Table 2

Percentages of ESBL-producing E. coli-positive samples and confidence intervals

Sample sourceNo. of samples/total (%) [CI]
FecalBoot swabsDust
Mixed farms
    Cows37/90 (41.1) [31.5–51.4]14/31 (45.2) [29.2–62.2]5/29 (17.2) [7.6–34.6]
    Calves50/89 (56.2) [45.8–66.0]21/30 (70) [52.1–83.3]12/30 (40) [24.6–57.7]
    Beef cattle19/89 (21.4) [14.1–31.0]12/31 (38.7) [23.7–56.2]0/29 (0) [0.0–11.7]
    Sum106/268 (39.6) [33.9–45.5]47/92 (51.1) [41.0–61.1]17/88 (19.3) [12.4–28.8]
Beef cattle farms
    Youngest group12/45 (26.7) [16.0–41.0]3/15 (20) [7.1–45.2]1/15 (6.7) [1.2–29.8]
    Oldest group5/45 (11.1) [4.8–23.5]5/16 (31.3) [14.2–55.6]0/14 (0) [0.0–21.5]
    Sum17/90 (18.9) [12.1–28.2]8/31 (25.8) [13.7–43.3]1/29 (3.5) [0.6–17.2]
Total sum for mixed farms and beef cattle farms123/358 (34.4) [29.6–39.4]55/123 (44.7) [36.2–53.5]18/117 (15.4) [10.0–23.0]
Control group0/33 (0) [0.0–10.4]3/11 (27.3) [9.8–56.6]0/5 (0) [0.0–43.5]