Molecular epidemiological analysis of Clostridium difficile infections in a Swedish County

Abstract number: P1484

Magnusson C., Wullt M., Löfgren S., Åkerlund T., Matussek A.

Objectives: This study was conducted to evaluate the occurrence of Clostridium difficile associated diarrhoea (CDAD) in a Swedish county. Furthermore, we investigate where the episodes occurred, and however possible nosocomial transmissions of certain Clostridium difficile ribotypes could be detected.

Methods: During one year from September 2000 through August 2001, all Clostridium difficile toxin positive faecal samples in the county of Jönköping were cultured and isolates were ribotyped using a PCR based method. Clinical and epidemiological data was then collected by evaluating medical records of each patient.

Results: We detected a total of 360 episodes in 284 patients (109 episodes/100.000 inhabitants) of CDAD, and a large proportion (36%) of primary episodes was community acquired. A total of 32 different ribotypes were identified, and in concordance to previous Swedish studies, the most common ribotypes were SE16, SE17, SE20 and SE21. We did not detect the virulent ribotype O27. Ribotypes SE17 and SE20 were often associated with hospital acquired CDAD, and these types had the highest transmission rates. The main part of possible transmissions occurred when patients were hospitalised on the same ward during the same time period, indicating that the hospital environment is less important as a bacterial reservoir for transmission.

Conclusion: Some ribotypes of Clostridium difficile seems to be more virulent than others. In our study, we found SE17 and SE20 to be more virulent, and others have shown this for ribotype 027. By using ribotyping, transmission data can easily be evaluated. In addition, ribotyping is of value to monitor the occurrence and spread of more virulent isolates. Thus epidemiological and hospital infection control measures can be improved to minimise spread.