Chemical and cultural characterization of CDC group WO-1, a weakly oxidative gram-negative group of organisms isolated from clinical sources.

Ninety-six strains of weakly oxidative gram-negative rods isolated primarily from clinical specimens form a distinct group that has been designated Centers for Disease Control (CDC) group WO-1 (WO stands for weak oxidizer). The phenotypic characteristics of CDC group WO-1 were most similar to those of Comamonas acidovorans, Pseudomonas mallei, and CDC pink coccoid group III. The WO-1 group can be differentiated from C. acidovorans by the oxidation of glucose (often weak and sometimes delayed), motility by means of one or two polar flagella, and, when positive, the complete reduction of nitrate and nitrite. Motility and usually the failure to produce arginine dihydrolase distinguish this group from P. mallei. The WO-1 strains differ from the pink coccoid group III by the absence of pink growth pigment, the lack of predominantly coccoid cellular morphology, and usually the inability to produce acid from xylose. The cellular fatty acid compositions of 29 group WO-1 strains were characterized by large amounts of C16:0 and C16:1w7c; smaller amounts of C18:1w7c, C14:0, C12:0, and 3-OH-C10:0; and trace to small amounts of C15:1w6 and C17:0 acids. The fatty acid profile of WO-1, compared with the profiles of other bacteria we have tested previously, was most similar to the profiles of two phenotypically different organisms, Comamonas terrigena (a nonoxidative, multipolar gram-negative rod) and Chromobacterium violaceum (a fermentative gram-negative rod). Ubiquinone-8 was the major quinone in the five WO-1 strains examined. Eighty-five percent of the WO-1 strains were isolated from human specimens. Thirty-three percent were from blood, and 10% were from cerebrospinal fluid.

Cellular fatty acid compositions of an unidentified organism and a bacterium associated with cat scratch disease.

The cellular fatty acid composition of a gram-negative bacterium associated with cat scratch disease was determined by capillary gas chromatography-mass spectrometry (GC-MS). The fatty acid profile of this organism was distinct from those of other bacteria we have tested and was characterized by an unknown acid which was identified as 11-methyloctadec-12-enoic acid. The position of the branched methyl group in this acid was established by GC-MS of the reduced acid, and the location of the double bond was confirmed by GC-MS analysis of dimethyl disulfide derivatives. Another clinical isolate with no known relationship to cat scratch disease but with similar morphological and biochemical features had a similar fatty acid profile, including 11-methyloctadec-12-enoic acid.

Biochemical and chemical characterization of pink-pigmented oxidative bacteria.

The biochemical and chemical characteristics were determined for 156 clinical isolates of pink-pigmented bacteria that are similar to but distinct from Methylobacterium extorquens (synonymous with Pseudomonas mesophilica). These isolates were gram-negative, nonfermentative, usually nonvacuolated, coccoid rods; all grew at 35 degrees C and were catalase and urease positive; the majority grew on MacConkey agar and were variable for oxidase production and motility. On the basis of oxidation of xylose and mannitol and hydrolysis of esculin, these 156 strains were subdivided into four groups that were designated "pink coccoid" groups I, II, III, and IV. Groups I, II, and III are similar to an unnamed taxon described by Gilardi and Faur in 1984; only strains of group IV hydrolyze esculin. The cellular fatty acid compositions of strains of groups I, II, and III were essentially identical and differed from strains of group IV by the absence of 3-OH-C14:0 and the presence of C19:0 delta and 2-OH-C19:0 delta. The fatty acid composition of group IV strains was most similar to that of M. extorquens but differed by the presence of small amounts of two C17:1 acids, 3-OH-C16:0, and 2-OH-C18:1.

Phenotypic characterization, cellular fatty acid composition, and DNA relatedness of aerococci and comparison to related genera.

Aerococci can be misidentified as streptococci, enterococci, pediococci, lactococci, or leuconostocs. To distinguish the genus and determine if another species is needed in the present taxon, we analyzed 37 aerococci for cellular fatty acids and compared them with 377 strains of gram-positive cocci, including the species type strains from each of the related genera. The cellular fatty acid profile of aerococci was distinguishable from other genera. Two relatively novel fatty acids found in the aerococci were identified as C16:1 omega 9c and C16:1 omega 9t. Eleven strains of aerococci (including a strain originally identified as "Gaffkya" species) were chosen for DNA-DNA reassociation studies with the type strain Aerococcus viridans ATCC 11563; DNAs from eight of these strains were more than 75% related to the type strain and had 1 to 4% divergence in related sequences. The remaining three strains were 60 to 70% related to the type strain, had 7 to 11.5% divergence, and may represent a second species, Aerococcus genospecies 2. beta-Glucuronidase, alpha-galactosidase, and beta-galactosidase were useful in characterizing the aerococci.

