Study Finds Fidaxomicin More Effective Than Metronidazole, Vancomycin for Clostridioides difficile Infection

Woman Hand Holding Blister Pack
Investigators assessed whether choice of antibiotic has an impact on shedding of Clostridioides difficile spores in hospitalized patients.

Shedding of Clostridioides difficile was found to be more effectively reduced with fidaxomicin therapy compared with vancomycin and metronidazole, according to results of a prospective, randomized trial published in Clinical Infectious Diseases.

Hospitalized patients (N=31) diagnosed with C difficile infection between 2014 and 2017 were randomly assigned to receive either oral metronidazole 500 mg every 6 hours (n=10), oral vancomycin 125 mg every 6 hours (n=10), or oral fidaxomicin 200 mg every 12 hours (n=11) for at least 10 days. C difficile shedding was assessed in patient stool and on 5 high-touch surfaces.

The median age of patients was 61 years (interquartile range [IQR], 55-70); 48% were women.

C difficile was detected on at least 1 surface for most patients (74%). Surfaces found to be contaminated most frequently included the bathroom floor (27.0%) and toilet (17.7%). Contamination varied on the basis of antibiotic therapy; patients on metronidazole had the highest contamination rate (21.4%; 95% CI, 18.0-25.2), followed by fidaxomicin (13.1%; 95% CI, 10.7-15.9; P =.04) and vancomycin (6.3%; 95% CI, 4.7-8.3; P <.01).

Baseline C difficile shedding was associated with environmental contamination (odds ratio [OR], 1.99; 95% CI, 1.35-2.93 per log10 colony forming units [CFU]/g stool; P <.01). Only patients receiving fidaxomicin therapy were found to be associated with reductions in environmental contamination over time (OR, 0.83; 95% CI, 0.70-0.99; P =.04).

In stool, shedding declined more rapidly among patients on fidaxomicin (-0.36; 95% CI, -0.52 to -0.19 per log10 CFU/g stool; P <.01) or vancomycin (-0.17; 95% CI, -0.34 to -0.01 per log10 CFU/g stool; P =.05) compared with metronidazole (-0.01; 95% CI, -0.10 to 0.08 per log10 CFU/g stool).

Most patients were infected with a single ribotype (92.6%), and 88.8% of patients were infected with the ribotype detected in their room.

This study may have been limited by its small sample size and unblinded design.

These data indicate that C difficile shedding and environmental contamination were more greatly reduced with fidaxomicin compared with metronidazole or vancomycin therapies.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Turner NA, Warren BG, Gergen-Teague MF, et al. Impact of oral metronidazole, vancomycin, and fidaxomicin on host shedding and environmental contamination with Clostridioides difficile. Clin Infect Dis. Published online May 21, 2021. doi:10.1093/cid/ciab473