Which type of bacteria are responsible for causing diseases?

Pathogens are the type of bacteria specifically responsible for causing diseases in humans, animals, and plants. These microorganisms have various mechanisms that enable them to invade host tissues, evade the immune system, and produce toxins, ultimately leading to illness. Pathogens can be further classified into different groups, such as bacteria, viruses, fungi, and parasites, but in the context of this question, the focus is specifically on pathogenic bacteria.

Other types of bacteria play different roles in relation to health. Commensals, for instance, are bacteria that typically coexist with humans without causing harm and can even provide beneficial functions such as aiding in digestion. Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit to the host, often enhancing gut health and immune function. Non-pathogenic organisms are those that do not cause disease and can often be found in environments that are otherwise healthy. Understanding these distinctions is crucial in the field of healthcare and sterile processing, as it influences infection control practices and the management of sterile environments.