Cultivation of Pseudomonas

Consistent Quality Culture Media

For the enrichment, isolation and enumeration of Pseudomonas, Merck provides high quality culture media to be used for quality control in the food and beverages industries. These media are available in a variety of formulations as dehydrated culture media in the form of granules. The granulated format enhances both convenience and safety: It causes significantly less dust development than when using powdered media. As a consequence it leads to less inhalation of hazardous media components that may lead to allergic responses and minimizes contamination of the work environment.

Like all Merck media, our culture media for Pseudomonas meet the most stringent industry performance standards as described in ISO 11133 and are quality controlled according to strict standards. This guarantees the quality and batch-to-batch consistency of our products.

The Diversity of Pseudomonas

Pseudomonas is a genus of the family Pseudomonadaceae that contains about 180 species. These gram-negative aerobic gammaproteobacteria show a wide range of metabolic diversity and occupy a wide range of niches. Pseudomonads are rod shaped and have one or more polar flagella used for motility. They do not form spores and are catalase and oxidase positive. Production of pyoverdine, a fluorescent yellow-green siderophore, under iron-restricted conditions as well as of other siderophores is also associated with Pseudomonas.

Although most pseudomonads are strict aerobes, exceptions have been found in biofilms. A significant quantity of such cells is able to produce exopolysaccharides which are associated with biofilm formation and the colonization of surfaces. Biofilms tend to be difficult to remove from food preparation surfaces. Secreted exopolysaccharides also make it hard for mammalian white blood cells to phagocytose pseudomonads. With the additional ability to metabolize a variety of nutrients, Pseudomonas can survive in a wide range of inhospitable places.

P. aeruginosa, P. oryzihabitans and P. plecoglossicida are among the infectious species. P. aeruginosa is the second most common cause of infection among hospitalized patients. It flourishes in health care environments and is therefore a particular problem. A multitude of Pseudomonas species are able to act as plant pathogens, of which P. syringae is the most widespread and studied. Since the mid-1980s, some species, including Pseudomonas fluorescens, have been used as biocontrol agents. To prevent crop pathogens from growing and establishing themselves, such pseudomonads were applied to cereal seeds or directly to soils.