LTBI - MDR/XDR-TB cases - should all be treated?

<b>Aims and objectives:</b> Currently, there is still limitations of evidence to draw any recommendations on XDR-TB contacts preventive therapy. This study aimed to identify the patterns of the transmission of an XDR-TB case among household contacts from 2010 to present date. <b>Methods:</b> We review all household contacts (defined as persons living in the same household as the index case for at least 1 month). <b>Results:</b> The index case was a 34 years old male, drug‑addict, HIV positive, with XDR-TB in 2010&nbsp; (DST revealed resistance to H, R, Z, E, S, Am, Cm, Eto, Ofx; and sensitivity to PAS, Cs and Lzd). Initial screening of close contacts identified 4 adults and 3 children- all of them with confirmed LTBI, and none with active TB. No treatment for LTBI was prescribed. They were followed-up halfyearly for active disease. After a 2-year follow-up, 3 contacts developed active TB with a similar DST resistance pattern. WGS data confirmed the resistance profile and genetic relatedness of 2 of the cases and the index case (unavailable in the 3rd case). All contacts of the 3 secondary cases were traced and 9 close contacts were identified - 2 children and 7 adults.&nbsp; An adult case with active TB was detected (DST with sensitivity to all drugs) and 8 with LTBI. No treatment was prescribed for LTBI cases. Till now none of the close contacts with LTBI developed active TB. <b>Conclusions:</b> We present an XDR-TB index case with a family cluster of 3 active XDR-TB patients, 1 active sensitive TB patient and 12 LTBI cases. Since 25% of close contacts evolved to clinical disease, we may conclude that developing a treatment regimen for all LTBI cases of XDR-TB contacts would be advantageous. This was not recommended at the time, reflecting lack of available evidence of international guidelines.