Suitability of total coliform a-d-galactosidase activity and CFU counts in monitoring faecal contamination of environmental water samples

Total coliforms are a group of bacteria found in high numbers in mammalian intestines; hence their presence in water indicates the possible contamination with faecal material. Total and faecal coliform counts were monitored over a period of 18 months using mFC, m-Endo and CM1046 media together with enzymatic assays on 215 environmental water samples obtained from the Eastern Cape Province of South Africa. A positive correlation, with an R2 value of 0.9393 was observed between faecal and total coliform colony units employing mFc and m-Endo media, and 0.8818 using CM1046 media. Also, a positive correlation was observed between Escherichia coli colony-forming units and a-d-galactosidase (B-GAL) activity (R2=0.8542). Overall, this study indicated that faecal contamination of environmental water samples could be monitored by measuring total coliform a-galactosidase activity and total coliform colony-forming units.