MST-Department of Microbiology

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Characterisation of natural immune responses to fal vac-l of plasmodium falciparumin children and adults from a holoendemic area of Western Kenya
(Kenyatta University, 2000) Were, Tom
Previous studies indicate that FAL VAC-1, a recombinant multistage and multicomponent Plasmodium falciparum candidate vaccine containing 12 B cell and 9 T cell epitopes from 9 different antigens of different life cycle stages is immunogenic in animal models and that FAL VAC-1-induced antibodies produced significant antiparasite activities against both sporozoite and blood stages of the parasite. In preparation for vaccine trials in humans, a community based cross-sectional study in a malaria holoendemic area of western Kenya was conducted during April-August 1999, to characterise in vitro natural humoral and cellular immune responses to this candidate vaccine and their association with clinical protection against malaria in young children < 2 years old (N= 180) and their non-pregnant mothers aged 15-48 years (N=139). FAL VAC-1 antigen was used in antibody measurement by ELISA and in lymphoproliferative experiments. Prevalence and level of antibodies were significantly higher in adults than in children when stratified by age groups: 0-6 months; 7-12 months, 13-18 months; 19-24 months; 15-25 years and 26-48 years. Total IgG, IgG1, IgG3 and IgM were the predominant antibodies. IgG2 responses were low and no IgG4 was detected. In children, there were higher IgG 1 levels in parasitaemic group than in the aparasitaemic 'group (F=3.459, p=0.024, t-test). Furthermore, total IgG, IgG1, IgG3 and IgM levels were inversely associated with .' . r '. haemoglobin levels at the time of sampling (total IgG, r=-0.215, p=0.005, IgG1, r=- 0.180, p=0.019; IgG3, r=-0.164, p=0.034; IgM, r=-0.216, p=O.OOl). Parasitaemic children had significantly higher IgG 1 levels at a month prior to sampling. In addition, IgG 1 was positively correlated to the rate of high density parasitaemia and to episodes of clinical malaria (r=0.218, p=0.029 and r=0.237, p=0.018), respectively. However, in adults, aparasitaemic individuals had high total IgG, IgG 1 and IgM levels than parasitaemic individuals (total IgG, F=3.856, p=O.007; IgGl, F=2.701, p=O.007; IgM, F=5.133, p=O.OOl,t-test). In addition, IgG2 was inversely associated with haemoglobin levels at the time of sampling. In contrast to antibody responses, lymphoproliferative responses were higher in children than in adults (one-way ANOV A, F=2.392, p=O.038). Generally, lymphocytes from adults responded at lower antigen concentrations, while those from children responded at higher antigen concentrations. There were no associations between lymphoproliferation and malaria infection or haemoglobin level in either young children or adults. The results of this study therefore indicate that: FAL VAC-l, a multistage multicomponent malaria vaccine candidate is recognised by individuals naturally exposed to malaria. The antibody responses increase whereas lymphoproliferative responses decrease with age. The higher IgG1 levels in children may indicate the presence of a current P. falciparum infection, but in adults from the same holoendemic area, IgG 1, may be associated with protection against parasitaemia.
Evolutionary relationship between Trypanosoma evansi and trypanosoma brucei with respect to specific mitochodrial antigen and phenotype knockout analysis
(Kenyatta University, 2005) Obanda, Benear Apollo
Trypanosomiasis is a disease caused by parasitic protozoans of the genus Trypanosoma. The agents of the disease are obligate extracellular parasites that occur in blood, cerebrospinal fluid and tissue fluids. Trypanosoma brucei causes sleeping sickness and agana in sub-Saharan Africa. Trypanosoma evansi causing surra is endemic in Asia, Middle East northern Africa including Northern Eastern Kenya. Salivarian trypanosomiasis is one of the most important and widespread diseases of domestic animals and man in the world. The causes of the re-emergence of this disease include widespread civil war, declining economies, reduced health financing and the dismantling of disease control programs. The current drugs in use are toxic and not effective because of drug resistance, hence, the need for developing new drugs. The study objective was to establish the evolutionary relationship between T brucei and Tevansi, with respect to cell differentiation life cycle specific antigens and phenotype knockout analysis. PCR was used to compare genes encoding mitochodrial protein of Tevansi IL 1695, Tevansi IL 1934 and Trypanosoma brucei rhodesiense IL2343. Plasmid construction, preparation of plasmid DNA was done using alkaline lysis method. Extraction and purification of plasmid was by QIAGENR plasmid protocol. Cell line of T evansi and T brucei for RNA interference experiments were established. Electroporation was by Gene-Pulse machine for generation of knockout phenotypes. Statistical analysis was by Student's t-test. Tevansi IL1695, Tevansi III934 and T b. rhodesiense IL2343 contain all the five genes for mitochodrial protein in their genomes. MP 48 and MP 52 RNA editing ligases genes were identified in Trypanosoma evansi. Specific RNA ligases MP 48 630 bp and MP 52 560bp primers were developed. These primers specifically identify T evansi, T brucei and T equiperdum from other organisms. Alignment of MP 48 and MP 52 gene sequences obtained in T evansi and T brucei show 100 % homology. Comparisons of MP 48 and MP 52 RNA ligase gene with data of closely related organisms available in Genbank® showed no significant homology with the RNA ligase sequences of TcruziREL and L. majorREL2 sp. nor with the available sequences ofLt RNA ligase. Multiple alignment of T evansi MP52 and MP 48 with related proteins show a perfectmatch with T brucei and near-perfect match of genes with data of closely related organisms available in Genbank. T evansi was able to use T7 promoter gene, to recognize bacteriophage T7 RNA polymerase and produce RNA polymerase that synthesize mRNA encoding Green fluorescent protein, that was observed as Green fluorescent Tievansi. Approximately 40% of original populations of both the species were killed due to RNA interference. There was no significant difference in the effect of RNA interference in Tbrucei Gutat 3.1 and 'Levansi Tansui 13, using Student's t-test twotailed, p> 0.05 at 95% confidence interval. These new sub genus specific primers can be used as a diagnostic tool for monitoring pathogenic Trypanozoon parasites in humans, domestic animal. The primers can also be used in epidemiological survey. The RNA interference analysis identified MP48 and MP 52 RNA editing ligases as a drug target for the development of novel therapeutics in treatment of sleeping sickness, nagana and surra.
