Antibacterial properties of bearberry leaf extracts on most common UTI strains

Aim In order to avoid side effects of antibiotics and increasing numbers of resistant bacteria the use of antibiotics in the treatment of urinary tract infections (UTI) should be limited. According to German treatment guidelines symptomatic treatment might be considered. In this in vitro study the antibacterial properties of three different products containing bearberry leaf extract and one containing powder of rosemary, lovage and centaury were compared.

Materials & methods Minimal inhibitory concentration (MIC) was determined for three bearberry leaf extracts (UROinfekt Filmtabletten, Cystinol akut Dragees, Arctuvan Bärentrauben Filmtabletten) and one product containing rosemary, lovage and centaury powder (Canephron Uno) for the most relevant UTI-causing bacterial strains E. coli, K. pneumoniae, P. mirabilis, E. faecalis, S. saprophyticus, S. aureus. Serial dilutions of the compounds were prepared in 20 ml CAMHA-agar plates, inoculated with bacteria (2x10⁷ CFU/ml) and incubated at 35° C for 20 h.

Results The MIC for the different bacterial strains is comparable for the three bearberry leaf extracts (5.3-9.7 % of the single patient dose for E. coli, P. mirabilis and E. faecalis and 0.8-2.4 % of the single patient dose for S. aureus, S. saprophyticus and K. pneumoniae). In contrast, a 18- to 73-fold higher dose is needed of the powder of rosemary, lovage and centaury to reach the same antibacterial effect.

Conclusion The bacterial strains tested account for 91.3 % for all UTI. The antibacterial effects of bearberry leaf extracts proved them to be a useful tool for UTI treatment to reduce the use of antibiotics.

Publication History

Article published online:
11 October 2022