Faecal microbiota transplant for recurrent Clostridium difficile infection using long-term frozen stool is effective: clinical efficacy and bacterial viability data.
BACKGROUND
Faecal microbial transplant (FMT) for recurrent Clostridium difficile infection (rCDI) is greatly facilitated by frozen stool banks. However, the effect of frozen storage of stool for greater than 2 months on the viability of stool bacteria is unknown and the efficacy of FMT is not clear.


OBJECTIVE
To evaluate the viability of bacteria in stool frozen for up to 6 months, and the clinical efficacy of FMT with stool frozen for 2-10 months, for the treatment of rCDI.


METHODS
Viability of six representative groups of faecal bacteria after 2 and 6 months of storage at -80 °C, in normal saline (NS) or 10% glycerol were assessed by culture on plate media. The clinical outcomes of 16 consecutive patients with rCDI treated with aliquots of stool frozen in 10% glycerol and stored for 2-10 months were also examined.


RESULTS
Viability at both 2 and 6 months was similar to baseline, in specimens stored in 10% glycerol and at 2 months in stool stored in NS, but was reduced by >1 log at 6 months for Aerobes (P < 0.01), total Coliforms (P < 0.01) and Lactobacilli (P < 0.01) in NS. Using stool frozen for 2-10 months in 10% glycerol, the cure rate for rCDI was 88% with one FMT and 100% after repeat FMT in those who relapsed.


CONCLUSIONS
Stool for faecal microbial transplant to treat rCDI can be safely stored frozen in 10% glycerol for at least 6 months without loss of clinical efficacy or viability in the six bacterial groups tested.
IBD Service, Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, SA, Australia.|Department of Gastroenterology, The Queen Elizabeth Hospital, Woodville, SA, Australia.|School of Medicine, Faculty of Health Sciences, University of Adelaide, SA, Australia.
S P
SP
Costello
CSIRO Food and Nutrition Flagship, Adelaide, SA, Australia.
M A
MA
Conlon
CSIRO Food and Nutrition Flagship, Adelaide, SA, Australia.
M S
MS
Vuaran
Department of Gastroenterology, The Queen Elizabeth Hospital, Woodville, SA, Australia.|School of Medicine, Faculty of Health Sciences, University of Adelaide, SA, Australia.
I C
IC
Roberts-Thomson
IBD Service, Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, SA, Australia.|School of Medicine, Faculty of Health Sciences, University of Adelaide, SA, Australia.
J M
JM
Andrews
D000328:Adult; D000368:Aged; D016360:Clostridioides difficile / Q000472:pathogenicity / Q000502:physiology; D003015:Clostridium Infections / Q000382:microbiology / Q000628:therapy*; D000069467:Fecal Microbiota Transplantation; D005243:Feces / Q000382:microbiology*; D005260:Female; D005615:Freezing; D006801:Humans; D008297:Male; D050296:Microbial Viability; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D055502:Secondary Prevention / Q000379:methods*; D013048:Specimen Handling / Q000379:methods*; D016896:Treatment Outcome