1/ To evaluate if empirical antibiotic prescription on admission to our intensive care unit (ICU) respects the local recommendations for antibiotic prescription and to identify predictors of nonadherence to these guidelines. 2/ To assess whether nonadherence to the guidelines is associated with increased in-hospital mortality due to the initial infection.

This was a prospective six-month observational study performed in a 14-bed medical ICU. Patients were included if they received curative antibiotic therapy on admission. Respect of the local treatment recommendations was evaluated according to adherence to the local empirical guidelines defined in a 80-page booklet which is given in our hospital to every physician.

Among 132 antibiotic prescriptions, 21 (16%) were unjustified (absence of infection), 17 (13%) were microbiologically documented at admission, and nine (7%) were given for infections from unknown origin. Among the 85 (64%) empirical prescriptions that could be evaluated for adherence to local recommendations, nine (11%) were inappropriate and 76 (89%) appropriate. In univariate analysis hospital-acquired infection was the sole predictor of inappropriate treatment (p = 0.0475). Independent predictors of in-hospital mortality due to the initial infection were inappropriate empirical treatment (odds ratio [OR] = 14.64, 95% confidence interval [CI]: 2.17–98.97; p = 0.006), prescription of fluoroquinolones (OR = 8.22, 95% CI: 1.88–35.95; p = 0.005) and a higher Simplified Acute Physiology Score II score (per one-point increment (OR = 1.04, 95% CI: 1.01–1.07; p = 0.02).

Nonadherence to local empirical antibiotic therapy guidelines was associated with increased in-hospital mortality due to the initial infection.