Manual for the Determination of the Clinical Role of Anaerobic Microbiology

Lorraine S. Gall

• Publisher: CRC Press
• Year: 2018
• Print ISBN: 9781315895178
• eBook ISBN: 9781351091176
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Biology
• Index: Biological Sciences

Clinicians are becoming more aware and concerned about anaerobic bacterial infections as more is learned about these anaerobic bacteria. An attempt will be made in this manual to provide the information to perform an evaluation for each individual laboratory concerning the possible addition of the routine culture of anaerobe to their laboratory analysis of body fluids and tissue specimens.

Chapter 1

The Role of Anaerobic Bacteriology in the Clinical Laboratory

I. Introduction

Clinicians are becoming more aware and concerned about anaerobic bacterial infections as more is learned about these anaerobic bacteria. As a result, many clinical bacteriologists and pathologists are being asked to decide whether to add the routine culture of anaerobes to their laboratory analysis of body fluids and tissue specimens, and if so, in what depth the examination should be conducted. This is not a simple decision and must be based on a consideration of all the aspects of anaerobic culturing. An overall evaluation can be made by drawing up a balance sheet, weighted with respect to the priority of each aspect on which an informed decision can be based. An attempt will be made in this manual to provide the information to perform this evaluation.

II. Factors Entering Decision for an Anaerobic Bacteriology Laboratory

What are some of the factors which should enter into such a decision?

A. Technical Aspects

First there are the technical aspects. A practical, working definition of an anaerobe must be arrived at, followed by a discussion of several characteristics of anaerobes and the peculiarities of their culture. The distinction must then be made as to which anaerobes are clinically important and which are normal flora at that body site. Once the clinically important anaerobes have been selected, the requirements for isolation and identification of these anaerobes can be compiled. The available techniques for collection, transport, isolation, identification, and antibiotic susceptibility testing can be tabulated for easy comparison. Then an evaluation can be made that will aid in the selection of the techniques best suited for the individual laboratory under consideration.

After the appropriate techniques have been selected, the analytical scheme for the examination of the cultures can be explored. Decisions will be needed on an individual basis for many of the clinically important anaerobes, especially those that are resistant to antibiotics normally used in the treatment of patients with anaerobic infections. The sum total of these individual decisions will indicate the extent of the anaerobic culturing necessary for each laboratory situation.

B. Practical Aspects

There are several practical factors related to anaerobic culturing which should be taken into account. Some of these, such as time spent on the analysis, will be influenced substantially by the techniques chosen and the intended extent of examination of the anaerobic specimens, but the performance of any anaerobic culturing at all with entail certain of these factors. For example, manpower, both quality and quantity, is of prime importance in establishing an anaerobic capability, as is laboratory space and special anaerobic equipment. Also, the cost of the laboratory both as a capital investment and as a continuing outlay must be calculated realistically.

C. Personnel Aspects

Of equal importance to a consideration of the technical side of the question is the attitude of the attending physician about anaerobic infections. His attitude is of vital importance in the decision relating to the setting up of an anaerobic laboratory for two reasons. First, the doctor is an essential link in the utilization of the information obtained from anaerobic culturing. Obviously there is little payoff if the results are not used by the physician, either because of lack of interest or ignorance of how to apply this information to patient treatment. The second reason that the interested physicians are important is related to the collection of the anaerobic specimen. For accurate and relevant results, specimens intended for anaerobic culturing often are collected using special techniques that involve surgical or semisurgical procedures, for the performance of which a physician is the most qualified person. The cooperation of the physician is therefore doubly important—in the proper collection of the specimen and in the informed utilization of the results in the treatment of the patient.

The question to be answered is straightforward. Are the attending physicians that use your laboratory sufficiently interested to ensure proper specimen collection and utilization of the cultural results? If not at the present time, can they be trained and if so, what is the best method of training? Similar thought should be applied to the laboratory staff. Will their interest be keen enough to ensure their conscientious and intelligent performance of the anaerobic analysis?

D. Future Aspects

One final aspect which enters into the decision is the future developments which may reasonably be expected in the field of anaerobic culturing. Will they stay at the same level or expand? Will techniques improve? Will the present gaps in our information be filled in? Will the nomenclature stabilize? Will automated instrument systems include an anaerobic capability? Consideration of these questions is necessary as part of an informed decision on starting an anaerobic laboratory.

E. Evaluation Process

After all the up-to-date information on each of these aspects has been assembled, and where possible tabulated, priorities must be set and at least a mental weighting scheme employed so that the most important factors with respect to your laboratory will receive the most attention. Careful consideration of all of the aspects of anaerobic culturing should allow a satisfactory, informed decision to be made concerning the establishment of an anaerobic capability in your laboratory.

III. Subject Matter of Manual

The material contained in this manual is not intended to offer an inclusive review of any of the aspects of anaerobic bacteriology, but rather to select and organize the available information needed to give a practical picture of what is involved in establishing, maintaining, and/or upgrading a functional anaerobic microbiological laboratory at the level best suited to the individual situation. Thus, emphasis is placed on discussing the alternate techniques available for each step of the analysis in sufficient detail to compare the complexity, specialized equipment, laboratory space requirements, and cost of start-up and continuing expenditures required by each of the several alternative choices. In an attempt to do this, the topics covered in this manual will include separate chapters discussing the four important steps in anaerobic microbiological analysis—collection and transport of the specimen, primary culture and isolation of the clinically important anaerobes, and identification and antibiotic susceptibility; comments on the aspects to be considered in evaluating these techniques will also be included. There is also a brief look at promising future developments which may soon become candidate procedures for inclusion in the laboratory and thus need to be considered when planning the laboratory.

