Identification of Achromobacter species by cellular fatty acids and by production of keto acids.

The cellular fatty acid composition and metabolic products of 12 reference strains of Achromobacter sp. and A. xylosoxidans were determined by gas-liquid chromatography (GLC). Results showed that the two Achromobacter groups are strikingly different and can be readily distinguished on the basis of cellular fatty acids and the short-chain acids produced by Achromobacter sp. The major cellular fatty acids of Achromobacter sp. were octadecenoic (18:1) and a 19-carbon cyclopropanoic (19:0 delta) acid, whereas hexadecanoic (16:0) and a 17-carbon cyclopropanoic (17:0 delta) acid were principal components of the lipids of A. xylosoxidans. Hydroxy acids were not found in strains of Achromobacter sp. but comprised approximately 20% of the cellular fatty acids of A. xylosoxidans. In addition, Achromobacter sp. produced relatively large amounts of 2-ketoisocaproic acid, which was detected in only trace amounts from strains of A. xylosoxidans. The data show that GLC tests provide additional criteria for differentiating groups which are very closely related when evaluated with conventional tests. The GLC tests can be readily adapted in the clinical laboratory because they are rapid, highly reproducible, relatively inexpensive, and simple to perform.

Cellular fatty acids and metabolic products of Pseudomonas species obtained from clinical specimens.

The cellular fatty acid composition of 112 reference strains and clinical isolates of Pseudomonas species was determined by gas-liquid chromatography (GLC). The presence and relative amounts of cyclopropane, hydroxy, and branched-chain fatty acids were distinguishing features of these strains. Determination of short-chain fatty acids extracted from spent growth media provided an additional means for identifying some strains. Our results show that clinical isolates of pseudomonads can be divided into eight distinct GLC groups. The procedures were especially useful for distinguishing glucose-nonoxidizing pseudomonads, which are difficult to identify by conventional criteria. Since the GLC procedures are simple, rapid, and highly reproducible, they are useful in diagnostic laboratories that process large numbers of cultures. Coupled with selected conventional tests, the analysis of short-chain and cellular fatty acids can be very useful for rapid screening of clinical isolates of Pseudomonas species.

Cellular fatty acids of Alcaligenes and Pseudomonas species isolated from clinical specimens.

The cellular fatty acid composition of 25 clinical isolates of Alcaligenes and Pseudomonas was determined by gas-liquid chromatography (GLC). The GLC fatty acid profiles of three species of Pseudomonas were markedly different from those of Alcaligenes. The most significant differences were the presence and relative amounts of hydroxy, branched-chain, and cyclopropane fatty acids. One of the major fatty acids in A. faecalis was a 17-carbon cyclopropane (17 delta) acid, whereas a 15-carbon branched-chain acid (13-methyl tetradecanoate) characterized isolates of P. putrefaciens. The determination of these fatty acids by GLC provides a rapid and specific means of distinguishing clinical isolates of Pseudomonas and Alcaligenes.

Identification of microorganisms by gas chromatographic-mass spectrometric analysis of cellular fatty acids.

The cellular fatty acid compositions of strains of Pseudomonas aeruginosa, P. cepacia, and P. maltophilia were determined by gas-liquid chromatography. A variety of acids was detected in these organisms, including branched and straight-chain acids, cyclopropane, and hydroxy acids. Comparison of the presence and relative amounts of these acids was useful in distinguishing the three species. Three branched-chain hydroxy acids not found in other bacteria were present in P. maltophilia and were identified by gas chromatography, mass spectrometry, and infrared spectroscopy.

Cellular fatty acid composition of WIGA, a rickettsia-like agent similar to the Legionnaires disease bacterium.

The cellular fatty acid composition of OLDA, a rickettsia-like agent isolated in 1947, was essentially identical to that of the Legionnaires disease bacterium (LDB). WIGA, another rickettsia-like agent isolated in 1959, contained the same fatty acids as OLDA and other LDB but differed significantly from these strains in relative amounts of the major acids present. The major acid of OLDA and other LDB was i-16:0 whereas a-15:0 was the major acid of WIGA.

