''Mycolicibacter'' 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 ''Mycolicibacter'' 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 ''Mycolicibacter'' is derived from the Latin noun ''acidum mycolicum'' (translates to mycolic acid) and the Latin noun ''bacter'' (translates to rod). Together the name refers to a genus of mycolic acid containing rod-shaped bacteria.

Biochemical Characteristics and Molecular Signatures

Members of ''Mycolicibacter'' are slow-growing bacterial species (taking more than seven days to form colonies) and nonchromogenic (does not produce pigment). Some species grow at an intermediate rate, taking 5-15 days to form colonies. While most members of ''Mycolicibacter'' are non-pathogenic, some species have been isolated from animal hosts and human patients. They have a higher G+C content (ranging between 66.3–70.3 mol%) and relatively short genomes between the range of 3.87–5.11 Mbp. Analyses of genome sequences from ''Mycolicibacter'' identified 26

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) that are specific for this genus in the proteins such as non-ribosomal peptide synthetase, nucleoside hydrolase, TetR family transcriptional regulator, carbon starvation protein A, error-prone DNA polymerase,

amidohydrolase Amidohydrolases (or amidases) are a type of hydrolase that acts upon amide bonds. They are categorized under EC number EC 3.5.1 and 3.5.2. Examples include: * Beta-lactamase * Histone deacetylase * Urease Ureases (), functionally, belong to t ...

, carboxymunconolacton decarboxylase family protein, polyketide cyclase, spirocyclase AveC family protein, TobH protein, UDP-N-acetylmuramate–L-alanine ligase, DUF2236 domain-containing protein, cobaltochelatase subunit CobN,

alpha/beta hydrolase The alpha/beta hydrolase superfamily is a superfamily of hydrolytic enzymes of widely differing phylogenetic origin and catalytic function that share a common fold. The core of each enzyme is an alpha/beta-sheet (rather than a barrel), containing ...

, potassium transporter Kef, a membrane protein, DUF222 domain-containing protein, MFS transporter, adenylate/guanylate cyclase domain-containing protein, DUF2029 domain-containing protein and hypothetical proteins. These CSIs provide a reliable molecular method for identifying and distinguishing members of ''Mycolicibacter'' from other genera in the family ''Mycobacteriaceae''. Additionally, 15 unique conserved signature proteins (CSPs) were identified to be specific to most or all members of this genus.

Biochemical Characteristics and Molecular Signatures

Phylogeny

Notes

References