Bordetella trematum

Bordetella trematum is a species of Gram-negative bacteria identified in 1996 by comparison of 10 strains of "B. trematum" against other well characterized "Bordetella" and "Alcaligenes" species. The term "trema" refers to something pierced or penetrated, or to a gap. "Trematum" pertains to open things, and refers to the presence of bacteria in wounds and other exposed parts of the body. Strain LMG 13506T is the reference strain for this species.
Isolation.
"Bordetella" species typically infect the respiratory tracts of humans, but "B. trematum" has never been isolated from a human or animal respiratory tract. It has been isolated from human ear infection and limb wounds. Below is a list of known "B. trematum" strains, alternative strain designation, and the date and source where they were first isolated:
Characteristics.
"Bordetella trematum" is a Gram-negative, capsulated, non-spore-forming, rod about 0.5 μm wide and 1.0-1.8 μm long, but rods as long as 2.4 μm have been observed. It grows aerobically at temperatures ranging from 25-42 °C, with optimal temperature for growth ranging from 35-37 °C. Microaerobic growth may be observed at optimal temperatures. It is motile via peritrichous flagella. "B. trematum" is catalase positive. It is unique in being oxidase negative, since all other species of "Bordetella" are oxidase positive.
"Bordetella trematum" may be cultured on horse blood agar, MacConkey agar, and Bordet–Gengou agar. When grown on Bordet–Gengou agar, which is the standard agar for "Bordetella" isolation, colonies are convex, pearly, smooth, almost transparent, and glistening, and are surrounded by a zone of hemolysis. When grown on blood agar, colonies are grayish cream to white, circular, and convex.
Metabolism.
Little is known about the metabolism of the species "B. trematum" since it is relatively newly discovered. Like all "Bordetella" species, "B. trematum" is a chemoorganotroph and requires nicotinamide, organic sulfur such as cysteine, and organic nitrogen such as amino acids for growth by respiratory metabolism. Its metabolism is not saccharolytic, meaning it does not use any form sugar for energy. Six of the ten known strains are able to reduce nitrate to nitrite. It is indole negative and urease negative.
Taxonomy.
DNA-rRNA hybridization was used to place "B. trematum" LMG 13506T in the family Alcaligenaceae. Amplified ribosomal DNA restriction analysis revealed a 94% similarity between the "B. trematum" reference strain and the" Bordatella" reference species, "B. pertussis". Later, additional evidence to determine placement at the genus level came from DNA-DNA hybridization of "B. trematum" strains LMG 13506 and LMG 14446 against reference strains of other "Bordetella" and "Alcaligenes" species. Results showed the species "B. trematum" to be most like members of the genus "Bordetella". SDS-PAGE analysis of whole-cell proteins allowed for development of a dendrogram displaying that "Bordetella" is not monophyletic. DNA-rRNA hybridization and 16S rRNA sequence analysis shows a close relationship between "Bordetella" and "Alcaligenes". It is often difficult to differentiate between the two genera; in fact, some species across the genera are phenotypically identical.
"Bordetella trematum" and "B. holmesii" are the only species that do not colonize the respiratory tract. "B. pertussis" and "B. parapertussis" are respiratory pathogens that cause pertussis. "B. bronchiseptica" and "B. avium" are respiratory pathogens of other animals. "B. hinzii" is not pathogenic and colonizes the respiratory tract of birds. "B. holmesii" has been isolated from human blood. Members of the genus "Alcaligenes" colonize humans, but not the respiratory tract, and soil and water.
Genomics.
The "B. trematum" genome was sequenced in 2013, and is currently undergoing annotation. The genome is estimated to possess 4,145 coding sequences with the majority of sequences coding for amino acids, amino acid derivatives, and carbohydrate pathways. About 184 genes are predicted to be involved in membrane transport. It has a 64-65% GC content. The total genome size is not currently known.
Pathogenicity.
"Bordetella trematum" is a nonpathogenic, opportunistic organism whose sole source of isolation is open, human wounds. It can be ridded from the body without medical intervention.
"Bordetella" endotoxins are unique to the genus, species, and strain. "B. trematum" is the only "Bordetella" species with a semirough lipopolysaccharide which contains a single O-unit. The lipid A unit of "B. trematum" is identical to that of the opportunistic bacterium "B. hinzii", but unlike any other "Bordetella" species.