Nonpathogenic bacteria are bacteria that ...

• A. Do not cause disease
• B. Cause disease
• C. Are viruses
• D. Are fungi

Answer: (A)

Nonpathogenic describes bacteria that do not cause disease in a healthy person. They are part of the normal microbial community and can even aid health in various ways, since they lack the virulence traits that would make them disease-causing under ordinary conditions. It’s important to remember that viruses and fungi are different kinds of organisms, so a nonpathogenic bacterium is not a virus or a fungus. In rare cases, even nonpathogenic bacteria can cause problems if they enter sterile parts of the body or if the immune system is compromised, but the usual meaning is that they do not cause disease.