Skip to main content
  • ASM
    • Antimicrobial Agents and Chemotherapy
    • Applied and Environmental Microbiology
    • Clinical Microbiology Reviews
    • Clinical and Vaccine Immunology
    • EcoSal Plus
    • Eukaryotic Cell
    • Infection and Immunity
    • Journal of Bacteriology
    • Journal of Clinical Microbiology
    • Journal of Microbiology & Biology Education
    • Journal of Virology
    • mBio
    • Microbiology and Molecular Biology Reviews
    • Microbiology Resource Announcements
    • Microbiology Spectrum
    • Molecular and Cellular Biology
    • mSphere
    • mSystems
  • Log in
  • My alerts
  • My Cart

Main menu

  • Home
  • Articles
    • Current Issue
    • Accepted Manuscripts
    • COVID-19 Special Collection
    • Archive
    • Minireviews
  • For Authors
    • Submit a Manuscript
    • Scope
    • Editorial Policy
    • Submission, Review, & Publication Processes
    • Organization and Format
    • Errata, Author Corrections, Retractions
    • Illustrations and Tables
    • Nomenclature
    • Abbreviations and Conventions
    • Publication Fees
    • Ethics Resources and Policies
  • About the Journal
    • About JCM
    • Editor in Chief
    • Editorial Board
    • For Reviewers
    • For the Media
    • For Librarians
    • For Advertisers
    • Alerts
    • RSS
    • FAQ
  • Subscribe
    • Members
    • Institutions
  • ASM
    • Antimicrobial Agents and Chemotherapy
    • Applied and Environmental Microbiology
    • Clinical Microbiology Reviews
    • Clinical and Vaccine Immunology
    • EcoSal Plus
    • Eukaryotic Cell
    • Infection and Immunity
    • Journal of Bacteriology
    • Journal of Clinical Microbiology
    • Journal of Microbiology & Biology Education
    • Journal of Virology
    • mBio
    • Microbiology and Molecular Biology Reviews
    • Microbiology Resource Announcements
    • Microbiology Spectrum
    • Molecular and Cellular Biology
    • mSphere
    • mSystems

User menu

  • Log in
  • My alerts
  • My Cart

Search

  • Advanced search
Journal of Clinical Microbiology
publisher-logosite-logo

Advanced Search

  • Home
  • Articles
    • Current Issue
    • Accepted Manuscripts
    • COVID-19 Special Collection
    • Archive
    • Minireviews
  • For Authors
    • Submit a Manuscript
    • Scope
    • Editorial Policy
    • Submission, Review, & Publication Processes
    • Organization and Format
    • Errata, Author Corrections, Retractions
    • Illustrations and Tables
    • Nomenclature
    • Abbreviations and Conventions
    • Publication Fees
    • Ethics Resources and Policies
  • About the Journal
    • About JCM
    • Editor in Chief
    • Editorial Board
    • For Reviewers
    • For the Media
    • For Librarians
    • For Advertisers
    • Alerts
    • RSS
    • FAQ
  • Subscribe
    • Members
    • Institutions
Bacteriology

Diagnosis of Streptococcal Pharyngitis by Detection of Streptococcus pyogenes in Posterior Pharyngeal versus Oral Cavity Specimens

James W. Fox, Mario J. Marcon, Bema K. Bonsu
James W. Fox
1Departments of Pediatrics, Division of Emergency Medicine
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: foxj@pediatrics.ohio-state.edu
Mario J. Marcon
2Laboratory Medicine, Children's Hospital, Columbus, Ohio
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Bema K. Bonsu
1Departments of Pediatrics, Division of Emergency Medicine
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
DOI: 10.1128/JCM.00797-06
  • Article
  • Figures & Data
  • Info & Metrics
  • PDF
Loading

ABSTRACT

Carbohydrate antigen detection, nucleic acid probe detection, and bacterial culture are commonly used to confirm group A streptococcus (GAS) pharyngitis. Compared to standard throat swab specimens, the sensitivities of these tests with mouth specimens are poor. When testing for GAS pharyngitis, the throat remains the optimum site for sampling.

