[Comparison of Kinyoun, auramine O, and Ziehl-Neelsen staining for diagnosing tuberculosis at the National Tuberculosis Center in Burkina Faso]. / Comparaison des performances des colorations de Kinyoun et à l'auramine O, avec celle de Ziehl-Neelsen pour le diagnostic de la tuberculose au Centre national de lutte antituberculeuse du Burkina Faso.

CONTEXT: This study was conducted at the National Tuberculosis Center in Burkina Faso from October 2007 through May 2008. OBJECTIVE: Our objective was to compare the diagnostic performance of three staining methods: Kinyoun, auramine O, and Ziehl-Neelsen. METHODS: Ziehl-Neelsen staining served as the reference method to assess the diagnostic performance of Kinyoun and auramine O staining. In all, 616 sputum smears from 233 patients were read with each method to detect acid-fast bacilli. SPSS was used for data analysis. RESULTS: The results of auramine O staining showed positive diagnoses in 15.9% of the samples; sensitivity was 100%, specificity 95.6%, and the positive and negative predictive values 75.7% and 100% respectively. Kinyoun staining produced a positive diagnosis rate of 12%, sensitivity of 96.4%, specificity of 99.5%, and positive and negative predictive values of 96.4% and 99.5%. CONCLUSION: Our study indicates that auramine O staining had a better sensitivity for detecting acid-fast bacilli than Kinyoun staining. Accordingly, the use of auramine O staining should increase the detection rate for pulmonary tuberculosis in Burkina Faso.

FcγRIIa polymorphism and anti-malaria-specific IgG and IgG subclass responses in populations differing in susceptibility to malaria in Burkina Faso.

FcγRIIa is known to be polymorphic; and certain variants are associated with different susceptibilities to malaria. Studies involving the Fulani ethnic group reported an ethnic difference in FcγRIIa-R131H genotype frequencies between the Fulani and other sympatric groups. No previous studies have addressed these questions in Burkina Faso. This study aimed to assess the influence of FcγRIIa-R131H polymorphism on anti-falciparum malaria IgG and IgG subclass responses in the Fulani and the Mossi ethnic groups living in Burkina Faso. Healthy adults more than 20 years old belonging to the Mossi or the Fulani ethnic groups were enrolled for the assessment of selected parasitological, immunological and genetic variables in relation to their susceptibility to malaria. The prevalence of the Plasmodium falciparum infection frequency was relatively low in the Fulani ethnic group compared to the Mossi ethnic group. For all tested antigens, the Fulani had higher antibody levels than the Mossi group. In both ethnic groups, a similar distribution of FcγRIIa R131H polymorphism was found. Individuals with the R allele of FcγRIIa had higher antibody levels than those with the H allele. This study confirmed that malaria infection affected less the Fulani group than the Mossi group. FcγRIIa-R131H allele distribution is similar in both ethnic groups, and higher antibody levels are associated with the FcγRIIa R allele compared to the H allele.

Do antibody responses to malaria vaccine candidates influenced by the level of malaria transmission protect from malaria?

OBJECTIVES: To examine whether the humoural response to malaria vaccine candidate antigens, Plasmodium falciparum [circumsporozoite repetitive sequence (NANP)(5) GLURP fragments (R0 and R2) and MSP3] varies with the level of malaria transmission and to determine whether the antibodies (IgG) present at the beginning of the malaria transmission season protect against clinical malaria. METHODS: Cross-sectional surveys were conducted to measure antibody response before, at the peak and at the end of the transmission season in children aged 6 months to 10 years in two villages with different levels of malaria transmission. A cohort study was performed to estimate the incidence of clinical malaria. RESULTS: Antibodies to these antigens showed different seasonal patterns. IgG concentrations to any of the four antigens were higher in the village with high entomological inoculation rate. Multivariate analysis of combined data from the two villages indicated that children who were classified as responders to the selected antigens were at lower risk of clinical malaria than children classified as non-responders [(NANP)(5) (incidence rate ratio (IRR) = 0.65, 95% CI: 0.46-0.92; P = 0.016), R0 (IRR = 0.69, 95% CI: 0.48-0.97; P = 0.032), R2 (IRR = 0.73, 95% CI: 0.50-1.06; P = 0.09), MSP3 (IRR = 0.52, 95% CI: 0.32-0.85; P = 0.009)]. Fitting a model with all four antibody responses showed that MSP3 looked the best malaria vaccine candidate (IRR = 0.63; 95% CI: 0.38-1.05; P = 0.08). CONCLUSION: Antibody levels to the four antigens are affected by the intensity of malaria transmission and associated with protection against clinical malaria. It is worthwhile investing in the development of these antigens as potential malaria vaccine candidates.

Chemical composition and antibacterial activities of the essential oils of Lippia chevalieri and Lippia multiflora from Burkina Faso.

The chemical composition of the essential oils of Lippia chevalieri and Lippia multiflora obtained from the air-dried leaves by hydrodistillation were analysed using GC and GC-MS. L. chevalieri and L. multiflora belonged to thymol/p-cymene/2-phenyl ethyl propionate and thymol/p-cymene/thymyl acetate chemotypes, respectively. The essential oils were also tested against 09 strains using a broth microdilution method. The Gram-negative bacteria were the most sensitive. The essential oil of L. multiflora was the most active.

