Bacteria get a “bad wrap” due to the many diseases that are caused by bacteria. Help improve bacteria’s reput

Bacteria get a “bad wrap” due to the many diseases that are caused by bacteria. Help improve bacteria’s reputation by identifying a beneficial bacterium. Provide the name of the bacterium (use genus and species names, such as Staphylococcus aureus), the beneficial function of the bacterium and the source of your information

It's true, many bacteria are pathogen or opportunistic pathogens (usually won't cause disease but if your immune system is compromised, can potentially). However many bacteria such as the flora in our digestive systems are in a symbiotic relationship with us humans so without each other, we'd perish. I'm not going to list their classifications as you can do that on your own (start with the link in the source box--it's pretty creditable and informative).
We also eat many foods that contain "good" bacteria such a Bifadius Regularis and Bifidus Actiregularis that Dannon produces.