Which of the following correctly describes the typical sequence of events that leads to a healthcare-associated infection (HAI)?

• A. Source of microorganisms → Mode of transmission → Susceptible host
• B. Susceptible host → Mode of transmission → Source of microorganisms
• C. Susceptible host → Source of microorganisms → Mode of transmission
• D. Mode of transmission → Susceptible host → Source of microorganisms

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the concept of healthcare-associated infections (HAIs), which occur when microorganisms from a source infect a susceptible host through a specific mode of transmission.
2. Step 2: Identify the three key components involved in the chain of infection: the source of microorganisms (reservoir), the mode of transmission (how the microorganisms spread), and the susceptible host (the person at risk of infection).
3. Step 3: Recognize that the typical sequence starts with the source of microorganisms, as this is where the infectious agents originate.
4. Step 4: Next, the microorganisms must be transmitted from the source to the host, so the mode of transmission comes after the source.
5. Step 5: Finally, the susceptible host is the individual who becomes infected after exposure to the microorganisms via the mode of transmission, completing the sequence: Source of microorganisms → Mode of transmission → Susceptible host.