The genetic population structure of Mycobacterium bovis strains isolated from cattle slaughtered at the Yaoundé and Douala abattoirs in Cameroon

Bovine tuberculosis is still prevalent and under-evaluated in cattle destined for human consumption in Cameroon. Potential reservoirs of the disease include livestock imported from countries endemic for bovine tuberculosis, such as Nigeria and Chad, and potential residual reservoirs in local livestock and wildlife. Few studies have been done in Cameroon to genotype the Mycobacterium tuberculosis complex (MTC) strains responsible for bovine tuberculosis. The aim of this work is to describe the population structure of MTC strains isolated from cattle, using spoligotyping as the genotyping method. Out of 218 organs or tissues from cattle with suspected tuberculosis lesions, 90 MTC strains were isolated and underwent molecular typing; among them, 86 strains were identified as M. bovis and four strains as M. tuberculosis. The M. tuberculosis strains belonged to rare M. tuberculosis lineages of the U family; among the M. bovis strains SB0944 was the most prevalent. Eight new spoligotype patterns were identified, representing 33% (30/90) of all isolates. Among these new spoligotypes, SB1955 was dominant. The spoligotype patterns of 85 M. bovis strains lacked spacer 30, a common characteristic of the M. bovis lineage African 1, described earlier in Cameroon, Chad, Mali and Nigeria. This study shows ongoing tuberculosis transmission involving M. bovis lineages not previously described as the leading cause of disease. It also shows a possible reverse zoonosis from humans to cattle.

No Association between CagA- and VacA-Positive Strains of Helicobacter pylori and Primary Open-Angle Glaucoma: A Case-Control Study

INTRODUCTION

Glaucoma is a public health issue worldwide, particularly in Africa. In Cameroon, the prevalence rate of primary open-angle glaucoma (POAG) ranges between 4.5% and 8.2%. Helicobacter pylori (HP) has been implicated in digestive and extra-digestive diseases, including glaucoma. The objective of this work was to evaluate the implication of CagA- and VacA-positive strains of HP in POAG using a case-control design.

METHODS

An analytical study was conducted from October 2013 to December 2013. Participants were recruited in eye care centers in Yaoundé. Enzyme-linked immunosorbent assays (ELISAs) were carried out in the La Grace Laboratory in Yaoundé.

RESULTS

The total sample consisted of 50 POAG patients and 31 controls with a mean age of 58.5 ± 12.2 years and 45.5 ± 14.6 years, respectively. The prevalence rates of HP in the POAG and control groups were 74% (37/50) and 87% (27/31), respectively (P = 0.125). The prevalence rates of CagA-positive HP seropositivity in the POAG and control groups were 26% and 22.58%, respectively (P = 0.47), and the prevalence rates of VacA-positive HP participants were 6% and 0%, respectively (P = 0.22).

CONCLUSION

The HP prevalence rates among POAG patients and controls were 74% and 87%, respectively. There was no significant difference between prevalence rates of HP in the POAG and control groups. There was no association between POAG and CagA- or VacA-positive HP infection.

Toxicological evaluation of ethyl acetate extract of Cylicodiscus gabunensis stem bark (Mimosaceae)

The toxicity profile of the ethyl acetate (EA) extract of the stem bark of Cylicodiscus gabunensis (CG) was studied in Wistar rats. The rats were administered graded doses (0.75, 1.5, 3 and 6 g/kg p.o.) of the extract daily for 6 weeks and the effects on clinical signs, body weight, food and water consumption, organ weight, haematology, histology as well as serum, hepatic and renal biochemical parameters were measured. Body weight of dosed and control rats increase throughout the duration of treatment but food and water consumption were not significantly affected. The relative weights of the liver, lungs, heart and kidneys remained normal whereas a significant change was observed in that of the spleen. The hematocrit level was increased in treated animal. Our data demonstrates a significant increase in serum concentrations of aspartate amino-transferase, alanine amino-transferase, total cholesterol and glucose with high-dose of CG treatment tested (3-6 g/kg). CG also caused a significant reduction in hepatic malondialdehyde concentration. Renal urea and creatinine levels were reduced significantly in test groups. Histological findings reveal a characteristic progression treatment-related effect on liver, kidneys and lungs. The acute toxicity LD50 was estimated at 14.5 and 11 g/kg body weight (b.w.) for male and female respectively, but dose-related mortality of 30 and 50% were observed during the sub-acute toxicity. These findings have once more highlighted the limitations of the acute toxicity LD50 testing and suggest that CG may exert varied toxicological effects when administered orally in rats.

In Vitro antifungal activity of extract and plumbagin from the stem bark ofDiospyros crassiflora Hiern (Ebenaceae)

In this study the methanol/dichloromethane (1:1) extract and plumbagin isolated from extract of stem barks of Diospyros crassiflora were tested for their antifungal activity against 12 strains of yeast pathogens and filamentous fungi: Candida albicans, Candida glabrata, Candida krusei, Candida tropicalis, Cryptococcus neoformans, Aspergillus niger, Aspergillus flavus, Alternaria sp., Cladosporium sp., Geotrichum candidum, Fusarium sp. and Penicillium sp. The growth of all fungi strains tested was inhibited by the extract and plumbagin. The diameter of inhibition zones varied from 12 to 18 mm and from 21 to 35 mm for the extract and plumbagin, respectively. The MIC values ranged from 12.5 to 25 mg/mL for the extract and 0.78-3.12 microg/mL for plumbagin. It is therefore suggested that extracts from the stem bark of Diospyros crassiflora could be used traditionally in the treatment of fungal infections. Compared with ketoconazole used as a standard antifungal, plumbagin could be considered as a promising antifungal agent.

Evaluation of antimicrobial activity of the stem bark of Cylicodiscus gabunensis (Mimosaceae)

Ethyl acetate (EA) extract of the stem bark of Cylicodiscus gabunensis (CG) was analysed phytochemically and evaluated for its antimicrobial activity against 17 pathogenic species isolated from patient: Escherichia coli, Klebsiella pneumoniae, Shigella dysenteriae, Shigella flexneri, Morganella morganii, Proteus vulgaris, Proteus mirabilis, Salmonella typhi, Citrobacter freundii, Enterobacter cloacae, Enterobacter agglomerans, Staphylococcus aureus, Streptococcus feacalis, Pseudomonas aeruginosa, Bacillus cereus T, Candida albicans and Candida glabrata. Flavonoids, saponins, tannins, polyphenols, coumarins, triterpenes and/or sterols and reducing sugars were detected in the (EA) extract of CG. The best MIC and MBC values for the microorganisms sensitive to the extract were 0.00078 and 0.00315 mg/ml respectively. The greater and remarkable antimicrobial activity of the (EA) extract of CG was recorded with Staphylococcus aureus, Proteus vulgaris and Bacillus cereus T. These results provide a rationalization for the traditional use of this plant for the treatment of infectious diseases.