RESUMO
We describe a microevolutionary event of a prevalent strain of Mycobacterium tuberculosis that caused two outbreaks in San Francisco. During the second outbreak, a direct variable repeat was lost. We discuss the mechanisms of this change and the implications of analyzing multiple genetic loci in this context.
Assuntos
Genes Bacterianos , Variação Genética , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/genética , Sequências Repetitivas de Ácido Nucleico/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , DNA Bacteriano/análise , Surtos de Doenças , Evolução Molecular , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Prevalência , São Francisco , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/microbiologiaRESUMO
BACKGROUND: Treatment of patients with multidrug-resistant tuberculosis requires prolonged therapy, often involving long hospital stays. Despite intensive and costly therapy, cure rates are relatively low. METHODS: We reviewed the outcomes for all patients with multidrug-resistant tuberculosis treated in San Francisco, California, during 1982-2000 and identified billing charges for patients treated during 1995-2000. Mycobacterium tuberculosis isolates were genotyped by IS6110-based restriction fragment-length polymorphism analysis. RESULTS: Forty-eight cases were identified with resistance to a median of 3 drugs (range, 2-9 drugs). The median age of the patients was 49.5 years (range, 22-78 years); 36 (75%) of 48 patients were foreign born, 11 (23%) were human immunodeficiency virus (HIV) seropositive, and 45 (94%) had pulmonary tuberculosis. Thirty-two (97%) of the 33 HIV-seronegative patients were cured, with only 1 relapse occurring 5 years after treatment. All 11 HIV-seropositive patients died during observation. Twenty-one patients (44%) required hospitalization, with a median duration of stay of 14 days (range, 3-74 days). The estimated inpatient and outpatient aggregate cost for the 11 patients treated after 1994 was $519,928, with a median cost of $27,752 per patient. No secondary cases of multidrug-resistant tuberculosis were identified through population-based genotyping. CONCLUSIONS: Treatment of multidrug-resistant tuberculosis in HIV-seronegative patients largely on an outpatient basis was feasible and was associated with high cure rates and lower cost than in other published studies. Patients with underlying HIV infection had very poor outcomes.