Fusidic acid resistance in community isolates of methicillin-susceptible Staphylococcus aureus and fusidic acid prescribing.

The level of resistance to fusidic acid among community methicillin-susceptible Staphylococcus aureus (MSSA) isolates in the UK and prescriptions for fusidic acid have both doubled over the past 6 years. It is hypothesized that selective pressure arising from topical use of fusidic acid in the community accounts for this increase. A significant correlation was found between prescribing of fusidic acid and resistance at the practice level (Spearman's rho = 0.46, 95% confidence interval 0.11-0.71, P = 0.01). Further controlled studies are required to determine whether this association is causal.