Are Antibiotics the Biggest Cause of Increasing Rates of C.Diff?

A team of researchers suggest that overuse of antibiotics are a significant contributing factor in outbreaks of Clostridium difficile (C. diff) cases.

Describing the control of C.diff infections as "an international clinical challenge," the investigators also noted that the incidence of such infections declined by roughly 80% after 2006, following the implementation of national control policies.
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For their study, the authors tested 2 hypotheses to investigate their role in this decline. First, if C. diff infection declines in England were driven by reductions in use of particular antibiotics, then it stands to reason that incidence of C. difficile infections caused by resistant isolates should decline faster than that caused by susceptible isolates across multiple genotypes. Secondly, the authors hypothesized that, if C. diff infection declines were driven by improvements in hospital infection control, then transmitted (secondary) cases should decline regardless of susceptibility.

The investigators ultimately determined that overprescribing and inappropriate use of antibiotics such as ciprofloxacin have allowed C. diff strains that were resistant to thrive, and found that cases of C. diff only decreased when fluoroquinolone use was limited and used in a more targeted way to help mitigate the effects of C. diff outbreaks.

"Our study examined C. difficile infections (CDIs) across both hospital and community settings," said Mark H. Wilcox, MD, a professor of medical microbiology at the University of Leeds, and a co-author of the study.

"While the majority of CDIs are seen in hospitalized or recently hospitalized patients, the effects of antibiotic prescribing, in terms of selecting for C. difficile types that are antibiotic resistant, will apply in both the community and hospital," said Wilcox.  

"Our study found good evidence that prescribing of fluoroquinolones provided an advantage for particular C. difficile types, some of which are unfortunately also associated with poorer outcomes," he continued. "So, antibiotics that provide a selection pressure such that some C. difficile types can thrive should be controlled in both the community and hospital. This is particularly important during outbreaks where antibiotic resistant C. difficile types may be common."

—Mark McGraw

Reference

Dingle KE, Didelot X, Quan TP, et al. Effects of control interventions on Clostridium difficile infection in England: an observational study [published online January 24, 2017]. The Lancet Infectious Disease. DOI: http://dx.doi.org/10.1016/S1473-3099(16)30514-X.