Abstract and Introduction
Abstract
Appropriate use of antimicrobials in health care continues to be a challenge. Reliable and reproducible antimicrobial susceptibility testing methods are necessary to provide the clinician with valuable information that can be translated into positive clinical outcomes at the bedside. However, there are nuances with these testing methods that, if unrecognized, could lead to misinterpretation of results and inappropriate antibiotic selection. This primer describes the common antimicrobial susceptibility tests used in the clinical microbiology laboratory and reviews how subtle differences in testing methods and technique can influence reported results. Clinicians who have a thorough understanding of qualitative and quantitative methods, automated susceptibility testing systems, and commonly used screening and confirmatory tests for antibiotic-resistant organisms can strengthen institutional antibiotic stewardship programs and improve patient outcomes.
Introduction
In January 2007, the Infectious Diseases Society of America, in conjunction with the Society for Healthcare Epidemiology, released guidelines for developing an institutional program to enhance antimicrobial stewardship. These guidelines underscore the need for accurate and reproducible identification of microorganisms and antibiotic susceptibilities. This is integral to the care of patients with infectious diseases and plays a critical role in antimicrobial stewardship and epidemiologic investigations.
The clinician who has an advanced knowledge of antimicrobials, coupled with an understanding of commonly used microbiology testing methods, can be effective in improving antimicrobial utilization and optimizing patient care. These skills are particularly relevant today and can help combat increased antimicrobial resistance in the hospital and community settings. The purposes of this review are to help pharmacists gain a basic understanding of common antimicrobial susceptibility tests used in the clinical microbiology laboratory, and to demonstrate how differences in testing can influence therapeutic choices for treating infectious diseases.