Mode of action |
Fusidic acid forms a stable complex with an elongation factor (EF-G) involved in translocation and with guanosine triphosphate (GTP), which provides energy for the translocation process. One round of translocation occurs, with hydrolysis of GTP, but the fusidic acid–EF-G–GDP complex cannot dissociate from the ribosome, thereby blocking further chain elongation and leaving peptidyl-tRNA in the P site.
Although protein synthesis in Gram-negative bacilli–and, indeed, mammalian cells–is susceptible to fusidic acid, the antibiotic penetrates poorly into these cells and the spectrum of action is virtually restricted to Gram-positive bacteria, notably staphylococci. |