Compatibility Rate of Three Laboratory Methods for Enumerating Thermo-tolerant Coliforms in Water Resources

Document Type : Technical Note


1 Assoc. Prof., Dept. of Environmental Health, Kermanshah University of Medical Sciences

2 Assist. Prof. of Biostatics of KUMS, Kermanshah University of Medical Sciences

3 Laboratory Expert, Kermanshah University of Medical Sciences


It is essential to evaluate the methods applied in the detection and enumeration of bacterial indices used in water quality management. The present study (descriptive and analytical in nature) aimed to determine the correlation and compatibility rates of the detection methods of multiple tube fermentation (both traditional and direct techniques) using EC Broth and plate count in special fecal coliform culture media. The objective was to identify the one method among these which is economical, effective, rapid, and easy to use under emergency conditions. Pour plate count using eosin-methylen blue (EMB) was evaluated in comparison with the traditional and direct multiple tub fermentation (MTF) as techniques used in enumerating thermo-tolerant bacteria and Escherichia coli in water resources.. 14 samples were required for the pilot study. However, 70 samples were analyzed to obtain a higher level of accuracy through three microbial laboratory methods. In evaluating raw water collected from wells, springs, and rivers as well as the effluent from wastewater treatment plants, a high Pearson correlation was found for enumerating thermo-tolerant bacteria. The results revealed that the majority of the samples contained thermo- tolerant coliforms. Based on the correlation coefficients calculated among the three methods, economic considerations, test duration, and time to yield results the plate count, the direct MTF, and the traditional MTF may be ranked in a descending priority order from the viewpoint of bacterial quality assessment of water resources for the emergency conditions and irrigation purposes


1- Eccles, J. P., Searle, R., Holt, D., and Denniis, P. J. (2004). “A comparison of methods used to enumerate Escherichia coli in conventionally treated sewage sludge.” J. of Applied Microbiology, 96 (2),  375-383.
2- World Health Organization. (1993). Guidelines for drinking water quality, 2nd Ed.,Volume (1-3).
3- Chihara, R.J., Sullivan, M. A., Likirdopulos, C.A., Simmons, O.D., Burch, C. L., and Sobsey, M. D. (2005). Comparison of methods for detection of fecal coliforms and Escherichia coli in agricultural and municipal wastewater systems, Animal waste management symposium, Department of Environmental Sciences and Engineering, The university of North Carolina at Chapel Hill, School of Public Health.
4- Board-Andrew, D. E., Lenore, S., and Clesceri, Arnold, E. (1998). “Greenberg standard methods for the examination of water and wastewater.” American Public Health ASSO Ciation, 9-57.
5- Alonso, J. L., Soriano, A., Carbajo, O., Amoros, I., and Garelick H. (1999). “Comparison and recovery of Escherichia coli and thrmotolerant coliforms in water with a chromogenic medium incubated at 41 and 44.5 0C.” Appl. Environ. Microbiol, 65 (8), 3746-3749.
6- Richards, G.P. (1978). “Comparative study of methods for the enumeration of total and faecal coliforms in the estern Oysite;Grostrea Virginica.” Appl. Environ. Microbiol., 36(6), 975-978.
7- Bredie, W. L., and deBoer, E. (1992). “Evaluation of the MPN, Anderson-Baird-Parker, petrifilm E.Coli and fluorocult ECD method for enumeration of Escherichia coli in foods of animal origin.” Int J. food Microbiol, 16 (3), 197-208.
8- Ononu, Y., Konuma H., Nakagava, K., Fujita, T., and Kumagai, S. (1999). “Collaborative evaluation of detection methods for Escherichia coli O 157: H7 From radish sprouts and ground beef.” Int. J. Food Microbiol., 46 (1), 27-36.
9- Filius, P.M.G., Van Netten, D., Roovers, P. J. E., Vulto, A.G., Gyssens, I.C., and et al. (2003). “Comparative evaluation of three chromogenic agars for detection and rapid identification of aerobic gram negative baeteria in the normal intestinal microflora.” Clinical Microbiology and in Fection, 9 (9), 912-918.
10- Bwciebin , M., Brodsky, H., Eddington, R., and et al. (1995). “Comparative evaluation of modified m – FE and m-TEC media for membrane  filter enumeration of Escherichia coli in water.” Appl. Environ. Microbiol., 61(11), 3940-3942.
11- Reasoner, D.J., Blannon, J.C., and Geldeneh, E.E. (1979). “Rapid seven hour fecal coliform Test.” APP. Environ. Microliol, 38 (2), 229- 236.
12- Bitton, G. (1999). Wastewater microbiology, Willy-Liss, Canada.
13- Lucica, M., Tamagnini, R., and Gonzảlez, D. (2001). “Evaluation of two media and different plating techniques for enumeration of thermotolerant coliforms in river water.” Rev. Latinoam. Microbiol., 43(2), 84-87.
14- Anon. (2000a). Comparison of methods for drinking water bacteriology cultural techniques, Drinking water inspectorate information, UK Drinking Water Inspectorate, England.
15- Anon. (2000b). ISO 9308-1: Water quality- Detection and enumeration of Eschericia coli and total coliformnbacteria, Genevan Switzerland, International Organization for Standardization.
16- Schets, FM., Nobel, P. J., Strating, S., and et al. (2002). “Europian drinking water directive reference methods for enumeration of total  coliform and escherichia coli compared with alternative methods.” Appli. Microbiology, 34, 227-231.