title: Low prevalence of transmitted drug resistance in patients newly diagnosed with HIV-1 infection in Sweden 2003-2010.
abstract: Transmitted drug resistance (TDR) is a clinical and epidemiological problem because it may contribute to failure of antiretroviral treatment. The prevalence of TDR varies geographically, and its prevalence in Sweden during the last decade has not been reported. Plasma samples from 1,463 patients newly diagnosed with HIV-1 infection between 2003 and 2010, representing 44% of all patients diagnosed in Sweden during this period, were analyzed using the WHO 2009 list of mutations for surveillance of TDR. Maximum likelihood phylogenetic analyses were used to determine genetic subtype and to investigate the relatedness of the sequences. Eighty-two patients showed evidence of TDR, representing a prevalence of 5.6% (95% CI: 4.5%-6.9%) without any significant time trends or differences between patients infected in Sweden or abroad. Multivariable logistic regression showed that TDR was positively associated with men who have sex with men (MSM) and subtype B infection and negatively associated with CD4 cell counts. Among patients with TDR, 54 (68%) had single resistance mutations, whereas five patients had multi-drug resistant HIV-1. Phylogenetic analyses identified nine significantly supported clusters involving 29 of the patients with TDR, including 23 of 42 (55%) of the patients with TDR acquired in Sweden. One cluster contained 18 viruses with a M41L resistance mutation, which had spread among MSM in Stockholm over a period of at least 16 years (1994-2010). Another cluster, which contained the five multidrug resistant viruses, also involved MSM from Stockholm. The prevalence of TDR in Sweden 2003-2010 was lower than in many other European countries. TDR was concentrated among MSM, where clustering of TDR strains was observed, which highlights the need for continued and improved measures for targeted interventions.
authors.affiliation: Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden.
authors.forename: Annika
authors.initials: A
authors.lastname: Karlsson
authors.forename: Per
authors.initials: P
authors.lastname: Björkman
authors.forename: Göran
authors.initials: G
authors.lastname: Bratt
authors.forename: Håkan
authors.initials: H
authors.lastname: Ekvall
authors.forename: Magnus
authors.initials: M
authors.lastname: Gisslén
authors.forename: Anders
authors.initials: A
authors.lastname: Sönnerborg
authors.forename: Mattias
authors.initials: M
authors.lastname: Mild
authors.forename: Jan
authors.initials: J
authors.lastname: Albert
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000494:pharmacology / Q000627:therapeutic use; D018791:CD4 Lymphocyte Count; D002648:Child; D002675:Child, Preschool; D024882:Drug Resistance, Viral; D005260:Female; D015658:HIV Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D015497:HIV-1 / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D018451:Homosexuality, Male; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012367:RNA, Viral / Q000235:genetics; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral