Impact of an intervention to control Clostridium difficile infection on hospital- and community-onset disease; an interrupted time series analysis

P>Strategies to reduce rates of Clostridium difficile infection (CDI) generally recommend isolation or cohorting of active cases and the reduced use of cephalosporin and quinolone antibiotics. Data supporting these recommendations come predominantly from the setting of epidemic disease caused by ribotype 027 strains. We introduced an initiative involving a restrictive antibiotic policy and a CDI-cohort ward at an acute, 820-bed teaching hospital where ribotype 027 strains account for only one quarter of all CDI cases. Antibiotic use and monthly CDI cases in the 12 months before and the 15 months after the initiative were compared using an interrupted time series analysis and segmented regression analysis. The initiative resulted in a reduced level of cephalosporin and quinolone use (22.0% and 38.7%, respectively, both p < 0.001) and changes in the trends of antibiotic use such that cephalosporin use decreased by an additional 62.1 defined daily doses (DDD) per month (p < 0.001) and antipseudomonal penicillin use increased by 20.7 DDD per month (p = 0.011). There were no significant changes in doxycycline or carbapenem use. Although the number of CDI cases each month was falling before the intervention, there was a significant increase in the rate of reduction after the intervention from 3% to 8% per month (0.92, 95% CI 0.86-0.99, p = 0.03). During the study period, there was no change in the proportion of cases having their onset in the community, nor in the proportion of ribotype 027 cases. CDI cohorting and restriction of cephalosporin and quinolone use are effective in reducing CDI cases in a setting where ribotype 027 is endemic.