TABLE 1.

Examples of current and future antibiotics useful for Clostridium difficile infections

Antibiotic	Target	Putative resistance mechanism(s)	Reference(s)
Metronidazole	Bacterial DNA, causing DNA breakage and destabilization of the DNA helix	Alterations in some metabolic pathways, biofilm formation	13, 42, 43, 49, 50, 52, 53
Vancomycin	d-Ala-d-Ala subunit of the precursor UDP-N-acetylmuramyl pentapeptide of peptidoglycan	Mutations in peptidoglycan biosynthesis-required proteins, biofilm formation	33
Fidaxomicin	Bacterial RNA polymerase	Mutations in rpoB	33
Rifamycins	β-Subunit of DNA-dependent RNA polymerase	Mutations in rpoB	44
Ramoplanin	Inhibiting peptidoglycan biosynthesis	Not reported
Fusidic acid	Inhibiting protein synthesis by binding elongation factor G on the ribosome	Mutations in fusA	69
Nitazoxanide	Pyruvate, ferredoxin oxidoreductase	Not reported
Tigecycline	30S ribosomal subunit	Not reported
Cadazolid	Bacterial protein synthesis and DNA synthesis	Not reported
Surotomycin	Disrupting the membrane potential	Not reported
Ridinilazole (SMT19969)	Inhibits DNA synthesis	Not reported
CRS3123 (REP3123)	Methionyl-tRNA synthetase (MetRS) inhibitor	Not reported