Tuberculosis, atypical mycobacterioses and human immunodeficiency virus: An overview

Tuberculosis (TB) and atypical mycobacterioses are among the most common opportunistic infections and the main causes of death in persons infected with human immunodeficiency virus (HIV) worldwide. As regards TB, the clinical and radiographical aspects are largely influenced by the stage of progression of HIV disease. Early in HIV infection, pulmonary findings resemble those of reactivation TB in immunocompetent hosts. On the contrary, in patients with more advanced immunosuppression, the presentation can be nonspecific, and the radiographical pattern is similar to primary TB infection. The treatment regimens for HIV-infected patients with TB are not different from those adopted for HIV-seronegative patients. However, the clinical and bacteriological response should be followed closely, and the therapy should be prolonged when the response is slow or suboptimal. Multidrug-resistant TB is increasingly recognized and presents difficult treatment problems. In such cases, therapy must be selected on the basis of the results of susceptibility studies. Disseminated infection with Mycobacterium avium complex (MAC) is a late event in the course of HIV disease. Clinical symptoms are not specific, being represented by fever, weight loss, night sweats, and diarrhoea; patients have a significantly reduced survival. Treatment regimens using multiple drug association are required. The optimal therapeutic regimen remains to be established, but a combination of a macrolide, ethambutol and rifabutin seems to be the most effective available choice. MAC prophylaxis should be considered for patients with advanced HIV disease (CD4 lymphocyte count less than 75 μL-1). Rifabutin has been the first drug to demonstrate effectiveness as a prophylactic agent in comparative trials. Subsequently, both clarithromycin and azithromycin have been proven to be more effective than rifabutin. The choice of the prophylactic regimen should take into account several individual factors, such as tolerability, potential for drug interactions, and dangers of resistance to the drug.