title: HIV-1 subtypes in Spain: a retrospective analysis from 1995 to 2003.
abstract: OBJECTIVE
  To perform a retrospective analysis of all HIV-1 non-B variants circulating in Spain from 1995 to 2003 and extend their virological characterization.
  
  
  METHODS
  Samples from a total of 396 HIV-infected subjects with epidemiological suspicion of being infected with non-B clades were analysed during the study period. Subtyping was carried out on the protease (PR), reverse transcriptase (RT) and envelope (env) genes.
  
  
  RESULTS
  PR sequences belonging to non-B subtypes were recognized in 43.2% of cases (23 A, 13C, 6D, 3F, 118 G, 3H, 4 J and 1 U). Subtype G and AG recombinants were the most frequent variants (69%), and were found most often in subjects from West and Central Africa. Up to 70% of pol (PR, RT) sequences belonging to subtype G harboured env sequences belonging to clade A (55%), B (13.8%) or K (3.4%). Nearly half were mosaic GA viruses, and a few were CRF 14 BG viruses. Up to 14 new recombinant viruses, which could not be assigned to previously described circulating recombinant forms (CRFs), were found.
  
  
  CONCLUSIONS
  There is great diversity in the HIV-1 variants and recombinant viruses circulating in Spain. Non-B sequences may be underestimated if only the env region is examined in phylogenetic analyses. Drug resistance testing provides the advantage of pol subtyping, and its additional use for this purpose should be encouraged.
authors.affiliation: Infectious Diseases Service, Hospital Carlos III, Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Lospitao
authors.forename: A
authors.initials: A
authors.lastname: Alvarez
authors.forename: V
authors.initials: V
authors.lastname: Soriano
authors.forename: A
authors.initials: A
authors.lastname: Holguín
mesh_terms: D018791:CD4 Lymphocyte Count; D030561:Databases, Nucleic Acid; D005260:Female; D005814:Genes, Viral; D015752:Genes, env; D015751:Genes, pol; D015658:HIV Infections / Q000208:ethnology / Q000276:immunology / Q000821:virology*; D016333:HIV Protease / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008297:Male; D010802:Phylogeny; D011995:Recombination, Genetic; D012189:Retrospective Studies; D013030:Spain / Q000453:epidemiology; D019562:Viral Load
chemical_list: D054303:HIV Reverse Transcriptase; D016333:HIV Protease