Incidence of Clostridium difficile infections in patients receiving antimicrobial and acid-suppression therapy.

STUDY OBJECTIVES: To determine the incidence of Clostridium difficile infection (CDI) at one community hospital by identifying patients with stool samples positive for C. difficile toxin A or B, and to compare the incidence with a 2008 national estimate; and to determine which patient characteristics and concomitant antimicrobial and acid-suppression drugs are risk factors for the development of CDI.

DESIGN: Retrospective, single-center, medical record review.

SETTING: 350-bed community hospital.

PATIENTS: A total of 11,010 admissions between January 1, 2009, and December 31, 2009; 115 of these patients had stool samples positive for C. difficile toxin A or B.

MEASUREMENTS AND MAIN RESULTS: All C. difficile toxin A and B enzyme immunoassay tests were performed by a central laboratory. The incidence of CDI was 10.4 cases/1000 patient admissions, which was significantly lower than the overall incidence reported in a 2008 national survey of 13.1 CDI cases/1000 patient admissions (p=0.021). Demographic and clinical data of the patients with CDI were collected by using electronic medical records. Patients were more likely to be elderly and female, and to have developed CDI during hospitalization. Of the 115 patients, 95 (82.6%) received acid-suppression therapy and 91 (79.1%) received antimicrobials. Of the patients receiving acid-suppression therapy, 72 (75.8%) received a proton pump inhibitor during their hospitalization, and 49 (51.6%) received both a proton pump inhibitor and an antibiotic. The most frequently used antibiotics in this population were fluoroquinolones, cephalosporins, and carbapenems, with a significantly larger proportion of patients who received carbapenems developing CDI compared with the other classes of antibiotics (p≤0.05 for both comparisons). Patients receiving antimicrobial and acid-suppression therapy were more likely to develop CDI than those who did not receive these drugs.

CONCLUSION: The incidence of CDI in 2009 at one community hospital was significantly lower than a 2008 national estimate. Antimicrobial and acid-suppression therapies--in particular, combinations of fluoroquinolones, cephalosporins, carbapenems, and proton pump inhibitors--were found to be risk factors for the development of CDIs in hospitalized patients.