title: Multidrug-resistant tuberculosis in Norway: a nationwide study, 1995-2014.
abstract: The management of multidrug-resistant tuberculosis (MDR-TB) is strictly regulated in Norway. However, nationwide studies of the epidemic are lacking.
  
  
  
  To describe the MDR-TB epidemic in Norway over two decades.
  
  
  
  Retrospective analysis of data on MDR-TB cases in Norway, 1995-2014, obtained from the national registry, patient records and the reference laboratory, with genotyping and cluster analysis data. Data for non-MDR-TB cases were collected from the national registry.
  
  
  
  Of 4427 TB cases, 89 (2.0%) had MDR-TB, 7% of whom had extensively drug-resistant TB (XDR-TB) and 24% pre-XDR-TB. Of the 89 MDR-TB cases, 96% were immigrants, mainly from the Horn of Africa or the former Soviet Union (FSU); 37% had smear-positive TB; and 4% were human immunodeficiency virus co-infected. Of the 19% infected in Norway, the majority belonged to a Delhi/Central Asian lineage cluster in a local Somali community. Among the MDR-TB cases, smear-positive TB and FSU origin were independent risk factors for XDR/pre-XDR-TB. Treatment was successful in 66%; 17% were lost to follow-up, with illicit drug use and adolescence being independent risk factors. Forty-four per cent of patients treated with linezolid discontinued treatment due to adverse effects.
  
  
  
  MDR-TB is rare in Norway and is predominantly seen in immigrants from the Horn of Africa and FSU. Domestic transmission outside immigrant populations is minimal.
authors.affiliation: Department of Infectious Diseases, Oslo University Hospital, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Jensenius
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: B A
authors.initials: BA
authors.lastname: Winje
authors.affiliation: Department of Medicine, Haukeland University Hospital, Bergen, Norway; Department of Clinical Science, University of Bergen, Bergen, Norway.
authors.forename: B
authors.initials: B
authors.lastname: Blomberg
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: A T
authors.initials: AT
authors.lastname: Mengshoel
authors.affiliation: Department of Infectious Diseases, Oslo University Hospital, Oslo, Norway.
authors.forename: B von der
authors.initials: Bv
authors.lastname: Lippe
authors.affiliation: Department of Infectious Diseases, Trondheim University Hospital, Trondheim, Norway.
authors.forename: R
authors.initials: R
authors.lastname: Hannula
authors.affiliation: Department of Infectious Diseases, Tromsø University Hospital, Tromsø, Norway; Department of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway; Institute of Clinical Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: J N
authors.initials: JN
authors.lastname: Bruun
authors.affiliation: Department of Paediatrics, Oslo University Hospital, Oslo, Norway.
authors.forename: P K
authors.initials: PK
authors.lastname: Knudsen
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: J O
authors.initials: JO
authors.lastname: Rønning
authors.affiliation: Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Heldal
authors.affiliation: Department of Infectious Diseases, Oslo University Hospital, Oslo, Norway; Department of Clinical Science, University of Bergen, Bergen, Norway; Institute of Clinical Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: A M
authors.initials: AM
authors.lastname: Dyrhol-Riise
mesh_terms: D000293:Adolescent; D000328:Adult; D000349:Africa / Q000208:ethnology; D000995:Antitubercular Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D054242:Emigrants and Immigrants; D058872:Epidemics; D054908:Extensively Drug-Resistant Tuberculosis / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D060005:Genotyping Techniques; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology*; D006801:Humans; D000069349:Linezolid / Q000627:therapeutic use; D059012:Lost to Follow-Up; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy / Q000453:epidemiology*; D014586:USSR / Q000208:ethnology; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents; D000069349:Linezolid