Caroline Wangari Ngugi

Dr. Caroline Wangari Ngugi

Jomo Kenyatta University of Agriculture and Technology, Nairobi, Nairobi City, Kenya
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 August 2022 in Viruses
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Amos Lucky MhoneAmos Lucky Mhone
Amos Lucky Mhone
AMAngela Makumi
Angela Makumi
JOJosiah Makhandia Odaba
Josiah Makhandia Odaba
LGLinda Guantai
Linda Guantai
DGDamitha Gunathilake
Damitha Gunathilake
NSNicholas Svitek
Nicholas Svitek
Multi-drug resistant (MDR) Salmonella enterica Enteritidis is one of the major causes of foodborne illnesses worldwide. This non-typhoidal Salmonella (NTS) serovar is mainly transmitted to humans through poultry products. Bacteriophages (phages) offer an alternative to antibiotics for reducing the incidence of MDR NTS in poultry farms. Phages that survive the harsh environment of the chicken gastrointestinal tract (cGIT), which have low pH, high temperatures, and several enzymes, may have a higher therapeutic or prophylactic potential. In this study, we analysed the stability of 10 different S. Enteritidis phages isolated from Kenyan poultry farms in different pH-adjusted media, incubation temperatures, as well as simulated gastric and intestinal fluids (SGF and SIF, respectively). Furthermore, their ability to persist in water sources available in Kenya, including river, borehole, rain and tap water, was assessed. All phages were relatively stable for 12 h at pHs ranging from 5 to 9 and at temperatures ranging from 25 °C to 42 °C. At pH 3, a loss in viral titre of up to three logs was observed after 3 h of incubation. In SGF, phages were stable for 20 min, after which they started losing infectivity. Phages were relatively stable in SIF for up to 2 h. The efficacy of phages to control Salmonella growth was highly reduced in pH 2- and pH 3-adjusted media and in SGF at pH 2.5, but less affected in SIF at pH 8. River water had the most significant detrimental effect on phages, while the other tested waters had a limited impact on the phages. Our data suggest that these phages may be administered to chickens through drinking water and may survive cGIT to prevent salmonellosis in poultry.

28 March 2024 in Veterinary Medicine and Science
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SKSarah Kabui
Sarah Kabui
JKJosephine W. Kimani
Josephine W. Kimani
CNCaroline Wangari Ngugi
Caroline Wangari Ngugi
JKJohn Kagira
John Kagira
Background: Ruminant mastitis continues to be a cause of economic losses in the dairy industry and remains a major public health hazard globally.Objectives: This cross‐sectional study was carried out in Mukurweini Sub‐County of Nyeri County, Kenya, to investigate the prevalence of bacteria causing mastitis, risk factors associated with goat mastitis and the antibiotic resistance profiles of bacteria isolated from the goat milk.Methods: Farm level data on risk factors for mastitis was obtained from 56 farmers using a semi structured questionnaire. A total of 189 goat milk samples were collected. The goat's udder was observed for signs of clinical mastitis and the California Mastitis Test (CMT) used to test the milk for sub‐clinical mastitis. All samples were then cultured for morphological identification of bacteria and strain typing by Matrix Assisted Laser Desorption/Ionization (MALDI)‐Time of Flight (ToF) technique. Antimicrobial susceptibility of the isolated Staphylococcus aureus, coagulase‐negative Staphylococcus (CoNS), Escherichia coli, Klebsiella oxytoca, Pseudomonas spp., Enterobacter spp., Proteus vulgaris and Escherichia vulneris to eight commonly used antibiotics was done by the disc diffusion method and validated by determining the presence of antibiotic resistance genes (mecA and blaTEM) using polymerase chain reaction method.Results: The prevalence of clinical mastitis was 1.1% (2/189) while that of sub‐clinical mastitis was 84.7% (160/189). Higher (p < 0.05) prevalence of mastitis was observed in goats whose houses were cleaned fortnightly and in cases where farmers used same towel to dry different does’ udders during the milking process. Thirteen different bacterial species were isolated from the milk samples and identified by MALDI‐ToF, and these included S. aureus (22.0%), CoNS (20.3%), E. coli (18.1%), Pseudomonas spp. (14.3%), Enterobacter spp. (10.4%), K. oxytoca (6.0%), E. vulneris (1.7%), P. vulgaris (1.7%), Raoutella ornithinolytica (1.7%), Stenotrophomonas maltophilia (1.1%), Pantoea agglomerans (1.1%), Serratia marcescens (1.1%) and Cedeceas spp. (0.6%). One hundred pathogenic bacterial isolates were randomly selected and tested for antibiotic sensitivity to eight antibiotics out of which S. aureus were 97.5% resistant to Oxacillin and 100% sensitive to Ciprofloxacin. The CoNSs were 100% resistant to Oxacillin and 100% sensitive to Ciprofloxacin. E. coli were 93.9% resistant to Oxacillin, 69.7% sensitive to Ciprofloxacin and 87.9% sensitive to both Amoxicillin/Clavulanic acid and Meropenem. The antimicrobial resistant genes detected in S. aureus and E. coli were mecA [66.7%, 0%], and blaTEM [20% and 78.3%], respectively.Conclusion: In conclusion, the study showed that most of the does were affected by subclinical mastitis with the main causative bacteria being Staphylococci spp. and coliforms. Farmers need to be trained on improved control of mastitis by adoption of good milking practices and use of CMT kit for early detection of mastitis. Occurrence of multidrug resistance by key mastitis causing pathogens was shown to be prevalent and therefore there is need for development of intervention strategies.