Bacterial and rota viral causes of diarrhoea in children under 5 years and the genetic basis of antibiotic resistance
(2005) Ndung’u, Perpetual Wangui
Diarrhoea causes significant morbidity and mortality among children in Kenya. The Illness is caused by a variety of pathogenic organisms, some which are difficult to identify immediately. This results in the use of enormous amounts of antibiotics and as a result, some of the pathogens develop resistance. This study was carried out between June 2003 and January 2004 to investigate the main causes of diarrhoea in children below the age of five years. It also sought to evaluate the problem of antibiotic resistance among these isolates, the role of plasm ids in the resistance and how much of this resistance was transferable. A total of 402 sample stool samples were collected from Kenyatta National Hospital, examined macroscopically to determine the presence of blood, pus, or mucus \\ luch are an important lead in determining the causative agents. The specimens were cultured in general and specific media to isolate different bacteria. Biochemical tests were carried out on suspect colonies for proper identification followed by API 20E screening test. A total of 13 different genera of bacteria were isolated some of which were non-pathogenic. The three genera of pathogenic bacteria isolated including 389 /:".co/i, I 1 Salmonella spp., and 5 ,\'!7iy;,-,IIa spp. Two viral species, 8 rota vi ruses and 2 corona viruses, were isolated from the first 100 specimens. Antibiotic sensitivity tests [vcete carried out on the pathogenic isolates using the Kirby Bauer disc diffu ion method. ".".coli ATCC 25922 was used as control to test the potency of the antibiotics. A total of 12 commonly used antibiotics for treatment of Gram-negative bacteria were used for the sensitivity tests. Plasmid fingerprinting was carried out using Horizontal Agarose Gel Electrophoresis (HEG) on the Ii.coli isolates. In vitro conjugation experiments were also undertaken to determine possible transfer of resistance to Ecoli K 12 F- Na" that has no plasm ids. Results from sensitivity tests indicated multidrug resistance on all three pathogenic strains. The highest resistance was shown by E coli, where four isolates were resistant to II of the 12 antibiotics used. The order of resistance by E.coli was highest on Trill1ethoprim-sulphamethaxazole (89%), and lowest on ceftazidime (4.6%). Salmonella and Shigella showed similar resistance, with highest resistance shown on Trimethoprimsulphamethcprirn (906%), while nalidixic acid, ciprofloxacin and gentamicin were effective on all the isolates of bacterial pathogens isolated. In addition,· all Shigella isolates were sensitive to ceftazidime. The drug resistant Ecoli had plasmids ranging between 2.0 and 98 megadaltons (Mda). Conjugation experiments showed that the ability to transfer resistance phenotypes by the larger plasmids existed for ampicillin, ch loramphenicol and tetracycline. The presence of ciprofloxacin resistant E.coli raises serious concerns and hence need for its frequent monitoring. These results indicate that there is need for constant surveillance on all antibiotics used for treatment of diarrhoea in children and to sensitize the public on the proper use of antibiotics.
Low Cost Materials and Techniques for Production of Oyster (Pleurotus Ostreatus) Mushroom Spawn by Farmers
(Kenyatta University, 2013) Thuranira, S. G.
Mushroom cultivation in Kenya is an emerging sector with great potential but its production is still low. In 1997, the world mushroom production was over 5 million tons. During this period, Kenya produced only 500 tons compared to its potential of 100,000 tons. The situation has not changed much with production estimated at 700 tons in 2010. The low production was due to supply of costly spawn which varied in quality and use of expensive sterilisation techniques. Again, spawn is multiplied in sorghum and other grains which are also used as food by man creating undue competition with producers and escalated spawn prices. Spawn is also produced far from farms which might interfere with mycelia development and compounds the cost of transport. This study was aimed at developing a cheap and simple method of sterilising substrate and cleaning the inoculation bench, and to identify an alternative substrate for multiplying spawn other than food grains. Grains of sorghum, wheat, millet, Sudan and Columbus were soaked overnight to soften, washed with tap water and excess water drained. Calcium carbonate was added to modify pH and fifty grams of each grain placed in plates. Sorghum grain was sterilised by autoclaving, pressure cooking or steaming before inoculation was done with Oyster spawn from Kabete. Similarly, grains were autoclaved and inoculated with spawn from Kabete, JKUAT, Juja community, Organic farm and Chiromo. During inoculation, the bench was cleaned by five different methods which include; open bench, hood with no supplementation, hood supplemented with alcohol spray, hood supplemented with spray and spirit lamp and laminar flow. The inoculated plates were immediately sealed and laid in a complete randomized design in the incubator at 25°C. The number of plates contaminated, type of fungal contaminants by colour and the rate of mycelia spread were recorded. GenStat 8th Edition was used to analyse the results and mean separation carried out at 95% significant level to find out if methods of sterilisation can achieve different results. Two way ANOV A statistics was carried out to establish whether methods of cleaning the bench and grain substrates were different. There was no significant difference between autoclaving and pressure cooking methods of sterilisation (P:s 0.05), but steaming was different from the other two. Contamination was 48.1 % in steamed samples, 39% in pressure cooked and 38% in autoclaved. Methods of cleaning the inoculation bench were also different though laminar flow was not different from hood supplemented with alcohol and spirit lamp (P:S 0.05). High contamination was recorded in open air bench (51 %) and least in laminar flow (33%). Methods of sterilisation and cleaning the bench did not affect mycelia spread. Grass grains were also not significantly different from food grains. Green fungal contaminant was the most common; over 80% and white fungal contam inant was lowest, 10%. The results have shown that pressure cooker can sterilise substrate, wood hood clean the inoculation bench and grass grains used as spawn carrier material. The study recommends that farmers grow sorghum grass to produce spawn and use the straw for mushroom cultivation.
Impact of hospital wastewater to the spread of antibiotic resistance in Kisii level 5 hospital in comparison to Kisii University, Suneka WWTP and Riana River-Kisii County, Kenya
(2013-12-24) Nyauncho, P. O.; Nyamache, A. K.; Maingi, J.
