lactobacillusdominated

Lactobacillusdominated refers to a microbial community in which species of the genus Lactobacillus constitute the majority of bacteria present. In practice, it is defined by a relative abundance that exceeds a site-specific threshold, often around half or more of the community, though exact cutoffs vary by habitat and methods. The term is descriptive rather than taxonomic, used to characterize community composition in metagenomic or 16S rRNA sequencing data.

It is a characteristic feature of many healthy vaginal ecosystems, where several community-state types are described. Lactobacillusdominated vaginal microbiota are typically enriched in species such as L. crispatus, L. gasseri, L. jensenii, or L. iners, and are associated with low pH and protection against pathogens. Lactobacillusdominated profiles also occur, less commonly, in the gut of some individuals, in the oral cavity, or in fermented foods and probiotic preparations.

Functional role of Lactobacillusdominated communities includes the production of lactic acid to acidify the environment, and the generation of antimicrobial compounds such as hydrogen peroxide and bacteriocins, which help suppress pathogenic microbes and support stable ecosystems. However, dominance by a single genus may coincide with reduced microbial diversity and resilience. For example, in the vagina, L. iners-dominated states can be more transitional and linked to instability or higher risk of dysbiosis under certain conditions.

Measurement and interpretation rely on sequencing approaches to detect Lactobacillusdominated communities. Interpreting results requires consideration of body site, age, hormonal status, recent antibiotic use, and the presence of co-dominant species. The concept is useful for describing shifts in microbiota but should not be interpreted as a universal marker of health for all sites.

See also: vaginal microbiome, community-state types, probiotic Lactobacillus.