What antibiotic is used to treat Urinary Tract Infection (UTI) caused by Group B Streptococcus (GBS)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: June 8, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the FDA Drug Label

Infections of the genitourinary tract including gonorrhea - E. coli, P. mirabilis, enterococci, Shigella, S. typhosa and other Salmonella and nonpenicillinase-producing N. gonorrhoeae Ampicillin capsules and Ampicillin for oral suspension are indicated in the treatment of infections caused by susceptible strains of the designated organisms listed below

The antibiotic ampicillin is used to treat UTI caused by susceptible strains of certain organisms, but Group B Streptococcus (GBS) is not explicitly listed as one of them in the provided drug label 1. However, since GBS is a type of streptococcus and ampicillin is effective against some streptococci, it may be considered for treatment, but the label does not directly support this use for GBS.

  • Key points:
    • Ampicillin is used for UTI treatment
    • GBS is not explicitly mentioned in the label
    • Ampicillin may be effective against some streptococci, but its use for GBS is not directly supported by the label 1

From the Research

Penicillin G or ampicillin is the first-line antibiotic treatment for urinary tract infections caused by Group B Streptococcus (GBS). For a typical uncomplicated UTI, ampicillin 500 mg orally four times daily for 7-10 days is commonly prescribed 2. In cases of penicillin allergy, alternatives include cephalexin 500 mg orally four times daily, or clindamycin 300 mg orally four times daily for 7-10 days. For more severe infections requiring hospitalization, intravenous ampicillin 2 grams every 4-6 hours may be necessary. GBS remains highly susceptible to beta-lactam antibiotics, which is why penicillins are the preferred treatment, as noted in a recent systematic review 2. These antibiotics work by inhibiting bacterial cell wall synthesis, effectively killing the bacteria. It's essential to complete the full course of antibiotics even if symptoms improve before completion to ensure complete eradication of the infection and prevent recurrence. Adequate hydration is also recommended during treatment to help flush bacteria from the urinary tract.

Some key points to consider when treating UTIs caused by GBS include:

  • The importance of completing the full course of antibiotics to prevent recurrence and ensure complete eradication of the infection
  • The need for adequate hydration to help flush bacteria from the urinary tract
  • The potential for penicillin allergy and the need for alternative treatments, such as cephalexin or clindamycin
  • The effectiveness of beta-lactam antibiotics, such as penicillin and ampicillin, in treating GBS infections, as supported by recent studies 2, 3

It's also worth noting that while there have been reports of reduced susceptibility to beta-lactams, including penicillin, in some countries, GBS remains highly susceptible to these antibiotics, making them the preferred treatment option 3. Additionally, the use of antibiotic susceptibility testing can help guide treatment decisions and ensure the most effective treatment is used 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.