Bacilli

Bacilli is a taxonomic class of bacteria that includes two orders, Bacillales and Lactobacillales, which contain several well-known pathogens such as Bacillus anthracis (the cause of anthrax). Bacilli are almost exclusively gram-positive bacteria.[1]

This article is about the bacterial class. For the genus, see Bacillus. For rod-shaped bacteria in general, see bacillus (shape).

Bacilli
Bacillus subtilis, Gram stain
Scientific classification
Domain:	Bacteria
Phylum:	Firmicutes
Class:	Bacilli Ludwig et al. 2010
Orders
Bacillales Alicyclobacillaceae Bacillaceae Listeriaceae Paenibacillaceae Pasteuriaceae Planococcaceae Sporolactobacillaceae Staphylococcaceae Thermoactinomycetaceae Lactobacillales Aerococcaceae Carnobacteriaceae Enterococcaceae Lactobacillaceae Leuconostocaceae Streptococcaceae

Ambiguity

Several related concepts make use of similar words, and the ambiguity can create considerable confusion. The term "Bacillus" (capitalized and italicized) is also the name of a genus (Bacillus anthracis) that, among many other genera, falls within the class Bacilli.

The word "bacillus" (or its plural "bacilli", with a small b) is also a generic term to describe the morphology of any rod-shaped bacterium. This general term does not mean that the subject is a member of class Bacilli or genus Bacillus. Thus, it does not necessarily imply a similar group of characteristics. Not all members of class Bacilli are rod-shaped (Staphylococcus is spherical), and many other rod-shaped bacteria that do not fall within that class exist (e.g., Clostridium is rod-shaped but very different taxonomically). Moreover, the general term "bacillus" does not necessarily indicate the Gram-positive staining common to class Bacilli. For example, E. coli is a rod-shaped bacterium that can be described as "a bacillus", but it stains Gram-negative and does not belong to the genus Bacillus or the class Bacilli. Some microbiologists have forsaken the general "bacillus" term because of the confusion it can create.

Phylogeny

The phylogeny is based on 16S rRNA-based LTP release 132 by The All-Species Living Tree Project,[2] with the currently accepted taxonomy based on the List of Prokaryotic names with Standing in Nomenclature (LPSN),[3] National Center for Biotechnology Information (NCBI)[4] and some non validated clade names from Genome Taxonomic Database.[5]

Bacilli

Calditerricola {"Calditerricolales" ♥: "Calditerricolaceae" ♥}     Kyrpidia {"Kyrpidiales" ♥: "Kyrpidiaceae" ♥}         Thermoactinomycetaceae {"Thermoactinomycetales" ♥}       Caldalkalibacillus {"Caldalkalibacillales" ♥: "Caldalkalibacillaceae" ♥}     Thermicanales ♥   "Thermicanaceae" ♥     "Novibacillaceae" ♥         "Tumebacillales" ♥   "Effusibacillaceae" ♥     "Tumebacillaceae" ♥     "Alicyclobacillales" ♥   "Acidibacillaceae" ♥     Alicyclobacillaceae         "Paenibacillales" ♥   Ammoniibacillus     Paenibacillaceae         Microaerobacter       "Tepidibacillaceae" ♥ {"Tepidibacillales" ♥}       Melghiribacillus       Bacillus species group 2         "Salisediminibacteriaceae" ♥     "Marinococcaceae" ♥         Bacillaceae 2       "Amphibacillaceae" ♥       Aureibacillus         "Fictibacillaceae" ♥       Sporolactobacillaceae     "Anaerobacillaceae" ♥         (continued)

Bacilli part 2 (continued)

Bacilli part 2

Bacillaceae (incl. Planococcaceae) {Bacillales}         "Domibacillaceae" ♥     "Anoxybacillaceae" ♥           Bacillus koreensis     Listeriaceae         Desulfuribacillus         Exiguobacterium {"Exiguobacterales" ♥: "Exiguobacteraceae" ♥}       Paenibacillaceae 2       Aneurinibacillus {"Aneurinibacillales" ♥: "Aneurinibacillaceae" ♥}     Brevibacillus {"Brevibacillales" ♥: "Brevibacillaceae" ♥}             Staphylococcaceae         Gemella   Aphragmobacteria   Haloplasma contractile       Turicibacter sanguinis         Asteroleplasma     Eggerthiaceae {Eggerthiales}         Erysipelotrichaceae {Erysipelotrichales}   Mollicutes     Anaeroplasma {Anaeroplasmataceae}     Acholeplasma {Acholeplasmatales: Acholeplasmataceae}     Mycoplasmatales   Mycoplasmataceae (incl. Entomoplasmataceae; Spiroplasmataceae)     Ureaplasmataceae                 Lactobacillales   Aerococcaceae       Granulicatella       Atopobacter       Carnobacteriaceae 2       Carnobacteriaceae+Enterococcaceae+Streptococcaceae       Lactobacillus species-group 2         Lactobacillus floricola     Leuconostocaceae       Lactobacillaceae

Unclassified Bacilli

• "Candidatus Izimaplasma" ♠ {"Izimaplasmatales" ♥: "Izimaplasmataceae" ♥}
• "Candidatus Lumbricoplasma" ♠ {Lumbricoplasmataceae ♠}
• "Rubeoparvulaceae" ♥ {"Rubeoparvulales" ♥}

Notes:
♥ Clade names not lodged at National Center for Biotechnology Information (NCBI) or listed in the List of Prokaryotic names with Standing in Nomenclature (LPSN)

References

1. Ludwig, Wolfgang; Schleifer, Karl-Heinz; Whitman, William B. (2015). "Bacilli class. Nov". Bergey's Manual of Systematics of Archaea and Bacteria. p. 1. doi:10.1002/9781118960608.cbm00033. ISBN 9781118960608.
2. "16S rRNA-based LTP release 132 (full tree)". All-Species Living Tree Project. Silva Comprehensive Ribosomal RNA Database. Retrieved 2018-07-20.
3. J.P. Euzéby. "Bacilli". List of Prokaryotic names with Standing in Nomenclature (LPSN). Retrieved 2018-07-20.
4. Sayers; et al. "Bacilli". National Center for Biotechnology Information (NCBI) taxonomy database. Retrieved 2018-07-20.
5. "GTDB taxonomy". Genome Taxonomic Database. Archived from the original on 2018-07-29. Retrieved 2018-07-20.