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Variations between and within individuals, and correlations between concentrations of bacterial metabolites, including putrefactive products, ammonia and short chain fatty acids (SCFAs), enzyme activities, moisture and pH, as well as bacterial composition, were studied in faecal samples from seven healthy adults over a period of 7 months. Large variations, both between and within individuals, were observed in concentrations of putrefactive products. Although values for ammonia, SCFAs, enzyme activities, moisture and pH were generally variable, significant person-to-person differences were observed. While ranges of log viable counts of the predominant bacteria such as eubacteria, bifidobacteria and bacteroides in each subject remained between 0.2 and 1.3, those of enterobacteria, streptococci (including enterococci) and lecithinase-negative clostridia varied between 0.4 and 3.0. Levels of bifidobacteria, enterobacteria, streptococci and total aerobic bacteria showed inter-individual variations. Correlations were found among certain of the parameters: moisture correlated negatively with p-cresol (r = -0.707), pH (r = -0.671) and beta-glucosidase activity (GS) (r = -0.608), and positively with acetic acid (r = 0.621), while negative correlations were observed in pH with acetic and butyric acids (r = -0.690 and -0.623, respectively). No significant correlations were found between bacterial compositions, and other faecal factors such as pH, moisture, metabolic enzyme activities and concentrations of putrefactive products.

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The genetic and phenotypic properties of 18 strains which were considered to be Bacteroides oralis or related organisms were examined. These strains were differentiated into several groups on the basis of deoxyribonucleic acid homology, physiological properties, guanine-plus-cytosine content of the deoxyribonucleic acid, and electrophoretic patterns of cell proteins. The groups were considered to constitute separate species. Strains of group I (strains VPI 7570A, WAL 3030, and 1221) belonged to the newly described species Bacteroides denticola. Strain VPI 8906D (group 11) has been designated a new species, Bacteroides bucculis, by Shah and Collins. Strain VPI D27B-24 (group 111) is the type strain of B. oralis. However, the biological properties of none of the three groups described above fit the original description of B. oralis (Loesche et al. 1964). Strain VPI D22A-7= did not belong to any of the three groups but had phenotypic properties that matched the phenotypic properties given in the first description of B. oralis. We propose the name Bacteroides veroralis for this organism and have deposited strain VPI D22A-7 in the American Type Culture Collection (= ATCC 33779) as the type strain.Bacteroides oralis was first described by Loesche et al. (16) as a gram-negative anaerobic bacillus from the oral cavity of humans. The biochemical characteristics of B. oralis reportedly are similar to those of Bacteroides melaninogenicus subsp. melaninogenicus and Bacteroides rurninicola (6, 16, 25), except that B. rnelaninogenicus produces a black pigment (7, 15) and B. ruminicola requires hemin for growth and ferments pentose (1). The type strain of B. oralis designated by Loesche et al. (16) apparently has been lost, and the strain now designated 7CM has been reclassified as Bacteroides vulgatus (23). A second strain deposited by Loesche et al. as representative of B. oralis (strain Loesche 8B [= ATCC 159301) was reclassified as B. melaninogenicus subsp. melaninogenicus (4) and is now the type strain of Bacteroides loescheii (8). B . oralis VPI D27B-24 (= ATCC 33269) has been designated the type strain of B. oralis.The present study was undertaken to clarify the relationships of strains which are similar to B . oralis ( 5 , 23, 27, 29); this was done by examining the physiological and biochemical characteristics, deoxyribonucleic acid (DNA) base compositions, DNA homologies, and protein electrophoretic mobility patterns of these strains. MATERIALS AND METHODSBacterial strains. We studied the following strains of B. oralis and similar organisms: VPI 7570A, from T.Hofstad; WAL 3030, from S. M. Finegold; 1221, from S. S. Socransky; WPH 179, from J. G. Collee; 5540 and 7880, from H. Werner; VPI 8906D, VPI D22A-7T,