TABLE 2

Descriptive statistics and adjusted odds ratios for antibiotic exposure in patients with ESBL-producing, AmpC-producing, and susceptible infections in previous 30 days, 90 days, and by antibiotic category

Time of exposure, drug categoryaNo. (%)Adjusted relative risk ratio (95% CI)b
ESBL n = 210AmpC n = 94Controls n = 900ESBL vs controlAmpC vs control
30 days before culture
    Any antibiotic100 (48)32 (34)200 (22)2.19 (1.48–3.23)1.12 (0.65–1.91)
Broad-spectrum beta-lactams33 (16)11 (12)52 (6)1.98 (1.15–3.40)1.88 (0.86–4.11)
    Third-generation cephalosporins14 (7)8 (9)19 (2)2.32 (1.09–4.93)4.47 (1.75–11.41)
    Carbapenems3 (1)1 (1)3 (0)2.35 (0.45–12.37)2.06 (0.18–23.25)
    Cefepime and/or BL/BLIs24 (11)4 (4)34 (4)2.01 (1.07–3.74)0.88 (0.28–2.77)
Anaerobic agents19 (9)3 (3)43 (5)1.20 (0.65–2.20)0.40 (0.12–1.37)
Aminoglycosides10 (4)1 (1)22 (2)0.89 (0.37–2.12)0.37 (0.05–2.98)
Fluoroquinolones7 (3)3 (3)12 (1)1.62 (0.58–4.50)1.71 (0.42–6.89)
TMP-SMX44 (21)19 (20)74 (8)1.81 (1.11–2.96)1.69 (0.88–3.23)
90 days before culture
    Any antibiotic120 (57)45 (48)289 (32)1.91 (1.31–2.79)1.03 (0.62–1.73)
Broad-spectrum beta-lactams49 (23)25 (27)109 (12)1.31 (0.84–2.05)1.91 (1.07–3.41)
    Third-generation cephalosporins21 (10)20 (21)62 (7)0.92 (0.53–1.60)2.68 (1.45–4.94)
    Carbapenems6 (3)4 (4)14 (2)1.04 (0.37–2.90)1.85 (0.53–6.48)
    Cefepime and/or BL/BLIs37 (18)11 (12)62 (7)1.80 (1.07–3.02)1.30 (0.60–2.81)
Anaerobic agents30 (14)12 (13)80 (9)1.08 (0.64–1.78)0.96 (0.47–1.98)
Aminoglycosides13 (6)6 (6)38 (4)0.61 (0.30–1.28)1.06 (0.38–2.94)
Fluoroquinolones14 (7)5 (5)22 (2)1.76 (0.83–3.74)1.30 (0.44–3.82)
TMP-SMX51 (24)25 (27)101 (11)1.53 (0.97–2.41)1.62 (0.90–2.92)
  • a BL/BLIs, beta-lactams/beta-lactamase inhibitors; TMP-SMX, trimethoprim-sulfamethoxazole.

  • b Multinomial logistic regression was performed controlling for age, sex, previous hospitalization in the last year, presence of an indwelling device, underlying medical conditions, and immunosuppression as defined in Table 1.