Tuberculosis Multidrogo resistente en la era final de la Tuberculosis / Multidrug-Resistant Tuberculosis in the End Tuberculosis Era / Multidrug-Resistant Tuberculosis in the End Tuberculosis Era

RESUMEN La tuberculosis multidrogo resistente (TB-MDR) surgió poco después de la introducción de rifampicina en la década de 1960, cuando la resistencia a la isoniazida ya había emergido a mediados de la década de 1950. Sin estos dos medicamentos, la tuberculosis es muy difícil y costosa de tratar, con tasas inaceptablemente altas de fracaso del tratamiento, muertes, pérdidas durante el seguimiento y ningún tratamiento preventivo conocido. La atención global se centró por primera vez en la TB-MDR en la década de 1990 cuando se reportaron brotes hospitalarios con altas tasas de letalidad en muchos países. Los datos de prevalencia para TB-MDR a escala global estaban por primera vez disponibles en 1997. En 2016, 4,1% de aproximadamente 10,4 millones de pacientes nuevos más el 19% de un millón de pacientes tratados previamente, hacían un aproximado de 600 000 personas que desarrollaron TB-MDR o resistencia a la rifampicina; y 250 000 murieron dicho año. Hace diez años, menos del 5% de ellos fueron diagnosticados e iniciaron el tratamiento, aumentando a aproximadamente en 21,6% en 2016, dejando un amplio margen para mejorar. Durante ese mismo período de tiempo, se han fomentado avances para combatir la TB-MDR, incluidos los avances en diagnóstico, terapéutica y atención; descentralizando la atención en el paciente junto con el apoyo social; crecientes mejoras en la prevención de la transmisión; uso cada vez mayor de tratamientos antirretrovirales de alta efectividad; comunicación, abogacía y movilización social; liderazgo y actualización del enfoque de las políticas. Teniendo en cuenta las tendencias epidemiológicas a largo plazo, todos estos factores junto con el financiamiento del Fondo Mundial y otros donantes importantes, sugieren que podemos estar a punto de acelerar la disminución de la morbilidad y mortalidad por TB-MDR. La pobreza extrema, que permite el incremento de la tuberculosis ha disminuido en aproximadamente mil millones de personas en los últimos 25 años. Lo que se necesita ahora es voluntad política por parte de los gobiernos nacionales para aplicar estos avances con diligencia y buscar una mayor reducción de pobreza, empujando las tendencias epidemiológicas más allá del punto de inflexión hacia una pendiente descendente. Todo esto se puede acelerar con un mayor apoyo para la ciencia que conduzca a un mejor diagnóstico, tratamiento y una vacuna efectiva para sostener y acelerar las reducciones reportadas hasta el momento.

ABSTRACT Multidrug-resistant (MDR) tuberculosis (TB) emerged shortly after introduction of rifamycins in the 1960s; isoniazid resistance had already emerged by the mid-1950s. Without these two drugs, tuberculosis is very difficult and costly to treat, with unacceptably high rates of treatment failure, death, loss to follow-up, and no known preventive treatment. Global attention first focused on MDR TB in the early 1990s when nosocomial outbreaks with high case fatality rates were reported in many countries. Prevalence data for MDR TB on a global scale first became available in 1997. In 2016, about 4.1% of estimated ~10.4 million new TB patients plus 19% of ~1 million previously treated patients, that is ~600,000 people develop MDR TB or rifampicin resistant TB; 250,000 die annually. Ten years ago, <5% of them were diagnosed and enrolled on treatment, increasing to about 21.6% in 2016, leaving much room for improvement. Over that same period of time, momentum has been building to combat MDR TB, including advances in diagnostics, therapeutics, and care; decentralizing patient-centered care coupled with social support; growing improvements in prevention of transmission; increasing use of highly effective antiretroviral treatment; communications, advocacy, and social mobilization; leadership and updated policy guidance. Taking into account long-term epidemiological trends, all of these factors coupled with funding from the Global Fund and other major donors, suggest we may be on the verge of accelerating declines in MDR TB morbidity and mortality. Extreme poverty, which allows tuberculosis to flourish, has actually decreased by about one billion people over the past 25 years. What is needed now is political will on the part of national governments to apply these advances diligently and further reductions in poverty, pushing epidemiological trends past the inflection point to the downward slope. All these can be accelerated with increased support for science leading to better diagnosis, treatment and an effective vaccine to sustain and accelerate the meager declines reported thus far.

