title: Occurrence of diarrhoeagenic Escherichia coli virulence genes in water and bed sediments of a river used by communities in Gauteng, South Africa.
abstract: In most developing countries, especially in Southern Africa, little is known about the presence of diarrhoeagenic Escherichia coli (DEC) pathotypes in riverbed sediments. The present study sought to investigate the presence of DEC virulence genes in riverbed sediments of the Apies River, a river used by many communities in Gauteng, South Africa. Water and sediment samples were collected from the river between July and August 2013 (dry season) and also between January and February 2014 (wet season) following standard procedures. Isolation of E. coli was done using the Colilert®-18 Quanti-Tray® 2000 system. DNA was extracted from E. coli isolates using the InstaGene™ matrix from Bio-Rad and used as template DNA for real-time PCR. Water pH, temperature, dissolved oxygen, electrical conductivity and turbidity were measured in situ. Over 59 % of 180 samples analysed were positive for at least one of the seven DEC virulence genes investigated. The eaeA gene was the most isolated gene (29.44 %) while the ipaH gene the least isolated (8.33 %). The ipaH gene (p = 0.012) and the ST gene (stIa, p = 0.0001, and stIb, p = 0.019) were positively correlated with temperature. The detection of diarrhoeagenic E. coli virulence genes in the sediments of the Apies River shows that the sediments of this river might not only be a reservoir of faecal indicator bacteria like E. coli but also pathogenic strains of this bacterium. These organisms could represent a public health risk for poor communities relying on this water source for various purposes such as drinking and recreational use. There is therefore an urgent need to monitor these DEC pathotypes especially in areas without adequate water supplies.
authors.affiliation: Department of Environmental, Water and Earth Science, Tshwane University of Technology, Arcadia Campus, 175 Nelson Mandela Drive, Private Bag X 680, Pretoria, 0001, South Africa.
authors.forename: Akebe Luther King
authors.initials: AL
authors.lastname: Abia
authors.affiliation: Natural Resources and the Environment, CSIR, PO Box 395, Pretoria, 0001, South Africa. eubombajaswa@csir.co.za.
authors.forename: Eunice
authors.initials: E
authors.lastname: Ubomba-Jaswa
authors.affiliation: Department of Environmental, Water and Earth Science, Tshwane University of Technology, Arcadia Campus, 175 Nelson Mandela Drive, Private Bag X 680, Pretoria, 0001, South Africa. mombamnb@tut.ac.za.
authors.forename: Maggy Ndombo Benteke
authors.initials: MN
authors.lastname: Momba
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics*; D019015:Geologic Sediments / Q000382:microbiology*; D045483:Rivers / Q000382:microbiology*; D012621:Seasons; D013019:South Africa; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*; D014867:Water
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors; D014867:Water
keywords: Diarrhoeagenic E. coli (DEC); Environmental monitoring; Public health risk; Riverbed sediments; Rural communities; Virulence genes; Water quality