Do most bacteria cause disease? Explain.

No, most bacteria do not cause disease. In fact, many bacteria are harmless or beneficial to humans and other organisms. For example, the human microbiome consists of billions of bacteria that aid in digestion, produce vitamins, and help protect against harmful pathogens. Disease-causing bacteria, or pathogenic bacteria, make up a small fraction of bacterial species and usually cause illness only when they produce toxins or invade tissues. The presence of virulence factors, such as toxins or the ability to evade the immune system, is what enables certain bacteria to cause disease.