Identifying Rothia dentocariosa T w o PAPERS in this issue (1,2) concern cases of bacterial endocarditis caused by Rothia dentocariosa, an aerobic, nonmotile, non-spore-forming, pleomorphic, gram-positive coccal to rod-shaped bacterium (see Figure 1) often encountered by healthy medical students working with organisms from swabs of their throats (as part of a laboratory exercise called "the throat unknown"). The number of these off-white, smooth and creamy to rough and wrinkled colonies found by instructors examining primary outgrowths from the students' agar plates of rabbit's blood (inoculated from throat swabbings) has increased noticeably since our teaching laboratories obtained incubators with a controlled C0 2 -in-air atmosphere. Rothia dentocariosa is a bacterium that, along with Bacterionema matruchotii, Streptococcus mutans, and other organisms, is often associated with dental caries. Perhaps the distinguishing features of R. dentocariosa are most simply presented by describing the path a student must follow to be sure that an unknown organism, X, from the oropharynx is R. dentocariosa rather than Actinomyces viscosus, Arachnia propionica, Bacterionema matruchotii, Bifidobacterium sp., Corynebacterium diphtheriae, C. pseudodiphtheriticum (Hoffmani), C. xerosis, Lactobacillus, or Nocardia asteroides (3). Although these various genera may readily be characterized on the basis of some combination of cell-wall mucopeptide (peptidoglycan), cell-wall sugars, or cell-wall lipids, they are not so readily separated by biochemical tests. Yet the average laboratory still identifies bacteria by carrying out a series of so-called biochemical tests (Table 1). In identifying R. dentocariosa the student begins with the fact that there has been isolated in pure culture a markedly pleomorphic, aerobic, gram-positive rod that is catalase-positive. This eliminates the need to consider that organism X might be anaerobic Bifidobacterium or one of the weakly catalase-positive lactobacilli. Since the latter need exogenous hemin to synthesize catalase, the fact that X produces catalase in the absence of a source of hemin rules out Lactobacillus. Only one member of the genus Actinomyces is catalase positive: A. viscosus. Of the strains of A. viscosus thus far described (4), most ferment lactose and none ferments mannitol. Strain X ferments neither of these sugars. Thus, Actinomyces is ruled out. Next is considered the possibility of bacterium X being Arachnia propionica, no strains of which produce catalase and all strains of which ferment both lactose and mannitol. Next comes the candidate Bacterionema matruchotii, most strains of which are lactose and mannitol negative and are said to be characterized by "whip handle cells" and to produce metachromatic granules. Organism X does not produce "whip handle" cells (Figure 1) but does exhibit the peculiarity of growing as rodlike forms on agar and as speroidal forms in broth. N o metachromatic granules can be found in its cells. 736
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Figure 1A. Cells of Rothia dentocariosa growing on agar in an atmosphere of 5 % C 0 2 in air. B. Cells of R. dentocariosa grown on agar in air. Arrows indicate spheroidal cells, which predominate when the organism is cultivated in broth. (Micrographs courtesy of Dr. Kwang-Shin Kim; bar = 2.5 u.m.)
The findings in the paper by Scharfen (8) (References 3 of Pape and colleagues [1] and Schafer and associates [2] herein) are brought to the attention of the students, and they are asked to consider R. dentocariosa as a microbe capable of producing lesions. Those microbes that give rise to pathologic conditions by virtue of colonizing a heart valve must be able to withstand temperatures of 37 °C and not be inhibited by various molecules occurring in the circulating fluids of the host. Many bacteria and fungi lack these two properties. Many generally innocuous organisms possess them. For example, the yeast, Lodderomyces longisporus, found in soil, on preparations of orange pulp, in pickled cucumbers, on or about fingernails, and in human feces (3, 9), has been the cause of endocarditis in heroin addicts (10, 11). Its haploid form, Candida parapsilosis, tolerates temperatures of 37 °C and can grow on the valves of the human heart, taking nourishment from circulating plasma. While clearly this yeast gains entry to the bloodstream through the agency of syringe and needle, it is not known whether the yeast comes there from batches of heroin, the container in which the heroin is packaged, or the skin(s) of the add i c t s ) . Rothia dentocariosa is also a generally innocuous organism and widely distributed among humans. In
Thus, B. matruchotii is ruled out. Eventually, in his or her final report, the student characterizes R. dentocariosa in a way that distinguishes it from other catalase-positive, lactose-negative organisms that might be recovered from the human oropharynx (Table 1). (One interesting observation made early by one of our students was that Rothia would grow on chocolate tellurite plates in the presence of C 0 2 but not in the presence of air. In the case of the strain A T C C 17931 [Rothia dentocariosa, neotype], growth on tellurite seems to take place in an atmosphere of C O / N but not C O / a i r . ) When all of the reports for the "throat unknown" have been turned in by the students and digested by the instructors, there is sometimes a discussion session on the collective throat flora. At this time it is pointed out, when relevant, that R. dentocariosa has long been associated with dental plaques (5) and that cells of this microbe can accumulate calcium phosphate (calculus) intracellularly and extracellularly in vitro (6). A quotation from the 8th edition of Bergey's Manual (4) seems to indicate that R. dentocariosa is of little other significance: "Abcess formation has been demonstrated experimentally in mice (Roth and Flanagan, 1969). N o natural infections reported in man or animals" (7).
