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group A beta-hemolytic streptococcus

Etiology: - disorders associated with infection a) impetigo b) erysipelas c) toxic shock syndrome d) streptococcal pharyngitis (25% of pharyngitis) [5] Epidemiology: - pharyngeal carriage rate 8-16% children, 2% adults [5] Pathology: 1) virulence factors: - M proteins (80 different types) 2) hematogenous spread - may localize to muscle or fascia without antecedent trauma Laboratory: 1) rapid screen for group A streptococcus [7] 2) negative rapid Strep antigen test followed up by culture for beta-hemolytic streptococcus (gold standard) [6] 3) anti-streptolysin O titer [11] 4) see ARUP consult [8] Complications: - non suppurative a) guttate psoriasis b) scarlet fever c) glomerulonephritis d) erythema nodosum - prodrome of fevers, malaise, arthralgias 1-3 weeks prior to appearance of nodules [11] Differential diagnosis: - formation of skin abscesses, such as furuncles or carbuncles, suggests S aureus Management: 1) penicillin a) prevents non-suppurative sequelae if started within 48 hours b) 10 days of therapy recommended c) no resistant organisms [2] 2) erythromycin in penicillin-allergic patients a) some resistance b) strains resistant to erythromycin are resistant to other macrolides as well (i.e. azithromycin, clarithromycin) 3) cephalosporins may have superior cure rates to pencillin [4] - evidence supporting reduced incidence of complications is lacking 4) beta-lactam antibiotic + clindamycin may reduce mortality in hospitalized patients relatice to beta-lactam antibiotic alone [] 4) contact precautions for invasive disease

Related

Streptococcus group A antigen; Streptococcus pyogenes antigen

Specific

Streptococcus pyogenes

General

beta-hemolytic streptococcus

References

  1. Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 1140
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 16. American College of Physicians, Philadelphia 1998, 2012
  3. Prescriber's Letter 9(5):25 2002
  4. Journal Watch 24(9):73, 2004 Casey JR, Pichichero ME. Meta-analysis of cephalosporin versus penicillin treatment of group A streptococcal tonsillopharyngitis in children. Pediatrics. 2004 Apr;113(4):866-82. PMID: 15060239
  5. Danchin MH et al, Burden of acute sore throat and group A streptococcal pharyngitis in school-aged children and their families in Australia. Pediatrics 2007, 120:950 PMID: 17974731
  6. Journal Watch 23(14):115, 2003 Gieseker KE et al Evaluating the American Academy of Pediatrics diagnostic standard for Streptococcus pyogenes pharyngitis: backup culture versus repeat rapid antigen testing. Pediatrics 111:e666, 2003 PMID: 12777583
  7. Humair JP, Revaz SA, Bovier P, Stalder H. Management of acute pharyngitis in adults: reliability of rapid streptococcal tests and clinical findings. Arch Intern Med. 2006 Mar 27;166(6):640-4. PMID: 16567603
  8. ARUP Consult: Group A Streptococcal Disease The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/streptococcal-disease-group
  9. Siegel JD, Rhinehart E, Jackson M et al 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Health Care Settings. Am J Infect Control. 2007 Dec;35(10 Suppl 2):S65-164 PMID: 18068815
  10. Babiker A, Li X, Lai YL et al. Effectiveness of adjunctive clindamycin in beta-actam antibiotic-treated patients with invasive beta-haemolytic streptococcal infections in US hospitals: A retrospective multicentre cohort study. Lancet Infect Dis 2020 Dec 14; PMID: 33333013 https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30523-5/fulltext
  11. NEJM Knowledge+ Dermatology
  12. Group A Streptococcal Infections https://www.niaid.nih.gov/diseases-conditions/group-streptococcal-infections