Rapid analysis of Clostridium difficile strains recovered from hospitalized patients by using the slpA sequence typing system

Clostridium difficile is a nosocomial pathogen that is transmissible between patients via hospital staff and via contaminated environmental surfaces. Recently, a typing system based on the slpA sequence for C. difficile was developed. To elucidate the validity and efficacy of the system in the setting of a local hospital, we carried out typing of C. difficile from patients in our hospital using the system. Twenty-eight stool samples obtained from 17 patients with C. difficile-associated diarrhea were investigated. Twenty-two of the 28 samples were positive for C. difficile by stool culture, and they were able to be classified by slpA sequence typing. The smz-1 and smz-2 strains were revealed to be the predominant types in our hospital, accounting for 73% of all strains. The yok-1, yok-2, t25-1, hr-1, and hj2-2 strains were identified in 1 patient each. The smz-1 strain was identified in all wards except for ward D, while smz-2 was identified in 3 of 4 patients in ward D and was restricted to this ward. Nosocomial infection of smz-1 and smz-2 in our hospital was demonstrated. Distinguishing smz-1 from smz-2 by slpA sequence typing clarified the transmission of C. difficile among patients. In conclusion, slpA sequence typing was useful in the setting of a local hospital and may be a powerful tool for the epidemiological study of C. difficile infection.