Final answer:
Propionibacterium acnes thrives in the sebaceous glands by consuming components of sebum, which is food for the bacteria. Despite sebum's inhibitory properties for other microbes, P. acnes can use its non-inhibitory components for nutrition and secretes enzymes causing inflammation leading to acne.
Step-by-step explanation:
Propionibacterium acnes is a slow-growing, aerotolerant anaerobe that thrives in human sebaceous glands, despite the antibacterial components of sebum. The bacterium is uniquely adapted to survive and use the sebum as a source of nutrition, thus playing a pivotal role in the development of acne. While some lipids and fatty acids in sebum can inhibit microbial growth, P. acnes is capable of utilizing the non-inhibitory components as food. To establish an infection, P. acnes secretes enzymes which damage the hair follicle and cause inflammation. This process leads to the characteristic inflammatory lesions of acne such as papules, pustules, nodules, or pseudocysts. The bacteria can persist on the skin due to its ability to exploit the nutrient-rich environment provided by sebum, turning what is an antibacterial substance for other microbes into a resource for its own survival.