Prescriptions must be part of a package that includes infection control

We have seen a spectacular rise in multiresistant Staphylococcus aureus (usually termed methicillin resistant Staphylococcus aureus— MRSA) in hospitals and care homes in the United Kingdom in the past five years.1 The emergence and spread of modern resistant bacteria are not simply the result of mutations or gene transfer in the diverse species we call S aureus,2 as occurred when resistance first developed.3 Instead the resistance is now spread by the dissemination of a tiny number of clones, which have a predisposition towards resistance and have been selected by current treatment. So how does one treat staphylococcal infection?

In particular, two clones, epidemic MRSA (EMRSA)-15 and EMRSA-16, account for more than 95% of MRSA strains isolated in the United Kingdom.4 The carriage of resistance in these bacteria seems to be associated with no fitness cost—the acquisition of resistance does not slow the growth of the bacteria and thus put them at a selective disadvantage once the antibiotic is removed.5 So …