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Journal of Clinical Microbiology, August 2003, p. 3481-3486, Vol. 41, No. 8
0095-1137/03/$08.00+0 DOI: 10.1128/JCM.41.8.3481-3486.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.
Identification of Streptococcus sanguinis with a PCR-Generated Species-Specific DNA Probe
Yihong Li,1* Yaping Pan,2 Fengxia Qi,3 and Page W. Caufield4
Department of Basic Science and Craniofacial Biology,1
Division of Diagnostics, Infectious Disease and Health Promotion, New York University College of Dentistry, New York, New York,4
Department of Periodontology, Dental School, China Medical University, Shenyang, People's Republic of China,2
Department of Oral Biology and Medicine, University of California at Los Angeles School of Dentistry, Los Angeles, California3
Received 12 February 2003/
Returned for modification 9 April 2003/
Accepted 1 May 2003

ABSTRACT
The objective of the present study was to design a PCR-generated
DNA probe and determine the specificity of the probe for the
identification of clinical isolates of
Streptococcus sanguinis.
To do this, we examined over 200 arbitrarily primed PCR (AP-PCR)
amplicon patterns obtained with DNA from clinical isolates of
S. sanguinis. A 1.6-kb DNA amplicon that was common to all AP-PCR
profiles was extracted from agarose gels and then cloned and
sequenced. A search for a similar sequence in the GenBank database
with the BLASTN program revealed that the 1.6-kb DNA fragment
comprised an intergenic region between two housekeeping genes,
uncC (proton-translocating ATPase) and
murA (UDP-
N-acetylglucosamine
enolpyruvyl transferase). Three digoxigenin-labeled DNA probes
were synthesized on the basis of the sequence of the 1.6-kb
fragment: the sequence of probe SSA-1 contained the proton-translocating
ATPase (
uncC) and the entire intergenic region, the sequence
of probe SSA-2 contained only the intergenic region, and the
sequence of probe SSA-3 contained an internal region of the
murA gene. Dot blot hybridization showed that the three probes
displayed signals for hybridization to both
S. sanguinis strain
ATCC 10556 and the
S. sanguinis clinical isolates. Probe SSA-1,
however, hybridized to DNA from
S. oralis and
S. mitis. Probe
SSA-3 hybridized to DNA from
S. gordonii,
S. mitis,
S. oralis,
S. parasanguinis, and
S. vestibularis. The probe SSA-2-specific
intergenic region appeared to be specific for
S. sanguinis.
The results from this study suggest that probe SSA-2 may serve
as a species-specific DNA probe for the identification of clinical
isolates of
S. sanguinis.

INTRODUCTION
The heterogeneous group of oral streptococci collectively named
Streptococcus sanguinis (formerly
S. sanguis) are members of
the indigenous oral biota colonizing dental plaque (
6,
25).
S. sanguinis first colonizes an infant's oral cavity at about
9 months of age (
8) and may serve a protective or antagonistic
role against the cariogenic bacterium
S. mutans (
8,
26,
27).
On the other hand,
S. sanguinis may also cause life-threatening
bacterial endocarditis (
10) and septicemia (
15).
Previous methods for identifying S. sanguinis are based primarily on physiological and biochemical characteristics. The reliability and reproducibility of the conventional phenotypic identification, however, varied among methodologies and investigators (5, 21). For example, previous studies were unable to demonstrate agreement between the genotypic and phenotypic methods for identifying clinical S. sanguinis isolates (8, 30). Accordingly, other methods are being examined, including those that combine PCR with nucleic acid probes for detection and identification of S. sanguinis and other oral bacteria (14, 17, 19, 22, 23, 29, 35, 36, 37).
In the present study, we used a PCR-based approach to develop a DNA probe for identifying S. sanguinis based on a common amplicon present on arbitrarily primed PCR (AP-PCR) profiles. The specificity of this probe was tested against a panel of previously confirmed clinical isolates of S. sanguinis (8, 30). The results of the study suggest that this species-specific probe may serve as a useful tool in the identification of S. sanguinis from clinical samples.

