The wastes , particularly human wastes , are the main cause of microbial diseases , which is a threat to human and animal health. The application of wastewater without treatment leads to agricultural soil contamination . In this study, seven bacterial isolates of colon bacteria Escherichia coli were obtained from Aden wastewate r plants. During isolation, several selective media such as macconkey­ agar , Endo-agar, Kligler-iron agar were used. Morphological and biochemical tests, apart from pathogenic tests, using potato slices were carried out to determine characteristics of these bacteria. Results of these tests showed that all isolates belong to colon bacteria Escherichia coli.

Key Words :Colon bacteria, Laboratorv methods, Wastewater , Aden, Yemen.