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

Prospective Study of Chikungunya Virus Acute Infection in the Island of La Réunion during the 2005–2006 Outbreak

BACKGROUND:Chikungunya virus (CHIKV) is a recently re-emerged arthropod borne virus responsible for a massive outbreak in the Indian Ocean and India, and extended to Southeast Asia as well as Italy. CHIKV has adapted to Aedes albopictus, an anthropophilic mosquito species widely distributed in Asia, Europe, Africa and America. Our objective was to determine the clinical and biological features of patients at the acute phase of CHIKV infection. METHODS AND FINDINGS:A prospective study enrolled 274 consecutive patients with febrile arthralgia recorded at the Emergency Department of the Groupe Hospitalier Sud-Réunion between March and May 2006. Three groups were defined: one group of 180 viremic patients (positive CHIKV RT-PCR), one group of 34 patients with acute post-viremic infection (negative CHIKV RT-PCR, positive anti-CHIKV IgM and negative IgG), and one group of 46 uninfected patients (negative CHIKV RT-PCR, anti-CHIKV IgM and IgG). Bivariate analyses of clinical and biological features between groups were performed. Patients with CHIKV viremia presented typically with asymmetrical bilateral polyarthralgia (96.5%) affecting the lower (98%) and small joints (74.8%), as well as asthenia (88.6%), headache (70%), digestive trouble (63.3%), myalgia (59%), exanthems (47.8%), conjunctival hyperhemia (23%) and adenopathy (8.9%). Vertigo, cutaneous dysesthesia, pharyngitis and haemorrhages were seldom observed. So far unreported symptoms such as chondrocostal arthralgia (20%), entesopathies (1.6%), talalgia (14%) were also noted. Prurit was less frequent during the viremic than post-viremic phase (13.9% vs. 41.2%; p<0.001), whereas lymphopenia was more frequent (87.6% vs. 39.4%; p<0.001). Others biological abnormalities included leukopenia (38.3%), thrombocytopenia (37.3%), increased ASAT and ALAT blood levels (31.6 and 7.3%, respectively) and hypocalcemia (38.7%). Lymphopenia <1,000/mm(3) was very closely associated with viremic patients (Yule coefficient 0.82, positive predictive value 92.3%). Age under 65 was associated with a benign course, as no patients younger than 65 had to be hospitalized (Yule coefficient 0.78). CONCLUSIONS:The diagnosis of CHIKV infection in acute phase is based on commonly accepted clinical criteria (fever and arthralgia), however clinical and biological diffrences exist in acute phase depending on whether or not the patient is within the viremic phase of the infection

Electrochemical oxidation and protonation of a bridging amide ligand at a dinuclear metal-sulfur site

International audienceThe electrochemical oxidation of the amide complex [Mo2(cp)2(μ-SMe)3(μ-NH2)] 1 (cp = η5-C5H5) has been investigated in tetrahydrofuran (thf) and MeCN electrolytes by cyclic voltammetry, controlled-potential electrolysis and coulometry. The two-electron oxidation of 1 leads to the release of a proton and to the formation of the imide derivative [Mo2(cp)2(μ-SMe)3(μ-NH)]+ 2. In MeCN, this reaction is reversible. The protonation of 1 has been shown to produce a complex in which a NH3 ligand is bound to a Mo centre; the protonated complex is stabilized by co-ordination of the anion of the acid, of the solvent or of a substrate to the neighbouring metal centre. The protonation performed in thf in the presence of chloride produces [Mo2(cp)2(μ-SMe)3(μ-Cl)] which is the precursor of the amide complex 1. The final protonation product formed in MeCN is [Mo2(cp)2(μ-SMe)3(MeCN)2]+, which also is a precursor of 1. Therefore, these experiments allow the construction of a hydrazine disproportionation cycle

Electrochemical oxidation and protonation of a bridging amide ligand at a dinuclear metal-sulfur site

International audienceThe electrochemical oxidation of the amide complex [Mo2(cp)2(μ-SMe)3(μ-NH2)] 1 (cp = η5-C5H5) has been investigated in tetrahydrofuran (thf) and MeCN electrolytes by cyclic voltammetry, controlled-potential electrolysis and coulometry. The two-electron oxidation of 1 leads to the release of a proton and to the formation of the imide derivative [Mo2(cp)2(μ-SMe)3(μ-NH)]+ 2. In MeCN, this reaction is reversible. The protonation of 1 has been shown to produce a complex in which a NH3 ligand is bound to a Mo centre; the protonated complex is stabilized by co-ordination of the anion of the acid, of the solvent or of a substrate to the neighbouring metal centre. The protonation performed in thf in the presence of chloride produces [Mo2(cp)2(μ-SMe)3(μ-Cl)] which is the precursor of the amide complex 1. The final protonation product formed in MeCN is [Mo2(cp)2(μ-SMe)3(MeCN)2]+, which also is a precursor of 1. Therefore, these experiments allow the construction of a hydrazine disproportionation cycle

Recent advances in the chemistry of tris(thiolato) bridged cyclopentadienyl dimolybdenum complexes

International audienceThe chemistry of tris(thiolato) bridged dimolybdenum compounds in low oxidation states (mostly III) is considered. Various synthetic routes lead to chalcogenide-bridged dinuclear complexes of group 6 metals (mainly Mo). Extensive chemistry of these derivatives is reviewed. Their reactivity towards various reagents such as alkynes, isonitriles, nitriles, propargylic alcohols, azides, hydrazines, carbon disulfide…, demonstrates their ability for activation of small unsaturated molecules through new C–X (X = C, N, O, S…) bonds formation or cleavage

A few selected aspects of electrode-induced reactions at mono- and dinuclear molybdenum-sulfur centres.

International audienceEditing an encyclopedia has already been a formidable task in the not too distant past—it is an even more difficult task today. Thus it is not surprising to realize that an encyclopedia covering electrochemistry, an extremely diverse and multidisciplinary area of research and development, has not been published again after the “Encyclopedia of the Electrochemistry of the Elements” that has been finished decades ago by A.J. Bard—and this work actually covered only very selected and limited areas of the field. Thus the present volume, being a part of an eleven-book enterprise, attempts to be a building block of a work standing in the tradition of famous predecessors (e.g.. Encyclopédie by D. Diderot and J. d’Alembert 1751–1775).A certainly very challenging task is a complete overview of experimental methods including both traditional (classical) and nontraditional (e.g. spectroscopic or surface analytical) methods because of the extremely large number of methods in particular in the..

Electrochemical Reduction of Nitrogenous Ligands at a Conserved Dinuclear Metal−Sulfur Site: Cleavage of the NN Bond of Phenyldiazene and Reduction of an Imide to NH 3

International audienceThe electrochemical reduction of the phenyldiazene complex [Mo2(cp)2(μ-SMe)3(μ-η2-HNNPh)]+ in the presence of HX (X = TsO, CF3CO2) produces aniline and an ammino derivative. This may involve [Mo2(cp)2(μ-SMe)3(μ-NH)]+ as an intermediate since the imide complex also reduces to the ammino derivative in the presence of HX. These electrochemical steps complete a cycle whereby a phenyldiazenido ligand coordinated to the {Mo2(cp)2(μ-SMe)3+} core is cleaved to PhNH2 and NH3 by successive proton- and electron-transfer steps