LAB WORK
  • Gram +, alpha-hemolytic (partial hemolysis)
  • Occasional contaminant on blood cultures if 1 of 4 bottles positive
  • Not a single species, this is a "viridans group" which includes S. mutans, S. mitis, S. oralis, S. sanginuis, S. gordonii, S. salivarius, S. parasanginous, and Streptococcus anginosus subgroup (this subgroup is more virulent, associated with pyogenic processes and consists of S. intermedius, S. constellatus, S. anginosus)

TREATMENT
  • 1st Line
    • Penicillin G, ampicillin, ceftriaxone (endocarditis)
  • 2nd Line
    • Cefazolin, vancomycin, fluoroquinolones
  • Agents with variable activity (avoid, resistance concerns):
    • ​Tetracyclines
    • Clindamycin
    • Macrolides
  • DO NOT USE BACTRIM - MOST STRAINS ARE RESISTANT

CLINICAL NOTES
  • Penicillin resistance increasing, but is related to penicillin binding protein changes rather than beta-lactamase activity
  • Consider evaluating penicillin MIC on sensitivities
    • If low or intermediate  (> 0.1 to < 2), can use higher dosing of penicillin (example, penicillin G 3-5 MU IV q4h)
    • If high (4 or higher), use an alternative like vancomycin especially in endocarditis.
    • Fluoroquinolones may be an option in non-endocarditis cases