Traditionally, the gut microbiome has been recognized as a pivotal modulator of host health and immune responses. HIV infection, characterized by immunodeficiency and chronic inflammation, has been known to perturb gut microbiota composition and function. However, previous investigations were limited by geographic homogeneity and inconsistencies in antiretroviral treatment regimens, leading to ambiguous conclusions about the microbiome changes attributable to HIV versus therapy effects. By expanding the scope to include cohorts from sub-Saharan Africa and North America, the present study offers a comprehensive panorama of microbiome alterations linked to HIV, antiretroviral drugs, and their intersection influenced by environmental and population-specific factors.

One of the major findings is that taxonomic modifications in the gut microbiota induced by HIV infection are largely site-specific. Diversity metrics and bacterial taxa shifts differed substantially between Ugandan and Botswanan cohorts compared to the USA cohort, signifying that geography and local ecology substantially mold microbial responses to HIV. This geographic variance in bacterial community structure likely reflects differences in diet, lifestyle, and baseline microbiota composition that converge with the impact of immunodeficiency, resulting in distinct microbial ecosystems. Such results emphasize the necessity of incorporating diverse populations when evaluating microbiome changes in disease contexts, rather than generalizing findings from single-region studies.

Despite marked regional differences in bacterial species composition, alterations in microbial functional pathways were found to be remarkably consistent across the three examined cohorts. Functional metagenomic analyses revealed convergent perturbations in metabolic processes including amino acid metabolism, lipid biosynthesis, and redox balance, which intensified in individuals exhibiting acquired immunodeficiency syndrome (AIDS). This suggests that although the identity of the microbial players varies geographically, the biochemical repercussions of HIV-induced dysbiosis share commonalities, potentially contributing to systemic inflammation and immune dysfunction observed in HIV progression.

A striking aspect revealed relates to how antiretroviral therapy (ART), cornerstone in HIV management, imprints on the gut microbiome in a geography-dependent manner. The study highlights that the commonly used non-nucleoside reverse transcriptase inhibitor (NNRTI), efavirenz, produced divergent microbial effects in the African cohorts compared to the USA cohort. In Uganda and Botswana, efavirenz administration correlated with depletion of Prevotella species—commensal bacteria often implicated in mucosal immune modulation—and disruption of bacterial interspecies metabolic networks. Conversely, such changes were less pronounced or absent in the USA cohort, once again underscoring the modulating influence of environmental and host factors beyond HIV viral status or ART receipt alone.

The depletion of Prevotella prompted deeper mechanistic investigations given its links to health outcomes. Computational modeling and in vitro experiments illuminated a novel hypothesis wherein efavirenz cross-inhibits prokaryotic reverse transcriptases involved in bacterial antiphage defense mechanisms. These reverse transcriptases are integral to bacterial adaptive immunity against bacteriophages, and their inhibition could impair microbial survival and community balance. This unexpected off-target effect of efavirenz provides a molecular foothold explaining Prevotella reduction and poses critical questions about how ART-associated microbial perturbations might exacerbate immune activation and comorbidities such as atherosclerosis, which were observed concomitantly in the African cohorts.

Chronic systemic inflammation in people living with HIV is a key driver of non-AIDS-defining illnesses, including cardiovascular diseases. By linking efavirenz-associated Prevotella depletion to heightened inflammation and atherosclerosis markers, this study intricately connects ART-induced gut microbiome changes to downstream clinical sequelae. Such findings underscore the imperative to consider microbiome consequences in ART selection, particularly in resource-limited settings where certain regimens prevail. Tailoring therapy with microbiome preservation in mind could mitigate long-term adverse events and improve quality of life for millions.

Furthermore, this research exemplifies the complexity of host-microbiome-therapy interactions. It challenges the simplistic notion of ART effects as universally beneficial or solely focused on viral suppression, illuminating a layered landscape where treatment exerts distinct biological forces on commensal ecosystems conditioned by geography and host background. This multidimensionality advocates for precision medicine approaches that integrate microbiome profiling and geographic context into clinical decision-making.

The comprehensive metagenomic approach adopted here enabled dissection of taxonomic shifts alongside functional gene repertoires, painting a holistic picture of microbiome dynamics rather than one limited to microbial census. This is critical because functional redundancy among microbial taxa often conceals deeper ecosystem impacts; hence, identifying convergent pathway disruptions amidst taxonomic heterogeneity is particularly insightful. The study also reveals opportunities for therapeutic innovation targeting modifiable microbial pathways or mitigating ART off-target effects.

