EFFICACY OF ANTIMICROBIAL ACTIVITY OF GARLIC EXTRACTS ON BACTERIAL PATHOGENS COMMONLY FOUND TO CONTAMINATE MEAT.

BACKGROUND: Meat is amajor source of food and raw materials for a number of industries, yet a lot of meat is wasted each year due to deterioration as a result of spoilage by microorganisms such as Pseudomonas, Acinetobacter, Moraxella, Bacillus, Campylobacter, Escherichia, Listeria, Clostridium, Salmonella and Staphylococcus species. OBJECTIVE: To determine efficacy of antimicrobial activity of garlic extracts on bacterial pathogens commonly found to contaminate meat. DESIGN: A cross sectional study. SETTING: The Department of Public Health, Pharmacology and Toxicology, Faculty of Veterinary Medicine University of Nairobi. SUBJECTS: Garlic from Nganoini farm in Laikipia County, Kenya. RESULTS: The results indicated that garlic absolute ethanol extract had the highest efficacy of antimicrobial activity inhibiting all test micro-organisms. CONCLUSION: Ethanolic extract can be used as a meat preservative or decontaminant.

Atypical dermatophilosis of sheep in Kenya.

An outbreak of an atypical form of ovine dermatophilosis affecting the lips and muzzle with a very high morbidity in weaners and hoggets in Kenya is reported. Clinical diagnosis of ovine dermatophilosis was made and confirmed by direct microscopic examination as well as isolation and identification of Dermatophilus congolensis from scab material from the affected sheep. The morbidity rate within the flock was 31.8% (237/745) with 98.3% (233/237) of the affected sheep being weaners and hoggets. No fatalities were recorded. The lesions, confined in the lips and the muzzle, were swelling of both the upper and lower lips, circumscribed lumps in the skin of both the upper and lower lips, oedema of the head and the submandibular area and scabs and crusts on the lips and muzzle. Within 1 week following treatment with long acting oxytetracycline (20%) at a rate of 20 mg/kg body weight, intramuscularly and a topical application of oxytetracycline spray, lumps regressed in size and were covered by dark-brown scabs. Removal of the dark-brown scabs revealed erythematous areas covered with purulent material and horny erythematous projections (papillae) projecting from the surfaces. Within the 2nd week, the horny erythematous projections formed greyish scabs, which later peeled off leaving alopaecic areas around the lips. The paper highlights atypical dermatophilosis of sheep and we believe that this is the first published report of an outbreak of ovine dermatophilosis in Kenya.

Immunoassay and polymerase chain reaction techniques for detection of enterotoxigenic Bacillus cereus.

OBJECTIVES: To compare the Reverse Passive Latex Agglutination (RPLA) and Enzyme Linked Immunosorbent Assay (ELISA) techniques with a Polymerase Chain Reaction (PCR) for detection of enterotoxigenic Bacillus cereus. DESIGN: A cross-sectional study. SETTING: The Department of Public Health, Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Nairobi. SUBJECTS: Forty seven Bacillus cereus strains previously isolated from foods. MAIN OUTCOME MEASURES: Detection of hemolysin BL, non-hemolytic enterotoxin, binding protein gene (hblA) of the hemolysin BL, and binding protein gene (nheA) of nonhemolytic enterotoxin. RESULTS: Twenty five (53.2%) of the isolates produced hemolysin BL, while 81% of them produced non-hemolytic enterotoxin. Thirty eight (38.3%) produced both hemolysin BL and non-hemolytic enterotoxin. A polymerase chain reaction amplification assay detected the presence of hblA gene in all hemolysin BL positive isolates and nheA gene in 91.5% of non-hemolytic enterotoxin positive isolates. There was a strong association between PCR test and RPLA test (Pearson's X2 = 12.65; p < 0.001) as well as between PCR test and visual immunoassay test (Pearson's chi-square X2 = 18.46: p < 0.01). CONCLUSION: Polymerase chain reaction amplification assay technique for detection of enterotoxigenicity of B. cereus compare well with the immunoassay tests. The technique is sensitive detecting even strains with silentgenes, and is rapid with the test complete within 24 hours.

Prevalence of enterotoxigenic Bacillus cereus and its enterotoxins in milk and milk products in and around Nairobi.

