1887

Abstract

Summary:A computer survey was made to find the relationships of 120 strains of Gram-negative or Gram-variable non-motile coccoid rods, isolated by the author and formerly called They were compared with 75 named strains of various Gram-negaiive genera, on the basis of morphological properties and biochemical tests. A recently developed similarity coefficient was used and strainswere sorted into phenons by single linkage. Most of the strains were grouped at 72·5% similarity into one large phenon. Strains outside this phenon were: These were differentiated from the 72·5-phenon by various combinations of the following characters which were nearly always negative for strains within the phenon: fermentative metabolism of sugars, pigmentation, production of reducing compounds from gluconate, alkalinity from arginine, hydrolysis of starch or proteins.

Within the 72·5-phenon, five smaller phenons were distinguished, most of them grouped at 82·5% similarity. The strains in each of these phenons and the characters possessed by a majority of strains and useful for the differentiation of these phenons were:

were Gram-negativemotile rods, usually peritrichous.

Acid was produced oxidatively from glycerol, sucrose, fructose, lactose, arabinose, xylose, galactose and glucose; HS produced in Kligler medium; the Kovacs oxidase test positive; nitrate reduced; growth on Simmons medium and on Paton medium; no growth on digest agar at 0° or 37°; not sensitive to 2·5 i.u. of penicillin.

Acid not produced from sugars; oxidase-positive; nitrate reduced; growth on Simmons medium; no growth on Paton medium; growth on digest agar at 37° but not at 0°; litmus milk became alkaline; not sensitive to 2·5 i.u. of penicillin.

were Gram-negative coccoid rods, cocci or short sods, often in pairs.

MJT isolate (I). Acid not produced from glycerol, sucrose or fructose; oxidative acid production from lactose, arabinose, xylose, galactose and glucose; oxidase-negative; nitrate not reduced; growth on Simmons medium and on Paton medium; growth on digest agar at 37° but not at 0°; litmus milk became acid; not sensitive to 2°5 i.u. of penicillin.

MJT isolates (22). Acid not produced from glycerol, sucrose or fructose; oxidative acid production from lactose, arabinose, xylose, galactose and glucose; oxidase-positive; nitrate reduced; no growth on Simmons or Paton media; growth on digest 0° at oc but not at 37°; no pH change in litmus milk; sensitive to 2°5 i.u. of penicillin.

MJT isolates (93). Acid not produced from sugars; no growth on Simmons medium; growth on digest agar at 0° but not at 37°; no pH change in Iitnius milk; sensitive to 2°5 i.u. of penicillin. Other characters variable.

small phenons grouped at about 92°5:% similaritywithin Phenon 4. In properties other than sugar oxidation, Phenon 4i resembled Phenon 3, and Phenons 4ii and 4iii resembled Phenon 2, but not so closely.

The minimum inhibitory concentration of penicillin was estimated for selected strains of Phenons 2, 3 and 3, and varied from < 0.1 to > 100 i.u./ ml. Strains of Phenons 3 and 4i were very sensitive, those of Phenons 2 and 4iii were resistant, and those of 4ii were intermediate or resistant.Ungrouped strains of Phenon 4 varied from very sensitive to resistant.

It was concluded, on the basis of these results and the data of Mandel & Thornley (1967) on DNA composition, that the non-motile coccoid rods in Phenons 2, 3 and 4 should be placed in a separate genus from other strains in the survey. Acinetobacter Brisou & Prévot is the most suitable generic name, and strains in Phenon 2 correspond to the type species, Acinerobacter anitratus. The relationships of Phenon 3 and the sub-divisions of Phenon 4 need further study, and it is not suggested that they should be given specific rank at present.

Phenons 2, 3 and 4 included strains formerly called and their classificition as The genus should be retained for strains resembling the motile, peritrichously flagellate type species, represented in this study in Phenon 5. It is suggested that the genus also should be reserved for any motile peritrichous strains which may prove suitable for inclusion. The few strains in this survey which had these properties were not very similar to each other, and the borderline between these strains and was not cfear. The strain ATCC I 5716, proposed as representative of the type species (Tulecke 1965) was unlike all other strains in the survey; ATCC 15716 fermented sugars and contained a large proportion of Gram-positive cells, and may be closer to a Gram-positive genus than to those studied here.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-49-2-211
1967-11-01
2019-10-22
Loading full text...

Full text loading...

http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-49-2-211
Loading
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error