Mycobacterial infections, drugs used

The advent of multidrug resistant strains of Mycobacterium tuberculosis (MDR-TB) has led to increased fears of untreatable infections by serious pathogens. Rifampicin, streptomycin and, occasionally, the quinolones are drugs used in the treatment of mycobacterial infections and resistance to those agents is as described previously. There... 

Mycobacterial infections - Recommended as the primary agent for the treatment of disseminated MAC. Use in combination with other antimycobacterial drugs that have shown in vitro activity against MAC. 

Ciprofloxacin and levofloxacin are no longer recommended for the treatment of gonococcal infection in the USA as resistance is now common. However, both drugs are effective in treating chlamydial urethritis or cervicitis. Ciprofloxacin, levofloxacin, or moxifloxacin is occasionally used for treatment of tuberculosis and atypical mycobacterial infections. These agents may be suitable for eradication of meningococci from carriers or for prophylaxis of infection in neutropenic patients. 

Ethambutol Inhibits mycobacterial arabinosyl transferases, which are involved in the polymerization reaction of arabinoglycan an essential component of the mycobacterial cell wall Bacteriostatic activity against susceptible mycobacteria Given as four-drug initial combination therapy for tuberculosis until drug sensitivities are known also used for atypical mycobacterial infections Oral t mixed clearance (half-life 4 h) dose must be reduced in renal failure Toxicity Retrobulbar neuritis... 

Rifampin, usually 600 mg/d (10 mg/kg/d) orally, is administered together with isoniazid, ethambutol, or another antituberculous drug in order to prevent emergence of drug-resistant mycobacteria. In some short-course therapies, 600 mg of rifampin is given twice weekly. Rifampin 600 mg daily or twice weekly for 6 months also is effective in some atypical mycobacterial infections and in leprosy when used together with a sulfone. Rifampin is an alternative to isoniazid prophylaxis for patients who are unable to take isoniazid or who have had close contact with a case of active tuberculosis caused by an isoniazid-resistant, rifampin-susceptible strain. 

Summary of drugs used to treat mycobacterial infections. 

Rifabutin (t 36 h) has similar activity and adverse reactions, and is used for prophylaxis of Mycobacterium avium infection in patients with AIDS, and for treatment of tuberculous and nontuberculous mycobacterial infection in combination with other drugs. 

Thus, though mycobacterial infections are difficult to treat under even the best of circumstances using currently available drugs, novel antibiotics targeting the biosynthesis of the unique mycobacterial cell wall structures show promise for clinical development. Further characterization of the enzymes involved in the biosynthesis of cell wall structures will facilitate the development of such antibiotics. Furthermore, studies of the cell wall biosynthetic pathways will likely uncover new potential targets for drug design efforts. 

Rifabutin may be used in the prophylaxis of M. avium complex infections in immunocompromised patients and in the treatment, with other drugs, of pulmonary tuberculosis and non-tuberculous mycobacterial infections. 

The use of these drugs in the treatment and prevention of mycobacterial infections is described in... 

Clofazimine is used in combination with a host of other drugs for the cure and treatment of leprosy and infections caused hy Mycobacterium avium particularly in AIDS patients. It gets bound to mycobacterial DNA and also interferes with growth. It is proved to be a bactericidal agent and may even take upto almost 50 days before exerting its killing effect . It shows oral-systemic bioavailability to approximately 50%. In the course of maintenance therapy the elimination half-life stands at 70 days. 

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