Lactococcus intestinalis sp. nov., a new lactic acid bacterium isolated from intestinal contents in Alzheimer’s disease mice

Abstract

A gram-positive, facultatively anaerobic, and coccoid or ovoid-shaped bacterium designated M2458 T was isolated from the intestinal contents of APP swe /PS ΔE9 mouse model of Alzheimer's disease. With the polyphasic approach, the taxonomic position of the novel isolate was con rmed. Strain M2458 T grew well at 37°C on YCFA agar. Strain M2458 T belongs to the family Streptococcaceae and class Bacilli, and it is related to Lactococcus formosensis NBRC 109475 T (97.59% sequence similarity) according to its 16S rRNA gene sequence. In a comparison of two housekeeping genes, rpoA and rpoB, strain M2458 T was found to be well separated from Lactococcus formosensis NBRC 109475 T . On the basis of whole genome sequences, the DNA G + C content was 38.29 mol%. In terms of average nucleotide identity and digital DNA-DNA hybridization, strain M2458 T was identi ed as a novel species of the genus Lacococcus. The major fatty acids (> 10% of the total fatty acids) were C18:1ω9c (39.68%), C16:0 (13.26%) and C18:1ω7c (11.52%). The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidenti ed phospholipid. As a result of its genotypic and phenotypic characteristics, strain M2458 T was considered to be a new species within the genus Lactococcus; the name Lactococcus intestinalis sp. nov. has been proposed, with type strain M2458 T (= JCM 35706 = CGMCC 1.60066).