Browsing by Author "Kiruki, Silas"

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Analysis of Microbial Quality of Drinking Water in Njoro Sub-county, Kenya
(2019-10) Kirianki, Philip; Othira, J.O.; Kiruki, Silas;
Drinking water should be free of microbial pathogens so as to be regarded as potable water and safe for drinking. However, water is prone to fecal contaminants which are the sources of gastrointestinal illnesses. In Njoro Sub-county, river Njoro and rain water are the primary sources of water which also reduces during dry seasons. Other water sources include boreholes, dams, springs and wells while in other cases, the residents store water in household storage containers for future uses. In this study, various water sources and water stored in different containers in Njoro Sub-County was analyzed for its microbial quality. Various microbial parameters such as total viable colony counts (TVCC), total coliforms (TC) and fecal coliforms (FC) were evaluated by use of the culture methods. Most of the water sources were contaminated. TVCC ranged from 0.47 to 1.76 CFU/1mL in water sources and 0.48 to 2.04 CFU/1mL in domestic storage containers. TC was in the range of between 0.30 to 1.89 CFU/100mL in water sources and 0.59 to 2.47 CFU/100mL in domestic storage containers. The mean FC in water sources ranged from 0.10 to 1.68 CFU/100mL and from 0.81 CFU/100mL domestic storage containers. Therefore frequent water testing should be performed by water authorities as recommended by WHO. At households, the people should employ various water treatment methods and practice safe water handling so as to avoid gastrointestinal infections.
Characterization of Antibioticproducing Actinomycetes Isolated from River Tana and Lake Elementaita in Kenya
(Asian Journal of Research in Biochemistry, 2023-08-01) O. Shikuku, Bonface; Kiruki, Silas; Kuria, Eric; Mutembei, Martin; O. Ogolla, Fredrick
The rise of antibiotic-resistant bacteria has become a global health concern, necessitating the search for novel sources of antibiotics. Actinomycetes, a group of microorganisms, have been known for their ability to produce bioactive compounds with antimicrobial properties. This study aimed to isolate, identify, and characterize antibiotic-producing Actinomycetes from River Tana and Lake Elementaita. Samples were collected from the study sites, and Actinomycetes were isolated using serial dilution and spread plate techniques. The isolates were characterized based on their morphological and biochemical properties. Furthermore, their antibacterial activity against Escherichia coli, Staphylococcus aureus, and Salmonella typhi was evaluated using the agar well diffusion method. The zones of inhibition were measured (mm), and analysis was done to compare the activity of the isolates using Kruskal Wallis test and medians compared using Wilcoxon with Bonferroni correction at alpha = 0.05 in SAS version 9.4. Analysis of DNA sequences was done using the BLAST program and a phylogenetic tree was constructed using MEGA X version 11. Biochemical tests revealed positive results for catalase, indole, oxidase, and citrate utilization, while coagulase and methyl red tests were negative. In terms of antibacterial activity, 54.5% of the isolates showed activity against E. coli, 45.5% against S. aureus, and 45.5% against S. typhi. Isolate LEL2201 had significant (p < 0.05) higher zone of inhibition against S. aureus (inhibition zone of 25.0mm), while isolate RT2201 exhibited the highest activity against E. coli and S. typhi (inhibition zone of 8.5 mm and 8.6 mm, respectively). Molecular characterization through 16S rRNA gene sequencing identified the isolates as belonging to the Actinobacterium order. Phylogenetic analysis revealed their similarity to known Actinomycetes species including Actinomycetales bacterium, Streptomyces intermedius and Streptomyces flavomacrosporus from various countries. The findings of this study demonstrate the presence of antibiotic-producing Actinomycetes in River Tana and Lake Elementaita. Thus, further investigations are warranted to identify and characterize the specific antibacterial compounds produced by these isolates.
Effect of pH, Carbon and Nitrogen Sources on Antibiotic Production by Actinomycetes Isolates from River Tana and Lake Elementaita, Kenya
(Asian Journal of Research in Biochemistry, 2023-08-04) O. Shikuku, Bonface; Kiruki, Silas; Kuria, Eric; Mayo, Domnic; O. Ogolla, Fredrick
The escalating concern over antibiotic resistance and its profound impact on public health have underscored the urgent need to explore alternative reservoirs of antimicrobial agents. In this regard, Actinomycetes have emerged as a compelling area of investigation due to their remarkable capacity to produce bioactive compounds. Therefore, this study sought to investigate the influence of pH and various carbon and nitrogen sources on the antibacterial activity of Actinomycetes isolates collected from Lake Elementaita and River Tana. By examining the effects of these factors, we aimed to gain insights into the optimization of growth conditions and nutrient availability to enhance the production of bioactive compounds with potent antibacterial properties. The Actinomycetes isolates used in this study were from Lake Elementaita and River Tana, known for their diverse ecological characteristics and potential as sources of bioactive compounds. The isolates were subjected to morphological, biochemical, and molecular techniques to ensure accurate identification. To assess the antibacterial activity of the Actinomycetes isolates, they were tested against E. coli using the agar well diffusion method. The independent variables examined in this study were pH levels (4, 7, and 9) as well as different carbon sources (fructose and sucrose) and nitrogen sources (urea and sodium nitrate). The diameter of the inhibition zones served as the dependent variable. The data collected on the effects of pH and nutrients on the inhibition zones of Actinomycetes isolates were subjected to statistical analysis. One-way ANOVA was performed to assess significant differences in antibacterial activity among the isolates under different carbon and nitrogen preference. Mean values were compared using the LSD test at a significance level (α) of 0.05. Furthermore, the Kruskal-Wallis test was utilized to analyze the pH preferences of the Actinomycetes isolates at a significance level (α) of 0.05. The results showed that pH significantly influenced the bioactivity of the Actinomycetes isolates, with pH 7 exhibiting the highest inhibition zones against E. coli. The isolates displayed varied antibacterial activities depending on the carbon and nitrogen sources provided. Sucrose was the most preferred carbon source, followed by fructose, while urea was the preferred nitrogen source, followed by sodium nitrate. The study concluded that pH and nutrient availability play crucial roles in determining the antibacterial activity of Actinomycetes isolates. Other than contributing to our in-depth understanding of the factors influencing the antimicrobial potential of Actinomycetes, the results of this study highlight the importance of optimizing growth conditions and nutrient availability to enhance the production of bioactive compounds with potent antibacterial properties. Further investigations and exploration of Actinomycetes from diverse environments are recommended to discover new bioactive molecules for combating antibiotic resistance.