Table 1 . Biochemical Reactions Useful in the Identification of Rothia
Catalase Production*
Actinomyces viscosus Arachnid propionica Rothia dentocariosa Bacterionema matruchotii Corynebacterium diphtheriae C. pseudodiphtheriticum C. xerosis Nocardia asteroides
+ —
+ + + + + +
dentocariosa.
Fermentation of Glucose
Lactose
Mannitol
+ + + + +
et +
_
-
+
—
— — —
+
— — —
Sucrose Trehalose
+ + + +
e-
+
—
e + + e
— — —
PyraOrnizinthine/ Xylose amidase Lysine Decarboxylases
_ — — — —
+ + + + -
+ + +
— — — — —
+
Metachromatic Granules
+ + et + + + + +
Urease CoccalSperoidal Cells in Broth
— — —
e -
+ — +
— 0
+
— 0
* In the absence of exogenous hemin. Additional information for the characterization of Rothia can be found in Reference 1 of the paper by Pape and colleagues (1) and in References 1, 2, and 6 of the paper by Schafer and associates (2) in this issue. t Circled + or — indicates occasional exceptions. These data have been assembled from Reference 4 and from unpublished information from our laboratory. X Some stains, for example ATCC 17931, produce no metachromatic granules. Editorial Notes
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many persons the load ofR. dentocariosa is high; in them there would seem a good chance that injury from dental manipulation, cutting nutshells, or jagged toast might introduce enough Rothia to allow eventual seeding of an internal site. In future presentations of endocarditis due to Rothia, it would be worth knowing whether the buccal cavities of the patients were heavily or moderately colonized with R. dentocariosa and whether the general properties and serologic type(s) of the R. dentocariosa isolated from the blood were the same as those of the organisms predominating in the mouths of the patients. Some strains of R. dentocariosa serotype 2 produce (in media containing sucrose) an extracellular levan, a polymer of fructose (5). Levan-producing strains are easily detected as mucoid colonies on sucrose agar plates. This property (or its lack), along with sensitivities and resistances to antibiotics, provides an additional marker by which particular strains of R. dentocariosa can be recognized. ( L A N E BARKSDALE, PH.D.; Department
of
Microbiology,
New York University School of Medicine and Medical Center; New York, New York) References 1. P A P E J, SINGER C, K I E H N TE, L E E BJ, A R M S T R O N G D. Infective endo-
carditis caused by Rothia dentocariosa. Ann Intern Med. 1979;91:946-7. 2. SCHAFER FJ, W I N G EJ, N O R D E N CW. Infectious endocarditis caused by Roth/a dentocariosa. Ann Intern Med. 1979;91:947-8. 3. E M M O N S CW, B I N F O R D CH, U T Z JP, K W O N - C H U N G KJ. Medical
4.
5. 6. 7. 8.
9. 10.
