a1 Departments of Medical Microbiology and Pharmacy, St Bartholomew's Hospital, West Smithfield, London, EC1A 7BE
a2 Department of Bacteriology, St John's Hospital for Diseases of the Skin, Homerton Grove, London E9 6BX
Topical medicaments used by patients with diseases of the skin were examined for microbial contamination. Ps. aeruginosa was isolated from stock pots of a diluted emulsifying ointment used as a soap substitute in the bath. Cross-con tamination between patients and medicament was subsequently shown to have occurred.
(Received May 28 1979)