Factors associated with bacterial contamination of shallow well water sources. Case Study of Juja hostels Kiambu County

The use of water from polluted water sources poses numerous public health challenges in developing countries. The ultimate purpose of any solid and liquid waste management plan is to mitigate environmental pollution; these goals become unachievable in the absence of a participatory approach to integrated waste management. This study sought to determine the extent of underground pollution of groundwater sources in Juja Town. Sanitary inspection and water quality analysis are complementary and valuable tools for characterizing and protecting water safety. The quality of the shallow wells is of great importance because it is used for consumption in Juja hostels. A two-stage cluster sampling strategy was adopted to obtain a representative sample size. Data collection involved the administration of questionnaires and field observation checklists, and E. coli levels present in the water were determined by the number of positive tubes in the table of computation of most probable number (MPN). Results showed that the predominant types of waste disposal practices observed in Juja were septic tank systems (77%) for liquid waste and private collection (87.3%) for solid waste methods. Sixty-eight per cent of the water samples were found to be positive (they exceeded the WHO (2004) maximum permissible load of 0.01/100 ml for drinking water. Three sanitary risk factors had a statistically significant effect on the dependent variable: the distance of the septic tank from the well on the level of water contamination (0.016), the liquid waste management plan (0.039), and the fitness of the water well cover on the level of water contamination (0.024). Shallow well water sources are unsuitable for use in food processing and drinking due to the presence of E. coli bacteria. The consequences of consuming contaminated water can be expensive to treat. Water from wells in Juja is contaminated with E. coli levels ranging from <3 - >1000 MPN/g, indicating fecal contamination in the area's underground water sources

Potential use of rhizobial bacteria as promoters of plant growth for increased yield in landraces of African cereal crops

Rhizobia form root nodules that fix nitrogen (N2) in symbiotic legumes. Extending the ability of these bacteria to fix N2 in non-legumes such as cereals would be a useful technology for increased crop yields among resource-poor farmers. Although some inoculation attempts have resulted in nodule formation in cereal plants, there was no evidence of N2 fixation. However, because rhizobia naturally produce molecules (auxins, cytokinins, abscicic acids, lumichrome, rhiboflavin, lipo-chito-oligosaccharides and vitamins) that promote plant growth, their colonization and infection of cereal roots would be expected to increase plant development, and grain yield. We have used light, scanning, and transmission electron microscopy to show that roots of sorghum and millet landraces from Africa were easily infected by rhizobial isolates from five unrelated legume genera. With sorghum, in particular, plant growth and phosphorus (P) uptake were significantly increased by rhizobial inoculation, suggesting that field selection of suitable rhizobia/cereal combinations could increase yields and produce fodder for livestock production

Diagnosis of Bacterial Vaginosis and evaluation of associated factors: Comparable findings using Hay/ Ison’s and Nugent’s Scoring System

