Background: In recent years, toxigenic Clostridium difficile infection (CDI) has been the cause of C. difficile-associated
diseases (CDAD), resulting in increasing hospitalization, community infection outbreak and mortality all over the world.
Objective: To investigate the prevalence of toxigenic C. difficile strains in Rajavithi Hospital.
Material and Method: This was a retrospective study of data from C. difficile toxin tests at Rajavithi Hospital’s microbiology
laboratory from January 1, 2009 to June 30, 2015.
Results: Of the 5,821 stool specimens tested for C. difficile toxin, 561 (9.6%) were positive for toxigenic C. difficile strains
(10.2%, 7.6%, 5.6%, 9.6%, 9.7%, 15.4% and 12.0% respectively from year 2009 to 2015). The samples of all 453
unrepeated patients with this toxigenic C. difficile strain were analyzed. Two hundred and fifty-six (56.5%) of the patients were female, and the highest prevalence (58.3%) of toxigenic C. difficile strains was found in those aged over 65 years old. Overall, 7.7% of toxigenic C. difficile strains were isolated from OPD while the other 92.3% were from IPD. The majority of these
strains (73.0%) were isolated in patients from the internal medicine wards, followed by surgery wards, intensive care units
(ICUs), gynecology wards, radiation oncology wards and orthopedic wards at 8.9%, 6.2%, 2.4%, 2.2% and 1.1%, respectively.
Conclusion: The prevalence of toxigenic C. difficile strains at Rajavithi Hospital was not high. The occurrence of these strains, recorded for each month of the study period, showed an irregular trend, but by far the highest frequency was found
in older age groups. Rapid and accurate detection is necessary to enable immediate treatment and to stop the spread of
infection. In future, these strains will be studied at a molecular level and antimicrobial susceptibility testing will be performed
and the results entered in a database of toxigenic C. difficile strains in Thailand.

Keywords: Clostridium difficile, prevalence, toxin, Thailand