What is the best antibiotic for a urinary tract infection caused by Streptococcus mitis/oralis?

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 17, 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 Guidelines

For a urinary tract infection caused by Streptococcus mitis/oralis, amoxicillin is the best first-line antibiotic choice, given its strong recommendation for complicated UTIs 1. The recommended regimen is amoxicillin 500 mg three times daily for 5-7 days. This choice is based on the European Association of Urology guidelines on urological infections, which suggest using amoxicillin plus an aminoglycoside for complicated UTIs 1.

  • Key considerations for treatment include:
    • Managing any urological abnormality and/or underlying complicating factors, as recommended by the guidelines 1.
    • Ensuring the patient is not allergic to penicillin, as amoxicillin is a penicillin derivative.
    • Considering alternatives such as cephalexin or macrolides like azithromycin if the patient has a penicillin allergy.
  • It's crucial to note that Streptococcus mitis/oralis is an unusual cause of UTIs, typically found in the oral cavity, so its presence in urine may indicate sample contamination or an underlying condition.
  • Completing the full course of antibiotics and ensuring adequate hydration are essential for effective treatment.
  • The guidelines also advise against using ciprofloxacin and other fluoroquinolones for empirical treatment of complicated UTI in certain cases, such as patients from urology departments or those who have used fluoroquinolones in the last 6 months 1.

From the Research

Antibiotic Treatment for Streptococcus mitis/oralis Urinary Tract Infections

  • The best antibiotic for a urinary tract infection caused by Streptococcus mitis/oralis is not explicitly stated in the majority of the provided studies, as they focus on different aspects of infections or other types of bacteria.
  • However, one study 2 reports a case of a urinary tract infection caused by multidrug-resistant Streptococcus mitis/oralis, where the isolated strain showed sensitivity to quinupristin/dalfopristin, vancomycin, and linezolid.
  • Vancomycin was prescribed and proved effective in this case 2, suggesting it as a potential treatment option for Streptococcus mitis/oralis urinary tract infections, especially in cases of multidrug resistance.
  • Other studies 3, 4, 5 discuss the treatment of urinary tract infections with amoxicillin, alone or in combination with clavulanic acid, but these are focused on gram-negative bacteria or do not specifically address Streptococcus mitis/oralis.
  • A study on Streptococcus mitis/oralis causing bloodstream infections in pediatric patients 6 highlights the importance of appropriate antimicrobial treatment based on antibiotic susceptibilities but does not provide direct guidance on urinary tract infection treatment.

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.