title: The significance of Mycobacterium abscessus subspecies abscessus isolation during Mycobacterium avium complex lung disease therapy.
abstract: BACKGROUND
  Isolation of Mycobacterium abscessus subspecies abscessus (MAA) is common during Mycobacterium avium complex (MAC) lung disease therapy, but there is limited information about the clinical significance of the MAA isolates.
  
  
  METHODS
  We identified 53 of 180 patients (29%) treated for MAC lung disease who had isolation of MAA during MAC lung disease therapy. Patients were divided into those without (group 1) and those with (group 2) MAA lung disease.
  
  
  RESULTS
  There were no significant demographic differences between patients with and without MAA isolation or between groups 1 and 2. Group 1 and 2 patients had similar total sputum cultures obtained (P = .7; 95% CI, -13.4 to 8.6) and length of follow-up (P = .8; 95% CI, -21.5 to 16.1). Group 2 patients had significantly more total positive cultures for MAA (mean±SD, 15.0 ± 11.1 vs 1.2 ± 0.4; P < .0001; 95% CI, -17.7 to -9.9), were significantly more likely to develop new or enlarging cavitary lesions while on MAC therapy (P > .0001), and were significantly more likely to meet all three American Thoracic Society diagnostic criteria for nontuberculous mycobacterial disease (21 of 21 [100%] vs 0 of 32 [0%]; P < .0001) compared with group 1 patients. Group 1 patients were significantly more likely to have single, positive MAA cultures than group 2 patients (25 of 31 vs 0 of 21; P < .0001).
  
  
  CONCLUSIONS
  Microbiologic and clinical follow-up after completion of MAC lung disease therapy is required to determine the significance of MAA isolated during MAC lung disease therapy. Single MAA isolates are not likely to be clinically significant.
authors.affiliation: Departments of Medicine, University of Texas Health Science Center, Tyler, TX. Electronic address: david.griffith@uthct.edu.
authors.forename: David E
authors.initials: DE
authors.lastname: Griffith
authors.affiliation: Departments of Medicine, University of Texas Health Science Center, Tyler, TX.
authors.forename: Julie V
authors.initials: JV
authors.lastname: Philley
authors.affiliation: Microbiology, the University of Texas Health Science Center, Tyler, TX.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Brown-Elliott
authors.affiliation: Departments of Medicine, University of Texas Health Science Center, Tyler, TX.
authors.forename: Jeana L
authors.initials: JL
authors.lastname: Benwill
authors.affiliation: Microbiology, the University of Texas Health Science Center, Tyler, TX.
authors.forename: Sara
authors.initials: S
authors.lastname: Shepherd
authors.affiliation: Microbiology, the University of Texas Health Science Center, Tyler, TX.
authors.forename: Deanna
authors.initials: D
authors.lastname: York
authors.affiliation: Departments of Medicine, University of Texas Health Science Center, Tyler, TX; Microbiology, the University of Texas Health Science Center, Tyler, TX.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Wallace
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D015270:Mycobacterium avium-intracellulare Infection / Q000188:drug therapy* / Q000382:microbiology*; D009170:Nontuberculous Mycobacteria / Q000145:classification / Q000302:isolation & purification*