this challenging field

Contribution à l'étude des processus de transfert de couples {H+/e} et de transformation de ligands en relation avec la réduction de l'azote moléculaire

L'objectif de ce projet est l'étude de complexes modèles de la nitrogénase, l'enzyme qui catalyse la réduction biologique de l'azote en ammoniac. Le premier chapitre fait une synthèse des différents modèles chimiques envisagés dans la littérature. Un complément d'étude sur l'analyse électrochimique d'un de ces modèles, le complexe diazène dinucléaire du fer [{Fe(PPr3)(C14H12S4}2][m-NHNH)] est présenté dans le chapitre 2. Dans le dichlorométhane, le complexe présente deux étapes d'oxydation réversibles monoélectroniques et une étape d'oxydation irréversible multiélectronique. Dans le THF ou en présence d'une base, la réversibilité des deux premières étapes d'oxydation est affectée, indiquant une perte de proton au niveau du ligand diazène après oxydation. Un mécanisme qui permet de reproduire par simulation les différentes réponses électrochimiques obtenues est proposé dans ce chapitre. La réduction en milieu acide des complexes dinucléaires du molybdène [Mo2(cp)2(m-SMe)3(m-h2-CH3NNH)]+ et [Mo2(cp)2(m-SMe)3{m-h1-NN(H)CH3}]+ est traitée dans le chapitre 3. Le mode de coordination de l'entité {N=NCH3} coordinée aux centres métalliques contrôle le déroulement du processus de réduction en présence de protons. La coupure de la liaison N=N avec départ de NH3 et de MeNH3 est observée dans le cas du complexe [Mo2(cp)2(m-SMe)3{m-h1-NN(H)CH3}]+ uniquement, après sa réduction en milieu acide. La réactivité et le comportement électrochimique des complexes du tungstène [WX(NNH)(dppe)2], [WXH(NN)(dppe)2] (X = F, Br) et [WH2N2(dppe)2] sont étudiés dans le chapitre 4. Les résultats obtenus par électrochimie et par calculs DFT suggèrent une isomérisation entre les complexes [WX(NNH)(dppe)2] et [WXH(NN)(dppe)2] (X = F, Br) aux degrés d'oxydation II et III. La RMN 1H et 31P{1H} de [WH2N2(dppe)2] révèle l'instabilité de ce complexe en solution. Après réarrangement du ligand N2, le composé [WH2N2(dppe)2] conduit quantitativement à un complexe pseudo diazène, instable sous atmosphère d'hydrogène.BREST-BU Droit-Sciences-Sports (290192103) / SudocSudocFranceF