Although the vast majority of bacteria are harmless or beneficial, quite a few bacteria are pathogenic. Pathogenic bacteria are only pathogenic under certain conditions, such as a wound that allows for entry into the blood, or a decrease in immune function. In this book, the authors present current research in the study of the virulence mechanisms, diagnosis and management of bacterial pathogens. Topics discussed include Pseudomonas aeruginosa (P aeruginosa) in our environment; phage therapy in the treatment of bacterial infections; P mirabilis virulence factor associated with urinary tract infections; efflux pumps for the multi-drug resistant phenotypes of bacterial pathogens; and the role of HtrA as a chaperone and protease in bacterial pathogenesis.