A potential post-antibiotic era is a threat and even in future medical advances. The current worldwide increase in antimicrobial resistance continues to pose a challenge with the downward trend in the development of new antibiotics posing serious implications. Despite the wide use of antibiotics especially in Kisii County, there is little available data concerning the contribution of hospital wastewater to the spread of antibiotic resistance in bacteria. Due to increasing trends in drug resistance, this study aims at determining the antimicrobial resistance profile of bacterial -isolates from wastewater effluents from Kisii level 5 Hospital and Kisii University College. In addition, to carrying out antibiotic testing of commonly prescribed drugs on the bacteria related infections in Kisii level 5 hospital. A total of 384 wastewater samples will be collected during the time period of 8 am to 5pm from July to November from participating institutions. The samples will be transported in chilled cool-boxes to the laboratory at Kisii level 5 hospital for analysis. Bacterial isolation will done by use of specific selective media and confirmed by biochemical tests. Subsequently, antibiotic susceptibility testing will be performed using Kirby- Bauer disc diffusion technique and zone of inhibition measured in diameter. Zone of inhibition will be interpreted as sensitive, intermediate and resistant according to CLSI (clinical laboratory standards institute). Collected data will be analyzed by use of ANOVA test to determine whether there is significant difference in resistance of bacteria to antibiotics from the sampling sites
Prevalence of trichophyton, microsporum and epidermophyton species causing tinea capitis in children aged 3-14 years in Mathare informal settlement, Nairobi, Kenya
(2014) Moto, Jedidah Ndunge
Tinea capitis is a worldwide public health problem that affects children below 15 years of age and requires identification of the specific causative fungal agent. The hair and skin of the scalp are associated with symptoms and signs of inflammation and hair loss. Poor hygiene, low standards of living, sharing of hair devices or garment, climate conditions and overcrowding are some of the predisposing factors contributing to frequent transmission of the infection. Several previous studies have concentrated on symptomatic cases of Tinea capitis infection with limited studies in Kenya. However, no such study has been done in Mathare informal settlement despite the existence of predisposing factors such as low standards of living of the people in the area. This study therefore aimed at determining the prevalence of Tinea capitis infection and its significant risk factors in Mathare informal settlement in both symptomatic and asymptomatic cases. The study also aimed at determining the prevalence of Trichophyton, Epidermophyton and Microsporum species causing Tinea capitis infection among school going children in Mathare informal settlement, Nairobi. A total of 150 children were systematically and randomly sampled from five public primary schools in Mathare informal settlement. Skin scrapings specimens were collected and inoculated on potato dextrose agar. Fungal cultural characteristics were observed macroscopically (pigmentation formation), microscopically (microconidia or macroconidia formation) and Trichophyton species differentiated by use of biochemical tests. In addition, a structural questionnaire was administered to consenting children’s guardians and socio-demographic data collected. In a total of one hundred and fifty (150) children aged between 3-14 years consisting of 89 (59.3 %) males and 61 (40.7 %) females, 123 (82 %) were infected with Tinea capitis. The dermatophytes consisted of 61.3 % Trichophyton, 13.3 % Microsporum and 7.3 % Epidermophyton with infections occurring either singly (56 %), duo (38 %) or tripple coinfections (6 %). Males were most affected with socio-economic factors such as employment status of the parents and monthly income levels of the family significantly influencing infections (p<0.001). Other factors that significantly influenced the infection include; knowledge on ways of transmission of Tinea capitis (p<0.001), sharing of combs and towels (p<0.001), place of hair shaving (p = 0.037) and frequency of hair shaving (p = 0.02). The prevalence of the infection was higher in lower age groups than the upper age group of 12-14 years. These findings suggest that prevalence of Tinea capitis infection in the informal settlement of Nairobi is high. There is therefore a need to improve personal and community hygiene including the economic status of people living in the informal settlement.
Prevalence, susceptibility patterns and risk factors associated with Staphylococcus aureus presence in marketed milk and milk products within Nairobi city county, Kenya
(Kenyatta University, 2014-09-26) Macharia, John Macharia;
S. aureus is a major food-borne pathogen that poses a serious threat to our world today. In Kenya, with the continuous water shortage, proper sanitary conditions are not sufficiently met pre-disposing the community to S. aureus infections. One of the difficulties of controlling S. aureus food poisoning is that food can contain a very high population of the bacteria without being noticeably identified. It has been implicated that food-borne diseases represents one of the most widespread and overwhelming public health problems in poor resource settings. The increasing rate of multi drug resistant S. aureus has continued to pose a challenge to the I.:.r_, pharmaceutical farms and patients management. The aim of this study is therefore to establish the presence of S aureus in processed milk and milk products, to determine the susceptibility patterns of S. aureus on the various antimicrobials and to conduct risk assessment on specific milk food safety hazard. Laboratory work and analysis will be done from Kenyatta University's Laboratory as well as the Centre for Microbiology Research-KEMRl based in Kenyatta National Hospital. Data will be collected for a period of three months. A total of 334 samples will be collected for isolation of S. aureus. A loop-full of the samples will be streaked directly on Mannitol salt agar which will be used as a "elective and an indicator media. Suspected isolates will then be inoculated on blood agar and confirmed by biochemical tests; Catalase test, Coagulase test and Oxidase test respectively. To determine antimicrobial sensitivity test, a panel of selected antibiotics commonly used in empirical treatment of S aureus infections will be selected from different classes. The antibiotics will be: Ampicillin, Erythromycin, Vancomycin, Chloramphenicol, Tetracycline, Gentamycin, Methicillin and Ciprofloxacin. This study is necessary since the findings will suggest the possible antibiotics of choice to be used in empirical treatment of S. aureus infections. In addition, information generated from this research will also provide a basis upon which formulation of better policies regarding processed milk and milk products can be based on by policy makers by developing tools and evidence that allows risk assessments to be conducted in formal and informal markets. Results will be statistically analyzed by means of analysis of variance and Chi-square for the comparison of concentration means of the total counts to assess the level of contamination and sensitivity patterns. Levels of P >0.05 will be taken to be non-significant
Antimicrobial activity of some medicinal plants used by the Samburu community of Northen Kenya against selected bacterial and fungal pathogens.
(2014-11) Onyambu, Abuga Samwel
Medicinal plants form an integral social and cultural component, and sometimes the only alternative available treatment for health problems. Infectious diseases concern the whole world because they cause an estimated 98% of deaths in both children and adults in developing countries. The aim of the study is to determine ethnobotanical uses and the bioactivity of some medicinal plants used by the Samburu community against selected bacterial and fungal pathogens. This study evaluated both antibacterial and antifungal activity of the selected twenty two medicinal plants used by the Samburu community. An ethnobotanical survey was conducted and collected information from herbalists on their use in the treatment of various infectious diseases. Plants identification was done with assistant of a taxonomist from Kenyatta University. Voucher specimens were prepared and deposited at the Department of Plant Sciences herbarium. Methanolic plant extracts were screened using Kirby-Bauer disk diffusion technique against eleven strains of bacteria and fungi obtained from Centre for Microbiology Research at Kenya Medical Research Institute, Nairobi Kenya. They were either American Type Culture Collection (ATCC) or clinical isolates; Bacillus subtilis (clinical isolate), Staphylococcus aureus (ATCC 25923), Streptococcus pneumoniae (ATCC 28910), Escherichia coli (ATCC 25922), Vibrio cholerae (ATCC 27622), Shigella dysenteriae (ATCC 26988), Candida parapsilosis (ATCC 18310), Cryptococcus neoformans (ATCC 19310), Aspergillus jlavus (clinical isolate), Microsporum gypseum (clinical isolate), Trichophyton mentagrophyte (clinical isolate). Minimum inhibitory concentrations (MICs) were determined by measuring the diameter around the discs, while micro-dilution technique was used to determine the minimum bacteriocidal and fungicidal concentrations (MBCsIMFCs). Extracts of Acacia nilotica, Thylachium africanum and Loranthus acaciae produced high antibacterial and antifungal activity results of ~9-15 mm and 9.375 - 18.75 mg/ml as showed by the MICs and MBCslMFCs results. Screening for phytochemicals; tannins, saponins, flavonoids, cardiac glycosides, alkaloids, and terpenoids indicated presence at varying concentrations either high, moderate, low or absent. Significant difference of zones of inhibition means of all the strains was observed at P:S;0.05. Clear indications from the data obtained were that these plants extracts serve as an enormous source of untapped antimicrobial agents. This study recommended that the Samburu community should continuously be sensitized on sustainable use of medicinal plants and that they should give priority to domesticating the medicinal plants. Further studies on the biological properties, isolation and identification of active components in the plant parts used in this research in order to test specific antimicrobial activity was also recommended.
