Resistance to First-Line Antituberculosis Drugs in Spain, 2010–2011. RETUBES Study

IntroductionThe magnitude of current resistance to antituberculosis drugs in Spain is unknown. The objective of this study is to describe resistance to first-line antituberculosis drugs and determine the associated factors.MethodsProspective multicenter study of adult tuberculosis patients with positive Mycobacterium tuberculosis culture and antibiogram including first-line drugs in 32 hospitals and one out-patient center of the Spanish Health System between 2010 and 2011.ResultsA total of 519 patients, 342 Spanish nationals and 177 (34.1%) foreigners were studied. Drug resistance was found in 48 (9.2%), of which 35 (6.7%) were isoniazid-resistant. There were 10 (1.9%) multiresistant cases and no strain was extremely resistant. Initial isoniazid resistance was detected in 28 of the 487 (5.7%) antituberulosis-naïve patients, most of whom were foreigners (p<.01). Acquired resistance was seen in 7 (22.6%) previously treated cases. Multiresistance was initial in 6 cases (1.2%) and acquired in another 4 (12.9%). Factors associated with initial isoniazid resistance were immigrant status and group cohabitation (OR=2.3; 95% CI: 0.98–5.67 and OR=2.2; 95% CI: 1.05–7.07 respectively). The factor associated with acquired resistance to isoniazid was age below 50 years (p=.03).ConclusionsThe rate of initial isoniazid resistance is greater than estimated, probably due to the increase in immigration during recent years, suggesting that systematic national monitoring is required. Immigrants and those who cohabit in groups have a higher risk of isoniazid resistance.

ResumenIntroducciónLa magnitud de la resistencia actual a fármacos antituberculosos en España es desconocida. El objetivo del estudio es describir la resistencia a fármacos antituberculosos de primera línea y determinar sus factores asociados.MétodosEstudio prospectivo multicéntrico de pacientes tuberculosos adultos con aislamiento de Mycobacterium tuberculosis y antibiograma de fármacos de primera línea en 32 hospitales y un centro extrahospitalario del sistema sanitario nacional durante los años 2010 y 2011.ResultadosSe estudió a 519 pacientes, 342 españoles y 177 (34,1%) extranjeros, 48 de ellos (9,2%) con resistencia a cualquier fármaco, de los que 35 (6,7%) eran resistentes a isoniacida. Hubo 10 casos multirresistentes (1,9%) y ninguno extremadamente resistente. Se detectó resistencia inicial a isoniacida en 28 de los 487 (5,7%) pacientes sin antecedentes de tratamiento antituberculoso previo, afectando más a los extranjeros (p < 0,01), y resistencia adquirida en 7 (22,6%) casos previamente tratados. La multirresistencia fue inicial en 6 casos (1,2%) y adquirida en otros 4 (12,9%). Los factores asociados a tener resistencia inicial a isoniacida fueron ser inmigrante y la convivencia en grupo (OR = 2,3; IC del 95%, 0,98–5,67, y OR = 2,2; IC del 95%, 1,05–7,07, respectivamente). El factor asociado a la existencia de resistencia adquirida a isoniacida fue la edad inferior a 50 años (p = 0,03).ConclusionesLa tasa de resistencia inicial a isoniacida es superior a la estimada, probablemente debida al aumento de la inmigración durante los últimos años, lo que aconseja su vigilancia nacional sistemática. Los individuos inmigrantes y los que conviven en grupo tienen mayor riesgo de tener resistencia a isoniacida.