Drug-resistant tuberculosis in Castilla-León, Spain, 1996-2000

During 1996-2000, a regional anti-tuberculosis drug resistance survey was conducted in Castilla-León, Spain.

To determine the incidence of drug-resistant tuberculosis (TB) in newly treated human immunodeficiency virus (HIV) negative and HIV-positive TB patients.

Nine hundred and eighty-five Mycobacterium tuberculosis strains isolated from HIV-negative (926) and HIV-positive (59) patients were studied (one strain per patient). Univariate and multivariate analyses were used to determine the prevalence of drug resistance in high-risk groups.

Thirty-eight isolates (3.8%) showed resistance to one of the following drugs: streptomycin (S), isoniazid (H), rifampicin (R) or ethambutol (E). Of these, 36 (3.9%) were from HIV-negative and 2 (3.4%) from HIV-positive patients. The rate of drug resistance among HIV-negative patients was 1.2%, 2.0%, 0.3% and 0.8%, respectively, for S, H, R and E, and for HIV-positive patients it was 3.4%, 0%, 0% and 1.7%. Among the HIV-negative patients, monoresistance was observed in 32 (3.4%) strains and resistance to both H and R (multi-drug resistance) was detected in one.

The incidence of primary drug resistance in the surveyed area was low and increased resistance was not observed in the HIV-positive group (P = 0.99). Routine surveillance of drug resistance is recommended by the TB control programme in representative patient populations to optimise treatment regimens.