Trends in Mycobacterium tuberculosis Transmission During a 10-year Period (2006-2016) in the Northwest of Iran by MIRU-VNTR Molecular Typing

Background: Mycobacterium tuberculosis is one of the biggest health challenges all over the world. The Caucasian region is one of the places with a high prevalence of drug-resistant M. tuberculosis. Objectives: In this study, we aimed to investigate the trends in M. tuberculosis transmission during a 10-year period in the northwest of Iran. Methods: We collected 166 M. tuberculosis isolates from 2005 to 2006 and 119 M. tuberculosis isolates from 2015 to 2016 and subjected them to MIRU-VNTR and ETR-VNTR typing by a polymerase chain reaction and compared them by phylogenic tools. Results: In the 2006 isolates, 104 different patterns were observed including 75 unique patterns and 91 isolates were clustered in 29 different clusters. In the 2016 isolates, 98 different patterns were observed with 86 unique patterns and 33 isolates were clustered in 12 different clusters. One cluster had a shared member from the 2006 and 2016 isolates, indicating the transmission of a single isolate during these years. The minimum estimate for the tuberculosis proportion, which is due to the recent transmission of tuberculosis, was 36.7% for the 2006 isolates and 17.6% for the 2016 isolates. Conclusions: In spite of the reduced number of tuberculosis patients, the isolates were more resistant and had a close relationship with worldwide strains. Cross-border immigration for treatment from Republic of Azerbaijan had significant participation in the recent transmission of tuberculosis in this region. In conclusion, the strict control of patients commuting and developing new tuberculosis clinics inside Republic of Azerbaijan can play a key role in the control of tuberculosis transmission in the northwest of Iran.