Randomised clinical trial: a 12-strain bacterial mixture versus faecal microbiota transplantation versus vancomycin for recurrent Clostridioides difficile infections.

BACKGROUND: A defined bacterial mixture could be a safer alternative to faecal microbiota transplantation (FMT). AIMS: To compare the efficacy of a 12-strain mixture termed rectal bacteriotherapy with either FMT or vancomycin for recurrent Clostridioides difficile infection (CDI) in an open-label 3-arm randomised controlled trial. METHODS: We screened all individuals positive for C difficile from May 2017 to March 2019. Persons with laboratory-confirmed recurrent CDI were included. Before FMT and rectal bacteriotherapy, we pre-treated with vancomycin for 7-14 days. Rectal bacteriotherapy was applied by enema on three consecutive days and FMT by enema once with possible repetition for two to three infusions within 14 days. The vancomycin group was treated for 14 days with additional five weeks of tapering for multiple recurrences. The primary outcome was clinical cure within 90 days. A secondary outcome was 180-day all-cause mortality. RESULTS: Participants in the FMT group (n = 34) were cured more often than participants receiving vancomycin (n = 31), 76% vs 45% (OR 3.9 (1.4-11.4), P < 0.01) or rectal bacteriotherapy (n = 31), 76% vs 52% (OR 3.0 (1.1-8.8), P = 0.04). Rectal bacteriotherapy and vancomycin performed similarly (P = 0.61). The mortality rate was 6% in the FMT group, 13% in the bacteriotherapy group and 23% in the vancomycin group. FMT tended to reduce mortality compared with vancomycin, OR 0.2 (0.04-1.12), P = 0.07. CONCLUSIONS: Rectal bacteriotherapy appears as effective as vancomycin but less effective than 1-3 FMTs. FMT by enema with 1-3 infusions is superior to vancomycin for treating recurrent C difficile infections and might reduce mortality.

Mutational change of CTX-M-15 to CTX-M-127 resulting in mecillinam resistant Escherichia coli during pivmecillinam treatment of a patient.

Pivmecillinam (amdinocillin pivoxil) is the recommended first-choice antibiotic used to treat urinary tract infections (UTIs) in Denmark. The frequency of mutation to mecillinam (MEC) resistance is described as high in vitro; however, treatment of UTI has a good clinical response and prevalence of mecillinam resistance in Escherichia coli remains low despite many years of use. We describe occurrence of in vivo mecillinam resistance in a clinical isolate of ESBL-producing E. coli following pivmecillinam treatment. The identified phenotypic differences in the mecillinam resistant isolate compared with the original mecillinam susceptible isolate were a full-length LPS with O-antigen (O25), mecillinam resistance and a lower MIC for ceftazidime. Regarding genotype, the resistant isolate differed with a mutation in blaCTX-M-15 to blaCTX-M-127 , loss of a part of a plasmid and a genomic island, respectively, and insertion of a transposase in wbbL, causing the rough phenotype. The observed mecillinam resistance is expected to be caused by the mutation in blaCTX-M-15 with additional contribute from the serotype shift. We continue to recommend the use of pivmecillinam as first-line treatment for UTI.