Further studies of the cellular fatty acid composition of Legionnaires disease bacteria.

The cellular fatty acid composition of 36 strains of the Legionnaires disease bacterium was determined by gas chromatography after growth on different media. The fatty acid profile of each strain was essentially identical on each medium and was characterized by large amounts (greater than 68%) of branched-chain acids.

Cellular fatty acids of Flavobacterium meningosepticum and Flavobacterium species group IIb.

The cellular fatty acid profiles of Flavobacterium meningosepticum and Flavobacterium species group IIb were markedly different from those of related bacteria. The profiles were characterized by the presence of 13-methyl-tetradecanoate and three uncommon acids: 2-hydroxy-13-methyl-tetradecanoate, 15-methyl-hexadecanoate, and 3-hydroxy-15-methyl-hexadecanoate.

Gas-liquid chromatography of bacterial fatty acids with a fused-silica capillary column.

The use of flexible, fused-silica capillary column for gas-liquid chromatographic analysis of bacterial fatty acids is illustrated with Propionibacterium acnes, Propionibacterium shermanii, and a standard methyl ester mixture.

Cellular fatty acid composition of Legionella longbeachae sp. nov.

The cellular fatty acid composition of Legionella longbeachae was determined by gas-liquid chromatography. As in other Legionella species, the fatty acids of this new species are characterized by relatively large amounts of branched-chain acids.

Chemical characterization of Flavobacterium odoratum, Flavobacterium breve, and Flavobacterium-like groups IIe, IIh, and IIf.

The cellular fatty acid, sphingolipid, and isoprenoid quinone compositions of Flavobacterium odoratum, Flavobacterium breve, and Flavobacterium-like groups IIe, IIh, and IIf were determined, using thin-layer, gas-liquid, and reverse-phase high-performance liquid chromatography. The fatty acid data showed that groups IIe, IIh, and IIf were similar to recognized Flavobacterium species by the presence of relatively large amounts of iso-branched hydroxy and nonhydroxy acids. Groups IIe and IIh were essentially identical in fatty acid composition but were distinguished from group IIf, F. breve, and F. odoratum on the basis of minor qualitative and quantitative differences. All strains tested contained menaquinone 6 as the major isoprenoid quinone, and all lacked sphingolipids. Overall, the chemical data suggest that groups IIe, IIh, and IIf are additional Flavobacterium species and are different from sphingobacteria, which contain sphingolipid and menaquinone 7 as the major quinone.

Cellular fatty acid composition of isolates from Legionnaires disease.

The cellular fatty acids of four isolates from Legionnaires disease and two antigenically related isolates were identified by gas chromatography, mass spectrometry, and associated techniques. The six isolates had essentially the same fatty acid composition, which was characterized by large amounts (greater than 80%) of branched-chain acids.

Cellular fatty acid composition of Pseudomonas marginata and closely associated bacteria.

The cellular fatty acid compositions of the lectotype strain and four clinical isolates of Pseudomonas marginata were determined by gas-liquid chromatography and compared with 11 strains of the Centers for Disease Control Pseudomonas-like group 2, which are similar to P. marginata in a number of conventional biochemical tests. Isolates of P. marginata were readily distinguished from Pseudomonas-like group 2 by the presence of a C17:0 cyclopropane acid and hydroxy acids 3-OH-C14:0, 2-OH-C16:0, 3-OH-C16:0, and 2-OH-C18:1, whereas strains of Pseudomonas-like group 2 contained C16:1 delta 9 as a major acid with small amounts of 3-OH-C12:0 and 2-OH-C14:0 acids. Our data show that cellular fatty acid composition provides useful additional information that can be combined with selected conventional tests to provide a more reliable and rapid identification of P. marginata and related bacteria.

Cellular fatty acids of Capnocytophaga species.

The cellular fatty acid composition of 18 clinical isolates and 4 reference strains of Capnocytophaga species (Capnocytophaga ochracea, Capnocytophaga gingivalis, and Capnocytophaga sputigena) was determined by gas-liquid chromatography. The fatty acid profiles of the 22 cultures were essentially identical and were characterized by major amounts (60% or greater) of a saturated, iso-branched-chain, 15-carbon acid (13-methyl-tetradecanoate) and the presence of two relatively uncommon saturated, iso-branched, 3-hydroxy acids (13-methyl-3-hydroxy-tetradecanoate and 15-methyl-3-hydroxy-hexadecanoate). The presence and relative amounts of these acids distinguish Capnocytophaga spp. from other gliding bacteria.

Cellular fatty acid composition of organisms frequently associated with human infections resulting from dog bites: Pasteurella multocida and groups of EF-4, IIj, M-5, and DF-2.

The cellular fatty acid composition of Pasteurella multocida and four unclassified groups of gram-negative bacteria (EF-4, M-5, IIj, and DF-2) which are frequently associated with human dog-bite infections was determined by gas-liquid chromatography. Strains of P. multocida were readily distinguished from the unclassified groups by the presence of 3-hydroxy myristic acid (3-OH- 14:0). Groups M-5 and EF-4 were characterized by the presence of 3-hydroxy lauric (3-OH-12:0) acid. Only group EF-4 organisms contained 2-OH-16:0, a-17:0, and 17:0 cyclopropane acids. Groups IIj and DF-2 differed from the other groups by the presence of large amounts of a branched-chain 15-carbon acid (i-15:0); they differed from each other by the presence of i-2-OH-15:0 and i-17:1 acids in IIj, which were absent in DF-2. The data indicate that gas-liquid chromatographic analysis for cellular fatty acids provides an additional test for rapid differentiation of these gram-negative organisms associated with dog-bite infections. Similarities observed in the fatty acid compositions of Flavobacterium, IIj, and DF-2 suggest that these two unclassified groups may be additional species of Flavobacterium.

Cellular fatty acid composition of Pseudomonas paucimobilis and groups IIk-2, Ve-1, and Ve-2.

The cellular fatty acid composition of Pseudomonas paucimobilis (IIk-1) and group IIk-2, Ve-1, and Ve-2 was determined by gas-liquid chromatography. The unnamed groups were readily distinguished from P. paucimobilis by cellular fatty acids. The data strongly suggest that these bacteria may be additional species of Pseudomonas and Flavobacterium.

Cellular fatty acids of Brucella canis and Brucella suis.

The cellular fatty acid composition of Brucella canis and Brucella suis was determined by gas-liquid chromatography. The presence of relatively large amounts of a 19-carbon cyclopropane fatty acid in B. suis was a major distinguishing feature between these organisms. The gas-liquid chromatography test for cellular fatty acids provides an additional criterion for the distinction of antigenically rough strains of B. suis which cannot be differentiated from B. canis by conventional procedures.

Characteristics of environmental isolates of Legionella pneumophila.

Thirty-eight cultures of Legionella pneumophila isolated from surface waters were characterized by their morphological, tinctorial, biochemical, and serological properties and by their ability to produce disease in guinea pigs. Their susceptibility to antimicrobial agents also was tested. When they were compared with clinical isolates, no important differences were found between cultures from the two sources. Sodium hippurate hydrolysis, gelatin liquefaction, pigment formation, and beta-lactamase and alkaline phosphatase activity were useful in differentiating the four described species of Legionella. Hydrolysis of diacetylfluorescein and the inability to reduce nitrate help to distinguish Legionella species from other gram-negative bacterial rods.

Thermophilic bacteria: a new cause of human disease.

We studied a group of 31 bacterial isolates from clinical specimens, received by the Centers for Disease Control since 1961, which have been denoted thermophilic for their unusual ability to grow at 50 degrees C. Microbiological characteristics were determined for the group, and an assessment of their clinical significance was made based on retrospective chart review. These bacteria are all gram-negative, nonfermentative, nonsporulating rods, most of which grow better at 42 or 50 degrees C than at 35 degrees C. Some of the bacteria could be implicated as the etiological agents for meningitis, endocarditis, and septicemia. Thermophilic bacteria should be considered potential pathogens when isolated from appropriate clinical specimens.