Fusidic acid should be used with restraint

EDITOR—Koning et al report the results of a clinical trial that showed the efficacy of topical fusidic acid as treatment of patients with impetigo.1 This agent has been recommended by the Dutch College of General Practitioners as the treatment of choice in patients with this infection. Koning et al observed that none of the pretreatment isolates of Staphylococcus aureus was resistant to fusidic acid and concluded that many years of use of topical fusidic acid has not resulted in appreciable resistance in staphylococci in the general population.

These findings illustrate one of the problems surrounding antimicrobial resistance—namely, that patterns of resistance in one country cannot be extrapolated to those in another. Specifically, data for resistance rates to fusidic acid among S aureus isolates in the United Kingdom differ markedly from those in the Netherlands. In a survey of 28 centres in the United Kingdom the incidence of resistance to fusidic acid among S aureus isolates from the community (excluding strains of methicillin resistant S aureus, which, by their clonal nature, might distort the data) increased from 8.1% in 1995 to 17.3% in 2001 (figure) (R Wise, unpublished data).2 A similar study carried out in Bristol showed an approximately twofold increase in resistance rates (from 6% to 11.5%) among methicillin susceptible S aureus strains isolated between 1998 and 2001.3

The figure also shows that between 1995 and 2001 the number of prescriptions of fusidic acid in the United Kingdom (expressed as total units dispensed and accounted for almost entirely by the topical formulation) nearly doubled (data supplied by Leo Pharmaceuticals).

We cannot explain why the Dutch experience does not mirror our own, although Koning et al have not …