MATERIALS AND METHODS
Bacterial strains.
Sixteen reference strains obtained from the American Type Culture
Collection (ATCC; Manassas, Va.) were included in this study
(Table
1). Two other reference strains,
S. pneumoniae WU2 and
Escherichia coli JM109, were obtained from J. Yother at the
University of Alabama at Birmingham.
S. sanguinis strain ATCC
10556 was selected as a positive control. Strains representing
other species served as negative controls. An additional 78
clinical isolates of
S. sanguinis that were confirmed to be
S. sanguinis strains by biochemical tests and 16S rRNA gene
(rDNA) sequence analyses in a previous study (
8,
30) were also
included. The 78 clinical isolates with unique genotypes were
collected from 16 individuals who visited the maternity and
pediatric clinics at the Jefferson County Department of Health
in Birmingham, Alabama. The details of the sample collection
procedure and
S. sanguinis isolation have been reported in previous
studies (
8,
30). Briefly, saliva samples and dental plaques
were collected, dispersed, and plated onto MM10-sucrose agar
(
41).
S. sanguinis was initially identified on the basis of
its distinct colony morphology on MM10-sucrose medium (
8,
25,
41), and its identity was then confirmed by biochemical tests
(
30). Sixteen (20%) of those clinical
S. sanguinis isolates
(listed in Table
1) were randomly selected and further confirmed
to be
S. sanguinis according to their 16S rDNA sequences.
Genomic DNA isolation.
Genomic DNA was isolated from overnight cultures grown in Todd-Hewitt
broth at 37°C in an anaerobic chamber (85% N
2, 10% CO
2,
5% H
2) with a commercially available DNA extraction kit (Wizard
Genomic DNA Purification Kit; Promega Corp. Madison, Wis.),
according to the instructions of the manufacturer. Purified
DNA was dissolved in 10 mM Tris-HCl buffer containing 1 mM EDTA
(pH 8.0); the final concentrations were adjusted spectrophotometrically
to 50 µg/ml.
AP-PCR experiments.
AP-PCR was performed with all DNA samples by previously described methods (22, 23, 30). A total of 40 commercially available single-stranded 10-mer oligonucleotide primers (Kit A and Kit B; Operon Technologies, Inc., Alameda, Calif.) were screened for their suitabilities in differentiating S. sanguinis strains from non-S. sanguinis strains. Because primer OPA-02 (5'-TGCCGAGCTG-3') was able to produce discriminative amplification patterns (data not shown), it was selected for use in this study. All amplification reactions were conducted in a thermal cycler (GeneAmp 2400; Applied Biosystems, Foster City, Calif.) with a total volume of 50 µl containing 1x PCR buffer (10 mM Tris-HCl, 50 mM KCl [pH 8.3]), 200 µM each nucleotide, 100 pmol of primer OPA-02, 2.5 U of Taq polymerase, 3.5 mM MgCl2, and 50 ng of purified template DNA. The temperature profile was 40 cycles at 94°C for 1 min, 36°C for 1 min, and 72°C for 1 min, followed by a final extension at 72°C for 5 min. The resulting AP-PCR amplicons were separated on a 1.5% agarose gel in TBE (Tris-borate-EDTA) buffer and stained with an ethidium bromide solution (1 µg/ml). The final images of the gels were captured with a digital camera and saved in the tagged image file format for further comparisons.
DNA cloning and sequencing.
DNA amplification demonstrated that all S. sanguinis strains tested contained a 1,653-bp fragment (Fig. 1). This fragment was excised from the agarose gel and eluted by using the QIAquick gel extraction kit (QIAGEN Inc., Santa Clarita, Calif.). The DNA fragment was cloned (TA cloning kit; Invitrogen, Carlsbad, Calif.) and transformed into E. coli, and the insert was sequenced in both directions. A sequence similarity search of the nonredundant GenBank database was preformed by using BLASTN program (National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Md.) (2). Putative open reading frames (ORFs) were identified by using the ORF Finder program (National Center for Biotechnology Information).
