No abstract

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Sixty-two strains of moraxellae and allied bacteria assembled by the Subcommittee on Moraxella and Allied Bacteria of the International Commit tee on Systematic Bacteriology and distributed by the American Type Culture Collection were examined serologically by the fluorescent-antibody (FA) and quellung techniques and subjected to study using 7 1 biochemical tests. These strains, originally assigned t o 11 different genera, were placed in two categories: Acinetobacter and Moraxella. There were 4 1 strains assigned t o Acinetobacter and 19 t o Moraxella. Two strains were eliminated from the study. One strain belonged to neither of these genera; the other was eliminated on the basis of colonial and biochemical variability. Sixty per cent of the carbohydrateoxidizing strains of Acinetobacter were typable by FA and quellung reaction in conjugates and sera prepared from oxidizing strains. The capsular antigens of the oxidizers (formerly called Herellea) are distinctly different from those of the nonoxidizers (formerly called Mima). A small percentage of the nonoxidizing cultures exhibited cross-reactions with antibodies for the oxidizers. None of the moraxellae were typable with conjugates or antisera for the oxidizing acinetobacters. The results of these studies were correlated with those of other workers. In general, the classification of the bacteria discussed in this report was quite reliable when based on the use of seven selected phenotypic characteristics. This fact has practical diagnostic importance. The true relationships and taxonomic placements of the moraxellae and allied bacteria are dependent upon the development and employment of systems for genetic analysis. On the basis of studies reviewed in thls paper, most workers would now agree upon the separation of the oxidase-positive and oxidase-negative organisms with assignment of the former t o the genus Moraxella Lwoff and of the latter to the genus Acinetobacter Brisou and PrCvot.

Pseudomonas acidovorans can be distinguished from P. testosteroni by gas chromatography on the basis of acids detected after 20 h growth on heart infusion agar plates. The data obtained support the findings of other workers that P. acidovorans and P. testosteroni are two different species and indicate that gas chromatography may be used effectively to distinguish other members of the genus.

A total of 109 cultures of Pseudomonas putrefaciens isolated from clinical specimens were studied. The cultures were separated into two groups. The majority of the group 1 isolates, comprising 31 cultures, were characterized by (i) growth in plain nutrient broth, but no growth in broth supplemented with NaCl at concentrations of 7% and above, (ii) no growth on Salmonella-Shigella (SS) agar, and (iii) production of acid from the carbohydrates, sucrose, maltose, arabinose, and dextrin. Most group 2 isolates, comprising 78 cultures, were (i) unable to grow in plain nutrient broth, but grew well in broth supplemented with NaCl at a concentration of 7 to 10%, (ii) able to grow on SS agar, and (iii) unable to produce detectable amounts of acid from any of the carbohydrates tested except for variable results with glucose and fructose.