title: Molecular epidemiology of HIV type 1 in Mexico: emergence of BG and BF intersubtype recombinants.
abstract: The molecular epidemiology of subtypes and intersubtype recombinants (IRs) of human immunodeficiency virus type 1 (HIV-1) in Mexico has not been characterized fully. Understanding its regional distribution, prevalence, adaptability, viral fitness, pathogenicity, and immunogenicity is decisive for any design of an effective HIV vaccine. The aim of this study was to describe the presence of IRs types BG and BF in a Mexican population. Protease and reverse transcriptase regions of the pol gene were sequenced using an automated sequencing system. A phylogenic tree was constructed and genetic distances were calculated using MEGA 3.1. Recombination analysis was done by bootscan using SimPlot software. Two hundred and twenty-three HIV-1-positive individuals were enrolled in the study. At baseline, the mean plasma viral load was 285,500 HIV-1 RNA copies/ml and the mean CD4 cell count was 213 cells/ml. Subtype B was found in 220 (98.6%) samples, whereas IRs were found in three patients (1.4%): two (0.9%) with BG and one (0.45%) with BF. IRs were observed in 2/124 (1.6%) samples from treated patients and in 1/99 (1.0%) from naive patients. The presence of these HIV forms at low frequency points to the need for research on the diversity, geographic distribution, and evolution of other subtypes including circulating recombinant forms and IRs to understand the molecular epidemiology and tendencies of the HIV infection in Mexico.
authors.affiliation: UMAE de Especialidades, Centro Médico Nacional de Occidente, Instituto Mexicano del Seguro Social, Colonia Independencia, Guadalajara, Jalisco, México.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Vázquez-Valls
authors.forename: Martha
authors.initials: M
authors.lastname: Escoto-Delgadillo
authors.forename: Francisco Carlos
authors.initials: FC
authors.lastname: López-Márquez
authors.forename: Marcelo
authors.initials: M
authors.lastname: Castillero-Manzano
authors.forename: Ernesto
authors.initials: E
authors.lastname: Echegaray-Guerrero
authors.forename: Oscar Kurt
authors.initials: OK
authors.lastname: Bitzer-Quintero
authors.forename: Antonio
authors.initials: A
authors.lastname: Kobayashi-Gutiérrez
authors.forename: Blanca Miriam
authors.initials: BM
authors.lastname: Torres-Mendoza
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016000:Cluster Analysis; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D017385:Sequence Homology