Generation of DNA-based probes and dot hybridization.
The results of the BLASTN search followed by the identification
of ORFs with the ORF Finder revealed that the 1,653-bp amplicon
contained three regions: portions of two housekeeping genes
and an intergenic region. Accordingly, three DNA probes were
designed for PCR amplification of these three regions, as illustrated
in Fig.
2. The sequences and positions of the primers used to
construct the probes are listed in Table
2. The three PCR products
were labeled with digoxigenin, and dot hybridization was conducted
according to the instructions of the manufacturer (Digoxigenin-High
Prime DNA Labeling and Detection Starter Kit I; Roche Molecular
Biochemicals, Indianapolis, Ind.). Briefly, heat-denatured chromosomal
DNA (1 µg) was applied to a positively charged nylon membrane
through the wells of Bio-Dot apparatus (Bio-Rad Laboratories,
Hercules, Calif.). The filter was baked at 120°C for 30
min and then hybridized with a digoxigenin-labeled probe at
68°C (no formamide) or at 42°C (containing 50% formamide),
washed at 68°C in 0.1
x SSC (1
x SSC is 0.15 M NaCl plus 0.015
M sodium citrate) containing 0.1% sodium dodecyl sulfate (highly
stringent conditions), and visualized by colorimetric detection
with nitroblue tetrazolium-5-bromo-4-chloro-3-indolylphosphate.
Primer design.
Three sets of primers were designed on the basis of the sequence
of the 1,653-bp fragment from
S. sanguinis type strain ATCC
10556. The forward primer, primer F1 (5'-GATTGACCAAGAACGCCGGGCT-3'),
was derived from nucleotides (nt) 36 to 57 of the fragment.
The reverse primer, primer R3 (5'-CGCATGATATCAGAGATGCAACCC-3'),
was derived from nt 1618 to 1640 of the fragment. The specificities
of the primers for all 20 reference and 78 clinical strains
were tested. All amplification reactions were performed by a
standardized PCR protocol, as described above, except that the
temperature profile consisted of 30 cycles of denaturation at
95°C for 30 s, annealing at 60°C for 30 s, and extension
at 72°C for 1 min. The PCR products were separated in 1%
agarose gels and stained with ethidium bromide.
Three clinical isolates (isolates UASa11, UASa22, and UASa33) representing three S. sanguinis biovars (30) were selected for sequencing after the amplification. The 1,653-bp amplicons generated by PCR were isolated with the QIAquick PCR purification kit (QIAGENE, Valencia, Calif.) and sequenced in both directions. The sequences were aligned (MacVector, version 7.1.1; Accelrys, Madison, Wis.) to compare the 1,653-bp sequences of the S. sanguinis strains of different biovars with that of S. sanguinis type strain ATCC 10556.
Nucleotide sequence accession number.
The 1,653-bp sequence from S. sanguinis ATCC 10556 is available in the GenBank database under accession number AF343003. The sequence of the intergenic region of S. sanguinis is available in the GenBank database under accession number AY277586.

RESULTS
The AP-PCR fingerprints demonstrated that a 1.6-kb amplicon
could be consistently observed in the PCR profiles of type strain
ATCC 10556 and all other strains of
S. sanguinis tested (Fig.
1). In contrast, this fragment was not present in the AP-PCR
fingerprints of other mitis group streptococcal species. Sequencing
of the 1,653-bp DNA fragment revealed two partial ORFs with
high degrees of similarity to other
Streptococcus species; one
was from nt 1 to 111 and the other was from nt 583 to 1653.
A search with the BLASTN program found that the region from
nt 1 to 111 bore a high degree of similarity (92%) to the distal
portion of the proton-translocating ATPase
uncC gene of
S. sanguinis reported by Quivey et al. (
34) (GenBank accession no.
AF001955).