Streptococcus pyogenes (group A streptococcus [GAS]) causes approximately 15 to 30% of pediatric sore throats (1). Accurate diagnosis permits appropriate administration of antimicrobial therapy to prevent complications, hasten symptom resolution, and reduce the transmission of GAS in the community (7, 12, 13). Unfortunately, clinical evaluation and scoring systems cannot reliably identify patients with streptococcal pharyngitis, necessitating the utilization of laboratory tests (3, 6). While culture of GAS on sheep blood agar medium remains the gold standard for detection of GAS in throat swab specimens (2), newer and more rapid diagnostic tests, including direct carbohydrate antigen and nucleic acid probe detection, are now available.

Current methods of GAS pharyngitis testing rely on swab specimens obtained from the posterior pharynx and tonsils. This convention is based on recommendations published by the Infectious Diseases Society of America (IDSA), which defines specimens obtained from these sites to be the only adequate samples to test for the presence of Streptococcus pyogenes (2). It should be noted, however, that these recommendations are based on two small studies performed more than 20 years ago that evaluated only 32 patients (4, 9). In this study, we investigate the use of newer techniques of rapid direct carbohydrate antigen and nucleic acid probe detection to identify GAS in samples obtained purposively from the oral cavities and posterior pharynges of pediatric patients with sore throats. This comparison is of practical significance because it is often difficult to obtain a well-collected posterior pharyngeal swab specimen from young children.

This study was approved by the Institutional Review Board of Columbus Children's Hospital and conducted with informed consent between September 2004 and February 2005. Fifty-three patients presenting with a chief complaint of sore throat to the Children's Hospital emergency department were enrolled as study subjects. Subjects ranged from 3 to 18 years of age; the only exclusion criterion was prior tonsillectomy.

Each subject underwent two swab collections with a double-swab collection/transport system (COPAN Venturi Transystem; COPAN Diagnostics Inc., Corona, CA). The standard posterior pharyngeal (throat swab) collection technique involved vigorous swab sampling of the posterior pharynx and bilateral tonsillar tissue while avoiding contact with the tongue, buccal surfaces, and lips. The oral cavity (mouth swab) collection technique involved blind sampling of the subject's mouth, targeting the tongue and buccal mucosa. Each subject was asked to rate his/her pain with a validated age-appropriate pain scale after each swab collection (11).

Immediately after sample collection, one swab from each site was used for direct antigen detection with an Abbott Signify Rapid Strep A test (Abbott Laboratories, Abbott Park, IL). Within 24 h, a nucleic acid probe test (Gen-Probe Direct Strep test; Gen-Probe Inc., San Diego, CA) was performed on the remaining throat and mouth swabs according to the manufacturer's instructions, and a broth-enhanced culture for GAS was performed on the pledget from each collection/transport tube system. Briefly, the pledget was placed into LIM broth (Becton Dickinson, Sparks, MD) and incubated overnight at 35°C. A subculture of the broth was performed on SXT blood agar (Becton Dickinson), and the plate was incubated in 5% CO2 at 35°C for 48 h. Beta-hemolytic colonies were identified as GAS by a latex agglutination test (Streptex GAS test; Remel Inc., Lexena, KS). The gold standard for diagnosing GAS pharyngitis was a positive culture or nucleic acid probe of the pharyngeal/tonsillar specimens.

It was determined that 58% (31/53) of subjects had GAS pharyngitis. Only one patient had discordant throat probe and culture results. For testing of throat swab specimens, the sensitivity and specificity were 80.6% and 100%, respectively, for the direct antigen test and 93.3% and 95.7%, respectively, for the nucleic acid probe test. For testing of mouth swab specimens, the sensitivity and specificity were 19.4% and 100%, respectively, for the direct antigen test and 41.9% and 100%, respectively, for the probe test. The sensitivity of enhanced culture performed on mouth swab specimens was 80.6% (Table 1). By pairwise comparison, the sensitivity of tests performed on mouth swabs was lower than the sensitivity of the same tests performed on throat swabs (P < 0.001, analysis of variance for proportions). The level of subject discomfort during collection of mouth swabs was lower than that during collection of throat swabs (data not shown; P < 0.0001, Wilcoxon signed rank sum test).

