Preface

With this eighth edition, Sherris Medical Microbiology will enter its fifth decade as Sherris & Ryan’s Medical Microbiology. We are pleased to welcome new authors Julie M. Steinbrink and Gayatri Vedantam from Duke University and the University of Arizona. John Sherris, the founding editor, continues to act as an inspiration to all of us (see Dedication).

The goal of Sherris & Ryan’s Medical Microbiology remains unchanged from that of the first edition (1984). This book is intended to be the primary text for students of medicine and medical science who are encountering microbiology and infectious diseases for the first time. Part I opens with a chapter that explains the nature of infection and the infectious agents at the level of a general reader. The following four chapters give more detail on the immunologic, diagnostic, and epidemiologic nature of infection with minimal detail about the agents themselves. Parts II through V form the core of the text with chapters on the major viral, bacterial, fungal, and parasitic diseases, and each begins with its own chapters on basic biology, pathogenesis, and antimicrobial agents.

In the specific organism/disease chapters, the same presentation sequence is maintained throughout the book. First, features of the Organism (structure, metabolism, genetics, etc.) are described; then mechanisms of the Disease (epidemiology, pathogenesis, immunity) the organism causes are explained; the sequence concludes with the Clinical Aspects (manifestations, diagnosis, treatment, prevention) of these diseases. A clinical Case Study followed by questions in USMLE format concludes each of these chapters. In Sherris & Ryan’s Medical Microbiology, the emphasis is on the text narrative, which is designed to be read comprehensively, not as a reference work. Considerable effort has been made to supplement this text with other learning aids such as the above-mentioned cases and questions as well as tables, photographs, and illustrations.

This edition continues a number of new study aids first seen in the seventh edition. These were the product of a Student Advisory Group conceived and led by Laura Bricklin, MD then a second-year medical student at the University of Arizona College of Medicine. They include a boxed narrative OVERVIEW opening each disease-oriented chapter or major section, highlighted MARGINAL NOTES judged to be “high yield” for USMLE Step 1 preparation, and bulleted lists of KEY CONCLUSIONS at the end of major sections. A THINK → APPLY feature randomly inserts thought-provoking questions into the body of the text, which are answered at the bottom of the page. These new features are explained in detail and illustrated on pages iv and v. Practice Questions in USMLE format are also included. In the online version of this book the case-based, and other USMLE type questions are presented independent of the narrative text.

For any textbook, dealing with the onslaught of new information is a major challenge. In this edition, much new material has been included, but to keep the student from being overwhelmed, older or less important information has been deleted to keep the size of this book no larger than of the seventh edition. As a rule of thumb, material on classic microbial structures, toxins, and the like in the Organism section has been trimmed unless its role is clearly explained in the Disease section. At the same time, we have tried not to eliminate detail to the point of becoming synoptic and uninteresting. Genetics is one of the greatest challenges in this regard. Without doubt this is where major progress is being made in understanding infectious diseases, but a coherent discussion may require using the names and abbreviations of genes, their products, and multiple regulators to tell the complete story. Whenever possible we have tried to tell the story without all the code language. We have also tried to fully describe the major genetic mechanisms in general chapters and then refer to them again when that mechanism is deployed by a pathogen. For example, Neisseria gonorrhoeae is used to explain the genetic mechanisms for antigenic variation in a general chapter on bacterial pathogenesis (Chapter 22), but how it influences its disease, gonorrhea, is taken up with its genus Neisseria (Chapter 30).

A saving grace is that our topic is important, dynamic, and fascinating—not just to us but to the public at large. Newspapers, radio, television, and now social media reports of infectious diseases are now filled daily with details of the Covid-19 pandemic. Resistance to antimicrobial agents and the havoc created by antivaccine movements remain regular topics on the evening news. It is not all bad news. We sense a new optimism that deeper scientific understanding of worldwide scourges like Covid-19, HIV/AIDS, tuberculosis, and malaria will lead to their control. We are hopeful that the basis for understanding these changes is clearly laid out in the pages of this book.