Efficacy of some medicinal plants used in various parts of Kenya in treating selected bacterial and fungal pathogens
(Kenyatta University, 2015) India, Jacqueline
Medicinal plants have been used since time immemorial to treat and prevent human ailments. WHO indicates that up to 80% of the world's population uses traditional medicine. Infections caused by bacteria and fungi have become a major health problem globally accounting for over 50,000 deaths every day. It is estimated that more than 70% of the pathogenic bacteria are resistant to at least one of the antibiotics commonly used to treat them. Conventional drugs are expensive and have side effects. Many plants have been used by various communities in Kenya in the treatment of bacterial and fungal infections but they have not been validated. The main aim of this study was to determine the efficacy of some medicinal plants used by various communities in Kenya that treat the selected bacterial and the selected fungal diseases in man. An ethnobotanical survey was used to select and collect plants from Mwingi North, Kisii South and Rarieda Districts based on their use to treat infectious diseases such as skin infection, diarrhea and many others. Crude extracts from Zanthoxylum chalybeum, Boscia angustifolia, Melia volkensii, anthoxylum gilletii, Fuerstia africana, Urtica dioica, Vernonia amygdalina, Ricinus communis, Commiphora africana, Psidia puntulata, Senna didymobotrya, Ormocarpum trichocarpum, Sesbania sesban, Balanites aegyptiaca, Albizia coriaria, Ficus sycomorus, Rhus natalensis and Tamarindus indica believed to contain secondary metabolites were screened against ten microorganisms, including the bacteria:- Salmonella typhi ATCC 19430, Escherichia coli ATCC 25922, Bacillus subtilis, taphylococcus aureus ATCC 25923 and Methicillin Resistant Staphylococcus aureus. The fungal strains that were used are; Aspergillus niger, Candida albicans ATCC 90028, Microsporum gypseum, Crytococcus neoformans ATCC 18310 and Trichophyton mentagrophyte. The plants were screened using Kirby Bauer disc diffusion method. Phytochemical screening was carried out to identify the presence or absence of classes of bioactive compounds. Data was analyzed using one way ANOV A, significant means were separated using Tukey's test. Generally, Fuerstia africana, Zanthoxylum chalybeum, Balanites aegyptiaca, Ormocarpum trichocarpum, Senna didymobotrya and Tamarindus indica gave strong antibacterial results of between 14.5 mm and 20 mm as Albizia coriaria, Ficus sycomorus, Commiphora africana Rhus, natalensis Senna didymobotrya, Psidia puntulata, and Tamarindus indica produced strong antifungal results of between 15.5 mm and 20.5 mm. The results ofMICs and the MBCslMFCs of the extracts of Albizia coriaria, Ficus sycomorus, Senna didymobotrya, Psidia puntulata, Fuerstia africana, Balanites aegyptiaca and Tamarindus indica showed a good activity of 0.9375 mg/ml in some test cultures. Salmonella typhi ATCC 19430 and Escherichia coli ATCC 25922 were the least sensitive bacteria while Candida albicans ATCC 90028 was the least sensitive fungus. The present study indicates that the majority of the plantstested are an important source of antibacterial agents especially on Gram positive bacteria(Staphylococcus aureus, Bacillus subtilis and Methicillin Resistant Staphylococcus aureus) and antifungal agents against the dermatophytes especially Microsporum gypseum. This study recommends that the plant extracts with good antimicrobial activitybe subjected to both pharmacological an toxicological studies.
Effect of Soil Amendment With Manure on Nodulation, Biomass and Yield of Soybeans and Climbing Beans in Meru County, Kenya
(Kenyatta University, 2015) Kithira, I. J.
The consequence of intense permanent cultivation of land has been severe loss of soil nutrients through removal of harvested produce, removal of crop residue, leaching and gaseous losses. Experiments were designed to investigate the effect of soil amendment with cow manure, chicken manure and fertilizer on nodulation and nitrogen fixation in climbing beans (MAC 64) and soybeans (Gazelle). Isolation and characterization of isolates together with greenhouse experiments were carried out at Kenyatta University laboratory and greenhouse respectively. Field experiments were carried out at Kaguru Farmers Training Centre and Munithu Girls Secondary School farm. The experimental design was a randomized complete block design with four replications. Each of the legume was planted in soils amended with cow manure, chicken manure, fertilizer and other soils left unamended for control. Data was obtained at 75 % podding and full physiological maturity. Laboratory experiments were carried to isolate and characterize the rhizobia nodulating and fixing nitrogen with climbing beans and soybeans. This was carried out using congo red, litmus milk, Bromothymol blue and peptone agar. Greenhouse experiments were carried out to authenticate the rhizobia obtained from the field. Inocula was prepared from the root nodules of each of the legumes. Isolates from climbing beans inoculated radicles of soybeans and those of soybean inoculated climbing beans. Uninoculated climbing beans and soybeans were used as controls. Cross inoculation was also established in the greenhouse. Rhizobia nodulating and fixing nitrogen with soybeans nodulated and fixed nitrogen with climbing beans. Data obtained from the field experiments was analyzed and significance difference determined in nodule number, root dry weight, stover dry weight, pod number and dry weight of 100 seeds. Results were subjected to standard statistical analysis and presented using both descriptive and quantitative statistical procedures. The effect between amendments was determined using Genstat software for the analysis of variance (ANOVA) and mean separated using least significance tests at 5% level. Indigenous bradyrhizobia do not nodulate effectively in soybean and climbing beans in soils with low levels of nitrogen. Nodules did not form in beans planted in the soils amended with nitrogen fertilizer. Cross inoculation of rhizobia was observed between soybean and climbing beans in the greenhouse. Chicken manure, cow manure and nitrogen fertilizer application had effect on nodulation, root dry weight, stover dry weight, pod number and dry weight of 100 seeds on both soybeans and climbing beans. Climbing beans at Munithu Girls secondary School farm showed better performance in soils amended with chicken manure in the parameters assessed. BNF should be exploited with the view of decreasing overdependence on nitrogen fertilizer for sustainable agriculture. There is need for continuous screening of large numbers of native bradyrhizobia to understand their specificity in nodulation and nitrogen fixation
Management of crown gall disease of roses using agrobacterium radiobacter, corn oil and copper hydroxide and oxychloride in Kenya
(2015) Murugi, Gitari Judith
