Inadequate treatment of nosocomial infections is associated with certain empiric antibiotic choices

Objective: The purpose of this study was to determine the impact of scheduled changes of antibiotic classes, used for the empirical treatment of suspected or documented Gram-negative bacterial infections, an the occurrence of inadequate antimicrobial treatment of nosocomial infections. Design: Prospective observational study. Setting: Medical (19-bed) and surgical (18-bed) intensive care units in an urban teaching hospital. Patients: A total of 3,668 patients requiring intensive care unit admission were prospectively evaluated during three consecutive time periods. Interventions.. During each time period, one antibiotic class was selected far the empirical treatment of Gram-negative bacterial infections as follows: time period 1 (baseline period) (1,323 patients), ceftazidime; time period 2 (1,243 patients), ciprofloxacin; and time period 3 (1,102 patients), cefepime, Measurements and Main Results: The overall administration of inadequate antimicrobial treatment for nosocomial infections decreased during the course of the study (6.1%, 4.7%, and 4.5%; p = .15). This was primarily because of a statistically significant decrease in the administration of inadequate antibiotic treatment for Gram-negative bacterial infections (4.4%, 2.1%, and 1.6%; p < .001). There were no statistically significant differences in the overall hospital mortality rate among the three time periods (15.6%, 16.4%, and 16.2%; p = .828) despite a significant increase in severity of illness as measured with Acute Physiology and Chronic Health Evaluation (APACHE) II scores (15.3 +/- 7.6, 15.7 +/- 8.0, and 20.7 +/- 8.6; p < .001). The hospital mortality rate decreased significantly during time period 3 (20.6%) compared with time period 1 (28.4%; p < .001) and time period 2 (29.5%; p < .001) for patients with an APACHE II score greater than or equal to 15. Conclusions: These data suggest that scheduled changes of antibiotic classes for the empirical treatment of Gram-negative bacterial infections can reduce the occurrence of inadequate antibiotic treatment for nosacomial infections. Reducing inadequate antibiotic administration may improve the outcomes of critically ill patients with APACHE II scares greater than or equal to 15.