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Studies on the human virome based on the application of metagenomic approaches involve overcoming a series of challenges and limitations inherent not only to the biological features of viruses, but also to methodological pitfalls which different approaches have tried to minimize. These approaches fall into two main categories: bulk-metagenomes and virus-like particle (VLP) enrichment. In order to address issues associated with commonly used experimental procedures to assess the degree of reliability, representativeness, and reproducibility, we designed a comparative analysis applied to three experimental protocols, one based on bulk-metagenomes and two based on VLP enrichment. These protocols were applied to stool samples from 10 adult participants, including two replicas per protocol and subject. We evaluated the performances of the three methods, not only through the analysis of the resulting composition, abundance, and diversity of the virome via taxonomical classification and type of molecule (DNA versus RNA, single stranded vs. double stranded), but also according to how the a priori identical replicas differed from each other according to the extraction methods used. Our results highlight the strengths and weaknesses of each approach, offering valuable insights and tailored recommendations for drawing reliable conclusions based on specific research goals.

While the intestinal microbiome seems a major driver of persistent immune defects in people with HIV (PWH), little is known about its fungal component, the mycobiome. We assessed the inter-kingdom mycobiome–bacteriome interactions, the impact of diet, and the association with the innate and adaptive immunity in PWH on antiretroviral therapy. We included 24 PWH individuals and 12 healthy controls. We sequenced the Internal Transcribed Spacer 2 amplicons, determined amplicon sequence variants, measured biomarkers of the innate and adaptive immunity in blood and relations with diet. Compared to healthy controls, PWH subjects exhibited a distinct and richer mycobiome and an enrichment for Debaryomyces hansenii, Candida albicans, and Candida parapsilosis. In PWH, Candida and Pichia species were strongly correlated with several bacterial genera, including Faecalibacterium genus. Regarding the links between the mycobiome and systemic immunology, we found a positive correlation between Candida species and the levels of proinflammatory cytokines (sTNF-R2 and IL-17), interleukin 22 (a cytokine implicated in the regulation of mucosal immunity), and CD8+ T cell counts. This suggests an important role of the yeasts in systemic innate and adaptive immune responses. Finally, we identified inter-kingdom interactions implicated in fiber degradation, short-chain fatty acid production, and lipid metabolism, and an effect of vegetable and fiber intake on the mycobiome. Therefore, despite the great differences in abundance and diversity between the bacterial and fungal communities of the gut, we defined the changes associated with HIV, determined several different inter-kingdom associations, and found links between the mycobiome, nutrient metabolism, and systemic immunity, European Development Regional Found "A way to achieve Europe" (ERDF), Instituto de Salud Carlos III, Depto. de Nutrición y Ciencia de los Alimentos, Fac. de Farmacia, TRUE, pub

Aims: Children with HIV exhibit chronic inflammation and immune dysfunction despite antiretroviral therapy (ART). Strategies targeting persistent inflammation are needed to improve health in people living with HIV. The gut microbiota likely interacts with the immune system, but the clinical implications of modulating the dysbiosis by nutritional supplementation are unclear. Methods: Pilot, double-blind, randomized placebo-controlled trial in which 24 HIV-infected on ART were randomized to supplementation with a daily mixture of symbiotics, omega-3/6 fatty acids and amino acids, or placebo four weeks, in combination with ART. We analyzed inflammatory markers and T-cell activation changes and their correlations with shifts in fecal microbiota. Results: Twenty-four HIV-infected children were recruited and randomized to receive a symbiotic nutritional supplement or placebo. Mean age was 12 ± 3.9 years, 62.5% were female. All were on ART and had HIV RNA < 50/mL. We did not detect changes in inflammatory (IL-6, IL-7, IP-10), microbial translocation (sCD14), mucosal integrity markers (IFABP, zonulin) or the kynurenine to tryptophan ratio, or changes in markers of the adaptive immune response in relation to the intervention. However, we found correlations between several key bacteria and the assessed inflammatory and immunological parameters, supporting a role of the microbiota in immune modulation in children with HIV. Conclusions: In this exploratory study, a four-week nutritional supplementation had no significant effects in terms of decreasing inflammation, microbial translocation, or T-cell activation in HIV-infected children. However, the correlations found support the interaction between gut microbiota and the immune system., Instituto de Salud Carlos III (ISCIII)/ FEDER, Instituto de Salud Carlos III, Spanish Society of Microbiology and Infectious Diseases (SEIMC)/Spanish Ministry of Science and Innovation/Instituto de Salud Carlos III/FEDER, Depto. de Medicina, Depto. de Salud Pública y Materno - Infantil, Fac. de Medicina, TRUE, pub

This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Journal of Agricultural and Food Chemistry, copyright © American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/acs.jafc.0c02088, [EN] Globalization of fruit and vegetable markets generates overproduction, surpluses, and potentially valuable residues. The valorization of these byproducts constitutes a challenge, to ensure sustainability and reintroduce them into the food chain. This work focuses on blueberry and persimmon residues, rich in polyphenols and carotenoids, to obtain powders with high added value to be used as ingredients in food formulation. These powders have been characterized, and the changes in the bioactive compounds in in vitro gastrointestinal digestion have been evaluated. The results indicated that the type of residue, the drying process, as well as the content and type of fiber determine the release of antioxidants during digestion. In vitro colonic fermentations were also performed, and it was observed that the characteristics of digested powders had an effect on the composition of the growing microbial community. Thus, carotenoids and anthocyanins maintain an interplay with microbiota that could be beneficial for human health.

