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Microbiological Assay - 1st Edition - ISBN: 9780123464507, 9780323157094

Microbiological Assay

1st Edition

An Introduction to quantitative principles and Evaluation

Author: William Hewitt
eBook ISBN: 9780323157094
Imprint: Academic Press
Published Date: 28th January 1977
Page Count: 298
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Microbiological Assay: An Introduction to Quantitative Principles and Evaluation aims to provide an introduction to the principles of microbiological assay, assay design, and calculation procedures. Organized into nine chapters, this book begins with the philosophy of biological assay, as well as the method’s basic techniques, principles, mechanization, automation, purpose, reference standards, specifications, and reports. It also looks into the preparation of test solutions of standard and sample. Some chapters follow explaining the specific methods, such as agar diffusion assay and tube assay; others explore the statistical evaluation of these assays. Features of assay design, such as replication, number of dose levels, and spacing of dose levels, are also described. This book will serve as an elementary introduction to this field of interest to help encourage a less empirical approach to the subject.

Table of Contents



Chapter 1 Introduction

1.1 Philosophy of Biological Assay

1.2 Basic Techniques and Principles

1.3 Mechanization and Automation

1.4 Purpose of the Assay

1.5 Reference Standards

1.6 Preparation of Test Solutions of Standard and Sample

1.7 Specifications and Reports


Chapter 2 The Agar Diffusion Assay

2.1 Introduction

2.2 Theory of Zone Formation

2.3 Nature of the Response Curve

2.4 Dose-Response Curves in Practice

2.5 Simple Assay Designs

2.6 Simple Multiple Assay Designs

2.7 Simplification of Computation of the Potency Ratio

2.8 Designs Incorporating Checks for Curvature (Three Dose Levels)

2.9 Designs Incorporating Checks for Curvature (Four Dose Levels)

2.10 Assays by Large Plates—General Principles

2.11 Large Plate Assays Using Latin Square Designs

2.12 Large Plate Assays Using Quasi-Latin Square Designs

2.13 Low-Precision Assays Using Large Plates

2.14 Small Plate Assays Using Interpolation from a Standard Curve

2.15 Missing Values


Chapter 3 Tube Assays Growth-Promoting Substances

3.1 General Principles

3.2 Measurement of Response

3.3 Nonideal Responses

3.4 Slope Ratio Assays—An Unbalanced Design

3.5 Criteria of Validity

3.6 Multiple Linear Regression Equations

3.7 Potency Computation from an Unbalanced Design

3.8 Balanced Slope Ratio Assays with Linearity Check

3.9 Simplified Computation of Potency Ratio from Balanced Assays

3.10 Multiple Assays by the Slope Ratio Method


Chapter 4 Tube Assays for Antibiotics

4.1 General Principles

4.2 Response Curve—Commonly Used Forms of Expression

4.3 Linearization of Dose-Response Relationships—Theoretical Considerations

4.4 Dose-Response Linearization Procedures in Practice

4.5 Potency Estimation by Interpolation from a Standard Curve

4.6 Graphic Estimation of Potency by Probit of Response versus Dose

4.7 Arithmetical Estimation of Potency from an Assay of Balanced Design by Angular Transformation of Response

4.8 Graphic Estimation of Potency Using the Relationship Log Response versus Dose

4.9 Estimation of Potency by Interpolation from a Dose-Response Line Using an Automated System


Chapter 5 Assay of mixtures of Antibiotics

5.1 Occurrence of Mixtures and the Nature of the Problem

5.2 General Techniques

5.3 Comparative Bioautographs

5.4 Quantitative Bioautographs

5.5 Differential Assays


Chapter 6 Evaluation of Parallel Line Assays

6.1 Introduction

6.2 Basic Assumptions for the Statistical Evaluation of Parallel Line Assays

6.3 Evaluation of a Standard Log Dose-Response Curve

6.4 Analysis of Variance to Separate Components Attributable to Various Sources

6.5 Evaluation of a Simple Two Dose Level Assay

6.6 An Alternative Method for Obtaining Confidence Limits

6.7 Evaluation of a Multiple Two Dose Level Assay

6.8 Evaluation of a Three Dose Level Assay

6.9 Evaluation of a Large Plate Assay (Latin Square Design)

6.10 Evaluation of a Large Plate Assay (Quasi-Latin Square Design)

6.11 Evaluation of a Large Plate, Low Precision Assay

6.12 Evaluation of an Assay Incorporating Reference Points—The "FDA" Design

6.13 Evaluation of a Quantitative Bioautograph

6.14 Evaluation of Tube Assays Using Function of Response versus Logarithm of Dose


Chapter 7 Evaluation of Slope Ratio Assays

7.1 Principles of Evaluation

7.2 Evaluation of Simple Slope Ratio Assays

7.3 Evaluation of a Multiple Slope Ratio Assay

7.4 Evaluation of a Turbidimetric Antibiotic Assay by Angular Transformation of Response and Slope Ratio


Chapter 8 Choice of Method and Design

8.1 Choice of Method

8.2 General Considerations in Selection of Design

8.3 Plate Assay Designs

8.4 The Influence of Curvature in Parallel Line Assays

8.5 Choice of Design for Plate Assay

8.6 Tube Assays—General Considerations

8.7 Designs for Slope Ratio Assays

8.8 Influence of Curvature in Slope Ratio Assays

8.9 Choice of Design for Slope Ratio Assays

8.10 Tube Assays for Antibiotics


Chapter 9 Repeated Assays, Specifications, and Reports

9.1 Replication of Assays

9.2 Collaborative Assays

9.3 Combination of Replicate Potency Estimates

9.4 Combination of Replicate Potency Estimates—Simplified Methods

9.5 Specifications for Antibiotics

9.6 Official Standards—A Practical Approach


Appendix 1 Patterns for Small Plate Assays

Appendix 2 Calculations for Parallel Line Assays

Appendix 3 Potency Ratio, or F/E, Tables

Appendix 4 Proforma and Worked Example—Agar Diffusion Assay

Appendix 5 Sources of Reference Materials

A5.1 International Biological Standards and International Biological Reference Preparations

A5.2 British Biological Standards and Reference Preparations

A5.3 European Pharmacopeia Commission Reference Substances

A5.4 United States Pharmacopeia Reference Substances

A5.5 International Chemical Reference Substances

Appendix 6 The Dilution Of Reference Standards

Appendix 7 The Probit Transformation

Appendix 8 The Angular Transformation

Appendix 9 The t Distribution

Appendix 10 Variance Ratio Tables—The F Test

Appendix 11 The χ2 Distribution

Appendix 12 The Range/Mean Test

Appendix 13 Evidence That Quadratic Curvature is Without Influence in Balanced Parallel Line Assays



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© Academic Press 1977
28th January 1977
Academic Press
eBook ISBN:

About the Author

William Hewitt

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