Effects of macrolides and ketolides on mycobacterial infections

New macrolides, such as clarithromycin and azithromycin, are active agents to Mycobacterium avium complex (MAC). Both clarithromycin and azithromycin are well-known for the ability to improve the prognosis of AIDS patients with disseminated MAC infection. However, the administration of monotherapy with a macrolide is usually associated with the emergence of drug resistance after a few months of use. Therefore, the recommended treatment for MAC infection involved the use of at least two antibiotics, which includes a macrolide in combination with rifabutin, moxifloxacin and/or ethambutol. When used as prophylactic therapy in AIDS patients, azithromycin is more convenient (1200 mg, once a week) than clarithromycin (500 mg, twice a day). Ketolides are a semi-synthetic derivative of erythromycin A, which differs from erythromycin A by substitution of a 3-keto group for L-cladinose. Telithromycin has a carbamate group linked to an imidazolium and pyridium nucleus at C11-C12. In mice model, both telithromycin and ABT-733 were active in vivo against MAC.