4. Section of Preventive Medicine

Abstract

have been associated with outbreaks and multidrug resistance. We performed a retrospective thirteen-year surveillance study (1993 of the available isolates from 332 cases of tuberculosis tested of an immigrant patient from Senegal with pulmonary tuberculosis. The strain was not drug resistant and besides six close contact persons that were infected no secondary cases of this strain were low and there is no evidence of transmission or higher virulence. Molecular epidemiology studies have revealed a genotype of M. tuberculosis strains that seem to possess selective advantages compared with other strains, have increased virulence and are sometimes associated with multidrug resistance [1,2]. This it is widespread around the world. The fact that this family of strains is widespread and, in some situations, associated with multidrug resistance has led to concern that these strains may be spreading the study of trends over time is of great interest. However, report