Streptococcus Anginosus Group

Streptococcus anginosus group

Background:

Streptococci
———————————————————
>Streptococcus anginosus group (formerly Streptococcus milleri)

   ‘Viridans streptococci’:
     1] Streptococcus intermedius
     2] Streptococcus anginosus
     3] Streptococcus constellatus
>Streptococcus pneumoniae
>Streptobacillus moniliformis
>Streptococcus pyogenes (Groups A, B, C, G, F)
>Streptococcus agalactiae (Group B streptococcus)

Streptococcus anginosus group:

-May be beta-hemolytic or nonhemolytic.
-Part of the human bacteria flora (cultures obtained from mouth, throat, feces, and vagina, other).
Several possible infections are possible based on the frequency of occurence.
-Several antimicrobial resistant strains exist.
Most strains studied have been shown to be largely susceptible to beta-lactam agents e.g. penicillins, cephalosporins
Sulfonamides have no activity.
Most strains are resistant to aminoglycosides

Therapy:

Important considerations: The choice of an agent should be based on local antimicrobial sensitivities, site of infection, cost, and comorbid conditions. Generally, the most common agents/regimens are listed first. Listed dosages may need to be adjusted for renal dysfunction.

Penicillin VK 500mg orally every 6 hours
Penicillin G 2-4 million units IV q4-6h
Cephalexin 500mg orally every 6 hours
Ceftriaxone 1-2 grams IV q24h
Vancomycin 1 gram ivpb q12h (patient-specific dosing required)