Six species and six additional genovars are combined within the so-called Enterobacter cloacae complex, with one of them being the species Enterobacter hormaechei. In a recent population genetic study, two genetic clusters were found in close phylogenetic proximity to the genetic cluster of E. hormaechei. In order to prove the hypothesis that these three genetic clusters belong to the same species, we performed cross-hybridization experiments in microplates with DNAs of representatives of each genetic cluster. The close phylogenetic relationship among the clusters was reflected by their relatively low ⌬T m values, ranging from 0.3 to 4.8, confirming the hypothesis that the clusters are parts of the same species. These clusters can be distinguished from the other species of the E. cloacae complex, which have ⌬T m values of 5.6 to 10.3. Forty-eight E. hormaechei strains from the different genetic clusters were phenotypically characterized with 129 biochemical tests. In this way, E. hormaechei could be differentiated from the other species of the E. cloacae complex because it tests negative in the 3-hydroxy-butyrate test. The three genetic clusters of E. hormaechei could also be differentiated from each other by using phenotypic tests. Hence, we propose three new subspecies of E. hormaechei corresponding to genetic clusters VI, VII, and VIII of the E. cloacae complex. E. hormaechei subsp. hormaechei comb. The genus Enterobacter was first described by Hormaeche and Edwards (9). Since the transfer of Enterobacter agglomerans to the genus Pantoea (5), 14 species are included in the genus (1), including Enterobacter aerogenes, which is considered a homotypic synonym of Klebsiella mobilis because it has the same type strain (13). Around Enterobacter cloacae, six genetically related and phenotypically similar species have been combined within the so-called E. cloacae complex (7), i.e., E. cloacae, Enterobacter asburiae, Enterobacter dissolvens, Enterobacter hormaechei, Enterobacter kobei, and Enterobacter nimipressuralis. In addition to these species, at least six genetic clusters are phylogenetically delineated within the complex (7).Two of the most prominent clusters (clusters VI and VIII) are closely related to the species E. hormaechei, together forming the so-called E. hormaechei metacluster. They displayed 98 to 99% sequence identity in an analysis of three housekeeping genes and showed nearly identical restriction patterns of their ampC genes, which chromosomally code for a Bush class 1 beta-lactamase (7).E. hormaechei was first described on the basis of 23 isolates sent to the Centers for Disease Control and Prevention (Atlanta, Ga.) for identification. At that time, they could not be assigned to a species, since they were negative in D-sorbitol and melibiose tests and did not fit the biochemical profile of any established Enterobacter species. Later, this preselected set of isolates turned out to be genetically closely related to each other. The species E. hormaechei was proposed to be lactose, D-sorbitol, raffi...

The phenotypes of 153 strains belonging or related to the genus Bijidobacterium were studied. These organisms included 38 collection strains and 115 wild strains (41 strains of human origin, 56 strains of animal origin, and 18 strains obtained from rivers or sewage). Our phenotypic analysis revealed seven main groups that were subdivided into 20 subgroups. Seven subgroups contained no type or collection strain. Among the human strains, the type strains of BiJidobacterium pseudocatenulatum and B . catenulatum fell into group I, which contained the type strains of B. adolescentis (subgroup Ib), B . dentium (subgroup Ic), and B. angulatum (ungrouped). The type strain of B. breve belonged to subgroup IIIal, and the type strains of B . infantis and B . longum fell into subgroup IIIbl. Group VII comprised only wild strains that were isolated from human infant feces. Among the animal strains, group I1 consisted mainly of bifidobacteria that were isolated from pig feces and contained the type strains of B . suis (subgroup IIb), B . thermophilum (subgroup IIf), B . choerinum, and B. boum (ungrouped). Wild strains belonging to group V were isolated from pig, calf, cow, and chicken feces; this included the type strains of B . animalis (subgroup Va), B . magnum (subgroup Vb), B . pseudolongum, and B . globosum (subgroup Vc). The strains of human origin (groups I, 111, and VII) were well separated from the animal strains (groups 11, IV, and V). It was not surprising that the wild strains isolated from surface water or sewage were distributed in the animal groups as well as the human groups. Thus, bifidobacteria can be considered to be successful indicators of human or animal fecal pollution when they are correctly classified. The acidification patterns were not adequate to differentiate Bijidobacterium species, as determined previously by Mitsuoka

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A study was performed to evaluate a new manual miniaturized system, API Coryne (API-bioMerieux, Inc., La Balme les Grottes, France), in which conventional biochemical methods were used to identify 240 isolates of coryneform and related bacteria. A total of 40% of the isolates were excluded from the study because they could not be identified by conventional methods. Identifications of the 240 isolates obtained with API Coryne showed a 97.6% concordance with conventional methods (79% after 24 h of incubation, 21% after 48 h of incubation): 158 (65.8%) isolates were identified with no further testing, and extra testing was required for 76 (31.8%) isolates. In three (1.2%) cases, the organisms did not correspond to any key in the code book and could not be identified by the computer service of the manufacturer. Only three (1.2%) strains were misidentified. The system was shown to be reliable and rapid when compared with standard identification methods.