Isoniazid and Rifampicin Tuberculosis Drug Resistance in HIV Endemic Region of Western Kenya

Background: Tuberculosis drug resistance is often associated with inadequate anti-tuberculosis treatment regimen resulting to mutations that confers resistance to anti-tuberculosis agents. This is aggravated by synergetic relationship between Tuberculosis and HIV (Human Immunodeficiency Virus). Over 25% of Global Tuberculosis deaths occur in Africa and Kenya is one of the 30 high burden countries that together account for more than 80% of the world’s TB cases. According to World Health Organization, in 2018, Multi drug resistant Tuberculosis prevalence in Kenya was 1.3% in new cases and 4.4% in retreatment cases. Kisumu County recorded the second highest HIV prevalence at 18.6% against the national prevalence of 4.5% in 2020. The extent of regional burden of DR-TB and HIV co-infection has not been exactly well-defined in Western Kenya.Methods: This was a prospective cross sectional study that aimed to explore the association between Tuberculosis drug resistance and HIV status among new and previously treated pulmonary tuberculosis cases in Kisumu County, Kenya. Tuberculosis clinical suspects were recruited into the study and classified as HIV positive or negative based on their clinical data. Sputum samples from tuberculosis clinical suspects were subjected to fluorescent microscopy, phenotypic culture and line probe assay.Results: Out of a sample of 256, response rate was 216 of which HIV positive cases were 119(55.1%) and negative were 97 (44.9%). The study found that out of 11 that were phenotypic Isoniazid resistance 8(6.7%) were from HIV positive cases while 3 (3.2%) were from HIV negative cases. Phenotypic rifampicin resistance among the HIV positive were 8 (6.7%) while HIV negative were 2 (2.1%). All the 2(1.7%) MDR cases were from HIV positive participants. The study found out that HIV status and Tuberculosis cases were significantly associated at p<.05. HIV positive cases were more likely associated with retreatment cases (OR=1.4,95CI:1.00-1.90) compared to new cases.The study found out that the common mutant probe among the HIV positive was katG MUT1 4(2.6%), while mutant probes among the HIV negative were in hA MUT1 1(0.7%), katG MUT1 1(0.7%) and roB MUT2A 1(0.7%). Wild type gene deletion among the HIV positive cases were observed in probes katG WT 3(2.1%), roB WT7, katG WT 1(0.7%) while wild type gene deletion among the HIV negative cases were inhA WT1 1(0.7%), in hA WT1/inhAWT2 1(0.7%), katG WT 1(0.7%).Conclusion: Interventions specific to HIV-endemic areas are urgently needed to block tuberculosis drug resistance transmission. Development and improvement of the efficacy of interventions will require a greater understanding of the transmission of multidrug-resistant tuberculosis in HIV-endemic settings like Kisumu County, Western Kenya

Electrochemical analysis of selected polychlorinated biphenyls and contaminated water remediation using polyaniline coated sawdust

Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2012.Polychlorinated biphenyls (PCBs) are known harmful chemicals which require urgent remediation, monitoring and assessment in the environment. The predominant current methods used to analyze PCBs involve expertise and are cost intensive. Most of these methods are chromatographic based techniques which are difficult to sustain in Africa due to the expensive nature of the instrument, costly running expenses and skilled labour required. These limitations face Africans, who are the most affected by the presence of PCBs in their environment as a result of improper disposal and usage of these compounds

Synthesis and characterization of bimetallic silver and platinum nanoparticles as electrochemical sensor for nevirapine, an anti-HIV drug

Thesis (DTech (Chemistry))--Cape Peninsula University of Technology, 2016.Bimetallic silver-platinum (Ag-Pt) nanoparticles (NPs) were synthesized via simultaneous reduction of varying mole fractions of metal precursors H2PtCl6.6H2O and AgNO3 by sodium citrate. Kinetics rates of were as follows; Ag NPs (0.079 s-1), Ag-Pt NPs 1:1 (0.082 s-1) and Pt NPs (0.006 s-1). The UV visible spectrum of Ag NPs exhibited a characteristic absorption band while Pt NPs and Ag-Pt bimetallic NPs exhibited no absorption peaks. Successful formation of both monometallic and bimetallic NPs was confirmed via transmission electron microscopy (TEM); selected area electron diffraction (SAED) and energy dispersive X-ray (EDX) analysis. TEM images depicted core-shell arrangement in the bimetallic (BM) NP ratios (1:1, 1:3 and 3:1) with an average particle size of 21 nm. The particle size trend where monometallic Ag NPs (60 nm) > Pt NPs (2.5 nm) while in the BM ratios Ag-Pt NPs 1:1 (25 nm) > Ag-Pt NPs 1:3 (20.7 nm). X-ray diffraction (XRD) patterns depicted crystallinity in all the synthesized NPs with confirmation of the face centred cubic structure formation. Transducers were fabricated by drop casting the nanoparticless on the glassy carbon electrode (GCE) and their electrochemical properties studied via cyclic voltammetry (CV). High diffusion coefficient (D) and surface coverage reported were Ag NPs (6.70 cm2 s-1, 54.49 mol cm-2 ) and Ag-Pt NPs 1:1 (0.62 cm2 s-11.85 mol cm-2). Electrochemical band gaps ranged from 1.45 to 1.70 eV while the Tauc’s model band gaps of nanoparticles were found in the range of 2.48 to 3.84 eV. These band gaps were found to be inversely proportional to particle size, which was attributed to the quantum confinement effect. Both optical and electrochemical band gap portrayed similar trend as well as an increase in the BM NP relative to monometallics. These nanoparticles band gaps are within semiconductor range for most materials. The electrochemical behaviour and surface characteristics were studied using 0.1 M PBS solution by scan rates variations for the diffusion coefficient determination of modified electrodes which ranged from 0.62 to 6.10 x 10-5 cm2 s-1. Laviron’s approach for parameters such as apparent charge transfer rate constant, ks, and charge transfer coefficient, α, for electron transfer between NPs and GCE were investigated using CV. The values of electron-transfer coefficients ranged from 0.1 to 0.7 while the charge transfer rate constant values ranged from 0.74 to 31.13 s-1

Electrochemical characterization of silver-platinum various ratio bimetallic nanoparticles modified electrodes

Silver-platinum (Ag-Pt) bimetallic nanoparticles (NPs) with varying mole fractions (1:1, 1:3 and 3:1) were prepared by co-reduction of hexachloroplatinate and silver nitrate with sodium citrate. Upon successful formation of monometallic and bimetallic (BM) core shell nanoparticles, cyclic voltammetry (CV) was used to characterize the NPs. The drop coated nanofilms on the GC electrode showed characteristic peaks of monometallic Ag NPs; Ag+/Ag0 redox couple as well as the Pt NPs; hydrogen adsorption and desorption peaks. Varying current trends were observed in the BM NPs ratios as; GCE/Ag-Pt NPs 1:3 > GCE/Ag-Pt NPs 3:1 > GCE/Ag-Pt NPs 1:1. Fundamental electrochemical properties such as; diffusion coefficient (D), electroactive surface coverage, electrochemical band gaps and electron transfer coefficient (α) and charge (Q) were assessed using Randles - Sevcik plot. High charge and surface coverage was observed in GCE/Ag-Pt NPs 1:3 accounting for its enhanced current. GCE/Ag-Pt NPs 3:1 showed high diffusion coefficient while GCE/Ag-Pt NPs 1:1 possessed high electron transfer coefficient, which is facilitated by its heterogeneous rate constant relative to other BM NPs ratios. Surface redox reaction was determined as adsorption controlled in all modified GCEs