24 April 2024 in Biochemical and Biophysical Research Communications
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Closed access
JPJoseph Kasyoki Peter
Joseph Kasyoki Peter
RURyusuke Umene
Ryusuke Umene
CWChia-Hsien Wu
Chia-Hsien Wu
YNYasuna Nakamura
Yasuna Nakamura
NWNorito Washimine
Norito Washimine
TITsuyoshi Inoue
Tsuyoshi Inoue

21 January 2020 in bioRxiv
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LMLucy Muthoni Mwai
Lucy Muthoni Mwai
MKMutinda Mutinda Kyama
Mutinda Mutinda Kyama
CNCaroline Wangari Ngugi
Caroline Wangari Ngugi
EWEdwin Walong
Edwin Walong
Gold nanoparticle (AuNP) bioconjugates are increasingly being utilised in biomedicine due to their low toxicity on biological tissues and unique electronic and chemical properties. They have been utilised in several biological applications namely manufacture of nanomaterials, biosensing, electron microscopy and drug delivery systems. Particularly, immuno-assays often employ gold nanoparticles (AuNPs) to enhance detection of a biological component. This paper presents a study on the bioconjugation of AuNPs with Horse Radish Peroxidase conjugated Human Papilloma Virus 16/18 Early 6 antibodies (CIP5) against Early 6 (E6) oncoprotein that is overexpressed in cervical carcinoma progression through physical adsorption. This bioconjugate can be employed in diagnostic immunoassay for cervical cancer screening. The study also demonstrated that the antibody pI, gold colloidal solution pH and amount of antibody determine the generation of stable Antibody–AuNPs bioconjugates.

19 February 2026 in Toxins
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VMValentine Musabyimana
Valentine Musabyimana
JKJohn Kagira
John Kagira
Jacob LubuyaJacob Lubuya
Jacob Lubuya
CNCaroline Wangari Ngugi
Caroline Wangari Ngugi
BMBrian M. Musau
Brian M. Musau
GOGeorge Omondi Oluoch
George Omondi Oluoch
Antivenom administration is currently the only therapy for snakebite envenoming. However, in sub-Saharan Africa, inadequate quality control systems have led to deficits in the availability, accessibility, efficacy and safety of regionally available antivenoms, which, in turn, hinder snakebite treatment and management in the region. To address this impediment to snakebite treatment in Kenya, this study aimed to assess the preclinical neutralising potencies of four different antivenoms previously or currently available in Kenya (SAIMR polyvalent, AFRIVEN, PANAF-PremiumTM and InoserpTM) against key snakes of medical importance in the region, towards establishing a national antivenom quality control laboratory. Venoms were extracted from the Kenyan “big five” medically important snake species: Naja ashei, Naja pallida, Naja nigricollis, Dendroaspis polylepis and Bitis arietans, and their lethal potencies were determined using a murine median lethal dose (LD50) assay. In vitro immunological assays (ELISAs and immunoblotting) and an established preclinical murine in vivo neutralisation assay (median effective dose [ED50]) were used to assess the immunoglobulin-binding and venom-neutralising efficacies of the test antivenoms. In vitro assays revealed high venom-binding titres of SAIMR polyvalent, AFRIVEN and PANAF-PremiumTM, and reactivity to a wide range of venom proteins across the different snake venoms. Contrastingly, InoserpTM antivenom had low binding titres and poor reactivity to the snake venom proteins. These findings were aligned with the in vivo results, where SAIMR polyvalent, AFRIVEN and PANAF-PremiumTM showed potent venom-neutralising efficacies against all the tested snake venoms, while InoserpTM had low potency and failed to neutralise the lethal effects of N. ashei, N. pallida and D. polylepis venoms at the manufacture-claimed doses. Based on these robust preclinical results, we conclude that SAIMR polyvalent, AFRIVEN and PANAF-PremiumTM antivenoms offer considerable potential for the treatment of envenoming by diverse medically important snakes in Kenya. The observed deficiencies with the InoserpTM product highlight the importance of (i) robust, independent preclinical antivenom efficacy testing and (ii) the value of establishing a quality control laboratory to inform local regulatory and procurement decision making.

17 October 2024 in Preprints.org
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SNSylvere Nshimiyimana
Sylvere Nshimiyimana
JKJames Kimotho
James Kimotho
CNCaroline Wangari Ngugi
Caroline Wangari Ngugi
(1) Background: Human papillomaviruses (HPV) are primarily related to cervical cancer around the world. This study presented an in silico design of a chimeric L1/L2 mRNA-based vaccine candidate against a diverse spectrum of human papillomaviruses; (2) Methods: We employed a computational strategy to predict and screen for antigenicity, allergenicity, toxicity, and conservation of immunodominant cytotoxic T cells, helper T cells, and linear B-cell epitopes from the most conserved HPV L1 and L2 proteins. The selected epitope peptides were coupled together with appropriate linkers to create a multi-epitope chimeric peptides. The mRNA-based vaccine was developed by combining an optimized open reading frame with co-translation regulation and co-transcription components; (3) Results: Twenty five (25) non-toxic, non-allergenic, highly antigenic, and conserved epitopes were identified. The final vaccine had a molecular weight of 60161.29 kDa, a theoretical pI of 9.44, and a solubility of 0.451. The mRNA-based vaccine had a stable mRNA structure with a minimum free energy of -731.10 kcal/mol and an estimated molecular weight of 644.98 kDa. The suggested vaccine had no cross-affinity for the human genome and achieved a global population coverage rate of 86.24%. The vaccine demonstrated a stable docking complex and robust interactions with Toll-like receptor 4 (TLR4) with binding affinities of -1377.5 kcal/mol and was capable of stimulating immunoglobulin IgG, IgM, T and B cells lymphocytes, and cytokines by in silico simulation; (4) Conclusion: The vaccine is considered a preventive and therapeutic candidate; however, further in vitro and in vivo tests are needed to prove its safety and efficacy.