The second ORF (nt 583 to 1653) closely resembled
murA (UDP-
N-acetylglucosamine
enolpyruvyl transferase) from
S. pneumoniae,
S. pyogenes, and
S. mutans, among others. A putative noncoding intergenic region
was found between the two housekeeping genes.
On the basis of the sequence of the 1.6-kb fragment, three digoxigenin-labeled DNA probes were synthesized: the sequence of probe SSA-1 contained the proton-translocating ATPase (uncC) and the entire intergenic region, the sequence of probe SSA-2 contained only the intergenic region, and the sequence of probe SSA-3 contained an internal region of the murA gene. The stringency of hybridization was examined by dot blot hybridization with the genomic DNA of S. sanguinis and the other species listed in Table 1. The results showed that all three probes hybridized to the DNA of the type strain S. sanguinis ATCC 10556 (Fig. 3A to C). Probe SSA-1 (Fig. 3A) and probe SSA-3 (Fig. 3C) weakly hybridized to most of the Streptococcus species, including S. oralis (ATCC 10557), S. gordonii (ATCC 10558), S. oralis (ATCC 9811), S. parasanguinis (ATCC 15911), and S. vestibularis (ATCC 49124) but did not hybridize to actinomyces, lactobacilli, or E. coli.
Probe SSA-2, whose sequence spans the intergenic region, hybridized
to the genomic DNA of
S. sanguinis ATCC 10556 (Fig.
3B) as well
as to the genomic DNA of all clinical
S. sanguinis isolates
(Fig.
3D). No cross-hybridization was observed with other representative
isolates of common oral streptococci, indicating a high degree
of specificity of probe SSA-2 to
S. sanguinis. An extensive
search of the GenBank database with the probe SSA-2 sequence
failed to reveal similarities to any DNA, with
E value greater
than 0.2. The ORF Finder suggested the presence of a putative
ORF within the intergenic region (nt 285 to 515) which resembled
a histidine kinase from
S. pneumoniae and
S. pyogenes and a
hypothetical protein from
S. pyogenes,
S. mutans, and
S. agalactiae (
E value less than 2e-05). Nonetheless, the identity between
the theoretical protein sequences of the probe and those predicted
from genome sequences did not exceed 31%, and the nucleotide
match was even less. Indeed, the nucleotide sequence of the
intergenic region bore little or no similarity to sequences
in the GenBank and failed to hybridize to probe SSA-2, whose
sequence contains the entire intergenic region.
A set of primers (primers F1 and R3) was designed to test whether the presence of the 1.6-kb fragment could be used to identify strains of S. sanguinis. The results showed that only S. sanguinis isolates (78 strains) exhibited the 1,653-bp fragment on 1% agarose gels, as predicted, and no PCR products were detected among the 20 other species strains tested (data not shown). Furthermore, a specific set of PCR primers (primers F2 and R2) was designed to amplify the 475-bp intergenic region, as shown in Fig. 4. DNA from three biovars of S. sanguinis clinical isolates (30) was amplified by PCR with these primers and then sequenced. Although identical in size, the sequences of the three PCR amplicons showed the presence of 12 to 18 polymorphic sites compared with the sequence of ATCC 10556, with a 4% variation in nucleotide sequence found among the three biovars of S. sanguinis isolates (data not shown).

DISCUSSION
The accurate identification of
S. sanguinis has been problematic.
Conventional identification protocols are usually time-consuming
and exhibit ambiguities when they are used to differentiate
among the members of the mitis group (
21,
32). Several new PCR-based
methods show promise in identifying isolates to the species
level (
1,
11,
12,
20,
35,
43). For example, Garnier and coworkers
(
11) described PCR primers based on internal fragments of the
genes encoding
D-alanine-
D-ligases for the identification of
clinically relevant viridans group streptococcal species. Recently,
Rudney and Larson (
35) developed AP-PCR protocols for the identification
of members of the mitis group, including strains of
S. sanguinis.
However, the use of only the PCR-based typing method proved
ineffective for differentiation of the members of the mitis
group. Thus, the combination of a PCR-based typing method and
DNA-based probe hybridization might increase the overall accuracy
of bacterial species delineation (
35).
