> The outbreak involved 13 people across four households in Kansas City and spanned 1 year. While a majority of the seven adults identified were born outside the U.S. in a country that had experienced a multidrug-resistant TB outbreak with the same genotype in 2007-2009, most of the six children were U.S.-born, noted Elizabeth Groenweghe, MPH, of the Unified Government Public Health Department in Kansas City, and colleagues in the Morbidity and Mortality Weekly Report.

So it's either been a latent infection in someone in the first household or they traveled to their home country and brought it back, or something.. it's likely the local health department knows the exact lineage and route it took but they avoid publishing the full details for obvious reasons in this climate.