The Study on the Survival of Escherichia Coli in Water at Room Temperature

Abstract

Escherichia coli (E. coli) is one of the most frequent causes of many bacterial infections especially gastroenteritis in developing countries. It is also used as an indicator for faecal pollution in the surveillance of bacteriological quality of drinking water. This study was conducted to determine the survival of E. coli in water at room temperature (27oC). E. coli which is cultured in Lactose Peptone Broth was inoculated into 8 bottles each containing 10 millilitres of distilled water. They were kept at 27oC. Starting from the day 1, ten-fold dilutions were made from each bottle number and E. coli count was done from each dilutions by using pour plate method. The colony forming unit/ millilitre (CFU/ml) was calculated. The same procedure was carried out from bottles number 2 to 8 from day 2 to day 8 consecutively. CFU/ml of E. coli in dilution 10-5was markedly decreased from 3.9 x 106 in day 1to 0 in day 8. The findings suggest that if the water is contaminated with low number of E. coli, it can be eliminated by keeping water at room temperature for only few days.