Anyone due for a medical examination would be well advised to steer clear of their doctor's stethoscope. If British doctors are anything like their US counterparts, it will probably harbour all kinds of bacteria. A study of 150 staff in a Michigan Hospital, published in the Annals of Emergency Medicine, found that while doctors and nurses regularly washed their hands, they were not so careful about their stethoscopes - almost 6 per cent said they had never been cleaned at all. Almost every stethoscope examined contained bacteria, while one in five were contaminated with Staphylococcus aureus, which can cause serious

infections. Patients with weakened immune systems or skin conditions such as eczema could be particularly vulnerable to dirty stethoscopes.