The epidemiology of infection withPseudomonas pyocyaneain a burns unit

Abstract

A bacteriological study of burned patients and of the staff and environment in a burns unit was made with the purpose of discovering the principal reservoirs and routes of transfer ofPs. pyocyanea.Infected burns appeared to be the most important reservoirs. About 3 % of the stools of normal subjects and of patients with intestinal symptoms carried the organism, which was also isolated from the nose, throat, nasopharynx, skin and ear of a small proportion of patients and staff in the burns wards.The hands of nurses in the wards were often contaminated withPs. pyocyanea, and presented a likely vector in the transfer of the organism by contact—e.g. from the bandages of infected patients, and from furniture and other objects near to their beds.It was shown by slide agglutination that a new type ofPs. pyocyaneaadmitted to one of the wards spread freely in that ward but hardly at all to the other ward. Since patients from both wards used the same dressing station and operating theatres, it seemed from this finding that a large proportion of the cross-infection occurred in the wards.Polymyxin dusting powder was shown in a controlled trial to protect exposed burns against contamination byPs. pyocyanea.These results are discussed in relation to the mechanism of transfer of the organism and the methods of preventing cross-infection. The need to use several methods concurrently is emphasized, since none of those which have been investigated contributes more than a partial effect. Cubicle wards are advocated, since much cross-infection is shown to occur in open wards.We are much indebted to Dr G. T. Cook for kindly letting us use results obtained by him at the Oxford Public Health Laboratory. We also wish to thank Prof. J. F. D. Shrewsbury of Birmingham University and our colleagues at the Birmingham Accident Hospital for their valuable co-operation, and Dr A. C. Cunliffe of King's College Hospital for information on the typing ofProteusfrom patients in our wards.