A comparison of hypochlorite and phenolic disinfectants for disinfection of clean and soiled surfaces and blood spillages.

Suspension test methods were used to compare phenolic and hypochlorite disinfectants under conditions as recommended for use in hospitals. Using plasma to simulate soiled conditions, Clearsol (1% v/v) and Stericol (2% v/v) produced satisfactory disinfection, (i.e. 5 log reduction in 5 mins against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa in the presence of up to 50% v/v plasma (25 mg ml-1 plasma protein). Although sodium dichloroisocyanurate (NaDCC) at 2500 ppm AvCl2 was effective in the presence of up to 20% plasma, compared to 10% plasma for sodium hypochlorite 2500 ppm, sensitivity of NaDCC to inactivation was greater than for phenolics. In the presence of blood, both hypochlorites and phenolics were substantially inactivated, although here the effectiveness of NaDCC at 10,000 ppm was equivalent to the phenolics. Our results indicate that hypochlorites at 10,000 ppm, Clearsol 1% and Stericol 2% may be ineffective for treatment of blood spills unless applied at v:v ratios of 9 parts disinfectant to 1 part blood. In this situation, chlorine-releasing powder formulations, which produce higher AvCl2 concentrations and contain spilled material, offer an effective alternative.