Department of Biological Sciences
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Item Plasmid mediated penicillin and tetracycline resistance among Neisseria gonorrhoeae isolates from Kenya(2020) Kivata, Mary Wandia; Mbuchi, Margaret; Eyase, Fredrick; Bulimo, Wallace Dimbuson; Kyanya, Cecilia Katunge; Oundo, Valerie; Mbinda, Wilton Mwema; Sang, Willy; Andagalu, Ben; Soge, Olusegun O.; McClelland, Raymond Scott; Distelhorst, JohnBackground: Treatment of gonorrhea is complicated by the development of antimicrobial resistance in Neisseria gonorrhoeae (GC) to the antibiotics recommended for treatment. Knowledge on types of plasmids and the antibiotic resistance genes they harbor is useful in monitoring the emergence and spread of bacterial antibiotic resistance. In Kenya, studies on gonococcal antimicrobial resistance are few and data on plasmid mediated drug resistance is limited. The present study characterizes plasmid mediated resistance in N. gonorrhoeae isolates recovered from Kenya between 2013 and 2018. Methods: DNA was extracted from 36 sub-cultured GC isolates exhibiting varying drug resistance profiles. Whole genome sequencing was done on Illumina MiSeq platform and reads assembled de-novo using CLC Genomics Workbench. Genome annotation was performed using Rapid Annotation Subsystem Technology. Comparisons in identified antimicrobial resistance determinants were done using Bioedit sequence alignment editor. Results: Twenty-four (66.7%) isolates had both β-lactamase (TEM) and TetM encoding plasmids. 8.3% of the isolates lacked both TEM and TetM plasmids and had intermediate to susceptible penicillin and tetracycline MICs. Twenty-six (72%) isolates harbored TEM encoding plasmids. 25 of the TEM plasmids were of African type while one was an Asian type. Of the 36 isolates, 31 (86.1%) had TetM encoding plasmids, 30 of which harbored American TetM, whereas 1 carried a Dutch TetM. All analyzed isolates had non-mosaic penA alleles. All the isolates expressing TetM were tetracycline resistant (MIC> 1 mg/L) and had increased doxycycline MICs (up to 96 mg/L). All the isolates had S10 ribosomal protein V57M amino acid substitution associated with tetracycline resistance. No relation was observed between PenB and MtrR alterations and penicillin and tetracycline MICs.Item Green synthesis of copper oxide nanoparticles and its efficiency in degradation of rifampicin antibiotic.(Springer, 2023-08-28) Nzilu, Dennis Mwanza; Madivoli, Edwin Shigwenya; Makhanu, David Sujee; Wanakai, Sammy Indire; Kiprono, Gideon Kirui; Kareru, Patrick GachokiIn recent ages, green nanotechnology has gained attraction in the synthesis of metallic nanoparticles due to their cost-effectiveness, simple preparation steps, and environmentally-friendly. In the present study, copper oxide nanoparticles (CuO NPs) were prepared using Parthenium hysterophorus whole plant aqueous extract as a reducing, stabilizing, and capping agent. The CuO NPs were characterized via UV–Vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), powder X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Dynamic Light Scattering (DLS). The UV–Vis spectra of CuO NPs showed a surface plasmonic resonance band to occur at 340 nm. FTIR analysis revealed the presence of secondary metabolites on the surface of CuO NPs, with a characteristic Cu–O stretching band being identified at 522 cm−1. Scanning electron micrographs and transmission electron micrographs showed that CuO NPs were nearly spherical, with an average particle of 59.99 nm obtained from the SEM micrograph. The monoclinic crystalline structure of CuO NPs was confirmed using XRD, and crystallite size calculated using the Scherrer-Debye equation was found to be 31.58 nm. DLS showed the presence of nanoparticle agglomeration, which revealed uniformity of the CuO NPs. Furthermore, the degradation ability of biosynthesized nanoparticles was investigated against rifampicin antibiotic. The results showed that the optimum degradation efficiency of rifampicin at 98.43% was obtained at 65℃ temperature, 50 mg dosage of CuO NPs, 10 mg/L concentration of rifampicin solution, and rifampicin solution at pH 2 in 8 min. From this study, it can be concluded that CuO NPs synthesized from Parthenium hysterophorus aqueous extract are promising in the remediation of environmental pollution from antibiotics. In this light, the study reports that Parthenium hysterophorus-mediated green synthesis of CuO NPs can effectively address environmental pollution in cost-effective, eco-friendly, and sustainable ways.Item Antimalarial pyronaridine resistance may be associated with elevated MDR-1 gene expression profiles but not point mutation in Plasmodium berghei ANKA isolates(African Journal of Biochemistry Research, 2020-08) Kimani, Shadrack Kanyonji; Shume, Jacob ManyiwaThe selection of resistance is inevitable whenever chemotherapy is necessary for pathogen control. Notably, Plasmodium falciparum has developed multifaceted means to overcome the toxicity of nearly all antimalarial medicines. To bypass this challenge, not only should novel drugs be developed, but the resistance mechanisms to new and existing drugs need should be fully explored. Pyronaridine is a companion drug in Pyramax® , a blend of artesunate (ASN)-pyronaridine (PRD) which is the WHO prequalified alternative for malaria treatment in the African setting. However, half-life mismatch predisposes the PRD to swift emergence of