A nationwide study of multidrug-resistant tuberculosis in Portugal 2014–2017 using epidemiological and molecular clustering analyses

Abstract

Background Increasing multidrug-resistant tuberculosis (MDR-TB) incidence is a major threat against TB eradication worldwide. We aim to conduct a detailed MDR-TB study in Portugal, an European country with endemic TB, combining genetic analysis and epidemiological data, in order to assess the efficiency of public health containment of MRD-TB in the country. Methods We used published MIRU-VNTR data, that we reanalysed using a phylogenetic analysis to better describe MDR-TB cases transmission occurring in Portugal from 2014 to 2017, further enriched with epidemiological data of these cases. Results We show an MDR-TB transmission scenario, where MDR strains likely arose and are transmitted within local chains. 63% of strains were clustered, suggesting high primary transmission (estimated as 50% using MIRU-VNTR data and 15% considering epidemiological links). These values are higher than those observed across Europe and even for sensitive strains in Portugal using similar methodologies. MDR-TB cases are associated with individuals born in Portugal and evolutionary analysis suggests a local evolution of strains. Consistently the sublineage LAM, the most common in sensitive strains in Europe, is the more frequent in Portugal in contrast with the remaining European MDR-TB picture where immigrant-associated Beijing strains are more common. Conclusions Despite efforts to track and contain MDR-TB strains in Portugal, their transmission patterns are still as uncontrolled as that of sensitive strains, stressing the need to reinforce surveillance and containment strategies. Electronic supplementary material The online version of this article (10.1186/s12879-019-4189-7) contains supplementary material, which is available to authorized users.

Using genomics to understand the origin and dispersion of multidrug and extensively drug resistant tuberculosis in Portugal

“…This high clustering rate reflects the underlying endemicity of the described clades in Portugal but, upon closer inspection of genomic clusters, the heterogenic composition of these clusters regarding drug resistance type and profiles also suggests the de novo emergence of MDR-TB in such clusters. Recent data obtained from MIRU-VNTR typing supports an epidemiological setting marked by uncontrolled MDR-TB transmission 47 . The situation is not novel, and the mostly represented MIRU-VNTR clusters therein identified have been previously described 5,48 .…”

Using Bayesian spatial models to map and to identify geographical hotspots of multidrug-resistant tuberculosis in Portugal between 2000 and 2016

“…Regarding hotspots of MDR-TB, 7 out of the 8 high-risk areas are located in the Lisbon metropolitan area. Previously identified MDR-TB genetic clusters revealed evidence of transmission of multidrug-resistant strains in this region 31 – 33 .…”

“…As previously described, 61% of the incidence of MDR-TB among previously treated patients resulted from MDR-TB transmissio 5 . In fact, genetic studies 31 – 33 suggested that a high percentage of these cases in Portugal were related with the transmission of two stable MDR-TB clusters.…”

Multidrug-Resistant Tuberculosis in Portugal: Patients’ Perception of the Challenges Faced during Treatment

“…All patients, however, reported that family members and other contacts had been called to the CDP for disease and infection screening. Recent studies conducted in Portugal, combining a strain genotyping analysis with epidemiological data from MDR-TB cases, have confirmed strong epidemiological links [19].…”