Which of the following is NOT true of staphylococci?

• A. Most strains make us very ill.
• B. They are bacteria.
• C. They can cause skin infections.
• D. They are Gram-positive cocci.

Answer: (A)

Staphylococci are bacteria that appear as Gram-positive cocci in grape-like clusters. They’re a common part of the skin’s normal flora, so most strains do not cause illness in healthy people. Only certain strains, such as Staphylococcus aureus, can cause skin infections or more serious disease, while many others (coagulase-negative staphylococci) are largely harmless. Therefore, the statement that most strains make us very ill is not true. The other points—that they’re bacteria, they can cause skin infections, and they are Gram-positive cocci—are correct.