Pathogens
Streptococcus pyogenes / Group A Strep

Streptococcus pyogenes / Group A Strep

Precautions

See 'Additional Information'

Susceptibilities

General Information

General

  • Penicillin G or Amoxicillin

Pharyngitis

  • Amoxicillin or Penicillin G x 10 days

Erysipelas/Cellulitis

  • Penicillin G or amoxicillin

Toxic Shock Syndrome (TSS) or Necrotizing Fasciitis

  • Clindamycin + Penicillin G
  • Stop clindamycin once clinically improved for TSS
  • Continue clindamycin for entire treatment duration if necrotizing fasciitis

Bacteremia

  • Clindamycin + Penicillin G
  • Stop clindamycin once blood is cleared

Pneumonia

  • Penicillin G or Amoxicillin

General

  • Beta-lactam allergy: Clindamycin

Pharyngitis

  • Penicillin G benzathine IM x 1 dose - If can't ensure adherence to PO
  • Cephalexin - If amoxicillin within 4 weeks (recurrent disease)
  • Cefdinir or cefuroxime - If allergy to amoxicillin or cephalexin
  • Clindamycin - If unspecified beta-lactam allergy

Erysipelas/Cellulitis

  • Cefazolin - If allergy to Penicillin
  • Clindamycin - If unspecified beta-lactam allergy

Toxic Shock Syndrome

  • Clindamycin + Ceftriaxone - If allergy to penicillin

Pneumonia

  • Cefazolin - If allergy to Penicillin
  • Clindamycin - If unspecified beta-lactam allergy
  • Gram positive cocci in chains, beta-hemolytic
  • Pyrogenic exotoxin producing strains

Respiratory Infections

  • Tonsillopharyngitis (“Strep Throat”): most common in children >3 years old
    • Incubation period: 2-5 days
  • Scarlet fever: in associated w/ pharyngitis, erythematous sandpaper-like rash caused by GAS produced exotoxins
  • Purulent complications: otitis media, sinusitis, peritonsillar and retropharyngeal abscesses, suppurative cervical adenitis

Skin Infections

  • Impetigo: Incubation period 7-10 days
    • Characteristic honeycomb-like crusts after pustular lesions break vs S. aureus paper-like crusts
    • Not associated w/ fever
  • Cellulitis (erysipelas): bright red appearance of skin, demarcation from normal surrounding skin
    • Associated w/ fever
  • Necrotizing fasciitis: infection via trauma to tissue or via bowel flora

Invasive infections

Entry site is skin or mucous membranes

  • Pneumonia and empyema
  • Bacteremia
  • Endocarditis
  • Pericarditis
  • Septic arthritis
  • Osteomyelitis
  • Myositis
  • Surgical site infection
  • Streptococcal toxic shock syndrome (STSS): toxin-producing GAS strains and manifests in acute illness
  • Fever, erythroderma, rapid-onset hypotension, signs of multiorgan involvement

Postinfectious Syndromes

  • Acute rheumatic fever (ARF)
  • Poststreptococcal glomerulonephritis (PSGN)

Precautions

  • School pharyngitis outbreaks due to contact with respiratory secretions
  • Droplet precautions: GAS pharyngitis and pneumonia until 24 hours after appropriate antimicrobial therapy
  • Contact precautions: Burns with secondary GAS infection and extensive draining/cutaneous infection that is not covered or contained by dressings; for 24 hours after appropriate antimicrobial therapy

Treatment Notes

  • Adding Clindamycin for toxic shock syndrome/sepsis: Inhibits protein synthesis to suppress toxin production
  • Linezolid is an alternative to clindamycin for toxin production inhibition
  • Not reasonable to treat colonization unless symptomatic pharyngitis
  • TMP/SMX (Bactrim) may be effective for mild cases of cellulitis if staph is still a concern in the outpatient setting