Questions: A clinician orders a gram stain test that reveals gram-positive organisms. Which of the following organisms may be in the sample? Select all that apply. Streptococcus pneumoniae Staphylococcus aureus Streptococcus pyogenes Escherichia coli Shigella

The organisms that may be in the sample are:

• Streptococcus pneumoniae
• Staphylococcus aureus
• Streptococcus pyogenes

Explanation:

1. Streptococcus pneumoniae: This is a gram-positive bacterium. It appears as lancet-shaped diplococci under the microscope.
2. Staphylococcus aureus: This is a gram-positive bacterium. It appears as clusters of cocci under the microscope.
3. Streptococcus pyogenes: This is a gram-positive bacterium. It appears as chains of cocci under the microscope.

The following organisms are not gram-positive: 4. Escherichia coli: This is a gram-negative bacterium. 5. Shigella: This is a gram-negative bacterium.

Summary: The organisms that may be in the sample are Streptococcus pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes.