Resistance to cloxacillin among hospital staphylococci.

Cloxacillin-resistant strains of Staphylococcus aureus were detected by their ability to grow on agar containing 1.6 mug./ml. of cloxacillin, a more reliable method than the disc-diffusion test. At Sefton General Hospital, Liverpool, between 1963 and 1965, there was an increase in the number of infections among in-patients that were caused by staphylococci resistant to cloxacillin despite the fact that use of the antibiotic was largely confined to an isolation ward for patients with staphylococcal sepsis. Although there is no evidence yet that staphylococci resistant to cloxacillin will become as common in hospital practice as those resistant to penicillin and tetracycline it is clear that there is a need for continued vigilance and measures to prevent spread of staphylococci from infected patients.