title: Distribution and clinical significance of Mycobacterium avium complex species isolated from respiratory specimens.
abstract: Mycobacterium avium complex (MAC) was originally composed of 2 species, M. avium and M. intracellulare. However, several new species closely related to M. intracellulare have recently been identified. In addition, M. avium has been further subdivided into 4 subspecies. The aim of this study was to determine the proportion of different MAC species recovered from respiratory specimens and to elucidate the clinical relevance of these species. Clinical isolates, from 219 patients, that had been initially identified as M. avium or M. intracellulare by non-sequencing methods were reidentified using multilocus sequence typing, and the clinical significance of the identified species was then investigated. Of 91 isolates originally identified as M. intracellulare, 75 (82%) were confirmed to be M. intracellulare, 8 (9%) isolates were identified as M. chimaera, and 4 (4%) isolates each were identified as "M. indicus pranii" and M. yongonense. The 128 isolates originally designated as M. avium were determined to be M. avium subsp. hominissuis. Of the 219 patients, 146 (67%) met the diagnostic criteria for MAC lung disease, and for each MAC species, the proportion of patients meeting these criteria was as follows: M. intracellulare (54/75, 72%), M. chimaera (3/8, 38%), "M. indicus pranii" (3/4, 75%), M. yongonense (2/4, 50%), and M. avium subsp. hominissuis (84/128, 66%). In summary, multilocus sequence typing of respiratory isolates initially identified as MAC revealed that, although most isolates were M. avium subsp. hominissuis or M. intracellulare, approximately 7% were newer MAC members, with clinical evidence supporting their potential pathogenicity for humans.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Su-Young
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Sun Hye
authors.initials: SH
authors.lastname: Shin
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Seong Mi
authors.initials: SM
authors.lastname: Moon
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Bumhee
authors.initials: B
authors.lastname: Yang
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Hojoong
authors.initials: H
authors.lastname: Kim
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: O Jung
authors.initials: OJ
authors.lastname: Kwon
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Hee Jae
authors.initials: HJ
authors.lastname: Huh
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Ki
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Lee
authors.affiliation: Department of Microbiology, Institute for Immunology and Immunological Diseases, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea. Electronic address: sjshin@yuhs.ac.
authors.forename: Sung Jae
authors.initials: SJ
authors.lastname: Shin
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. Electronic address: wjkoh@skku.edu.
authors.forename: Won-Jung
authors.initials: WJ
authors.lastname: Koh
mesh_terms: D000368:Aged; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000175:diagnosis* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D009162:Mycobacterium avium / Q000235:genetics* / Q000302:isolation & purification; D015269:Mycobacterium avium Complex / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D015270:Mycobacterium avium-intracellulare Infection / Q000175:diagnosis* / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial
keywords: Multilocus sequence typing; Mycobacterium avium; Mycobacterium avium complex; Mycobacterium intracellulare