eMedicine Specialties > Infectious Diseases > Bacterial Infections

Streptococcus Group A Infections: Differential Diagnoses & Workup

Author: Zartash Zafar Khan, MD, Fellow in Infectious Diseases, University of Oklahoma Health Science Center
Coauthor(s): Michelle R Salvaggio, MD, Assistant Professor, Department of Internal Medicine, Section of Infectious Diseases, University of Oklahoma College of Medicine; Medical Director of Infectious Diseases Institute, University of Oklahoma Health Sciences Center; Sat Sharma, MD, FRCPC, Professor and Head, Division of Pulmonary Medicine, Department of Internal Medicine, University of Manitoba; Site Director, Respiratory Medicine, St Boniface General Hospital; Godfrey Harding, MD, FRCP(C), Program Director of Medical Microbiology, Professor, Department of Medicine, Section of Infectious Diseases and Microbiology, St Boniface Hospital, University of Manitoba, Canada
Contributor Information and Disclosures

Updated: Sep 23, 2009

Differential Diagnoses

Acute Rheumatic Fever
Pharyngitis, Bacterial
Cellulitis
Pharyngitis, Viral
Endometritis
Rheumatic Fever
Glomerulonephritis, Acute
Toxic Shock Syndrome
Glomerulonephritis, Poststreptococcal
HIV Disease
Infectious Mononucleosis

Other Problems to Be Considered

Nonstreptococcal infections should be ruled out.

Workup

Laboratory Studies

  • Throat culture
    • Because pharyngitis and tonsillitis may result from various infectious etiologies other than S pyogenes infection, confirm the diagnosis before initiating treatment.
    • Throat culture remains the criterion standard diagnostic test for streptococcal pharyngitis.
    • If performed correctly, culture of a single throat swab on a blood agar plate yields a sensitivity of 90%–95% for the detection of group A streptococci (GAS) in the pharynx.2
    • Some throat culture results are false-positive (eg, not reflecting acute infection but, rather, symptomatic carriage), although all patients with positive culture results are treated with antibiotics.
    • Culture technique
      • GAS grow readily on routine media, but GAS can be isolated more easily using selective media that inhibit the growth of normal pharyngeal flora.
      • Most laboratories inoculate throat swabs on 5% sheep blood agar containing trimethoprim-sulfamethoxazole.
      • A bacitracin disk that contains 0.04 U of bacitracin is also placed at the initial inoculation of the swab.
      • After overnight incubation at a temperature of 35-37°C, beta-hemolytic colonies that grow despite inhibition of the antibiotic disk are presumed to be GAS.
      • Cultures that are negative for GAS after 24 hours are held for another overnight incubation and reexamined.
  • Rapid antigen detection test
    • This test can be completed within minutes.
    • A carbohydrate antigen is detected directly from throat swabs.
    • Presently, the test uses enzyme immunoassay, optical immunoassay, or chemiluminescent DNA probes.
    • These tests yield high specificity (>95%) and sensitivity (80%–90%). Therefore, a negative antigen detection test result should prompt submission of a throat swab for culture.2
  • Blood culture, ASO titer, sputum culture, and tissue culture: These studies should be performed in patients with systemic infections.

In patients with acute pharyngitis, group A beta-hemolytic streptococcal infection should be ruled out. With appropriate antibiotic treatment, the duration of illness is decreased, suppurative complications are prevented, infectivity is decreased, and serious nonsuppurative sequelae (eg, acute rheumatic fever [ARF], poststreptococcal glomerulonephritis [PSGN]) can be prevented. Interestingly, delaying antimicrobial therapy for a short period does not diminish its efficacy in preventing rheumatic fever.15 With rare exceptions, neither posttreatment throat cultures in asymptomatic patients nor routine cultures in asymptomatic family contacts are necessary.16

Imaging Studies

  • CT scanning and MRI are helpful in the diagnosis of cellulitis, myositis, abscess, and necrotizing fasciitis.
  • Chest radiography and CT scanning of the thorax can aid in the diagnosis of pneumonia.

Procedures

  • Surgical debridement is used to manage extensive necrotizing fasciitis.
  • Abscesses, if present, are incised and drained.
  • Intubation is used in patients with airway compromise or acute respiratory distress syndrome associated with TSS or necrotizing pneumonia.
  • A central venous catheter or a wide-bore peripheral line may be needed immediately for fluid resuscitation in patients with shock.

Histologic Findings

Gram stain of tissue shows gram-positive cocci in chains or clusters. Tissue removed for diagnostic or therapeutic measures may show inflammation with polymorph neutrophil infiltration, cytotoxic effects, and/or extensive necrosis. In case of PSGN, immune complex deposition is observed on glomerular basement membrane.


Group A <em>Streptococcus</em> on Gram stain of b...

