title: Identification of new, emerging HIV-1 unique recombinant forms and drug resistant viruses circulating in Cameroon.
abstract: BACKGROUND
  The HIV epidemic in Cameroon is characterized by a high degree of viral genetic diversity with circulating recombinant forms (CRFs) being predominant. The goal of our study was to determine recent trends in virus evolution and emergence of drug resistance in blood donors and HIV positive patients.
  
  
  METHODS
  Blood specimens of 73 individuals were collected from three cities and a few villages in Cameroon and viruses were isolated by co-cultivation with PBMCs. Nested PCR was performed for gag p17 (670 bp) pol (840 bp) and Env gp41 (461 bp) genes. Sequences were phylogenetically analyzed using a reference set of sequences from the Los Alamos database.
  
  
  RESULTS
  Phylogenetic analysis based on partial sequences revealed that 65% (n = 48) of strains were CRF02_AG, 4% (n = 3) subtype F2, 1% each belonged to CRF06 (n = 1), CRF11 (n = 1), subtype G (n = 1), subtype D (n = 1), CRF22_01A1 (n = 1), and 26% (n = 18) were Unique Recombinant Forms (URFs). Most URFs contained CRF02_AG in one or two HIV gene fragments analyzed. Furthermore, pol sequences of 61 viruses revealed drug resistance in 55.5% of patients on therapy and 44% of drug naïve individuals in the RT and protease regions. Overall URFs that had a primary HIV subtype designation in the pol region showed higher HIV-1 p24 levels than other recombinant forms in cell culture based replication kinetics studies.
  
  
  CONCLUSIONS
  Our results indicate that although CRF02_AG continues to be the predominant strain in Cameroon, phylogenetically the HIV epidemic is continuing to evolve as multiple recombinants of CRF02_AG and URFs were identified in the individuals studied. CRF02_AG recombinants that contained the pol region of a primary subtype showed higher replicative advantage than other variants. Identification of drug resistant strains in drug-naïve patients suggests that these viruses are being transmitted in the population studied. Our findings support the need for continued molecular surveillance in this region of West Central Africa and investigating impact of variants on diagnostics, viral load and drug resistance assays on an ongoing basis.
authors.affiliation: Lab of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
authors.forename: Viswanath
authors.initials: V
authors.lastname: Ragupathy
authors.forename: Jiangqin
authors.initials: J
authors.lastname: Zhao
authors.forename: Owen
authors.initials: O
authors.lastname: Wood
authors.forename: Shixing
authors.initials: S
authors.lastname: Tang
authors.forename: Sherwin
authors.initials: S
authors.lastname: Lee
authors.forename: Phillipe
authors.initials: P
authors.lastname: Nyambi
authors.forename: Indira
authors.initials: I
authors.lastname: Hewlett
mesh_terms: D000293:Adolescent; D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002163:Cameroon / Q000453:epidemiology; D016000:Cluster Analysis; D024882:Drug Resistance, Viral; D019143:Evolution, Molecular; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012424:Rural Population; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014505:Urban Population; D055815:Young Adult; D054299:env Gene Products, Human Immunodeficiency Virus / Q000235:genetics; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000235:genetics; D054302:pol Gene Products, Human Immunodeficiency Virus / Q000235:genetics
chemical_list: D019380:Anti-HIV Agents; D054299:env Gene Products, Human Immunodeficiency Virus; D054301:gag Gene Products, Human Immunodeficiency Virus; D054302:pol Gene Products, Human Immunodeficiency Virus