Looking ahead, these findings open several promising avenues for research and application. Longitudinal studies could elucidate causal relationships between therapy-induced microbiome changes and clinical outcomes over time. Additionally, development of adjunctive microbiome-modulating interventions, such as prebiotics or targeted bacteriophage therapies, might optimize HIV care. Moreover, integrating microbiome assessments into global HIV treatment programs could harmonize infection control with microbiome stewardship, enhancing holistic patient health.

This work also exemplifies the power of international collaborative research, integrating cohorts from diverse continents to uncover universal and local microbial effects of HIV and its treatment. Such model studies are essential to bridge global health disparities and tailor medical interventions that respect biological and cultural heterogeneity. Ultimately, acknowledging and interrogating the interface of infectious disease, microbiome ecology, geography, and pharmacology offers transformative potential for advancing personalized and global health.

In summary, this landmark study decisively broadens our understanding of how HIV and antiretroviral therapy reshape the gut microbiome across populations with distinct environmental and genetic backgrounds. It challenges prior assumptions by revealing geography-specific taxonomic modifications but functional commonalities, as well as identifying deleterious microbiome effects linked to a widely used ART agent. These insights not only deepen our mechanistic grasp of microbial-host-virus-drug interplay but also herald a new frontier wherein microbiome-informed, geography-tailored HIV treatment strategies could significantly attenuate complications and elevate patient outcomes worldwide. The implications for clinical practice and public health policy are profound and serve as a clarion call for integrating microbiome science into the future of HIV medicine.

Subject of Research:
Human immunodeficiency virus (HIV) infection and the impact of antiretroviral therapies on gut microbiome composition and function across geographically diverse populations.

Article Title:
Human immunodeficiency virus and antiretroviral therapies exert distinct influences across diverse gut microbiomes.

Article References:
Jabbar, K.S., Priya, S., Xu, J. et al. Human immunodeficiency virus and antiretroviral therapies exert distinct influences across diverse gut microbiomes. Nat Microbiol (2025). https://doi.org/10.1038/s41564-025-02157-7

Image Credits:
AI Generated

DOI:
https://doi.org/10.1038/s41564-025-02157-7

Keywords:
HIV, gut microbiome, antiretroviral therapy, efavirenz, Prevotella, metabolic pathways, systemic inflammation, atherosclerosis, reverse transcriptase inhibition, geography, microbiome function, acquired immunodeficiency syndrome

The study meticulously followed a cohort of women living with HIV, characterizing temporal changes in both the bacteriome—the community of bacteria—and the virome—the population of viruses—in the cervicovaginal environment. By employing advanced sequencing technologies combined with longitudinal sampling, the researchers dissected how these microbial communities evolve in response to antiretroviral therapy and other biological factors. The delicate equilibrium between the bacteriome and virome emerged as a pivotal determinant in whether HIV shedding into the genital tract occurs discordantly, potentially influencing transmission dynamics.

Previous investigations have focused predominantly on the bacterial component of the cervicovaginal microbiota, often linking specific bacterial profiles, such as those dominated by Lactobacillus species, to protective effects in HIV infection. However, this study ventures further by integrating the virome into the analysis, revealing that viral populations—both endogenous and exogenous—coexist and interact with bacterial communities, shaping the local microenvironment profoundly. The virome’s modulation appears not only linked to immune status but is also associated with discordant viral shedding, a phenomenon wherein detectable genital HIV RNA does not mirror systemic viral loads.

Longitudinal data demonstrated significant shifts in both bacteriome and virome compositions over the course of ART. Women with longer ART durations exhibited distinct microbial landscape profiles compared to those newly initiated or off treatment. These alterations included changes in bacterial taxa abundances and viral diversity indices, suggesting therapy’s indirect but influential role in remodeling the cervicovaginal ecosystem. Such remodeling could affect mucosal immunity, barrier functions, and susceptibility to co-infections, implicating these microbial communities as critical players in disease progression and contagion potential.

A particularly striking observation centered on the discordant shedding of HIV RNA within the genital tract. Some women, despite successful systemic viral suppression via ART, displayed intermittent or persistent genital HIV shedding. The study correlated these episodes with specific bacteriome and virome signatures, diverging substantially from profiles in women without such shedding. These findings underscore that systemic viral control does not uniformly equate to suppression at mucosal sites and that microbial community dynamics contribute to localized shedding, influencing onward HIV transmission risks.

Mechanistic insights from the study suggest that certain bacterial communities may foster an environment conducive to viral replication or persistence, whereas others may enhance antiviral defense mechanisms. For instance, depletion or imbalance of Lactobacillus species was associated with increased viral shedding, whereas dominance of other anaerobic bacteria correlated with inflammatory states that could compromise mucosal barriers. Concurrently, shifts in the virome, including changes in bacteriophages and eukaryotic viruses, might modulate bacterial populations or directly impact host immune responses, creating a multifaceted network of interactions.

