Enterotoxins as a molecular marker of water quality

Abstract Safety of improved water supplies using enterotoxins as a molecular marker is evaluated. Water samples were collected from 248 households and tested for enterotoxins using polymerase chain reaction (PCR). The relationships between the presence of at least one enterotoxin and independent variables were investigated using Chi-square (χ2), Fisher's exact test and binary logistic regression. Some 156 enterotoxin biomarkers were detected, 39% of samples had at least one, and 17% had multiple varieties. EAST1 was detected in the highest proportion of samples (33%) and Sta in the lowest (2%). Shallow groundwater sources yielded 18% less enterotoxins than water from piped systems, a statistically significant result (P=0.031). A lower proportion of enterotoxins was detected in relation to those who did not know and use cloth filters than those with knowledge of them, and the negative association is statistically significant (P=0.017). It was shown that water samples in which total coliform (TC) colonies were detected were more likely to contain enterotoxins than those without (P=0.001). It is concluded that enterotoxin molecular markers can be used to monitor water safety.