title: Treatment of Mycobacterium avium complex infection: do the results of in vitro susceptibility tests predict therapeutic outcome in humans?
abstract: The ability of various in vitro methods of antibiotic susceptibility testing to predict therapeutic outcome in patients infected with Mycobacterium avium complex (MAC) was evaluated. Pretreatment bloodstream MAC isolates from 38 patients with AIDS, previously treated in a randomized fashion with either ethambutol, rifampin, or clofazimine, were tested by three conventional methods using broth or agar, as well as by cocultivation with macrophages. The results obtained with each method were compared with the quantitatively determined bacteriologic response to the administration of the single agent in humans. None of the conventional in vitro susceptibility methods was predictive of therapeutic outcome, while the results of cocultivation with macrophages were of moderate predictive value. The positive predictive value of a response in humans based on a response in macrophages (defined by > or = to 1.0 log reduction in baseline colony counts after 5 days of treatment) was 74%. The negative predictive value was 82%.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Santa Clara Valley Medical Center, San Jose, CA 95128, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Sison
authors.forename: Y
authors.initials: Y
authors.lastname: Yao
authors.forename: C A
authors.initials: CA
authors.lastname: Kemper
authors.forename: J R
authors.initials: JR
authors.lastname: Hamilton
authors.forename: E
authors.initials: E
authors.lastname: Brummer
authors.forename: D A
authors.initials: DA
authors.lastname: Stevens
authors.forename: S C
authors.initials: SC
authors.lastname: Deresinski
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000150:complications / Q000188:drug therapy; D000904:Antibiotics, Antitubercular / Q000627:therapeutic use; D000995:Antitubercular Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000150:complications / Q000188:drug therapy; D002991:Clofazimine / Q000627:therapeutic use; D004977:Ethambutol / Q000627:therapeutic use; D006801:Humans; D066298:In Vitro Techniques; D008264:Macrophages / Q000187:drug effects / Q000382:microbiology; D008826:Microbial Sensitivity Tests / Q000379:methods*; D015269:Mycobacterium avium Complex / Q000187:drug effects / Q000302:isolation & purification; D015270:Mycobacterium avium-intracellulare Infection / Q000150:complications / Q000188:drug therapy*; D012293:Rifampin / Q000627:therapeutic use
chemical_list: D000904:Antibiotics, Antitubercular; D000995:Antitubercular Agents; D004977:Ethambutol; D002991:Clofazimine; D012293:Rifampin