RP-Department of Biochemistry and Biotechnology
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Item Evaluating Genetic Diversity in Kenyan Pineapple (Ananas comosus) Germplasm Using Sequence-Related Amplified Polymorphism (SRAP) Markers(American Journal of Plant Science, 2025-04) Mwaniki, Lilian Mwende; Wanjala, Bramwel Waswa; Runo, Steven; Omwenga, George; Simiyu, Elphas SambuPineapple (Ananas comosus), a widely cultivated tropical fruit, is known for its global economic and nutritional significance. The study aimed to investigate the genetic diversity of 80 pineapple accessions from Kenya using Sequence-Related Amplified Polymorphism (SRAP) markers. Out of the 48 SRAP primers, six polymorphic primers were identified. Genetic diversity was examined using DARWin, GenAlEx, and PopGene software. DNA (deoxyribonucleic acid) extraction followed a modified CTAB (Cetyltrimethylammonium bromide) method, ensuring quality DNA for analysis. Polymerase Chain Reaction (PCR) was conducted with selected primers to amplify DNA segments, revealing polymorphisms. The findings revealed significant genetic differences among (22%) and within (78%) populations, with a PhiPT value of 0.221, Nei’s gene diversity (H) of 0.1761, and Shannon’s Information index (I) of 0.2699, indicating moderate population differentiation. Principal Coordinates Analysis (PCoA) explained 53.47% of the overall genetic variation, revealing a relatively homogenous genetic composition within accessions. Gene flow (Nm) was 1.3623, suggesting moderate gene flow among populations. The dendrogram grouped samples into two clusters, corroborating the homogenous genetic composition. No differentiation among populations was observed using Nei’s genetic distance matrix. The overall genetic similarity suggests that most populations share a common genetic background. Improving the genetic diversity of Kenyan pineapples is essential for enhancing resilience and sustainability. This can be achieved through collecting local ties, cross-breeding, importing new cultivars, conducting genomic studies, and establishing gene banks. These efforts will help make Kenyan pineapples more adaptable, productive, and resistant to climate change and other challenges.Item PlantGENE Report on Panel Discussion: Advancing Plant Biotechnology in Africa(Springer, 2025) Malzahn Aimee A.; Songstad Nicole; Tripathi Leena; Ihuoma Okwuonu; Sithole‑Niang Idah; Runo Steven; Wagaba Henry; Kouassi Modeste; Kaeppler Heidi; Gordon‑Kamm William; Keunsub Lee; Wayne Parrott; Nigel Taylor; Rogers Christian; Gafney Jim; Van Eck Joyce; Veena VeenaThis report provides an overview of the content and data collected from the “Successes, Challenges, and Opportunities Plant Transformation Research in Africa” panel discussion. Organized by PlantGENE, this event brought together scientists and stakeholders across the globe to examine the complex challenges and emerging opportunities in plant transformation research in laboratories across Africa. The discussion, rooted in insights from a panel of six leading scientists, highlights critical issues including restrictive regulatory environments, prohibitive costs, and the inconsistent availability of essential research materials. Additionally, the pervasive “brain drain” phenomenon, where skilled researchers leave the continent for better opportunities, exacerbates the difculties faced by African scientists. Despite these challenges, the report also identifes signifcant advancements, particularly in the growing recognition of African leadership within universities and national agricultural research systems (NARS). These institutions, supported by highly skilled faculty and motivated graduate students, are producing high-quality research that contributes to global scientifc knowledge. The panelists emphasized the necessity of creating an environment that encourages African scientists to remain on the continent and address local challenges through innovative research. Strengthening intra-African networks and fostering collaborations with the global scientifc community are proposed as essential strategies to achieve this. This report underscores the critical need for substantial investments from both global and African organizations, working with African governments, to support these eforts. Furthermore, it calls for science-based decision-making and fair regulatory frameworks to align with unique opportunities and risks associated with technological advancements in Africa. This paper details the observations of six panelists and analyzes the results of attendee surveys in order to document these challenges and opportunities while advocating for sustained investment and strategic partnerships to build a thriving bioeconomy across Africa.Item Evaluation of Formulated Strigolactone Analogs for Striga Management in Kenyan Agriculture(Elsevier B.V, 2025) Muhammad Jamil; Mutinda Sylvia; Jian You Wang; Barminga Damaris; Mwihaki Agnes; Navangi Lynet; Okiyo Teresa O.; Patil Rohit H.; Ngatia Titus; Mudavadi Patrick; Runo Steven; Al-Babili SalimStriga hermonthica, an obligate root parasitic weed affecting cereal crops, poses a significant threat to global food security in Sub-Saharan Africa (SSA). Germination of Striga seed largely relies on signaling molecules released by the host roots, mainly strigolactones (SLs). Suicidal germination is an effective strategy for reducing Striga seed banks in infested soils by applying SL analogs in the absence of a host. However, the challenge remains in developing suitably formulated SL analogs for field application. In this report, we assessed the activity of two SL analogs, MP3 and Nijmegen-1, in both granular and liquid formulations in laboratory and greenhouse settings, and conducted mini-field and field trials to evaluate their effectiveness under farmers’ conditions, using maize as the host crop in Kenyan agriculture. We observed a significant induction of Striga seed germination reaching up to 56 % in laboratory germination bioassays and a reduction in Striga emergence by up to 77 % in greenhouse pot studies. In mini- and field trials in different infested fields, we recorded up to 80 % and 65 % reduction in Striga emergence, respectively. In conclusion, the formulated SL analogs demonstrate significant potential to reduce Striga infestation in maize fields in Kenya and are promising candidates for use by farmers due to their simplicity, ease of handling, stability, and effectivenessItem Pathogen Dynamism and Variability of Rice Yellow Mottle Virus in Kenya(springer, 2025) Kigaru Antony; Nganga Everlyne M.; Murori Rosemary; Pappu Hanu R.; Runo Steven; Ateka Elijah M.Rice yellow mottle disease (RYMD) continues to constrain rice production in Africa. Rice yellow mottle virus (RYMV), which belongs to the Sobemovirus genus, is the causal agent of RYMD. In Kenya, previous studies on RYMV mostly focused on western Kenya, ignoring the central and coastal regions, which are also important areas for rice cultivation in the country. This has resulted in incomplete data on RYMD outbreaks. This study aimed to determine the prevalence of RYMD in the farmers’ felds, and the genetic diversity of the RYMV based on the coat protein gene. Field surveys were carried out in Kenya’s rice-growing regions between May and July 2023 to determine disease incidences using the IRRI Standard Evaluation Scale (SES) for rice. Symptom observations and serological tests confrmed the presence of RYMV in all surveyed rice cultivation areas. The presence of RYMV was detected in Kirinyaga, Tana River, and Taita Taveta counties of Kenya, representing the feld report of its occurrence in these regions. Disease incidence and severity analysis using one-way ANOVA showed no signifcant diference in RYMD incidence among the rice irrigation schemes (F (6,29)=1.838, P=0.1265). Sequencing results of the coat protein gene (ORF4 region) revealed that the RYMV isolates in this study could be classifed as S4ke, S4ug, and S4mg strains in the East Africa lineage. The discovery of the RYMV strain S4mg in Kenya runs counter to the gradual strain of breaking up and moving away that has been established in Africa over the past two centuries. Results showed that RYMV is present in all the rice-growing regions under study and exhibits intra-strain diversity in Kenya. Incorporating resistance genes into extensively grown rice cultivars is crucial for preventing the spread of the rice yellow mottle virus.Item Cholera in Sub-Saharan Africa: Unveiling Neglected Drivers and Pathways to Elimination(PLOS, 2025) Siamalube Beenzu; Ehinmitan Emmanuel; Runo Steven; Maina Ngotho; Onguso JustusCholera is a virulent infectious disease caused by the Gram-negative, comma-shaped bacteria Vibrio cholerae, after ingesting contaminated food and/or water. If left untreated, it can kill within 5 days. Since mid-2021 the world has recorded a notable increase in the seventh cholera pandemic, with high case fatality rate especially in Sub-Saharan Africa. Oral cholera vaccines are established but not readily available on the market, or if they are, they are not pocket friendly for low-resource-income countries. Hence, with the advent of green factory biotechnology, plant-derived edible vaccines are such a promising approach to supplement conventional vaccine methods. Human travellers are often the major transmitters as they move from region to region. Poor sanitation and inadequate clean water supply are services not readily available in most Sub-Saharan African countries, coupled with insufficient surveillance services, lack of early detection facilities, and the public not having ample awareness concerning sanitation and hygiene. This article highlights the epidemiology of cholera in Africa and expounds on what drives the outbreaks of cholera in this region. The discussion provides