Infectious diseases have existed longer than us, as long as us, or are relatively newer than us. It may be the case that a disease has existed for many, many years but has only recently begun affecting humans. At the turn of the century the number of deaths caused by infections in the United States had been falling steadily but since the '80s has seen an increase. In the past 30 years alone 37 new pathogens have been identified as human disease threats and 12% of known human pathogens have been classified as either emerging or remerging. Whatever the story, there is currently a "war" on infectious diseases. This war is simply the systematic search for the microbial "cause" of each disease, followed by the development of antimicrobial therapies. The "war" on infectious diseases, however, must be revisited in order to develop a more realistic and detailed picture of the dynamic interactions among and between host organisms and their diverse populations of microbes. Only a fraction of these microbes are pathogens. Thus, in order to explore the crafting of a new metaphor for host-microbe relationships, and to consider how such a new perspective might inform and prioritize biomedical research, the Forum on Microbial Threats of the Institute of Medicine (IOM) convened the workshop, Ending the War Metaphor: The Changing Agenda for Unraveling the Host-Microbe Relationship on March 16-17, 2005. Workshop participants examined knowledge and approaches to learning about the bacterial inhabitants of the human gut, the best known host-microbe system, as well as findings from studies of microbial communities associated with other mammals, fish, plants, soil, and insects. The perspective adopted by this workshop is one that recognizes the breadth and diversity of host-microbe relationships beyond those relative few that result in overt disease. Included in this summary are the reports and papers of individuals participating in the Forum as well as the views of the editors.

In light of the rapidity increasing incidence rate of bacterial and fungal infections with multi-resistant pathogens, the metabolic changes associated with host-pathogen interactions offer one of the most promising starting points for developing novel antibiotics. . Part one of this comprehensive guide describes the metabolic adaptation of pathogenic microbes in humans, while part two points to routes for the development of novel antibiotics. This is volume six of the book series on drug discovery in infectious diseases by Paul Selzer.

The use of microbial plant protection products is growing and their importance will strongly increase due to political and public pressure. World population is growing and the amount of food needed by 2050 will be double of what is produced now whereas the area of agricultural land is decreasing. We must increase crop yield in a sustainable way. Chemical plant growth promoters must be replaced by microbiological products. Also here, the use of microbial products is growing and their importance will strongly increase. A growing area of agricultural land is salinated. Global warming will increase this process. Plants growth is inhibited by salt or even made impossible and farmers tend to disuse the most salinated lands. Microbes have been very successfully used to alleviate salt stress of plants. Chemical pollution of land can make plant growth difficult and crops grown are often polluted and not suitable for consumption. Microbes have been used to degrade these chemical pollutants.

Host-Microbe Interactions, the latest volume in the Progress in Molecular Biology series, provides a forum for the discussion of new discoveries, approaches, and ideas in molecular biology. It contains contributions from leaders in their respective fields, along with abundant references. This volume is dedicated to the subject of host-microbe interactions. Provides the latest research on host-microbe interactions, including new discoveries, approaches, and ideas Contains contributions from leading authorities on topics relating to molecular biology Informs and updates on all the latest developments in the field

This Research Topic presents knowledge on transition metal metabolism in various infections from the dual perspective of offender and defender. 1) Host Nutritional Immunity: depriving or poisoning. To date, the implication of divalent metals have been described in two different immune strategies that aim to fight microbial invaders. One consists in depriving microbes of essential divalent metals whereas the other aims at overloading invaders with toxic concentrations of metal. The contributions in this section present, in different situations, various aspects of this metal economy at the host-microbe interface. Two papers deal with metal homeostasis as hosts interact with bacteria. Diaz-Ochoa et al. (2014) review immunological mechanisms to sequester Fe, Mn and Zn in the inflamed gut and strategies of commensals and pathogens to evade mucosal defenses and obtain such nutrients. Lisher & Giedroc (2013) detail chemical and structural mechanisms to capture Mn, an antioxidant used by pathogens to adapt to human hosts, and the impact of Fe and Zn on Mn bioavailability during infections. The most coveted metal, iron is key to nutritional immunity and microbial virulence. Using amoeba as model phagocyte, Bozzaro et al. (2013) present the tug of war between a bacterial predator, sequestering intracellular iron to resist invasion, and pathogens which elude such defense mechanisms. On mammalian defense against intracellular bacteria and protozoan parasites, Silva-Gomes et al. (2013) outline divergent approaches: iron-withholding to prevent microbial replication or iron-based oxidative injury to kill invaders. Host may also target invaders with toxic doses of Cu and Zn, normally kept at low concentrations. Neyrolles et al. (2013) present an opinion article on bacterial Zn and Cu poisoning in the context of Mycobacterium tuberculosis infection. Chaturvedi & Henderson (2014) summarize the specific properties of copper and its toxic effect on bacteria cells. Argüello et al. (2013) review how bacteria integrate homeostatic mechanisms to avoid Cu toxicity by sensing and regulating ion chelation, chaperoning and membrane transport. 2) Microbial adaptation to host defenses: metallo-transporters or exporters. To overcome host resistance to infection, numerous mechanisms have been selected through the course of microbial evolution, in particular transporters that can feed the bacteria even at low metal concentration or, on the contrary, metallo-exporters that can expel metals outside the cell to avoid toxic accumulation. The articles in this section describe the microbial transport arsenal, and its regulation, which play major roles to influence metal economy at the host-microbe interface. Bacterial and fungal strategies to acquire Fe is the subject of four contributions. Liu & Biville (2013) discuss erythrocyte parasitism by Bartonella, transmitted by arthropod vectors and relying principally on heme capture and oxidative stress defense to cause persistent infections. Runyen-Janecky (2013) highlights some of the recent findings on heme iron acquisition system and the regulation of their expression in Gram-negative pathogens. Cornelis & Dingemans (2013) recap how Pseudomonas adapts means of iron capture to the type of infection it establishes, acute or chronic. Caza & Kronstad (2013) contrast strategies of virulent bacteria and fungi to subvert host immunity and steal iron from hemoglobin, heme, transferrin and lactoferrin or elemental iron using specialized uptake systems and siderophores. Five papers deal with microbial homeostasis of other metals Mn, Ni and Zn. Honsa et al. (2013) review the roles of importers and exporters of Mn, Fe, Zn and Cu in Streptococcus pneumoniae gene regulation and tissue-specific pathogenesis. Guilhen et al (2013) focus on families of exporters and the role of metal efflux in the evolution of Neisseria meningitidis virulence and naso-pharyngeal c