Isabel Portugal

Genotypic analysis of Mycobacterium tuberculosis isolates from a Lisbon hospital in Portugal

Portugal has one of the highest tuberculosis notification rates of the European Union with Lisbon Health Region having an incidence rate well above the national average. The present study analyses the transmission, drug susceptibility and characteristics of a study population from a Central Lisbons Hospital. One hundred and thirty -two Mycobacterium tuberculosis clinical isolates were previously tested for drug susceptibility to first -line drugs. The multidrug (MDR) resistance rate was found to be 3.0%, while 13.6% of the isolates were resistant to one or more first -line drugs. HIV serology was available for 98 patients, 26 (26.5%) were positive. Genotyping was performed by MIRU -VNTR and 53 (40.2%) out of the 132 isolates were found to be distributed through 17 MIRU -VNTR clusters of two or more isolates. Lisboa strains accounted for 25.8% of all strains. We conclude that transmission of resistant and susceptible Mycobacterium tuberculosis strains is occurring, with special concern for Lisboa strains.

Molecular epidemiology of Mycobacterium tuberculosis in Lisbon

We conducted a molecular epidemiology study of Mycobacterium tuberculosis strains isolated from patients in Lisbon hospitals. We used restriction fragment length polymorphism (RFLP) to detect Lisbon family strains and to determine the genetic diversity of Mycobacterium tuberculosis strains isolated in Lisbon, through identification of the most important risk factors of tuberculosis transmission analysis, with the insertion sequence IS6110 as a probe to fingerprint isolates of Mycobacterium tuberculosis. 64.8% of the 290 Mycobacterium tuberculosis isolates were grouped in clusters. This figure was 60.7% if we excluded strains with five or fewer IS6110 copies. Multidrug-resistance was observed in 4.1% of the strains and they were all in clusters. Forty-five (18.2%) strains were included in the Lisbon family. Considering the relatively high percentage of strains in cluster detected in this study, we believe that active transmission is still taking place in Lisbon. Moreover, clusters of Lisbon strains represent the predominant strains circulating in Lisbon and are still related to drug resistance although presenting a lower percentage than that observed in previous studies.