Throat swab sampling demonstrated superior sensitivity for all GAS detection techniques investigated in this study, substantiating the importance of a well-collected sample from the posterior pharynx when attempting to diagnose GAS pharyngitis. The performances of the direct antigen and nucleic acid probe tests on throat swabs in this study were similar to previously reported data (5, 8, 10). However, the sensitivity of each test (direct antigen, probe, and culture) on mouth swabs was unsatisfactory compared to the recommended throat swab. Notably, the prevalence of GAS pharyngitis in this study population (58%) was higher than that from previously published reports (1). While the positive and negative predictive values of tests may be affected, prevalence does not affect a test's sensitivity and specificity. Although throat sampling is less tolerable to patients, medical personnel should make every effort to obtain samples from the posterior pharynges and tonsils of children with sore throats.

Despite this recommendation, our data suggest that there may be some utility in special circumstances to performing direct antigen tests on swab specimens believed to arise from nonpharyngeal/nontonsillar sites. One such circumstance involves the uncooperative child for whom a “clean” throat swab without oral secretion contamination is impossible to obtain. With excellent specificity, positive direct antigen tests of such samples—collected inadvertently/purposively from the oral cavity—would be sufficient to confirm GAS pharyngitis. A negative test in this situation, however, would not exclude this infection and should prompt additional attempts to sample the posterior pharynx for further testing, empirical treatment with antibiotics, or performance of an enhanced culture on the remaining mouth swab.

In conclusion, our study validates recommendations by the IDSA to obtain a sample from the posterior pharynges and tonsils of patients suspected of having GAS pharyngitis. Traditional as well as modern tests used to detect the presence of GAS in symptomatic children (direct carbohydrate antigen, DNA probe, and sheep blood agar culture) all perform significantly better on specimens obtained from the throat.

View this table:
  • View inline
  • View popup
TABLE 1.

Performance characteristics of culture, direct carbohydrate antigen test, and DNA probe testa

ACKNOWLEDGMENTS

We thank Debbie Goodman, Lori Shuler, Pam Streich, and Marylyn Hribar for their help in completing this study.

There were no potential, perceived, or real conflicts of interest, financial or otherwise, in producing the report. We each accept full responsibility for the report's contents.

FOOTNOTES

    • Received 13 April 2006.
    • Returned for modification 26 April 2006.
    • Accepted 9 May 2006.
  • Copyright © 2006 American Society for Microbiology

REFERENCES

  1. 1.↵
    Bisno, A. L. 1996. Acute pharyngitis. Etiology and diagnosis. Pediatrics97:949-954.
    OpenUrlAbstract/FREE Full Text
  2. 2.↵
    Bisno, A. L., M. A. Gerber, J. M. Gwaltney, E. L. Kaplan, R. H. Schwartz, et al. 2002. Practice guidelines for the diagnosis and management of group A streptococcal pharyngitis. Clin. Infect. Dis.35:113-125.
    OpenUrlCrossRefPubMedWeb of Science
  3. 3.↵
    Breese, B. B., and F. A. Disney. 1954. The accuracy of diagnosis of beta streptococcal infections on clinical grounds. J. Pediatr.44:670-673.
    OpenUrlCrossRefPubMedWeb of Science
  4. 4.↵
    Brien, J. H., and J. W. Bass. 1985. Streptococcal pharyngitis: optimal site for throat culture. J. Pediatr.106:781-783.
    OpenUrlCrossRefPubMedWeb of Science
  5. 5.↵
    Chapin, K. C., P. Blake, and C. D. Wilson. 2002. Performance characteristics and utilization of rapid antigen test, DNA probe, and culture for detection of group A streptococci in an acute care clinic. J. Clin. Microbiol.40:4207-4210.
    OpenUrlAbstract/FREE Full Text
  6. 6.↵
    Cohen, R., C. Levy, P. Ovetchkine, M. Boucherat, C. Weil-Olivier, J. Gaudelus, F. de La Rocque, and E. Bingen. 2004. Evaluation of streptococcal clinical scores, rapid antigen detection tests and cultures for childhood pharyngitis. Eur. J. Pediatr.163:281-282.
    OpenUrlCrossRefPubMed
  7. 7.↵
    Denny, F. W., L. W. Wannamaker, W. R. Brink, C. H. Rammelkamp, and E. A. Custer. 1950. Prevention of rheumatic fever: treatment of the preceding streptococcic infection. JAMA143:151-153.
    OpenUrlCrossRefPubMedWeb of Science
  8. 8.↵
    Gerber, M. A., and S. T. Shulman. 2004. Rapid diagnosis of pharyngitis caused by group A streptococci. Clin. Microbiol. Rev.17:571-580.
    OpenUrlAbstract/FREE Full Text
  9. 9.↵
    Gunn, B. A., R. Mesrobian, J. F. Keiser, and J. Bass. 1985. Cultures of Streptococcus pyogenes from the oropharynx. Lab. Med.16:369-371.
    OpenUrl
  10. 10.↵
    Heiter, B. J., and P. P. Bourbeau. 1993. Comparison of the Gen-Probe Group A Streptococcus Direct Test with culture and a rapid streptococcal antigen detection assay for diagnosis of streptococcal pharyngitis. J. Clin. Microbiol.31:2070-2073.
    OpenUrlAbstract/FREE Full Text
  11. 11.↵
    Keck, J., J. Gerkensmeyer, B. Joyce, and J. Schade. 1996. Reliability and validity of the Faces and Word Descriptor Scales to measure pain in verbal children. J. Pediatr. Nurs.11:368-374.
    OpenUrlCrossRefPubMed
  12. 12.↵
    Krober, M. S., J. W. Bass, and G. N. Michels. 1985. Streptococcal pharyngitis: placebo-controlled double-blind evaluation of clinical response to penicillin therapy. JAMA253:1271-1274.
    OpenUrlCrossRefPubMedWeb of Science
  13. 13.↵
    Randolph M. F., M. A. Gerber, K. K. DeMeo, and L. Wright. 1985. Effect of antibiotic therapy on the clinical course of streptococcal pharyngitis. J. Pediatr.106:870-875.
    OpenUrlCrossRefPubMedWeb of Science
PreviousNext
Back to top
Download PDF
Citation Tools
Diagnosis of Streptococcal Pharyngitis by Detection of Streptococcus pyogenes in Posterior Pharyngeal versus Oral Cavity Specimens
James W. Fox, Mario J. Marcon, Bema K. Bonsu
Journal of Clinical Microbiology Jul 2006, 44 (7) 2593-2594; DOI: 10.1128/JCM.00797-06

