Canadian Society for Medical Laboratory Science (CSMLS) Practice Exam

What is the optimum temperature for growth of most human pathogens?

1. 25°C

2. 37°C

3. 30°C

4. 45°C

The correct answer is: 37°C

The optimum temperature for the growth of most human pathogens is indeed 37°C. This temperature closely aligns with the normal body temperature of humans, providing an ideal environment for bacterial growth and replication. Most human pathogens, including bacteria like Escherichia coli and Staphylococcus aureus, thrive at this temperature because it allows for optimal enzyme activity and metabolic processes that are essential for their survival and proliferation in the human host. At temperatures significantly lower than this, such as 25°C or 30°C, the metabolic and reproductive processes of these pathogens may slow down, leading to suboptimal growth. Additionally, a temperature as high as 45°C can be detrimental to human pathogens, as it exceeds the thermal tolerance of most of these organisms, often leading to cell damage or death. Understanding this temperature preference is crucial for laboratory settings, as it guides the incubation conditions used for culturing pathogens and can help in the identification and characterization of infectious agents.