Mycobacterium avium complex MAC infection

Prevention of disseminated Mycobacterium avium complex (MAC) infections 1,200 mg taken once weekly. 

The incidence of disseminated Mycobacterium avium complex (MAC) infection has increased dramatically with the AIDS epidemic. Treatment regimens for patients with a positive culture for MAC from a sterile site should include two or more drugs, including clarithromycin. Prophylaxis against disseminated MAC should be considered for patients with a CD4 cell count of less than 50 X 10 /1 (5). In a randomized, open trial in 37 patients with HIV-associated disseminated MAC infection, treatment with clarithromycin -I- ethambutol produced more rapid resolution of bacteremia, and was more effective at sterilization of blood cultures after 16 weeks than azithromycin -I- ethambutol (6). 

Freedberg, K. A., Cohen, C. J., and Barber, T. W. (1997). Prophylaxis for disseminated Mycobacterium avium complex (MAC) infection in patients with AIDS A cost-effectiveness analysis. J. Acquir. Immune Defic. Syndr. Hum. Retroviral. 15, 275-282. 

A 35-year old Caucasian man with AIDS and multiple opportunistic infections, including Mycobacterium kansasii and Mycobacterium avium complex (MAC) disease developed moderate to severe primary sensorineural hearing loss after 4—5 months of therapy with oral azithromycin 500 mg/day. Other medications included ethambutol, isoniazid, rifabutin, ciprofloxacin, co-trimoxazole, fluconazole, zidovudine (later switched to stavudine), lamivudine, indinavir, methadone, mod-ified-release oral morphine, pseudoephedrine, diphenhydramine, megestrol acetate, trazodone, sorbitol, salbutamol by metered-dose inhaler and nebulizer, ipratropium, and oral morphine solution as needed. Significant improvement of the hearing impairment was documented 3 weeks after drug withdrawal. 

Organisms of the Mycobacterium avium complex (MAC) commonly cause disseminated bacterial infection among patients with AIDS. There is evidence that immunoprophylaxis against MAC infection may be possible. A heat-killed Mycobacterium vaccae vaccine was given in a three-dose schedule to 12 HIV-infected adults with CD4 cell counts below 300 x 10 /1 (107). The vaccine was well tolerated and produced detectable immunological responses in 3 of 11 subjects who completed the trial. 

Surveillance data indicate that the incidence of certain OIs in HIV-infected persons in the United States continues to change. The three major OIs—Pneumocystis carinii pneumonia (PCP), Mycobacterium avium complex (MAC) disease, and cytomegalovirus (CMV) retinitis—all have decreased in incidence. Potent antiretroviral reg-... 

Anterior Segment Glucocorticoids also have been implicated in cataract formation. If vision is reduced, cataract surgery may be necessary. Rifabutin, if used in conjunction with clarithromycin or fluconazole for treatment of Mycobacterium avium complex (MAC) opportunistic infections in AIDS, is associated with an iridocyclitis and even hypopyon. This will resolve with glucocorticoids or by stopping the medication. 

Infection with the human immunodeficiency virus (HIV) may produce isolated lymphadenopathy resulting from direct infection by the virus or from secondary infection (Radin 1995 Tarantino et al. 2003). Mesenteric lymphadenopathy in patients with HIV is far more likely to result from an opportunistic infection or even an underlying malignancy than to be caused by direct HIV infection. In this case, the lymph nodes may be enlarged but rarely massive. On the contrary, in HIV positive patients with a CD4 cell count of 50/mL or less, Mycobacterium avium complex (MAC) is the main cause of massive mesenteric lymphadenopathy. In HIV patients with mesenteric lymph nodes, in particular if forming a conglomerate mass, MAC infection should always be considered (Koh et al. 2003 Tarantino et al. 2003) (Fig. 2.9). 

MAC Mycobacterium avium complex (typical bacterial infection in HIV or immunocompromised patients) maint maintenance MAO/MAOI monoamine... 

---