Further dissection of Gardnerella vaginalis: description of Gardnerella lacydonensis sp. nov. (formerly genomic species 2), Gardnerella bretellae sp. nov. (formerly genomic species 9), Gardnerella massiliensis sp. nov. (formerly genomic species 14) a

Four bacterial strains - Marseille-Q9181^T, Marseille-QA0894^T, Marseille-Q9179^T and Marseille-Q2328^T - were isolated, the first three from vaginal samples and the last from a blood sample. MALDI-TOF MS analysis failed to assign these isolates to any known species within the genus <i>Gardnerella</i>. Consequently, phenotypic and taxonogenomic characterizations were conducted. All four strains were Gram-negative, non-motile and non-spore-forming coccobacilli. Strains Marseille-Q9181^T, Marseille-Q2328^T and Marseille-Q9179^T were facultative anaerobes with microaerophilic capabilities, whereas Marseille-QA0894^T was strictly anaerobic and microaerophilic. The dominant fatty acids (>10%) identified in strains Marseille-Q9181^T, Marseille-QA0894^T and Marseille-Q2328^T were C_{16 : 0}, C_{18 : 1} ω9c and C_{18 : 0}. In strain Marseille-Q9179^T, C_{18 : 0} was also among the most abundant fatty acids, along with the aforementioned three. Digital DNA-DNA hybridization (dDDH) values for strains Marseille-Q9181^T, Marseille-QA0894^T and Marseille-Q2328^T against <i>Gardnerella vaginalis</i> 1400E (genomic species 2), <i>G. vaginalis</i> 6119V5 (genomic species 9) and <i>G. vaginalis</i> NR010 (genomic species 14) were 72.1%, 72.4% and 75.5%, respectively. The corresponding OrthoANI values were 96.99%, 97.16% and 97.66%, all above the species demarcation threshold. In contrast, strain Marseille-Q9179^T exhibited both dDDH and OrthoANI values below the accepted thresholds (70% and 95-96%, respectively), suggesting that it represents a novel genomic lineage. Based on comprehensive phenotypic and genomic analyses, we propose that these strains represent four new species within the genus <i>Gardnerella</i>, for which the following names are proposed: <i>Gardnerella lacydonensis</i> sp. nov. (type strain: Marseille-Q9181^T=CSUR Q9181^T=CECT 31121^T), <i>Gardnerella bretellae</i> sp. nov. (type strain: Marseille-QA0894^T=CSUR QA0894^T=CECT 31122^T), <i>Gardnerella massiliensis</i> sp. nov. (type strain: Marseille-Q2328^T=CSUR Q2328^T=CECT 30239^T) and <i>Gardnerella phocaeensis</i> sp. nov. (type strain: Marseille-Q9179^T=CSUR Q9179^T=CECT 31120^T).