Direct MPN for faecal coliform

Area of Science:

• Environmental microbiology
• Water quality analysis
• Bacteriology

Background:

• Assessing microbial contamination in water sources like the Nile and Ismailia canals is crucial for public health.
• Standard methods for detecting indicator bacteria, such as E. coli, require efficient and reliable techniques.

Purpose of the Study:

• To evaluate the efficacy of different culture media and techniques for detecting E. coli in canal water.
• To determine the prevalence and types of E. coli in the Nile and Ismailia canal water samples.

Main Methods:

• Water samples from the Nile and Ismailia canals were analyzed using direct inoculation and incubation at elevated temperatures.
• MacConkey broth and EC broth media were compared for bacterial growth.
• The Direct Most Probable Number (MPN) technique was employed for quantification.
• Isolates were identified using IMViC (Indole, Methyl red, Voges-Proskauer, Citrate) tests and the Eijkman test.

Main Results:

• MacConkey broth medium demonstrated superior performance compared to EC broth.
• The Direct MPN technique proved suitable and effective, identifying E. coli in 90% of the examined samples.
• A total of 300 isolates were recovered, with 96% identified as E. coli proper and 4% as irregular types.

Conclusions:

• The Direct MPN technique combined with MacConkey broth is a highly effective method for detecting E. coli in canal water.
• The study highlights the significant presence of E. coli in the studied canal water, emphasizing potential public health risks.
• Further investigation into the characteristics of irregular E. coli types may be warranted.