title: The influence of environmental exposure on the response to antimicrobial treatment in pulmonary Mycobacterial avium complex disease.
abstract: BACKGROUND
  Environmental exposure is a likely risk factor for the development of pulmonary Mycobacterium avium complex (MAC) disease. The influence of environmental exposure on the response to antimicrobial treatment and relapse is unknown.
  
  
  METHODS
  We recruited 72 patients with pulmonary MAC disease (male [female], 18 [54]; age, 61.7 ± 10.3 years) who initiated and completed standard three-drug regimens for more than 12 months between January 2007 and December 2011. The factors associated with sputum conversion, relapse and treatment success without relapse were retrospectively evaluated after adjustments for confounding predictors.
  
  
  RESULTS
  Fifty-two patients (72.2%) demonstrated sputum conversion, and 15 patients (28.8%) relapsed. A total of 37 patients (51.4%) demonstrated treatment success. Sputum conversion was associated with negative smears (odds ratio [OR], 3.89; 95% confidence interval [CI], 1.27-12.60; P = 0.02). A relapse occurred in patients with low soil exposure after the start of treatment less frequently than in patients with high soil exposure (7/42 [16.7%] vs. 8/10 [80.0%], P = 0.0003). Treatment success was associated with low soil exposure after the beginning of treatment (OR, 13.46; 95% CI, 3.24-93.43; P = 0.0001) and a negative smear (OR, 2.97; 95% CI, 1.02-9.13; P = 0.047).
  
  
  CONCLUSIONS
  Low soil exposure was independently associated with better microbiological outcomes in patients with pulmonary MAC disease after adjusting for confounding clinical, microbiological and radiographic findings.
authors.affiliation: Department of Respiratory Medicine, Kyoto, Japan. yutaka@kuhp.kyoto-u.ac.jp.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ito
authors.forename: Toyohiro
authors.initials: T
authors.lastname: Hirai
authors.forename: Kohei
authors.initials: K
authors.lastname: Fujita
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubo
authors.forename: Koichi
authors.initials: K
authors.lastname: Maekawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ichiyama
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
mesh_terms: D000368:Aged; D000995:Antitubercular Agents / Q000627:therapeutic use*; D017291:Clarithromycin / Q000627:therapeutic use; D004781:Environmental Exposure; D004977:Ethambutol / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015269:Mycobacterium avium Complex / Q000187:drug effects*; D015270:Mycobacterium avium-intracellulare Infection / Q000188:drug therapy* / Q000382:microbiology; D012008:Recurrence; D012189:Retrospective Studies; D012293:Rifampin / Q000627:therapeutic use; D012988:Soil Microbiology; D013183:Sputum / Q000382:microbiology; D016896:Treatment Outcome; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy* / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D004977:Ethambutol; D017291:Clarithromycin; D012293:Rifampin