Which term best describes bacteria that do not produce disease under normal conditions?

• A. Pathogenic
• B. Nonpathogenic
• C. Opportunistic
• D. Virulent

Answer: (B)

Bacteria that do not produce disease in a healthy person are described as nonpathogenic. This term signals that, under normal conditions, these organisms do not cause illness and are often harmless residents of our bodies or the environment.

To place it in context, pathogenic bacteria are capable of causing disease, with virulence referring to how strong their disease-causing ability is. Opportunistic pathogens are those that typically only cause disease when the host’s defenses are weakened or when they enter parts of the body they don’t normally inhabit. So, while nonpathogenic bacteria are not disease-causing in a typical healthy host, they can still pose a risk if the host is compromised.