A case-control study found major differences in risk for community-onset C. difficile infection among patients receiving different oral antibiotics.

The rising incidence of hospital- and community-acquired Clostridioides difficile infection (CDI) reinforces the need for more effective prevention. Researchers performed a retrospective case-control study to examine relative risk for community-acquired CDI in patients receiving different oral antibiotics. Using US administrative claims databases from 2001 to 2021 that included commercial, Medicare and Medicaid records, they matched each community-acquired CDI case with five control patients for a total of 159,404 cases and 797,020 controls.

For cases occurring within 30 days of antibiotic exposure, the highest risk for community-acquired CDI occurred with clindamycin (adjusted odds ratio [AOR], 25.4) and the lowest with minocycline (AOR, 0.79; the only one of 27 oral antibiotics with an AOR below 1.0). Other high-risk antibiotics were cefixime (AOR, 12.0), cefdinir (11.0), cefuroxime (9.6), cefpodoxime (9.2), amoxicillin-clavulanate (8.5) and ciprofloxacin (6.8). Older beta-lactams were lower risk (penicillin AOR, 1.8; amoxicillin, 2.0; cephalexin, 2.9; cefadroxil, 2.8). The lowest-risk antibiotic classes were the macrolides, sulfonamides and tetracyclines. For all antibiotic classes, different agents had discernible differences in AOR for community-acquired CDI.

A sensitivity analysis assessing relative risk for community-acquired CDI over multiple exposure periods up to 180 days found that the relative hierarchy of risk for the different antibiotics remained the same for each exposure period, and that overall risk progressively declined with time.

Comment: The authors acknowledge multiple limitations of their analysis, including use of administrative claims data to identify community-acquired CDI and outpatient claims data to identify antibiotic exposure and lack of information on inpatient antibiotic usage. Still, the large study population allowed for a more-precise definition of relative risk than in prior studies, not only showing a wide variation among beta-lactam antibiotics but also indicating that the risk associated with fluoroquinolone antibiotics falls between that of the older and newer cephalosporin classes.

Richard T. Ellison III, MD, Professor of Medicine, Microbiology and Physiological Systems, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, USA.

Miller AC, et al. Comparison of different antibiotics and the risk for community-associated Clostridioides difficile infection: a case-control study. Open Forum Infect Dis 2023 Aug 5; 10: ofad413.

This summary is taken from the following Journal Watch titles: Infectious Diseases, General Medicine, Hospital Medicine, Ambulatory Medicine.