TABLE 1.

Results of Bivariable Analysis of Risk Factors for Reduced Vancomycin Susceptibility in Staphylococcus aureus Bacteremia

Variable	Case patients (n = 134)	Control patients (n = 258)	OR (95% CI)	P
Hospital length of stay prior to infection, median (IQR), days	0 (0–4)	0 (0–1)	1.00 (0.99–1.01)	.02
Stay at Penn Presbyterian Medical Centera	48 (35.8)	70 (27.1)	1.50 (0.93–2.40)	.08
Nonwhite race	56 (43.4)	129 (51.2)	0.71 (0.45–1.12)	.13
Hospital onset of infectionb	40 (29.8)	60 (23.3)	1.40 (0.85–2.30)	.18
Location in ICU >48 hours prior to infection	23 (17.2)	27 (10.5)	1.77 (0.92–3.37)	.08
Inpatient antimicrobial use in prior 30 days
Vancomycin	19 (14.2)	19 (7.4)	2.08 (1.00–4.32)	.046
Piperacillin/tazobactam	3 (2.2)	1 (0.4)	5.89 (0.47–310.10)	.12
Extended-spectrum cephalosporinc	12 (9.0)	12 (4.6)	2.02 (0.80–5.06)	.12
Aztreonam	3 (2.2)	1 (0.4)	5.89 (0.46–310.10)	.12
Levofloxacin	21 (15.7)	15 (5.8)	3.01 (1.42–6.51)	.003
Aminoglycosided	10 (7.5)	7 (2.7)	2.89 (0.96–9.15)	.04
Metronidazole	14 (10.4)	16 (6.2)	1.76 (0.77–4.00)	.16

NOTE. Data are no. (%) of patients, unless otherwise indicated. Only variables with P less than .20 are shown. The Fisher exact test was used for categorical variables and the Wilcoxon rank-sum test for continuous variables. CI, confidence interval; ICU, intensive care unit; IQR, interquartile range; OR, odds ratio.

^aAs opposed to the Hospital of the University of Pennsylvania.

^bOnset of infection more than 48 hours after hospital admission.

^cCeftriaxone, cefotaxime, or cefepime.

^dAmikacin, gentamicin, tobramycin.