On the difficulties of isolating Clostridium difficile from hospital environments.

Spores of Clostridium difficile were deposited on to a stainless steel surface and subsequently exposed to a chlorine-releasing disinfectant (dichloroisocyanurate). Recovery of the spores was carried out using RODAC plates containing a variety of selective and non-selective agars. The non-selective agar media yielded higher recoveries of both control and chlorine-stressed spores. Our results show that the antibiotics used in selective media imposed an additional stress on both disinfectant-treated and untreated spores resulting in considerably reduced recoveries. This could lead to a serious underestimate of the extent of environmental contamination by this organism.