My-
cology. 3rd ed. Philadelphia: Lea and Febiger; 1977:200. BUCHANAN RE, GIBBONS NE, eds. Bergey's Manual of Determinative Bacteriology. 8th ed. Baltimore: Williams and Wilkins Company; 1974:681. LESHER RJ, GERENCSER VF. Levan production by a strain of Rothia: activation of complement resulting in cytotoxicity for human gingival cells. J Dent Res. 1977;56:1097-105. SIDAWAY DA. A microbiological study of dental calculus: II. The in vitro calcification of microorganisms from dental calculus. / Peridont Res. 1978;13:360-6. R O T H G D , FLANAGAN V. The pathogenicity of Rothia dentocariosa inoculated into mice. J Dent Res. 1969;48:957-8. SCHARFEN J. Untraditional glucose fermenting actinomycetes as human pathogens: II. Rothia dentocariosa as a cause of abdominal actinomycosis and a pathogen for mice. Zentralbl Bakteriol [Orig A]. 1975;233:8092. LODDER J, K R E G E R - V A N R I J N, eds. The Yeasts: A Taxonomic Study. 2nd ed. Amsterdam: North-Holland Publishing Company; 1970:403, 1022. POLAYES SH, EMMONS CW. Final report on the identification of the organism of the previously reported case of subacute endocarditis and systemic mycosis (Monilia). JAMA. 1941;117:1533-4.
11. W I K L E R A, WILLIX^MS EG, D O U G L A S ED, E M M O N S CW, D U N N RC.
Mycotic endocarditis. JAMA.
1942;119:333-6.
© 1979 American College of Physicians
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November 1979 • Annals of Internal Medicine • Volume 91 • Number 5
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November 1 979 • Annals of Internal Medicine • Volume 91 • Number 5
Downloaded from https://annals.org by Karolinska Institute user on 01/16/2019
Figure 1A. Cells of Rothia dentocariosa growing on agar in an atmosphere of 5 % C 0 2 in air. B. Cells of R. dentocariosa grown on agar in air. Arrows indicate spheroidal cells, which predominate when the organism is cultivated in broth. (Micrographs courtesy of Dr. Kwang-Shin Kim; bar = 2.5 u.m.)
The findings in the paper by Scharfen (8) (References 3 of Pape and colleagues [1] and Schafer and associates [2] herein) are brought to the attention of the students, and they are asked to consider R. dentocariosa as a microbe capable of producing lesions. Those microbes that give rise to pathologic conditions by virtue of colonizing a heart valve must be able to withstand temperatures of 37 °C and not be inhibited by various molecules occurring in the circulating fluids of the host. Many bacteria and fungi lack these two properties. Many generally innocuous organisms possess them. For example, the yeast, Lodderomyces longisporus, found in soil, on preparations of orange pulp, in pickled cucumbers, on or about fingernails, and in human feces (3, 9), has been the cause of endocarditis in heroin addicts (10, 11). Its haploid form, Candida parapsilosis, tolerates temperatures of 37 °C and can grow on the valves of the human heart, taking nourishment from circulating plasma. While clearly this yeast gains entry to the bloodstream through the agency of syringe and needle, it is not known whether the yeast comes there from batches of heroin, the container in which the heroin is packaged, or the skin(s) of the add i c t s ) . Rothia dentocariosa is also a generally innocuous organism and widely distributed among humans. In
Thus, B. matruchotii is ruled out. Eventually, in his or her final report, the student characterizes R. dentocariosa in a way that distinguishes it from other catalase-positive, lactose-negative organisms that might be recovered from the human oropharynx (Table 1). (One interesting observation made early by one of our students was that Rothia would grow on chocolate tellurite plates in the presence of C 0 2 but not in the presence of air. In the case of the strain A T C C 17931 [Rothia dentocariosa, neotype], growth on tellurite seems to take place in an atmosphere of C O / N but not C O / a i r . ) When all of the reports for the "throat unknown" have been turned in by the students and digested by the instructors, there is sometimes a discussion session on the collective throat flora. At this time it is pointed out, when relevant, that R. dentocariosa has long been associated with dental plaques (5) and that cells of this microbe can accumulate calcium phosphate (calculus) intracellularly and extracellularly in vitro (6). A quotation from the 8th edition of Bergey's Manual (4) seems to indicate that R. dentocariosa is of little other significance: "Abcess formation has been demonstrated experimentally in mice (Roth and Flanagan, 1969). N o natural infections reported in man or animals" (7).
Table 1 . Biochemical Reactions Useful in the Identification of Rothia
Catalase Production*
Actinomyces viscosus Arachnid propionica Rothia dentocariosa Bacterionema matruchotii Corynebacterium diphtheriae C. pseudodiphtheriticum C. xerosis Nocardia asteroides
+ —
+ + + + + +
dentocariosa.
