First-Line Antibiotic for Group B Streptococcal Skin Infections
Penicillin or amoxicillin is the first-line antibiotic choice for Group B streptococcal skin infections, with first-generation cephalosporins (cefazolin IV or cephalexin oral) as equally effective alternatives. 1, 2, 3
Primary Treatment Recommendations
For Non-Severe Infections (Oral Therapy)
- Penicillin V or amoxicillin remains the treatment of choice due to proven efficacy, safety, narrow spectrum, and low cost 2, 3
- Cephalexin (first-generation cephalosporin) is an equally effective alternative for oral therapy 2
- Treatment duration should be 5-10 days for uncomplicated skin infections 2, 3
For Severe Infections (Parenteral Therapy)
- Penicillin G (2-4 million units IV every 4-6 hours) or ampicillin for serious infections 1
- Cefazolin (1 g IV every 8 hours) as an alternative first-generation cephalosporin 1
- Nafcillin or oxacillin (1-2 g IV every 4 hours) are also effective options 1
Penicillin Allergy Considerations
Non-Severe Penicillin Allergy
- Cefazolin is recommended for patients without history of anaphylaxis, angioedema, respiratory distress, or urticaria 1
High-Risk Penicillin Allergy (History of Anaphylaxis)
- Clindamycin (600-900 mg IV every 8 hours) if susceptibility testing confirms sensitivity 1, 2
- Vancomycin (30 mg/kg/day IV in 2 divided doses) if clindamycin resistance is present or susceptibility unknown 1
- Erythromycin is an alternative, though resistance rates are increasing 2, 4
Critical Clinical Considerations
Resistance Patterns
- Group B streptococci remain 100% susceptible to penicillin with no resistance documented over decades 1, 5
- However, 16% resistance to erythromycin and 9% resistance to clindamycin has been documented in invasive Group B strep isolates, making these less reliable empirical alternatives 4
- Susceptibility testing should be performed when using clindamycin or erythromycin for penicillin-allergic patients 1
Mixed Infections Warning
- In older age groups and when clinical distinction between staphylococcal and streptococcal infection is unclear, consider empiric coverage for both organisms with penicillinase-resistant penicillins (dicloxacillin) or first-generation cephalosporins 6
- If MRSA is suspected based on local epidemiology or treatment failure, broader coverage may be needed 1
Adjunctive Measures
- Elevation of the affected limb to promote edema drainage 2
- Treatment of underlying predisposing conditions such as tinea pedis, venous eczema, or interdigital fungal infections to prevent recurrence 2
- Surgical intervention may be required for soft-tissue or bone involvement, particularly in elderly patients 5
Special Populations
Elderly and Immunocompromised Patients
- Group B streptococcal infections carry particularly high mortality in elderly patients over 60 years of age 5
- High-dose penicillin G is recommended due to somewhat higher minimal inhibitory concentrations in serious infections 5
- Early identification and aggressive treatment are critical in patients with diabetes, malignancy, or liver disease 5