The 16S rDNA locus in bacteria has been widely used as a target for PCR primers or probes for the identification of numerous microorganisms in cerebrospinal fluid, the gastrointestinal tract, and other sources (12, 43). Several studies have included the rDNA locus to identify S. sanguinis from clinical specimens (8, 20, 30, 33, 35). The probes that were used were usually based on variable regions within the 16S rDNA (3), but such regions often differ by only a few base pairs, especially among the members of the mitis group (20). In fact, Jacobs et al. (18) reported that the use of oligonucleotide probes specific for the 16S rRNA sequences of S. anginosus, S. constellatus, and S. intermedius resulted in the reaction of a large number of strains with both the S. constellatus- and the S. intermedius-specific probes. Among the members of the mitis group, the degrees of similarity, based on comparison of 16S rDNA sequences, between the species ranged from 96 to 99% (20), indicating an increased risk of false-positive results in hybridization reactions. Therefore, the development of a highly sensitive and specific DNA-based probe assay for the identification of S. sanguinis adds a potentially valuable new tool for the early detection and identification of S. sanguinis infection and colonization. Similar approaches have previously been reported by other investigators and successfully applied to the species identification of several microorganisms, such as Prevotella, Porphyromonas, Legionella, Candida, and Bacteroides (13, 14, 28, 40, 44).
In our study, we demonstrated that a specific PCR-generated probe and a set of primers could identify S. sanguinis from a subset of clinical isolates previously suggested to be members of the S. sanguinis complex. Although our findings show that the specifically designed probe SSA-2 possessed accuracy in discriminating S. sanguinis from the mitis group, further research is needed to determine whether the S. sanguinis-specific PCR probe or primer set described here could yield both a high degree of sensitivity and a high degree of specificity in detecting S. sanguinis from whole plaque samples containing hundreds of different phylotypes or species. One strategy would be to examine plaque samples from pre- and postdentate infants for S. sanguinis, as S. sanguinis has been shown to colonize the oral cavity before the emergence of teeth (6, 8, 24, 38), and then to monitor the oral cavities of infants for colonization with S. sanguinis. This, in turn, might then be used to predict the time to colonization with the mutans group of streptococci (8) and, perhaps, the risk for dental caries (7, 9, 24). Incorporation of a signature sequence unique to S. sanguinis into a microarray-type or reverse checkerboard assay (4, 31, 42) might be a convenient way to assay plaque samples for the presence or absence of S. sanguinis. Also noteworthy is the fact that the presence of S. sanguinis has been shown to be associated with health in periodontal diseases (16), suggesting that its activity is antagonistic against periodontopathogens, similar to that against mutans group streptococci shown previously (8, 16, 39).
In conclusion, because the PCR-generated DNA probes can precisely identify S. sanguinis at the species level, application of these species-specific DNA markers will provide valuable tools for the early detection of S. sanguinis colonization and facilitate epidemiological study of its interaction with other oral microbes associated with caries progression and periodontal diseases.

ACKNOWLEDGMENTS
This study was supported by research grants DE-11147 and DE-09082
from the National Institute of Dental and Craniofacial Research,
National Institutes of Health.

FOOTNOTES
* Corresponding author. Mailing address: Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, 345 E. 24th St., New York, NY 10010. Phone: (212) 998-9607. Fax: (212) 995-4087. E-mail:
yihong.li{at}nyu.edu.


REFERENCES
1 - Alam, S., S. R. Brailsford, R. A. Whiley, and D. Beighton. 1999. PCR-based methods for genotyping viridans group streptococci. J. Clin. Microbiol. 37:2772-2776.[Abstract/Free Full Text]
2 - Altschul, S. F., T. L. Madden, A. A. Schaffer, J. Zhang, Z. Zhang, W. Miller, and D. J. Lipman. 1997. Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucleic Acids Res. 25:3389-3402.[Abstract/Free Full Text]
3 - Amann, R. I., L. Krumholz, and D. A. Stahl. 1990. Fluorescent-oligonucleotide probing of whole cells for determinative, phylogenetic, and environmental studies in microbiology. J. Bacteriol. 172:762-770.[Abstract/Free Full Text]
4 - Becker, M. R., B. J. Paster, E. J. Leys, M. L. Moeschberger, S. G. Kenyon, J. L. Galvin, S. K. Boches, F. E. Dewhirst, and A. L. Griffen. 2002. Molecular analysis of bacterial species associated with childhood caries. J. Clin. Microbiol. 40:1001-1009.[Abstract/Free Full Text]
5 - Beighton, D., J. M. Hardie, and R. A. Whiley. 1991. A scheme for the identification of viridans streptococci. J. Med. Microbiol. 35:367-372.[Abstract/Free Full Text]
6 - Carlsson, J., H. Grahnen, G. Jonsson, and S. Wikner. 1970. Establishment of Streptococcus sanguis in the mouths of infants. Arch. Oral Biol. 15:1143-1148.[CrossRef][Medline]
7 - Caufield, P. W., G. R. Cutter, and A. P. Dasanayake. 1993. Initial acquisition of mutans streptococci by infants: evidence for a discrete window of infectivity. J. Dent. Res. 72:37-45.[Abstract/Free Full Text]
8 - Caufield, P. W., A. P. Dasanayake, Y. Li, Y. Pan, J. Hsu, and J. M. Hardin. 2000. Natural history of Streptococcus sanguinis in the oral cavity of infants: evidence for a discrete window of infectivity. Infect. Immun. 68:4018-4023.[Abstract/Free Full Text]
9 - De Stoppelaar, J. D., J. Van Houte, and O. Backer Dirks. 1969. The relationship between extracellular polysaccharide-producing streptococci and smooth surface caries in 13-year-old children. Caries Res. 3:190-199.[Medline]
10 - Douglas, C. W., J. Heath, K. K. Hampton, and F. E. Preston. 1993. Identity of viridans streptococci isolated from cases of infective endocarditis. J. Med. Microbiol. 39:179-182.[Abstract/Free Full Text]
11 - Garnier, F., G. Gerbaud, P. Courvalin, and M. Galimand. 1997. Identification of clinically relevant viridans group streptococci to the species level by PCR. J. Clin. Microbiol. 35:2337-2341.[Abstract]
12 - Greisen, K., M. Loeffelholz, A. Purohit, and D. Leong. 1994. PCR primers and probes for the 16S rRNA gene of most species of pathogenic bacteria, including bacteria found in cerebrospinal fluid. J. Clin. Microbiol. 32:335-351.[Abstract/Free Full Text]
13 - Guillot, E., and C. Mouton. 1996. A PCR-DNA probe assay specific for Bacteroides forsythus. Mol. Cell. Probes 10:413-421.[CrossRef][Medline]
14 - Guillot, E., and C. Mouton. 1997. PCR-DNA probe assays for identification and detection of Prevotella intermedia sensu stricto and Prevotella nigrescens. J. Clin. Microbiol. 35:1876-1882.[Abstract]
15 - Herzberg, M. C., K. Gong, G. D. MacFarlane, P. R. Erickson, A. H. Soberay, P. H. Krebsbach, G. Manjula, K. Schilling, and W. H. Bowen. 1990. Phenotypic characterization of Streptococcus sanguis virulence factors associated with bacterial endocarditis. Infect. Immun. 58:515-522.[Abstract/Free Full Text]
