Antimicrobial Stewardship at The Toronto Hospital

Abstract

Infectious diseases continue to plague humankind, and the treatment of infections continues to consume a significant proportion of health care resources. Although antibiotics have saved countless lives and have transformed the treatment of infectious diseases, increasing levels of antibiotic resistance present a serious emerging public health threat. Antibiotic resistance results in morbidity and mortality from treatment failures and increased health care costs (1). Current costs to treat infections with antibiotic-resistant organisms are estimated by the Centers for Disease Control and Prevention, Atlanta, Georgia to be over $4 billion annually in the United States (2). Increasing resistance raises concerns about the inability to treat certain infections, bringing about the dawn of the ‘postantibiotic’ era. Overuse and inappropriate use of antibiotics are widely believed to be responsible for the increasing level of antibiotic resistance (3-5). Although antibiotic resistance is encountered everywhere, particular problems exist in health care institutions. Many of the organisms that are part of the normal flora may pose a significant threat, as an invasive pathogen, to patients whose resistance is lowered by virtue of age, chemotherapy, transplantation or immunosuppression. The hospital milieu, especially in intensive care units, burn units, neonatal units, hematology-oncology units and other special care units, provides an epidemiological pressure cooker for the emergence and dissemination of antibiotic-resistant organisms. The frequent use of antibiotics, high use of invasive devices and frequent hospitalization in these patient populations adds the necessary ingredients to this pressure cooker environment. Approaches to controlling the development and spread of antibiotic-resistant organisms have been outlined in several documents and reports (2,5-10). Three major strategies are employed to achieve this end: surveillance to identify the trends of resistance, improving appropriate antimicrobial usage (antimicrobial stewardship), and reducing cross transmission of multiresistant organisms through enhanced infection control precautions and reducing environmental contamination. These strategies may be considered in the context of the classic host-microbe-drug relationship as depicted in Figure 1. We describe the approaches to antibiotic stewardship that have been used at The Toronto Hospital (TTH) over the past seven years. The Toronto Hospital is a 1200-bed tertiary care medical school-affiliated hospital with over 34,000 visits per year. In 1991, the annual expenditure for antimicrobial agents was over $3 million. At this time the Pharmacy and Therapeutics Committee recommended the creation of a new pharmacy position (Drug Utilization Co-ordinator) to monitor drug use with a focus on appropriate antimicrobial prescribing. The An-