Surveillance of antituberculosis drug resistance in Switzerland 1995-1997:the central link

The purpose of the present paper is to investigate the usefulness of routin e notification of antituberculosis drug susceptibilities. In Switzerland, laboratories have to report susceptibilities to isoniazid, rifampicin, ethambutol, and pyrazinamide to the Federal Office of Public He alth. All clinical and laboratory information on every single tuberculosis case is routinely linked. proportions of drug resistance were calculated an d logistic regression was applied to evaluate the role of potential risk fa ctors. Eighty percent (1056) of all culture-positive tuberculosis cases reported b etween October 1995 and December 1997 were analysed. The strains of 66 (6.3 %) patients had resistances to at least one drug. Risk factors identified w ere previous antituberculosis treatment (adjusted odds ratio 7.3, 95% confi dence interval 3.9-13.6), male sex (1.4, 1.1-2.0), and age <65 yrs (1.5, 1. 0-2.3). Fourteen cases (1.3%), 13 of them foreign-born, were resistant to a t least isoniazid and rifampicin, Reporting of drug susceptibilities allows routine assessment of the proport ion of drug resistant tuberculosis and populations at risk. This proportion mas found to be small in Switzerland. Risk factors were previous treatment for tuberculosis, male srs, and age <65 yrs, Resistance to at least isonia zid and rifampicin was predominantly found in foreign-born patients.