The cellular fatty acid compositions of 368 strains of Campylobacter species or Campylobacter-like organisms were determined by gas-liquid chromatography. Most of the strains (339) were placed in one of three groups based on differences in fatty acid profiles. Group A contained Campylobacter jejuni (97%) and most C. coli (83%) strains and was characterized by the presence of a 19-carbon cyclopropane fatty acid (19:0 cyc) and 3-hydroxytetradecanoic acid (3-OH-14:0). Group B included all C. laridis and some C. coli (17%) strains; its profile was similar to that of group A, except that 19:0 cyc was absent. Group C contained C. fetus subsp. fetus and C. fetus subsp. venerealis and was characterized by the presence of 3-OH-14:0 and 3-hydroxyhexadecanoic acid (3-OH-16:0) and the absence of 19:0 cyc. Twenty-nine isolates were placed in four additional groups. Group D included the type strain of "C. cinaedi" and 14 other isolates, which were differentiated by the presence of dodecanoic acid (12:0), 3-hydroxydodecanoic acid (3-OH-12:0), and 3-OH-16:0 and the absence of hexadecenoic acid (16:1) and 3-OH-14:0. Group E contained the type strain of "C. fennelliae" and two additional isolates, which were differentiated by the presence of a 16-carbon aldehyde and a 16-carbon dimethylacetyl and the absence of 16:1. Group F included the type strain and one reference strain of C. cryaerophila and six human isolates whose phenotypic characteristics were similar to those of this species; this group was distinguished by the presence of two isomers of 16:1, tetradecenoic acid (14:1), and 3-OH-14:0. Group G included three strains of C. pyloridis and was characterized by the presence of 19:0 cyc, 3-OH-16:0, and 3-hydroxyoctadecanoic acid (3-OH-18:0) and by the absence of 16:1 and 3-OH-14:0.

A standard mixture of 25 short-chain fatty acids was resolved by highperformance liquid chromatography, using an Aminex HPX-87 column. The acids produced in culture media by anaerobic bacteria were analyzed by high-performance liquid chromatography after extraction with ether and reextraction into a small volume of 0.1 N NaOH. The presence of fumaric acid in culture extracts of Peptostreptococcus anaerobius was confirmed by gas chromatography-mass spectrometry analysis of the trapped eluent fractions from the high-performance liquid chromatography column.

The cellular fatty acid compositions of 10 Vibrio species, two Aeromonas species, three Photobacterium species, Plesiomonas shigelloides, and Escherichia coli were determined by using capillary gas-liquid chromatography (GLC). The major fatty acids in all Vibrionaceae species and E. coli were hexadecenoic, hexadecanoic, and octadecenoic acids. Qualitative and quantitative differences in hydroxy, branched, and cyclopropane fatty acids and in isomers of unsaturated 16-and 18-carbon acids were used to divide the 29 strains belonging to 17 species tested into 13 GLC groups. Of the 13 groups, 10 contained one species, 2 contained two species, and 1 contained three species. All of the Vihrionaceae cultures were differentiated from E. coli (GLC group I) because the concentration of hexadecenoic acid was greater than the concentration of hexadecanoic acid; in E . coli, this ratio was reversed. Aeromonus hydrophila (GLC group 11) and Aeromonas salmonicida (GLC group 111) were differentiated from the Vibrio and Photobacterium species and from Plesiomonas shigelloides because the Aeromonus cultures did not contain 3-hydroxylauric acid. Seven of 10 Vibrio species, including Vibrio fluvialis (GLC group IV), Vibrio parahaemolyticus (GLC group V), Vibrio alginolyticus (GLC group V), Vibrio harveyi (GLC group V), Vibrio splendidus (GLC group VI), Vibrio vulniJicus (GLC group VII), and Vibrio cholerae (GLC group VIII), contained both cis-9-hexadecenoic and cis-11-hexadecenoic acids. These seven species could be differentiated from Vibrio gazogenes (GLC group IX), Vibrio metschnikovii (GLC group XII), Vibrio anguillarum (GLC group XIII), Photobacterium leiognathi (GLC group XIII), Photobacterium phosphoreum (GLC group XI), Photobacterium angustum (GLC group XI), and Plesiomonas shigelloides (GLC group X) because these latter seven species did not contain cis-1 1-hexadecenoic acid. The only Vibrionaceae cultures which contained cyclopropane acids were Photobacterium phosphoreum, Photobacterium angustum, and one of the two strains of Plesiomonas shigelloides examined. Branched-chain acids were found in all species tested, and their concentrations ranged fmm less than 1 to 22%. Although the 16 Vihrionaceae species tested had many similarities in their cellular fatty acid compositions, there were differences which could be used for differentiation of members of this family at the genus and species levels.

Several biochemical test systems were studied for their potential usefulness for the examination of strains of Campylobacter species. Most (81%) of the C. jejuni strains hydrolyzed sodium hippurate, but strains of C. fetus, C. sputorum, and C. fecalis did not. Some (46%) of the C. jejuni strains and all of the C. sputorum subsp. sputorum, C. sputorum subsp. bubulus, and C. fecalis strains hydrolyzed DNA, but the C. fetus and C. sputorum subsp. mucosalis strains did not. Strains of all species of Campylobacter grew on charcoal-yeast extract agar, but 47% of the C. jejuni strains did not. Alkaline phosphatase activity was recorded for some strains of C. jejuni, but all other species were negative for this activity. Aryl sulfatase activity was detected in 7% of the C. jejuni, 15% of the C. fetus subsp. fetus, and all of the C. sputorum subsp. sputorum, C. sputorum subsp. bubulus, and C. fecalis strains, but it was not detected in the C. fetus subsp. venerealis and C. sputorum subsp. mucosalis strains. Most (93%) of the C. jejuni but none of the other Campylobacter strains contained lactobacillic acid when examined for cellular fatty acids. On the basis of results from three of these tests (hippurate hydrolysis, DNA hydrolysis, and growth on charcoal-yeast extract agar), clinical strains of C. jejuni were placed in eight biotypes.

Catalase-negative or weakly positive (CNW) thermotolerant campylobacteria, first isolated from dogs in 1983, were recently recognized as a new species, "Campylobacter upsaliensis," but their association with human illness has not been established. Twelve human isolates received at the Centers for Disease Control between 1980 and 1986 were identified as CNW campylobacteria by biochemical tests, cellular fatty acid composition, and antimicrobial susceptibility patterns. Eleven CNW Campylobacter strains tested by DNA-DNA hybridization (hydroxyapatite method) were all highly related and were related to two "C. upsaliensis" strains at the species level (86% under optimal conditions and 76% under stringent conditions). Clinical information was obtained for Il human isolates from three stool and eight blood specimens. They were isolated from four female and seven male patients 6.5 months to 83 years of age residing in 10 different states. The patients had a wide spectrum of illnesses. The stool isolates were obtained from two previously healthy persons during episodes of acute gastroenteritis and from one immunocompromised patient with persistent diarrhea and fever. The blood isolates were obtained from two infants with fever and respiratory symptoms; a young woman with a ruptured ectopic pregnancy; three elderly men with underlying chronic diseases; and two immunocompromised adults. In a bactericidal assay to assess sensitivity to serum, seven of eight blood isolates showed some resistance to killing by pooled normal human serum. These observations suggest that "C. upsaliensis" is a potential human pathogen associated with both gastroenteritis and bacteremia in normal hosts and with opportunistic infection in immunocompromised individuals.