Biochem/physiol Actions

Fidaxomicin is a first-in-class macrocyclic antibacterial agent for gram positive bacteria treatment, notably Clostridium difficile infections. Fidaxomicin produces its antibacterial effects by inhibiting bacterial RNA polymerase at transcription initiation. Furthermore, Fidaxomicin is an inhibitor of bacterial transcription. Fidaxomicin acts at an earlier step in the transcription initiation pathway. Specifically, Fidaxomicin binds to the DNA template-RNA polymerase complex and prevents the initial separation of DNA strands, which precedes messenger RNA synthesis by inhibiting the s subunit. Fidaxomicin′s unique target site may explain its limited spectrum of antimicrobial activity because s subunits differ among bacterial species.

Therapeutic dosage of fidaxomicin is found have less bactericidal effect on the bowel microbiota and reduces the recurrence of C. difficile infection.

Other Notes

Chemical name: [(2R,3S,4S,5S,6R)-6-[[(3E,5E,8S,9Z,11S,12R,13E,15E,18S)-12-[(2R,3S,4R,5S)-3,4-Dihydroxy-6,6-dimethyl-5-(2-methylpropanoyloxy)oxan-2-yl]oxy-11-ethyl-8-hydroxy-18-[(1R)-1-hydroxyethyl]-9,13,15-trimethyl-2-oxo-1-oxacyclooctadeca-3,5,9,13,15-pentaen-3-yl]methoxy]-4-hydroxy-5-methoxy-2-methyloxan-3-yl] 3,5-dichloro-2-ethyl-4,6-dihydroxybenzoate