Group A Streptococcus on Gram stain of blood isolated from a patient who developed toxic shock syndrome.

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Group A <em>Streptococcus</em> on Gram stain of b...

Group A Streptococcus on Gram stain of blood isolated from a patient who developed toxic shock syndrome.

More on Streptococcus Group A Infections

Overview: Streptococcus Group A Infections
Differential Diagnoses & Workup: Streptococcus Group A Infections
Treatment & Medication: Streptococcus Group A Infections
Follow-up: Streptococcus Group A Infections
Multimedia: Streptococcus Group A Infections
References
Further Reading
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References

  1. Schroeder BM. Diagnosis and management of group A streptococcal pharyngitis. Am Fam Physician. Feb 15 2003;67(4):880, 883-4. [Medline]. [Full Text].

  2. [Guideline] Bisno AL, Gerber MA, Gwaltney JM Jr, Kaplan EL, Schwartz RH. Practice guidelines for the diagnosis and management of group A streptococcal pharyngitis. Infectious Diseases Society of America. Clin Infect Dis. Jul 15 2002;35(2):113-25. [Medline].

  3. Graziella O, Roberto N, Christina VH. Nevio Cimolai, ed. Laboratory Diagnosis of Bacterial Infections. Informa Healthcare; 2001:258.

  4. Stevens DL. Streptococcal toxic-shock syndrome: spectrum of disease, pathogenesis, and new concepts in treatment. Emerg Infect Dis. Jul-Sep 1995;1(3):69-78. [Medline].

  5. Musser JM, Hauser AR, Kim MH, Schlievert PM, Nelson K, Selander RK. Streptococcus pyogenes causing toxic-shock-like syndrome and other invasive diseases: clonal diversity and pyrogenic exotoxin expression. Proc Natl Acad Sci U S A. Apr 1 1991;88(7):2668-72. [Medline].

  6. Courtney HS, Ofek I, Hasty DL. M protein mediated adhesion of M type 24 Streptococcus pyogenes stimulates release of interleukin-6 by HEp-2 tissue culture cells. FEMS Microbiol Lett. Jun 1 1997;151(1):65-70. [Medline].

  7. Stevens DL. The toxins of group A streptococcus, the flesh eating bacteria. Immunol Invest. Jan-Feb 1997;26(1-2):129-50. [Medline].

  8. Fraser JD, Proft T. The bacterial superantigen and superantigen-like proteins. Immunol Rev. Oct 2008;225:226-43. [Medline].

  9. Maltezou HC, Tsagris V, Antoniadou A, Galani L, Douros C, Katsarolis I, et al. Evaluation of a rapid antigen detection test in the diagnosis of streptococcal pharyngitis in children and its impact on antibiotic prescription. J Antimicrob Chemother. Sep 30 2008;[Medline].

  10. Goldberg GN, Hansen RC, Lynch PJ. Necrotizing fasciitis in infancy: report of three cases and review of the literature. Pediatr Dermatol. Jul 1984;2(1):55-63. [Medline].

  11. Chopra P, Gulwani H. Pathology and pathogenesis of rheumatic heart disease. Indian J Pathol Microbiol. Oct 2007;50(4):685-97. [Medline].

  12. Snider LA, Swedo SE. Post-streptococcal autoimmune disorders of the central nervous system. Curr Opin Neurol. Jun 2003;16(3):359-65. [Medline].

  13. National Center for Immunization and Respiratory Diseases: Division of Bacterial Diseases. Group A Streptococcal (GAS) Disease. April 3, 2008. [Full Text].

  14. Rodriguez-Iturbe B, Musser JM. The current state of poststreptococcal glomerulonephritis. J Am Soc Nephrol. Oct 2008;19(10):1855-64. [Medline].

  15. Gerber MA, Randolph MF, DeMeo KK, Kaplan EL. Lack of impact of early antibiotic therapy for streptococcal pharyngitis on recurrence rates. J Pediatr. Dec 1990;117(6):853-8. [Medline].

  16. Varosy PD, Newman TB. Acute pharyngitis. N Engl J Med. May 10 2001;344(19):1479; author reply 1480. [Medline].

  17. Casey JR, Pichichero ME. Metaanalysis of short course antibiotic treatment for group a streptococcal tonsillopharyngitis. Pediatr Infect Dis J. Oct 2005;24(10):909-17. [Medline].

  18. Norrby-Teglund A, Muller MP, Mcgeer A. Successful management of severe group A streptococcal soft tissue infections using an aggressive medical regimen including intravenous polyspecific immunoglobulin together with a conservative surgical approach. Scand J Infect Dis. 2005;37(3):166-72. [Medline].

  19. Lamagni T, Efstratiou A, Vuopio-Varkila J. The epidemiology of severe Streptococcus pyogenes associated disease in Europe. Euro Surveill. Sep 1 2005;10(9):[Medline].

