Objectives: To determine the frequency of resistant Mycobacterium tuberculosis and the risk factors associated with resistance in the province of Castellón (Spain).
Material and methods: This prospective study of M. tuberculosis sensitivity applied Canetti's method of proportions to all strains isolated in Castellón (n = 532) from January 1992 through December 1998 (7 years); 461 cases were new.
Results: The overall frequency of resistant strains was 4.7% (25/532), of which 3.9% (18/461) were instances of primary resistance and 11.1% (7/63) were of secondary resistance. Three percent were resistant to isoniazid, 1.87% to rifampicin, 1.87% to streptomycin and 0.56% to ethambutol. Multiple drug resistance was found in 0.2% (1/461) of the new cases and 1.1% (6/532) overall. The presence of resistant M. tuberculosis was associated with a history of antituberculous treatment (OR = 3.14; p = 0.017) and the presence of one or more risk factors for tuberculosis (OR = 3.32; p = 0.066).
Conclusions: The overall rates of resistant M. tuberculosis and multiple drug resistance are low in the province of Castellón; however resistance is associated with higher mortality such that controlling some preventable risk factors might reduce the frequency of resistance.