CRC - Antimicrobial Susceptibility Testing Protocols

Organization: CRC
Publication Date: 22 May 2007
Page Count: 430


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 susceptibility 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, upto- 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 bactericidal 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, pharmaceuticals 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 unwavering support. Most of all, we would like to thank Dr. Richard S. Schwalbe for many, many things and for the great person he was.