Infective endocarditis (IE) is an elusive condition which continues to challenge all those involved in its investigation and management.1 Cardiologists, who often encounter patients with severe complications of the disease destined for complex cardiac surgery or post mortem are naturally fearsome of its consequences and have traditionally maintained the dogma of prevention by antibiotic prophylaxis before invasive procedures. The evidence to support this stance is limited, however, and revision of European and US guidelines in recent years has resulted in a major shift of emphasis in this contentious area. Dramatic guidance from the UK National Institute for Health and Clinical Excellence (NICE) published last month2 now seems set to generate further controversy and confusion in the minds of cardiologists, dentists and their patients. What future therefore for this practice?

CHANGING EPIDEMIOLOGY AND EVIDENCE TO DATE

The clinical profile of valve disease is changing in developed nations with an increasing proportion of elderly patients.3 The past two decades have also witnessed major changes in the demography of IE, with increasing incidence of Staphylococcus aureus (with attendant higher mortality), often acquired as a result of nosocomial infection or intravenous drug abuse, and falling incidence of IE secondary to oral streptococci.4 Furthermore, IE often arises in patients without previously documented cardiac disease (47% in one recent French series) when the question of prophylaxis is irrelevant.5

Even if antibiotic prophylaxis is applied appropriately, the evidence to support its efficacy is limited. Indeed, a recent Cochrane review concluded that there was no evidence to demonstrate whether penicillin prophylaxis is effective or ineffective in preventing IE in patients at risk undergoing an invasive dental procedure.6 Routine daily oral activities (eg, tooth brushing and chewing) cause transient streptococcal bacteraemia, the cumulative result of which is an annual bacteraemic exposure thousands …