Escherichia coli Nissle 1917 as adjuvant therapy in patients with chronic bacterial prostatitis: a non-blinded, randomized, controlled trial

Purpose: To evaluate the efficacy and safety of Escherichia coli Nissle 1917 (EcN) in association with levofloxacin in patients with chronic bacterial prostatitis (CBP). Methods: Patients with CBP referred to our clinic from September 2017 to July 2019 were enrolled. At baseline, the symptomatology was assessed with the NIH-Chronic Prostatitis Symptom Index (NIH-CPSI), while the Meares–Stamey test was used to diagnose the infection. Patients were randomized (1:1) in two groups (A and B). All subjects underwent oral administration of Levoxacin® 500 mg once daily for 4 weeks. Only the patients in Group B underwent oral administration of EcN® 320 mg, twice daily for 4 weeks and then once daily for 8 weeks. After 3 months, each patient repeated the NIH-CPSI questionnaire, while the Meares–Stamey test was repeated at 3 and 6 months in patients who reported persistent symptoms. All adverse events (AEs) were recorded. Results: A total of 110 patients were enrolled. After 3 months patients in Group B reported a significantly lower NIH-CPSI score (5.85 ± 3.07 vs. 7.64 ± 3.86; p = 0.009) and biological recurrences rate (9.8 vs. 26.9%; p = 0.043). At 6 months the biological recurrences rate was significantly lower in Group B (8.7 vs. 28.9%; p = 0.038). Only three patients in Group A and six in Group B (p = 0.25) complained mild AEs. Conclusions: Combination therapy with EcN and levofloxacin allows a better control of symptoms and biological recurrences in patients with CBP, without worsening the safety of the treatment.