Perceptions Towards Diagnosis Of Prostate Cancer in Tharaka Nithi County, Kenya
(Journal Of Nursing Practice, 2021-04) Kirungia, Timothy Kinoti; Kirigia, Consolata; Gitonga, Lucy; Kiruki, Silas
Background: Cancers are leading cause of death in developed nations and the second leading cause of death in developing nations. One of the most frequently diagnosed cancers among men is Prostate cancer (PCa). Purpose: This research study aimed at exploring the patient’s and family’s perceptions towards diagnosis of prostate cancer in Tharaka Nithi County, Kenya. Methods: The study population comprised of families and PCa patients attending Chogoria mission hospital, Magutuni sub-county hospital, Chuka county hospital and Tharaka subcounty hospital which were selected purposefully, from which a sample of 70 patients and 65 family members was obtained. Purposive sampling method was used to sample patients and families. Data were collected using interview schedules and focus group discussions and summarized using descriptive statistics. Statistical analysis for association between variables was done using chi-square tests. Results: The study revealed that; men in the age group 60-70 were most prone to the development of prostate cancer. A high percentage of patients and families perceived that prostate cancer was caused by genetic factors and should be treated by medical personnel. Over 50% of the patients and families had no idea of the symptoms of prostate cancer neither had they heard of it before the patient was diagnosed. The study also revealed that 50% of the patients suffered hypertension, 80% did not believe the diagnosis at first and over 50% perceived the diagnosis as a death sentence. PCa patients showed the highest level of acceptance and lung cancer patients the poorest acceptance of illness. Over 90% of the patients and families observed general health improvement after medication. Over 78% of the patients and family‟s had embraced insurance as a way of meeting the medical expenses. Conclusion: This study demonstrated that patients and families perceived the diagnosis of prostate cancer as a death sentence. They also had low level of knowledge about PCa. A strong correlation was demonstrated between family history and increased risk of PCa. However, it was demonstrated that family history of PCa did not increase levels of knowledge on the causes of PCa.
Virulence Gene Markers and Multiple Drug Resistance in Escherichia coli Isolated from River Njoro in Kenya
(2012-11-29) Njeru, S. Ngoci 1,2 *; Kiruki, Silas; Limo, Moses 2; Mbala, M. Jessica 2; Njagi, Eliud Nyaga Mwaniki 3; Okemo, Paul O. 4; Nathan, Lawless 5
The purpose of this study was to investigate the presence of Aeromonas hydrophila at commonly used water collection points on the River Njoro and to determine the in-vitro antimicrobial susceptibility and plasmid profiles of isolates. In total, 126 samples were collected and 36.5% of them were positive for A. hydrophila. The A. hydrophila were recovered on membrane filters, cultured on Trypticase Soy agar, Bile aesculin agar and Aeromonas Medium agar. They were further characterized using cytochrome oxidase and API 20E tests. Detection of drug susceptibility was determined using modified disc diffusion method to ampicillin (25 μg), cefaclor (30 μg), ceftizoxime (30 μg), cefixime (5 μg), cefazidime (30 μg), gentamicin (200 μg), streptomycin (25 μg), chloramphenicol (50 μg), nalidixic acid (30 μg) and ciprofloxacin (1 μg). Most of the isolates showed multi-drug resistance to two or more antibiotics. Chloramphenicol, nalidixic acid, ciprofloxacin, cefazidime and cefixime were the most sensitive drugs with 100% efficacy whereas ampicillin, cefaclor and streptomycin were the most resistant drugs having 100, 67 and 50 resistance, respectively. There was low resistance against ceftizoxime (16.7%) and gentamicin (23.3%). These results indicates that all A. hydrophila isolated from River Njoro had complete resistance to ampicillin and showed variable resistance to cefaclor, streptomycin, gentamycin and ceftizoxime. R-plasmids were extracted from multi-drug resistance strains and separated by agarose gel (0.8%) electrophoresis for profiling. Plasmid profiling revealed that most of the multi-drug resistant isolates contained one plasmid of 21.0 kb. Although some strains exhibited different antimicrobial resistance patterns, all of their plasmids were of the same size (21.0 kb). However, there were no plasmids in the antimicrobial sensitive isolates. This study also indicates that plasmid 21.0 kb is common in A. hydrophila and is important for antimicrobial resistance and virulence. Further studies are required to ascertain the role of this plasmid as a virulence marker.