C. diff-related bloodstream infection seen less often with FMT vs. antibiotics

While fecal microbiota transplantation (FMT) was associated with fewer bloodstream infections than antibiotics in one study, a brief report described two cases of drug-resistant bacteremia transmitted by FMT.

Treatment with fecal microbiota transplantation (FMT) rather than antibiotics for recurrent Clostridioides difficile infection was associated with a lower incidence of primary bloodstream infection, a prospective cohort study found.

Researchers enrolled 290 patients who were hospitalized from July 2013 to May 2018 with recurrent C. difficile infection at an academic medical center in Italy. Eligible patients were adults who had their first observable episode of recurrent C. difficile infection at the hospital and did not develop a secondary bloodstream infection from a known source. The primary outcome was the incidence of primary bloodstream infection within 90 days. Secondary outcomes were length of hospitalization and overall survival at 90 days. Results were published on Nov. 5 by Annals of Internal Medicine.

The prospective study looked at 109 patients treated with FMT and 181 treated with antibiotics. Five of the FMT patients and 40 patients on antibiotics developed bloodstream infections. Due to differences between groups in many baseline characteristics, the researchers performed comparative analyses in a propensity-matched cohort (57 patients per treatment). Risk for bloodstream infection was 23 percentage points (95% CI, 10 to 35 percentage points) lower in the FMT group, which also had 14 fewer days of hospitalization (95% CI, 9 to 20 fewer days) and a 32-percentage point increase in overall survival (95% CI, 16 to 47 percentage points) compared with the antibiotic group.

Limitations of the study include its observational nature and single-center design, as well as the fact that on average, patients treated with FMT presented with worse clinical conditions than those treated with antibiotics, the study authors noted. They added that differences in several baseline characteristics between the groups still remained after matching.

On the other hand, a separate brief report from the U.S., published on Oct. 30 by the New England Journal of Medicine, cautioned that FMT-associated bloodstream infections can be deadly. The report described two patients in whom extended-spectrum beta-lactamase-producing Escherichia coli bacteremia occurred after they had received FMT capsules in two independent clinical trials. One patient died.

Both cases were linked to the same stool donor through genomic sequencing, and a total of 22 patients received FMT capsules generated from this donor. The two ill patients had risk factors for bacteremia: cirrhosis with hepatic encephalopathy in one and hematologic dysplasia treated by means of hematopoietic-cell transplantation in the other. Both patients received oral antibiotics near the time of FMT.

Currently, at least 10,000 FMTs are performed each year in the U.S., an accompanying editorial noted. While it is reasonable to test FMT in rigorous clinical trials, the intervention may carry risks that can only be identified after the fact, the editorialist wrote. “Improved screening of FMT donors and of the material to be transplanted will certainly reduce the risks of infections by known agents,” the editorial said. “… Despite its seemingly innocuous, if unpleasant, aspect and possibility to do it oneself at home, FMT carries a risk of infectious hazards that needs to be taken seriously.”