- Volume 22, Issue 1, 1972

The biochemical reactions given by 361 strains of herbicolala-thyri bacteria were studied and reported. The microorganisms were categorized into 11 principal biogroups on the basis of reduction of nitrate and their Voges-Proskauer and indole reactions. The taxonomic positions and the nomenclature of the bacteria were discussed in detail, and the microorganisms were classified in the genus Enterobacter as Enterobacter agglomerans (Beijerinck) comb. nov. NCTC 9381 (ATCC 27155; CDC 1461–67) was designated as the neotype strain of the species.

The biochemical characteristics of 137 strains of Citrobacter diversus (Burkey) Werkman and Gillen were determined, and the resulting data are summarized. Members of this species produced indole and ornithine decarboxylase and fermented adonitol but failed to grow in KCN medium. Detectable amounts of hydrogen sulfide were not produced in triple sugar-iron-agar medium but were formed by some strains in peptone-iron-agar. The nomenclature and taxonomic position of these bacteria are discussed, and information that should be helpful for their differentiation from Citrobacter freundii and Enterobacter cloacae is included. Strain 3613–63 (ATCC 27156) is designated as the neotype strain and is described herein.

Sixty-two strains of moraxellae and allied bacteria assembled by the Subcommittee on Moraxella and Allied Bacteria of the International Committee 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 71 biochemical tests. These strains, originally assigned to 11 different genera, were placed in two categories: Acinetobacter and Moraxella. There were 41 strains assigned to Acinetobacter and 19 to 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 carbohydrate-oxidizing 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 this paper, most workers would now agree upon the separation of the oxidase-positive and oxidase-negative organisms with assignment of the former to the genus Moraxella Lwoff and of the latter to the genus Acinetobacter Brisou and Prévot.

The growth characteristics, morphology, and biochemical activity of four strains of a hemolytic, urease-positive, gram-negative organism isolated from vaginal exudate of postparturient sows closely resembled those of organisms belonging to the genus Actinobacillus. Comparison by agglutination, immunodiffusion, and electrophoresis in acrylamide gel revealed that the four strains were identical. They were distinguished from A. lignieresii, A. equuli, A. seminis, A. suis, and other members of the family Brucellaceae by means of these three techniques. The four strains were related antigenically to all strains of the genus Actinobacillus examined, but were related most closely to A. seminis and A. suis. The antigenic relatedness and other similarities support inclusion of the organism in the genus Actinobacillus. Its biochemical, antigenic, and electrophoretic differences from established species of the genus Actinobacillus support the conclusion that this swine actinobacillus is a new species. A species name is not proposed for this organism because of the present uncertain taxonomic status of related actinobacilli. The swine actinobacillus persisted in the vagina of two sows for at least 40 days after intravaginal inoculation; however, proof that vaginal infection with the organism causes urogenital disorders of any type has not been obtained. Intraperitoneal and intravenous inoculation of four 6-week-old colostrum-deprived pigs with the organism resulted in no clinical or postmortem evidence of disease. Strain 192 (= ATCC 27072 = NCTC 10801) is the representative strain of this group of swine actinobacilli.

Mycoplasma arginini Barile et al. 1968 and Mycoplasma leonis Heyward et al. 1969 are regarded as synonyms on the basis of comparisons of the original species descriptions and of the serological and biochemical characteristics of authentic strains, including the type strains, of each of the organisms. According to the rules of nomenclature, the correct name of the species formed by the union of these two taxa is M. arginini Barile et al., which name has priority over M. leonis Heyward et al.