The cut-flower industry is one of the fastest growing sub-sectors of the horticultural industry contributing significantly to the continued growth of Kenyan economy. Roses are the most popular cut-flowers world-wide. Rose flower production in Kenya faces significant challenges particularly with regard to pests and diseases. Crown gall disease caused by A. tumefaciens is one of the limiting factors in the production of roses. The disease is widespread in rose flower farms and nurseries in Kenya causing a substantial loss of yield and therefore there is an urgent need to manage it. The study aimed at evaluating the antagonistic activity of naturally occurring A. radiobacter isolates from different flower farms in four ecological regions notably Nanyuki, Naivasha, Murang‟a and Timau against A. tumefaciens. In addition, Elianto oil, copper hydroxide (kocide 2000) and copper oxychloride were evaluated as chemical control agents Field survey was conducted over the period between August, 2012 and October, 2012. Gall and soil samples were collected during the period between November, 2012 and December, 2012. Laboratory work was conducted at Kenyatta University, Microbiology Department Laboratory while greenhouse experiments were carried out at Branan farm (Muranga County). The gall and soil samples were isolated on Yeast Extract Mannitol Agar supplemented with Congo red and Yeast Extract Peptone media. Colony morphology and standard biochemical tests including: Gram staining, catalase test, urease test, salt tolerance test, 3-ketolactose test, motility test and H2S production were performed for identification and confirmation of the isolates based on their Gram staining and cultural characteristics. Kirby-Bauer disc diffusion technique was used to determine antimicrobial sensitivity patterns of bacteria to antibiotics. Carrot disc assay test was conducted on A. tumefaciens for pathogenicity test while in vitro antagonistic test was done on A. radiobacter. In the greenhouse experiments, pathogenecity test was carried out using A. radiobacter and A. tumefaciens isolates on four varieties of rose plants. Minimum incidence (6%) of crown gall was observed on Topsun, Fuschiana and H3O rose varieties when A. radiobacter isolates were applied compared to 54% in the control. In Furiosa variety, there was minimal incidence of crown gall disease on treated plants and in control. There was no significant differences (P>0.05) in the interaction between rose flower variety and treatments on the number of plants with galls. In chemical control, there was no significant difference (P>0.05) in the interaction between treatment and variety with regard to number of plants with galls. The study confirmed that A. radiobacter had the potential in the management of crown gall disease on rose flower plants. Therefore, the study recommends the use of A. radiobacter (biological control agent) and chemical control methods to minimize spread of the disease.
Determination of Bacterial Composition, Heavy Metal Contamination and Physico-Chemical Parameters of Fish Pond Water in Abothuguchi Central, Meru County, Kenya
(Kenyatta University, 2015) Laibu, P. K.
Fish farming has been practised all over the world for centuries. Throughout history, humans have used fish as a supplementary source of proteins and as a source of income. Fish performs all their body functions in water and therefore the quality of water is very important to their livelihood. Farmers have suffered losses due to the death and stunted growth of fish as a result of bacterial infections and diseases among other causes. The presence of these bacteria in fish pond water and their pathogenic effects varies with the quality of the pond water together with the variation in the frequency with which water is changed in the ponds. Physico-chemical parameters of pond water and heavy metals affect growth and productivity of fish. This research aimed at determining the contamination levels of both faecal and pathogenic bacteria namely Salmonella spp., faecal Streptococcus, faecal coliforms Pseudomonas spp.,Vibrio cholerae and E. coli in fish ponds water, levels of heavy metal contamination and variability of physico-chemical parameters and their effects on fish. Isolation of faecal indicators and pathogens was carried out using standard laboratory methods. Some physico-chemical parameters were measured in situ using a portable Universal multiline P4 WTW (Wilheim Germany) meter while others were analysed in the laboratory. The determination of heavy metal presence and concentration in the water samples was carried out by the use of Flame Atomic Absorption Spectrometer (FAAS). The results indicated that the pond water was highly contaminated with faecal streptococci and faecal coliforms and they varied significantly in the sites at p=0.0001. Pearson correlation analysis showed positive correlation between prevalence of faecal streptococci and faecal coliforms (r=0.732 at P< 0.01). Potential pathogens namely Vibrio spp., Salmonella spp., P. aeruginosa and E.coli were isolated from the water samples with high population. Physico-chemical parameters namel pH and dissolved oxygen deviated from the permissible limits. The study has indicated that the fish ponds water was highly contaminated with both faecal and pathogenic bacteria with physico-chemical parameters varying significantly at p=0.0001. Heavy metals with the exception of iron were within the recommended limits hence no significant contamination of the fish pond water. The study recommends use of treated tap water, regular monitoring of fish pond water and sensitization of farmers on bacterial contamination of pond water. Further studies with the aid of molecular techniques should be used to characterize the bacteria. The finding of this study can, therefore, serve as an impetus to improve fish farming in Meru County, as a way of meeting the growing nutritional demands in the country.
In vitro response of phomopsis theae to the products of azadirachta indica and extracts of warburgia ugandensis
(2015) Chepkorir, Soy Linner
Tea is one of the major cash crops in Kenya and a means of livelihood to people living around the region where it is grown. Branch and collar canker disease is among the many diseases which affect the crop hence reducing its production. Methods used to control the disease mainly involve the use of chemical fungicides which are toxic and not environmentally friendly. This study was therefore done to determine the use of plant products and extracts to manage the disease. Among the products used were Nimbecidine and Trilogy which are products of neem tree. The Warburgia ugandensis extracts from the bark, root and leaf were also used in vitro to determine the inhibition of Phomopsis theae the causative agent of Branch and Collar Canker. These were compared with the inhibition of standard fungicides (Topsin and Saaf). Nimbecidine and Trilogy were also tested at the concentration of 10 ppm, 25 ppm, 50 ppm and 100 ppm, while W. ugandensis extracts were tested at the rates of 10 g/100 ml, 15 g/100 ml and 20 g/100 ml. Nimbecidine inhibited growth more than Trilogy in all the concentrations and were not significantly different from those of Topsin and Saaf. Stem bark extracts of W. ugandensis were also effective in inhibiting the growth of P. theae with inhibition of 97.64 per cent in all the rates. Root was next in inhibition with 78.8, 19.45 and 9.89 per cent in 20 g, 15 g and 10 g respectively. The leaf extracts did not inhibit growth at any rate. In liquid media, similar results were observed. In Nimbecidine, mycelial weights were significantly lower compared to Trilogy. Stem bark extracts also had lower mycelial weights, followed by the root and then leaf among the extracts. Nimbecidine and bark extracts of W. ugandensis were compared with standard fungicides, Topsin and Saaf, and the extract was comparable to the fungicides both in solid and liquid media. They were able to inhibit the growth of P. theae
Post-Harvest Fungi Diversity and Level of Aflatoxin Contamination in Stored Maize: Cases of Kitui, Nakuru and Trans-Nzoia Counties in Kenya.
