Table Of ContentAntimicrobial
Susceptibility
Testing Protocols
Antimicrobial
Susceptibility
Testing Protocols
Edited by
Richard Schwalbe
Lynn Steele-Moore
Avery C. Goodwin
Boca Raton London New York
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Library of Congress Cataloging-in-Publication Data
Antimicrobial susceptibility testing protocols / editors, Richard Schwalbe, Lynn Steele-Moore, and
Avery C. Goodwin.
p. ; cm.
Includes bibliographical references and index.
ISBN-13: 978-0-8247-4100-6 (alk. paper)
ISBN-10: 0-8247-4100-5 (alk. paper)
1. Microbial sensitivity tests. 2. Drug resistance in microorganisms. I. Schwalbe, Richard. II.
Steele-Moore, Lynn. III. Goodwin, Avery C.
[DNLM: 1. Microbial Sensitivity Tests--methods. 2. Microbial Sensitivity Tests--standards.
3. Anti-Bacterial Agents. 4. Antifungal Agents. 5. Drug Resistance, Fungal. 6. Drug Resistance,
Microbial. QW 25.5.M6 A631 2007]
QR69.A57A63 2007
616.9’041--dc22 2007005182
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Dedication
This book is dedicated to Dr. Richard Steven Schwalbe,
who passed away September 1, 1998, before our textbook was completed.
All of the contributors to Antimicrobial Susceptibility Testing Protocols
respectfully and lovingly present our work as a token of our admiration
to Rick and in the hope that through our efforts we may carry on his
passion and love of susceptibility testing and microbiology.
l’chaim my friend...I miss you.
Preface
Recent reports in the lay press describing bacterial resistance to multiple antibiotics serve to
emphasize the importance of accurate susceptibility testing. The clinical microbiology laboratory
is often a sentinel for detection of drug-resistant microorganisms. Timely notification of suscepti-
bility results to clinicians can result in initiation or alteration of antimicrobial chemotherapy and
thus improve patient care. Standardized protocols require continual scrutiny to detect emerging
phenotypic resistance patterns.
The aim of Susceptibility Testing Protocols is twofold: one is to present a comprehensive, up-
to-date procedural manual that can be used by a wide variety of laboratory workers. The second
objective is to delineate the role of the clinical microbiology laboratory in integrated patient care.
Many protocols that are presented are an extrapolation of procedures approved by the Clinical and
Laboratory Standards Institute (CLSI). New procedures that are (at present) nonstandardized are
also described.
The first section of this manual addresses the basic susceptibility disciplines that are already
in place in many clinical microbiology laboratories. These include disk diffusion, macro- and
microbroth dilution, agar dilution, and the gradient method. Step-by-step protocols are provided.
Emphasis is placed on optimizing procedures for detection of resistant microorganisms. A chapter
is devoted to automated susceptibility testing, introducing the systems that are currently available
for purchase, including recent laboratory evaluations, and presents an algorithm that can be followed
by laboratory workers who are considering purchasing a new automated system.
The second section is devoted to descriptions of susceptibility protocols that may be performed
by a subset of laboratories, whether as reference centers or as part of a research protocol. Specialized
protocols such as surveillance procedures for detection of antibiotic-resistant bacteria, serum bac-
tericidal assays, time-kill curves, population analysis, and synergy testing are discussed. Emphasis
in this section is on clear descriptions of methods leading to reproducible results.
The final section of this manual includes a series of chapters designed to be used as reference
sources. Additional chapters focus on antibiotic development and design, use of an antibiogram,
and the interactions of the clinical microbiology laboratory with ancillary areas such as hospital
pharmacy, infectious disease personnel, and infection control. A table of antibiotic classes and
common “bug–drug” susceptibilities are also included.
This manual is directed to personnel engaged in the laboratory disciplines that perform in vitro
susceptibility testing, including clinical microbiology, food and agriculture microbiology, pharma-
ceuticals research, and other applied and basic research environments. It is meant to be used as a
bench manual. References are supplied at the end of each chapter to provide additional sources of
information to those individuals wishing to pursue a specific topic in greater detail.
Antibacterial Susceptibility Testing Protocols differs from other available sources of information
by its scope. Its aim is to combine an updated series of laboratory-based techniques and charts
within the context of the role of clinical microbiology in modern medicine.
We would like to acknowledge Debbi Reader Covey for her secretarial assistance and unwa-
vering support. Most of all, we would like to thank Dr. Richard S. Schwalbe for many, many things
and for the great person he was.
Lynn Steele-Moore
Avery C. Goodwin, Ph.D.
Editors
Rick Schwalbe was the director of clinical microbiology at the University of Maryland Medical
Systems and the director of clinical microbiology and virology at the Veteran’s Administration
Medical Center in Baltimore, Maryland. He was associate professor of pathology at the University
of Maryland School of Medicine. At the time of his death he was president of the Maryland ASM.
He served on the editoral board of Antimicrobial Agents and Chemotherapy and had over 100
publications.
Lynn Steele-Moore was the manager of Dr. William J. Holloway’s Infectious Disease Laboratory
at Christiana Care Health Services in Wilmington, Delaware, for 22 years. She currently is employed
by the U.S. Food and Drug Administration in Silver Spring, Maryland. Lynn and the late Dr. Richard
Schwalbe collaborated on many projects, this text being one of them. Unfortunately, Dr. Schwalbe
passed away before the text was completed. However, his contributions can be seen throughout the
text with chapters written by many of his friends. We all lovingly dedicate this text to our beloved
friend, Rick Schwalbe.
Avery C. Goodwin worked at GlaxoSmithKline on the development of antimicrobial drugs. He is
currently employed by the U.S. Food and Drug Administration in Silver Spring, Maryland, as a
microbiology reviewer in the Division of Anti-Infective and Ophthalmology Products.
Description:The clinical microbiology laboratory is often a sentinel for the detection of drug resistant strains of microorganisms. Standardized protocols require continual scrutiny to detect emerging phenotypic resistance patterns. The timely notification of clinicians with susceptibility results can initiat
