[Drug-resistance in Mycobacterium tuberculosis in Castilla y León, Spain, 2001-2005: third collaborative study].

Introduction: During 2001-2005, a regional anti-tuberculosis drug resistance survey was conducted in Castilla y León, Spain, in newly treated HIV negative tuberculosis (TB) patients.

Methods: A total of 918 Mycobacterium tuberculosis strains were studied (one strain per patient) from six hospitals corresponding to 46.7% of the total population of Castilla y León, using the proportion method on solid medium.