resistance especially in high malaria transmission settings. However, there are no well-characterized PRD-resistant parasite lines. Previously, stable PRD- resistant P. berghei ANKA lines were selected by in vivo drug pressure and preliminary results showed crossresistance with quinolines, therefore, hypothetically the activity of PRD and chloroquine or other quinolines may be comparable, hence, the resistance mechanisms may be parallel. Consequently, genetic polymorphisms and expression profiles of PbMDR-1 that could be associated with pyronaridine resistance were examined by PCR amplification, sequencing and transcript quantification by RT-qPCR. The transcripts level increased during resistance selection while translated PbMDR-1 sequence alignment of PRD-sensitive and PRD-resistant was the same, the expression may be linked to PRD resistance but not mutations.Item Knowledge Levels of Breast Cancer Among Women of Reproductive Age in Kenya, a Case Study of Kitui County(Central African Journal of Public Health, 2020) Koech, Cheruiyot Fred; Nzioki, Mativo; Karama, Mohammed; Muinde, Fridah NdindaBackground: Breast cancer is one of the leading causes of mortality among women in the world today. Therefore there is need for concerted efforts to advance interventions that seek to mitigate challenges associated with its screening. In Kenya, breast cancer accounts for 23% of cancerous diseases that affect women. The purpose of this study was to determine the knowledge levels on breast cancer among women of reproductive age in Kitui County, roll out community based health education intervention (CBHI) targeted at enhancing breast cancer knowledge, and finally to assess the effect of the CBHI on knowledge levels. Methods: The study design adopted was quasi-experimental. This was adopted because it enables researchers to evaluate causal relationships when interventions or agents of causation are induced. This study was undertaken with the causal mechanism being the rollout of CBHI and the impact in knowledge of breast cancer. Two groups were evaluated; intervention and control groups. The knowledge among these groups was evaluated between two time intervals; end line and at baseline. Data was collected using questionnaire instruments, analyzed using SPSS v23 and presented in form of tables and frequencies. Inferential analysis was achieved through binary logistic regression and Difference in Difference scores. Results: The individual score analysis on different aspect of breast cancer knowledge and awareness indicated that there was a direct positive impact of the CBHI on the knowledge on breast cancer among the respondents. Significant changes observed upon the implementation of CBHI on breast cancer included; respondents in the intervention group who knew at least two danger signs for breast cancer increased to 3.8 (Adj. OR=3.895, P<0.05, 95%CI: 2.538-5.979), those who knew the age related risks associated with breast cancer increased by 4.1 (Adj. OR=4.128, P<0.05, 95%CI: 2.940-5.797), and finally, those who knew at least one Breast cancer screening method increased 7 fold among the intervention group after the rollout of CBHI (Adj. OR=7.011, P<0.05, 95%CI: 4.138-11.880). Conclusion: The impact of CBHI on knowledge of breast cancer was significant. As a result, more people in the intervention group were cognizant of different warning signs of breast cancer, breast cancer screening methods, and that these opportunities facilitate early detection of breast cancer. The actionable strategies recommended by this study is implementation of community based strategies to enhance knowledge levels on breast cancer in order to improve screening uptake and therefore early detection of breast cancer.Item Antimalarialpyronaridine resistance may be associated with elevated MDR-1 gene expression profiles but not point mutation in Plasmodium bergheiANKA isolates(African Journal of Biochemistry Research, 2020-08) Kimani, Shadrack Kanyonji; Shume, Jacob ManyiwaTheselectionofresistance is inevitable whenever chemotherapy isnecessaryforpathogencontrol. Notably, Plasmodiumfalciparum has developed multifacetedmeans to overcomethetoxicityof nearly allantimalarial medicines. To bypass this challenge,not only should novel drugs be developed, but the resistance mechanisms tonewandexisting drugs need should be fullyexplored.Pyronaridine is a companion drug inPyramax®, a blend of artesunate (ASN)-pyronaridine (PRD) whichistheWHOprequalifiedalternative for malariatreatment in the Africansetting. However, half-life mismatch predisposes thePRDto swiftemergence of resistanceespeciallyin high malaria transmission settings. However, there are no well-characterized PRD-resistant parasite lines. Previously, stable PRD-resistant P. bergheiANKA lines were selected by in vivo drug pressure and preliminary results showed cross-resistance with quinolines, therefore, hypothetically theactivityof PRDand chloroquine or other quinolinesmay be comparable, hence, the resistance mechanisms may be parallel. Consequently, genetic polymorphisms and expressionprofiles of PbMDR-1 that could be associated with pyronaridine resistance wereexamined by PCR amplification, sequencingand transcript quantification byRT-qPCR.The transcripts level increased during resistanceselectionwhiletranslated PbMDR-1sequence alignment of PRD-sensitive and PRD-resistant was the same, theexpressionmay be linked toPRD resistance but not mutations