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The in-vitro effect of EDTA-Tris-lysozyme solution on 16 pathogenic bacteria of medical or veterinary importance was determined. Marked decreases in bacterial count occurred with Pseudomonas aeruginosa, Escherichia coli, Moraxella osloensis and Campylobacter fetus, and smaller decreses with Salmonella typhimurium, Shigella boydii, Aeromonas hydrophila, proteus mirabilis, Listeria monocytogenes and Erysipelothrix insidiosa. The test solution had no effect on Klebsiella ozaenae, Brucella canis, Cornynebacterium pyogenes, Coryne, renale, Streptococcus equi and staphylococcus aureus.

Gentisate:oxygen 1,2-oxidoreductase (decyclizing) (EC 1.13.11.4; gentisate 1,2-dioxygenase) from Moraxella osloensis was purified to homogeneity as shown by polyacrylamide gel electrophoresis. The enzyme has a molecular weight of about 154,000 and gives rise to subunits of molecular weight 40,000 in the presence of sodium dodecyl sulfate. Gentisate 1,2-dioxygenase showed broad substrate specificity and attacked a range of halogen- and alkyl-substituted gentisic acids. Maleylpyruvate, the product formed from gentisate, was degraded by cell extracts supplemented with reduced glutathione, but substituted maleylpyruvates were not attacked under these conditions.

A genetic transformation assay for unequivocal identification of strains of Moraxella osloensis is described. In this assay a stable tryptophan auxotroph is transformed to prototrophy by deoxyribonucleic acid (DNA) samples from other strains of M. osloensis but not by DNA samples from unrelated bacteria. The test is simple to perform and definitive results can be obtained in less than 24 h. The procedure, which is suitable for routine diagnosis in a clinical laboratory, involves a rapid method for preparation of crude transforming DNA from small quantities of bacterial cells and permits simultaneous examination of large numbers of isolated cultures. The assay was shown to correctly identify 27 strains previously classified as M. osloensis . Forty-five other gram-negative, oxidase-positive, nonmotile coccobacilli, which might be confused with M. osloensis unless subject to more extensive testing, were shown to be unrelated genetically to M. osloensis . The transformation assay clearly distinguishes M. osloensis from Acinetobacter . Although most strains of M. osloensis are nonfastidious, being able to grow in a mineral medium supplemented with a single organic carbon source, one of the strains tested was only able to grow on fairly complex media and could not be transformed to grow on simple media. Inability to alkalize Simmons citrate agar was shown not to be characteristic of all strains of M. osloensis .

Organisms corresponding to the description of Moraxella nonliquefaciens can be subdivided into several taxa. A subgroup with comparatively fastidious growth requirements is retained in the species M. nonliquefaciens, and a revised description of this species is given. The strain 4663/62 is proposed as a neotype strain. A second, more robust subgroup is described and given the name M. osloensis. The strain A 1920 is designated as the type strain. The use in taxonomy of such criteria as DNA base composition and compatibility in transformation is briefly discussed.

Es wird uber einen Fall von eitriger Meningitis durchMoraxella osloensis bei einem 4 1/4jahrigen Jungen berichtet. Trotz der geringen Empfindlichkeit des Erregers wurde das Kind mit Penicillin (und anschliesend Chloramphenicol) komplikationslos geheilt. Fur die bakteriologische Diagnose der Meningitis ist die Bestimmung der biochemischen Eigenschaften des Erregers unerlaslich; der Nachweis gramnegativer, oxidasepositiver Diplokokken reicht dafur nicht aus.

The biochemical characteristics of 59 strains of Moraxella urethralis from clinical specimens, primarily from urine and the female genital tract, were studied. The characteristics included (i) the inability to acidify carbohydrate substrates, (ii) the ability to produce phenylalanine deaminase, (iii) the ability to reduce nitrite, (iv) the lack of urease activity, and (v) the ability of most strains to alkalinize citrate. A means of differentiating M. urethralis from Moraxella osloensis and Moraxella phenylpyruvica was determined.

Ground beef contains numerous microorganisms of various types. The commonly recognized bacteria are associated with current problems of spoilage. Irradiation, however, contributes a new factor through selective destruction of the microflora. The residual microorganisms surviving a nonsterilizing dose are predominantly gram-negative coccobacilli. Various classifications have been given, e.g., Moraxella, Acinetobacter, Achromobacter , etc. For a more detailed study of these radiation-resistant bacteria occurring in ground beef, an enrichment procedure was used for isolation. By means of morphological and biochemical tests, most of the isolates were found to be Moraxella , based on current classifications. The range of growth temperatures was from 2 to 50 C. These bacteria were relatively heat sensitive, e.g., D 10 of 5.4 min at 70 C or less. The radiation resistance ranged from D 10 values of 273 to 2,039 krad. Thus, some were more resistant than any presently recognized spores. A reference culture of Moraxella osloensis was irradiated under conditions comparable to the enrichment procedure used with the ground beef. The only apparent changes were in morphology and penicillin sensitivity. However, after a few subcultures these bacteria reverted to the characteristics of the parent strain. Thus, it is apparent that these isolates are a part of the normal flora of ground beef and not aberrant forms arising from the irradiation procedure. The significance, if any, of these bacteria is not presently recognized.

A number of strains of oxidase-positive moraxellas and of neisserias related to Neisseria catarrhalis were characterized with respect to a number of nutritional and physiological properties and could be assigned to several species or species groups on the basis of their phenotypic traits. This grouping was consistent with that established by Bövre on the basis of transformation frequencies for streptomycin resistance. It is proposed to reserve the generic name Moraxella for the oxidase-positive rodshaped organisms, and a redescription of the genus is offered. Following the recent taxonomic proposals of Bövre and Henriksen, the specific name Moraxella osloensis is applied to the nutritionally unexacting strains that accumulate poly-β-hydroxybutyrate as carbon reserve. The nutritionally exacting strains are assigned to three distinct groups which can be regarded as separate species or as varieties of M. lacunata . The epithets applicable to these groups appear to be lacunata, nonliquefaciens , and bovis . The “false neisserias” could be assigned to at least three subgroups, one of which constitutes the clearly defined entity, N. catarrhalis , which could be distinguished from N. caviae and N. ovis .

More than 90 morphological and physiological characters of 546 strains of nonfermentative, nonfastidious, Gram negative bacteria isolated from clinical specimens were examined to determine those features most useful for the identification of these bacteria. The species examined included Moraxella osloensis, Mor. lacunata, Acinetobacter anitratum, Ac. haemolyticus subsp. haemolyticus, Ac. haemolyticus subsp. alcaligenes, Ac. Iwoffi, Alcaligenes faecalis, Alc. odorans var. viridans, Pseudomonas fluorescens, Ps. putida, Ps. pseudomallei, Ps. maltophilia, Ps. stutzeri, Ps. acidovorans, Ps. alcaligenes, and atypical strains of Ps. aeruginosa.

Summary The first case of septic arthritis associated with vaginal discharge in a young child caused by Moraxella osloensis is reported. The similarity of clinical appearance to gonococcal disease and of microscopic morphology of the organism to Neisseria gonococcus emphasize the necessity for confirming a suspected clinical diagnosis with careful laboratory studies.