Coryneform bacteria are aerobically growing, asporogenous, non-partially-acid-fast, gram-positive rods of irregular morphology. Within the last few years, there has been a massive increase in the number of publications related to all aspects of their clinical microbiology. Clinical microbiologists are often confronted with making identifications within this heterogeneous group as well as with considerations of the clinical significance of such isolates. This review provides comprehensive information on the identification of coryneform bacteria and outlines recent changes in taxonomy. The following genera are covered: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter. Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, "Corynebacterium aquaticum," Arcanobacterium, and Actinomyces. Case reports claiming disease associations of coryneform bacteria are critically reviewed. Minimal microbiological requirements for publications on disease associations of coryneform bacteria are proposed.

The present study describes a database on the natural susceptibility of Listeria spp. to a wide range of antibiotics, which can be used to validate susceptibility testing results of these microorganisms.

Modern taxonomy has delineated Streptococcus gallolyticus subsp. gallolyticus, S. gallolyticus subsp. pasteurianus, Streptococcus infantarius subsp. coli, and S. infantarius subsp. infantarius within the heterogenous group of previously designated clinical Streptococcus bovis bacteria. In the present study, 58 consecutive blood culture isolates initially designated S. bovis were further characterized by applying phenotypic and molecular genetic methods, and possible disease associations were investigated by studying the patients' records. Published phenotypic characteristics of S. gallolyticus and S. infantarius were not unequivocal and did not allow an unambiguous phenotypic differentiation of the 58 clinical isolates. However, full-length 16S rRNA gene sequences clearly assigned the strains to S. gallolyticus subsp. gallolyticus (n ‫؍‬ 29), S. gallolyticus subsp. pasteurianus (n ‫؍‬ 12), and S. infantarius subsp. coli (n ‫؍‬ 17). Only 28% of the patients with available records presented with endocarditis and 7% presented with colon carcinoma, whereas 37% of the patients had altered liver parenchyma and 28% had gall bladder disease as underlying diseases. Detailed antimicrobial susceptibility data on both S. gallolyticus subspecies and S. infantarius subsp. coli are given for the first time. As a result of the extensive characterization of the largest number of S. gallolyticus and S. infantarius human clinical isolates published so far, emended species descriptions are given. It is recommended that both clinical microbiologists and infectious disease specialists avoid the designation S. bovis for true S. gallolyticus and S. infantarius strains in the future in order to get a clearer picture of the possible disease associations of these species.

The VITEK 2 card for gram-negative bacteria (bioMérieux, Marcy-lEtoile, France) has been redesigned to improve the identification of fermenting and nonfermenting bacilli. Forty-seven biochemical tests, including 19 enzymatic tests, are present in the new card and interpreted in a kinetic mode. Final identification results are available within 10 h. The database allows the identification of 159 different taxa. Six hundred fifty-five gram-negative rods (GNR; 511 fermenters and 144 nonfermenters), representing 54 taxa, were tested. Strains were taken from fresh routine primary isolation plates (n ‫؍‬ 157), from stored routine plates (n ‫؍‬ 301), and from stock cultures (n ‫؍‬ 197). Six hundred thirty-seven strains (97.3%) were correctly identified to the species level, 14 strains (2.1%) gave low discrimination results requiring additional tests, and 4 strains (0.6%) gave discordant results; not a single strain remained unidentified. Nearly 92% of all isolates were correctly identified within 7 h of incubation. The robustness of the system was demonstrated by the fact that strains were grown on four different agar media before testing. The system may also have the potential to be applied directly to primary isolation plates, since in this instance 96.2% of 157 GNR were correctly identified and 3.8% gave low discrimination results. The new VITEK 2 card for gram-negative bacteria seems to be a promising new tool for routine, rapid identification of GNR.Highly automated identification systems have been introduced in many medium-to high-throughput clinical microbiology laboratories worldwide within the last 15 years. These systems, such as VITEK (bioMérieux, Marcy l'Etoile, France), MicroScan (Dade, West Sacramento, Calif.), and PHOENIX (BD, Sparks, Md.), have contributed to better and more-costeffective management of patients by enabling clinical microbiologists to identify medically relevant bacteria more rapidly and accurately. In a previous article, it was emphasized that an important value for a highly standardized commercial identification system must be the capability of the manufacturer to maintain or even improve the performance of an identification system over time (2). The new VITEK 2 card (NGNC; bioMérieux) for identification of gram-negative rods (GNR) was recently created during the evolutionary process of research on and further development of the VITEK 2 instrument. The rationale for designing the NGNC was to broaden the database and to improve identification results. The NGNC contains 47 tests (26 that had been included in the previous card and 21 new tests), compared to 41 in the established VITEK 2 ID-GNB card (GNC), and 159 taxa are covered by the new database corresponding to the NGNC, compared to only 101 for the GNC database. While the GNC tests are based on fluorescence technology, the NGNC tests are based on colorimetric detection. Measurements are required every 15 min for both the GNC and NGNC tests, and the total incubation times are up to approximately 10 h for the NGNC and 3 h for the GNC. ...

Ten strains of a hitherto undescribed catalase-negative, facultatively anaerobic, coryneform bacterium were isolated or collected by workers at three European clinical bacteriology laboratories or reference centers. These strains were isolated from humans, and most came from abscess material. Biochemical and chemotaxonomic characterization revealed that the strains belonged to the genus Actinomyces. The phenotypic features of the 10 strains were incompatible with the descriptions of the previously established Actinomyces species. A comparative 16s rRNA gene sequence analysis demonstrated that the previously undescribed strains constitute a new line in the genus Actinomyces. The name Actinomyces europaeus sp. nov. is proposed for these clinical isolates. The type strain is CCUG 32789A.In the 1 9 9 0~~ there has been increasing recognition of the importance of coryneform bacteria (i.e., aerobic, asporogenous, irregular, non-partially acid-fast, gram-positive rods) as opportunistic human pathogens (8). As a result of increased medical interest in such organisms, combined with intensified taxonomic investigations, a number of new coryneform and related high-G+ C-content bacteria have been described in recent years (8). The recognition of new coryneform pathogens in laboratories is complicated by the absence of reliable commercial identification systems with in-depth databases and the heterogeneity of the organisms encountered. Recent studies have shown, however, that the use of phenotypic approaches (biochemical profiles, lipids, cell walls) and molecular taxonomic approaches (e.g., 16s rRNA sequencing) in concert (polyphasic taxonomy) provides not only a powerful means for recognizing and delineating such organisms, but also the foundation for developing improved identification schemes. In this article we report the use of a polyphasic approach to characterize a group of 10 catalase-negative, facultatively anaerobic, coryneform bacterial strains obtained from human clinical specimens, which could not be assigned to any previously established taxon. Based on the results of the present study, a new species, Actinomyces europaeus, is proposed. MATERIALS AND METHODSBacterial strains. The origins of the strains studied and their clinical sources are given in Table 1. Four strains were isolated by workers at the Department of Medical Microbiology, University of Zurich, Zurich, Switzerland, and three strains were isolated by workers at the Stichting Streeklaboratorium, Goes, The Netherlands, by standard methods (5). The three remaining isolates were referred to the Culture Collection of the University of Goteborg, Goteborg, Sweden.Morphological and biochemical characteristics. The strains were grown aerobically at 37°C in a 5% C0,-enriched atmosphere on Columbia agar (Difco Laboratories, Detroit, Mich.) supplemented with 5% sheep blood. The same