Woulter Le Roux - Academia.edu (original) (raw)
Uploads
Papers by Woulter Le Roux
Water SA, 2018
+27 12 ��1������� �a��� +27 12 ��1�2����� ��1������� �a��� +27 12 ��1�2����� �� �a��� +27 12 ��... more +27 12 ��1������� �a��� +27 12 ��1�2����� ��1������� �a��� +27 12 ��1�2����� �� �a��� +27 12 ��1�2����� ��1�2������� e�mail�� mdupree��csir.co.�a mdupree��csir.co.�a
South African Journal of Science, 2013
Impact of solar irradiation on cholera toxin secretion by different strains of Vibrio cholerae Ch... more Impact of solar irradiation on cholera toxin secretion by different strains of Vibrio cholerae Cholera toxin is the aetiological agent of cholera-a deadly waterborne disease acquired through the consumption of untreated water contaminated with CTXФ bacteriophage harbouring strains of V. cholerae. Solar disinfection is a re-emerging technique that relies on the ultraviolet component of sunlight to inactivate the growth of Vibrio cholerae in water, rendering the water microbiologically safe for consumption. However, studies have shown that DNA damaging agents, such as ultraviolet light, induce the replication of the CTXФ bacteriophage with subsequent expression of the cholera toxin. In this study we investigated the impact of solar irradiation on the secretion of cholera toxin by toxigenic strains of V. cholerae in water. The cholera toxin ELISA assay, qualitative and quantitative real-time PCR as well as growth on solid media were used to determine cholera toxin secretion, DNA integrity and growth of the bacteria after 7 h and 31 h of solar irradiation. Solar irradiation in water reduced the integrity of DNA, inactivated the growth of V. cholerae and, most importantly, prevented the secretion of detectable levels of cholera toxin. This finding is encouraging for resource-poor communities that may rely on solar disinfection to alleviate the burden of cholerarelated fatalities. In this study we investigated the potential for sunlight to induce the secretion of cholera toxin by toxigenic strains of V. cholerae by means of solar irradiating the microorganisms in water. Material and methods Vibrio cholerae strains and culture conditions Seven strains of V. cholerae-six toxigenic and one non-toxigenic-were used in this study: NCTC 5941 and NCTC 12945 obtained from the national collection of type cultures; BRITS01 isolated from Brits, South Africa; G4222
Rural households are o�ten dependent on rivers, springs, boreholes or standpipes some distance �r... more Rural households are o�ten dependent on rivers, springs, boreholes or standpipes some distance �rom their homes �or their daily water requirements. Water �or drinking and domestic use is consequently stored in containers in�house which are prone to post�collection contamination. The objective o� the study was to determine the most likely origin or place o� introduction o� E. coli associated with post�collection contamination in rural households, by assessing the degree o� genetic relatedness o� E. coli present in the stored water and other environmental samples. E. coli isolates were obtained using either mFC agar with confirmation of indole production (44 isolates) or Colilert ® -18 (52 isolates). Amplified fragment length polymorphism (AFLP) fingerprinting was applied to determine the genetic relatedness of E. coli isolated �rom in�house storage containers, drink� ing cups, hand-swab samples, cattle dung and from the source water (spring water). DNA fingerprints of E. coli produce...
Water SA, 2018
+27 12 ��1������� �a��� +27 12 ��1�2����� ��1������� �a��� +27 12 ��1�2����� �� �a��� +27 12 ��... more +27 12 ��1������� �a��� +27 12 ��1�2����� ��1������� �a��� +27 12 ��1�2����� �� �a��� +27 12 ��1�2����� ��1�2������� e�mail�� mdupree��csir.co.�a mdupree��csir.co.�a
South African Journal of Science, 2013
Impact of solar irradiation on cholera toxin secretion by different strains of Vibrio cholerae Ch... more Impact of solar irradiation on cholera toxin secretion by different strains of Vibrio cholerae Cholera toxin is the aetiological agent of cholera-a deadly waterborne disease acquired through the consumption of untreated water contaminated with CTXФ bacteriophage harbouring strains of V. cholerae. Solar disinfection is a re-emerging technique that relies on the ultraviolet component of sunlight to inactivate the growth of Vibrio cholerae in water, rendering the water microbiologically safe for consumption. However, studies have shown that DNA damaging agents, such as ultraviolet light, induce the replication of the CTXФ bacteriophage with subsequent expression of the cholera toxin. In this study we investigated the impact of solar irradiation on the secretion of cholera toxin by toxigenic strains of V. cholerae in water. The cholera toxin ELISA assay, qualitative and quantitative real-time PCR as well as growth on solid media were used to determine cholera toxin secretion, DNA integrity and growth of the bacteria after 7 h and 31 h of solar irradiation. Solar irradiation in water reduced the integrity of DNA, inactivated the growth of V. cholerae and, most importantly, prevented the secretion of detectable levels of cholera toxin. This finding is encouraging for resource-poor communities that may rely on solar disinfection to alleviate the burden of cholerarelated fatalities. In this study we investigated the potential for sunlight to induce the secretion of cholera toxin by toxigenic strains of V. cholerae by means of solar irradiating the microorganisms in water. Material and methods Vibrio cholerae strains and culture conditions Seven strains of V. cholerae-six toxigenic and one non-toxigenic-were used in this study: NCTC 5941 and NCTC 12945 obtained from the national collection of type cultures; BRITS01 isolated from Brits, South Africa; G4222
Rural households are o�ten dependent on rivers, springs, boreholes or standpipes some distance �r... more Rural households are o�ten dependent on rivers, springs, boreholes or standpipes some distance �rom their homes �or their daily water requirements. Water �or drinking and domestic use is consequently stored in containers in�house which are prone to post�collection contamination. The objective o� the study was to determine the most likely origin or place o� introduction o� E. coli associated with post�collection contamination in rural households, by assessing the degree o� genetic relatedness o� E. coli present in the stored water and other environmental samples. E. coli isolates were obtained using either mFC agar with confirmation of indole production (44 isolates) or Colilert ® -18 (52 isolates). Amplified fragment length polymorphism (AFLP) fingerprinting was applied to determine the genetic relatedness of E. coli isolated �rom in�house storage containers, drink� ing cups, hand-swab samples, cattle dung and from the source water (spring water). DNA fingerprints of E. coli produce...