From the Guidelines
Amoxicillin is the first-line oral antibiotic for treating Group B Streptococcus (GBS) cellulitis, with a recommended dose of 500 mg three times daily for 5-10 days. This recommendation is based on the most recent and highest quality study available, which suggests that a 5-day course of antimicrobial therapy is as effective as a 10-day course if clinical improvement has occurred by 5 days 1. For patients with penicillin allergy, clindamycin 300-450 mg four times daily for 5-10 days is an appropriate alternative.
Key Considerations
- Group B strep remains highly susceptible to beta-lactam antibiotics, which is why penicillins are preferred 1.
- These antibiotics work by inhibiting bacterial cell wall synthesis, effectively killing the streptococcal organisms.
- It's essential to complete the full course of antibiotics even if symptoms improve before completion.
- If there's no improvement within 48-72 hours of starting treatment, reassessment is necessary as this may indicate resistance, incorrect diagnosis, or a complication requiring different management.
Treatment Approach
- Oral antibiotics can be used as the initial treatment for typical cases of cellulitis, with amoxicillin being a suitable option 1.
- In more severe cases, initial treatment may involve intravenous antibiotics before transitioning to oral therapy.
- Elevation of the affected area and promoting gravity drainage of the edema and inflammatory substances can also aid in recovery 1.
- Patients should also receive appropriate therapy for any underlying condition that may have predisposed to the infection, such as tinea pedis or venous eczema.
Special Considerations
- Macrolide resistance among group A streptococci has increased regionally in the United States, making it essential to consider alternative treatments in areas with high resistance rates 1.
- Systemic corticosteroids may be considered as an optional adjunct for treatment of uncomplicated cellulitis and erysipelas in selected adult patients, as they have been shown to hasten resolution and shorten healing time 1.
From the FDA Drug Label
Amoxicillin/clavulanic acid has been shown to be active against most isolates of the following bacteria, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section Gram-positive bacteria Staphylococcus aureus Gram-negative bacteria Enterobacter species Escherichia coli Haemophilus influenzae Klebsiella species Moraxella catarrhalis The following in vitro data are available, but their clinical significance is unknown At least 90 percent of the following bacteria exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoint for amoxicillin/clavulanic acid. However, the efficacy of amoxicillin/clavulanic acid in treating clinical infections due to these bacteria has not been established in adequate and well-controlled clinical trials Gram-positive Bacteria Enterococcus faecalis Staphylococcus epidermidis Staphylococcus saprophyticus Streptococcus pneumoniae Streptococcus pyogenes Viridans group Streptococcus Gram-negative Bacteria Eikenella corrodens Proteus mirabilis Anaerobic Bacteria Bacteroides species including Bacteroides fragilis Fusobacterium species Peptostreptococcus species
The FDA drug label does not answer the question.
From the Research
Treatment of Group B Streptococcus (GBS) Cellulitis
- The first-line treatment for GBS cellulitis is typically parenteral antibiotic therapy, with penicillin G being the mainstay of therapy 2, 3.
- For patients who are allergic to penicillin, alternative antibiotics such as vancomycin, clindamycin, or erythromycin may be used 4, 5.
- However, resistance to non-beta-lactam antibiotics, including clindamycin, erythromycin, and fluoroquinolones, has been observed, making antibiotic sensitivity analysis crucial for penicillin-allergic patients 3, 5.
- There is no clear evidence to support the use of a specific oral antibiotic as first-line treatment for GBS cellulitis, as most studies recommend parenteral antibiotic therapy 6, 2, 3.
Antibiotic Susceptibility
- All GBS strains were sensitive to penicillin, ampicillin, and vancomycin in one study 4.
- Resistance to erythromycin and clindamycin was observed in 25% and 13% of GBS strains, respectively, in the same study 4.
- Another study found that 2% of GBS isolates were resistant to erythromycin and 1% were resistant to clindamycin 5.