Presumptive Identification of Group D Streptococci: the Bile-Esculin Test
01 Aug 1970-Applied and Environmental Microbiology (American Society for Microbiology)-Vol. 20, Iss: 2, pp 245-250
TL;DR: Evidence of the need for standardization of salt and heat-tolerance tests was obtained and data indicate that the bile-esculin test provided a reliable means of identifying group D strePTococci and differentiating them from non-group D streptococci.
Abstract: Six tests commonly used for the presumptive identification of group D streptococci were evaluated. Strains tested included 282 group D streptococci and 366 non-group D. Ratios of percentages of group D to non-group D strains which gave positive reactions for each test are as follows: bile-esculin, 100:2; salt tolerance, 88:24; heat tolerance, 100:80; SF broth, 86:1; KF broth, 99:40; and methylene blue milk reduction, 90:17. These data indicate that the bile-esculin test provided a reliable means of identifying group D streptococci and differentiating them from non-group D streptococci. Methodology for reading and interpreting positive reactions and time of incubation of the bile-esculin medium was defined. Evidence of the need for standardization of salt and heat-tolerance tests was obtained.
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TL;DR: A key for the differentiation of human isolates of viridans streptococci is proposed and is proposed based on stable enzymatic reactions rather than on results of tolerance tests.
Abstract: Twelve hundred and twenty-seven clinical isolates and eighty stock strains of viridans streptococci were tested for serological and physiological characteristics. Because the serological reactions of these strains varied, a differentiation scheme could not be based on these reactions. For the same reason, there could be no correlation of serological characteristics with physiological characteristics. Nearly 97% of the clinical isolates were speciated by differences in physiological characteristics. Ten different physiological species were recognized. The physiological speciation scheme was based on stable enzymatic reactions rather than on results of tolerance tests. The study included air-tolerant anaerobic streptococcal strains as well as viridans streptococcal strains not normally found in humans. The differentiation scheme and nomenclature of the author are related to those of other investigators. Differences in the distribution of species isolated from different clinical sources and human infections were also noted. A key for the differentiation of human isolates of viridans streptococci is proposed.
468 citations
TL;DR: Ninety-eight percent of the 262 strains of group D streptococci isolated from human sources were speciated by a spectrum of tests that allowed us to recognize atypical as well as typical strains within species.
Abstract: The speciation of 262 strains of group D streptococci isolated from human sources is described. One hundred forty-two isolates from blood cultures were included; 96 of these were submitted as isolates from clinical cases of subacute bacterial endocarditis. The results show that 98 Streptococcus faecalis, 29 S. faecalis var. zymogenes, 44 S. faecalis var. liquefaciens, 27 S. faecium, 13 S. durans, 44 S. bovis, and 7 unspeciated S. bovis-like group D isolates were identified. No S. faecium var. casseliflavus, S. equinus, or S. avium (group Q streptococci) were identified among the human isolates. The speciation procedures and techniques are detailed. The procedures and limitations of the tests used are discussed. Ninety-eight percent of the 262 strains were speciated by a spectrum of tests that allowed us to recognize atypical as well as typical strains within species.
335 citations
01 Jan 1995
TL;DR: The history of the enterococci cannot be considered separately from that of the genus Streptococcus, because of early links between these early links.
Abstract: The history of the enterococci starts in 1899 with the description by Thiercelin of a new Gram-positive diplococcus, which was later included in the new genus Enterococcus with the type species Enterococcus proteiformis (Thiercelin and Jouhaud, 1903). In 1906, however, Andrewes and Horder renamed Thiercelin’s ‘enterocoque’ as Streptococcus faecalis based on its ability to form short or long chains. Because of these early links, the history of the enterococci cannot be considered separately from that of the genus Streptococcus.
253 citations
TL;DR: A battery of five tests was used for presumptive identification of the pathogenic streptococci and more than 99% of the group A, 99 of thegroup B, 81 of the beta-hemolytic strePTococci non-group A, B, or D, and 94 of the viridans streptitisci were correctly identified.
Abstract: A battery of five tests was used for presumptive identification of the pathogenic streptococci. The non-serological methods included determination of hemolysis for all strains, bacitracin susceptibility for group A streptococci, hippurate hydrolysis by group B streptococci, and bile-esculin reaction for group D streptococci. Enterococcal group D streptococci were differentiated from non-enterococcal group D streptococci by 6.5% NaCl tolerance. Two other categories of streptococci resulted: beta-hemolytic streptococci non-groups A, B, or D; and alpha- or nonhemolytic streptococci, not enterococci, not further identified (viridans streptococci). The tests were used as a battery and not as single entities. In this manner more than 99% of the group A, 99% of the group B, 81% of the beta-hemolytic streptococci non-group A, B, or D, 99% of the group D enterococci, 97% of the group D non-enterococci, and 94% of the viridans streptococci were correctly identified.
149 citations
References
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TL;DR: A method is described for performing type-specific anti-M precipitin tests on group A hemolytic streptococci in 1 mm. capillary pipettes that now seems to be practical.
Abstract: A method is described for performing type-specific anti-M precipitin tests on group A hemolytic streptococci in 1 mm. capillary pipettes. These tests require so much less precipitating serum than was formerly used that the method now seems to be practical.
574 citations
127 citations
TL;DR: Conversion of 2-oxoadipic acid to lysine with Saccharomyces cerevisiae was accomplished in aerated and agitated fermentors under fermentation conditions resembling those used in baker's yeast process to obtain a yeast product containing about 16 per cent hot water-extractable l Lysine.
Abstract: Conversion of 2-oxoadipic acid to lysine with Saccharomyces cerevisiae was accomplished in aerated and agitated fermentors under fermentation conditions resembling those used in baker's yeast process. With this process, a yeast product containing about 16 per cent hot water-extractable lysine (calculated as hydrochloride) was obtained. The conversion efficiency of 2-oxoadipic acid to lysine was about 0.63 (weight basis) in a fermentation medium containing molasses as the sole carbon source. Most of the conversion took place during the growth period. Aeration, concentration of the added 2-oxoadipic acid, and time of precursor addition affected the lysine content and the conversion efficiency.
115 citations
TL;DR: Quite out of line with the usual "Presidential Address" I have chosen to speak to you briefly about some of the authors' work of the past few months, which have concerned the extension of the Lancefield serological technique to those species or types of streptococci which are usually considered "enterococci."
Abstract: Quite out of line with the usual \"Presidential Address\" I have chosen to speak to you briefly about some of our work of the past few months. These studies have concerned the extension of the Lancefield serological technique to those species or types of streptococci which are usually considered \"enterococci,\" as well as to certain related forms. In doing this I must make use of material which belongs quite as much to others as to me. These investigations have been made possible during a comparatively brief span of time, amid many other duties, only by the untiring industry of my associates, Dr. Floyd R. Smith, now of the University of California, and Mr. Charles F. Niven.
92 citations