Testosterone seems to play key role in bacterial skin infections

Staphylococcus aureus (staph) infections are more common in men than women, but the reason why has remained unclear until now. A team of researchers from the UT Southwestern Medical Center recently discovered that lower testosterone levels are associated with a lower likelihood of staph infections. These findings, published in Nature Microbiology, could potentially aid in the treatment of staph infections and open the door to more targeted therapies that account for biological sex differences in immune response.

“This research has important implications for treating staph skin infections and conditions complicated by Staphylococcus, such as atopic dermatitis, pemphigus, abscesses and wound infections, including the deadliest skin infections caused by MRSA [methicillin-resistant Staphylococcus aureus infection],” senior author Tamia Harris-Tryon, M.D., Ph.D., an associate professor of dermatology and immunology at UT Southwestern, said in a news release. “It also explains why men are more susceptible to staph infections.”

Testosterone is the male hormone secreted by the skin. During a staph infection, the bacteria use quorum sensing to detect neighboring cells of the same species, which allows them to spread and coordinate their attack. The bacteria produce autoinducing peptides (AIPs) as density rises, which triggers toxin release and damages host cells. Harris-Tryon and her team found that testosterone activated quorum sensing even in the absence of AIPs, suggesting the hormone may unintentionally enhance bacterial communication and virulence. The same effect was not seen in progesterone and estrogen, which are other sex hormones.

The team performed laboratory experiments using enantiomer-testosterone on mice and discovered that the male mice that were genetically engineered to produce less testosterone were the most resistant to MRSA, which can be deadly. Similarly, female mice that had testosterone applied to their skin increased the infection severity, further supporting the hormone’s role in driving bacterial activity.

Harris-Tryon explained that these findings suggest the staph bacteria can be inhibited, rather than killed, after an infection takes hold. This reduces the likelihood of antibiotic resistance and preserves the beneficial skin microbes that are important for maintaining a healthy skin barrier.

Infection appearance and prognosis

Staph is a very common bacterium, present inside the nose or on the skin of approximately 30% of the general population. An infection occurs only when there is a break in the skin, for example, through a cut or a patch of eczema, or when the immune system is compromised.

Staph infections are typically warm to the touch, tender and ooze pus. They can look like pimples, blisters, scabs or insect bites. These infections are highly contagious but usually treatable if caught early. Good hygiene, proper wound care and early medical evaluation can significantly reduce the risk of complications.

The threat of MRSA

MRSA is a type of staph infection that can be resistant to several antibiotics. If the infection spreads, it can enter the bloodstream, which can be fatal. It is not possible to tell whether a staph infection is MRSA just by looking at it; a swab must be taken and sent to a lab to confirm the diagnosis. In severe cases, the infected areas may need to be surgically drained to address the infection.