Kinetics and morphological analysis of silver platinum bimetallic nanoparticles

Kinetics of a one-pot core–shell synthesis of bimetallic (BM) silver–platinum (Ag–Pt) nanoparticles (NPs) by simultaneous reduction of 1:1 mol fraction of precursors H2PtCl6·6H2O and AgNO3 in aqueous solution is reported. Kinetics analysis was done by plotting UV–visible absorptions versus reaction time with a first-order fitting. Recorded constants of Ag NPs (0.079 s−1), Ag–Pt NPs 1:1 (0.082 s−1), and Pt NPs (0.006 s−1) were obtained. The NPs suspension solutions were clear, free from AgCl precipitate, and had characteristic optical properties of 450 nm (Ag NPs), while there were no observable bands for Pt and BM NPs. Morphological analysis using transmission electron microscopy, energy-dispersive X-ray spectroscopy (EDX), and selected area electron diffraction (SAED) depicted spherical aggregates of Ag NPs, Pt NPs and core shell Pt–Ag NPs 1:1 of average size of 60, 2.5, and 20 mm, respectively. Presence of the Ag and Pt elemental composition in the nanoparticle suspensions was confirmed by EDX. SAED ring patterns revealed a single face-centered cubic crystalline nature of Ag NPs and showed typical Pt-based BMs randomly overlapped ring pattern with sharp diffraction spots.Cape Peninsula University of Technology for funding and DAAD German

Potential of silver nanoparticles functionalized polyaniline as an electrochemical transducer

Modification of commercial platinum (Pt) and glassy carbon (GC) electrodes with polyaniline (PANI) and silver nanoparticles doped polyaniline (PANI/Ag NPs) through electropolymerization of aniline in the absence and presence of Ag NPs in 1 M hydrochloric acid (HCl) was interrogated. Fourier transform infrared (FTIR) and transmission electron microscope (TEM) techniques were used for structural, compositional and morphological elucidation. FTIR spectra for PANI and PANI/Ag NPs had the characteristic PANI functional groups as well as desired bands for the conducting emeraldine (EM) form. The predominance of the PANI pattern in the spectra is indicative of the intact PANI structure in the presence of Ag NPs while the slight band shifts are signify interfacial interactions between PANI and Ag NPs. TEM micrograms depicts different size one dimensional nanofibric tubes of the supramolecular structures of PANI. Ag NPs functionalized PANI had larger smoother tubes, suggesting organized morphology arrangement. An increased energy dispersive spectroscopy (EDS)-TEM count from 256 to 277 confirms incorporation of Ag NPs in PANI. GC/PANI/Ag NPs exhibited outstanding electroactivity (higher conductivity and rate of electron transfer).This might be a result of the large surface coverage, film thickness and diffusion coefficient as a result of the large GC surface area. Possibly, the improvement might be due to the GC electrode properties. The electroactivity of the electrodes increased in the order: Pt < GC < Pt/PANI < Pt/PANI/Ag NPs < GC/PANI < GC/PANI/Ag NPs. The effect of Ag NPs in the polymer was demonstrated by ultimate band gap reduction of PANI and enhanced magnitudes of current response per electrode

Thermal and spectroscopic dynamics of titanium oxide functionalized polyaniline coated sawdust

Natural cellulose (sawdust) usage is limited by its poor physical and chemical properties. This study looks into the effects of chemical treatment of sawdust with polyaniline. Polyaniline (PANI) was chemically polymerized in situ from aniline in acid medium containing sawdust and/or titanium oxide (TiO2) to form polyaniline composites (PANI/SD, PANI/SD/TiO2 and PANI/SD/TiO2). These composites spectrophotometric, structural, morphological and thermal properties were determined using various spectrophotometric techniques such as fourier transform infrared (FTIR), UV-visible, transmission electron microscope (TEM), thermogravimetric (TG) and differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). Results indicate structure retention by the polyaniline, Sawdust and titanium oxide. However, minor chemical shifts were indicative of a physio-chemical interaction between the functional groups. The marked morphological changes observed from the pure chemicals and composites suggests multi-layer formation. Thermal studies showed two weight loss waves; 1st waves are due to water and doping material loss while 2nd wave losses are a result of polymer decomposition. The weight loss trend was: PANI/SD < PANI < PANI/SD/TiO2 < PANI/TiO2, thus suggesting a thermal stability improvement with the addition of TiO2. Powder X-ray diffraction confirmed the structural retention of pure polyaniline and sawdust as indicated by the appearance of their representative broad 2θ angles at 20°, 26° and 15°, 24°.Cape Peninsula University of Technolog

