Table 1.

Distribution of spore-forming bacteria among Firmicutes

Class, ordera	Familya	Complete genomes, speciesb	Spore-formers in the set	Non-sporogenic members of spore-forming clades (examples)
Bacilli
Bacillales	Bacillaceae	29	28	Bacillus selenitireducens
	Listeriaceae	5	None
	Paenibacillaceae	7	7
	Staphylococcaceae	8	None
	Other	5	3	Exiguobacterium sibiricum
Lactobacillales	Lactobacillaceae	21	None
	Leuconostocaceae	7	None
	Streptococcaceae	18	None
	Other	5	None
Clostridia
Clostridiales	Clostridiaceae	19	17	Clostridium sp. SY8519c
	Eubacteriaceae	3	None
	Peptococcaceae	12	11	Filifactor alocis
	Other	16	6	Finegoldia magna
Halanaerobiales	Halobacteroidaceae	4	None
Thermoanaero bacterales	Thermoanaerobacte raceae	12	10	Ammonifex degensii
	Family III Incertae Sedis	8	None
	Other	6	4	Coprothermobacter proteolyticusd
Erysipelotrichi	Erysipelotrichaceae	1	None
Negativicutes	Veillonellaceae, Acidaminococcaceae	4	None
Mollicutesa	Acholeplasmataceae, Mycoplasmataceae	27	None

^a.Taxonomy is according to the NCBI Taxonomy database (Federhen, 2012) and the ribosomal proteins-based tree (Ciccarelli et al., 2006; Yutin et al., 2012), which are generally consistent with the Bergey's Taxonomic Outline (Ludwig et al., 2009). Negativicutes have been recently recognized as a separate class (Marchandin et al., 2010), whereas Mollicutes were re-classified into a separate phylum Tenericutes (Ludwig et al., 2009). See Table S1 for the complete list.

^b.As of the end of 2011; based on a non-redundant set that includes a single representative genome for each individual species.

^c.The second genome of non-sporulating member of Clostridiaceae is that of C. tetani E88, a non-sporulating variant of strain Massachusetts used in vaccine production (Brüggemann et al., 2003).

^d.Placing of Coprothermobacter proteolyticus within Clostridia is not supported by either ribosomal protein-based phylogeny (Yutin et al., 2012) or whole-genome analysis (Beiko, 2011; Nishida et al., 2011).