Molecular epidemiology and clinical characteristics of Clostridium difficile infection in Thailand

Background: Clostridium difficile infection (CDI) is a public health threat with high mortality and recurrence. Despite its importance, little is known about CDI in Thailand. There has been only one clinical study in the country and microbiological data are limited. Several epidemiologic studies have shown that there is a high prevalence of toxin A-negative, toxin B-positive (A-B+) and non-toxigenic C. difficile in the country, however, disease characteristics have not been determined. Methods and materials: A total of 248 adult cases were included in the CDI group and 221 patients were selected as controls. The definitions of CDI, severe CDI and recurrent CDI were according to the 2017 IDSA/SHEA guidelines. All fecal specimens were cultured for both toxigenic and non-toxigenic C. difficile and all isolates were characterized by ribotyping and toxin gene detection. Patient characteristics and laboratory data were compared between the two groups. Within the CDI group, clinical characteristics were compared between patients infected with A-B+ and A+B+ C. difficile and between patients with and without co-colonizing non-toxigenic C. difficile. Results: There were 271 toxigenic C. difficile isolated; 221 (82%) were A+B+, 47 (17%) were A-B+ and 3 (1%) were binary toxin-positive, one of which was the epidemic ribotype (RT) 078. All A-B+ strains were RT 017 which was the most common RT. Other common RTs include 014 (17%), 020 (7%) and 043 (6%). Overall, 12% (58/469) of the patients were colonized with non-toxigenic C. difficile, with no significant difference between groups. Of the CDI cases, 35% (87/248) had severe disease and 9% (22/248) experienced recurrence. The prevalence of severe cases and recurrence did not differ between patients infected with A-B+ and A+B+ C. difficile, as well as between patients with and without co-colonizing non-toxigenic C. difficile. In the control group, the most common causes of nosocomial diarrhea were drugs, with laxatives (senna, lactulose and milk of magnesia) being the most common agents. Conclusion: The epidemiology of CDI in Thailand was similar to previous reports. Toxin A-B+ strains of C. difficile caused disease with similar characteristics to A+B+ C. difficile, and protective effects of non-toxigenic C. difficile were not observed.