Biology subjects

Kanoi, B. N.

Publications and source records attributed to Kanoi, B. N..

4 recordsLinked to original sources

bioRxiv2026

Genomic characterization of Escherichia coli and Enterobacter hormaechei clinical isolates from a tertiary healthcare facility in Kenya

Extended-spectrum beta-lactamase-producing Enterobacterales such as Escherichia coli and Enterobacter hormaechei represent a growing public health challenge in clinical settings, particularly in low-and middle-income countries, due to the escalating threat of antimicrobial resistance (AMR). In this study, we aimed to identify the antibiotic resistance genes present in E. coli (n=4) and E. hormaechei (n=3) clinical isolates. Multidrug-resistant phenotypes were confirmed using disc diffusion assays against 20 antibiotics. Whole-genome sequencing of resistant isolates was performed using Oxford Nanopore Technologies. Genome assembly and analysis revealed high-risk clones, including sequence type (ST) 1193 in E. coli and ST78 in E. hormaechei. All E. coli isolates harbored the blaCTX-M gene in their chromosomes along with point mutations conferring resistance to fluoroquinolones, while E. hormaechei isolates encoded blaACT in their chromosomes. Additionally, both species carried plasmids with multiple antibiotic resistance genes, including blaOXA and blaTEM, co-located with metal resistance operons, indicating the potential for horizontal gene transfer. BLAST analysis revealed high sequence similarity between the plasmids identified in clinical isolates and those previously recovered from environmental sources, highlighting the role of environmental reservoirs in AMR dissemination. Notably, no carbapenem resistance genes were detected in any isolate. These findings underscore the growing threat posed by multidrug-resistant Enterobacterales in clinical settings and emphasize the urgent need for strengthened infection prevention and control measures to mitigate AMR spread.

bioinformatics↗

bioRxiv2024

Placental malaria is associated with a TLR-Endothelin-3-oxidative damage response in human placenta tissues

Placental malaria, which is mainly caused by the sequestration of Plasmodium falciparum- infected erythrocytes in the placenta, is an important driver of poor pregnancy outcomes, including fetal growth restriction, preterm birth, and stillbirth. However, the mechanisms underlying its adverse outcomes are unclear. Mouse models have shown that placental malaria triggers a proinflammatory response in the placenta, which is accompanied by a fetal Toll-like receptor (TLR)4-mediated innate immune response associated with improved fetal outcomes. Here, we used hematoxylin and eosin staining to identify placental malaria positive and negative samples in our biobank of placentas donated by women living in a malaria-endemic region of Kenya and assessed the impact of placental malaria on the expression of TLRs, Endothelins, and oxidative damage. RT-qPCR analysis revealed that placental malaria was associated with an upregulation of TLR4, TLR7, and Endothelin-3. Moreover, immunohistochemistry showed that placental malaria was associated with elevated expression levels of the oxidative DNA damage marker, 8- hydroxy-2-deoxyguanosine, while RT-qPCR revealed that this was accompanied by an upregulation of p21, an inhibitor of cell cycle progression and marker of cellular response to DNA damage. These findings allude to a novel mechanism of placental malaria pathogenesis driven by a TLR-Endothelin-3-oxidative DNA damage signaling axis.

cell biology↗

bioRxiv2021

Sex differences in concentrations of HMGB1 and numbers of pigmented monocytes in infants with malaria

Females generally mount more robust innate and adaptive immune responses and demonstrate a higher rate of morbidity, and prevalence of autoimmune diseases by comparison with males. In malaria, females demonstrate higher concentrations of antibodies and rates of severe adverse events and mortality following natural infections and malaria vaccination. Although monocytes/macrophages play a crucial role in disease and protection in malaria, no studies have investigated sex differences in their functions in production of proinflammatory cytokines and chemokines in malaria-infected subjects. Here, we show significant sex differences in serum concentrations of HMGB1, a non-histone chromatin-associated protein, and numbers of pigmented monocytes, which are both markers of severe malaria, in infants <5 years old from a malaria endemic region in Northern Uganda. Female infants with clinical malaria had significantly higher HMGB1 concentrations than male infants, and female infants with asymptomatic malaria had significantly lower numbers of pigmented monocytes than male infants with asymptomatic malaria. There was (1) a significant correlation between HMGB1 concentrations and pigmented monocyte numbers in female but not male infants; and (2) a significant correlation between HMGB1 concentrations and parasite densities in female but not male infants. These findings suggest that female infants with clinical malaria might be at a greater risk of morbidity characterized by higher serum HMGB1 levels.

immunology↗

bioRxiv2020

Assessment of microbial communities in Nakivubo wetland and its catchment areas in Lake Victoria Basin, Uganda

Microbial community structure changes are key in detecting and characterizing the impacts of anthropogenic activities on aquatic ecosystems. Here, we evaluated the effect of river pollution of industrial and urban sites on the microbial community composition and distribution in the Nakivubo wetland and its catchment areas in Lake Victoria basin, Uganda. Samples were collected from two industrial and one urban polluted sites and the microbial diversity was analyzed based on a 16S rRNA gene clone library. Differences in microbial diversity and community structure were observed at different sampling points. Bacteria associated with bioremediation were found in sites receiving industrial waste, while a low proportion of important human-pathogenic bacteria were seen in urban polluted sites. While Escherichia spp. was the most dominant genus of bacteria for all sites, three unique bacteria, Bacillus sp., Pseudomonas sp., Thermomonas sp., which have been reported to transform contaminants such as heavy metals and hydrocarbons (such as oils) by their metabolic pathways were also identified. Our results may serve as a basis for further studies assessing microbial community structure changes among polluted sites at Nakivubo Water Channel for management and monitoring. The diversity of natural microbial consortia could also be a rich bioprospecting resource for novel industrial enzymes, medicinal and bioactive compounds.

ecology↗