Microbiology And Immunology 6400 Oral Intermicrobial Interactions Practice Test

Hydrogen peroxide production in the oral microbiome is not a universal trait; only a subset of bacteria have this capability. In certain oral streptococci, hydrogen peroxide is produced as a byproduct of metabolism via the enzyme SpxB, a pyruvate oxidase. This enzyme uses pyruvate, inorganic phosphate, and oxygen to generate acetyl phosphate, carbon dioxide, and hydrogen peroxide. Ecologically, the H2O2 acts as an antimicrobial weapon that helps these bacteria compete and shape the biofilm environment. Veillonella and many other oral bacteria don’t rely on this pathway, so they don’t produce hydrogen peroxide through SpxB. Therefore, describing hydrogen peroxide production as coming from some oral bacteria via SpxB captures both the selectivity and the enzymatic basis of this trait.