Early colonization by S. aureus and protection from atopic eczema

Abstract

Atopic eczema causes itchy skin and sleepless nights. It is also connected to increased risk of developing asthma and hay fever. Like these allergic diseases, atopic eczema is common in Western societies, but uncommon where poverty and poorer sanitary conditions prevail. Therefore, lack of immune stimulation (meaning exposure to certain bugs or ‘microbes’ that help the immune system develop) during infancy might underlie these diseases. Staphylococcus aureus it is a bacterium which lives on our skin and also commonly colonizes (lives and multiplies in) the gut of infants, where it can reach quite high numbers. It can produce toxins known as “superantigens”, which are commonly known as causing ‘food poisoning’. However, this study suggests that it may actually be good for babies to be colonized by S. aureus in the gut. Certain S. aureus strains appear to reduce the risk of the baby developing eczema. The researchers followed a group of infants from birth onwards. They cultured (took samples and grew in the lab) S. aureus from the babies’ stools up to two months of age and characterized the strains regarding whether they carry genes for superantigens and certain proteins called adhesins. The scientists suggested that, whereas the rate of gut colonisation by S. aureus does not differ between infants who develop atopic eczema or those who do not, infants without eczema more often carry S. aureus strains in their gut that produced the egc type of superantigens and elastin‐binding adhesin. The authors speculate that in today's clean environment, colonization by S. aureus may help to kick‐start the babies’ immune system, which previously occurred naturally in a less hygienic environment. Perhaps, an eczema‐preventing drug might be developed in the future using immune activating components of S. aureus.