Standard genotyping overestimates transmission of Mycobacterium tuberculosis among immigrants in a low-incidence country. Journal of Clinical Microbiology
Stucki et al. for the Swiss HIV Cohort and Molecular Epidemiology of Tuberculosis Study Groups reanalyzed transmission clusters previously defined by mycobacterial interspersed repetitive-unit–variable-number tandem-repeat (MIRU-VNTR) typing by using whole-genome sequencing (WGS) to assess the transmission of M. tuberculosis among Swiss and foreign-born tuberculosis (TB) patients. Of 520 TB patients, 18 of 35 transmission clusters identified by standard molecular genotyping (spoligotyping and MIRU-VNTR typing) were refuted by WGS. There was a striking difference between transmission clusters involving Swiss-born patients and clusters involving foreign-born patients.
The study-results suggest that transmission of M. tuberculosis is generally overestimated in countries with a low incidence of TB such as Switzerland. The authors recommend the use of WGS for more accurate identification of recent transmission of M. tuberculosis among immigrants.