Treatment for Skin Infections Caused by Streptococcus anginosus
For skin infections caused by Streptococcus anginosus, penicillin is the drug of choice, with alternatives including clindamycin or a first-generation cephalosporin depending on infection severity and patient factors. 1
First-Line Treatment Options
- Mild infections: Oral penicillin or amoxicillin is the preferred treatment for uncomplicated skin infections caused by Streptococcus anginosus, which remains highly susceptible to penicillins 1
- Moderate to severe infections: For more serious infections, parenteral therapy with penicillin G or ampicillin is recommended 1, 2
- Amoxicillin is FDA-approved for skin and skin structure infections due to susceptible strains of Streptococcus species (α- and β-hemolytic isolates) 3
Alternative Treatments
- For penicillin-allergic patients: Clindamycin is an excellent alternative with good activity against S. anginosus group organisms 1, 4
- First-generation cephalosporins (cefazolin, cephalexin) can be used for non-severe reactions to penicillin, but are contraindicated in patients with immediate hypersensitivity reactions 5, 2
- Vancomycin should be reserved for patients with severe penicillin allergy or treatment failures 2
Treatment Duration
- Treatment should continue for 7-14 days based on clinical response 2
- For any infection caused by streptococcal species, a minimum of 10 days of treatment is recommended to prevent complications such as acute rheumatic fever 3
Special Considerations
- S. anginosus group organisms often cause polymicrobial infections (70% of cases), frequently with gram-negative anaerobes and Enterobacteriaceae 6
- For polymicrobial infections involving S. anginosus, broader coverage may be necessary with agents such as ampicillin-sulbactam or piperacillin-tazobactam 2
- Despite their ability to form abscesses, skin infections with S. anginosus generally have a low mortality rate (3%) 6
Management of Abscesses
- Any abscess formation requires incision and drainage as the primary intervention 2
- For abscesses with systemic signs of infection, antimicrobial therapy should accompany drainage 2
- Cultures from abscesses should be obtained to guide antimicrobial therapy, especially in patients with severe infection or those not responding to initial treatment 2
Monitoring and Follow-up
- Patients should be reevaluated within 24-48 hours to verify clinical response 2
- If there is progression despite appropriate antibiotics, consider:
Important Caveats
- Although intermediate resistance to penicillin has been reported in some S. anginosus isolates (5.6%), the vast majority remain highly susceptible 4
- Resistance to erythromycin (17.1%) and clindamycin (16.6%) has been reported, so susceptibility testing is valuable when available 4
- S. anginosus bacteremia can rarely be associated with deeper infections including endocarditis or underlying conditions such as colon cancer, requiring thorough evaluation in bacteremic patients 7