Chapters authored
Pathogenicity Island in Salmonella
Considering a complex set of interplay with its host, Salmonella needs numerous genes for its full virulence. These genes responsible for invasion, survival, and extra intestinal spread are located on pathogenicity islands known as Salmonella pathogenicity islands (SPIs) that are thought to be acquired by horizontal gene transfer. A total of 17 SPIs (1–17) are recognized so far. The type III secretion system (T3SS) encoded by SPI-1 is considered as the most important virulence factor for Salmonella that delivers effector proteins necessary for invasion and production of enteritis. Among various SPIs, the role in virulence is well proven for SPI1 and SPI2 and further insight into the complex regulatory network of SPIs can contribute to drug investigation and prevention of infection.
Part of the book: Salmonella spp
Uropathogenic Escherichia coli
Urinary tract infections (UTIs) are among the most common infections encountered worldwide in clinical practice. Escherichia coli is by far the most frequent cause of infections responsible for nearly 80–90% of the infections. The strains of E. coli causing UTI are termed as uropathogenic E. coli. They vary from commensal strains as they have acquired virulence and resistant determinants through plasmids, bacteriophages, pathogenicity islands or DNA horizontal transfer of transposons which permits them to victoriously colonize the urinary tract and cause a broader spectrum of disease. For the fact, UPEC strains possess an abundance of both structural (as fimbriae, pili, flagella, capsule, lipopolysaccharide) and secreted (toxins, iron-acquisition systems, enzymes) virulence factors that play a crucial role in the pathogenesis. The pathogenesis of UPEC involves adherence, colonization, evading host defenses and damage to host tissue to achieve virulence. UTI is often treated empirically by broad-spectrum antibiotics in the absence of culture and susceptibility results. This over-use of antibiotics has resulted in the development of antibiotic resistance worldwide. Having a detailed understanding of the bacterium and its virulence factors can help us in developing new treatment options in presence of global antimicrobial resistance.
Part of the book: Enterobacteria