Fig. 4.

Susceptibility of Borrelia burgdorferi biofilms grown on plastic and collagen-coated surface to antimicrobial agents after a three-day treatment determined by crystal violet assay. Doxycycline (DoxC) was used as a positive control. 1× PBS and 25% alcohol were used as negative controls, respectively. All antibiotics individually as well as in combination were used at a concentration of 10 µg/ml. Stevia A was used at a concentration of 1.2 µg/ml. n = 3 ± SD, ^*p ≤ 0.05, ^**p ≤ 0.01 compared to the control. n = 3 ± SD, ⁺p ≤ 0.05, ⁺⁺p ≤ 0.01 (doxycycline compared to Stevia A). n = 3 ± SD, ^•p ≤ 0.05, ^••p ≤ 0.01 (doxycycline compared to Stevia A). Abbreviations: doxycycline – DoxC, cefoperazone – CefP, daptomycin – DapM