Sir, in a recent letter (BDJ 2004; 197: 115), Longman et al criticise the new recommendations on dental aspects of bacterial endocarditis (BE) prophylaxis, published by the British Cardiac Society (BCS) and the Royal College of Physicians (RCP).1

We would like to comment on this topic basing on a review of previous EB guidelines published by the Bristish Society of Antimicrobial Chemotherapy (BSAC), the American Heart Association (AHA), and the European Society of Cardiology (ESC).

Longman et al emphasise that these recommendations increase the necessity to prescribe antibiotic prophylaxis, that advise 'the use of prophylaxis for a variety of routine restorative dental procedures', and that 'the cohort of high-risk patients has been greatly increased'.

The ESC affirmed in 1995 that 'the dental procedures are the main risk factors for EB and all should be covered by antibiotic prophylaxis, except for superficial caries and bloodless supragingival prosthetic preparation'.2

Previously, the same Committee recommended prophylaxis for 'dental procedures with the risk of gingival/mucosal trauma'.3 However, Roberts et al have demonstrated that 'bleeding at the site of the operative procedure is a poor predictor of odontogenic bacteraemia',4 and that some dento-gingival manipulative procedures (including rubberdam and matrix band with wedge placement) may result in significant bacteraemia comparable to that from dental extractions.5

Longman et al stressed that placement of rubberdam, matrix band and wedge and retraction cord placement, have not been reported in the literature as causing BE; however, these represent the first step of some dental procedures including fillings or endodontic treatment which have been involved in BE development.

In addition, all 'at risk' cardiac diseases included in the new BCS–RCP recommendations had been previously gathered in the last BE guidelines from AHA6 and ESC;3 only two cardiac conditions previously considered of moderate-risk have been incorporated to the high-risk category: the Gerbode's defect and the mitral valve prolapse with mitral regurgitation or thickened valve leaflets.

Antibiotic prophylaxis is recommended in patients either at high or moderate risk of developing BE. Moreover, it has been shown that there is an increased BE incidence in patients without previously known underlying heart disease. We found in a retrospective series that this could be as high as 30% of all BE of oral origin7. In this sense, the ESC has incorporated in 2004 various non-cardiac conditions for which antibiotic prophylaxis should be administered before dental procedures.3

Longman et al also point out the unnecessary 'use of intravenous (IV) prophylaxis for certain risk groups', and they support this comment on the AHA guidelines6 where IV prophylaxis is reserved only for patients who cannot take oral medication.

Although a low compliance of IV BE prophylactic regimes by both patients and practitioners has been reported, paradoxically some practitioners may prefer to use parenteral prophylaxis in high-risk patients of BE.

Moreover, in agreement with the BCS and RCP recommendations,1 IV prophylactic regimens have been recommended by the BSAC before dental procedures under general anaesthesia and/or in patients who have had a previous BE.8

It has been proved that clindamycin is an effective antibiotic in the prevention of experimental streptococcal EB.9 However, we have recently found that in our environment clindamycin does not prevent bacteraemia following dental extractions.10 Moreover, we have also detected a high prevalence of bacteraemia caused by erythromycin-resistant streptococci11.

This is of particular concern, since the lack of erythromycin susceptibility may be associated with resistance to first-line prophylactic antibiotics such as clindamycin and azythromycin.

We have also observed that a single chlorhexidine mouthrinse reduces significantly the prevalence and duration of post-dental extraction bacteraemia.12 In a survey performed among Spanish GDPs, about 30% of patients undergoing dental extractions were administered antibiotics, and EB prophylaxis represented less than 1% of all the antibiotic prescriptions.

In summary, it seems that the use of BE prophylaxis in dentistry is not a major contributing factor to the world-wide problem of antimicrobial resistance, and we suggest that other topics such as the antibiotic of choice and the use of topical antiseptics should be submitted to deep review.