What must be present in every bacterial infection?

Pathogenic bacteria must be present in every bacterial infection because they are the microorganisms responsible for causing the infection. Bacteria that are classified as pathogenic have the ability to invade host tissues, multiply, and produce toxins or other substances that can lead to disease. In the context of a bacterial infection, the presence of these bacteria is essential, as they directly trigger the immune response and the symptoms associated with the infection.

While antibodies are the body’s response to an infection, they do not exist until the immune system recognizes and responds to the presence of pathogens. Similarly, viruses are a different class of infectious agents and are not part of a bacterial infection. Enzymes can play various roles within bacteria, but they are not a requirement for the presence of an infection itself. Their presence or activity might assist in the pathogenic processes, but the fundamental requirement for defining a bacterial infection rests solely on the existence of pathogenic bacteria.