title: Retreatment tuberculosis in a South African community: the role of re-infection, HIV and antiretroviral treatment.
abstract: BACKGROUND
  Limited data exist on the impact of human immunodeficiency virus (HIV) or antiretroviral treatment (ART) on retreatment tuberculosis (TB).
  
  
  METHODS
  Retreatment TB episodes between 2001 and 2010 in a high HIV and TB burden community were linked to first-episode treatment  outcomes, HIV status and ART use. Genotypic analysis of Mycobacterium tuberculosis isolates distinguished re-infection from reactivation TB.
  
  
  RESULTS
  A total of 2027 TB episodes occurred in 1755 adults: 564 were retreatment cases. New patients who interrupted or failed initial treatment,  were HIV-positive or were not on ART more frequently developed retreatment TB (respectively P < 0.001, P = 0.01 and P = 0.02). Time intervals between successive diagnoses were shorter in patients who interrupted/failed treatment compared to those with favourable initial  treatment outcomes (P < 0.001), but did not vary by HIV status or ART use. Genotypic data were available for 40 successive diagnoses, of which 19 had matching M. tuberculosis strains. Matching strains were associated with HIV-negative status (P < 0.001), treatment  interruption/failure (P = 0.04) and shorter intervals between diagnoses (P = 0.02). HIV-positive patients and patients on ART were more likely to have non-matched strains (P = 0.01 and P = 0.03).
  
  
  CONCLUSIONS
  Among HIV-negative patients, retreatment TB was predominantly  due to reactivation following poor initial treatment outcomes. In HIV-positive patients re-infection TB was more common, particularly among those on ART.
authors.affiliation: Desmond Tutu HIV Centre, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa. keren.middelkoop@hiv-research.org.za
authors.forename: K
authors.initials: K
authors.lastname: Middelkoop
authors.forename: L-G
authors.initials: LG
authors.lastname: Bekker
authors.forename: E
authors.initials: E
authors.lastname: Shashkina
authors.forename: B
authors.initials: B
authors.lastname: Kreiswirth
authors.forename: R
authors.initials: R
authors.lastname: Wood
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use; D000995:Antitubercular Agents / Q000627:therapeutic use*; D005260:Female; D005838:Genotype; D018023:HIV Seronegativity; D006679:HIV Seropositivity / Q000188:drug therapy*; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D012008:Recurrence; D019233:Retreatment; D013019:South Africa / Q000453:epidemiology; D013997:Time Factors; D016896:Treatment Outcome; D014376:Tuberculosis / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents; D000995:Antitubercular Agents