Characterization and Profiling of Gut Bacterial Microbiome and Pathobionts among HIV-negative and HIV-infected Individuals in Cameroon

Background: Knowledge of the core gut microbiome among Cameroonians is a preliminary step for a better implementation of treatment strategies to correct dysbiosis and improve health care management. HIV infection has continued to cause high mortality among those infected, but the types and frequency of human gut microbiota associated with or without HIV/AIDS presence have not been identified in the adult populations in Cameroon.

Methods: This was a case-control and comparative study design that ran from June 2018 to September 2019. Stool Samples were purposively collected from 40 participants (15 HIV-negative and 25 HIV-positive) for the 16S rRNA gene sequencing on the next-generation Illumina® MiSeq™ sequencer. Blood samples were collected for HIV determine testing, CD4 Tcell count, and HIV viral load. Sequences were clustered into operational taxonomic units (OTUs) at ninety-nine percent identity and their representatives were accustomed to using a phylogenetic approach.

Results: The study showed a phylogenetic taxonomy of the gut microbiome communities in two kingdoms (Archea and Bacteria) and eight Phylum [Firmicutes (44.7%), Bacteroidetes (43.7%), Proteobacteria (8.7%), Actinobacteria (1%), Fusobacteria (0.2%), Euryarchaeota (0.01%), Synergistetes (0.01%), Verrucomicrobia (0.01%) and unclassified phylum (1.7%)]. A total of 347 gut microbiota species were identified, including 55 unique species/oligotypes, and 28 pathobionts from the study population. HIV infection was characterized by significant gut microbiota compositional changes with HIV-positive less diverse (56 strains absent) with significantly increased OTUs of the butyrate-producing microbiome species as compared to HIV-negative individuals (p=0.001).

Conclusions: A profile of 347 gut microbiome bacterial species was identified in the Cameroonian community. Particularly, from the 347 gut microbiome bacterial species profiled, eight phyla were identified, with 55 unique species/oligotypes containing more than one sequence and 28 pathobionts. A host of unknown/unclassified gut microbiome bacterial species were also noted circulating among the study population.