Occupational Safety and Health Administration (OSHA) SLC Practice Exam

What type of infection is caused by microorganisms already present in the human body?

1. Exogenous infection

2. Endogenous infection

3. Contagious infection

4. Opportunistic infection

The correct answer is: Endogenous infection

Endogenous infections occur when microorganisms that are already present in the human body, such as bacteria, fungi, or viruses, cause disease. This can happen when the balance of these microorganisms is disrupted, leading to opportunistic growth or when the immune system is compromised. The body's own flora, which normally coexist without causing harm, may become pathogenic due to various factors such as illness, stress, or antibiotic use, allowing them to proliferate and lead to an infection. In contrast, exogenous infections arise from pathogens that enter the body from an external source, such as through the environment, other individuals, or contaminated objects. Contagious infections are a subset of exogenous infections that can be easily transmitted from person to person. Opportunistic infections typically occur in individuals with weakened immune systems and can be caused by endogenous or exogenous microorganisms, but the defining feature is the compromise of the host's defenses rather than the origin of the pathogens.