Although Nugent’s criterion is considered as the gold standard for the diagnosis of bacterial vaginosis (BV), the method requires an experienced slide reader and considerable time and skill. We compared Hay/ Ison and Amsel with Nugent’s scoring criteria to determine the prevalence and corelates for BV among women of reproductive age attending reproductive health related clinics (family planning, post-natal and sexually transmitted Infection - STI) at Mbagathi County Referral Hospital in Nairobi. Vaginal specimens were collected from 201 consenting women, presenting with or without the vaginal symptoms of vaginitis. BV was diagnosed using Hay/ Ison, Amsel and Nugent’s method while factors corelates were gathered using structured interviews. Sensitivity, specificity, and predictive values for positive and negative test were calculated for both Hay/ Ison and Amsel methods using Nugent criteria as the gold standard. Corelates for BV in this population were evaluated against the three methods. There were 66 cases (32.8%) of BV by Amsel’s method, 79 cases (39.3%) of BV by Hay/ Ison’s Criteria and 72 (35.8%) cases by the Nugent’s method. Using Nugent criteria as the gold standard, the concordant, sensitivity, specificity, positive and negative predictive values of tests were. Amsel: 77.1%, 63.9%, 84.5%, 80.7% and 69.7% respectively, and Hay/ Ison: 96.5%, 100%, 94.6%, 100% and 91.1% respectively. Evaluating the performance of Hay/ Ison test against Amsel criteria, the standard method for clinical diagnosis; offered no improvement in sensitivity 72.7%, specificity 77.1%, NPV 85.3% and PPV 60.8% when compared to Nugent’s score. Factors independently associated with BV infection included. For all the three tests: Presence of clue cells; Nugent and Hay/ Ison methods: education level, marital status and positive for whiff tests: For Nugent and Amsel criteria: Presence of vaginal discharge and for Hay/ Ison test: condom use. Attributes of socio-demographic and sexual hygiene and behavior contributes to high prevalence of BV among women in the capital city of Kenya. The Hay/ Ison’s method shows good agreement with the Nugent criteria and can be recommended as a stand-alone alternative assay to Nugent’s criteria or as a confirmatory test for BV in this population. Key words: Nugent, Amsel and Hay/ Ison method Bacterial Vaginosis, Test performance, Correlates, Women of Reproductive Age, Western Kenya

Potential use of rhizobial bacteria as promoters of plant growth for increased yield in landraces of African cereal crops

Rhizobia form root nodules that fix nitrogen (N2) in symbiotic legumes. Extending the ability of these bacteria to fix N2 in non-legumes such as cereals would be a useful technology for increased crop yields among resource-poor farmers. Although some inoculation attempts have resulted in nodule formation in cereal plants, there was no evidence of N2 fixation. However, because rhizobia naturally produce molecules (auxins, cytokinins, abscicic acids, lumichrome, rhiboflavin, lipo-chito-oligosaccharides and vitamins) that promote plant growth, their colonization and infection of cereal roots would be expected to increase plant development, and grain yield. We have used light, scanning, and transmission electron microscopy to show that roots of sorghum and millet landraces from Africa were easily infected by rhizobial isolates from five unrelated legume genera. With sorghum, in particular, plant growth and phosphorus (P) uptake were significantly increased by rhizobial inoculation, suggesting that field selection of suitable rhizobia/cereal combinations could increase yields and produce fodder for livestock production. Key Words: Rhizobia, N2 fixation, plant growth, sorghum, millet African Journal of Biotechnology Vol.3(1) 2004: 1-

Genotypes of Candida albicans from Stool Samples of HIV Sero Positive and HIV Negative Individuals in Nairobi, Kenya

Candida albicans is one of the commonest opportunistic yeast pathogens that infect both healthy and immune-compromised individuals. Currently there are five recognized genotypes of C. albicans based on the 25 rDNA gene. Different genotypes of C. albicans have been shown to differ in their virulence and susceptibility to antifungal drugs and, thus accurate identification of the infecting genotype is essential for guiding antifungal therapy. The aim of the study was to determine the genotypes of C. albicans from stool samples of HIV sero positive and HIV negative individuals and ascertain whether there is an association between HIV status and genotype distribution. A total of forty four (44) Candida albicans isolates from the stool samples of 28 HIV sero positive patients attending an outpatient HIV/AIDS management clinic and 16 HIV negative individuals attending a hospitality industry support program at Kenya Medical Research Institute (KEMRI) were genotyped using PCR primer pairs that span the transposable intron region of the 25S rDNA. Genotype A C. albicans was the most prevalent type (61.4%) followed by genotype C (11.4%) and genotype B (4.5%). Genotype B C. albicans was not isolated from HIV negative individuals. There was no significant difference in the genotype distribution of C. albicans isolates from HIV sero positive and HIV negative individuals (p=0.304). Ten (22.7%) C. albicans isolates could not be genotyped using the transposable region primers an indication of possible new genotypes. Genotype A is the most predominant C. albicans isolate both in HIV sero positive and HIV negative individuals and there is no predilation of any genotype to HIV infected. There is a possibility of new genotypes of C. albicans and sequence analysis may be warranted. Keywords: Genotypes, C. albicans, stool, HIV, Kenya

