Contaminated first-aid dressings: report of a working party of the PHLS.

In a collaborative study 12 Public Health Laboratory Service laboratories and the Division of Hospital Infection, Central Public Health Laboratory, investigated the degree of contamination of standard dressings produced by manufacturers in India or in England by a comparison of the results of culture of 25 sterilized dressings with those of 25 untreated dressings. Of the 38 batches of dressings made in India 27 (71%) were judged contaminant and another six could be so judged when Bacillus species were examined. In two batches laboratory contamination precluded a judgement and only three batches passed the test. Of the 27 batches made in England, only three gave any evidence of contamination at the lowest level of significance. Repeat investigation of one of these batches gave no evidence of contamination. Organisms of the genus Bacillus and fungi were associated with contamination; micrococci and propionibacteria were laboratory contaminants. There was evidence for both failure and sterilization and of contamination after sterilization during the manufacture of dressings.