Study design and flowchart of study participants.

Grey boxes show the cases of TB that have been not included in the case-control study. *HAIN Life Science, based on acid nucleic amplification technology. ^† Samples were re-tested after data on the initial 106 cases and 318 controls had been already collected. ** Overall 79 cases were eventually detected in the prevalence survey. Of them only 52 were included in the present case control study. The remaining 27 were not included because identified after the fieldwork was completed. ^§The 54 cases excluded were classified as follows: M. intracellulare (N. 21), Non Mycobacteria Type 1 (N. 9), M. scrofulaceum (N. 3), M. asiaticum (N. 2), M. goodie (N. 1), M. gordonae (N. 1), M. parafinicum (N. 1), M. peregrinum (N. 1), M. terrae II (N. 1). The remaining 14 strains were classified as unidentified Mycobacteria species.