This research also challenges the conventional dogma that views the virome primarily as a passive entity within mucosal sites. Instead, the virome emerges as an active architect of the microbial niche, influencing bacterial community structure and, by extension, host-pathogen interactions. The implications extend beyond HIV to other sexually transmitted infections and reproductive health, suggesting that a comprehensive understanding of mucosal ecosystems must encompass both bacterial and viral constituents.

From a clinical perspective, these findings pave the way for novel diagnostic and therapeutic strategies. Monitoring cervicovaginal bacteriome and virome profiles could serve as biomarkers to identify women at higher risk of genital HIV shedding despite systemic viral suppression. Additionally, microbiome-targeted interventions, such as probiotics or antivirals modulating viral communities, may complement ART to achieve more complete viral control at mucosal reservoirs, reducing transmission risk and improving women’s health outcomes.

The study’s setting in Peru highlights the importance of conducting microbial ecology research across diverse geographic and demographic contexts. Genetic, environmental, sociocultural, and healthcare factors shape host-microbiome and host-virome interactions uniquely in different populations. Understanding these nuances allows for tailored interventions that respect local dynamics while addressing global health challenges.

Another critical aspect underscored by the research is the dynamic nature of cervicovaginal microbial communities over time. This temporal variation demands that assessments and interventions adopt a longitudinal framework rather than single time-point measurements, which may miss transient but clinically significant fluctuations linked to shedding episodes and treatment responses. The integration of longitudinal virome analyses alongside bacterial profiling constitutes a methodological advancement in mucosal immunology research.

Furthermore, the intricate relationships revealed by the study highlight the potential for cross-domain microbial communication influencing HIV pathogenesis. For example, bacteriophages—viruses infecting bacteria—can modulate bacterial competitiveness and biofilm formation, indirectly shaping mucosal environments. Similarly, eukaryotic viruses in the virome may trigger immune activation or suppression, fine-tuning host defenses or inadvertently facilitating viral persistence. This complex network of interactions demands holistic approaches integrating microbial ecology, immunology, and virology.

The authors advocate for expanded research incorporating larger cohorts and mechanistic studies utilizing animal models or in vitro systems to dissect causal links observed in human subjects. Understanding how specific bacterial and viral species mechanistically influence mucosal immunity and HIV reservoirs could inform the development of adjunctive therapies or vaccines optimized for mucosal protection.

In parallel, these findings highlight critical gaps in current HIV management paradigms, particularly in low- and middle-income countries where women bear a disproportionate burden of infection and may face barriers to consistent ART adherence and holistic care. Microbiome-informed interventions could offer low-cost, scalable approaches complementing existing therapies, improving quality of life and reducing transmission.

The new knowledge gained also encourages a reevaluation of HIV transmission risk counseling, considering that genital viral shedding can occur independently of plasma viral load. Incorporating microbial profiling into clinical practice might better stratify transmission risks and guide personalized prevention strategies, such as tailored use of pre-exposure prophylaxis (PrEP) for partners or adjustments in ART regimens.

Finally, the integration of multi-omic technologies to analyze microbial, viral, and host immune factors in a unified framework signifies a significant leap forward in understanding mucosal HIV biology. Employing metagenomics, transcriptomics, and immunoprofiling collectively enables a comprehensive view of the cervicovaginal ecosystem, unraveling previously hidden interdependencies that drive disease processes and therapeutic responses.

This pioneering research thus marks a paradigm shift, emphasizing the necessity of viewing HIV infection and treatment through the lens of complex microbial ecosystems, rather than isolated viral or host factors alone. It opens promising avenues for innovative interventions aimed at harnessing or modulating cervicovaginal microbial communities to achieve sustained viral suppression, minimize shedding, and ultimately curb the global HIV epidemic.

Subject of Research: Longitudinal analysis of cervicovaginal bacteriome and virome dynamics and their association with discordant HIV shedding and antiretroviral therapy duration in women living with HIV.

Article Title: Longitudinal cervicovaginal bacteriome and virome alterations associate with discordant shedding and ART duration in women living with HIV in Peru.

Article References:
Kaelin, E.A., Mitchell, C., Soria, J. et al. Longitudinal cervicovaginal bacteriome and virome alterations associate with discordant shedding and ART duration in women living with HIV in Peru. Nat Commun 16, 7904 (2025). https://doi.org/10.1038/s41467-025-63158-y

Image Credits: AI Generated