Preface

*Pseudomonas aeruginosa* is an opportunistic bacterium associated with a wide range of diseases that is commonly found in soil and water. It is also the leading cause of hospital-acquired infections and is associated with high morbidity and mortality among elderly and/or immunocompromised patients. Therefore, it represents a great challenge for health workers. As such, there are many benefits to be gained from studying these bacteria from biotechnological, industrial, environmental, and medical aspects. This book, Pseudomonas aeruginosa *– New Perspectives and Applications*, is an edited collection of reviewed and relevant research chapters on *P. aeruginosa*, which has significant implications for industry, medicine, and the environment. The book includes scientific contributions from various authors, edited by a group of experts in immunology and microbiology. Each contribution is a completely separate chapter in itself but is directly linked to the themes and aims of the book.

The book includes the following chapters:

Chapter 1: "The Role of *Pseudomonas aeruginosa* DsbA-1 in Bacterial Pathogenesis: Current Research and Future Prospects"

Chapter 2: "Searching for the Resistance Interactome of *Pseudomonas aeruginosa*"

Chapter 3: "*Pseudomonas aeruginosa*: The Alarming Pathogen of Hospital Acquired Infection"

Chapter 4: "Optimizing Shelf-life of *Pseudomonas fluorescens* after Freeze Drying"

Chapter 5: "The Pangenome of *Pseudomonas aeruginosa*"

Chapter 6: "*Pseudomonas aeruginosa* Represents a Main Cause of Hospital-Acquired Infections (HAI) and Multidrug Resistance (MDR)"

This book provides comprehensive information about this multifaceted microbe to scientists and specialists in this field for the benefit of humanity.

> **Osama Darwesh and Ibrahim Matter** Professor, Agricultural Microbiology Department, National Research Centre, Cairo, Egypt

**1**

**Chapter 1**

**Abstract**

Prospects

including peptidomimetics.

**1. Introduction**

*Sunil Kumar and Sonal Malhotra*

The Role of *Pseudomonas aeruginosa*

Disulfide bond isomerase proteins (Dsbs) have been extensively characterized in gram-negative bacteria. Recently research efforts is being placed on their biology in gram-positive species. Modern "omics" technologies, allowed assessment of the contribution of the Dsbs to bacterial pathogenesis. The author cloned and characterized the *dsbA* 1 protein from *Pseudomonas aeruginosa* in the late 1990s. The global proteome analysis demonstrated that the *dsbA* gene is under the direct regulatory control of the extracytoplasmic function (ECF) sigma factor AlgT(U) or sigma-22. This is unique to *P. aeruginosa*. Disruption of *dsbA* gene results in pleiotropic phenotype: defect in assembly of cysteine disulfide bond containing proteins-as shown in many others. Recently, omics-based approaches identified expression changes in *dsbA* gene under different physiological states of bacterial pathogens-primarily in free-living, biofilm state, or under infectious disease conditions. Involvement of *dsbA* function in biofilm formation was shown using *dsbA* gene disruption mutants. This chapter documents past and current findings and concludes with future trends in research on Dsbs

**Keywords:** bacterial pathogenesis, disulfide isomerase, OMICS technology,

microarrays, metatranscriptomics, metabolomics, animal models of disease

proteomics, extracytoplasmic function (ECF) sigma factors, thiol status, Sigma factors,

This chapter examines the biology of disulfide bond isomerase (Dsb) proteins and how these proteins are involved in assembly of virulence determinants in the bacterial cell [1]. We first examine the function of these proteins within the cell. DsbAs are proteins that facilitate the formation of the disulfide bond. This bond exists between two cysteine amino acid residues. The "R" group in this amino acid contains thiol or "SH" group at its end. The thiol group needs to be oxidized and DsbA or DsbA-like proteins aid in this. Slow oxidation of the thiol group is possible (**Figure 1**). The disulfide bond can be intrachain-within one polypeptide or alternatively between two

DsbA-1 in Bacterial Pathogenesis:

Current Research and Future
