title: Molecular epidemiology of tuberculosis in Victoria, Australia, reveals low level of transmission.
abstract: METHODS
  Victoria, Australia.
  
  
  OBJECTIVE
  To measure the level of Mycobacterium tuberculosis transmission in Victoria.
  
  
  METHODS
  Retrospective analysis of mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR) typing profiles from all first M. tuberculosis complex (MTC) isolates obtained from patients residing in Victoria from 2003 to 2010 was performed. State TB reference laboratory records were matched with Department of Health notification records to obtain further laboratory, demographic, contact investigation, clinical and treatment data. These data were used to assign patients to one of four categories: 1) no epidemiological link, 2) possible link, 3) likely transmission event and 4) laboratory contamination.
  
  
  RESULTS
  A total of 2377 MTC isolates were genotyped using 15-locus MIRU-VNTR. Of the 2298 M. tuberculosis isolates, 1029 (44.8%) had unique genotypic profiles and were considered epidemiologically unrelated, while 1269 (55.2%) isolates shared a profile with one or more other strains, defined as a genotypic cluster. Systematic investigation of all 268 genotypic clusters, including 24-locus MIRU-VNTR on selected isolates, led to a further 862 patients being classified as unrelated, bringing the total number of patients with no epidemiological links to 1891 (82.3%). Of the remaining patients, 294 (12.8%) were classified as having possible epidemiological links, 96 (4.2%) were classified as having known epidemiological links representing likely transmission events and 17 (0.7%) as the result of laboratory cross-contamination.
  
  
  CONCLUSIONS
  There is considerable genotypic diversity among Victorian MTC isolates, and the level of transmission is low.
authors.affiliation: Mycobacterium Reference Laboratory, Victorian Infectious Diseases Reference Laboratory (VIDRL), Canberra, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Globan
authors.affiliation: Mycobacterium Reference Laboratory, Victorian Infectious Diseases Reference Laboratory (VIDRL), Canberra, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Lavender
authors.affiliation: Mycobacterium Reference Laboratory, Victorian Infectious Diseases Reference Laboratory (VIDRL), Canberra, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Leslie
authors.affiliation: Victorian Tuberculosis Program, Melbourne Health, Doherty Institute, Melbourne, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Brown
authors.affiliation: Victorian Tuberculosis Program, Melbourne Health, Doherty Institute, Melbourne, Department of Microbiology and Immunology, University of Melbourne, Parkville, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Denholm
authors.affiliation: Mycobacterium Reference Laboratory, Victorian Infectious Diseases Reference Laboratory (VIDRL), Canberra, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Raios
authors.affiliation: Mycobacterium Reference Laboratory, Victorian Infectious Diseases Reference Laboratory (VIDRL), Canberra, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Sievers
authors.affiliation: Epidemiology Unit, VIDRL, Doherty Institute, Melbourne, Victoria, National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia.
authors.forename: H
authors.initials: H
authors.lastname: Kelly
authors.affiliation: Mycobacterium Reference Laboratory, Victorian Infectious Diseases Reference Laboratory (VIDRL), Canberra, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Fyfe
mesh_terms: D001431:Bacteriological Techniques; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics* / Q000302:isolation & purification; D005838:Genotype; D006801:Humans; D018598:Minisatellite Repeats; D025202:Molecular Diagnostic Techniques; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D010802:Phylogeny; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013997:Time Factors; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology* / Q000635:transmission; D014739:Victoria / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial