This study examined whether adding levofloxacin to a standard four-drug regimen improved the 8-week culture response and compared effectiveness of 9 versus 6 months of intermittent therapy for human immunodeficiency virus -related pansusceptible pulmonary tuberculosis. Patients were randomized to receive either four or five drugs, the fifth being levofloxacin. Patients who completed induction therapy were randomized to complete 9 versus 6 months of intermittent therapy with isoniazid and rifampin. In the randomized induction phase, 97.3% of patients in the four-drug group and 95.8% in the five-drug group had sputum culture conversion at 8 weeks (P Å 1.00). In the continuation phase, one patient (2%) assigned to 9 months and two patients (3.9%) assigned to 6 months of therapy had treatment failure/relapse (P Å 1.00). In conclusion, this study showed that levofloxacin added no benefit to a highly effective, largely intermittent, four-drug induction regimen. Both 9 and 6 months of intermittent therapy were associated with low treatment failure/relapse rates.

In New York City, a large proportion of new tuberculosis cases has been caused by 1 drug-susceptible strain (called C strain) of Mycobacterium tuberculosis. Between 1991 and 1994, among >600 tuberculosis patients consecutively identified in four large hospitals in the city, 54 with C strain, 69 with non-C cluster pattern strains, and 42 with noncluster pattern strains were studied. Susceptibility to reactive nitrogen intermediates (RNI) of selected isolates was compared. In a case-control analysis, 51% of patients with C strain, 28% with non-C cluster strains (P < .05), and 14% with noncluster strains (P < .01) were found to be injection drug users. C strain but not 13 other unrelated isolates were resistant to RNI. Injection drug use may provide a selective pressure for an RNI-resistant tubercle bacillus to emerge, which may give the organism a biologic advantage and explain the widespread dissemination of C strain M. tuberculosis within the city.

In this report from New York City, HIV-negative patients with multidrug-resistant tuberculosis, contrary to previous reports, responded well to appropriate chemotherapy, both clinically and microbiologically.