Acne bacteria, specifically Propionibacterium acnes, thrives on sebum, which is the oily substance produced by the sebaceous glands in the skin. The bacteria feed on the excess sebum, dead skin cells, and other debris that can clog pores, leading to the formation of acne lesions. The overgrowth of these bacteria can contribute to the inflammation and formation of pimples. Factors such as hormonal changes, genetics, diet, stress, and certain medications can also influence acne development.