Phytochemical screening, Antimycobacterial activity of three medicinal Cameroonians plants and Acute toxicity of hydroethanolic extract of Vitellaria paradoxa

Tuberculosis (TB) is an infectious disease caused by the Mycobacterium tuberculosis (M. tuberculosis) complex, resposible  for health problems in developing countries. In Africa, various medicinal plants are traditionally used to treat  TB.  The aim of this study is to carry out the phytochemical screening, to evaluate the antimycobacterial activity of the crude extracts of three medicinal plants present in Cameroon (Zingiber officinale, Vitellaria paradoxa and Alstonia boonei) and the acute toxicity of hydroethanolic extract of Vitellaria paradoxa. The phytochemical screening was obtained by hydroethanolic extraction  and decoction. Inhibitory parameters of antimycobacterial activities were determined using the microplate alamar blue assay against M. tuberculosis H37Rv (ATCC 27294) and on one M. tuberculosis clinical strain. The crude extract with the best antimycobacterial activity was used for the acute toxicity assessment according to the OECD protocol. The results of the phytochemical screening revealed the presence of triterpenes and steroids in all the extracts, whereas  phenols were only present in the decoction of Alstonia boonei. All extracts tested showed antimycobacterial activities. The hydroethanolic extract of V. paradoxa  presented the best antimycobacterial activity with MICs of 78.13 and 625 μg/mL and MBCs of 78.13 and 2500 μg/mL respectively on M. tuberculosis H37Rv and on M. tuberculosis clinical strain. The results of the acute toxicity evaluation of V. paradoxa  showed a lethal dose 50  greater than 5000 mg/kg compared to control. The antimycobacterial activity of all the plant extracts used in this study justifies the traditional use of these medicinal plants on the treatment of  TB. Keywords: Zingiber officinale, Vitellaria paradoxa, Alstonia boonei, Phytochemical screening, Antimycobacterial activity, Acute toxicity

Effects Of Essential Oil From Drypetes gossweileri S. Moore Stem Barks On Cell Release And Dna Synthesis Of Mycobacterium tuberculosis

Background: In the recent years, the proliferation of multi-drug-resistant and extensively drug-resistant strain to tuberculosis (TB) suggest that efforts are required to find alternative treatments. The designed study aimed to show the effects of essential oils (EO) from Drypetes gossweileri stem barks on Mycobacterium tuberculosis cell membrane release and DNA synthesis. Methods: The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined against two clinical isolates (IS53 and IS310) and the reference strain H37Rv ATCC 27294 using microdilution method. The effect of essential oil on cell membrane release of Mycobacterium tuberculosis was evaluated by measuring DNA, RNA and proteins release in extracellular medium using NanoDrop 1000 spectrophotometer to show the membrane integrity lose. The effect on DNA was performed by measuring genomic DNA and amplicons of MIRU 04 sequence produced when treated at MICs and MBCs concentrations to put in evidence the inhibitory effect of EO during DNA synthesis. Results: The results revealed that EO from Drypetes gossweileri stem barks exhibited strong activity with MIC ranging from 4.88 µg/mL against H37Rv and IS310 to 9.76 µg/mL against IS53. The significant release of DNA, RNA and proteins in extracellular medium were observed for treated cells at MIC and MBC concentrations compare to untreated cells. The most quantified biomolecules were proteins with concentration ranging from 370.9 104 ng/µL to 10630.0 104 ng/µL released at MIC concentration which increased from 1890.0 104 ng/µL to 12000.9 104 ng/µL at MBC. The inhibitory effect of DNA synthesis by EOs enhanced lower quantity of DNA for all treated cells at MIC and MBC compare to untreated cells. The results obtained in this study enabled the identification of two cellular targets (cell membrane and DNA) of EO from D. gossweileri stem barks on M. tuberculosis

Mycobacterium tuberculosisis the causative agent of tuberculosis in the southern ecological zones of Cameroon, as shown by genetic analysis

