<i>Notes from the Field</i>: Potential Outbreak of Extrapulmonary <i>Mycobacterium abscessus</i> subspecies <i>massiliense</i> Infections from Stem Cell Treatment Clinics in Mexico — Arizona and Colorado, 2022

Mycobacterium abscessus is an intrinsically drug-resistant, rapidly growing, nontuberculous mycobacterium; extrapulmonary infections have been reported in association with medical tourism (1).During November-December 2022, two Colorado hospitals (hospitals A and B) treated patient A, a Colorado woman aged 30-39 years, for M. abscessus meningitis.In October 2022, she had received intrathecal donor embryonic stem cell injections in Baja California, Mexico to treat multiple sclerosis and subsequently experienced headaches and fevers, consistent with meningitis.Her cerebrospinal fluid revealed neutrophilic pleocytosis and grew M. abscessus in culture at hospital A. Hospital A's physicians consulted hospital B's infectious diseases (ID) physicians to co-manage this patient (2).In spring 2023, hospital B's ID physicians identified two additional patients with M. abscessus infections acquired after receiving stem cell injections performed at different clinics in Mexico.The first of these, patient B, an Arizona man aged 60-69 years, developed a right elbow osteoarticular infection after receiving donor embryonic stem cell injections for psoriatic arthritis at a Baja California, Mexico clinic different from the one that treated patient A, in April 2022.The second, patient C, a Colorado man aged 60-69 years, developed bilateral knee infections after receiving donor embryonic stem cell injections in both knees for osteoarthritis at a clinic in Guadalajara, Mexico, in October 2022.