  20. Wajima T, Murayama SY, Sunaoshi K, Nakayama E, Sunakawa K, Ubukata K. Distribution of emm type and antibiotic susceptibility of group A streptococci causing invasive and noninvasive disease. J Med Microbiol. Nov 2008;57:1383-8. [Medline].

  21. Group B Streptococcus Surveillance Report 2006. USA: Oregon Department of Human Services; 02/2008. [Full Text].

  22. Callister ME, Wall RA. Descending necrotizing mediastinitis caused by group A streptococcus (serotype M1T1). Scand J Infect Dis. 2001;33(10):771-2. [Medline].

  23. Mani R, Mahadevan A, Pradhan S, Nagarathna S, Srikanth NS, Dias M, et al. Fatal Group A Streptococcal meningitis in an adult. Indian J Med Microbiol. Apr 2007;25(2):169-70. [Medline].

  24. Lurie S, Vaknine H, Izakson A, Levy T, Sadan O, Golan A. Group A Streptococcus causing a life-threatening postpartum necrotizing myometritis: a case report. J Obstet Gynaecol Res. Aug 2008;34(4 Pt 2):645-8. [Medline].

  25. [Best Evidence] Altamimi S, Khalil A, Khalaiwi KA, Milner R, Pusic MV, Al Othman MA. Short versus standard duration antibiotic therapy for acute streptococcal pharyngitis in children. Cochrane Database Syst Rev. Jan 21 2009;CD004872. [Medline].

  26. Currie BJ. Group A streptococcal infections of the skin: molecular advances but limited therapeutic progress. Curr Opin Infect Dis. Apr 2006;19(2):132-138. [Medline].

  27. Dale RC. Post-streptococcal autoimmune disorders of the central nervous system. Dev Med Child Neurol. Nov 2005;47(11):785-91. [Medline].

  28. Doctor A, Harper MB, Fleisher GR. Group A beta-hemolytic streptococcal bacteremia: historical overview, changing incidence, and recent association with varicella. Pediatrics. Sep 1995;96(3 Pt 1):428-33. [Medline].

  29. [Best Evidence] Falagas ME, Vouloumanou EK, Matthaiou DK, Kapaskelis AM, Karageorgopoulos DE. Effectiveness and safety of short-course vs long-course antibiotic therapy for group a beta hemolytic streptococcal tonsillopharyngitis: a meta-analysis of randomized trials. Mayo Clin Proc. Aug 2008;83(8):880-9. [Medline].

  30. Gibofsky A, Zabriskie JB. Rheumatic fever: new insights into an old disease. Bull Rheum Dis. Nov 1993;42(7):5-7. [Medline].

  31. Holm SE, Norrby A, Bergholm AM, Norgren M. Aspects of pathogenesis of serious group A streptococcal infections in Sweden, 1988-1989. J Infect Dis. Jul 1992;166(1):31-7. [Medline].

  32. Kaplan EL, Johnson DR. Eradication of group A streptococci from the upper respiratory tract by amoxicillin with clavulanate after oral penicillin V treatment failure. J Pediatr. Aug 1988;113(2):400-3. [Medline].

  33. Lamagni TL, Efstratiou A, Vuopio-Varkila J, Jasir A, Schalén C. The epidemiology of severe Streptococcus pyogenes associated disease in Europe. Euro Surveill. Sep 2005;10(9):179-84. [Medline].

  34. Marcus RH, Sareli P, Pocock WA, Barlow JB. The spectrum of severe rheumatic mitral valve disease in a developing country. Correlations among clinical presentation, surgical pathologic findings, and hemodynamic sequelae. Ann Intern Med. Feb 1 1994;120(3):177-83. [Medline].

  35. [Best Evidence] Meury SN, Erb T, Schaad UB, Heininger U. Randomized, comparative efficacy trial of oral penicillin versus cefuroxime for perianal streptococcal dermatitis in children. J Pediatr. Dec 2008;153(6):799-802. [Medline].

  36. Norrby-Teglund A, Muller MP, Mcgeer A, Gan BS, Guru V, Bohnen J, et al. Successful management of severe group A streptococcal soft tissue infections using an aggressive medical regimen including intravenous polyspecific immunoglobulin together with a conservative surgical approach. Scand J Infect Dis. 2005;37(3):166-72. [Medline].

  37. Pichichero ME. Group A streptococcal tonsillopharyngitis: cost-effective diagnosis and treatment. Ann Emerg Med. Mar 1995;25(3):390-403. [Medline].

  38. Pichichero ME, Disney FA, Talpey WB, et al. Adverse and beneficial effects of immediate treatment of Group A beta- hemolytic streptococcal pharyngitis with penicillin. Pediatr Infect Dis J. Jul 1987;6(7):635-43. [Medline].