an in-depth analysis of the factors leading to the forsaken cholera drivers, emphasizing economic factors, culture, and environmental influences, particularly within the Sub-Saharan African communities. It presents a strategic blueprint approach that includes public health awareness, community participation, government involvement, and exploring emerging research tools. By merging these proposals into a unified context, a collective and practical methodology would be established to tackle the impact of cholera epidemiology that has been sidelined in Sub-Saharan AfricaItem Parasitic plants are models for examining global food security,biodiversity loss and host–parasite evolution, in achanging world(John Wiley & Sons, 2024) Runo Steven; Wicke Susann; Thorogood ChrisParasitic plants devastate crop productivity around the world, threatening food and nutritional security for millions. In this special issue of Plants People, Planet, we provide a systematic analysis of some of the most devastating parasitic plants that threaten global food security focusing on (i) witchweeds, (ii) broomrapes and (iii) vampireweeds. Witchweeds—members of the genus Striga—have earned themselves the nickname ‘cereal killers’ because of their devastating destruction of Africa's most staple cereals, including maize, sorghum, millets and upland rice. Striga is a highly successful parasite, the lifecycle of which is tightly synchronised with that of its host (Runo & Kuria, 2018). Central to this synchronisation is its ability to detect and locate would be hosts through biomolecules—predominantly strigolactones—emitted from the host (Al-Babili & Bouwmeester, 2014; Matusova et al., 2005). Ironically, the reliance of Striga on strigolactones (SLs) is also its Achilles' heel as this presents opportunities for control through manipulation of communication exchange. One approach involves growing Striga alongside a false host that releases SLs, which trigger Striga germination but fail to support its growth or infection (Khan et al., 2011). Another method uses germination stimulants applied to bare fields to induce Striga germination without a host (Jamil et al., 2022, 2024; Kountche et al., 2019). These methods are referred to as ‘suicidal germination’. Additionally, breeding host crops that produce insufficient or less potent SLs can also help manage Striga infestations. These strategies have made SLs a central focus of research for Striga control...Item In vivo antidiabetic and ex-vivo antioxidant activities of dichloromethane extract of Xerophyta spekei(springer, 2025) Ndile,Michael Musila; Makori, Wycliffe Arika; Kibiti,Cromwell Mwiti; Ngugi,Mathew PieroBackground The medicinal plant Xerophyta spekei is used among Embu and Mbeere communities to manage diabetes mellitus. However, its efficacy has never been evaluated in vivo. The purpose of this study was to investigate its quantitative phytochemical and antidiabetic potential. Extraction was done using Dichloromethane (DCM). Quantitative phytochemical analysis was conducted using GC-MS. To evaluate antidiabetic activity, groups of mice which included normal control, diabetic control, positive control, and extract-administered groups (50, 100, 150, and 200 mg/kg body weight) were used. Alloxan monohydrate was used to induce diabetes. Blood glucose of the mice was determined hourly for the first six hours, and once after 12 and 24 h on the first day. Thereafter, the blood glucose in mice was determined once a week for three weeks. During the experimental period of three weeks, body weights were determined. After 21 days, lipid profiles, kidney and liver function tests as well as ex vivo antioxidant assays were carried out. Results The phytochemicals classes identified included flavonoids, phenolic compounds, phytosterols, terpenoids, fatty acids, tocopherols and alkaloids. Stigmasterol had the highest concentration (12.99±2.56 mg/g). The extract decreased blood glucose dose-dependently, with 200 mg/kg bw dose resulting in the highest % mean change (40.10±0.95). The extract gradually decreased blood glucose during 21 days of treatment. It attenuated loss of body weight and aberrant biochemical parameters including liver and renal function tests as well as lipid profiles in diabetic mice. Furthermore, it reduced levels of malondialdehyde and enhanced enzymatic antioxidant activities in diabetic mice. Conclusions The study confirms that DCM extract X. spekei contains phytochemicals with antioxidant and antidiabetic properties. The findings authenticate the folkloric use of X. spekei in managing diabetes mellitus. The medicinal plant also serves as a potential source for developing antidiabetic agents.Item Simple and Fail-safe Method to Transform Miniprep Escherichia coli Strain K12 Plasmid DNA Into Viable Agrobacterium tumefaciens EHA105 Cells for Plant Genetic Transformation(bio-protocol, 2025) Siamalube,Beenzu; Ehinmitan,Emmanuel; Maina