title: Low HIV-1 transmitted drug resistance in Bulgaria against a background of high clade diversity.
abstract: OBJECTIVE
  To determine transmitted drug resistance (TDR) and HIV-1 genetic diversity in Bulgaria.
  
  
  METHODS
  The prevalence of TDR and HIV-1 subtypes was determined in 305/1446 (21.1%) persons newly diagnosed with HIV/AIDS from 1988 to 2011. TDR mutations (TDRMs) in protease and reverse transcriptase were defined using the WHO HIV drug mutation list. Phylogenetic analysis was used to infer polymerase (pol) genotype.
  
  
  RESULTS
  TDRMs were found in 16/305 (5.2%) persons, 11 (3.6%) with resistance to NRTIs, 5 (1.6%) with resistance to NNRTIs and 3 (0.9%) with resistance to PIs. Dual-class TDRMs were found in three (1.0%) patients and one statistically supported cluster of TDRMs comprising two individuals with subtype B infection. TDRMs were found in 10 heterosexuals, 4 MSM and two intravenous drug users. Phylogenetic analyses identified high HIV-1 diversity consisting of mostly subtype B (44.6%), subtype C (3.3%), sub-subtype A1 (2.6%), sub-subtype F1 (2.3%), sub-subtype A-like (3.6%), subtype G (0.3%), CRF14_BG (1.6%), CRF05_DF (1.3%), CRF03_AB (0.3%) and unique recombinant forms (1.3%).
  
  
  CONCLUSIONS
  We found a low prevalence of TDR against a background of high HIV-1 genetic diversity among antiretroviral-naive patients in Bulgaria. Our results provide baseline data on TDR and support continued surveillance of high-risk populations in Bulgaria to better target treatment and prevention efforts.
authors: National Reference Laboratory of HIV, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria ivoalexiev@yahoo.com.
authors: Ivailo
authors: I
authors: Alexiev
authors: Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors: Anupama
authors: A
authors: Shankar
authors: University Medical Center Utrecht, Virology, Utrecht, The Netherlands.
authors: A M J
authors: AM
authors: Wensing
authors: National Reference Laboratory of HIV, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria.
authors: Danail
authors: D
authors: Beshkov
authors: Hospital for Infectious and Parasitic Diseases, Sofia, Bulgaria.
authors: Ivaylo
authors: I
authors: Elenkov
authors: Department of Infectious Diseases, Medical University, Plovdiv, Bulgaria.
authors: Mariyana
authors: M
authors: Stoycheva
authors: Clinic of Infectious Diseases, Medical University, Varna, Bulgaria.
authors: Daniela
authors: D
authors: Nikolova
authors: National Reference Laboratory of Immunology, National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria.
authors: Maria
authors: M
authors: Nikolova
authors: Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors: William M
authors: WM
authors: Switzer
mesh_terms: D002031:Bulgaria / Q000453:epidemiology; D018562:Disease Transmission, Infectious; D024882:Drug Resistance, Viral; D005260:Female; D014644:Genetic Variation; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission* / Q000821:virology*; D016333:HIV Protease / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D015995:Prevalence; D017422:Sequence Analysis, DNA
chemical_list: C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase; D016333:HIV Protease; C514803:p16 protease, Human immunodeficiency virus 1
keywords: antiretroviral mutations; eastern Europe; surveillance; viral heterogeneity
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