Effect of Iron Depletion on Protein Profiles of Bilophila wadsworthia

Pathogenicity of microorganisms is a multifactorial phenomenon. Host environment plays a role in the development of the infectious process. The presence of key nutrients, such as iron, may be important for the expression of virulence factors. Iron is an essential component of a wide variety of biochemical processes in microorganisms, and its availability is of major importance in bacterial pathogenesis. In response to a low level of available iron in vivo, the creation of high-affinity iron-uptake systems and of a number of iron-regulated membrane proteins is induced. Although relationships between iron and virulence factors of aerobes have been better studied, a few such studies have been carried out with regard to anaerobes (mainly Bacteroides fragilis). As discussed by Duerden, there is as yet no clear understanding of many of the virulence factors of anaerobes. Little is known about the mechanisms of iron uptake used by anaerobic bacteria, and nothing about those of Bilophila wadsworthia. The purpose of this work was to study the properties of this recently recognized anaerobe in relation to iron metabolism. B. wadsworthia is an anaerobic, gram-negative, asaccharolytic, bile-resistant, and strongly catalase-positive bacillus. This bacterium was first isolated from patients with gangrenous and perforative appendicitis. This study sought to determine whether B. wadsworthia expressed iron-regulated outer-membrane proteins (OMPs) in an iron-depleted environment and whether these proteins were immunogenic.