Fig. 2: Development of Agr dysfunctionality and impact of antibiotic treatment during device- and non-device-associated infection.

a Experimental setup. Female, 6–8 weeks old C57BL/6 were used. For antibiotic treatment, mice received antibiotics starting on day 6 after infection (catheter and skin abscess models) every 24 h for 3 days until the end of the experiment. Controls received no antibiotic. Mice received intraperitoneal injections of 0.25 ml containing 0.3 mg ml⁻¹ Van (3.75 mg kg⁻¹) or oral doses of 0.4 ml containing 0.04 mg ml⁻¹ Lev (0.8 mg kg⁻¹). All mice in one infection type were infected with the same CFU (skin abscess, ~1 × 10⁷ CFU; catheter infection, 1 × 10³–10⁴ CFU with actual adherent bacterial numbers tested.) b, c Results obtained with infection by S. aureus LAC wild-type with and without antibiotics. d, e Results obtained with infection by S. aureus LAC wild-type versus isogenic Δagr mutant. f, g Results obtained with infection by S. aureus LAC Δagr with and without antibiotics. n = 6 (b, d, f); n = 8 (c, e, g). h Representative infected or control (no infection) catheter pieces stained with PI or WGA-Alexa FluorTM 350. Statistical analysis is 1-way ANOVA (b, f) or Kruskal–Wallis (c, g), with Dunnett’s post-tests versus data obtained with wild-type control, Mann–Whitney test (d), and unpaired, two-tailed t-test (e). Parametric versus non-parametric tests were chosen based on normal distribution (Shapiro–Wilk) tests for the data in the respective comparisons. Error bars show the geometric mean and geometric SD.