Electrochemical behaviour of silver nanoparticle-MWCNTs hybrid nanostructures synthesized via a simple method

As the synthesis via completely green method is emerging, determination of the electrochemistry properties of the as-synthesized nanomaterials has become an important aspect of research. We herein investigate for the first time the inherent electrochemistry of silver nanoparticle modified multiwall carbon nanotubes (Ag NPs-MWCNTs) hybrid nanocomposites that was synthesized via a simple method using cyclic voltammetry (CV) as a diagnostic technique. The result obtained was compared with multiwall carbon nanotubes (MWCNTs), acid functionalized MWCNTs (MWCNT-COOH) and as-synthesized silver nanoparticle (Ag NPs) modified on the glassy carbon electrode (GCE). A detailed analysis of the cyclic voltammograms gave fundamental electrochemical parameters including the transfer coefficient (α) and the diffusion coefficient (D). The transfer coefficient for the Ag NPsMWCNTs/GCE was found to be greater than that of MWCNTs/GCE while the diffusion coefficient of Ag-NPs-MWCNTs/GCE was calculated to be 5.11 ×10-5 cm 2 s -1 which is higher than both pristine MWCNTs/GCE and MWCNT-COOH/GCE.The authors thank the Department of Science and Technology (DST Nano mission (SR/NM/NS- 54/2009)), National research foundation (NRF) South Africa, under the Nanotechnology Flagship Programme (NFP, Grant no: 97983) for financial support. The financial support from UGCGovernment of India through SAP and DST -Government of India through FIST and PURSE programme are also gratefully acknowledg

High seroprevalence of Immunoglobulin G (IgG) and IgM antibodies to SARS-CoV-2 in asymptomatic and symptomatic individuals amidst vaccination roll-out in western Kenya.

The population's antibody response is a key factor in comprehending SARS-CoV-2 epidemiology. This is especially important in African settings where COVID-19 impact, and vaccination rates are relatively low. This study aimed at characterizing the Immunoglobulin G (IgG) and Immunoglobulin M (IgM) in both SARS-CoV-2 asymptomatic and symptomatic individuals in Kisumu and Siaya counties in western Kenya using enzyme linked immunosorbent assays. The IgG and IgM overall seroprevalence in 98 symptomatic and asymptomatic individuals in western Kenya between December 2021-March 2022 was 76.5% (95% CI = 66.9-84.5) and 29.6% (95% CI = 20.8-39.7) respectively. In terms of gender, males had slightly higher IgG positivity 87.5% (35/40) than females 68.9% (40/58). Amidst the ongoing vaccination roll-out during the study period, over half of the study participants (55.1%, 95% CI = 44.7-65.2) had not received any vaccine. About one third, (31.6%, 95% CI = 22.6-41.8) of the study participants had been fully vaccinated, with close to a quarter (13.3% 95% CI = 7.26-21.6) partially vaccinated. When considering the vaccination status and seroprevalence, out of the 31 fully vaccinated individuals, IgG seropositivity was 81.1% (95% CI = 70.2-96.3) and IgM seropositivity was 35.5% (95% CI = 19.22-54.6). Out of the participants that had not been vaccinated at all, IgG seroprevalence was 70.4% (95% CI 56.4-82.0) with 20.4% (95% CI 10.6-33.5) seropositivity for IgM antibodies. On PCR testing, 33.7% were positive, with 66.3% negative. The 32 positive individuals included 12(37.5%) fully vaccinated, 8(25%) partially vaccinated and 12(37.5%) unvaccinated. SARs-CoV-2 PCR positivity did not significantly predict IgG (p = 0.469 [95% CI 0.514-4.230]) and IgM (p = 0.964 [95% CI 0.380-2.516]) positivity. These data indicate a high seroprevalence of antibodies to SARS-CoV-2 in western Kenya. This suggests that a larger fraction of the population was infected with SARS-CoV-2 within the defined period than what PCR testing could cover