Table 2.
Antimicrobial susceptibility of bloodstream isolates in patients with and without risk factors for third-generation cephalosporin resistance.
| Bacteria | 3GC n (%) | 3GC/FQ n (%) | MD (95% CI) | p | 3GC/AG n (%) | MD (95% CI) | p |
|---|---|---|---|---|---|---|---|
| Enterobacteriaceae | |||||||
| Overall (n = 1063) |
996 (94) | 1022 (96) | 2.4 (1.5, 3.4) | <0.001 | 1028 (97) | 3.0 (2.0, 4.0) | <0.001 |
| No 3GC-R risk factors* (n = 768) | 750 (98) | 760 (99) | 1.3 (0.5, 2.1) | 0.002 | 761 (99) | 1.4 (0.6, 2.3) | <0.001 |
| 3GC-R risk factors* (n = 295) | 247 (84) | 263 (89) | 5.4 (2.8, 8.0) | <0.001 | 268 (91) | 7.1 (4.2, 10.1) | <0.001 |
| Non-fermenting Gram-negative bacilli | |||||||
| Overall (n = 105) |
83 (79) | 99 (94) | 15.2 (8.3, 22.2) | <0.001 | 101 (96) | 17.1 (9.8, 24.5) | <0.001 |
| No recent use of beta-lactams+ (n = 76) |
63 (83) | 71 (93) | 10.5 (3.7, 17.6) | 0.004 | 73 (96) | 13.2 (5.4, 20.9) | 0.001 |
| Recent beta-lactam use+ (n = 29) |
20 (69) | 28 (97) | 27.6 (10.3, 44.9) | 0.003 | 28 (97) | 27.6 (10.3, 44.9) | 0.003 |
| Pseudomonas aeruginosa | |||||||
| Overall (n = 70) |
64 (91) | 70 (100) | 8.6 (1.8, 15.3) | 0.01 | 70 (100) | 8.6 (1.8, 15.3) | 0.01 |
| No recent use of beta-lactams+ (n = 49) |
47 (96) | 49 (100) | 4.1 (-1.7, 9.8) | 0.16 | 49 (100) | 4.1 (-1.7, 9.8) | 0.16 |
| Recent beta-lactam use+ (n = 21) |
17 (81) | 21 (100) | 19.0 (7.1, 37.4) | 0.04 | 21 (100) | 19.0 (7.1, 37.4) | 0.04 |
3GC: Third-generation cephalosporin (ceftriaxone for Enterobacteriaceae and ceftazidime for non-fermenters); FQ: Fluoroquinolone (ciprofloxacin); MD: Mean difference; CI: Confidence interval; AG: Aminoglycoside (gentamicin); 3GC-R: Third-generation cephalosporin resistance. * Risk factors for third-generation cephalosporin resistance include prior beta-lactam or fluoroquinolone use within the past 3 months, prior infections or colonization with extended-spectrum beta-lactamase producing Enterobacteriaceae within the past 12 months, and recent outpatient gastrointestinal or genitourinary procedures within the past one month [20]. + Within 30 days of bloodstream infection.