A scientist engineered a Gram-positive bacterium to express a polysaccharide-rich outer capsule. What effect would this have on a Gram stain of this engineered organism? Explain your answer in one sentence.

HLTH-320 Introduction to Infectious Disease

LAB QUIZ 2

1. (9 points) A scientist engineered a Gram-positive bacterium to express a polysaccharide-rich outer capsule. What effect would this have on a Gram stain of this engineered organism? Explain your answer in one sentence.

2. (9 points) A scientist engineered a strain of S. aureus so that it no longer produced protein A. What effect would this have on a StaphTEX test of this engineered organism? Explain your answer in one sentence.

3. (9 points) Suppose you performed a Gram stain on a culture of Klebsiella pneumoniae but you accidentally skipped the decolorizer step. What color would the cell appear under the microscope?

4. (9 points) Suppose you performed a Gram stain on a culture of S. aureus but you accidentally skipped the Gram’s iodine step. What color would the cell appear under the microscope?

5. (4 points) What is the difference between Klebsiella pneumoniae and Klebsiella pneumonia?