Question

How are api strips inoculated with a bacterium interpreted?

a) strips with positive reactions for each test indicate a bacterium is gram negative.
b) strips with positive reactions for each test indicate a bacterium is gram positive.
c) lab personnel interpret strips by using a dichotomous key and beginning with a key reaction.
d) lab personnel interpret strips by determining the ph of each individual well.

Answer 1

Lab personnel use API test strips and interpret reactions using a database to identify specific bacteria, with a dichotomous key beginning with key reactions, not just by determining whether a bacterium is Gram-negative or Gram-positive.

Step-by-step explanation:

API strips are inoculated with bacteria to determine the specific type of bacterium. API test panels contain multiple biochemical tests that can identify over 600 species of bacteria and 100 types of yeasts. When inoculated, these test strips contain a variety of substrates and pH indicators that show color changes depending on the metabolic reactions of the bacteria. Lab personnel then compare these color changes to a database profile to identify the microorganism. The correct answer to the student's question is that lab personnel interpret strips by using a dichotomous key and beginning with a key reaction (Option C). Gram staining is usually the first step in identifying whether a bacterium is Gram-positive or Gram-negative before using biochemical tests like those in API strips to further differentiate and identify the bacterial species.