''Mycobacteroides'' is a genus of

Gram-Positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bacte ...

rod-shaped bacteria A bacillus (), also called a bacilliform bacterium or often just a rod (when the context makes the sense clear), is a rod-shaped bacterium or archaeon. Bacilli are found in many different taxonomic groups of bacteria. However, the name ''Bacillu ...

in the family ''Mycobacteriaceae'' from the order

Mycobacteriales The Mycobacteriales are an order of bacteria. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online databa ...

. Members of ''Mycobacteroides'' were demarcated from the larger genus ''

Mycobacterium ''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis ('' M. tuberculosis'') and ...

'' in 2018 by Gupta et al. based on evidence from various phylogenetic trees constructed based on conserved genome sequences, comparative genomic analyses and average amino acid identity values. In addition to this genus, the study proposed the division of ''Mycobacterium'' into a total of five distinct genera, which was met with some resistance by some of the scientific community. The resistance was based on the grounds that ''Mycobacterium'' contains some clinically relevant species and name changes might cause confusion among clinicians and other researchers. In 2020, Yamada et al. analyzed the fundamental morphological properties of the new genera, including the cell diameter, cell length, cell perimeter, cell circularity and aspect ratio, and determined that there were significant differences between the five genera, thus supporting the new division. The name ''Mycobacteroides'' is derived from the Latin noun ''Mycobacterium'' (referring to the bacterial genus) and the Latin suffix "-''oides''" (translates to "resembling"). Together the name refers to a genus resembling ''Mycobacterium''.

Biochemical characteristics and molecular signatures

Members of ''Mycobacteroides'' are rapidly growing bacteria, forming colonies in less than seven days. Some characteristics of this genus include: negative for nitrate reductase, iron uptake and demonstrating resistance to polymyxin B. The optimal growth temperature is at 30 °C, although growth can occur at 35 °C. Members also demonstrate a positive result for the 3 day arylsulfatase test. The genome size for ''Mycobacteroides'' species are between 4.5–5.6 Mbp, and their G+C content is between 63.9–64.8 mol%. Some species are pathogenic and demonstrated to be involved in infections of the lung, skin and soft tissues. In addition, some species are also resistant to several antimicrobial drugs. 27

conserved signature indels Conserved signature inserts and deletions (CSIs) in protein sequences provide an important category of molecular markers for understanding phylogenetic relationships. CSIs, brought about by rare genetic changes, provide useful phylogenetic markers ...

(CSIs) were identified as uniquely present in this genus in proteins such as: DEAD/DEAH box helicase, anion transporter, a

membrane protein Membrane proteins are common proteins that are part of, or interact with, biological membranes. Membrane proteins fall into several broad categories depending on their location. Integral membrane proteins are a permanent part of a cell membrane ...

, nicotinate-nucleotide adenylyltransferase, CoA ester lyase,

uracil phosphoribosyltransferase Uracil phosphoribosyltransferase is an enzyme which creates UMP from uracil Uracil () (symbol U or Ura) is one of the four nucleobases in the nucleic acid RNA. The others are adenine (A), cytosine (C), and guanine (G). In RNA, uracil binds t ...

, L-histidine N(alpha)-methyltransferase, DUF58 domain-containing protein, NADH-quinone oxidoreducatase subunit G, ATP-dependent helicase, tRNA (cytidine(34)-2′-''O'')-methyltransferase, glutamine-fructose-6-phosphate transaminase (isomerizing), error-prone DNA polymerase, and 2-amino-4-hydroxy-6-hydroxymethyldihydropteridine diphosphokinase. These molecular signatures were identified through analyses of genome sequences from ''Mycobacteroides'' species and provides a reliable molecular method for distinguishing this genus from the other genera within the family ''Mycobacteriaceae'' and all other bacteria. Additionally, 24 unique conserved signature proteins (CSPs) were identified for this genus. Whole-genome sequencing is the best way to distinguish members of this genus from each other.

Phylogeny

The phylogeny of ''Mycobacteroides'' is based on whole-genome analysis.

References

{{Taxonbar, from=Q107335170 Mycobacteria Bacteria genera