Cutibacterium (formerly Propionibacterium) bacteria, computer illustration. These are an example of non-pathogenic bacteria found on human skin, where they are well adapted to the natural acidity. An example is Cutibacterium acnes, found in the hair follicles and pores of the skin, where it usually causes no problems. However, if there is an overproduction of sebum (sebaceous oil), the bacteria proliferate, producing enzymes that damage the skin and cause acne.