Moraxella atlantae

Moraxella atlantae is a Gram-negative, oxidase-positive and catalase-positive, rod-shaped, nonmotile bacterium in the genus Moraxella. First described in 1976 it was recognized as a rare opportunistic pathogen in humans starting in 1991.

Taxonomy and microbiological characteristics
Moraxella atlantae was first described as a new species in 1976 based on biochemical and microbiological growth characteristics: It resembled Moraxella phenylpyruvica, but differed in "simultaneous lack of urease and phenylalanine and tryptophan deaminase activities, inability to grow on solid medium at 4 to 10°C, relative salt sensitivity, and different behaviour on bile-containing media." In difference it also contains n-octadecanol and mannose. It is a non-fermenter and has been difficult to identify by biochemical phenotypic characteristics, like API. It was previously known as CDC group M-3. In 2008, the Judicial Commission of the International Committee for Systematics of Prokaryotes ruled that a subgenus name of Moraxella atlantae (subgen. Moraxella Lwoff 1939)) should have been included on the Approved Lists of Bacterial Names, but in 2014 this was rescinded.

Infections in humans
M. atlantae was first recognized as a rare opportunistic pathogen in humans in 1991, when it was isolated from the blood culture of a person with SLE. In a case report from 2002 it was isolated from aerobic blood cultures from a female cancer patient, and could not be identified based on phenotypic characteristics and Analytical profile index, but only after 16S rRNA gene amplification. It was then identified in 2016 and in 2017 in one patient each with pneumonia and bacteremia.

In 2017, it was described as causing keratitis in one case. A 2018 case report from Spain described it in the native aortic valve of a butcher with infective endocarditis without apparent risk factors.

Frequency of isolation
As of 2002, the University of Göteborg had collected only 12 M. atlantae strains, 10 of which had been isolated since 1981, of which most were from blood (10), and only one from pleural fluid, and one from a dog bite wound each.

Treatment of infections
M. atlantae can usually be treated by common antibiotics.