The nose, it seems, is protected by bacterial guards

PEOPLE ARE familiar with the idea of probiotic bacteria, which, if consumed as part of someone’s diet, are supposed to enhance the health of the gut. The gut is home to zillions of microbes of many varieties, and if this microbial ecosystem gets out of balance illness can, indeed, result. Whether consuming probiotic-rich foods such as yoghurts really does promote health is a contested area of science. But the idea that they might do so is plausible.One commonly promoted probiotic is (known as until April 15th, when its name was changed by the International Committee on Systematics of Prokaryotes in response to a report which suggested that the genus should be broken up). Now, evidence of the pathogen-fighting abilities of this bug comes from another direction—a study of the nose by Sarah Lebeer of the University of Antwerp.