Harr Microbiology Practice Test 2026 – 400 Free Practice Questions to Pass the Exam

Prereduced peptone-yeast extract-glucose (PYG) broth is specifically formulated to cultivate anaerobic bacteria and promote the detection of volatile fatty acids. The composition of PYG broth provides not only the necessary nutrients for the growth of anaerobes but also creates an environment that minimizes the presence of oxygen, which is crucial for the growth of these bacteria. This is particularly important since anaerobic bacteria thrive in low-oxygen conditions and are often sensitive to the presence of oxygen, which can inhibit their growth or even kill them.

In addition to being a non-oxidizing medium, PYG broth contains components that encourage the production of metabolic byproducts, such as volatile fatty acids, which can be critical for certain diagnostic and research applications. Its formulation allows for robust growth and metabolic activity that can be easily analyzed for these specific metabolites.

Other broths mentioned may support the growth of various types of bacteria but do not specifically cater to anaerobic bacteria in the same efficient manner as PYG broth does. For instance, THIO broth is designed for both aerobic and anaerobic bacteria but is not as specialized for detecting volatile fatty acids. Meanwhile, Gram-negative (GN) broth and Selenite (SEL) broth are primarily utilized for the