Brackiella oedipodis gen. nov., sp. nov., Gram-negative, oxidase-positive rods that cause endocarditis of cotton-topped tamarin (Saguinus oedipus)

Researchers isolated an unknown Gram-negative, oxidase-positive, rod-shaped bacterium from the heart of a deceased cotton-topped tamarin (Saguinus oedipus) at a German primate research center. The animal had died suddenly during a tooth extraction and showed evidence of chronic epicarditis and endocarditis. Through comprehensive characterization including 16S rDNA sequencing, protein analysis, fatty acid profiling, and biochemical testing, the organism was determined to represent a novel genus and species within the β-Proteobacteria. It is most closely related to Taylorella, Pelistega, Bordetella, Alcaligenes, and Achromobacter genera but forms a separate phylogenetic line. The bacterium is non-motile, coccoid, surrounded by fimbriae, aerobic to microaerophilic, and grows optimally at 30-37°C. The researchers designated it Brackiella oedipodis, representing the first documented case of endocarditis caused by a member of this phylogenetic group. The source and transmission route remain unknown, though the infection was discovered postmortem during routine necropsy examination.

Key findings

• A novel genus and species, Brackiella oedipodis, was identified from heart tissue of a dead cotton-topped tamarin with endocarditis
• The bacterium is a non-motile, Gram-negative, oxidase-positive coccoid rod within the β-Proteobacteria, phylogenetically distinct from but related to Alcaligenes, Bordetella, Taylorella, and other genera
• This is the first documented case of endocarditis caused by a member of the Alcaligenaceae phylogenetic group or related taxa
• The organism produced iron-regulated outer-membrane proteins typical of iron-transport systems but did not produce detectable siderophores
• The bacterium was susceptible to all 17 antimicrobial agents tested, including common antibiotics