Certified Surgical Technologist (CST) Practice Exam

Which microbes live without oxygen?

1. Capnophiles

2. Microaerophiles

3. Anaerobes

4. Aerobes

The correct answer is: Anaerobes

Anaerobes are microbes that thrive in environments devoid of oxygen. They have adapted to utilize other processes, such as fermentation or anaerobic respiration, to generate energy. This allows them to live and grow in conditions that would be toxic to aerobic organisms, which require oxygen for their survival and metabolic processes. Understanding anaerobes is crucial, particularly in surgical settings where maintaining sterile environments is essential. The overgrowth of anaerobic bacteria can lead to infections, especially in deep wounds where oxygen is scarce. Examples of anaerobic bacteria include Clostridium species, which can cause severe infections such as tetanus and gas gangrene. Capnophiles, while they do require carbon dioxide for growth, still depend on some level of oxygen. Microaerophiles require low levels of oxygen and cannot survive in atmospheric concentrations, whereas aerobes need oxygen to grow and thrive. Each of these categories denotes specific oxygen requirements that distinguish them from anaerobes.