Megasphaera

Abstract Me.ga.sphae'ra. Gr. adj. megas big; Gr. n. sphaera a sphere; N.L. fem. n. Megasphaera big sphere. Anaerobic . Gram‐stain‐negative cocci , 0.4–2.0 µm or more in diameter. Nonmotile. Endospores not formed. Glucose, fructose, and lactate may or may not be fermented. Gas may or may not be produced. Gelatin or milk is not hydrolysed and nitrate is not reduced. Pyruvate but not succinate is utilized. Common metabolic end products of all five species described are acetic, propionic, butyric, and valeric acid. Found in the rumen of cattle and sheep, in the feces and intestine of man, in human clinical samples, and in spoiled bottled beer. DNA G + C content ( mol %): 42.4–46.4 ( T m ), 53.6 (Bd). Type species : Megasphaera elsdenii (Gutierrez, Davis, Lindahl and Warwick 1959) Rogosa 1971a, 187 AL ( Peptostreptococcus elsdenii Gutierrez, Davis, Lindahl and Warwick 1959, 20; organism LC Elsden and Lewis 1953, 183; rumen organism LC Elsden, Volcani, Gilchrist and Lewis 1956, 686). Taxonomic and Nomenclature Notes According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus Megasphaera is: correct name (last update, February 2025) * . LPSN classification: Bacteria / Bacillati / Bacillota / Negativicutes / Veillonellales / Veillonellaceae / Megasphaera The genus Megasphaera can also be recovered in the Genome Taxonomy Database (GTDB) as g__Megasphaera (version v220) ** . GTDB classification: d__Bacteria / p__Bacillota_C / c__Negativicutes / o__Veillonellales / f__Megasphaeraceae / g__Megasphaera * Meier‐Kolthoff et al. ( 2022 ). Nucleic Acids Res , 50 , D801 – D807 ; DOI: 10.1093/nar/gkab902 ** Parks et al. ( 2022 ). Nucleic Acids Res , 50 , D785 – D794 ; DOI: 10.1093/nar/gkab776