Hospital-level antibiotic use associated with rates of hospital-onset C. diff

Hospitals that significantly reduced use of all antibiotics, or specifically fluoroquinolones or third- and fourth-generation cephalosporins, achieved decreases in hospital-onset Clostridioides difficile, the retrospective study showed.

Hospitals that used more antibiotics had higher rates of hospital-onset Clostridioides difficile infection, and those that decreased antibiotic use had corresponding drops in C. diff, a recent study found.

The study examined cross-sectional and temporal associations in 2006 through 2012 between hospital-level antibiotic use and hospital-onset C. diff infections at 549 acute care hospitals. Hospital-onset C. diff was defined by presence of the ICD-9 discharge code and treatment with metronidazole or oral vancomycin three or more days after admission. Results were published by Clinical Infectious Diseases on March 1.

Overall, the rate of hospital-onset C. diff was 7.3 per 10,000 patient-days (95% CI, 7.1 to 7.5) and antibiotics were used on 811 days per 1,000 patient-days (95% CI, 803 to 820). Cross-sectional analysis found that for every 50-day per 1,000 patient-days increase in antibiotic use, there was a 4.4% increase in C. diff. For every 10-day per 1,000 patient-day increase in the use of third- and fourth-generation cephalosporins or carbapenems, hospital-onset C. diff infections increased by 2.1% and 2.9%, respectively. The time-series analysis found six hospitals that decreased their antibiotic use by at least 30% over the study, and this was associated with a 33% decrease in hospital-onset C. diff infections (rate ratio, 0.67; 95% CI, 0.47 to 0.96). Hospitals that decreased their use of fluoroquinolones or third- and fourth-generation cephalosporins by more than 20% had corresponding drops in C. diff of 8% and 13%, respectively.

This ecologic analysis, which the authors called the largest on the subject to date, supports the idea that effective antibiotic stewardship programs can have a major impact on hospital-onset C. diff infections. “Although achieving a 30% decrease in total [antibiotic use] within a hospital may represent a challenge, such reduction may be feasible in many hospitals based on findings of a recent study suggesting antibiotic use can be improved in 37.2% of the most common prescription scenarios,” they said. An effective alternative strategy might be to focus on high-risk antibiotic classes, particularly fluoroquinolones and third- and fourth-generation cephalosporins, the authors suggested. They noted that fluoroquinolone use in U.S. hospitals did drop between 2006 and 2012, without any corresponding drop in C. diff infections, so it might be most effective to concentrate particularly on replacing cephalosporins with penicillin-based drugs.

Limitations of the study include its reliance on administrative data and lack of data on changes in hospital infection control and diagnostic practices, which might have confounded the observed associations.