Which type of microorganisms are associated with causing diseases, as described?

• A. Prokaryotes
• B. Pathogenic microorganisms
• C. Nonpathogenic microorganisms
• D. Bacteria only

Answer: (B)

Pathogenic microorganisms are those that have the ability to cause disease in a host. They can be bacteria, viruses, fungi, or parasites, and they’re the type you focus on in infection control because they’re capable of initiating illness if not handled properly. By contrast, nonpathogenic microorganisms don’t cause disease, and prokaryotes describe a broad category of cellular life (including many bacteria) that can be either harmless or disease-causing, so that term isn’t specific to disease. Bacteria-only is too narrow because many diseases are caused by other types of pathogens, such as viruses and fungi, not just bacteria.