Magister Scientiae - MSc (Medical BioSciences)

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https://hdl.handle.net/10566/17104

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Browsing by Author "Africa, Charlene"

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    Induction of metronidazole and clindamycin resistance in gardnerella vaginalis
    (University of the Western Cape, 2023) Belford, Robyn Beth; Africa, Charlene
    Bacterial vaginosis (BV) is known to be the most common polymicrobial vaginal disorder in females of childbearing age. It is characterised by a change in the healthy vaginal microbiome, from an environment dominated by hydrogen-producing lactobacilli, to the overgrowth of opportunistic pathogenic bacteria particularly Gardnerella vaginalis. G. vaginalis is a gram-variable pleomorphic bacterium which under normal conditions is considered to exhibit low virulence. G. vaginalis is the most common bacterial species isolated from patients with BV, and isolated in over 98% of BV cases. BV and other infections associated with G. vaginalis are typically treated with metronidazole or clindamycin. There has recently been an increase in recurrent BV infections and treatment failure. Antimicrobial resistance in bacteria has proven to lead to higher rates of adverse health outcomes. Understanding the susceptibility and resistance mechanisms of G. vaginalis is crucial in reducing the number of recurrent infections and treatment failures. Ten commercially acquired G. vaginalis type strains were tested in this study. The Kirby-Bauer and E-Test protocols were performed to determine the antibiotic susceptibility of selected strains and the minimum inhibitory concentrations (MIC) of metronidazole and clindamycin respectively.
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    Prevalence and characterization of Gardnerella vaginalis in pregnant mothers with a history of preterm delivery
    (University of the Western Cape, 2012) Stemmet, Megan; Africa, Charlene; Dept. of Medical BioSciences
    Risk factors such as intrauterine and vaginal infection put pregnant women at risk for delivering preterm. Bacterial vaginosis (BV) is a polymicrobial clinical syndrome commonly diagnosed in women of reproductive age, with women of African descent with low socioeconomic status and previous preterm delivery at high risk. Although frequently isolated from healthy women, Gardnerella vaginalis has been most frequently associated with BV. There is limited data available on the prevalence of BV in Southern Africa; therefore, we embarked on a study to determine the prevalence of BV and G. vaginalis in predominantly black communities in the Western Cape, in order to establish the role of G. vaginalis in BV. Women attending various Maternity and Obstetrics units (MOU) in the Cape Peninsula with and without a history of pre-term delivery (PTD) were invited to participate in the study. Several factors were statistically associated with pregnancy history, including location of study population, parity, smoking and presence of clinical symptoms. The presence of G. vaginalis was determined by culture in 51.7% of the preterm delivery group (PTDG) and 44% of the full-term delivery group (FTDG) women. BV was detected in 31.13% of PTDG and 23.67% of FTDG by Gram stained analysis according to Nugent scoring criteria, with age and HIV status posing as risk factors. When comparing PTDG and FTDG for an association between the presence of G. vaginalis and BV, a stronger association was observed in the PTDG but it was not statistically significant. In both PTDG and FTDG, G. vaginalis was isolated significantly more often in women diagnosed with BV at 24.5% (p < 0.05). Antibiogram studies revealed both Metronidazole and Clindamycin resistant strains of G. vaginalis. G. vaginalis Biotype 7 is specifically associated with BV, while Biotype 2 appears to be associated with BV in women with a history of PTD. Accuracy of diagnostic tools were tested and it was determined that Nugent scoring is more sensitive in diagnosing BV (76.04%), but culture for G. vaginalis is more specific (83.21%). Although this study was limited in that we were unable to follow-up pregnancy outcomes, we were able to confirm the perceived role of G. vaginalis in BV.
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    The Prevalence of Members of the “Red Complex” in Pregnant Women as Revealed by PCR and BANA Hydrolysis.
    (University of the Western Cape, 2005) Bayingana, Claude; Africa, Charlene; Dept. of Medical BioSciences; Faculty of Science