No attempt will be made to discuss which anaerobes may appear in certain specimens except in a very general way, and there will be no discussion of the treatment of the patient, as these topics do not relate directly to planning the laboratory and are the subject of a number of excellent publications.

IV. Literature Sources

The material in this manual will be drawn heavily from review articles, books, and laboratory manuals of several recognized groups of experts in the field of anaerobic microbiology plus appropriate papers on specialized aspects discussed in the various chapters. No attempt will be made to judge the relative merits of the work of these groups, other than to state the facts needed for comparison of the techniques, since the needs of each laboratory are individual and what may be best for one laboratory is not suitable for another. Also there is no intention to suggest that the experts active in this field are limited to those cited in this manual, as this is not intended as a comprehensive review, but as a basis for setting up a practical laboratory. Thus for the sake of keeping the manual simple and as useful as possible, an attempt has been made to reduce confusion in this controversial field by discussing thoroughly the methods used with greatest frequency and hence offering the most data on which to base comparisons. One of the last chapters deals with promising new developments which may prove to become the methods favored in the future.

Several recent reviews and laboratory manuals will be listed below as suggested background reading to get an overview of the laboratory practices and their background in anaerobic microbiology.

1. Dowell, V. R., Jr, and Hawkins, T. M., Laboratory Methods in Anaerobic Bacteriology, Publ. No. 78-8272, Center for Disease Control, Public Health Service, U.S. Department of Health, Education and Welfare, Atlanta, 1977.

2. Holdeman, L. V., Cato, E. P., and Moore, W. E. C., Anaerobe Laboratory Manual, 4th ed., Anaerobe Laboratory, Blacksburg, Va., 1977.

3. Sutter, V. L., Citron, D. M., and Finegold, S. M., Wadsworth Anaerobic Bacteriology Manual, 3rd ed., C.V. Mosby, St. Louis, 1980.

4. Smith, L. D. S., in The Pathogenic Anaerobic Bacteria, 2nd ed., Balow, A., Ed., Charles C Thomas, Springfield, Ill., 1975, chap. 1 and 2.

5. Balows, A., Dehaan, R. M., Dowell, V. R., Jr., and Guze, L. B., Anaerobic Bacteria: Role in Disease, Section I, Charles C Thomas, Springfield, Ill., 1974.

6. Finegold, S. M., Shepherd, W. E., and Spaulding, E. H., Practical Anaerobic Bacteriology, Cumitech 5, American Society for Microbiology, Washington, D.C., 1977.

7. Finegold, S. M. and Sutter, V. L., Diagnosis and Management of Anaerobic Infections, Scientific Exhibit, Wadsworth Hospital Center, Veterans Administration and UCLA School of Medicine, Los Angeles, 1976.

8. Finegold, S. M., Anaerobic Bacteria in Human Disease, Academic Press, New York, 1977, chap. 1–3.

9. Finegold, S. M., Sutter, V. L., Cato, E.P., and Holdeman, L. V., Anaerobic bacteria, in Rapid Diagnostic Methods in Microbiology, Graber, C.D., Ed., Williams & Wilkins, Baltimore, 1970, chap 6.

10. Morello, J. A., and Graves, M. H., Clinical anaerobic bacteriology, Lab. Manage., 15, 4, 1977.

11. Tally, F. P., Bartlett, J. G., and Gorbach, S. L., Practical Guide to Anaerobic Bacteriology, Lab. Med., 8, 26, 1978.

12. Willis, A. T., Anaerobic Bacteriology—Clinical and Laboratory Practice, 3rd ed., Butterworths, London, 1977.

Chapter 2

Clinically Important Anaerobic Bacteria

I. Introduction

The human body harbors a vast anaerobic microflora, both with regard to total numbers of anaerobes and various types of organisms. Many of these anaerobes are considered to be normal flora, but certain anaerobes are frequently associated with pathological condition and are designated to be clinically important anaerobes.

Before the clinically important anaerobes are discussed, there is certain background material relating to anaerobic bacteria which needs to be considered, such as the classification of a bacterium as an anaerobe, including a practical definition of an anaerobe, the special characteristics of anaerobes and their impact on cultural procedures, the occurrence of anaerobes in relation to a diseased body area, and the establishment of their role in disease.

II. What is an Anaerobe?

A. Cause of Anaerobiosis

The precise answer to the question of what constitutes an anaerobic bacterium is still under study. There is general agreement that exposure to oxygen exerts a deleterious effect, either directly or indirectly, on bacteria considered to be anaerobes, but the exact cause of this is the subject of conflicting theories. Most of these theories center around the lack of certain enzyme systems, such as catalase or superoxide dismutase, which are involved in the metabolism of oxygen. The confusion is compounded by the fact that even though certain bacteria possess one or the other of these enzyme systems, they still are advers...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Contents
• Preface
• The Authors
• Acknowledgment
• Dedication
• Chapter 1 The Role of Anaerobic Bacteriology in the Clinical Laboratory
• Chapter 2 Clinically Important Anaerobic Bacteria
• Chapter 3 Requirements for Anaerobic Microbiological Analysis
• Chapter 4 Collection and Transport of Specimens for Anaerobic Culturing
• chapter 5 Commonly used Techniques for the Primary Culturing and Isolation of Clinically Important Anaerobic Bacteria
• chapter 6 Methods of Identification of Clinically Important Anaerobes
• chapter 7 Determination of Antibiotic Susceptibility of Clinically Important Anaerobes
• chapter 8 Personnel Considerations
• chapter 9 Future Developments in Anaerobic Microbiology
• chapter 10 Overall Evaluation as a Basis for Decision on the role of Anaerobic Microbiology in your Clinical Laboratory
• Appendix I
• Index