Browsing by Author "Du Toit, Elloise"

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    The development of probiotics for use in the ostrich farming industry in South Africa
    (2011) Du Toit, Elloise; Reid, Sharon J
    Ostrich farming in South Africa is an important industry but it often suffers from high mortality rates among the ostrich chicks. This is thought to be due in part to environmental stress, leading to the delay in the development of the microbiota, thus making invasion by pathogens likely. Very little is known about the microorganisms inhabiting the ostrich gastrointestinal tract, however they do play an important role in humans and animals and disturbance of this community can be fatal. It has been established that probiotic bacteria such as Lactobacillus and Bifidobacterium spp. play an important role in the health of the host. In order to discover novel probiotic strains, bacteria should be isolated from the host, identified, characterised in-vitro to screen their potential suitability, and finally these results should be confirmed in-vivo. The aim of this study was to follow these guidelines in order to find a successful probiotic mix to decrease the mortality observed on ostrich farms, and to compare the effects of the probiotic mix to that of the antibiotic, tylosin, on the microbiota of the gastrointestinal tract (GIT).
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    The use of molecular diagnostic methods to improve the detection of the common bacterial and viral causes of community acquired meningitis in children in South Africa
    (2015) Khumalo, Jermaine; Bamford, Colleen; Du Toit, Elloise
    With conventional methods of diagnosis, substantial overlaps are common due to an absence of the expected CSF findings clearly aligning to bacterial or viral infection. Reduced sensitivity is commonly observed chiefly due to empiric antibiotic treatment leading to bacterial culture negative results. This leads to costly hospital admissions and unnecessarily prolonged treatment for the unexplained aetiology, further compounded by routine viral diagnostics not being commonly implemented for meningitis diagnosis. We developed and validated in-house quantitative real-time (qPCR) multiplex assays to test for bacterial causes namely: Neisseria meningitidis (ctrA gene), Haemophilus influenzae (hpd gene) and Streptococcus pneumoniae (lytA gene) and viral causes namely: enterovirus (5' UTR), herpes simplex (UL30 gene) and mumps virus (Fusion protein gene). The qPCR assays were carried out on the Biorad CFX 96 real-time instrument. These validated assays were used to screen a cohort of suspected meningitis cases. The retrospective study included 300 paediatric patients aged from 60 days-12 years, over a 1-year period (November1, 2012 to November 30, 2013) with suspected meningitis presented to the outpatient departments of the Red Cross War Memorial Children‟s Hospital (RCCH) in Cape Town. Cerebrospinal fluid with abnormal chemistry and cell counts was selected and total nucleic acid was extracted with the QIAsymphony virus/bacterial DSP kit (QIAGEN, Valencia, CA). The median age of children was 19 months (IQR: 6-65 months). Among the screened 291 CSF samples, 7 (2.4%) cases Gram stain results were obtained along with relatively few cases with positive bacterial culture growth 4/291 (1.4%). Based on bacterial qPCR results, 8 (2.7%), 3 (1%) and 1 (0.3%) were positive for S. pneumoniae, N. meningitidis and H. influenzae respectively. A majority of cases were viral positives with enteroviruses being the dominant at 91/291 (31.3%) and mumps virus 3/291 (1%). No herpes simplex DNA was detected. The bacterial qPCR showed a sensitivity and specificity of 85.7% and 97.7% respectively when compared against a composite reference standard (CRS). We report an improvement with additional detected causes of bacterial meningitis and highlight the burden of the common viral causes. However, a large proportion of cases (63.6 %) have aetiology still unknown. PCR shows valuable in concluding viral aetiology in routine diagnosis.