[M. tuberculosis complex drug resistance in Navarre: differences between the local and immigrant populations]

Tuberculosis is an important public health problem, whose epidemiology in our country has changed in recent years due to the increase in the immigrant population. The aim of this article is to evaluate the frequency of resistance to the four principal antitubercular drugs in both the local and immigrant populations.

A study was made of the antibiograms of 457 isolations of Mycobacterium tuberculosis carried out in the Hospital of Navarre in 2000-2007. The antibiograms were processed using the BACTEC460TB system.

Twenty six point three percent of the strains corresponded to immigrants, with a significant increase occurring over the period. The frequencies of resistances to the different antitubercular drugs in the local and immigrant populations respectively were: to at least one 5.6% vs 20.8% (p <0.001); to isoniazid 4.5% vs 14.2% (p <0.001); to streptomycin 2.4% vs 12.6% (p <0.001); to rifampicin 0.9% vs 5% (p <0.05); to ethambutol 0.3% vs 2.5% (p <0.05); and multiresistance 0.3% vs 2.5% (p <0.05).

There are significant differences between local and immigrant populations in the pattern of resistances of the strains isolated. The immigrant population, due to the high frequency with which resistance is shown to isoniazid, must be treated initially with a pattern of four drugs until the result of the biogram is available.