BACKGROUND: Tuberculosis (TB) is a major cause of mortality and suffering worldwide, with over 95% of TB deaths occurring in low- and middle-income countries. In recent years, molecular typing methods have been widely used in epidemiological studies to aid the control of TB, but this usage has not been the case with many African countries, including Cameroon. The aims of the present investigation were to identify and evaluate the diversity of the Mycobacterium tuberculosis complex (MTBC) isolates circulating in two ecological zones of Cameroon, seven years after the last studies in the West Region, and after the re-organization of the National TB Control Program (NTBCP). These were expected to shed light also on the transmission of TB in the country. The study was conducted from February to July 2009. During this period, 169 patients with symptomatic disease and with sputum cultures that were positive for MTBC were randomly selected for the study from amongst 964 suspected patients in the savannah mosaic zone (West and North West regions) and the tropical rainforest zone (Central region). After culture and diagnosis, DNA was extracted from each of the MTBC isolates and transported to the BecA-ILRI Hub in Nairobi, Kenya for molecular analysis. METHODS: Genetic characterization was done by mycobacterial interspersed repetitive unit–variable number tandem repeat typing (MIRU-VNTR) and Spoligotyping. RESULTS: Molecular analysis showed that all TB cases reported in this study were caused by infections with Mycobacterium tuberculosis (98.8%) and Mycobacterium africanum (M. africanum) (1.2%) respectively. We did not detect any M. bovis. Comparative analyses using spoligotyping revealed that the majority of isolates belong to major clades of M. tuberculosis: Haarlem (7.6%), Latin American-Mediterranean (34.4%) and T clade (26.7%); the remaining isolates (31.3%) where distributed among the minor clades. The predominant group of isolates (34.4%) corresponded to spoligotype 61, previously described as the “Cameroon family. Further analysis based on MIRU-VNTR profiles had greater resolving power than spoligotyping and defined additional genotypes in the same spoligotype cluster. CONCLUSION: The molecular characterization of MTBC strains from humans in two ecological regions of Cameroon has shown that M. tuberculosis sensu stricto is the predominant agent of TB cases in the zones. Three decades ago, TB was reported to be caused by M. africanum in 56.0% of cases. The present findings are consistent with a major shift in the prevalence of M. tuberculosis in Cameroon

Mycobacterium tuberculosis complex drug resistance pattern and identification of species causing tuberculosis in the West and Centre regions of Cameroon

<p>Abstract</p> <p>Background</p> <p>Data on the levels of resistance of <it>Mycobacterium tuberculosis </it>complex (MTBC) strains to first line anti-tuberculosis drugs in Cameroon, and on the species of MTBC circulating in the country are obsolete. The picture about 10 years after the last studies, and 6 years after the re-organisation of the National Tuberculosis (TB) Control Programme (NTBCP) is not known.</p> <p>Methods</p> <p>The study was conducted from February to July 2009 in the West and Centre regions of Cameroon. A total of 756 suspected patients were studied. MTBC species were detected by the standard Ziehl-Neelsen staining method. Bacterial susceptibility to the first line drugs [isoniazid (INH), rifampicin (RIF), ethambutol (EMB) and streptomycin (SM)] were performed on cultures using the indirect proportion method. MTBC species were identified by standard biochemical and culture methods.</p> <p>Results</p> <p>Of the 756 suspected patients, 154 (20.37%) were positive by smear microscopy. Of these, 20.77% were HIV patients. The growth of <it>Mycobacterium </it>was observed with the sputa from 149 (96.75%) subjects. All the isolates were identified as either <it>M. tuberculosis </it>or <it>M. africanum</it>. Among these, 16 (10.73%) were resistant to at least one drug (13.3% for the West region and 8.1% for the Centre). The initial resistance rates were 7.35% for the Centre region and 11.29% for the West region, while the acquired resistance rates were 16.66% (1/6) for the Centre region and 23.07% (3/13) for the West. Within the two regions, the highest total resistance to one drug was obtained with INH and SM (2.68% each). Multidrug-resistance (MDR) was observed only in the West region at a rate of 6.67%. No resistance was recorded for EMB.</p> <p>Conclusions</p> <p><it>M. tuberculosis </it>and <it>M. africanum </it>remain the MTBC species causing pulmonary TB in the West and Centre regions of Cameroon. Following the re-organisation of the NTBCP, resistance to all first line anti-TB drugs has declined significantly (<it>p </it>< 0.05 for West; and <it>p </it>< 0.01 for Centre) in comparison to previous studies. However, the general rates of anti-TB drug resistance remain high in the country, underscoring the need for greater enforcement of control strategies.</p

Portage vaginal et profil de sensibilité du Streptocoque du Groupe B Chez la femme enceinte à l'Hopital Gynéco-Obstétrique et Pédiatrique de Yaoundé (Yaoundé)

