CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

Principal component analysis of the gut microbiome of patient samples obtained at each timepoint. Each dot, labeled with a letter followed by a number, corresponds to a single sample in which each letter (A through M) corresponds to a patient and the number (0 through 48) identifies at which week the sample was taken. Red points belong to the MVC- group and blue points belong to the MVC+ group. There is no evidence of clusting by MVC group. Conclusions: In early HIV infection, CCR5 blockade with MVC may be a potent antiviral strategy for reducing the depletion of CD4 lymphocytes in the gut but, it does not significantly alter the gut microbiome. As such, Maraviroc may be a beneficial addition to treatment strategies involving reshaping the gut microbiome.

264 Fecal Microbiota of HIV Controllers Is Similar to That of Non – HIV-Infected Individuals Selma N. Alva Hernández ; Sandra M. Pinto Cardoso; NormaTéllez; Akio Murakami-Ogasawara; Gustavo Reyes-Terán National Institute of Respiratory Diseases, Research Center in Infectious Diseases, Mexico City, Mexico

Background: Less than 5% of the HIV-infected population is able to control HIV infection in the absence of antiretroviral therapy (ART). This population is commonly defined as HIV controllers (HIC). Studying this population represents a unique opportunity to understand the mechanisms responsible for HIV control. The aim of this study was to address whether HIC have the same alterations in the composition of their gut microbiota as described in chronic HIV infected individuals naïve to ART (CI). Methods: All participants gave written informed consent. DNA was extracted from stool samples collected from 20 CI, 6 HIC (as defined by viral loads below of 2,000 copies of RNA/mL) and 9 non-HIV-infected individuals (NI). The V3 region of the 16S rRNA gene was PCR amplified and sequenced using a semiconductor sequencer. After quality filtering, taxonomic assignment and alpha diversity (rarefied at 49,208 sequences/sample) were computed using QIIME 1.8.0. Comparisons between groups were performed using Mann- Whitney U-test and Kruskal-Wallis test (GraphPad Prism 5). Results: Median CD4 counts were 436 cells/mm 3 (237-821) and 947 cells/mm 3 (482-1,160) for CI and HIC respectively; p=0.002. Median plasma viral loads were 74,408 copies of RNA/mL (3,462-2,030,199) and 62 copies of RNA/mL (<40-447) for CI and HIC respectively; p=0.0003. As previously reported, we found lower microbiota diversity in CI than in NI (1,195 ± SD 487 vs 1,652 ± 296, p=0.040). Interestingly, no differences in microbiota diversity were observed between HIC and NI (1,472 ± 655 vs 1,652 ± 296, p=0.689). We found three predominant phyla: Bacteroidetes, Firmicutes and Proteobacteria with an overall median relative abundance of 83.9% ± 17.7%, 11.9 ± 11.6% and 2.0% ± 11.0%, respectively. No significant overall differences were observed at phylum level (p=0.442, 0.479 and 0.555, respectively). However, at family level, we found a significantly lower abundance of both Ruminococcaceae and Lachnospiraceae in CI when compared to NI (p=0.028 and 0.008, respectively). At genus level, no significant differences were found between Prevotella and Bacteroides , the two most abundant genera belonging to the phylum Bacteroidetes , and reported altered in CI (p=0.335 and 0.536, respectively). Conclusions: HIV controllers do not have significant alterations in gut microbiota composition, previously reported in chronic HIV infected individuals naïve to ART. The fecal microbiota of HIV controllers resembles that of non-HIV-infected individuals. 265 Impact of 2 Antiretroviral Regimens on Fecal Microbial Diversity and Composition Sandra M. Pinto Cardoso ; Selma N. Alva Hernández; NormaTéllez; Akio Murakami-Ogasawara; Gustavo Reyes-Terán National Institute of Respiratory Diseases, Mexico City, Mexico Background: Reports have shown that microbial composition of individuals on antiretroviral therapy (ART) is different from that of non-HIV-infected individuals. However, the degree to which ART restores the microbial composition remains unclear. The aim of this study was to determine the effect of two types of ART regimens: Efavirenz-based regimen (EFV) and protease inhibitor-based regimen (PI) boosted with either Lopinavir (LPV/r) or Atazanavir (ATV/r) on fecal microbial diversity and composition. Methods: All individuals gave informed consent. Fecal samples were obtained from 37 HIV-infected individuals: 20 on EFV-based regimen and 17 on a PI-based regimen and 9 non-HIV-infected individuals. The V3 region of the 16S rRNA gene was PCR amplified and sequenced on a semiconductor sequencer. Alpha diversity computation (observed species rarified at 49,208 sequences/sample), operational taxonomic unit (OTU) picking at 97% ID and taxonomy assignment was performed using QIIME 1.8.0. Statistical analysis was performed using two-tailed Mann-Whitney U-test (GraphPad Prism 6). Results: Median CD4 counts were 457 cells/mm3 (235-1247) and 559 cells/mm3 (240-1177) for individuals on EFV- and PI-based regimen respectively (p=0.174). All individuals on ART had undetectable viral loads. Median duration of ART was 70 months ± SD 33.36. Individuals under EFV- had significantly lower diversity compared to those on PI-based regimen (p=0.0304) and to non-HIV-infected controls (p=0.0030). Microbial communities were profiled and four predominant phyla were found: Bacteroidetes, Firmicutes, Proteobacteria and Fusobacteria. The phylum Fusobacteria was only observed in individuals under EFV-based regimen (overall RA= 3.591% ± SD 9.05%). The relative abundance

Poster Abstracts

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CROI 2015