Unveiling the Intricate Link Between Anaerobe Niche and Alzheimer Disease Pathogenesis.

This article focuses on the role of anaerobic bacterial niches associated with the brain and their potential links to Alzheimer disease (Ad) pathology. It reviews evidence of microbial dysbiosis—imbalances in microbiome communities—in various anaerobic environments near the brain, including oral periodontal pockets, gut microbiota, cerebral atherosclerotic plaques, brain abscesses, and corpora amylacea, highlighting bacteria such as *Porphyromonas gingivalis* and *Escherichia coli* that are found at increased levels in Ad brains. While associations between bacterial infections and increased risk of Ad have been observed, causative mechanisms remain unconfirmed, and further research using animal models and advanced microbial characterization is needed. The review underscores the importance of investigating these anaerobic niches to better understand microbial contributions to Ad and to explore potential diagnostic and therapeutic strategies.