Reference no: EM132710982

1. The goal of this bacteriological examination of water is to detect the presence of fecal coliform bacteria.

a. List four characteristics of coliform bacteria

b. Why the water source is considered "unsafe" if there is the presence of fecal coliform in the water.

2. The Presumptive Test: Here is the result of the Presumptive Test (Positive tube = acid/gas reaction)

a. Find the MPN index by using the following presumptive test result and the MPN and 9% Confidence Limits table provided in the lab manuals

b. Explain the meaning of the MPN Index

3. The Confirmed Test: From any positive tube with highest dilution sample and showing 10% gas production or more, streak a full loop of the broth onto Endo agar and onto the EMB agar.

a. Describe the results shown in the Endo medium and in the EMB medium

b. What conclusion can you make based on the result of the confirmed test? Endo agar

4. The Completed Test is to reaffirm gas production in lactose, and to determine the morphology and gram reaction of the isolate from a nutrient agar slant. Assuming you perform the Gram staining. Sketch and describe the morphology of that bacterium under the microscope.