Fidaxomicin (Synonyms: Clostomicin B1, Lipiarmycin, OPT-80, PAR-101, Tiacumicin B)

Fidaxomicin is a macrocyclic antibiotic that inhibits RNA polymerase sigma subunit [1].

Antibiotics are a type of antimicrobial used in the treatment of bacterial infection. They can inhibit the growth of bacteria. Bacterial RNA polymerase mediates RNA synthesis.

Fidaxomicin is a narrow spectrum antibiotic that inhibits RNA polymerase sigma subunit. Fidaxomicin was a macrocyclic-lactone antibiotic produced by Actinomycete species. Fidaxomicin inhibited RNA polymerase in Clostridium difficile [1].

In patients infected with Clostridium difficile, fidaxomicin exhibited a higher clinical cure rate and a lower recurrence rate. In rats, fidaxomicin was safe by the intravenous route and exhibited LD50 value of 200 mg/kg. Fidaxomicin for the treament of Clostridium difficile infection (CDI) had entered Phase III trials [2]. In patients with CDI, fidaxomicin exhibited a lower reappearance of toxin in fecal filtrates and inhibited recurrence of CDI. Also, fidaxomicin preserved the intestinal microbiome during the treatment of CDI [3].

References:
[1].  Srivastava A, Talaue M, Liu S, et al. New target for inhibition of bacterial RNA polymerase: 'switch region'. Curr Opin Microbiol, 2011, 14(5): 532-543.
[2].  Poxton IR. Fidaxomicin: a new macrocyclic, RNA polymerase-inhibiting antibiotic for the treatment of Clostridium difficile infections. Future Microbiol, 2010, 5(4): 539-548.
[3].  Louie TJ, Cannon K, Byrne B, et al. Fidaxomicin preserves the intestinal microbiome during and after treatment of Clostridium difficile infection (CDI) and reduces both toxin reexpression and recurrence of CDI. Clin Infect Dis, 2012, 55 Suppl 2: S132-S142.