16 - Hillman, J. D., S. S. Socransky, and M. Shivers. 1985. The relationships between streptococcal species and periodontopathic bacteria in human dental plaque. Arch. Oral Biol. 30:791-795.[CrossRef][Medline]
17 - Ida, H., T. Igarashi, A. Yamamoto, N. Goto, and R. Sasa. 1999. A DNA probe specific to Streptococcus sobrinus. Oral. Microbiol. Immunol. 14:233-237.[CrossRef][Medline]
18 - Jacobs, J. A., C. S. Schot, A. E. Bunschoten, and L. M. Schouls. 1996. Rapid species identification of "Streptococcus milleri" strains by line blot hybridization: identification of a distinct 16S rRNA population closely related to Streptococcus constellatus. J. Clin. Microbiol. 34:1717-1721.[Abstract]
19 - Kaufhold, A., A. Podbielski, G. Baumgarten, M. Blokpoel, J. Top, and L. Schouls. 1994. Rapid typing of group A streptococci by the use of DNA amplification and non-radioactive allele-specific oligonucleotide probes. FEMS Microbiol. Lett. 119:19-25.[CrossRef][Medline]
20 - Kawamura, Y., X. G. Hou, F. Sultana, H. Miura, and T. Ezaki. 1995. Determination of 16S rRNA sequences of Streptococcus mitis and Streptococcus gordonii and phylogenetic relationships among members of the genus Streptococcus. Int. J. Syst. Bacteriol. 45:406-408.[Abstract/Free Full Text]
21 - Kilian, M., L. Mikkelsen, and J. Henrichsen. 1989. Taxonomic study of viridans streptococci: description of Streptococcus gordonii sp. nov. and emended descriptions of Streptococcus sanguis, Streptococcus oralis, and Streptococcus mitis. Int. J. Syst. Bacteriol. 39:471-484.
22 - Li, Y., and P. W. Caufield. 1998. Arbitrarily primed polymerase chain reaction fingerprinting for the genotypic identification of mutans streptococci from humans. Oral Microbiol. Immunol. 13:17-22.[Medline]
23 - Li, Y., P. W. Caufield, I. R. Emanuelsson, and E. Thornqvist. 2001. Differentiation of Streptococcus mutans and Streptococcus sobrinus via genotypic and phenotypic profiles from three different populations. Oral Microbiol. Immunol. 16:16-23.[CrossRef][Medline]
24 - Loesche, W. J., S. Eklund, R. Earnest, and B. Burt. 1984. Longitudinal investigation of bacteriology of human fissure decay: epidemiological studies in molars shortly after eruption. Infect. Immun. 46:765-772.[Abstract/Free Full Text]
25 - Loesche, W. J., J. Rowan, L. H. Straffon, and P. J. Loos. 1975. Association of Streptococcus mutans with human dental decay. Infect. Immun. 11:1252-1260.[Abstract/Free Full Text]
26 - Loesche, W. J., and S. A. Syed. 1973. The predominant cultivable flora of carious plaque and carious dentine. Caries Res. 7:201-216.[Medline]
27 - Loesche, W. J., A. Walenga, and P. Loos. 1973. Recovery of Streptococcus mutans and Streptococcus sanguis from a dental explorer after clinical examinations of single human teeth. Arch. Oral Biol. 18:571-575.[CrossRef][Medline]
28 - Lo Presti, F., S. Riffard, F. Vandenesch, and J. Etienne. 1998. Identification of Legionella species by random amplified polymorphic DNA profiles. J. Clin. Microbiol. 36:3193-3197.[Abstract/Free Full Text]
29 - Menard, C., P. Gosselin, J. F. Duhaime, and C. Mouton. 1994. Polymerase chain reaction using arbitrary primer for the design and construction of a DNA probe specific for Porphyromonas gingivalis. Res. Microbiol. 145:595-602.[Medline]
30 - Pan, Y. P., Y. Li, and P. W. Caufield. 2001. Phenotypic and genotypic diversity of Streptococcus sanguis in infants. Oral Microbiol. Immunol. 16:235-242.[CrossRef][Medline]