Cultural Characterization of Fungi Isolated From Oil Contaminated Soils

Application of Fungi for effective removal of hydrocarbon contamination from soil is being considered as the better option when it comes to biodegradation. Other method like physical and chemical bioremediation leads to production of toxic compounds and these methods are not cost effective. In the present study, soil samples from four different oil contaminated soils were assessed for any recovery of fungi present. Cultural characterization was used as preliminary identification using keys.  Initial isolation from the oil contaminated soil was done using potato dextrose agar.  Colonies were observed and characterized morphologically. The isolates were grown at varied temperatures and pH. Eight fungal isolates were recovered from polluted soils namely, Trichoderma viride, Trichoderma spirale, Neosartorya pseudofischeri, Neosartorya aureola, Aspergillus flavus, Aspergillus terreus, Penicillium griseofulvum and Trichoderma longibrachiatum.  The optimum growth temperature range for the eight fungi was 30oC and 40oC.  There was no growth at 50oC for all isolates except some slight growth by Aspergillus flavus.  Optimum growth at pH 7 and pH 9 and poor growth at pH 5 was noted. This study will contribute to the database on locally available fungal diversity and their ecology. Keywords.  Fungi, Bioremediation, oil contamination, biodegradatio

Potential of indigenous bradyrhizobia versus commercial inoculants to improve cowpea ( Vigna unguiculata L. walp.) and green gram ( Vigna radiata L. wilczek.) yields in Kenya

Limited information is available on reduced cowpea (Vigna unguiculata L. Walp.) and green gram (Vigna radiata L.Wilczek.) yields in Kenya. Declining soil fertility and absence or presence of ineffective indigenous rhizobia in soils are assumptions that have been formulated but still require to be demonstrated. In this study, soils were collected from legume growing areas of Western (Bungoma), Nyanza (Bondo), Eastern (Isiolo), Central (Meru) and Coast (Kilifi) provinces in Kenya to assess indigenous rhizobia in soils nodulating cowpea and green gram under greenhouse conditions. Our results showed that highest nodule fresh weights of 4.63 and 3.32 g plant_1 for cowpea and green gram were observed in one soil from Isiolo and another from Kilifi, respectively, suggesting the presence of significant infective indigenous strains in both soils. On the other hand, the lowest nodule fresh weights of 2.17 and 0.72 g plant_1 were observed in one soil from Bungoma for cowpea and green gram, respectively. Symbiotic nitrogen (N) fixation by cowpea and green gram was highest in Kilifi soil with values of 98% and 97%, respectively. A second greenhouse experiment was undertaken to evaluate the performance of commercial rhizobial inoculants with both legumes in Chonyi soil (also from Coast province) containing significant indigenous rhizobia [>13.5_103 Colony Forming Units (CFU) g_1]. Rhizobial inoculation did not significantly (P < 0.05) affect nodulation, biomass yield and shoot N content in cowpea and green gram compared with controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the 16S-23S rDNA intergenic spacer (IGS) region analysis of nodules revealed six groups of which only IGS Group IV corresponded with those from commercial inoculants applied, indicating a lower competitiveness of inoculated strains. In cowpea, IGS III was dominant in nodules of plants inoculated with Biofix and Rizoliq commercial inoculants, and the uninoculated control treatment (63.2, 60 and 52.9%, respectively). Similarly, in green gram, IGS Group III was dominant in nodules of plants inoculated with Biofix 704 and Rizoliq commercial inoculants, and the uninoculated control treatment (75, 73.7 and 61.1%, respectively). Our results suggest that the systematic inoculation of both legumes with current available commercial inoculants to improve biomass yields is not necessary in these regions of Kenya. Also, according to our study, it would make sense to promote the utilization of indigenous strains performing well with both legumes. (Résumé d'auteur