    Increased levels of oestrogen and progesterone during pregnancy may lead to periodontal disease. The anaerobic Gram-negative bacteria called red complex (Porphyromonas gingivalis, Tannerella forsythensis and Treponema denticola) are frequently associated with periodontal disease. Periodontopathogens produce toxins and enzymes which can enter the bloodstream and cross the placenta to harm the foetus. The response of the mother’s immune system to infection by these periodontopathogens, brings about the release of inflammatory mediators which may trigger preterm labour or result in low birth-weight infants. The purpose of this study was to examine the prevalence of red complex, using BANA and PCR in subginginval plaque samples from pregnant women. Subgingival plaque samples were obtained from pregnant women between the ages of 17 to 45 years attending a Mitchells Plain ante-natal clinic. Plaque samples were analyzed by the enzymatic BANA-test for detection of the presence of red complex and DNA was extracted and analyzed using 16 rDNA-Polymerase Chain Reaction (PCR). Seventy-nine percent of pregnant women showed gingival index scores of ≥ 1 of which 74.24% harboured by at least one of the members of the red complex. P.gingivalis was the most prevalent of the three members of the red complex. Findings of this study confirmed a need for dental preventive measures in pregnant women and microbial monitoring of suspected periodontopathogenes. This could be achieved by joint cooperation between Maternity Obstetric Units (MOU), Dentistry and oral microbiology departments. The results of this study revealed that although PCR is more sensitive than BANA in detecting members of the red complex, BANA showed a better association with the indices used to diagnose periodontal disease.
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    The prevalence, risk factors and serotypes of GBS in Libyan women at labour and the rate of vertical transmission of GBS from mother to infant
    (University of the Western Cape, 2022) Elmahaishi, Lubna Mohamed Said; Africa, Charlene
    Group B Streptococcus (GBS) also known as Streptococcus agalactia, is one of the most important causes of serious neonatal infections. Early detection of GBS colonisation in the mother is thus of primary importance to prevent neonatal infection.We assessed 200 pregnant women at labour at Said Hospital in Misrata, Libya between July 2020 and May 20201. Two samples (vaginal samples and rectal samples) were collected from 100 mothers delivering preterm and 100 mothers delivering full term, as well as one sample from the infant at birth.
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    Toxicology and molecular epidemiology of microbes detected in surface water in the Western Cape: The Impact of Informal Settlement
    (University of the Western Cape, 2013) Maboza, Ernest J.M.; Africa, Charlene
    Informal settlements are often implicated in surface water pollution with faecal matter. In most instances faecal pollution in the associated surface waters persists despite improvements in sewage removal infrastructure. This study evaluates the importance of investigating the water quality of the Plankenbrug River before it reaches Khayamnandi settlement by comparing water quality in spring and in winter upstream (Pre-Khayamnandi) and downstream (Post- Khayamnandi) from the settlement. In this study, faecal indicator bacteria (Escherichia coli and total coliforms) were enumerated using Chromocult agar. E. coli was further characterized with analytical profiling index (API) and haemolysis assays. Both Pre- and Post-Khayamnandi were not significantly different from each other for both total coliforms and E. coli in winter. Pre-Khayamnandi had between 105 and 108 cfu/100 ml for total coliforms while Post-Khayamnandi had total coliform colony count between 106 and 107 cfu/100 ml. E. coli also exhibited a similar pattern with slightly higher counts at Post-Khayamnandi with colony counts from 104 to 107 and 105 to 107 cfu/100 ml. Spring microbial count demonstrated a significant difference to winter counts within each test site (p ≤ 0.01) and across the two sites (p ≤ 0.05). Both total coliforms and E. coli were 102 fold higher at Post-Khayamnandi than at Pre-Khayamnandi in spring. The API assay demonstrated significant difference (p ≤ 0.05) between the two test sites. Pre- Khayamnandi predominantly had two different profiles while Post-Khayamnandi had three. These profiles represented five distinct E. coli biotypes. Sorbitol and sucrose tests within the API assay demonstrated significant differences (p ≤ 0.05) between the two test sites. The prevalence of sorbitol fermenters at Pre-Khayamnandi was 100% while at Post-Khayamnandi it was 73%. Pre-Khayamnandi also demonstrated a significantly higher prevalence of sucrose fermenters than Post-Khayamnandi at 100% and 59% respectively. These differences indicated dissimilar sources of faecal contamination around these sites. Differences in the distributions of sorbitol and sucrose fermenting biotypes demonstrate different toxicity potentials across these two test sites. The haemolysis assay demonstrated that 9% of isolates were haemolytic with reference to both known α- and β-haemolyitic streptococci at Post-Khayamnandi. At Pre-Khayamnandi there was a higher percentage of α- and β-haemolyitic species, 29% and 28%, respectively. Post- Khayamnandi and Pre-Khayamnandi were significantly different from each other with reference to both α- and β-haemolysis (p ≤ 0.05). These haemolytic activities also demonstrate different toxicity potentials across the two sites. In conclusion Khayamnandi contributes to an already heavy faecal load in the Plankenbrug River. Thus remedial measures to maintain high surface water quality of Plankenbrug River should be directed upstream from the Khayamnandi settlement as well as within the settlement equally. This study recommends integration of microbial loads with programs such as the National Microbial Monitoring Program of South Africa to drive prioritization process in directing reclaiming of water quality, inter alia.