Moraxella atlantae sp. nov. and Its Distinction from Moraxella phenylpyrouvica

Abstract

A homogeneous group of gram-negative, rod-shaped, and oxidase-positive bacterial strains, growing with small colonies, is described. In ordinary culturalbiochemical tests, the entity appeared most similar to Moraxella phenylpyrouvica, although it has so far been distinguished from that species by its simultaneous lack of urease and phenylalanine and tryptophan deaminase activities, inability to grow on solid medium at 4 to 1073, relative salt sensitivity, and different behaviour on bile-containing media. The fatty acid composition was very similar to that of M . phenylpyrouvica, but the organism was distinguishable from the latter in containing a fatty alcohol, n-octadecanol, and mannose. Its genetic affinity to M . phenylpyrouvica and other recognized Moraxella species appeared very low, but was detectable by transformation. The guanine plus cytosine content of its deoxyribonucleic acid was 46.0 to 47.5 mol%, which is 2.5 to 4.0% higher than in M . phenylpyrouuica. The entity is considered a new species of genus Moraxella, and the Moraxella atlantae is proposed.The late Elizabeth 0. King, Communicable Disease Center, Atlanta, Ga., provided us with a number of oxidase-positive, rod-shaped bacterial strains of unknown relation to Moraxella. On genetic and other bases, several of the strains were later allocated to three newly created species, Moraxella osloensis (3, €9, M . phenylpyrouvica (9), and Kingella kingae (11,16,18). The material received from King also contained a group of strains that was urease negative (named group 3 by her; see also reference 24), but was otherwise very similar to urease-positive strains later found to belong to M . phenylpyrouvica. Four strains of her group 3 and a similar strain isolated in Oslo were, in the present study, examined in detail and compared to M. phenylpyrouvica. Initially, the affinities of the strains were studied by genetic transformation and determination of deoxyribonucleic acid (DNA) base composition. Subsequently, the genetically defined groups were compared phenotypically. The genetic transformation experiments included strains of all known species of Moraxella, Kingella, Acinetobacter and several Neisseria species (see Tables 2 and 3). Their mutual genetic relations were studied previously (references of Tables 2 and 3).Genetic transformation. The procedures of mutant selection, preparation of donor DNA, and quantitative transformation with streptomycin resistance as the genetic marker were the same as those used before (7). Resistant mutants were selected in a one-step procedure on blood agar plates a t a concentration of 500 pg/ml of streptomycin. The DNA exposure was terminated after 20 min by deoxyribonuclease. Assay of transformants were performed at a streptomycin concentration of 50 pg/ml, to insure uncritical conditions for phenotypic expression. In addition, the sensitive technique of long-term DNA exposure on plates during growth (7) was used when estimating genetic relationships between species or groups.Determination of DNA base composition. DNA ...

Bacteremia Due to Moraxella atlantae in a Cancer Patient

“…The sequence differences between the two Psychrobacter species amounted to 5.7% as well. The suggestion that these species could be classified as separate genera is in correspondence to earlier reports based on 16S rRNA gene sequencing (8), DNA-DNA hybridization (10), and DNA transformation (2).…”

Acinetobacter , Chryseobacterium , Moraxella , and Other Nonfermentative Gram-Negative Rods

“…On the other hand, pitting is common with M. lacunata, whose colonies are smaller and form dark haloes on chocolate agar. Rod-shaped Moraxella species, especially M. atlantae and M. lincolnii, are more fastidious and display smaller colonies on SBA, less than 1 mm in diameter after 24 h. Colonies of M. atlantae are small (usually 0.5 mm in diameter) and show pitting and spreading (24). The growth of M. atlantae is stimulated by bile salts, which explains its growth on MacConkey agar.…”

Free-living psychrophilic bacteria of the genusPsychrobacterare descendants of pathobionts

“…P-clade Moraxella have more similar phenotypes compared to M-clade Moraxella than to Psychrobacter strains. Review of type strain descriptions revealed that Psychrobacter are consistently urease positive, nitrate reducing, salt tolerant, and non-fastidious, whereas P-clade Moraxella are inconsistent with their urease and nitrate reducing phenotypes, are sensitive to high salt concentrations, andare often nutritionally fastidious -they have complex growth requirements (in particular, often blood or bile for growth)[23,24,39,42,50,51,66,67].…”