OBJECTIVES: To determine the prevalence of enterotoxigenic Bacillus cereus (B. cereus) and enterotoxins in milk and milk products. DESIGN: A random sampling of milk products was carried out. SETTING: Market milk and milk products were collected from retail shops in Nairobi and analysed for contamination with enterotoxigenic B. cereus and its enterotoxins using reverse passive latex agglutination and TECRA ELISA immunoassay tests. SUBJECTS: Ninety six milk samples including 36 raw milk, 42 pasteurised milk, 10 yogurt and eight fermented milk samples. Forty seven Bacillus cereus isolated from milk and milk products. MAIN OUTCOME MEASURES: Isolation of enterotoxigenic B. cereus from milk and milk products and detection of B. cereus hemolytic (hemolysin BL) and non-hemolytic enterotoxins in milk. RESULTS: Fifty seven percent of the samples were contaminated with B. cereus. Eighty one percent (38 out of 47) of the isolates produced non-hemolytic enterotoxins, while 25 (53.2%) of the isolates produced hemolysin BL. Eighteen (38.3%) of the isolates produced both hemolysin BL and non-hemolytic enterotoxins. About fourteen percent (14.3%) of the pasteurised milk samples tested positive for non-hemolytic enterotoxin. CONCLUSION: Enterotoxigenic B. cereus and enterotoxins occur in market milk and their presence poses a potential risk of causing food poisoning. The risk can be reduced if milk products undergo thorough quality control checks and are always kept at below 4 degrees C till consumption. Post pastuerisation contamination which is commonly blamed for spoilage of milk products by B. cereus is not necessarily the most important source of this organism.

Antimicrobial resistance patterns and plasmid profiles of Staphylococcus aureus isolated from milk and meat.

OBJECTIVES: To determine the frequency of resistance of Staphylococcus aureus to various antimicrobial agents, and the relationship between antimicrobial resistance of the isolates and carriage of plasmids. DESIGN: A random sampling of milk and meat samples was carried out. SETTING: Milk was collected from various dairy co-operative societies in Nairobi and Kiambu districts. Minced meat samples were purchased from various outlets in the city of Nairobi. SUBJECTS: Ninety six Staphylococcus aureus isolates from milk (seventy five isolates) and minced meat (twenty one isolates) samples. MAIN OUTCOME MEASURES: Plasmid profiles and antimicrobial susceptibility tests to ampicillin, lincomycin, penicillin, erythromycin, methicillin, minocycline, cotrimoxazole and chloramphenicol. RESULTS: Seventy one per cent of the isolates carried between one and six plasmids of molecular sizes ranging from 0.1 to 14.5 kilobases. High frequency of resistance was observed with lincomycin (67.7%), penicillin (66.7%) and cotrimoxazole (51%). A high percentage (76%) of isolates were susceptible to minocycline followed by erythromycin (57.3%). Most (80.2%) of isolates were multiply resistant to between two and six antibiotics. CONCLUSION: Most Staphylococcus aureus isolates were multiply resistant to various antimicrobial agents, but there was no apparent relationship between carriage of plasmids and antimicrobial resistance. Milk and meat may contain resistant Staphylococcus aureus posing a potential risk to consumers.

An outbreak of urticarial form of swine erysipelas in a medium-scale piggery in Kiambu District, Kenya.

This report concerns an outbreak that occurred during July/August 1997. Ten pigs from a herd of 181 pigs in a medium-scale, semi-closed piggery in Kiambu District, Kenya, contracted the clinical disease. The main clinical findings in affected pigs included: fever (40.5-41.8 degrees C), prostration, inappetence, dog-sitting posture, abortion, erythema and raised, firm to the touch and easily palpated light pink to dark purple diamond-shaped to square/rectangular spots on the skin around the belly and the back. Based on the pathognomonic skin lesions, a clinical diagnosis of swine erysipelas was made. The diagnosis was confirmed by the isolation of Erysipelothrix rhusiopathiae organisms from the blood and skin biopsies taken from the affected pigs. Response to treatment with a combination of procaine penicillin and dihydrostreptomycin at the dosage rate of 20,000 IU/kg body weight (based on procaine penicillin) for 3 days was good and all the affected pigs recovered fully. The farm was placed under quarantine to prevent spread of the disease.