Table 2.

Multivariable Cox hazard models for the emergence of resistance to any of the four study drugsa

AntibioticEvents (no./total Rx)Multivariable model
HR (95% CI)P value
Culturing scoreNI2.5 (1.1–6.0)0.04
Aminoglycosides13/77 0.8 (0.4–2.0)0.8
Ceftazidime10/1250.7 (0.3–1.7)0.4
Ciprofloxacin12/98 0.8 (0.3–2.0)0.6
Imipenem11/37 2.8 (1.2–6.6)0.02
Piperacillin9/91 1.7 (0.7–4.1)0.3
  • a Rx, treatment; CI, confidence interval; NI, not included.