• Poster 254: Frequency of Isolation of M. avium complex (MAC) from Marrow in Patients Suspected of Disseminated MAC (DMAC) but with Negative Blood Cultures (Authored by R.R. Macgregor, D.C. Perlman, R. Murphy, C. Inderlied, L. Bermudez, J. Andersen, E. Bassily, S. Koletar, D. Peterson, R. Hafner, and The ACTG 341 Study Team. AIDS Clin. Trials Group, Bethesda, MD)
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• Poster 255: Impact of Combination Antiretroviral Therapy on the Risk of Tuberculosis among Persons with HIV (Authored by E. Girardi, G. Antonucci, P. Vanacore, M. Libanore, I. Errante, A. Matteelli, G. Ippolito, and GISTA Study Group. IRCCS Spallanzani, Rome, Italy)
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Poster 254

Although Mycobacterium avium Complex (MAC) infections have become dramatically less common in the HAART era, this pathogen is still of concern in those with low T-cell counts.

This protocol looks at the diagnostic value of MAC culture from different sites in patients with symptoms clinically suggestive of MAC infection. Importantly, 80% of patients clinically suggestive of MAC had no positive culture. Of those with positive cultures, the bone marrow was the most sensitive: only 1/4 patients with a positive bone marrow culture had a positive blood culture. Cultures from non-sterile sites had little prognostic value. Additional analysis demonstrated that those with positive cultures had lower measures of immune responsiveness.

In those with suspected MAC infection, treatment should not be dependent on positive culture results. Bone marrow culture may have the highest yield of various culture sites.

Poster 255

In many patient populations tuberculosis remains a significant risk. This survey from Italy assessed the risk of developing tuberculosis in HIV-infected patients. 1,360 patients were followed for an average of over two years' follow-up. Not surprisingly, the strongest risk factors for developing tuberculosis were a positive TB skin test, and low T-cell count.

HIV treatment dramatically reduced the risk of developing active tuberculosis: the relative risk for those on a two drug regimen was 18% of those on no treatment, and less than 10% for those on three drugs (relative risk adjusted for T cells and skin test status).

Even in those at high risk for development of TB, treatment of concurrent HIV infection can dramatically reduce the incidence of active TB.