Virological failure and HIV-1 drug resistance mutations among naive and antiretroviral pre-treated patients entering the ESTHER program of Calmette Hospital in Cambodia

PLoS One. 2014 Aug 28;9(8):e105736. doi: 10.1371/journal.pone.0105736. eCollection 2014.


Introduction: In resource limited settings, patients entering an antiretroviral therapy (ART) program comprise ART naive and ART pre-treated patients who may show differential virological outcomes.

Methods: This retrospective study, conducted in 2010-2012 in the HIV clinic of Calmette Hospital located in Phnom Penh (Cambodia) assessed virological failure (VF) rates and patterns of drug resistance of naive and pre-treated patients. Naive and ART pre-treated patients were included when a Viral Load (VL) was performed during the first year of ART for naive subjects or at the first consultation for pre-treated individuals. Patients showing Virological failure (VF) (>1,000 copies/ml) underwent HIV DR genotyping testing. Interpretation of drug resistance mutations was done according to 2013 version 23 ANRS algorithms.

Results: On a total of 209 patients, 164 (78.4%) were naive and 45 (21.5%) were ART pre-treated. Their median initial CD4 counts were 74 cells/mm3 (IQR: 30-194) and 279 cells/mm3 (IQR: 103-455) (p<0.001), respectively. Twenty seven patients (12.9%) exhibited VF (95% CI: 8.6-18.2%), including 10 naive (10/164, 6.0%) and 17 pre-treated (17/45, 37.8%) patients (p<0.001). Among these viremic patients, twenty-two (81.4%) were sequenced in reverse transcriptase and protease coding regions. Overall, 19 (86.3%) harbored ≥1 drug resistance mutations (DRMs) whereas 3 (all belonging to pre-treated patients) harbored wild-types viruses. The most frequent DRMs were M184V (86.3%), K103N (45.5%) and thymidine analog mutations (TAMs) (40.9%). Two (13.3%) pre-treated patients harbored viruses that showed a multi-nucleos(t)ide resistance including Q151M, K65R, E33A/D, E44A/D mutations.

Conclusion: In Cambodia, VF rates were low for naive patients but the emergence of DRMs to NNRTI and 3TC occurred relatively quickly in this subgroup. In pre-treated patients, VF rates were much higher and TAMs were relatively common. HIV genotypic assays before ART initiation and for ART pre-treated patients infection should be considered as well.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-HIV Agents / therapeutic use*
  • Anti-Retroviral Agents / therapeutic use*
  • Cambodia
  • Drug Resistance, Viral / genetics*
  • Female
  • Genotype
  • HIV Infections / drug therapy*
  • HIV Infections / genetics
  • HIV-1
  • Humans
  • Male
  • Middle Aged
  • Mutation
  • Retrospective Studies
  • Treatment Failure
  • Viral Load


  • Anti-HIV Agents
  • Anti-Retroviral Agents

Grants and funding

Funds to allow the follow up of patients were granted by Esther French program. SG received a 6 months scholarship from ANRS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.