title: Detection of the protease codon 35 amino acid insertion in sequences from treatment-naïve HIV-1 subtype C infected individuals in the Central Region of Portugal.
abstract: BACKGROUND
  Amino acids insertions in the protease (PR) coding region have been reported in protease inhibitors (PIs) treatment-naïve and experienced HIV-1 infected individuals ranging from 0.1% to 4.55% and have been rarely found in non-B HIV-1 subtype strains.
  
  
  OBJECTIVE
  To investigate the presence of amino acid insertions in the PR coding region in sequences from treatment-naïve HIV-1 infected individuals in the Central Region of Portugal.
  
  
  METHODS
  Sequences of the pol gene from 260 treatment-naïve HIV-1 infected individuals between 2000 and 2008 were analyzed and phylogenetic analysis was performed.
  
  
  RESULTS
  A threonine insertion (E35E_T) was detected in 2.69% (n=7) of the sequences analyzed and all the sequences that possessed this insertion were identified as subtype C. All the seven inserted sequences clustered in the same lineage of the phylogenetic tree. Heterosexual and intravenous drug use were found to be the routes of infection. No major mutations in the PR coding region associated with resistance to PIs were detected.
  
  
  CONCLUSIONS
  It was found the highest prevalence of PR codon 35 insertion among treatment-naïve HIV-1 infected individuals ever reported in the western countries. Epidemiological data and Phylogenetic analysis indicated the possibility of transmission of this insertion. The results suggested that these inserted strains have normal susceptibility to PIs containing regimens. This study demonstrated the spreading epidemic of PR codon 35 inserted strains from subtype C in the Central Region of Portugal, during the past eight years.
authors.affiliation: Laboratório de Virologia do Departamento de Doenças Infecciosas, Hospitais da Universidade de Coimbra, Coimbra, Portugal. joaovaz@huc.min-saude.pt
authors.forename: João
authors.initials: J
authors.lastname: Pereira-Vaz
authors.forename: Vitor
authors.initials: V
authors.lastname: Duque
authors.forename: Luís
authors.initials: L
authors.lastname: Trindade
authors.forename: José
authors.initials: J
authors.lastname: Saraiva-da-Cunha
authors.forename: António
authors.initials: A
authors.lastname: Meliço-Silvestre
mesh_terms: D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000821:virology*; D016333:HIV Protease / Q000235:genetics*; D015497:HIV-1 / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D008297:Male; D016254:Mutagenesis, Insertional / Q000235:genetics*; D010802:Phylogeny; D011174:Portugal / Q000453:epidemiology
chemical_list: D016333:HIV Protease