Ngotho; Onguso,Justus; Runo,StevenAgrobacterium-mediated gene transformation method is a vital molecular biology technique employed to develop transgenic plants. Plants are genetically engineered to develop disease-free varieties, knock out unsettling traits for crop improvement, or incorporate an antigenic protein to make the plant a green factory for edible vaccines. The method’s robustness was validated through successful transformations, demonstrating its effectiveness as a standard approach for researchers working in plant biotechnology. It enables the introduction of foreign DNA into plant genomes. Conventionally, plant genetic transformation has relied on time-consuming, costly, and technically demanding procedures, such as electroporation and chimeric viruses or biolistic methods, which usually yield variable transformation efficiencies. This study presents a simple and fail-safe protocol that involves a modified freeze-thaw and heat-shock concoction method. This approach involves a streamlined plasmid miniprep procedure to isolate high-quality plasmid DNA from Escherichia coli K12 strain, followed by a target-specific transfer into A. tumefaciens EHA105 strain. The optimized method minimizes DNA degradation and maximizes uptake by Agrobacterium cells, making it a reproducible and accessible protocol for various genetic engineering applications. The transformation efficiency is consistently high, enhancing plasmid uptake while maintaining cell viability, requiring minimal specialized equipment and reagents. The proposed protocol offers significant advantages, including simplicity, reliability, and cost-effectiveness, positioning it as a valuable alternative to traditional techniques in the field of plant biotechnology.Item Callosobruchus Maculatus: An Abiotic Enemy to Pigeon Pea Productivity(IJSRT, 2025) Katoo,Athanas Alexander; Ngugi,Mathew; Gitahi,StephenThe cowpea (pigeon pea) weevil, Callosobruchus maculatus, is a significant pest of stored pulses, particularly affecting crops like cowpea and pigeon pea in tropical and subtropical regions. This review examines the biology, life cycle, and the damaging effects of C. maculatus on stored pigeon pea grains. The insect undergoes a holometabolous life cycle, with rapid development influenced by temperature and humidity, which allows for multiple generations during a single storage season. The damage caused by C. maculatus includes direct feeding on seeds, resulting in weight loss, reduced seed viability, and compromised nutritional quality, along with contamination from insect frass and remains, further degrading the grains' marketability and safety. The economic impact is substantial, particularly in regions where pigeon peas are a staple crop, affecting food security and farmers' livelihoods. Control measures for C. maculatus include a combination of cultural, physical, chemical, and biological strategies. These include proper storage practices, the use of inert materials like diatomaceous earth, irradiation, low temperature treatments, and chemical controls, each with their advantages and limitations. Integrated pest management, utilizing multiple strategies, is essential for effective control and minimizing losses.Item Molecular Analysis of Human Respiratory Syncytial Virus Group B Strains Isolated in Kenya Before and During the Emergence of Pandemic Influenza A/H1N1(John Wiley & Sons, 2025-02) Wangui,Julia; Gachara, George; Mobegi,Victor; Agoti, Charles; Otieno,James; Opanda,Silvanos; Opot,Benjamin; Ngeranwa,Joseph N.; Njeru,Regina; Bulimo,WallaceBackground: We conducted a retrospective study to explore molecular insights into human respiratory syncytial virus (HRSV) group B strains among patients attending outpatient clinics at government medical facilities both prior and during the onset of Influenza A/H1N1/2009 pandemic outbreak. Methods: We screened 2300 nasopharyngeal swabs using multiplex real time reverse transcriptase polymerase chain reaction. We amplified a segment of the first and second hypervariable regions, as well as the conserved portion of the third domain of the G-gene using HRSV-B specific primers, sequenced by Sanger di-deoxy chain termination method and thereafter analyzed the sequences. Results: We characterized the circulating strains into three known genotypes: SAB4 (1.4%), BA7 (1.4%), and multiple variants of BA9 (97.2%). The majority of BA9 viruses were uniquely Kenyan with only 4% aligning with BA9 lineages found elsewhere. The mean evolutionary rate of the HRSV-B was estimated to be 3.08×10−3 substitutions per site per year. Conclusion: Our findings indicate that the circulating HRSV-B viruses in Kenya underwent a slower evolution during the pe riod of 2007–2010. Additionally, our findings reveal the existence of a unique lineage as well as new variants that have not been reported elsewhere to date.Item Evaluation of Growth and Yield of New Papaya (Carica Papaya L.) Hybrid Lines and Their Performance Against Moroccan Watermelon Mosaic Virus‐Causing Disease(John Wiley & Sons, 2024) Kosgei,Janet Chepng’etich; Asudi,George O.; Ombwara,Francis Kweya; Kariuki,Lilian W.; Rimberia,Fredah K.The production of Carica papaya L. in Kenya is seriously affected by the Moroccan watermelon mosaic virus and lack of improved varieties leading to the importation of expensive seeds for the resource‐scarce farmers. To curb these challenges, new papaya hybrid lines were recently selected and bred, but their growth traits and performance against papaya diseases were not evaluated. Therefore, we assessed the growth, development, and production characteristics of these new hybrid lines 1–8, with Sun rise Solo as control using the International Board of Plant Genetic Resources papaya descriptor in the field at the Jomo Kenyatta University of Agriculture and Technology, Juja. The hybrid trees matured 6–15 days before Sunrise Solo and fruited at heights of 23–37 cm lower than controls at the end of the harvesting stage, showing they could be harvested longer than the controls. Hybrid line 4 had larger fruits preferred for local markets and industrial use, while hybrid lines 1, 2, 5, 7, and 8 and Sunrise Solo had smaller and medium‐sized fruits suitable for exports. However, only hybrid lines 6 and 7 showed more tolerance to MWMV disease and powdery mildew. Therefore, normal agronomic practices are important for seed multiplication purposes to improve papaya production in Kenya.Item Transcriptome Atlas of Striga Germination: Implications for Managing an Intractable Parasitic Plant(ppp, 2023) Irafasha,Gilles; Mutinda, Sylvia; Mobegi,Fredrick; Hale,Brett; Omwenga,George; Wijeratne, Asela J.; Wicke,Susann; Bellis,Emily S.; Runo,StevenSocietal Impact StatementWitchweeds, parasitic plants of the genus Striga, are nicknamed “cereal killers”because of their devastating destruction of Africa's most staple cereals, includingmaize, sorghum, millets, and upland rice. The parasite relies on biomolecules emittedfrom the host roots to germinate and therefore initiate its infectious lifecycle. Somesorghum varieties have evolved to not produce effective germination stimulants,making them resistant to the parasite. Here, the genetic factors that underpin Strigagermination were assessed, followed by a discussion of how such knowledge can beused to develop new Striga management strategies through the disruption of host–parasite communication exchange.Summary• Seeds of the parasitic plant Striga are dormant. They only germinate in responseto biomolecules emitted from the host's root exudate, strigolactones (SL). But it isnow emerging that Striga germination is a much more complex process regulatedby crosstalk of hormone signaling pathways.• To further understand the genetic basis of the communication exchange betweenStriga and its host sorghum, we performed a comparative transcriptomic analysis.We sought to identify major transcriptomic changes that define the germinationprocess in Striga and a set of genes that may contribute to the differences in ger-mination rates.• Results showed that germination proceeds immediately after SL perception and ismarked by a wave of transcriptional reprogramming to allow for metabolic pro-cesses of energy mobilization. Cluster analysis using self-organizing maps revealeda time-phased and genotype-differentiated response to germination stimulation.The variation in germination was also a function of hormonal crosstalk. The earlygermination stage was associated with significant repre....Item Validity of Procalcitonin and C-Reactive Protein as Biomarkers in Diagnosis Ofneonatal Sepsis in a Referral Hospital, Kenya(Alexandria Journal of Medicine, 2024-11) Tum, Florence Chepyegon; Ngeranwa, Joseph J.N.; Maiyoh, Geoffrey K.; Frank G. OnyambuBackground: Neonatal sepsis (NS) is a significant health concern causing high morbidity and mortality among neonates. The clinical symptoms of NS can overlap with other common neonatal conditions. The gold standard diagnostic method, the blood culture test, has numerous limitations including lengthy turnaround time, which delays appropriate management of NS. Acute phase protein; procalcitonin (PCT) and C-reactive protein (CRP) tests have emerged as potential alternatives due to short turnaround times, high sensitivity, and specificity in detecting NS. Nevertheless, there is limited data on their usability in Kenyan public hospitals. This study, therefore, was conducted to validate the performance of PCT and CRP tests in diagnosis of NS locally. Methodology: Blood samples were collected from 196 neonates with suspected sepsis admitted at Moi Teaching and Referral Hospital (MTRH). Blood culture was performed using BacT/ALERT blood culture system. Bacteria growths were identified and antibiotic susceptibility for the isolates determined using Vitek II. Serum PCT levels were determined using the chemiluminescence immunoassay method. Serum CRP levels were measured using Immunoturbidimetry method. Results: Growth of organisms occurred in 45.4% of the sepsis suspected neonates. The sensitivity, specificity, positive predictive value, negative predictive value and area under the curve for PCT were 93.3%, 98.1%, 97.6%, 94.6% and 0.959, whereas for CRP they were 100%, 72.8%, 74.3%, 100%, and 0.953, respectively. Conclusion and Recommendation: The CRP test exhibited superior sensitivity, negative predictive value, but lower specificity, making it a more valuable tool for ruling out NS. Overall, however, PCT emerged as a more robust biomarker, offering a reliable balance between sensitivity and specificity, indicating its ability to identify cases with NS correctly. The area under the ROC curve confirms that CRP and PCT have high accuracy in detecting NS. The study recommends adoption of PCT and CRP biomarkers in the diagnostic protocols for NS.Item In Vitro Anti-Prostate Cancer Efficacy and Phytochemical Composition of the Dichloromethane and Ethyl Acetate Leaf Extracts Of Vitex Doniana (Sweet)(Frontiers in Pharmacology, 2024-11) Moriasi, Gervason; Ngugi, Mathew; Mwitari, PeterBackground: Prostate cancer is a significant global health concern, particularly among ageing male populations, with a disproportionately higher burden in subSaharan Africa. Conventional treatments, though effective, are costly and cause devastating side effects which limit their clinical benefits. Hence, this study evaluated the in vitro antiprostate cancer properties and secondary metabolites of dichloromethane and ethyl acetate lead extracts of Vitex doniana to explore safer and efficacious natural alternatives based on ethnomedicinal claims. Methods: Phytochemical profiling was conducted using gas chromatographymass spectrometry (GC-MS) analysis to identify secondary metabolites in the extracts. The cytotoxic effects of the extracts were determined through the MTT assay using Vero CCL-81 cells and DU-145 cells. The expression profile of the selected genes (ar, bcl2, caspase-3, cdk1, and p53) in DU-145 cells treated with the study extracts was investigated using RT-qPCR. Results: GC-MS analysis revealed 10 secondary metabolites in the dichloromethane extract and 27 secondary metabolites in the ethyl acetate extract of V. doniana leaves, with the majority being sesquiterpenes, diterpenoids, and phytosterols. The dichloromethane and ethyl acetate leaf extracts of V. doniana exhibited low cytotoxicity against normal mammalian epithelial cells (Vero CCL-81), with CC50 values of 1,238.85 μg/mL and 964.81 μg/ mL, respectively. Besides, the ethyl acetate leaf extract of the studied plant demonstrated potent anti-prostate cancer activity against DU-145 cells, with an IC50 of 35.68 μg/mL and a high selectivity index (SI) of 27.04. Likewise, the dichloromethane leaf extract of this plant displayed cytotoxic effects (IC50: 287.01 μg/mL) and a selectivity index of 4.32. The reference drug (Doxorubicin) showed a higher toxicity against Vero CCL-81(IC50: 0.41 μg/mL) and DU-145 (IC50: 0.28 μg/mL) cells and a lower selectivity index of 1.46. The DU145 cells treated with the studied plant extracts exhibited notable upregulation of ar and bcl2, and normalization of caspase 3, cdk1 and p53 expression. Conclusion: The studied plant extracts possess in vitro anti-prostate cancer properties and could be promising candidates for further preclinical studies aimed at developing novel botanical-based therapies for the management of prostate cancer.Item Gastrointestinal Carriage of Carbapenemase-Producing Enterobacterales among Inpatient and Outpatient Children in Kenya(Springer Nature, 2024-12) Githii, Susan; Maingi, John M.; Nyaga, Teresia; Ndungu, Cecilia; Nyongesa, Kelvin Wangira; Musyoki, Abednego MokiGastrointestinal carriage of antimicrobial-resistant bacteria, especially carbapenemase-producing Enterobacterales (CPE), presents a critical public health threat globally. However, in many resource-constrained countries, epidemiological data on CPE is limited. Here, we assessed gastrointestinal carriage and associated factors of CPE among inpatient and outpatient children (≤ 5 years). This hospital-based cross-sectional study was conducted at Thika Level 5 Hospital in Kenya from February to June 2023. In total, 540 participants were recruited from outpatient (270) and inpatient (270) children, excluding those admitted for < 48 h and outpatients with ≤ 3 months hospitalization history. Demographic data were collected using a questionnaire, and stool or swab samples were cultured following standard microbiology methods. Automated platforms were used for isolates identification and antimicrobial susceptibility testing. Gastrointestinal carriage rate of CPE was 9.6%, 95% confidence interval (CI): 6.39–13.79% (26/270) among the inpatients and 5.9%, 95% CI: 3.42–9.45% (16/270) among