Subspecies distribution of Mycobacterium abscessus in adult cystic fibrosis (CF) and non-CF patients

Abstract

Introduction: In 2015, of the 14,225 individuals in the United States CF Foundation Patient Registry who had a mycobacterial culture performed, 1,692 (11.9%) had a nontuberculous mycobacterium (NTM) isolated ≥1 time. M. abcessus (MABS) and its subspecies (subsp. abscessus , massiliense , and bolletii ) are the second most cultured NTM species in respiratory samples after M. avium complex. Methods: The National Jewish Health laboratory information system was queried for cultures positive with MABS for 2015 and 2016. Results: During 2015 to 2016, of a total of 297 patients with MABS, 15 patients were excluded from evaluation: 6 were 1 subspecies identified, and 1 patient9s isolate could not be subspeciated. Of the remaining 282 patients (241 Non-CF and 41 CF), 210 (74.5%) had MABS subsp. abcessus (abs), 58 (20.6%) subsp. massiliense (mass), and 14 (5.0%) subp. bolletti (boll). The distribution of the subspecies for 241 Non-CF versus 41 CF are as follows: abs-178 (73.9%) vs. abs-32 (78.0%); mass-52 (21.6%) vs. mass-6 (14.6%); boll-11 (4.6%) vs. boll-3 (7.3%). The female/male ratio for Non-CF vs. CF are as follows: abs 4.74 vs. 0,78; mass 1.6 vs. 2.0; boll 0.8 vs.2.0. The mean age for patients with abs is 64.5 years for Non-CF and 34.5 years for CF. Conclusion: The subspecies distribution is similar between the Non-CF and CF patients. The 30-year difference in the mean age between Non-CF and CF patients is not surprising. Female Non-CF patients are 4 times more likely to harbor MABS isolates versus males. This is in stark contrast to the CF patients, where the sex distribution is not different.