Effect of broad- and narrow-spectrum antimicrobials on Clostridium difficile and microbial diversity in a model of the distal colon.
Vancomycin, metronidazole, and the bacteriocin lacticin 3147 are active against a wide range of bacterial species, including Clostridium difficile. We demonstrate that, in a human distal colon model, the addition of each of the three antimicrobials resulted in a significant decrease in numbers of C. difficile. However, their therapeutic use in the gastrointestinal tract may be compromised by their broad spectrum of activity, which would be expected to significantly impact on other members of the human gut microbiota. We used high-throughput pyrosequencing to compare the effect of each antimicrobial on the composition of the microbiota. All three treatments resulted in a decrease in the proportion of sequences assigned to the phyla Firmicutes and Bacteroidetes, with a corresponding increase in those assigned to members of the Proteobacteria. One possible means of avoiding such "collateral damage" would involve the application of a narrow-spectrum antimicrobial with specific anti-C. difficile activity. We tested this hypothesis using thuricin CD, a narrow-spectrum bacteriocin produced by Bacillus thuringiensis, which is active against C. difficile. The results demonstrated that this bacteriocin was equally effective at killing C. difficile in the distal colon model but had no significant impact on the composition of the microbiota. This offers the possibility of developing a targeted approach to eliminating C. difficile in the colon, without collateral damage.
Rea
Mary C
MC
Teagasc, Moorepark Food Research Centre, Fermoy, County Cork, Ireland.
Dobson
Alleson
A
O'Sullivan
Orla
O
Crispie
Fiona
F
Fouhy
Fiona
F
Cotter
Paul D
PD
Shanahan
Fergus
F
Kiely
Barry
B
Hill
Colin
C
Ross
R Paul
RP
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001430:Bacteriocins / Q000494:pharmacology*; D001483:Base Sequence; D016360:Clostridioides difficile / Q000187:drug effects*; D003106:Colon / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D006801:Humans; D054892:Metagenome / Q000187:drug effects* / Q000235:genetics; D008795:Metronidazole / Q000494:pharmacology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D014640:Vancomycin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; C082508:lacticin 481; D008795:Metronidazole; C059740:thuricin; D014640:Vancomycin