Low serum concentrations of antituberculous drugs, which suggest malabsorption, are common among patients with advanced HIV who also have tuberculosis but can be overcome with higher doses. Therapeutic drug monitoring may be an effective tool to optimize therapy, but needs further study.

An alternative regimen for the treatment of latent tuberculosis infection is 2 months of rifampin and pyrazinamide, but some patients have died of hepatitis associated with this therapy. One hundred fourteen patients received rifampin/pyrazinamide in Wake County, North Carolina, between December 1999 and May 2002; 60.5% of these patients were homeless, and at least 17% drank alcohol to excess. Seventy-seven patients (67.5%) completed a full 2-month course. Nine patients had a history of viral hepatitis or chronic liver disease. Four of 114 (3.5%; 95% confidence interval, 1.0-8.7%) patients developed hepatitis on therapy, and another two had symptoms consistent with hepatitis but did not report for laboratory testing (total confirmed plus suspected hepatitis rate 5.3%; 95% confidence interval, 2.0-11.1%). No patient who developed hepatitis had a history of viral hepatitis or liver disease, and none had been previously treated with isoniazid. No patients died or were hospitalized due to drug side effects. Rifampin/pyrazinamide was associated with a significantly higher rate of hepatitis than previously described with isoniazid therapy for latent tuberculosis but resulted in a high completion rate. The rifampin/pyrazinamide regimen for latent tuberculosis infection may be useful for high-risk, traditionally nonadherent patient groups, but careful monitoring for toxicity is required.

We investigated a cluster of patients with tuberculosis (TB) in North Carolina and determined the extent of transmission of 1 strain of Mycobacterium tuberculosis. A retrospective cohort study was conducted. Homeless shelter attendance and medical records for 1999 and 2000 were reviewed. The period of exposure to M. tuberculosis was determined, and shelter residents were offered TB screening. DNA fingerprinting was performed on 72 M. tuberculosis isolates. In addition to the initial index cluster of 9 patients, another 16 patients were identified. Isolates of M. tuberculosis from all 25 patients shared a matching DNA fingerprint pattern. All but 1 patient was male, 22 (88%) were African American, and 14 (56%) were human immunodeficiency virus-infected. An epidemiological link to a single shelter was identified for all but 1 patient. Earlier recognition of this shelter as a site of M. tuberculosis transmission could have been facilitated through innovative approaches to contact investigation and through genetic typing of isolates.