Efficacy and contamination of in-use disinfectants in Rajavithi General Hospital.

Quality testing of disinfectant in-use in Rajavithi General Hospital was conducted to evaluate the germicidal activity and contamination. Two hundred and thirty-four samples of 4 commonly used disinfectants in operating rooms, labour rooms and the surgical intensive care unit were studied. Results showed that 2 of 126 samples of chlorhexidine/cetrimide 1:100 dilution were contaminated by P.maltophilia and A.xylosoxidans and failed the in-use test. One of 34 samples of phenolics yielded A.lowffii. Two of 16 hypochlorite 0.05% grew E.cloacae, Enterobacter spp., A.calcoaceticus and Pseudomonas spp. Forty-six samples of 1:500 and 1:100 of quaternary ammonium compound, and 12 samples of 1% hypochlorite were not contaminated. Bacterial contamination and failure to kill bacteria by disinfectants reflected improper preparation and use of these solutions. Periodic quality testing is clearly indicated.