Tetracyclines may reduce risk for C. difficile

Use of tetracyclines was associated with a decreased risk for Clostridium difficile infection, a meta-analysis found.

“Antibiotics associated with a high risk of C. difficile infection, or CDI, are fluoroquinolones, clindamycin, broad-spectrum cephalosporin and penicillin,” Sahil Khanna, MBBS, an internist and gastroenterologist at the Mayo Clinic, and colleagues wrote. “Patients receiving aminoglycosides, metronidazole, vancomycin and tetracyclines, however, may be at lower risk for CDI.”

The researchers performed a search of the MEDLINE, Embase and Web of Science databases for studies that evaluated associations between tetracyclines and risk for CDI.

Khanna and colleagues reviewed four case-control studies and two cohort studies, with all patients recruited between 1993 and 2012. In a random effects model, use of tetracyclines was associated with a decreased risk for C. difficile compared with other antibiotics, the researchers reported (OR = 0.62; 95% CI, 0.47-0.81). Khanna and colleagues wrote that the studies demonstrated “significant heterogeneity.” The researchers reported no publication bias.

A subgroup analysis showed that doxycycline in particular was associated with a decreased risk for CDI (OR = 0.55; 95% CI, 0.4-0.75).

The researchers wrote that the analysis was limited by differences in study design, patient population, dose and duration of tetracycline use; method of CDI diagnosis; and period of antibiotic exposure, which were the drivers of heterogeneity among the studies. Further, none of the studies evaluated outpatients exclusively, meaning Khanna and colleagues could not differentiate between inpatient and outpatient therapy.

“This study suggests that tetracycline use (particularly doxycycline) may be associated with a decreased risk of future development of CDI compared with other antibiotics,” the researchers wrote. “However, given the discrepancies seen on subgroup analyses, further comparative studies should be performed in settings in which tetracyclines are still effective therapeutic agents.” – by Andy Polhamus

Disclosures: The authors report no relevant financial disclosures.