Characterization of CDC group DF-3 by cellular fatty acid analysis.

Fourteen strains of Centers for Disease Control group DF-3 bacteria were examined for cellular fatty acid composition to evaluate their chemical relatedness to known bacterial species and groups. The fatty acids were liberated from whole cells by base hydrolysis, methylated, and analyzed by capillary gas-liquid chromatography. All group DF-3 strains possessed a distinct fatty acid profile which was characterized by large amounts (24%) of 12-methyltetradecanoate (a-C15:0), moderate amounts of saturated iso-branched-chain acids (i-C14:0 and i-C15:0), and small to moderate amounts of both branched- and straight-chain hydroxy acids (3-OH C15:0, i-3-OH C16:0, 3-OH C16:0, and i-3-OH C17:0). This fatty acid profile was unique as compared with the profiles of other bacteria we have previously tested but was most similar to the profiles of Capnocytophaga species.

Cellular fatty acid composition of Kingella species, Cardiobacterium hominis, and Eikenella corrodens.

We determined the cellular fatty acid composition of reference strains and clinical isolates of each of the three Kingella species, Cardiobacterium hominis, and Eikenella corrodens by using capillary gas chromatography. Kingella denitrificans and Kingella kingae contained myristic (14:0) and palmitic (16:0) acids as major acids, whereas cis-vaccenic (18:1 omega 7c) and palmitic acids were the major acids in Kingella indologenes, C. hominis, and E. corrodens. C. hominis differed from the other four species by the absence of 3-hydroxylauric (3-OH-12:0) acid, from K. indologenes by the presence of 3-hydroxypalmitic (3-OH-16:0) acid, and from E. corrodens by the presence of 3-hydroxymyristic (3-OH-14:0) acid. E. corrodens contained a small amount (2%) of myristic acid, while the other four species contained moderate to large amounts (11 to 31%) of this acid.

Cultural and chemical characterization of CDC groups EO-2, M-5, and M-6, Moraxella (Moraxella) species, Oligella urethralis, Acinetobacter species, and Psychrobacter immobilis.

We determined phenotypic characteristics, cellular fatty acid composition, and isoprenoid quinone content of representative strains of CDC groups EO-2, M-5, and M-6, Moraxella (Moraxella) species, Oligella urethralis, Acinetobacter species, and Psychrobacter immobilis. All organisms contained ubiquinone with eight isoprene units as the major isoprenolog, but distinct differences were observed in fatty acid composition. Twenty-eight of the original collection of CDC group EO-2 strains were further identified as P. immobilis, EO-2, or EO-3 by distinctive cellular fatty acid profiles, cellular morphology, and pigment production. The cellular fatty acid compositions of M-5 and M-6 were similar but were clearly different from those of other organisms. The genus Acinetobacter was differentiated from other organisms in the study by small amounts of 2-hydroxydodecanoic acid (2-OH-12:0), and P. immobilis was differentiated by small amounts of decanoic acid (10:0) and a branched-chain 17-carbon acid (i-17:0). All Moraxella species were distinguished by small amounts of decanoic acid (10:0) and the absence of i-17:0. M. bovis, M. nonliquefaciens, and some strains of M. lacunata formed a single fatty acid group, while M. osloensis, M. phenylpyruvica, M. atlantae, and other strains of M. lacunata (M. lacunata II) had species-specific fatty acid profiles. O. urethralis differed from Moraxella species by the presence of large amounts (49%) of cis-vaccenic acid (18:1 omega 7c), small amounts (1%) of 3-hydroxyhexadecanoate (3-OH-16:0), and the absence of 10:0 and 3-hydroxydodecanoate (3-OH-12:0). The combined use of chemical data and a small number of conventional tests permitted rapid identification and differentiation of these organisms from each other and from related organisms.

Determination of hippurate hydrolysis by gas-liquid chromatography.

A rapid gas-liquid chromatographic procedure was developed to determine hippurate hydrolysis by microorganisms. Bacterial cells were inoculated into 0.4 ml of 1% sodium hippurate and incubated for 2 h at 37 degrees C. Cells were removed by centrifugation, and the benzoate released by enzyme activity was converted to methyl benzoate and analyzed by gas-liquid chromatography. This procedure is sensitive, and its specificity provides a high degree of reliability for organisms with weak hippuricase activity.