  39. Powis J, McGeer A, Duncan C. Prevalence and characterization of invasive isolates of Streptococcus pyogenes with reduced susceptibility to fluoroquinolones. Antimicrob Agents Chemother. May 2005;49(5):2130-2. [Medline].

  40. Randolph MF, Gerber MA, DeMeo KK, Wright L. Effect of antibiotic therapy on the clinical course of streptococcal pharyngitis. J Pediatr. Jun 1985;106(6):870-5. [Medline].

  41. Smith A, Lamagni TL, Oliver I. Invasive group A streptococcal disease: should close contacts routinely receive antibiotic prophylaxis?. Lancet Infect Dis. Aug 2005;5(8):494-500. [Medline].

  42. Stevens DL. Invasive group A streptococcus infections. Clin Infect Dis. Jan 1992;14(1):2-11. [Medline].

  43. Stevens DL, Tanner MH, Winship J, et al. Severe group A streptococcal infections associated with a toxic shock- like syndrome and scarlet fever toxin A. N Engl J Med. Jul 6 1989;321(1):1-7. [Medline].

  44. Wilson P, Tierney L. Lemierre syndrome caused by Streptococcus pyogenes. Clin Infect Dis. Oct 15 2005;41(8):1208-9. [Medline].

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Further Reading

  • Stevens DL, Kaplan EL, eds. Streptococcal Infections: Clinical Aspects, Microbiology, and Molecular Pathogenesis. 1st ed. Oxford University Press; 2000.

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Keywords

Streptococcus group A infections, group A Streptococcus, group A streptococci, group A streptococcal infection, GAS infection, group A strep, strep throat, streptococci, Streptococcus, Streptococcus pyogenes, S pyogenes, gram-positive cocci, wound infection, acute rheumatic fever, ARF, acute glomerulonephritis, scarlet fever, pharyngitis, impetigo, tonsillopharyngeal cellulitis, tonsillopharyngeal abscess, otitis media, sinusitis, necrotizing fasciitis, streptococcal bacteremia, meningitis, brain abscess, gangrene, toxic shock syndrome, flesh-eating bacteria

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Contributor Information and Disclosures

Author

Zartash Zafar Khan, MD, Fellow in Infectious Diseases, University of Oklahoma Health Science Center
Zartash Zafar Khan, MD is a member of the following medical societies: American College of Physicians, Infectious Diseases Society of America, and International Society for Infectious Diseases
Disclosure: Nothing to disclose.

Coauthor(s)

Michelle R Salvaggio, MD, Assistant Professor, Department of Internal Medicine, Section of Infectious Diseases, University of Oklahoma College of Medicine; Medical Director of Infectious Diseases Institute, University of Oklahoma Health Sciences Center
Michelle R Salvaggio, MD is a member of the following medical societies: American College of Physicians and Infectious Diseases Society of America
Disclosure: Merck Honoraria Speaking and teaching

Sat Sharma, MD, FRCPC, Professor and Head, Division of Pulmonary Medicine, Department of Internal Medicine, University of Manitoba; Site Director, Respiratory Medicine, St Boniface General Hospital
Sat Sharma, MD, FRCPC is a member of the following medical societies: American Academy of Sleep Medicine, American College of Chest Physicians, American College of Physicians-American Society of Internal Medicine, American Thoracic Society, Canadian Medical Association, Royal College of Physicians and Surgeons of Canada, Royal Society of Medicine, Society of Critical Care Medicine, and World Medical Association
Disclosure: Nothing to disclose.

Godfrey Harding, MD, FRCP(C), Program Director of Medical Microbiology, Professor, Department of Medicine, Section of Infectious Diseases and Microbiology, St Boniface Hospital, University of Manitoba, Canada
Godfrey Harding, MD, FRCP(C) is a member of the following medical societies: American College of Physicians, American Society for Microbiology, Canadian Infectious Disease Society, Canadian Medical Association, Infectious Diseases Society of America, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.

Medical Editor

Douglas A Drevets, MD, Assistant Professor, Department of Medicine, Section of Infectious Disease, Oklahoma University Health Sciences Center
Douglas A Drevets, MD is a member of the following medical societies: American Association of Immunologists, American Society for Microbiology, Central Society for Clinical Research, and Christian Medical & Dental Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

John L Brusch, MD, FACP, Assistant Professor of Medicine, Harvard Medical School; Consulting Staff, Department of Medicine and Infectious Disease Service, Cambridge Health Alliance
John L Brusch, MD, FACP is a member of the following medical societies: American College of Physicians and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

CME Editor

Eleftherios Mylonakis, MD, Clinical and Research Fellow, Department of Internal Medicine, Division of Infectious Diseases, Massachusetts General Hospital
Eleftherios Mylonakis, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Society for Microbiology, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Chief Editor

Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital
Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

 
 
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