(Kenyatta University, 2015) Gachara, Grace W.
Aflatoxin contamination of maize in Africa poses a major threat to food security and the health of many African people. In Kenya, aflatoxin contamination of maize is high due to the environmental, agricultural and socio-economic factors. Many studies have been conducted to understand the scope of the problem especially at pre-harvest level, but few of them have been concentrated to the post-harvest level. This research was carried out to gather scientific information on the fungi population, genetic diversity and aflatoxin levels during post-harvest period. The study was conducted in three geographical locations of; Kitui, Trans-Nzoia and Nakuru Counties. Samples were collected from storage structures of farmers and transported to the Biosciences eastern and central Africa (BecA), International Livestock and Research Institute (ILRI) hub laboratories. Mycoflora were recovered using the direct plating method. A total of five fungal genera (Aspergillus, Penicillium, Fusarium, Rhizopus and Bsyochlamys spp.) were isolated from the stored maize samples. The most common fungal species that were isolated from the three study sites included A. flavus at 82.03 % followed by A. niger and F. solani at 49 % and 26 % respectively. The aflatoxin producing fungi A. flavus was recovered in 82.03 % of the samples. Aflatoxin levels were analysed on both the maize samples and in vitro. Most of the A. flavus isolates recorded a high level of aflatoxin when they were analysed for presence of aflatoxin B1 using ELISA. In Kitui, all the samples had aflatoxin levels above 10 ppb with a total aflatoxin mean of 219.2 ppb. In Trans-Nzoia, only 3 samples (n=39) had their aflatoxin levels less than 10 ppb while in Nakuru, the total aflatoxin mean level of this region was 239.7 ppb. When individual samples were analysed using Vicam fluorometer method, aflatoxin analysis revealed that most of the samples (58.4 %) had been contaminated. The means were significantly different (p≤0.05) in all the three locations. Genetic relationships of A. flavus isolates were determined using 13 Simple Sequence Repeats (SSRs) markers. The results were used to generate a phylogenetic tree using DARwin5 software program. A total of 5 distinct clusters were revealed among the genotypes. The isolates appeared to cluster separately according to the geographical locations. Principal Coordinates Analysis (PCoA) of the genetic distances among the 91 A. flavus isolates explained over 50.3 % of the total variation when two coordinates were used to cluster the isolates. Analysis of Molecular Variance (AMOVA) showed high variation of 87 % within populations and 13 % among populations. This research has shown that A. flavus is the main fungal species infecting maize grains in the three sampled sites in Kenya. The effects of aflatoxins on human populations in Kenya demonstrates a clear need for tools to manage contamination of locally produced maize. Food basket surveys for aflatoxin contamination should be conducted on a regular basis. This would assist in obtaining reliable data on aflatoxin incidence in different food crops. This would go a long way in defining the most appropriate and long-lasting control strategies for this menace that would suffice to the entire Kenyan population.
Prevalence and Susceptibility Profiles of Bacterial Pathogens Associated with Urinary Tract Infections in Children Presenting at Kisii Level 5 Hospital, Kisii County, Kenya
(Kenyatta University, 2015) Nyambane, Ontita Clive
Urinary Tract infection (UTI) is a serious infection causing illness in infants and children. It represents one of the most common diseases encountered in medical practice today. Despite the widespread availability of antibiotics, it remains the most common bacterial infection. Antimicrobial susceptibility testing therefore provides information that allows physicians to select the most appropriate antimicrobial agents for treating these infections and give the most effective antibiotic. This cross-sectional study was conducted to determine the prevalence of UTI among children presenting at Kisii Level 5 hospital and to evaluate the sensitivity patterns of the identified isolates to commonly used antibiotics. A total of 186 urine samples were collected from in and out-patients attending Kisii level 5 Hospital, Kisii County, Kenya between December 2012 and March 2013. Urine samples accompanied by microbiology request forms were delivered directly to the laboratory. All sample processing and patient’s biodata were carried out centrally in Kisii level 5 hospital microbiology laboratory. The samples were cultured on Cystein lactose electrolytedeficient (CLED) media and incubated for 18 hours at 37oC. Criteria for defining significant bacteriuria was the presence of 105colony forming units per millimetre of urine. The bacterial isolates recovered were tested against Ampicilin, Tetracycline, Nitrofurantion, Nalidixic acid, Streptomycin, Co-Trimoxazole and Gentamicin using Kirby Bauer disc diffusion technique.Data was presented as frequencies. Chi square analysis (2)was used in comparing of positive UTI cases according to individual characteristics. Evaluations were carried out at 95 % confidence level and P< 0.05 was considered statistically significant. Among the 186 samples examined 63.4 % of them were from female patients and 36.6 % from male patients; 26 (14 %) samples had positive bacteriuria with Escherichia coli isolates being the highest with 13 (50 %,),Klebsiella 8 (30.8 %), Staphylococcus aureus 4 (15.4 %) and Pseudomonas aureginosa1 (3.8 %). The isolates were sensitive to Nitrofurantion, Nalidixic acid, and Streptomycin while resistant to Ampicilin, Tetracycline, Gentamicin and Cotrimoxazole. There is therefore need to monitor the profile of etiological bacterial agents of UTI and the antimicrobial resistance regularly to keep track of effectiveness of serving therapeutic agents.
