Molecular epidemiological analyses of isolates in a university hospital in Japan.

Background: We performed molecular epidemiological analyses of isolates in a university hospital in Japan to reveal the risk of infection.

Methods: Cultured isolates from 919 stool samples from 869 patients obtained from July 2015 to August 2016 were subjected to toxin gene detection, ribotyping, multilocus sequence typing, antimicrobial susceptibility testing, and quantitative real-time polymerase chain reaction testing for toxin gene expression.

Results: Of the 919 stool samples from 869 patients, was isolated from 153 samples (16.6%), of which 49 (32%) and 104 (68%) were from patients with and without infection, respectively. Analyses showed genetic diversity, with ST8 and ST17 strains of healthcare-associated infections, some of which caused infections. There was no significant difference in the transcription levels of toxin genes between isolates from patients with and without infection.

Conclusions: Major Japanese clonal strains, ST8 and ST17, have been in the hospital environment for a long time and cause healthcare-associated infections. The C. toxin genes were transcribed in the isolates from both patients with and without infection but were no significant relationship with the development of infection.