A four-year nationwide molecular epidemiological study in Estonia: risk factors for tuberculosis transmission.

SETTING: Estonia has a high proportion of multidrug-resistant tuberculosis (MDR-TB). It is important to link molecular and epidemiological data to understand TB transmission patterns. OBJECTIVE: To use 24-locus variable numbers of tandem repeat (VNTR) typing and national TB registry data in Estonia from 2009 to 2012 to identify the distribution of drug resistance patterns, Mycobacterium tuberculosis isolate clustering as an index for recent transmission, socio-demographic and clinical characteristics associated with recent transmission, and the distribution of transmission between index and secondary cases. DESIGN: A retrospective nationwide cross-sectional study. RESULTS: Of 912 cases with isolate and patient information, 39.1% of isolates were from the Beijing lineage. Cluster analysis identified 87 clusters encompassing 69.1% of isolates. The largest cluster comprised 178 isolates from the Beijing lineage, of which 92.1% were MDR- or extensively drug-resistant TB (XDR-TB). Factors associated with recent transmission were polyresistant TB, MDR- and XDR-TB, human immunodeficiency virus positivity, Russian ethnicity, non-permanent living situation, alcohol abuse and detention. XDR-TB cases had the highest risk of recent transmission. The majority of transmission cases involved individuals aged 30-39 years. CONCLUSION: Recent TB transmission in Estonia is high and is particularly associated with MDR- and XDR-TB and the Beijing lineage

Drug Susceptibility Patterns in MDR-TB Patients:Challenges for Future Regimen Design. A Cross-Sectional Study

Globally, there is substantial concern regarding the challenges of treating complex drug resistance patterns in multidrug resistant tuberculosis cases. Utilising data from three different settings (Estonia, Latvia, Romania) we sought to contrast drug susceptibility profiles for multidrug resistant tuberculosis cases, highlight the difficulties in designing universal regimen, and inform future regimen selection. Demographic and microbiological surveillance data for multidrug resistant tuberculosis cases from 2004-13 were analysed. High levels of additional resistance to currently recommended second line drugs were seen in all settings, with extensive variability between countries. Accurate drug susceptibility testing and drug susceptibility testing data are vital to inform the development of comprehensive, flexible, multidrug resistant tuberculosis guidance