Prevalence and antimicrobial susceptibility profiles of bacterial pathogens isolated from outpatients with Upper respiratory tract infections in Kitui District Hospital, Kenya
(Kenyatta University, 2015) Mutinda, Josphat
Respiratory tract infections, such as pharyngitis, laryngitis, common cold, sinusitis and tonsillitis are the most frequently occurring infections of all human diseases. Since these infections often seem minor, they are more commonly discounted as temporary inconveniences that cause transient discomfort. However, limited information has been documented in Kenya in relation to occurence and prevalence of the etiological agents causing upper respiratory tract infections. Therefore, this study was aimed at determining the prevalence of bacterial agents causing upper respiratory tract infections and their susceptibility patterns to commonly used antibiotics among outpatients in Kitui district hospital. The objectives of this study were; To determine the prevalence of upper respiratory tract infections in patients 'of different age groups and sexes, to isolate, identify and assess the distribution of bacterial pathogens associated with upper respiratory tract infections, to determine the prevalence of pathogenic bacteria of the upper respiratory in different age groups and sexes and to determine antimicrobial susceptibility profiles of the isolated bacterial pathogens. A total of 237 throat swabs were collected during the period between November, 2012 to April, 2013 and innoculated onto Blood agar, MacCkonkey agar and Chocolate agar then incubated at 37°C for 24 hours. Colony morphology and standard biochemical tests; Gram staining, catalase test, coagulase test, Mannitol fermentation test, bacitracin sensitivity test, bile solubility, hippurates test, optochin sensitivity test and germ tube test were performed for identification and confirmation of the isolates based on their Gram staining and cultural characteristics. Kirby-Bauer disc diffusion technique was used to determine antimicrobial sensitivity patterns of the bacteria to antibiotics. P values of::; 0.05 were consindered to have clinical and epidemiological significance. The sample consisted of 36.7 % males and 63.3 % females. The age between I and 5 years was a risk factor for these infections with clinical and epidemiological significance. Bacteria isolated were S. aureus (44.3 %), viridans group streptococci (32.5 %), S. pyogenes (13.5 %) and 5 % were mixed cultures involving C. albicans and either viridans group streptococci or S. aureus. Resistance of bacterial pathogens to at least one antibiotic in Kitui district hospital was; viridans group streptococci (48.2 %), S. aureus (40.5 %), S.pyogenes (28.1 %) and there were no cases of multi-drug resistance. S. aureus was the most prevalent isolate. Proper interventions should therefore be put in place to prevent young people from contracting and transmitting upper respiratory tract infections.
Efficacy of some medicinal plants used in various parts of Kenya in treating selected bacterial and fungal pathogens
(Kenyatta University, 2015-01) Jacqueline, India
Medicinal plants have been used since time immemorial to treat and prevent human ailments. WHO indicates that up to 80% of the world’s population uses traditional medicine. Infections caused by bacteria and fungi have become a major health problem globally accounting for over 50,000 deaths every day. It is estimated that more than 70% of the pathogenic bacteria are resistant to at least one of the antibiotics commonly used to treat them. Conventional drugs are expensive and have side effects. Many plants have been used by various communities in Kenya in the treatment of bacterial and fungal infections but they have not been validated. The main aim of this study was to determine the efficacy of some medicinal plants used by various communities in Kenya that treat the selected bacterial and the selected fungal diseases in man. An ethnobotanical survey was used to select and collect plants from Mwingi North, Kisii South and Rarieda Districts based on their use to treat infectious diseases such as skin infection, diarrhea and many others. Crude extracts from Zanthoxylum chalybeum, Boscia angustifolia, Melia volkensii, Zanthoxylum gilletii, Fuerstia africana, Urtica dioica, Vernonia amygdalina, Ricinus communis, Commiphora africana, Psidia puntulata, Senna didymobotrya, Ormocarpum trichocarpum, Sesbania sesban, Balanites aegyptiaca, Albizia coriaria, Ficus sycomorus, Rhus natalensis and Tamarindus indica believed to contain secondary metabolites were screened against ten microorganisms, including the bacteria:- Salmonella typhi ATCC 19430, Escherichia coli ATCC 25922, Bacillus subtilis, Staphylococcus aureus ATCC 25923 and Methicillin Resistant Staphylococcus aureus. The fungal strains that were used are; Aspergillus niger, Candida albicans ATCC 90028, Microsporum gypseum, Crytococcus neoformans ATCC 18310 and Trichophyton mentagrophyte. The plants were screened using Kirby Bauer disc diffusion method. Phytochemical screening was carried out to identify the presence or absence of classes of bioactive compounds. Data was analyzed using one way ANOVA, significant means were separated using Tukey’s test. Generally, Fuerstia africana, Zanthoxylum chalybeum, Balanites aegyptiaca, Ormocarpum trichocarpum, Senna didymobotrya and Tamarindus indica gave strong antibacterial results of between 14.5 mm and 20 mm as Albizia coriaria, Ficus sycomorus, Commiphora africana Rhus, natalensis Senna didymobotrya, Psidia puntulata, and Tamarindus indica produced strong antifungal results of between 15.5 mm and 20.5 mm. The results of MICs and the MBCs/MFCs of the extracts of Albizia coriaria, Ficus sycomorus, Senna didymobotrya, Psidia puntulata, Fuerstia africana, Balanites aegyptiaca and Tamarindus indica showed a good activity of 0.9375 mg/ml in some test cultures. Salmonella typhi ATCC 19430 and Escherichia coli ATCC 25922 were the least sensitive bacteria while Candida albicans ATCC 90028 was the least sensitive fungus. The present study indicates that the majority of the plants tested are an important source of antibacterial agents especially on Gram positive bacteria (Staphylococcus aureus, Bacillus subtilis and Methicillin Resistant Staphylococcus aureus) and antifungal agents against the dermatophytes especially Microsporum gypseum. This study recommends that the plant extracts with good antimicrobial activity be subjected to both pharmacological and toxicological studies.
Culturing, Characterization and Identification of Candidate Microorganisms in Cattle Ear, Responsible for Producing Volatile Constituents Attractive to the Brown Ear Tick
(Kenyatta University, 2015-09) Kogo, Kipchumba Kenneth
East Coast Fever is a disease of cattle which results in high animal mortality with corresponding economic losses to farmers and to the nation. The disease is caused by a protozoan agent whose vector is Rhipicephalus appendiculatus (Brown Ear Tick). The tick feeds dominantly inside the cattle ear. Studies have shown that the adults of R. appendiculatus exhibit „pull-push‟ effect that guides them to their preferred feeding site. This is linked to the presence of ear volatiles which attracts and anal volatiles which repels the tick. However, there is limited information that describes what produces the volatiles within the cattle ear. This study aims at establishing the role of ear microbes to the brown ear tick behavior while locating its preferred feeding site. In a preliminary observation, release of the ticks on the cattle with one ear sprayed with a broad-spectrum antibiotic showed that most ticks were attracted to the untreated ear, suggesting that the attractant volatiles are derived from specific microbial populations. In the present study where twelve cattle were used, one ear in each cow was treated with vetmycin a broad-spectrum antibiotic while the other ear was left untreated and the orientation behavior of the ticks (R. appendiculatus) placed at six different parts of cattle monitored. Most of the ticks moved to the untreated cattle ear (P<0.001,t-test). Ear swabs were collected and cultured in a general media to obtain a culture of the microbes for in-vitro behavioral tick experiments and genomic studies. In a choice laboratory experiment, ticks were also observed to orient towards cultivable cattle ear microbes relative to a negative control (P< 0.001,t-test). General lab media (Nutrient Agar) was then used to culture different micro-organisms. Sensitivity tests carried out to determine the efficacy of the antibiotic spray used on the cattle ears showed that most microbes were sensitive to the antibiotics contained in the spray according to Kirby Buer calibrations. Profiles of aerobically cultivable microbial communities in each of the twelve cows were investigated using pyrosequencing based analysis. Genomic DNA was extracted and amplified using two sets of primers U1F, U1R which targets band lengths of 490bp and 500bp and primers 27F, 1492R which targets bands lengths of 1490bp. Gene sequences of each ear helped to identify the specific genus of each microorganism and profiles of the candidate microorganisms. Pyro-sequencing blast results revealed that there were diverse communities of microbes majority of which were bacteria. The study lays down significant groundwork in identifying the specific ear microbes responsible for the production of the constituents of ear blend that is responsible for attracting the adults of the Brown Ear Tick. This may open up novel ways of manipulating the production of the blend and in controlling the tick
