Efficacy of Hospital Cleaning Agents and Germicides Against EpidemicClostridium difficileStrains

Abstract

Objective.To compare the effects of hospital cleaning agents and germicides on the survival of epidemicClostridium difficilestrains.Methods.We compared the activity of and effects of exposure to 5 cleaning agents and/or germicides (3 containing chlorine, 1 containing only detergent, and 1 containing hydrogen peroxide) on vegetative and spore forms of epidemic and non-epidemicC. difficilestrains (3 of each). We carried out in vitro exposure experiments using a human fecal emulsion to mimic conditions found in situ.Results.Cleaning agent and germicide exposure experiments yielded very different results forC. difficilevegetative cells, compared with those for spores. Working-strength concentrations of all of the agents inhibited the growth ofC. difficilein culture. However, when used at recommended working concentrations, only chlorine-based germicides were able to inactivateC. difficilespores.C. difficileepidemic strains had a greater sporulation rate than nonepidemic strains. The mean sporulation rate, expressed as the proportion of a cell population that is in spore form, was 13% for all strains not exposed to any cleaning agent or germicide, and it was significantly increased by exposure to cleaning agents or germicides containing detergent alone (34%), a combination of detergent and hypochlorite (24%), or hydrogen peroxide (33%). By contrast, the mean sporulation rate did not change substantially after exposure to germicides containing either a combination of detergent and dichloroisocyanurate (9%) or dichloroisocyanurate alone (15%).Conclusions.These results highlight differences in the activity of cleaning agents and germicides againstC. difficilespores and the potential for some of these products to promote sporulation.