the outpatients. The carbapenemase-producing Enterobacterales were predominated by multidrug-resistant Escherichia coli from inpatients (22/22, 100%) and outpatients (8/10, 80%). The colonization rate was higher among inpatients who were presenting with chills (aOR = 10.57, p = 0.008). We report a high gastrointestinal carriage of CPE among children (≤ 5 years). Strict adherence to colonization screening, and antimicrobial stewardship policies are critical to control CPE dissemination in the current study area and beyond.Item The Persistent Challenge of Cholera in Africa: A Complex Interplay of Factors(RPHB, 2024-12) Siamalube, Beenzu; Ehinmitan, Emmanuel; Runo, Steven; Onguso, Justus; Maina, NgothoCholera remains a formidable public health challenge across Africa, disproportionately impacting marginalized and vulnerable populations [1]. The disease's persistence underscores its multifaceted nature, rooted in more than just the biological characteristics of Vibrio cholerae. Instead, it reflects a complex interplay of environmental, social, economic, and systemic factors, each compounding the difficulty of effective prevention and control [1,2]. Africa continues to bear the highest burden of cholera globally, with recurring outbreaks that cause significant morbidity and mortality, often overwhelming already fragile healthcare systems [3]. The disease frequently strikes regions plagued by inadequate access to clean water, sanitation, and hygiene (WASH) infrastructure [3,4]. These deficiencies create fertile ground for the bacterium's proliferation, particularly in densely populated urban slums and rural areas with limited public health outreach. Climate change further exacerbates the problem, with extreme weather events such as floods and droughts creating conditions conducive to cholera outbreaks [5].Item Leveraging the Complex Interplay between Arbuscular Mycorrhizal Fungi, Seasonal Dynamics, and Genotypic Diversity to Optimize Maize Productivity in Semi-Arid Agroecosystems(Heliyon, 2024-09) Kipkorir, Koech; Koskey, Gilbert; Njeru, Ezekiel Mugendi; Maingi, JohnMaize production under low-input agricultural systems in semi-arid areas of Sub-Saharan Africa faces significant challenges, primarily stemming from the synergistic impacts of climate vari ability and suboptimal agronomic practices. Harnessing soil microbiota, particularly arbuscular mycorrhizal fungi (AMF), represents a pivotal strategy for bolstering low-input systems. However, their functional utility is contingent upon their compatibility with the prevailing environmental conditions and biotic interactions. This study examines the influence of two distinct AMF in oculants on the growth and yield attributes of diverse maize genotypes across varying seasons within semi-arid regions of Kenya. We hypothesized that AMF inoculants exhibit differential adaptability to varying environmental sites and seasons, and their interaction will enhance the provision of key ecosystem services important for maize production. Field experiments were conducted in three semi-arid Counties (Tharaka-Nithi, Embu, and Kitui) during the 2019/2020 cropping seasons. A randomized complete block design with three replications and three treat ments was adopted. Treatments consisted of Rhizatech (a commercial AMF inoculant), a con sortium of AMF isolates (Rhizophagus irregularis and Funneliformis mosseae), and a non-inoculated control. In season one, notable interaction effects were observed for both site × maize genotype (p = 0.0007) and site × AMF inoculation (p < 0.0001), whereby Duma 43 genotype had the highest yield in Embu (11.93 t ha− 1 ) and Kitui (11.76 t ha− 1 ) counties, and Rhizatech and con sortium inoculation consistently led to elevated grain yields across all three genotypes in Kitui, surpassing non-inoculated controls. AMF inoculation notably augmented phosphorus (P) uptake, with Rhizatech demonstrating a 79.7 % increase and consortium showing a 38.7 % increase in shoot P content compared to control plants in season 1. These findings highlight the complex interplay between AMF effectiveness, seasonal variations, and maize diversity. Further research is needed to elucidate the underlying mechanisms driving these seasonal shifts, allowing for opti mized AMF inoculation strategies for improved maize performance under diverse conditions.Item Isolation of phages against Streptococcus species in the oral cavity for potential control of dental diseases and associated systemic complications(Archives of Microbiology, 2024) Chepchumba, Beatrice; Asudi, George. O.; Katana, Japhet; Ngayo, Musa. O.; Khayeli, Juliah AkhwaleDental infections and systemic complications caused by Streptococcus species in the oral cavity are increasingly exhibiting resistance to commonly used antibiotics, posing a potential threat to global public health. Phage therapy may ofer a supe rior alternative, given that bacteriophages