Fermentation of Glucose
Lactose
Mannitol
+ + + + +
et +
_
-
+
—
— — —
+
— — —
Sucrose Trehalose
+ + + +
e-
+
—
e + + e
— — —
PyraOrnizinthine/ Xylose amidase Lysine Decarboxylases
_ — — — —
+ + + + -
+ + +
— — — — —
+
Metachromatic Granules
+ + et + + + + +
Urease CoccalSperoidal Cells in Broth
— — —
e -
+ — +
— 0
+
— 0
* In the absence of exogenous hemin. Additional information for the characterization of Rothia can be found in Reference 1 of the paper by Pape and colleagues (1) and in References 1, 2, and 6 of the paper by Schafer and associates (2) in this issue. t Circled + or — indicates occasional exceptions. These data have been assembled from Reference 4 and from unpublished information from our laboratory. X Some stains, for example ATCC 17931, produce no metachromatic granules. Editorial Notes
Downloaded from https://annals.org by Karolinska Institute user on 01/16/2019
787
many persons the load ofR. dentocariosa is high; in them there would seem a good chance that injury from dental manipulation, cutting nutshells, or jagged toast might introduce enough Rothia to allow eventual seeding of an internal site. In future presentations of endocarditis due to Rothia, it would be worth knowing whether the buccal cavities of the patients were heavily or moderately colonized with R. dentocariosa and whether the general properties and serologic type(s) of the R. dentocariosa isolated from the blood were the same as those of the organisms predominating in the mouths of the patients. Some strains of R. dentocariosa serotype 2 produce (in media containing sucrose) an extracellular levan, a polymer of fructose (5). Levan-producing strains are easily detected as mucoid colonies on sucrose agar plates. This property (or its lack), along with sensitivities and resistances to antibiotics, provides an additional marker by which particular strains of R. dentocariosa can be recognized. ( L A N E BARKSDALE, PH.D.; Department
of
Microbiology,
New York University School of Medicine and Medical Center; New York, New York) References 1. P A P E J, SINGER C, K I E H N TE, L E E BJ, A R M S T R O N G D. Infective endo-
carditis caused by Rothia dentocariosa. Ann Intern Med. 1979;91:946-7. 2. SCHAFER FJ, W I N G EJ, N O R D E N CW. Infectious endocarditis caused by Roth/a dentocariosa. Ann Intern Med. 1979;91:947-8. 3. E M M O N S CW, B I N F O R D CH, U T Z JP, K W O N - C H U N G KJ. Medical
4.
5. 6. 7. 8.
9. 10.
My-
cology. 3rd ed. Philadelphia: Lea and Febiger; 1977:200. BUCHANAN RE, GIBBONS NE, eds. Bergey's Manual of Determinative Bacteriology. 8th ed. Baltimore: Williams and Wilkins Company; 1974:681. LESHER RJ, GERENCSER VF. Levan production by a strain of Rothia: activation of complement resulting in cytotoxicity for human gingival cells. J Dent Res. 1977;56:1097-105. SIDAWAY DA. A microbiological study of dental calculus: II. The in vitro calcification of microorganisms from dental calculus. / Peridont Res. 1978;13:360-6. R O T H G D , FLANAGAN V. The pathogenicity of Rothia dentocariosa inoculated into mice. J Dent Res. 1969;48:957-8. SCHARFEN J. Untraditional glucose fermenting actinomycetes as human pathogens: II. Rothia dentocariosa as a cause of abdominal actinomycosis and a pathogen for mice. Zentralbl Bakteriol [Orig A]. 1975;233:8092. LODDER J, K R E G E R - V A N R I J N, eds. The Yeasts: A Taxonomic Study. 2nd ed. Amsterdam: North-Holland Publishing Company; 1970:403, 1022. POLAYES SH, EMMONS CW. Final report on the identification of the organism of the previously reported case of subacute endocarditis and systemic mycosis (Monilia). JAMA. 1941;117:1533-4.
11. W I K L E R A, WILLIX^MS EG, D O U G L A S ED, E M M O N S CW, D U N N RC.
Mycotic endocarditis. JAMA.
1942;119:333-6.
© 1979 American College of Physicians
788
November 1979 • Annals of Internal Medicine • Volume 91 • Number 5
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