Disseminated Nontuberculous Mycobacteria in HIV-Infected Patients

Abstract

Nontuberculous mycobacteria are ubiquitous in the environment and are increasingly implicated in human diseases worldwide. Currently, there are more than 150 species of Mycobacterium and it is likely that more will be discovered. The rapid increase in identified species in recent years is due to improved culturing techniques and more precise differentiations of species. The application of highly active antiretroviral therapy for the treatment of HIV disease dramatically reduced rates of all opportunistic infections including nontuberculous mycobacteria. Despite this decline, nontuberculous mycobacterium remains one of the most commonly encountered opportunistic infections in AIDS patients. Disseminated nontuberculous mycobacteria infections are seen exclusively among immunocompromised hosts, including those with AID. Disseminated disease is most commonly seen in association with profound immunosuppression. In HIV infected patients, dissemination does not typically occur unless the CD-4+ T-lymphocyte count is below 50/uL. Structural lung disease, such as chronic obstructive pulmonary disease, silicosis, pneumoconiosis or prior TB infection, predisposes to pulmonary infection. Nodular bronchiectasis is very strongly associated with nontuberculous mycobacteria infections. Disseminated Mycobacterium avium complex disease was one of the first opportunistic infections recognized as part of the syndrome of AIDS .Interest in disseminated Mycobacterium avium and nontuberculous mycobacteria infections increased as a result of the HIV epidemic, and therapeutic strategies to treat and prevent these diseases must be focused. Prevention and treatment regimens were lifelong because cure of nontuberculous mycobacteria was not achievable in AIDS patients with profound immune suppression.