Cutibacterium acnes

Tiny living things live on your skin.

They eat oil that your skin makes.

These tiny things live in small holes. Sometimes they grow too fast. This can cause red spots called acne.

They can also live in your gut. Some can even live in plants like grapes.

Some of these tiny things glow orange. They do this under a special light.

Doctors use medicine to help clean them. This helps your skin stay healthy.

Tiny living things live on the skin of most healthy adults. We call these tiny things *Cutibacterium acnes*. They are a type of bacteria. These bacteria live deep inside pores and hair follicles.

Most of these bacteria are helpful. They are part of the normal skin flora, which means they live there naturally. They get their power from sebum. Sebum is an oily substance made by glands in your skin.

Sometimes, these bacteria grow too fast. This can happen if pores get blocked. When they grow quickly, they release enzymes. Enzymes are parts that help them digest food. These enzymes can break down the walls of the pore. This causes inflammation, which is redness and swelling. This process can lead to acne.

Many people deal with acne. It affects over 45 million people in the United States. Doctors use many ways to treat it. Some use antibiotics to kill the bacteria. Others use benzoyl peroxide. Some people use salicylic acid. This is a natural substance from plants. It helps by making the skin shed old cells.

These bacteria can also be found in other places. They live in the gut and even in grapevines. Under a special blacklight, they can glow orange!

Tiny living things called *Cutibacterium acnes* live on most healthy adult skin. These bacteria are mostly commensal, which means they live with us without causing harm. They are found in the pores and hair follicles of the skin. They can also be found in the gastrointestinal tract. Some scientists even found them living inside grapevines.

These bacteria are part of the normal skin flora. This is the group of tiny living things that naturally live on our bodies.

These bacteria need food to grow and stay healthy. They primarily eat fatty acids found in sebum. Sebum is an oily substance made by your sebaceous glands. When these glands make too much oil, the bacteria grow very fast. They also use cellular debris and other waste from the skin for energy. As they grow, they release enzymes to help them digest this food. These enzymes can break down the walls of the hair follicle. This can cause inflammation, which is redness and swelling in the skin. This is how acne vulgaris, or common acne, starts.

Scientists have spent a long time studying these tiny organisms. They were first identified as *Bacillus acnes*. Later, they were named *Propionibacterium acnes* because they make propionic acid. In 2016, researchers changed the name again. They used DNA studies to reclassify them into a new group called *Cutibacterium*. This new name helps scientists tell them apart from other similar bacteria. Researchers are still working hard to study different groups of these bacteria today.

Acne is a very common condition around the world. It affects about 650 million people globally. In the United States alone, more than 45 million people deal with it. Many people start to see acne during their teenage years. This happens because the bacteria begin to grow quickly during puberty. About 20% of all visits to a skin doctor are for acne. Doctors use many tools to help, such as antibiotics or benzoyl peroxide. Some people even use salicylic acid, which comes from plants like willow bark.

There are many interesting things to notice about *C. acnes*. If you shine a special blacklight on them, they glow orange! This happens because of things inside them called porphyrins. They are also very sensitive to certain types of light. This light can actually kill them. While they usually live on the skin, they can sometimes cause other health issues. For example, they have been found in people with certain eye or bone conditions. They are a small but very busy part of our world.

*Cutibacterium acnes* is a type of bacterium that lives on human skin. It is a gram-positive, rod-shaped bacterium that grows relatively slowly. This organism is mostly commensal, meaning it lives on healthy people without causing harm. It is a major part of the normal skin flora found on most adults. However, it is also linked to several medical conditions. The most common is acne vulgaris, a chronic inflammatory disease.

These bacteria live primarily deep within the hair follicles and pores. To survive, they need specific nutrients to produce energy. They mostly eat fatty acids found in sebum, which is an oil produced by sebaceous glands. They also use cellular debris and metabolic byproducts from surrounding skin tissue. When sebaceous glands become hyperactive, they produce more sebum. This process is called sebaceous hyperplasia. If a follicle becomes blocked, the bacteria can grow and multiply very quickly.

As *C. acnes* grows, it performs several complex biological tasks. The bacteria secrete many proteins, including several digestive enzymes. These enzymes help the bacteria digest sebum to acquire nutrients. They can also destabilize the layers of cells that form the follicle walls. The rapid growth of the bacteria produces metabolic byproducts and bacterial debris. This buildup can trigger inflammation in the skin. This inflammation leads to the symptoms of acne and folliculitis.

Scientists have changed the name of this bacterium several times. It was originally identified as *Bacillus acnes*. Later, it was named *Propionibacterium acnes* because it generates propionic acid. In 2016, researchers reclassified it again due to new genomic studies. They used DNA G + C content and phylogenetic tree structures to distinguish it. This led to the creation of the new genus *Cutibacterium*. This new group includes species formerly known as *P. avidum* and *P. granulosum*.

Acne is a massive global health issue. It affects approximately 650 million people around the world. In the United States, more than 45 million individuals are affected. About 20% of all dermatologist visits are for acne-related issues. The bacteria often begin to colonize the skin 1 to 3 years before puberty. During puberty, the bacteria grow exponentially. This is why many teenagers and young adults experience breakouts. Doctors often treat this with antibiotics like erythromycin or doxycycline.

However, the bacteria are becoming harder to treat. Antibiotic resistance is a growing problem in North America and Europe. In 1979, resistance was at 20%, but it rose to 64% by the year 2000. Because of this, doctors often combine antibiotics with benzoyl peroxide. Some patients with severe acne use isotretinoin. Other treatments include salicylic acid, which is derived from white willow bark. Salicylic acid can reduce lipid synthesis in sebocytes, the cells that make sebum.

*C. acnes* can also be found in unexpected places. It has been found in the gastrointestinal tract and even in plants. A specific subtype called *Zappae* lives inside grapevines. This subtype diverged from human strains about 7,000 years ago. In humans, the bacteria can sometimes cause other problems. It is a common cause of endophthalmitis after cataract surgery. It has also been found in herniated discs and is linked to certain bone and eye conditions.