 notes from the field potential outbreak of extrapulmonary mycobacterium abscessus subspecies massiliense infections from stem cell treatment clinics in mexico arizona and colorado 2022 in 2022 three patients developed extrapulmonary m abscessus infections after receiving embryonic stem cell injections in three cities in mexico through whole genome sequencing isolates from two patients were identified as m abscessus subspecies massiliense of a single clone distinct from known dominant circulating clones indicating a common infected source associated with the injections is possible 