[Aims]: The gut microbiota exerts a critical influence in the immune system. The gut microbiota of human virus immunodeficiency (HIV)-infected children remains barely explored. We aimed to characterize the fecal microbiota in vertically HIV-infected children and to explore the effects of its modulation with a symbiotic nutritional intervention., [Methods]: A pilot, double blind, randomized placebo-controlled study including HIV-infected children who were randomized to receive a nutritional supplementation including prebiotics and probiotics or placebo for four weeks. HIV-uninfected siblings were recruited as controls. The V3–V4 region of the 16S rRNA gene was sequenced in fecal samples., [Results]: 22 HIV-infected children on antiretroviral therapy (ART) and with viral load (VL) <50/mL completed the follow-up period. Mean age was 11.4 ± 3.4 years, eight (32%) were male. Their microbiota showed reduced alpha diversity compared to controls and distinct beta diversity at the genus level (Adonis p = 0.042). Patients showed decreased abundance of commensals Faecalibacterium and an increase in Prevotella, Akkermansia and Escherichia. The nutritional intervention shaped the microbiota towards the control group, without a clear directionality., [Conclusions]: Vertical HIV infection is characterized by changes in gut microbiota structure, distinct at the compositional level from the findings reported in adults. A short nutritional intervention attenuated bacterial dysbiosis, without clear changes at the community level., [Summary]: In a group of 24 vertically HIV-infected children, in comparison to 11 uninfected controls, intestinal dysbiosis was observed despite effective ART. Although not fully effective to restore the microbiota, a short intervention with pre/probiotics attenuated bacterial dysbiosis.

Human immunodeficiency virus (HIV) infection is characterized by an early depletion of the mucosal associated T helper (CD4+) cells that impair the host immunity and impact the oral and gut microbiomes. Although, the HIV-associated gut microbiota was studied in depth, few works addressed the dysbiosis of oral microbiota in HIV infection and, to our knowledge, no studies on intervention with prebiotics were performed. We studied the effect of a six-week-long prebiotic administration on the salivary microbiota in HIV patients and healthy subjects. Also, the co-occurrence of saliva microorganisms in the fecal bacteria community was explored. We assessed salivary and feces microbiota composition using deep 16S ribosomal RNA (rRNA) gene sequencing with Illumina methodology. At baseline, the different groups shared the same most abundant genera, but the HIV status had an impact on the saliva microbiota composition and diversity parameters. After the intervention with prebiotics, we found a drastic decrease in alpha diversity parameters, as well as a change of beta diversity, without a clear directionality toward a healthy microbiota. Interestingly, we found a differential response to the prebiotics, depending on the initial microbiota. On the basis of 100% identity clustering, we detected saliva sequences in the feces datasets, suggesting a drag of microorganisms from the upper to the lower gastrointestinal tract.

The term “bacterial dysbiosis” is being used quite extensively in metagenomic studies, however, the identification of harmful bacteria often fails due to large overlap between the bacterial species found in healthy volunteers and patients. We hypothesized that the pathogenic oral bacteria are individual-specific and they correlate with oxidative stress markers in saliva which reflect the inflammatory processes in the oral cavity. Temporally direct and lagged correlations between the markers and bacterial taxa were computed individually for 26 volunteers who provided saliva samples during one month (21.2 ± 2.7 samples/volunteer, 551 samples in total). The volunteers’ microbiomes differed significantly by their composition and also by their degree of microbiome temporal variability and oxidative stress markers fluctuation. The results showed that each of the marker-taxa pairs can have negative correlations in some volunteers while positive in others. Streptococcus mutans, which used to be associated with caries before the metagenomics era, had the most prominent correlations with the oxidative stress markers, however, these correlations were not confirmed in all volunteers. The importance of longitudinal samples collections in correlation studies was underlined by simulation of single sample collections in 1000 different combinations which produced contradictory results. In conclusion, the distinct intra-individual correlation patterns suggest that different bacterial consortia might be involved in the oxidative stress induction in each human subject. In the future, decreasing cost of DNA sequencing will allow to analyze multiple samples from each patient, which might help to explore potential diagnostic applications and understand pathogenesis of microbiome-associated oral diseases.

HIV infection causes a disruption of gut-associated lymphoid tissue, driving a shift in the composition of gut microbiota. A deeper understanding of the metabolic changes and how they affect the interplay with the host is needed. Here, we assessed functional modifications of HIV-associated microbiota by combining metagenomic and metatranscriptomic analyses. The transcriptionally active microbiota was well-adapted to the inflamed environment, overexpressing pathways related to resistance to oxidative stress. Furthermore, gut inflammation was maintained by the Gram-negative nature of the HIV-associated microbiota and underexpression of anti-inflammatory processes, such as short chain fatty acid biosynthesis or indole production. We performed co-occurrence and metabolic network analyses that showed relevance in the microbiota structure of both taxonomic and metabolic HIV-associated biomarkers. The Bayesian network revealed the most determinant pathways for maintaining the structure stability of the bacterial community. In addition, we identified the taxa's contribution to metabolic activities and their interactions with host health.