Preface

*Escherichia coli* is one of the best known and most extensively studied microorganisms that has been proven to be an important microbe. It is famous for its contributions to unraveling fundamental biological processes in genetics, molecular biology, biochemistry, physiology, ecology, and evolution. In addition, it is known for its mobile genetic elements that can carry many genes involved in either bacterial virulence or resistance to antibiotics, even multi-drug resistance, supplementary metabolic pathways, and colicin production. *E. coli* plays an important role not only in the host, whether as a mutualistic bacterium, an intestinal pathogen, or an extraintestinal pathogen, but also in basic and applied research. Moreover, *E. coli* is widely used in recombinant DNA technology and biotechnology.

This book offers insights into all the different aspects of *E. coli*. It is organized into four sections.

The first section introduces the topic. Chapter 1 provides a general overview of the main characteristics of *E. coli*. Chapter 2 presents the knowledge landscape of *E. coli* and highlights the scientific topics that have been the focus of research over the last four decades, as revealed by scientometric analysis. Chapter 3 highlights the largest, most complex, and best-characterized bacterial network induced by DNA damage, known as the SOS response, and shows its broader importance beyond DNA damage repair. Chapter 4 introduces the modern molecular diagnostic platforms for specific detection of *E. coli*.

The second section discusses *E. coli* pathogenicity. Chapter 5 reviews the biology and evolutionary dynamics of diarrheagenic *E. coli*. Chapter 6 describes the "famous" intestinal pathogen O157:H7 *E. coli* and its impact on human health. Chapter 7 presents the virulence factors of uropathogenic *E. coli*. Chapter 8 discusses preharvest factors affecting the microbial safety of leafy vegetables and management strategies for effective on-farm food safety.

The third section deals with antimicrobial resistance and possible new ways to combat antibiotic resistance, since there has been an increase in antimicrobial-resistant strains of *E. coli* posing risks to human health. Chapter 9 provides a general overview of antimicrobial resistance in *E. coli*. Chapter 10 describes the mechanisms of antimicrobial resistance in *E. coli*. Chapter 11 introduces potential new antimicrobial agents, such as antimicrobial peptides. Chapter 12 discusses new vaccines, probiotics/postbiotics/ synbiotics, and the CRISPR-Cas system. Chapter 13 discusses antimicrobial plant extracts.

The final and fourth section examines useful *E. coli*. Chapter 14 discusses *E. coli*  that can be used to improve health and disease management, the so-called probiotic *E. coli*, whereas Chapter 15 focuses on *E. coli* that can be used in biotechnology to produce useful products, such as *E. coli-*based DNA amplification-expression technology for automatic assembly of concatemeric open reading frames (ORFs) and proteins.

Overall, this book presents old and new insights into all aspects of *E. coli* and I hope it will help readers recognize the importance of this microorganism.

My sincere thanks to all the contributing authors and to the staff at IntechOpen who made the publication of this book possible.

> **Dr. Marjanca Starčič Erjavec** Professor, Biotechnical Faculty, Department of Microbiology, University of Ljubljana, Ljubljana, Slovenia

Section 1

Introduction to *Escherichia coli*
