Effets de Biophytum petersianum (Oxalidaceae) sur la pression artérielle chez le rat Wistar

Résumé  Le présent travail évalue le potentiel hypotensif et les mécanismes d’action associés de l’extrait semi-éthanolique de Biophytum petersianum chez le rat Wistar normotendu. La méthode sanglante est utilisée pour mesurer la pression artérielle. L’extrait est administré par v.i. aux doses uniques de 27, 54 et 81 mg/kg. L’extrait à 54 mg/kg et la clonidine à 0,5 mg/kg sont administrés à des animaux différents, suivie d’une bi-occlusion carotidienne. La même dose d’extrait est administrée après bivagotomie et blocage des récepteurs muscariniques par l’atropine. Les résultats montrent que l’effet hypotenseur de l’extrait ne passe pas par l’inhibition du système nerveux sympathique mais implique partiellement la stimulation du système parasympathique puisque cet effet est bloqué par l’atropine. Ces résultats confirment l’utilisation traditionnelle de B. petersianum dans le traitement de l’hypertension.      

High-Resolution Typing of Leptospira interrogans Strains by Multispacer Sequence Typing

Leptospirosis is a worldwide zoonosis which is responsible for the typical form of Weil''s disease. The epidemiological surveillance of the Leptospira species agent is important for host prevalence control. Although the genotyping methods have progressed, the identification of some serovars remains ambiguous. We investigated the multispacer sequence typing (MST) method for genotyping strains belonging to the species Leptospira interrogans, which is the main agent of leptospirosis worldwide. A total of 33 DNA samples isolated from the reference strains of L. interrogans serogroups Icterohaemorrhagiae, Australis, Canicola, and Grippotyphosa, which are the most prevalent serogroups in France, were analyzed by both the variable-number tandem-repeat (VNTR) and MST methods. An MST database has been constructed from the DNA of these reference strains to define the MST profiles. The MST profiles corroborated with the VNTR results. Moreover, the MST analysis allowed the identification at the serovar level or potentially to the isolate level for strains belonging to L. interrogans serovar Icterohaemorrhagiae, which then results in a higher resolution than VNTR (Hunter-Gaston index of 0.94 versus 0.68). Regarding L. interrogans serogroups Australis, Canicola, and Grippotyphosa, the MST and VNTR methods similarly identified the genotype. The MST method enabled the acquisition of simple and robust results that were based on the nucleotide sequences. The MST identified clinical isolates in correlation with the reference serovar profiles, thus permitting an epidemiological surveillance of circulating L. interrogans strains, especially for the Icterohaemorrhagiae serogroup, which includes the most prevalent strains of public health interest.     

Which antibiotics and breakpoints should be used for Aeromonas susceptibility testing? Considerations from a comparison of agar dilution and disk diffusion methods using Enterobacteriaceae breakpoints

Aeromonas species are environmental organisms that are responsible for numerous infections in humans and animals. Their antimicrobial susceptibility is usually evaluated using Enterobacteriaceae breakpoints. Although disk diffusion and minimum inhibitory concentration (MIC)-based methods are important for infectious disease management and epidemiological surveys of resistance, comparisons between these two methods have not been extensively studied for Aeromonas isolates. We propose the first extensive comparison of agar dilution and disk diffusion susceptibility testing methods, performed for 20 antimicrobial agents, including unevaluated or incompletely evaluated antibiotics (ticarcillin with or without clavulanic acid, ertapenem, tigecycline), on 146 Aeromonas isolates affiliated with six Aeromonas species via molecular means. We evaluated the level of agreement between Enterobacteriaceae breakpoints-based methods. Reliable agreement (>95%) was observed for piperacillin, cefotaxime, cefepime, nalidixic acid, ofloxacin, ciprofloxacin, gentamicin, amikacin, tetracycline and cotrimoxazole, whereas marked inconsistencies between the methods were noted for carbapenems, amoxicillin-clavulanic acid, ticarcillin, ticarcillin-clavulanic acid, tobramycin and tigecycline. The results indicate that beta-lactam and aminoglycoside susceptibility testing should be limited to piperacillin, cephems, gentamicin and amikacin. Co-amoxiclav should be avoided given the lack of agreement between the two methods. Adjusting the zone diameter breakpoints for tigecycline and cefoxitin could also improve the agreement to >95% and reduce the error rates to acceptable levels.     

The Opposite of Denial: Social Learning at the Onset of the Ebola Emergency in Liberia

This study analyzes findings from a rapid-response community-based qualitative research initiative to study the content of Ebola-related communications and the transmission of Ebola-related behaviors and practices through mass media communications and social learning in Monrovia, Liberia during August–September 2014. Thirteen neighborhoods in the common Monrovia media market were studied to appraise the reach of health communications and outreach regarding Ebola prevention and response measures. A World Health Organization (WHO) research team collected data on social learning and Ebola knowledge, attitudes, and practices through focus group–based discussions and key informant interviews over a 14-day period to assess the spread of information during a period of rapidly escalating crisis. Findings show that during a 2-week period, Monrovia neighborhood residents demonstrated rapid changes in beliefs about the source of Ebola, modes of contagion, and infection prevention and control (IPC) practices, discarding incorrect information. Changes in practices tended to lag behind the acquisition of learning. Findings also show that many continued to support conspiracy theories even as correct information was acquired. The implications for community engagement are substantial: (1) Under conditions of accelerating mortality, communities rapidly assimilate health information and abandon incorrect information; (2) Behavior change is likely to lag behind changes in beliefs due to local physical, structural, sociocultural, and institutional constraints; (3) Reports of “resistance” in Monrovia during the Ebola response were overstated and based on a limited number of incidents, and failed to account for specific local conditions and constraints.     

Rubella in pregnant women in Abidjan (Ivory Coast)

1,143 serums samples collected from pregnant females at first term were tested for the presence of rubella haemagglutination inhibition antibodies. Rubella antibodies were present in 679 (59.4%) of the pregnant females and 464 (40.6%) were seronegative. No statistically significant difference was found in the prevalence of rubella specific antibodies in three age categories considered. 155 positive serum samples for rubella antibodies (IHA) were tested afterward retrospectively for rubella-specific IgM by ELISA technic, and 14 (9.03%) were positive.     

Rat bite fever caused by Streptobacillus moniliformis in a child: human infection and rat carriage diagnosed by PCR

A child owning pet rats developed an eruptive fever with blisters, polyarthritis, and spectacular desquamation of the hands. Streptobacillus moniliformis was identified after culture of the child's blister fluid and was detected in rat samples by molecular methods. Such detection in the pet of a human victim of rat bite fever has not been reported previously.