An Outbreak of Tuberculosis Caused by Multiple-Drug-resistant Tubercle Bacilli among Patients with HIV Infection

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Abstract
▪ Objective: To evaluate a nosocomial outbreak of tuberculosis caused by multiple-drug-resistant bacilli among patients with tuberculosis and HIV infection. ▪ Design: A case-control study. ▪ Patients: Patients with HIV infection and culture-proven tuberculosis. ▪ Measurements: Patient characteristics, date of diagnoses of HIV infection and disease, date of diagnosis of tuberculosis, Mycobacterium tuberculosis susceptibility results, and medical center contact. ▪ Results: Sixty-two patients who had tuberculosis caused by multiple-drug-resistant bacilli (cases) and 55 patients who had tuberculosis caused by susceptible or single-drug-resistant bacilli (controls) were identified. Controls were more likely to be black (odds ratio, 0.4; 95% Cl, 0.2 to 0.9) or Haitian (odds ratio, 0.2; Cl, 0.1 to 0.6) compared with cases, who were more likely to be homosexual men (odds ratio, 2.9; Cl, 1.3 to 6.4). Forty-four cases (71%) had previous contact with an HIV clinic compared with 15 controls (27%) (P < 0.0001). Cases were more likely to have had AIDS (odds ratio, 7.7; Cl, 1.5 to 53.7), to have been hospitalized on an HIV ward (odds ratio, 8.3; Cl, 2.3 to 29.7), to have been seen in an HIV clinic (odds ratio, 7.8; Cl, 3.4 to 18.1), to have received intravenous therapy in an HIV clinic (odds ratio, 13.0; Cl, 4.6 to 37.0), or to have received inhalation pentamidine in an HIV clinic before a diagnosis of tuberculosis was made. Multiple logistic regression analysis showed that a diagnosis of AIDS (odds ratio, 11.2; Cl, 3.1 to 40.6) and HIV clinic visits (odds ratio, 13.0; Cl, 2.7 to 63.7) before a diagnosis of tuberculosis were significantly associated with tuberculosis caused by multiple-drug-resistant bacilli. Using susceptibility patterns and appointment dates, we found that 22 cases had previous contact with a person who had tuberculosis caused by multiple-drug-resistant bacilli in the HIV clinic. ▪ Conclusions: Nosocomial transmission of M. tuberculosis from other HIV-infected patients with tuberculosis caused by multiple-drug-resistant bacilli can occur. These findings have serious public health implications and demand strict adherence to acid-fast bacilli isolation precautions.