Contamination of hospital disinfectants with Pseudomonas species.

During the investigation of an outbreak of infection caused by Proteus mirabilis in the infants' nursery it was found that solu tions of disinfectants in use there were contaminated with viable Gram-negative bacilli. The organisms cultured were not Proteus sp., and were quite unconnected with the outbreak. This finding prompted us to examine stocks of disinfectants in the hospital for the presence of living bacteria. Subsequent investigation showed that aqueous solutions of Hibitane (chlorhexidine) and Savlon (cetrimide-chlorhexidine mixture in the ratio 10:1) issued from the pharmacy and in use throughout the hospital were frequently contaminated with organisms identified as Pseudomonas sp. The insidious nature of this contamination and its extensiveness seemed important enough to report, as such contamination may be more wide spread than is generally supposed.