Influence of an infectious disease service on antibiotic prescription behavior and selection of multiresistant pathogens.

BACKGROUND A routine infectious disease service was established in January 1998 in order to optimize the antibiotic usage and prescription pattern of a neurologic intensive care unit (NICU). METHODS Treatment guidelines for the most prevalent infections were implemented and individual antibiotic regimes were discussed at the bedside with infectious disease experts. RESULTS This interdisciplinary cooperation reduced the total number of antibiotics prescribed by 38.1%, from 7,789 in 1997 to 4,822 in 1998, without compromising patient outcomes (mortality rate: 22/313 patients in 1997 vs. 32/328 patients in 1998). Total patient days (2,254 days vs. 2,296 days) and average length of stay in the NICU (7.2 days vs. 7.0 days) were comparable. Antimicrobial expenditure decreased by 44.8% (71,680 Euros in 1997 vs 39,567 Euros in 1998). Taking into account the costs for the infectious disease service (approximately 8,000 Euros in 1998), a total saving of 24,113 Euros was made. The dramatic reduction in antibiotic usage (mainly of carbapenems) resulted in a statistically significant decreased isolation of Stenotrophomonas maltophilia (p<0.05), Enterobacter cloacae (p<0.05), multiresistant Pseudomonas aeruginosa (p<0.05) and Candida spp. (p<0.05), without any change in the infection control guidelines. CONCLUSION These data show that an infectious disease service can optimize and reduce antibiotic usage. This results in a decrease in the occurence of multiresistant gram-negative pathogens and Candida spp. in intensive care units and, at the same time, saves costs.