ABSTRACT Multidrug-resistant (MDR) tuberculosis (TB) emerged shortly after introduction of rifamycins in the 1960s; isoniazid resistance had already emerged by the mid-1950s. Without these two drugs, tuberculosis is very difficult and costly to treat, with unacceptably high rates of treatment failure, death, loss to follow-up, and no known preventive treatment. Global attention first focused on MDR TB in the early 1990s when nosocomial outbreaks with high case fatality rates were reported in many countries. Prevalence data for MDR TB on a global scale first became available in 1997. In 2016, about 4.1% of estimated ~10.4 million new TB patients plus 19% of ~1 million previously treated patients, that is ~600,000 people develop MDR TB or rifampicin resistant TB; 250,000 die annually. Ten years ago, <5% of them were diagnosed and enrolled on treatment, increasing to about 21.6% in 2016, leaving much room for improvement. Over that same period of time, momentum has been building to combat MDR TB, including advances in diagnostics, therapeutics, and care; decentralizing patient-centered care coupled with social support; growing improvements in prevention of transmission; increasing use of highly effective antiretroviral treatment; communications, advocacy, and social mobilization; leadership and updated policy guidance. Taking into account long-term epidemiological trends, all of these factors coupled with funding from the Global Fund and other major donors, suggest we may be on the verge of accelerating declines in MDR TB morbidity and mortality. Extreme poverty, which allows tuberculosis to flourish, has actually decreased by about one billion people over the past 25 years. What is needed now is political will on the part of national governments to apply these advances diligently and further reductions in poverty, pushing epidemiological trends past the inflection point to the downward slope. All these can be accelerated with increased support for science leading to better diagnosis, treatment and an effective vaccine to sustain and accelerate the meager declines reported thus far.

Eliminación de la tuberculosis, un vecindario por vez / Eliminating tuberculosis one neighborhood at a time

OBJETIVOS: Evaluamos una estrategia para la prevención de la tuberculosis en las comunidades más afectadas por esta enfermedad. MÉTODOS: En 1996, trazamos un mapa de los casos de tuberculosis notificados (1985-1995) y de las personas con reacción positiva a la prueba de la tuberculina (1993-1995) en el condado de Smith, Texas, Estados Unidos de América. Definimos los dos conglomerados de mayor tamaño y densidad, identificando los dos vecindarios con mayor incidencia (180 manzanas y 3 153 residentes). Tras una preparación intensiva de la comunidad, personal sanitario capacitado ofreció a todos los residentes, de vivienda en vivienda, la posibilidad de hacerse la prueba de la tuberculina, a menos que estuviera contraindicado. A las personas con resultados positivos en esta prueba se las acompañó a un consultorio móvil para realizarles ahí radiografías, una evaluación clínica y, según fuera pertinente, proceder con el tratamiento preventivo con isoniazida. Para evaluar las repercusiones a largo plazo, trazamos un mapa de todos los casos de tuberculosis que se registraron en el condado de Smith durante el período equivalente después del proyecto. RESULTADOS: De las 2 258 personas que cumplían los requisitos para participar, 1 291 (57,1%) se sometieron a la prueba de la tuberculina, 229 (17,7%) presentaron resultados positivos en dicha prueba y 147 fueron tratadas. De 1996 al 2006, no se registró ningún caso de tuberculosis en ninguno de los vecindarios del proyecto, a diferencia de lo ocurrido en el decenio anterior a la intervención y en el resto del condado de Smith, donde aparecieron continuamente casos de tuberculosis. CONCLUSIONES: Dirigirse a los vecindarios con una incidencia alta para realizar el tamizaje activo en la comunidad y aplicar tratamiento preventivo con isoniazida puede acelerar la eliminación de la tuberculosis en los Estados Unidos.

OBJECTIVES: We evaluated a strategy for preventing tuberculosis (TB) in communities most affected by it. METHODS: In 1996, we mapped reported TB cases (1985-1995) and positive tuberculin skin test (TST) reactors (1993-1995) in Smith County, Texas. We delineated the 2 largest, densest clusters, identifying 2 highest-incidence neighborhoods (180 square blocks, 3153 residents). After extensive community preparation, trained health care workers went door-to-door offering TST to all residents unless contraindicated. TST-positive individuals were escorted to a mobile clinic for radiography, clinical evaluation, and isoniazid preventive treatment (IPT) as indicated. To assess long-term impact, we mapped all TB cases in Smith County during the equivalent time period after the project. RESULTS: Of 2258 eligible individuals, 1291 (57.1%) were tested, 229 (17.7%) were TST positive, and 147 were treated. From 1996 to 2006, there were no TB cases in either project neighborhood, in contrast with the preintervention decade and the continued occurrence of TB in the rest of Smith County. CONCLUSIONS: Targeting high-incidence neighborhoods for active, community-based screening and IPT may hasten TB elimination in the United States.