From the Research
For treating Group B Streptococcus (GBS) cystitis in a non-pregnant patient with penicillin allergy, the recommended first-line treatment is trimethoprim-sulfamethoxazole (TMP-SMX) at a dose of 160mg/800mg (one double-strength tablet) twice daily for 5-7 days, as supported by the most recent and highest quality study 1.
Treatment Options
- Alternatively, nitrofurantoin 100mg twice daily for 5-7 days can be used if the patient has normal renal function.
- For patients with severe penicillin allergy, clindamycin 300mg orally four times daily for 7 days is an effective option.
- Fluoroquinolones like ciprofloxacin 500mg twice daily for 7 days can also be used but are generally reserved as second-line due to resistance concerns and side effect profiles.
Importance of Susceptibility Testing
- Before starting treatment, obtaining a urine culture with susceptibility testing is important to confirm the diagnosis and guide therapy if the empiric treatment fails, as noted in 2.
- Patients should be advised to complete the full course of antibiotics even if symptoms resolve earlier, drink plenty of fluids, and return for follow-up if symptoms persist beyond 48-72 hours of treatment.
Considerations for Penicillin Allergy
- It is essential to evaluate the patient's reported penicillin allergy, as most patients who report a penicillin allergy are not truly allergic and would tolerate penicillins if administered, as discussed in 3 and 4.
- Allergy evaluation using a detailed patient history and allergy testing (skin testing and/or oral challenge) when indicated has been shown to be safe and effective, as highlighted in 1 and 5.