Evaluation of the sporicidal activity of different chemical disinfectants used in hospitals against Clostridium difficile

Decontamination of surfaces and medical equipment is integral to the control of Clostridium difficile transmission, and many products claim to inactivate this bacterium effectively. Thirty-two disinfectants were tested against spores of C. difficile in a suspension test based on European Standard BS EN 13704:2002, with contact times of 1 and 60min in simulations of clean (0.3% albumin) and dirty (3% albumin) conditions. The addition of a 1-min contact time was chosen as a more realistic simulation of probable real-life exposures in the situation being modelled than the 60min specified by the Standard. The manufacturer's lowest recommended concentrations for use were tested. Sixteen products achieved >10 ³ reduction in viability after 60 min (the pass criterion for the Standard) under both clean and dirty conditions. However, only eight products achieved >10 ³ reduction in viability within 1min under dirty conditions. Three products failed to reduce the viability of the C. difficile spores by a factor of 10 ³ in any of the test conditions. This study highlights that the application of disinfectants claiming to be sporicidal is not, in itself, a panacea in the environmental control of C. difficile, but that carefully chosen environmental disinfectants could form part of a wider raft of control measures that include a range of selected cleaning strategies.