Efficacy of decontaminants and disinfectants against Clostridium difficile

Abstract

Clostridium difficile is a common nosocomial pathogen transmitted mainly via its spores. These spores can remain viable on contaminated surfaces for several months and are resistant to most commonly used cleaning agents. Thus, effective decontamination of the environment is essential in preventing the transmission of C. difficile in health-care establishments. However, this emphasis on decontamination must also be extended to laboratories due to risk of exposure of staff to potentially virulent strains. Though few cases of laboratory-acquired infection have been reported, the threat of infection by C. difficile in the laboratory is real. Our aim was to test the efficacy of four disinfectants, Actichlor, MicroSol 3+, TriGene Advance and Virkon, and one laboratory decontaminant, Decon 90, against vegetative cells and spores of C. difficile. Five strains were selected for the study: the three most commonly encountered epidemic strains in Scotland, PCR ribotypes 106, 001 and 027, and control strains 630 and VPI 10463. MICs were determined by agar dilution and broth microdilution. All the agents tested inhibited the growth of vegetative cells of the selected strains at concentrations below the recommended working concentrations. Additionally, their effect on spores was determined by exposing the spores of these strains to different concentrations of the agents for different periods of time. For some of the agents, an exposure of 10 min was required for sporicidal activity. Further, only Actichlor was able to bring about a 3 log 10 reduction in spore numbers under clean and dirty conditions. It was also the only agent that decontaminated different hard, non-porous surfaces artificially contaminated with C. difficile spores. However, this too required an exposure time of more than 2 min and up to 10 min. In conclusion, only the chlorine-releasing agent Actichlor was found to be suitable for the elimination of C. difficile spores from the environment, making it the agent of choice for the decontamination of laboratory surfaces.

A systematic evaluation of a peracetic-acid-based high performance disinfectant

“…Of the microorganisms associated with HAI, Clostridium difficile (C. difficile) (Malamou-Ladas et al, 1983, Kim et al, 1981 represents the most significant disinfection challenge due to: the innate disinfection resistance of C. difficile spores (Tumah, 2009, Maillard, 2011, their environmental persistence (Kramer et al, 2006), the large numbers of spores excreted (Mulligan et al, 1979) and their low infective dose (Sambol et al, 2001). The requirement for disinfectants able to inactivate C. difficile spores, and the limited number of sporicides (Tumah, 2009, Lambert, 2004, has resulted in the domination of chlorine based products (Vohra andPoxton, 2011, Fraise, 2011). This dominance is reflected in UK guidance (DoH andHPA, 2009, Pratt et al, 2007) where products delivering 1,000ppm free available chlorine (FAC) are recommended for cleaning associated with patients with C. difficile infections (CDI), in the presence of blood 10,000 ppm FAC is recommended (DoH, 1998).…”

The Phosphotransfer Protein CD1492 Represses Sporulation Initiation in Clostridium difficile

“…During infection, a subset of C. difficile vegetative cells initiates the process of sporulation and morphologically transforms into spores (5,6). These spores are metabolically dormant and highly resistant to oxygen, heat, and chemicals that would destroy the vegetative form of C. difficile (7)(8)(9).…”

Synergistic efficacy of 405 nm light and chlorinated disinfectants for the enhanced decontamination of Clostridium difficile spores

“…In a study carried out by Vohra et al, five disinfectants were successful for inhibition of the growth of C. difficile vegetative cells, in comparison to spore inactivation in which only Actichlor was found to achieve 3 log 10 reduction under clean and dirty conditions [27]. Furthermore, It was also the only agent that decontaminated a range of non-porous surfaces artificially contaminated with C. difficile spores [27]. This increased resilience of spores in comparison to vegetative cells is further supported by a study demonstrating that, following induction of spore germination, C. difficile becomes much more susceptible to inactivation by UV-C radiation and heat, due to the restoration of vegetative cell properties and irreversible loss of spore properties [28].…”

“…difficile spores following a 50 minute exposure to UV-C [26]. In a study carried out by Vohra et al, five disinfectants were successful for inhibition of the growth of C. difficile vegetative cells, in comparison to spore inactivation in which only Actichlor was found to achieve 3 log 10 reduction under clean and dirty conditions [27]. Furthermore, It was also the only agent that decontaminated a range of non-porous surfaces artificially contaminated with C. difficile spores [27].…”