What is the recommended treatment for group B streptococcal (GBS) pharyngitis?

Treatment for Group B Streptococcal (GBS) Pharyngitis

Penicillin V or amoxicillin is the recommended first-line treatment for Group B streptococcal pharyngitis, with a 10-day course being the standard duration. 1

First-Line Treatment Options

• Penicillin V: 250 mg three times daily or 500 mg twice daily for 10 days (adults)
• Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days

All Group B streptococcal isolates remain universally susceptible to penicillin, ampicillin, cefazolin, cefotaxime, and vancomycin 2, 3. This consistent susceptibility pattern supports the continued use of penicillin or amoxicillin as first-line therapy.

Alternative Options for Penicillin-Allergic Patients

For patients with penicillin allergy, the following alternatives can be considered:

• Clindamycin: 300-450 mg orally three times daily for 10 days 1
• Cephalexin: For patients without immediate hypersensitivity reactions to penicillin

It's important to note that resistance to alternative agents is increasing:

• Clindamycin resistance: 12.7% (increasing from 10.5% to 15.0%) 2
• Erythromycin resistance: 25.6% (increasing from 15.8% to 32.8%) 2

Due to this increasing resistance, erythromycin is no longer recommended as a first alternative for penicillin-allergic patients. Clindamycin is preferred, but susceptibility testing should be performed when possible.

Management of Treatment Failures

For patients who fail initial therapy with penicillin or amoxicillin:

1. Clindamycin: 20-30 mg/kg/day in 3-4 divided doses for 10 days (children); 600 mg/day in 2-4 divided doses for 10 days (adults) 4
2. Amoxicillin/clavulanate: 40 mg/kg/day in 3 divided doses for 10 days 4

For patients with compliance issues or multiple treatment failures, parenteral therapy with benzathine penicillin G may be considered 4.

Duration of Treatment

A full 10-day course of antibiotics is recommended to ensure complete eradication of the organism 1. While shorter courses (5 days) of certain antibiotics like azithromycin have been studied, the evidence is insufficient to recommend shorter courses for GBS pharyngitis.

Prevention of Spread

• Maintain isolation precautions for a minimum of 24 hours after starting effective antibiotic therapy 1
• Healthcare workers with symptomatic GBS infection should be excluded from work until 24 hours of appropriate treatment and resolution of symptoms 1
• Practice good hand hygiene and avoid sharing utensils or drinks with infected individuals 1

Important Considerations

• Unlike Group A streptococcal pharyngitis, Group B streptococcal pharyngitis is less commonly associated with post-infectious sequelae such as rheumatic fever
• However, treatment is still important to prevent complications and reduce transmission
• All GBS isolates remain susceptible to beta-lactam antibiotics, making penicillin and amoxicillin excellent first-line choices 2, 3
• Follow-up cultures are not routinely recommended for patients who have received an adequate course of antimicrobial therapy 4

Remember that while Group A streptococcus is the most common bacterial cause of pharyngitis, Group B streptococcus can also cause pharyngeal infections that require appropriate antibiotic treatment to prevent complications and transmission.