Eosin Methylene Blue Agar (EMB) Is a Selective and Differential

question 41

Multiple Choice

Eosin methylene blue agar (EMB) is a selective and differential medium. The dyes in the medium inhibit most Gram-positive organisms. Gram-negative organisms such as the coliforms grow on this medium. Coliforms that are fecal in origin produce colonies with a metallic green color on EMB, while those that are non-fecal produce colorless colonies. You plate a urine sample onto an EMB plate and incubate it. Metallic green colonies develop. From this, you can conclude that 

• A) the sample contains bacteria that are Gram-negative AND are non-fecal in origin.
• B) the sample contains bacteria that are Gram-negative AND are fecal in origin.
• C) the sample contains bacteria that are Gram-positive AND are fecal in origin.
• D) the bacteria in the colonies are Gram-positive AND are rod-shaped.
• E) normal microbiota in the bladder is fecal in origin AND is aerobic.

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Definitions:

T Value

A value computed from a sample data used in a t-test in statistics that measures the size of the difference relative to the variation in your sample data.

Confidence Interval

A swath of numerical values, from statistics of a sample, aimed at covering the unascertained value of a population parameter.

Margin of Error

The half-width of a confidence interval, representing the maximum expected difference between the true population parameter and a sample estimate of that parameter.

Population Standard Deviation

A measure of the dispersion or spread of a set of data values in a population, indicating how much individuals within this population vary from the population mean.