The papers assembled in this collection comprise a majority of the oral presentations as well as several poster presentations given at the 22nd Annual Symposium arranged by the Bastern Pennsylvania Branch of the American Society for MicrobioloS)'. The symposium would not be possible without the generous support of the many sponsors (see sponsor list) or without the concerted effort of a11 the Committee members. This Symposium series has evolved into an annual Bastern Pennsylvania Branch ASM event that attracts participants from a wide geographie area. It should be noted that one of the hallmarks of these symposia involves interaction between the presenters and those in attendance. Several authors have altered their by the participants. Therefore, the manuscript that manuscripts based on comments fo11ows should be viewed as a group effort of both the participants and presenters. J ames Poupard Lori Walsh Bruee Kleger ix CONTENTS 1 Introduction 1: CURRENT METHODS The Evolution of Antimicrobial Susceptibility Testing Methods . . . . . . . . . . . . . . . 3 James A. Poupard, Stephen F. Rittenhouse, and Lori R. Walsh Antimicrobial Susceptibility Tests: Testing Methods and Interpretive Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Patrick R. Murray Clinician Utilization of Rapid Antibiotic Susceptibility Data: A Prospective Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Franklin P. Koontz SESSION 2: CONTEMPORARY ISSUES IN SUSCEPTIBILITY TESTING When We Should Be Testing, How Often and What to Report . . . . . . . . . . . . . . . 35 Raymond C. Bartlett Areas of Recent Emphasis of the National Committee for Clinical Laboratory Standards Subcommittee on Antimicrobial Susceptibility Testing . . . . . . . . . . . . . . . . .. . . . . . 61 James H. Jorgensen Non-Traditional Approaches for Quality Control of Antimicrobial Susceptibility Tests . . . . . . . . . . . . . . . . . . . . . . . . .