Effects of various antimicrobial stewardship programs on antimicrobial usage and resistance among common gram-negative bacilli causing health care-associated infections: A multicenter comparison

Abstract

Background: The effects of various antimicrobial stewardship programs (ASPs) on both antibiotic consumption and resistance among different hospitals within the same insurance system have rarely been investigated.

Methods: This 6-year retrospective study included three medical centers with similar facilities and infection control measures in Taiwan. These hospitals used different types of ASPs: one had a hospital-wide preauthorization requirement by infectious diseases physicians for all broad-spectrum antibiotics, covering all intensive care units; the second used the same program, but excluded all intensive care units; and the third used postprescription review only. The nonsusceptibility of unduplicated isolates of gram-negative bacilli causing health care-associated infections and consumption of broad-spectrum antibiotics were analyzed.

Results: Overall, the usage of broad-spectrum antibiotics of all classes escalated significantly over time in all three hospitals, but consumption was lowest under the hospital-wide preauthorization program. Under this ASP, despite a 2-fold increase in the total broad-spectrum antibiotic consumption during study period, some declining trends of resistance were found, including ciprofloxacin-resistant Pseudomonas aeruginosa and Acinetobacter baumannii, and carbapenem-resistant P. aeruginosa. By contrast, the other two hospitals with preauthorization program excluding all intensive care units and postprescription review had similar high broad-spectrum antibiotic consumption, comparable growing trends of resistant strains in general, and the correlations of antibiotic consumption and resistance were basically positive. Carbapenem-resistant A. baumannii increased significantly over time in all three hospitals.

Conclusion: This interhospital comparison suggested that hospital-wide preauthorization program is the most effective to reduce key gram-negative bacilli resistance, with the exception of carbapenem-resistant A. baumannii.

Keywords: Antibiotic consumption; Antibiotic stewardship program; Carbapenem; Gram-negative organisms; Multidrug-resistant organisms.