Efficacy of antimicrobial activity of garlic extracts on bacterial pathogens commonly found to contaminate meat

Background: Meat is a major 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, KenyaResults: 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

Antimicrobial resistance of Campylobacter isolates from small scale and backyard chicken in Kenya

Background Thermophilic Campylobacter species are a major cause of bacterial foodborne diarrhoea in humans worldwide. Poultry and their products are the predominant source for human campylobacteriosis. Resistance of Campylobacter to antibiotics is increasing worldwide, but little is known about the antibiotic resistance in Campylobacter isolated from chicken in Kenya. In this study, 35 suspected Campylobacter strains isolated from faeces and cloacal swabs of chicken were tested for their susceptibility to seven antibiotics using a broth microdilution assay and molecular biological investigations. Results Overall, DNA of thermophilic Campylobacter was identified in 53 samples by PCR (34 C. jejuni, 18 C. coli and one mix of both species) but only 35 Campylobacter isolates (31 C. jejuni and 4 C. coli) could be re-cultivated after transportation to Germany. Isolates were tested for their susceptibility to antibiotics using a broth microdilution assay. Additionally, molecular biological detection of antibiotic resistance genes was carried out. C. jejuni isolates showed a high rate of resistance to nalidixic acid, tetracycline and ciprofloxacin of 77.4, 71.0 and 71.0 %, respectively. Low resistance (25.8 %) was detected for gentamicin and chloramphenicol. Multidrug resistance in C. jejuni could be detected in 19 (61.3 %) isolates. Resistance pattern of C. coli isolates was comparable. Resistance to ciprofloxacin was confirmed by MAMA–PCR and PCR–RFLP in all phenotypically resistant isolates. The tet(O) gene was detected only in 54.5 % of tetracycline resistant C. jejuni isolates. The tet(A) gene, which is also responsible for tetracycline resistance, was found in 90.3 % of C. jejuni and in all C. coli isolates. Thirteen phenotypically erythromycin-resistant isolates could not be characterised by using PCR–RFLP and MAMA–PCR. Conclusions To the best of our knowledge, this study is the first report about resistance to antibiotics in thermophilic Campylobacter originating from chicken in Kenya. Campylobacter spp. show a high level of resistance to ciprofloxacin, nalidixic acid and tetracycline but also a remarkable one to chloramphenicol and gentamicin and they are multidrug resistant. Resistance to antibiotics is a global public health concern. In Kenya, resistance surveillance needs further attention in the future. Efforts to establish at least a National Laboratory with facilities for performing phenotypic and genotypic characterization of thermophilic Campylobacter is highly recommended

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 isolatesand 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 aureusposing a potential risk to consumers

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°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. East African Medical Journal Vol.82(6) 2005: 280-28

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:

Genetic Basis, Transferability And Linkage Of Streptomycin And Sulphonamide Resistance Genes In Escherichia Coli From Food Animals In Kenya

The genetic basis and transferability of streptomycin and sulphonamide resistance was studied in 23 Escherichia coli isolates from food animals in Kenya. Physical linkage of the streptomycin resistance gene strA with sulphonamide resistance gene sul2 was investigated by PCR and confirmed by sequencing. Two small plasmids of 6 kb (pSSGK1) and 8 kb, (pSSTGK1) identified by transformation to mediate resistance to at least streptomycin and sulphonamide were restricted in order to define their relatedness. Their restriction maps were compared to one another and with the maps of other plasmids from E. coli known to mediate these resistance properties. Streptomycin resistance was based on the expression of the strA, strB and/or aadA1 genes, while sulphonamide resistance was encoded by the sul2 or sul1 gene. The strA, strB and sul2 genes were transferable via conjugation and transformation. Physically linked sul2 and strA genes were present in both plasmids pSSGK1 and pSSTGK1. The plasmids pSSGK1 and pSSTGK1 were different from each other, but similar respectively to sulphonamide/streptomycin and sulphonamide/streptomycin/tetracycline resistance plasmids described previously in uropathogenic E. coli from humans. Conjugation of plasmids encoding streptomycin and sulphonamide resistance may be one mechanism for the wide dissemination and persistence of these resistances among food animal E. coli in Kenya. Physical linkage of the plasmid-borne strA and sul2 genes would facilitate the spread of these genes by co-selection during selective pressure imposed by the use either of the two antimicrobials and highlights the need for the prudent use of streptomycin or sulphonamides in animal husbandry.La base génétique et la transférabilité de la résistance à la streptomycine et au sulfamide ont été étudiées chez 23 souches de Escherichia coli issues d'aliments d'origine animale au Kenya. Le lien physique du gène strA de résistance à la streptomycine avec le gène sul2 de résistance au sulfamide a été examiné par PCR et confirmé par séquençage. Deux petits plasmides de 6 kb (pSSGK1) et de 8 kb (pSSTGK1) identifiés par transformation pour modifier la résistance au moins à la streptomycine et au sulfamide étaient restreints en vue d'établir leur lien. Leurs cartes de restriction étaient comparées les unes aux autres ainsi qu'avec les cartes des autres plasmides issus de E. coli pour modifier leurs propriétés de résistance. La résistance à la streptomycine était fondée sur l'expression des gènes strA, strB et/ ou aadA1, alors que la résistance au sulfamide était codée par le gène sul2 ou sul1. Les gènes strA, strB et sul2 étaient transférables par le biais de conjugaison et de transformation. Les gènes sul2 et strA physiquement liés étaient présents dans les deux plasmides pSSGK1 et pSSTGK1. Les plasmides pSSGK1 et pSSTGK1 étaient différents l'un de l'autre, mais respectivement semblables aux plasmides de résistance au sulfamide/streptomycine et sulfamide/streptomycine/tétracycline décrits auparavant dans E. coli uropathogènes issus des humains. La conjugaison des plasmides codant la résistance à la streptomycine et au sulfamide peut être un mécanisme pour la large diffusion et la persistance de ces résistances dans E. coli issus des aliments d'origine animale au Kenya. Le lien physique des gènes strA et sul2 transportés par le plasmide pourrait faciliter la propagation de ces gènes par une co-sélection au cours de la pression sélective imposée par l'utilisation de l'un ou l'autre des deux agents antimicrobiens, et souligne la nécessité de recourir à l'usage judicieux de la streptomycine ou du sulfamide dans l'élevage.Bulletin of Animal Health and Production in Africa Vol. 56 (1) 2008: pp. 56-6