The effects of HIV infection and antiretroviral therapy (ART) on the gut microbiome are poorly understood and the literature data are inconsistent. The aim of this study was to assess the alpha and beta diversity of the fecal microbiota in HIV-infected patients on successful antiretroviral therapy with regard to sexual preferences and CD4 nadir. Thirty-six HIV-infected ART-treated patients with HIV viremia below 20 copies/ml and CD4 > 500 cells/μl were divided into two subgroups based on CD4 nadir. The composition of the intestinal microbiota was assessed by 16SrRNA sequencing (MiSeq Illumina). The alpha and beta diversity were analyzed according to CD4 nadir count and sexual preference. Several alpha diversity indexes were significantly higher in the MSM group than in heterosexual patients. The alpha diversity did not differ significantly between patients with CD4 nadir > 500 cells/μl and CD4 nadir < 200 cells/μl. Beta diversity was also associated with sexual preference. A significant difference in Weighted Unifrac was observed between all MSM and all non-MSM participants (p = 0.001). The MSM group was more diverse and demonstrated greater distances in Weighted Unifrac than the non-MSM group. The relative abundance of the Prevotella enterotype was higher in the MSM than the non-MSM group. Sexual preferences demonstrated a stronger influence on alpha and beta diversity in HIV-infected patients following successful antiretroviral treatment than HIV infection itself. The observed lack of association between CD4 nadir and alpha and beta diversity may be caused by the restoration of the faecal microbiota following antiretroviral treatment.

HIV 感染和抗逆转录病毒疗法 (ART) 对肠道微生物组的影响知之甚少，文献数据也不一致。本研究的目的是评估成功抗逆转录病毒治疗的 HIV 感染患者粪便微生物群的 alpha 和 beta 多样性，包括性偏好和 CD4 最低点。将 36 名 HIV 病毒血症低于 20 拷贝/ml 且 CD4 > 500 个细胞/μl 的 HIV 感染 ART 治疗患者根据 CD4 最低点分为两个亚组。通过 16SrRNA 测序（MiSeq Illumina）评估肠道微生物群的组成。根据 CD4 最低点计数和性偏好分析 alpha 和 beta 多样性。MSM 组的几个 alpha 多样性指数显着高于异性恋患者。CD4 最低点 > 500 个细胞/μl 和 CD4 最低点 < 200 个细胞/μl 的患者之间的 alpha 多样性没有显着差异。Beta 多样性也与性偏好有关。在所有 MSM 和所有非 MSM 参与者之间观察到加权 Unifrac 的显着差异（p  = 0.001）。与非 MSM 组相比，MSM 组更加多样化，并且在加权 Unifrac 中表现出更大的距离。MSM 组中普雷沃氏菌肠型的相对丰度高于非 MSM 组。与 HIV 感染本身相比，在成功接受抗逆转录病毒治疗后，性偏好对 HIV 感染患者的 alpha 和 beta 多样性的影响更大。观察到的 CD4 最低点与 alpha 和 beta 多样性之间缺乏关联可能是由于抗逆转录病毒治疗后粪便微生物群的恢复所致。