Methanobacterium congolense sp. nov., from a methanogenic fermentation of cassava peel.

Strain CT, a non-motile, mesophilic, hydrogenotrophic, methanogenic bacterium, was isolated from an anaerobic digester used for the treatment of raw cassava-peel waste in Congo. The cells were rods, 0.4-0.5 x 2-10 microm in size, and stained Gram-positive. Hydrogen and carbon dioxide were the only substrates that supported growth and methane production. Methane production, but not growth, occurred with CO2 in the presence of either 2-propanol, 2-butanol or cyclopentanol as hydrogen donors. The temperature range for growth was 25-50 degrees C, the optimum being between 37 and 42 degrees C. The optimum pH for growth was 7.2; consistent growth and methane production were not observed below pH 5.9 or above pH 8.2. The doubling time under optimal growth conditions was 7.5 h. The DNA base composition was 39.5 mol% G+C. On the basis of 16S rRNA gene sequence analysis and phenotypic characteristics, the isolate is proposed as a new species of the genus Methanobacterium, namely Methanobacterium congolense sp. nov. The type strain is strain CT (= DSM 7095T = OCM 779T).

Isolation and characterization of Desulfovibrio burkinensis sp. nov. from an African ricefield, and phylogeny of Desulfovibrio alcoholivorans.

A sulfate-reducing bacterium, strain HDvT (T = type strain), was isolated from an anoxic ricefield soil. Cells were Gram-negative, non-sporulating curved rods motile by means of a single polar flagellum. Cytochrome c3 and desulfoviridin were present. In the presence of sulfate, glycerol, 1,2- and 1,3-propanediol, dihydroxyacetone, pyruvate, lactate, fumarate, maleate, malate and succinate were incompletely oxidized mainly to acetate. Sulfite, thiosulfate, elemental sulfur, fumarate, maleate and malate were utilized as alternative electron acceptors. In the absence of added electron acceptors, pyruvate, fumarate, maleate, malate and dihydroxyacetone were fermented. The DNA base composition was 67 mol% G + C. The phylogenetic, phenotypic and physiological characteristics of strain HDvT indicate that it is a new species of the genus Desulfovibrio, for which the name Desulfovibrio burkinensis sp. nov. is proposed; the type strain is HDvT (= DSM 6830T). Phylogenetic analysis confirmed that Desulfovibrio alcoholivorans was a distinct species supporting the previously published phenotypic data.

Anaerobic degradation of 1,2-propanediol by a new Desulfovibrio strain and D. alcoholovorans.

A sulfate-reducing bacterium, strain HDv, was isolated from the anoxic soil of a ricefield using lactate as electron donor. Cells were gram-negative, motile, nonsporulating curved rods, with single polar flagella. Substrates were incompletely oxidized to acetate and included glycerol, 1,2- and 1,3-propanediol. Sulfate, sulfite, thiosulfate, elemental sulfur, fumarate, maleate, and malate were utilized as electron acceptors. Pyruvate, fumarate, maleate, malate and dihydroxyacetone were fermented. Desulfoviridin and c-type cytochromes were present. The DNA base composition was 66.6 +/- 0.3 mol% G+C. The isolate was identified as a Desulfovibrio sp.; its metabolic properties were somewhat different from those of previously described Desulfovibrio species. Comparative biochemical study of 1,2-propanediol dissimilation by the new isolate and Desulfovibrio alcoholovorans showed that NAD-dependent dehydrogenases play a key role in the catabolism of this substrate. The hypothetical pathways of 1,2-propanediol degradation by Desulfovibrio spp. are presented.

Specific synthetic peptides for detection of and discrimination between HIV-1 and HIV-2 infection.

A panel of highly purified synthetic oligopeptides representing defined parts of the gag and env proteins of HIV-1 and HIV-2 were used as antigens in ELISA for serodiagnosis of HIV-1 and HIV-2 infection. The analysis included sera from 321 HIV-infected patients and 201 healthy controls from the Ivory Coast, where the prevalence is high for both HIV-1 and HIV-2, and sera from European HIV-1-infected individuals. All sera from HIV-1-infected individuals reacted with a 20 amino acid (a.a.) peptide JB-4c (a.a. 594-613) derived from a highly immunogenic conserved region of the external part of gp41. An equally good response was seen in the HIV-2-infected individuals to a 20 a.a. peptide, JB-16c, from the corresponding part of HIV-2 gp36. Both HIV-1- and HIV-2-seropositive individuals responded well to a peptide, JB-8pc (a.a. 427-448), representing the C-terminal end of the putative CD4-binding site of gp120 of HIV-1. The frequency of reactivity to three selected HIV-1 gag peptides derived from p17 and p15 was 60-70% in both HIV-1 and HIV-2-positive sera. To distinguish between HIV-1 and HIV-2 infection, the sera were titrated against the peptides. Although there was a high degree of cross-reactivity at lower serum dilutions, it was possible to discriminate the infections at higher dilutions to the HIV-1 and HIV-2 gp41/gp36 peptides JB-4c and JB-16c. Analysis of serum reactivity to several selected peptides thus allowed the identification of HIV infection, and the discrimination between HIV-1 and HIV-2.(ABSTRACT TRUNCATED AT 250 WORDS)