Prevention of infective endocarditis.

The undiminished incidence of streptococcal endo-carditis in this country is a testimony to the failure of prophylaxis. Ninety per cent or more of medical infective endocarditis in the UK is still caused by the viridans group of streptococcil though in the United States the incidence has fallen to 50 per cent in some series probably because of a rise in the relative incidence of cases caused by intravenous drug abuse. Unfortunately , infective endocarditis is not a notifiable disease so the case load is not precisely known and is largely based on personal and published hospital series. An inspired guess suggests that there may be 1500 recognised cases a year. This means only five or six cases a year shared between the medical firms in an average sized district general hospital and perhaps 30 to 50 in a major cardiac unit. On the on hand are the general physician and his registrar who recognise infective endocarditis as a rare disease; on the other is the specialist cardiological team who mainly receive late diagnosed, specially referred, and post-cardiac surgery cases and may see a bacteriologically skewed spectrum with a high mortality. It should be possible to reason why prophylaxis has failed: (1) Perhaps it is not being given. (2) Perhaps it is not being given to the right people. (3) Perhaps it does not work. (4) Perhaps it is irrelevant. In 1977 the American Heart Association published its revised recommendations for antibiotic prophylaxis of procedures known to cause bac-teraemia.' For dental operations the committee advised intramuscular penicillin followed by oral phenoxymethyl penicillin. With even less practi-cality they advised intravenous vancomycin followed by oral erythromycin for penicillin sensitive subjects. Only two years earlier Durack, a member of this committee, had carried out a survey in Oxfordshire which showed that dental prophylaxis was administered in the then approved way in only 8 per cent of cases.3 The reason was easy to see. Most teeth are extracted under local anaesthetic outside hospital. Dentists do not prescribe intra-muscular penicillin nor do their nurses give intra-muscular injections. Most patients prefer to avoid injections anyway and are only too happy to accept oral prophylaxis, but even the most tenacious patient would find it almost impossible to achieve an intramuscular injection half an hour before an extraction in a dental surgery. Usually, therefore, tablets are prescribed, started too early, and carried on too long. Oral prophylaxis started too …