can be easily isolated and rapidly replicate in large numbers. In this study, six Streptococcus species from the oral cavity were characterized. Bacteriophages isolated from wastewater using five of these species as hosts produced plaques ranging from 0.2 to 2.4 mm in size. The phages demonstrated stability within a temperature range of 4 ℃ to 37 ℃. However, at temperatures exceeding 45 ℃, a noticeable reduction in bacteriophage titer was observed. Similarly, the phages showed greater stability within a pH range of 5 to 10. The isolated phages exhibited latency periods ranging from 15 to 20 min and had burst sizes varying from 10 to 200 viral particles. This study supports the potential use of bacteriophages in controlling infections caused by Streptococcus species.Item Characterization of Anopheles Funestus Larval Habitats in Kenya: Insights into Malaria Vector Ecology and Control(European Journal of Ecology, 2023) Omondi, Clifton; Nonoh, James; Ntabo, ReginaThe breeding of malaria-spreading vectors such as Anopheles funestus is influenced by various environmental factors that contribute indirectly to the transmission of the Plasmodium parasite. However, there is limited knowledge of larval habitat ecology that hinder prevention and control of mosquito-borne diseases. This study aimed to charac terize larval habitats based on physicochemical and habitat characteristics, considering the abundance of A. funestus. A cross-sectional survey method was used to collect data on the established transects. Physical parameters (water temperature, pH, conductivity, and total dissolved solids) were measured using a 5-in-1 meter probe. Levels of chem ical parameters (sulphate, COD, and BOD) were determined in the laboratory using standard methods. Observations were also made on habitat characteristics (including watercolor, habitat size, and canopy). There was significant effect (P<0.05) of conductivity, pH, sulphate, COD, and BOD on the number of A. funestus larvae. Water samples with a high population of A. funestus larvae were found to have higher conductivity (Me of 470.5), TDS (Me = 235), and pH levels (Me of 6.71). Conversely, water samples with a high population of non-Anopheles funestus larvae were found to have higher COD (Me of 843.20), BOD (Me of 367.2), and SO4 levels (Me of 11.3). A significant correlation (p<0.5) existed between A. funestus larvae and physical water parameters. For instance, Anopheles funestus larvae was high (Me of 36.85) in stagnant water and in semi-permanent water (Me of 47.37). The study demonstrates that both physico chemical and habitat parameters significantly influence the abundance of Anopheles funestus larvae in larval habitats. Parameters such as conductivity, pH, total dissolved solids, sulphate, COD, BOD, watercolor, depth, distance from the homestead, and habitat size were found to be important in determining the presence of A. funestus larvae. Therefore, vector control strategies should include larval source management by targeting rivers and other water bodies to prevent the emergence of Anopheles funestus.Item In Vivo Antidiarrheal Effect and Phytochemical Characterization of Plectranthus Barbatus Andrews(JABET, 2024-01) Ajwang, Emmah Clarice; Ngugi, Mathew Piero; Omwenga, George Isanda; Muruthi, Carolyn WanjiraDiarrheal infections remain a public health problem. The mainstays of pharmacological therapy for infectious diarrhea include probiotics, antibacterials, and intestinal adsorbents. Nevertheless, these clinical treatments are not devoid of shortcomings including prohibitive costs and adverse effects. Medicinal plants including Plectranthus barbatus (P. barbatus) have folkloric remedies against diarrhea. However, there is paucity of knowledge to scientifically validate the efficacy of P. barbatus on diarrheal infections. The study was undertaken to ascertain antidiarrheal efficacy, bioactive composition, and toxicity profiles of P. barbatus extracts. Antidiarrheal activity and acute toxicity were carried out on Swiss albino mice. Quantitative phytocompound analysis was evaluated using liquid chromatographymass spectrometry (LCMS). Results indicated that P. barbatus extract has antidiarrheal activity whereby it prolonged the start of diarrhea, causing a decline in the occurrence of wet feces and intestinal transit significantly. Additionally, the extract reduced the accumulation of intraluminal fluid resulting in decrease in distension, intestinal overload, and water content in the fecal drops. Also, acute toxicity assay on mice showed that P. barbatus extract was non-toxic at the dosage level of 2000mg/kgbw. In addition, LCMS analysis detected presence of phytocompounds associated with antidiarrheal effects including forskolin, gallic, kaempferol, and quercetin. Findings from the current study offer a scientific validation for the folkloric utilization of P. barbatus in the management of diarrhea.