title: Genetic relatedness of faecal coliforms and enterococci bacteria isolated from water and sediments of the Apies River, Gauteng, South Africa.
abstract: To date, the microbiological quality of river sediments and its impact on water resources are not included in the water quality monitoring assessment. Therefore, the aim of this study was to establish genetic relatedness between faecal coliforms and enterococci isolated from the river water and riverbed sediments of Apies River to better understand the genetic similarity of microorganisms between the sediment and water phases. Indicator bacteria were subjected to a molecular study, which consisted of PCR amplification and sequence analysis of the 16S rRNA and 23S rRNA gene using specific primers for faecal coliforms and enterococci, respectively. Results revealed that the Apies River had high faecal pollution levels with enterococci showing low to moderate correlation coefficient (r2values ranged from 0.2605 to 0.7499) compared to the faecal coliforms which showed zero to low correlation (r2values ranged from 0.0027 to 0.1407) indicating that enterococci may be better indicator than faecal coliforms for detecting faecal contamination in riverbed sediments. The phylogenetic tree of faecal coliforms revealed a 98% homology among their nucleotide sequences confirming the close genetic relatedness between river water and riverbed sediment isolates. The phylogenetic tree of the enterococci showed that Enterococcus faecalis and Enterococcus faecium are the predominant species found in both river water and riverbed sediments with bootstrap values of ≥99%. A high degree of genetic relatedness between sediment and water isolates indicated a possible common ancestry and transmission pathway. We recommend the microbial monitoring of riverbed sediments as it harbours more diverse microbial community and once resuspended may cause health and environmental problems.
authors.affiliation: Department of Environmental, Water and Earth Sciences, Tshwane University of Technology, Arcadia Campus, Private BagX680, Pretoria, 0001, South Africa. ekwanzalamd@tut.ac.za.
authors.forename: Mutshiene Deogratias
authors.initials: MD
authors.lastname: Ekwanzala
authors.affiliation: Department of Environmental, Water and Earth Sciences, Tshwane University of Technology, Arcadia Campus, Private BagX680, Pretoria, 0001, South Africa.
authors.forename: Akebe Luther King
authors.initials: ALK
authors.lastname: Abia
authors.affiliation: Natural Resources and the Environment, CSIR, PO Box 395, Pretoria, 0001, South Africa.
authors.forename: Eunice
authors.initials: E
authors.lastname: Ubomba-Jaswa
authors.affiliation: Department of Environmental, Water and Earth Sciences, Tshwane University of Technology, Arcadia Campus, Private BagX680, Pretoria, 0001, South Africa.
authors.forename: Jitendra
authors.initials: J
authors.lastname: Keshri
authors.affiliation: Department of Environmental, Water and Earth Sciences, Tshwane University of Technology, Arcadia Campus, Private BagX680, Pretoria, 0001, South Africa. mombamnb@tut.ac.za.
authors.forename: Ndombo Benteke Maggy
authors.initials: NBM
authors.lastname: Momba
keywords: Enterococcus spp; Faecal coliforms; Genetic similarity; River water; Riverbed sediment