43rd ICAAC
A meeting of the American Society for Microbiology

September 14-17, 2003, Chicago, IL


For more information on any presentation at the 43rd ICAAC contact Jim Sliwa, ASM Office of Communications at jsliwa@asmusa.org



EMBARGOED UNTIL:  Wednesday, September 17, 9:00 a.m.

(Session 217, Paper 2089)

John Quale
SUNY Health Sci. Ctr.
Brooklyn, NY, United States
Phone: 718-270-2148


Increased usage of antibiotics has been correlated with the emergence of antibiotic resistance. Attempts have been made to diminish the problem of antibiotic-resistant bacteria in hospitals by reducing or changing antibiotic prescribing habits. Several studies have developed interventional programs that imposed hospital-wide antibiotic restriction policies. These studies have generally demonstrated the greatest success, with decreases in antibiotic expenditures and improvement in antibiotic susceptibility rates of several problematic bacteria without affecting infection-related mortality.

Other studies have employed changes in antibiotic usage, along with infection control efforts, to limit the spread of specifically targeted resistant bacteria in hospitals. For example, reducing cephalosporin usage has been associated with decreasing rates with cephalosporin-resistant Klebsiella. Unfortunately, emergence of other resistant bacteria has occurred in some of these studies. It remains controversial whether changing antibiotic usage patterns in hospitals can reduce the spread of vancomycin-resistant enterococci. A fairly consistent relationship has been observed with clindamycin usage and antibiotic-associated colitis, and reducing clindamycin usage has helped control outbreaks. In only a few studies are antibiotic expenditures reported; pharmacy costs were generally unchanged or increased. However, the healthcare savings from having fewer patients with resistant bacterial infections may more than offset the increased pharmacy costs. Reducing or changing antibiotic usage may be a useful supplement to infection control efforts in controlling the spread of certain antibiotic-resistant bacteria acquired in the hospital. Employing this strategy requires careful analysis of the mechanisms of resistance of the targeted bacteria, the effectiveness and cost of alternative agents, and the potential for emergence of other resistant pathogens.

Several recent studies have employed the concept of "cycling" antibiotics in an attempt to limit the development of resistance. Some of these studies have noted decreases in certain infections due to resistant bacteria; however, no changes have occurred in other studies, and the costs of such programs are largely unknown. The use of computers to improve antibiotic prescribing has been documented and may be a promising modality to reduce excessive antibiotic usage.

Most studies analyzing the effect of changing antibiotic usage with resistance patterns have been limited by the relatively short duration of the study. In addition, virtually all studies have confounding variables that may affect the results. For example, educational interventions and infection control protocols are often included in programs designed to limit antibiotic resistance, and ascribing successful outcomes solely to changes in antibiotic usage may be misleading. Additional studies are required to determine if the observed changes in resistance patterns following formulary changes are long lasting and cost-effective.