Assessment of total and mobile heavy metals in amended compost of water hyacinth obtained from Lake Victoria, Kisumu County
(Kenyatta University, 2015-11) Towett, Kiprono Gideon
Water hyacinth (Eichhornia Crassipes) invasion in Lake Victoria has become a matter of concern over the last two decades. There has been suggestion on the possibility of producing compost from water hyacinth as a way of managing the weed cover in the lake and at the same time help local farmers in the region boost their agricultural production by supplementing the use of commercial chemical fertilizers. However, the safety of using water hyacinth’s compost has to be investigated as studies have shown that water hyacinth accumulates heavy metals from the environment. The specific objectives of the study were to determine the total concentrations of heavy metals (Pb, Cd, Ni and Cu) in water hyacinth compost, to determine the effect of the carbonaceous materials (cattle manure and molasses), and effective microorganisms treatment of water hyacinth’s compost feedstock materials on the mobile concentrations of heavy metals and to determine the relationship between total and mobile concentrations of heavy metals in compost. In the study, water hyacinth compost was prepared using commercial effective microorganisms (EM) solution and carbonaceous materials (cattle manure and molasses) separately as starter cultures for composting. Compost samples were digested with concentrated nitric acid to extract total metals and mobile concentrations were extracted using de-ionized water. Concentration of heavy metals in the compost was determined using Atomic Absorption Spectroscopy and the data collected was analyzed for significant differences (p < 0.05) using one-way Analysis of Variance (ANOVA) with Statistical Analysis System (SAS) Version 9.2 software. Means were separated using Tukey`s test at 5 % level. Pearson correlation analysis was also carried out to check the significances of the linear relations between total and mobile concentrations. Assessment of heat released during composting of water hyacinth showed that water hyacinth compost attained stability and thus maturity after 60 days of composting. The range of total heavy metals in compost samples were 1.23-1.46 mg/kg (copper), 0.32-0.35 mg/kg (cadmium), 0.25-0.32 mg/kg (nickel), 0.95-1.41 mg/kg (lead). The mean concentrations of the mobile heavy metals in mg/kg for the control, EM, manure and molasses treatments were copper: 0.054, 0.055, 0.027 and 0.049. Cadmium: 0.023, 0.032, 0.018, and 0.035. Nickel: 0.036, 0.027, 0.033, and 0.031. Lead: 0.043, 0.061, 0.023 and 0.093. There were significant differences in the mean concentrations of total and mobile concentrations of heavy metals between treatments. The total concentrations of heavy metals in water hyacinth compost, irrespective of treatments, were within acceptable limits and the addition of carbonaceous materials significantly affected the mobility of heavy metals. Nickel had an all positive relationship between total and mobile concentrations. However, for Cu, Cd and Pb an increase in total concentrations did not necessarily correspond to an increase in mobile concentrations. The mobile concentrations of heavy metals in compost were not predictable from their total content. Manure treatment had the least fraction of mobile heavy metals. It is therefore recommended that the composting of water hyacinth for organic fertilizer and as a way of disposing harvested water hyacinth biomass be done. The study also recommends amending of water hyacinth compost feedstock with cattle manure in order to reduce mobility of heavy metals in compost and consequently help alleviate possible adverse effects of compost on the environment.
Prevalence, susceptibility patterns and risk factors associated with staphylococcus aureus presence in marketed milk and milk products within Nairobi City County, Kenya
(Kenyatta University, 2016-04) Macharia, John Macharia; Cheruiyot, Richard; Nyerere, Kimang`a A.
Staphylococcus aureus is a major food-borne pathogen that poses a serious threat to public health. In Kenya, with the continuous water shortage, proper sanitary conditions are not sufficiently met and hence pre-disposing the community to S. aureus infections. One of the difficulties of controlling S. aureus food poisoning is that food can contain a very high population of the bacteria without being noticeably identified. It has been suggested that food-borne diseases represent one of the most widespread and overwhelming public health problems in poor resource settings. The increasing rate of multidrug resistant S. aureus has continued to pose a challenge to the pharmaceutical firms and patients management. The aim of this study was therefore to determine the presence of S. aureus in milk and milk products, antimicrobial susceptibility patterns and factors associated with food contamination. A total of 334 samples were collected for analysis in the laboratories. A loop-full of each sample was streaked directly on MacConkey agar and Blood agar. Suspected isolates were subcultured in Mannitol salt agar which was used as an indicator media. Sensitivity test was accomplished using Muller-Hinton agar. Biochemical tests; Catalase test and Coagulase test were used as confirmatory tests for S. aureus. To determine antimicrobial susceptibility, panels of selected antibiotics commonly used in empirical treatment of S aureus infections were obtained from different classes. The antibiotics were Penicillin G, Erythromycin, Vancomycin, Chloramphenicol, Tetracycline, Gentamycin, Methicillin and Ciprofloxacin. From all the 54 samples of raw milk analyzed, 35 (64.81%) samples were contaminated by S aureus. In pasteurized milk, out of 112 samples, 23 (20.54%) samples were contaminated while in yoghurt, out of 112 samples, 12 (10.71%) samples were contaminated. In ice cream, out of 56 samples, 2 (3.57%) were contaminated. All isolates were found to be 100 % sensitive to Tetracycline, Ciprofloxacin, Erythromycin and Methicillin. Resistance to Penicillin G was occasionally observed across the different sources of milk and milk products. From the milk outlets selling raw milk within the study area, regular opening of the containers to sell milk pre-disposed the milk to hand contamination and consequently greater risks of contamination by environmental contaminants. Out of 120 respondents interviewed, an average of 84 (70%) claimed to be aware of the health risks associated with milk. Of the respondents, 28 (23%) claimed to be aware of diseases associated with consumption of contaminated milk. Most of them claimed to have encountered stomach disorders and diarrhea while others claimed to have experienced body rashes, severe headache and vomiting. On average, 8 (9%) of the respondents claimed to have contracted a disease as a result of drinking contaminated milk within the last one year. It was established that 118 (98%) of food handlers did not receive any formal training regarding food hygiene. Information generated from the study provides a basis upon which formulation of better policies regarding raw milk and milk products can be based on. In addition, given the imminent risks of infection and resistance involved, the relevant authorities should adopt severe inspection measures in order to regulate or prohibit the informal sale of milk.

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