RESUMO
OBJECTIVE: To determine the role of Mycobacterium bovis in active pediatric tuberculosis (TB) in a United States-Mexico border region. METHOD: We reviewed all new cases of pediatric (<15 years old) TB presenting to San Diego hospitals and clinics from 1980 to 1997. Patients were categorized by age, ethnicity, country of origin, culture results, and disease manifestations. Case definitions were similar to those used by the Centers for Disease Control and Prevention. M bovis was distinguished from Mycobacterium tuberculosis by standard biochemical tests. RESULTS: The median age of the 563 identified patients was 4.1 years old. The yearly incidence began rising in 1989 and peaked in the mid-1990s. Hispanics constituted 78.9% of the patients, but they were less likely to be foreign-born (21.6%) than were black children and Asian/Pacific Islanders. Overall, M bovis caused 10.8% of all TB during this period. Of the 180 patients with positive culture results, however, M bovis accounted for 33.9% and M tuberculosis 66. 1%. This high percentage of M bovis infections was largely attributable to its contribution to extrapulmonary TB (55.2% of all culture-positive specimens). M bovis patients were also even more likely to be Hispanic (90.2%), to present with extrapulmonary disease (95.1%), and to be older than 12 months (96.8%). CONCLUSION: These data demonstrate the dramatic impact of this underappreciated cause of zoonotic TB on US children at the Mexican border and underscore the need for cross-collaboration to enforce existing Mexican pasteurization laws.
Assuntos
Mycobacterium bovis/isolamento & purificação , Tuberculose/epidemiologia , Tuberculose/microbiologia , Adolescente , Distribuição por Idade , California/epidemiologia , Criança , Pré-Escolar , Humanos , Incidência , Lactente , Recém-Nascido , México/epidemiologia , Mycobacterium tuberculosis/isolamento & purificação , Prevalência , Fatores de Risco , Tuberculose/etnologia , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/etnologia , Tuberculose Pulmonar/microbiologia , Zoonoses/epidemiologia , Zoonoses/microbiologiaRESUMO
Decreasing susceptibility to zidovudine (ZDV) has been described in persons infected with human immunodeficiency virus (HIV) type 1 who are receiving ZDV therapy. However, the clinical significance of decreased ZDV susceptibility remains unclear. In this study, HIV isolates obtained from children with symptomatic HIV infection treated with ZDV were monitored for their susceptibility to the antiretroviral agent and correlated with disease progression. Using a peripheral blood mononuclear cell-based assay to measure ZDV susceptibility, we evaluated HIV isolates from 19 children (mean age, 6.8 years; range, 5 months to 12 years) during ZDV therapy for susceptibility to ZDV. Of the 19 children studied, 10 continued to have susceptible HIV strains during ZDV treatment, and 9 acquired resistant viruses. All eight isolates from children without previous exposure to ZDV were initially susceptible. After a median of 11 months of ZDV therapy, three (38%) of these eight children had acquired resistant HIV strains (defined as ZDV susceptibility > or = 10 mumol/L). Children with resistant strains had worse clinical outcomes than children whose viruses remained susceptible, as determined by a 50% decline in absolute CD4+ cell counts after 1 year of treatment, failure to thrive, or death. Children with resistant viruses who were given alternative antiretroviral therapy frequently responded to the new treatment with improved growth and stabilization of their HIV-related disease. These data suggest that, in HIV-infected children, ZDV-resistant HIV strains are associated with diminished drug efficacy and more rapid disease progression.
Assuntos
Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , HIV-1/efeitos dos fármacos , Zidovudina/antagonistas & inibidores , Síndrome da Imunodeficiência Adquirida/imunologia , Síndrome da Imunodeficiência Adquirida/microbiologia , Administração Oral , Linfócitos T CD4-Positivos/efeitos dos fármacos , Criança , Pré-Escolar , Resistência Microbiana a Medicamentos , Feminino , Proteína do Núcleo p24 do HIV/sangue , HIV-1/isolamento & purificação , Humanos , Lactente , Contagem de Leucócitos/efeitos dos fármacos , Masculino , Testes de Sensibilidade Microbiana/métodos , Fatores de Tempo , Resultado do Tratamento , Zidovudina/administração & dosagemRESUMO
We have presented 73 patients (48 adults and 25 children) with microbiologically documented M. bovis infections identified over the 12-year period from 1980 through 1991. Epidemiologic investigation of these patients revealed that the majority (80%) were of Hispanic origin. The non-Hispanic patients either had traveled extensively outside the United States, were born in the United States during its endemic period or in other countries with endemic bovine tuberculosis, or were exposed to a close relative with a positive PPD and known exposure to M. bovis. For Hispanic patients, the presence of reactivation disease in adults and primary disease in children indicate that this mycobacterium remains endemic in Mexican beef and dairy herds, a position supported by United States monitoring of Mexican cattle transferred across the border. Our review of the historical and contemporary efforts to eradicate this animal and human pathogen from the livestock industry in the United States and abroad shows that the implementation of similar methods could be effective in Mexico. The detailed presentations of selected patients and summaries of the clinical manifestations in the remainder of our 73 patients reveal striking similarities to historical accounts and to more contemporary studies of reactivated disease in England. Although M. bovis infections are still expressed predominantly in extrapulmonary sites (cervical and mesenteric nodes, the peritoneum, and the GU tract), as many as 50% of adult patients will present only with pulmonary disease. Underlying immunosuppressive disorders were particularly prominent in adults with extrapulmonary disease. For example, HIV positive patients accounted for 12 of 48 adults and 1 adolescent patient in our series. Overall, M. bovis infections accounted for almost 3% of all tuberculous disease reported in San Diego County during the study period. The intrinsic resistance of M. bovis to PZA could threaten the response of patients with bovine tuberculosis to the short-course chemotherapeutic regimens now recommended by the CDC and the American Thoracic Society. We strongly recommend continued surveillance for this forgotten pathogen because the importation of Mexican cattle, the migration of Hispanic immigrants from border areas to the United States interior, and the persistence of extrapulmonary disease in immunocompetent and HIV-infected United States citizens assure its persistence in this country.