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Print

Alerts
Sign In to Email Alerts with your Email Address
Email

Thank you for sharing this Journal of Clinical Microbiology article.

NOTE: We request your email address only to inform the recipient that it was you who recommended this article, and that it is not junk mail. We do not retain these email addresses.

Enter multiple addresses on separate lines or separate them with commas.
Diagnosis of Streptococcal Pharyngitis by Detection of Streptococcus pyogenes in Posterior Pharyngeal versus Oral Cavity Specimens
(Your Name) has forwarded a page to you from Journal of Clinical Microbiology
(Your Name) thought you would be interested in this article in Journal of Clinical Microbiology.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Share
Diagnosis of Streptococcal Pharyngitis by Detection of Streptococcus pyogenes in Posterior Pharyngeal versus Oral Cavity Specimens
James W. Fox, Mario J. Marcon, Bema K. Bonsu
Journal of Clinical Microbiology Jul 2006, 44 (7) 2593-2594; DOI: 10.1128/JCM.00797-06
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
  • Top
  • Article
    • ABSTRACT
    • ACKNOWLEDGMENTS
    • FOOTNOTES
    • REFERENCES
  • Figures & Data
  • Info & Metrics
  • PDF

KEYWORDS

Mouth
pharyngitis
pharynx
Streptococcal Infections
Streptococcus pyogenes

Related Articles

Cited By...

About

  • About JCM
  • Editor in Chief
  • Board of Editors
  • Editor Conflicts of Interest
  • For Reviewers
  • For the Media
  • For Librarians
  • For Advertisers
  • Alerts
  • RSS
  • FAQ
  • Permissions
  • Journal Announcements

Authors

  • ASM Author Center
  • Submit a Manuscript
  • Article Types
  • Resources for Clinical Microbiologists
  • Ethics
  • Contact Us

Follow #JClinMicro

@ASMicrobiology

       

ASM Journals

ASM journals are the most prominent publications in the field, delivering up-to-date and authoritative coverage of both basic and clinical microbiology.

About ASM | Contact Us | Press Room

 

ASM is a member of

Scientific Society Publisher Alliance

 

American Society for Microbiology
1752 N St. NW
Washington, DC 20036
Phone: (202) 737-3600

 

Copyright © 2021 American Society for Microbiology | Privacy Policy | Website feedback

Print ISSN: 0095-1137; Online ISSN: 1098-660X