In order to obtain reliable data on vaginal carriage of Streptococcus agalactiae in pregnant women and to formulate a prevention program of neonatal Group B Streptococcus (GBS) disease, we carried out a prospective cross sectional study for 6 months. The general objective of the study was to evaluate the prevalence of vaginal carriage and the resistance profile of GBS. The study involved 142 pregnant women presenting for antenatal care in Yaoundé Gynecology-Obstetric and Pediatric Hospital (YGOPH). Participants were interviewed using a standard structure questionnaire. Low vaginal swabs were collected and cultured on specific media. A presumptive identification of isolates was made using standard bacteriological methods. Confirmative identification of Group B Streptococcus was done and antimicrobial sensitivity testing was performed. Among the 142 pregnant women GBS colonization was confirmed in 11 (7.7%). The rate of carriage was 3.8% in the first trimester, 7% in the second trimester and 11.1% in the third trimester. The predominant germ was Candida albicans with a frequency of 45.2% among the germs found in monomicrobial culture and Gardnerella vaginalis (77.8%) among the germs in polymicrobial culture, followed by Candida spp (11.8%), S. agalactiae (8.6%) and Escherichia coli (4.3%). The result of antimicrobial sensitivity testing showed that all the GBS strains were sensitive to major antibiotics drugs tested. The highest rates of resistance were found with gentamycin (100%) and Cefuroxim (81.8%). The vaginal carriage of GBS among pregnant women is still high. Thus, well-planned, prospective studies will be necessary to fully appreciate the magnitude of the problem of GBS in our hospitals

Strong decrease in streptomycin-resistance and absence of XDR 12 years after the Reorganization of the National Tuberculosis Control Program in the Central Region of Cameroon.

BACKGROUND: In the 1990s, resistance rates of 15% for streptomycin-resistance and 0.6% for multidrug-resistance (MDR) were reported from the Central Region of Cameroon. This work assesses drug resistant tuberculosis in this region 12 years after reorganization of the National Tuberculosis Control Program (NTCP). METHODS: This cross-sectional study was conducted from April 2010 to March 2011 in Jamot Hospital in Yaoundé, Cameroon. Only patients with smear positive pulmonary tuberculosis were included. Sputa were cultured and subsequently underwent drug susceptibility testing (DST). All consenting individuals were tested for their HIV status. RESULTS: A total of 665 smear positive pulmonary tuberculosis patients were enrolled. The HIV prevalence was 28.5% (95%CI [25.2-32.1]). Of the 582 sputa that grew Mycobacterium tuberculosis complex species, DST results were obtained for 576. The overall resistance rate was 10.9% (63/576). The overall resistance rates for single drug resistance were: isoniazid-resistance 4.7% (27/576), streptomycin-resistance 3.3% (19/576), rifampicin-resistance 0.2% (1/576), kanamycin-resistance 0.2% (1/576) and ofloxacin-resistance 0.2% (1/576). The MDR rate was 1.1% (6/576) and no extensively drug resistant tuberculosis (XDR) was detected. CONCLUSIONS: The data show that reorganization of the NTCP resulted in a strong decrease in streptomycin-resistance and suggest that it prevented the emergence of XDR in the Central Region of Cameroon

Effect of Fractioning on Antibacterial Activity of Enantia chlorantha

Infectious diseases caused by bacteria constitute the main cause of morbidity and mortality throughout the world and mainly in developing countries. In this work, the influence of fractioning and the mode of action of stem barks methanol extract of Enantia chlorantha were investigated. The aim was to optimize the antibacterial activity of the methanol extract. The extract was prepared by maceration of barks powder in methanol. Fractioning was done using increasing solvents polarity. Standard phytochemical methods were used for phytochemical screening. Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentration (MBC) of the methanol extract and fractions were determined using broth microdilution method. The studied mode of action of both methanol extract and n-butanol fraction included antibiofilm activity, H+-ATPase-mediated proton pumping assay, salt tolerance, and cells cycle. The methanol extract of E. chlorantha stem barks was found to be active on all the bacteria tested (32 ≤ MIC ≤ 512 μg/mL), its activity being significant (MIC < 100 μg/ml) out of 5 of the 28 clinical isolates used. Salmonella enterica serovar paratyphi A was the most sensitive (32 μg/mL). Compared to the extract and other fractions, the n-butanol fraction was found to be more active (32 ≤ MIC ≤ 256). Significant antibacterial activity of this fraction was observed out of 10 of the 28 bacterial isolates and 3 out of 7 bacterial strains. Lowest MIC values (32 μg/ml) of this fraction were obtained with Escherichia coli (136), Pseudomonas aeruginosa (CIP 76110), and Salmonella enterica serovar typhi 9. The methanol extract of E. chlorantha and its n-butanol fraction revealed several modes of action including the prolongation of the latency phase of the bacterial growth, the inhibition of the pump with protons H+ - ATPases bacterial, the loss of the salt tolerance of the Staphylococcus aureus, and inhibition of the formation of the bacterial biofilm. The present results showed that the n-butanol fraction of the methanol stem barks extract of E. chlorantha possess the essential antibacterial components and could best be used to fight against bacterial infections as compared to methanol extract

Study population in Jamot hospital, CANTAM survey, Cameroun, 2010–2011.

<p>Study population in Jamot hospital, CANTAM survey, Cameroun, 2010–2011.</p