title: Clinical significance of the differentiation between Mycobacterium avium and Mycobacterium intracellulare in M avium complex lung disease.
abstract: BACKGROUND
  Mycobacterium avium and Mycobacterium intracellulare are grouped together as the M avium complex; however, little is known about the clinical impact of this species differentiation. This study compared the clinical features and prognoses of patients with M avium and M intracellulare lung disease.
  
  
  METHODS
  From 2000 to 2009, 590 patients were given a new diagnosis of M avium complex lung disease; 323 (55%) had M avium lung disease, and 267 (45%) had M intracellulare lung disease.
  
  
  RESULTS
  Compared with the patients with M avium lung disease, the patients with M intracellulare lung disease were more likely to have the following characteristics: older age (64 vs 59 years, P = .002), a lower BMI (19.5 kg/m² vs 20.6 kg/m², P < .001), respiratory symptoms such as cough (84% vs 74%, P = .005), a history of previous treatment for TB (51% vs 31%, P < .001), the fibrocavitary form of the disease (26% vs 13%, P < .001), smear-positive sputum (56% vs 38%, P < .001), antibiotic therapy during the 24 months of follow-up (58% vs 42%, P < .001), and an unfavorable microbiologic response after combination antibiotic treatment (56% vs 74%, P = .001).
  
  
  CONCLUSIONS
  Patients with M intracellulare lung disease exhibited a more severe presentation and had a worse prognosis than patients with M avium lung disease in terms of disease progression and treatment response. Therefore, species differentiation between M avium and M intracellulare may have prognostic and therapeutic implications.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Seoul, South Korea. Electronic address: wjkoh@skku.edu.
authors.forename: Won-Jung
authors.initials: WJ
authors.lastname: Koh
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Seoul, South Korea.
authors.forename: Byeong-Ho
authors.initials: BH
authors.lastname: Jeong
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Seoul, South Korea.
authors.forename: Kyeongman
authors.initials: K
authors.lastname: Jeon
authors.affiliation: Department of Laboratory Medicine, Seoul, South Korea.
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Lee
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Kyung Soo
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Biostatistics Team, Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, South Korea.
authors.forename: Sook Young
authors.initials: SY
authors.lastname: Woo
authors.affiliation: Department of Microbiology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Sung Jae
authors.initials: SJ
authors.lastname: Shin
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Seoul, South Korea.
authors.forename: O Jung
authors.initials: OJ
authors.lastname: Kwon
mesh_terms: D000367:Age Factors; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003371:Cough / Q000453:epidemiology; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D006801:Humans; D008168:Lung / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D009162:Mycobacterium avium / Q000302:isolation & purification* / Q000502:physiology; D015269:Mycobacterium avium Complex / Q000302:isolation & purification* / Q000502:physiology; D015270:Mycobacterium avium-intracellulare Infection / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology*; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents