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Contamination of surfaces by spores of Clostridium difficile is a major factor influencing the spread of healthcare-associated C. difficile infection. The aim of this study was to test the effect of an automated room disinfection system that provides an aerosol of 7.5 % hydrogen peroxide (H2O2) disinfectant, on spores of two different strains of C. difficile, and to evaluate the impact of biological soiling on the efficacy of H2O2 disinfection. The strains used were a C. difficile PCR ribotype 027 and a C. difficile ATCC 9689. Spore suspensions of each strain were applied to ceramic tiles and exposed to aerosolized H2O2 at different locations in a test room. Biological soiling was simulated by bovine serum albumin and sheep erythrocytes. At set time points spores were recovered, plated onto Columbia 5 % sheep blood agar, and surviving bacteria were counted as colony-forming units (cfu). No viable spores of either strain were recovered after a 3 h exposure to gaseous H2O2. Spores located inside a drawer showed recovery of approximately 1E5 cfu/ml for C. difficile ribotype 027 after 1 h. In the presence of organic matter, a more than fivefold log reduction compared with not exposed controls could be observed for spores of either strain tested. Appropriate decontamination of surfaces exposed to spores of C. difficile is challenging for conventional cleaning methods. Aerosolized H2O2 delivered by automated room disinfection systems could possibly improve surface decontamination and thereby reduce transmission of healthcare-associated C. difficile infection. Also in the presence of organic matter H2O2 disinfection appears to be an effective adjunct for decontamination of environmental surfaces.

Clostridium difficile is mainly considered a nosocomial pathogen associated with diarrhea and pseudomembranous colitis in hospitalized patients. Austrian hospitals reported 2761 cases of C. difficile infection (including 277 lethal outcomes) in 2007, compared with 777 cases (including 54 lethal outcomes) in 2003. The occurrence of community-acquired C. difficile infection is also increasingly reported. Recent studies have shown the occurrence of C. difficile in food and animals. The aim of the present study was to determine the occurrence of C. difficile in food and animals in Austria. Between March and July 2008, gut or fecal samples from 67 cows, 61 pigs and 59 broiler chickens were collected at Austrian abattoirs. Between February and April 2008 meat samples (51 beef [25 ground], 27 pork [17 ground] and 6 samples of chicken meat) were purchased at retail outlets. Of the 187 samples tested, eight yielded C. difficile: in cows 3/67 samples (4.5%) were positive, in pigs 2/61 (3.3%), in broiler chickens 3/59 (5%). Six of the eight isolates yielded toxigenic C. difficile (toxins A and B): 2/67 (3%) cow samples, 2/61 (3.3%) pig samples, 2/59 (3.4%) chicken samples. Genes for the binary toxin were detected in one of the two pig isolates, a PCR ribotype 126 strain. None of the 84 meat samples yielded C. difficile. The results of this Austrian study suggest that animal reservoirs are possible sources, via food, of human C. difficile infection.

From November 2008 to 15 April 2009, 36 isolates of CD027 identified in Austria, all originating from four hospitals in Vienna. All isolates were positive for toxin A, toxin B and the binary toxin, and showed a characteristic 18 bp deletion in the tcdC gene. Clostridium difficile is an anaerobic spore-forming bacterium. Some strains may cause diarrhoea due to formation of toxins. Symptomatic C. difficile infection (CDI) is primarily linked with hospital admission and antibiotic treatment, although antibiotic exposure is neither necessary nor sufficient for CDI [1,2]. In Belgium, for instance, one third of CDI cases reported in the hospital surveillance system are not hospital-associated [3]. Symptoms range from mild diarrhoea to serious manifestations such as pseudomembranous colitis, toxic megacolon or perforation of the colon. C. difficile challenges hygiene standards as it is forms spores. The risk of infection rises with increasing age, underlying disease and immunodeficiency [4]. In recent years, a particularly virulent strain, ribotype 027 (CD027), has emerged in a number of countries, particularly in connection with hospital outbreaks, but also in community-acquired diarrhoea cases [5]. The risk of serious disease and death associated with CD027 exceeds that of other C. difficile strains. The classical CD027 is characterised - among other things - by an increased production of toxins A and B, production of a binary toxin and resistance to newer fluoroquinolones such as moxifloxacin. The first three Austrian cases of CD027 occurred in 2006 and in March 2008 [6,7]. Since August 2006, the Austrian National Reference Centre for C. difficile has ribotyped approximately 2,700 human C. difficile isolates received from all nine Austrian provinces. In recent months, a drastic increase in CD027 cases has been noted, all originating from four hospitals in Vienna. From November 2008 to 15 April 2009, 36 isolates of CD027 were received at the National Reference Centre. The Figure summarises these C. difficile 027 cases by month of reception of the sample at the reference centre.