31 - Papapanou, P. N., P. N. Madianos, G. Dahlen, and J. Sandros. 1997. "Checkerboard" versus culture: a comparison between two methods for identification of subgingival microbiota. Eur. J. Oral Sci. 105:389-396.[Medline]
32 - Pearce, C., G. H. Bowden, M. Evans, S. P. Fitzsimmons, J. Johnson, M. J. Sheridan, R. Wientzen, and M. F. Cole. 1995. Identification of pioneer viridans streptococci in the oral cavity of human neonates. J. Med. Microbiol. 42:67-72.[Abstract/Free Full Text]
33 - Poyart, C., G. Quesne, S. Coulon, P. Berche, and P. Trieu-Cuot. 1998. Identification of streptococci to species level by sequencing the gene encoding the manganese-dependent superoxide dismutase. J. Clin. Microbiol. 36:41-47.[Abstract/Free Full Text]
34 - Quivey, R. G., Jr., R. C. Faustoferri, W. A. Belli, and J. S. Flores. 1991. Polymerase chain reaction amplification, cloning, sequence determination and homologies of streptococcal ATPase-encoding DNAs. Gene 97:63-68.[CrossRef][Medline]
35 - Rudney, J. D., and C. J. Larson. 1999. Identification of oral mitis group streptococci by arbitrarily primed polymerase chain reaction. Oral Microbiol. Immunol. 14:33-42.[CrossRef][Medline]
36 - Rudney, J. D., E. K. Neuvar, and A. H. Soberay. 1992. Restriction endonuclease-fragment polymorphisms of oral viridans streptococci, compared by conventional and field-inversion gel electrophoresis. J. Dent. Res. 71:1182-1188.[Abstract/Free Full Text]
37 - Schmidhuber, S., W. Ludwig, and K. H. Schleifer. 1988. Construction of a DNA probe for the specific identification of Streptococcus oralis. J. Clin. Microbiol. 26:1042-1044.[Abstract/Free Full Text]
38 - Smith, D. J., J. M. Anderson, W. F. King, J. van Houte, and M. A. Taubman. 1993. Oral streptococcal colonization of infants. Oral Microbiol. Immunol. 8:1-4.[Medline]
39 - Socransky, S. S., A. D. Haffajee, C. Smith, and S. Dibart. 1991. Relation of counts of microbial species to clinical status at the sampled site. J. Clin. Periodontol. 18:766-775.[CrossRef][Medline]
40 - Steffan, P., J. A. Vazquez, D. Boikov, C. Xu, J. D. Sobel, and R. A. Akins. 1997. Identification of Candida species by randomly amplified polymorphic DNA fingerprinting of colony lysates. J. Clin. Microbiol. 35:2031-2039.[Abstract]
41 - Syed, S. A., and W. J. Loesche. 1973. Efficiency of various growth media in recovering oral bacterial flora from human dental plaque. Appl. Microbiol. 26:459-465.[Medline]
42 - Tanner, A. C., P. M. Milgrom, R. Kent, Jr., S. A. Mokeem, R. C. Page, C. A. Riedy, P. Weinstein, and J. Bruss. 2002. The microbiota of young children from tooth and tongue samples. J. Dent. Res. 81:53-57.[Abstract/Free Full Text]
43 - Tannock, G. W., A. Tilsala-Timisjarvi, S. Rodtong, J. Ng, K. Munro, and T. Alatossava. 1999. Identification of Lactobacillus isolates from the gastrointestinal tract, silage, and yoghurt by 16S-23S rRNA gene intergenic spacer region sequence comparisons. Appl. Environ. Microbiol. 65:4264-4267.[Abstract/Free Full Text]
44 - Teng, L. J., P. R. Hsueh, J. C. Tsai, F. L. Chiang, C. Y. Chen, S. W. Ho, and K. T. Luh. 2000. PCR assay for species-specific identification of Bacteroides thetaiotaomicron. J. Clin. Microbiol. 38:1672-1675.[Abstract/Free Full Text]
Journal of Clinical Microbiology, August 2003, p. 3481-3486, Vol. 41, No. 8
0095-1137/03/$08.00+0 DOI: 10.1128/JCM.41.8.3481-3486.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.
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