comparison of microbial quality assessment of water sources using multiple tube fermentation technique and enzymatic assay

background : microbial monitoring of aquatic sources is essential in the correct management of these vital sources. multiple tube fermentation (mtf) technique is currently used for assessment of the microbial quality of water sources. however, today enzymatic assay has been presented as an alternative approach for detecting indicator bacteria. the purpose of this study was to compare enzymatic assay with mtf technique in terms of the detection of total and fecal coliforms in potable and non-potable waters. methods: a total of 64 samples were collected from different water sources (potable, spring, well, and aqueduct water, and wastewater effluent). detection of total and fecal (escherichia coli) coliforms was performed using mtf method and enzymatic assay using lmx broth. the relationship between the parameters measured by the two methods was tested using the pearson correlation. the sensitivity, specificity, and accuracy of enzymatic assay were also evaluated. findings: statistical analysis of results showed a high correlation between total and fecal coliform measurements by the two methods. enzymatic assay had a sensitivity, specificity, and accuracy of 92, 95, and 94 percent, respectively. conclusion: due to the advantages of enzymatic assay, such as its relatively high sensitivity, accuracy, and speed, and simultaneous detection of total coliforms and e. coli, enzymatic assay using lmx can be used as an alternative method to mtf.