Though we do our best to counteract it with antiperspirant and air-conditioning, sweat may actually be a good thing. According to a new study, human sweat contains an antimicrobial proteindubbed Dermcidinthat acts against a wide range of pathogenic organisms. As such, it may help stave off infection. Birgit Schittek of the Eberhardt-Karls-University in Tbingen, Germany and her colleagues, who isolated the gene that codes for Dermcidin, announced their findings in a report published online today by the journal Nature Immunology.
Earlier work had revealed two classes of antimicrobial proteins in mammalian skin, one expressed by cells known as keratinocytes and the other by a variety of skin cell types. Dermcidin, however, bears no meaningful resemblance to the previously known proteins and is expressed only in sweat glands, where it is secreted into sweat and then ferried to the skin surface.
To evaluate Dermcidin's antibiotic properties, the researchers tested the activity of its derivatives against several pathogens under pH and salt conditions characteristic of human sweat. It proved remarkably effective against the bacteria Escherichia coli, Enterococcus faecalis and Staphylococcus aureus. The sweat-dwelling protein also exhibited strong antifungal capabilities, squelching the yeast Candida albicans. Dermcidin, the authors conclude, "may help limit infection by potential pathogens in the first few hours following bacterial colonization." They note, though, that whether it can combat microorganisms that are resistant to established antibiotic therapies remains to be determined.