Colonisation and transmission of Clostridium difficile in healthy individuals examined by PCR ribotyping and pulsed-field gel electrophoresis

Healthy adults who had not been exposed to antimicrobial agents for the pre ceding 4 weeks were examined for intestinal carriage of Clostridium diffici le. The 1234 individuals examined were composed of seven groups: three clas ses of university students, hospital workers at two hospitals, employees of a company and self-defence force personnel at a local station. Overall, 94 (7.6%) individuals were positive for C. difficile by faccal culture but ca rriage rates among the study groups ranged from 4.2% to 15.3%, Typing by PC R ribotyping and pulsed-field gel electrophoresis demonstrated clusters of carriers colonised by a single type in each of three groups, indicating tha t cross-transmission of C. difficile can occur in community settings. Follo w-up culture was performed on 38 C, difficile-positive individuals and C. d ifficile was isolated again from 12 (32%) of them 5-7 months after the init ial culture; sis (50%) of these 12 individuals had a new strain on repeat c ulture. Two or more family members were C. difficile-positive in five of 22 families examined. C. difficile with an identical type was isolated from p el sons within a family in only one family. These results suggest that inte stinal carriage by healthy adults may play a role as a reservoir for commun ity-acquired C. difficile-associated diarrhoea, but that cross-transmission of C, difficile does not occur frequently among family members at home.