The Characteristics of Escherichia coli Isolated from Water and Feces in Khartoum State as Indicator of Fecal Contamination

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Date
2007
Authors
Safa Abbas Mohammed Abdelrahman Sherfi
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Publisher
University of Khartoum
Abstract
In this study ninety four isolates of E. coli were obtained from different sources of water, sewage, and human and animal feces by using multiple tube fermentation technique or by direct streaking on MacConkey agar. All isolates were first identified biochemically using a Japanese API like system. Then the E. coli isolates were subjected to molecular biology finger- printing identification technique, using Polymerase Chain Reaction (PCR). The results of these tests indicated that the PCR could be used as an alternative or supportive diagnostic assay to the conventional bacteriological identification procedure. The physiological characteristics of the E. coli isolates were examined by studying their growth in different culture media, i.e., E. coli medium (EC), brilliant green bile broth (BGB), MacConkey broth, and lauryl sulphate tryptose broth, at different temperatures, viz., 30, 37 and 44.5°C. The results of these tests showed that EC broth medium yielded the highest growth density of E. coli at all temperatures. Brilliant green bile broth gave the next best growth density, followed by MacConkey broth, then lauryl sulphate tryptose broth. The incubation Temperature 37°C gave the highest growth density in all four growth media, the lowest growth density being obtained at 44.5°C. The survival of E. coli isolates in sterile tap water was studied. The count of E. coli isolates per ml decreased gradually starting on the sixth day of incubation at ambient temperature to reach the count less than two on day 18. The results of this study indicated that E. coli can be used as a fecal indicator in water in Sudan but the choice of media used as well as the survival of the organism in pure water should be taken into consideration.
Description
Ph.D Thesis in Environmental Microbiology
Keywords
Environmental Microbiology Fecal Contamination University of Khartoum Botany Agricultural Biotechnology
Citation
Safa Abbas Mohammed Abdelrahman Sherfi, The Characteristics of Escherichia coli Isolated from Water and Feces in Khartoum State as Indicator of Fecal Contamination .- Khartoum : University of Khartoum, 2007 .- 165p. : illus., 28cm., Ph.D