An outbreak of Clostridium difficile-associated disease (CDAD) in a German university hospital

Abstract

We investigated an outbreak of Clostridium difficile (CD)associated disease (CDAD) in a cardiac surgical department that took place between January 25th and April 28th 2007 at Hannover Medical School, Germany. Immediate infection control measures such as changing the surface disinfectant from an alcohol-based glucoprotamine to an oxygen-active disinfectant cleaner and the primary education of staff were proved to be insufficient to control the outbreak. Therefore, a “CD infection control bundle” was created consisting of: (a) implementation of a CDAD outbreak team; (b) education on hand hygiene; (c) the aim of early case finding as soon as clinical symptoms of CDAD were noticed; (d) daily control of microbiological results; (e) suggesting proper antimicrobial therapy of patients on the ward avoiding high-risk substances; (f) reinforcement of currently existing infection control measures, such as including the isolation of CDAD cases in single rooms; (g) and, finally, interim closure of the unit for any new admissions. For the treatment of CDAD, initially, metronidazole and, in the case of failure of initial therapy, oral vancomycin were used. A case–control study was performed. Cases were defined as proposed by the ECDC: (a) onset of diarrhoea ≥48 h after admission or ≥4 weeks after the most recent discharge and (b) positive enzyme-immunoassay (EIA) for CD toxins A or B in stool samples (RIDASCREEN® Clostridium difficile Toxin A/B test, R-Biopharm, Glasgow, United Kingdom) or the culturing of toxin-producing CD (Clostridium difficile-selective media, Oxoid, Hampshire, United Kingdom). The results of Gram strain, colony morphology and biochemical testing with the RapID II ANA System® (Remel, Lenexa, USA) were used for species determination. Cultured strains were examined by pulsed field gel electrophoresis (PFGE) using GelCompar II® software (Applied Maths NV, Sint-Martens-Latern, Belgium) and by polymerase chain reaction (PCR) ribotyping, as described by others [1]. Antimicrobial susceptibility testing was performed by E-test® (AB Biodisk, Solna, Sweden) on agar plates containing vitamin K1, haemin and 5% defibrinated sheep red blood cells (Inverness Medical Deutschland, Cologne, Germany). Breakpoint minimal inhibitory concentrations (MICs) were ≥8 μg/mL for fluoroquinolones (FQ) [2] and ≥4 μg/mL for erythromycin [3]. Severe CDAD was defined as readmission because of relapse, necessity of intensive care because of CDAD, surgical procedure due to CDAD or CDAD contributing to the patient’s death within 30 days after diagnosis [4–6]. Controls were diarrhoeal patients admitted to the same unit during the same time period but were negative for CD toxin EIA, including CD culture (= confirmed CD negative) and negative for other gastrointestinal infectious agents. Age, gender, co-morbidities, underlying diseases, endoscopic procedures, history of antimicrobial exposure, readmission and relapse of CDAD in both groups were Eur J Clin Microbiol Infect Dis (2009) 28:543–545 DOI 10.1007/s10096-008-0655-7