Pseudomonads and Their Rapid Detection

Description of Pseudomonad Organisms

Pseudomonas bacteria (Pseudomonads) encompass gram negative, motile, non-fermenting rods. This genus is ubiquitous in nature and these organisms can impact a number of environments and patient populations. The Pseudomonads may be found in soil, on plant material, in water, and can be isolated from various tissues and body fluids from mammals. In human health, some of these organisms, primarily Pseudomonas aeruginosa, can be an opportunist pathogen and cause serious health problems. If allowed to reach unsafe levels, this organism may cause several health problems including skin rash and other skin infections, ear infection, urinary tract infection, and in rare instances, pneumonia. Other Pseudomonads, for example, P. stutzeri can be isolated from wounds but are generally not associated with human disease. Many Pseudomonads found in the soil can damage plant materials by causing spoilage.

Who tests for Pseudomonas and why?

Water Testing: Pseudomonas aeruginosa is a bacterium commonly found in purified water systems. Pseudomonas grows in water. It thrives at warm temperatures, which is why it is so often associated with spas. It can also grow in purified water systems.

Pharmaceutical and Cosmetic Products: Analysis of FDA product recall data for 134 non-sterile pharmaceutical products from 1998 to September 2006 demonstrated that 48% of recalls were due to contamination by either Burkholderia cepacia, or Pseudomonas spp (Jimenez L. 2007). In cosmetic products, P. aeruginosa was recovered from contaminated mascara material and was identified as the agent responsible for corneal ulcers in the 1970s (Ortho 2009). Pseudomonads can survive and grow in DI water—Contaminated DI water may be the source of microbial contamination if it is used for the final rinse of equipment that has been cleaned and sanitized, and it may be the source of contamination for finished products in these industries.

Dairy and Food: The predominant microorganisms limiting the shelf life of processed fluid milk at 4°C are Pseudomonas spp. these species are able to grow to high numbers during refrigerated storage. Pseudomonas species accounted for79% of the psychotropic isolates that spoiled pasteurized milk (Dogan and Boor 2003). Important characteristics of Pseudomonads include their abilities to grow at low temperatures (3–7?C) and to hydrolyze and use large molecules of proteins and lipids for growth.

Biolumix Offers Two Options for Detecting Pseudomonads

For certain industries it is important to detect Pseudomonas aeruginosa, while for others it is important to detect all Pseudomonas spp, including the closely related Burkholderia cepacia. As a result BioLumix offers two different types of vials: the PSE vial for the detection of P. aeruginosa; and the PSB vial for the detection of all strains of Pseudomonas and for B. cepacia.

Detection of Pseudomonas aeruginosa (PSE Vial)

For the Pharma (OTC), Cosmetic and Nutraceutical Industries the primary cause for concern is the absence or presence of Pseudomonas aeruginosa. P. aeruginosa is common and is able to become an opportunistic pathogen in people and may cause severe disease (Hugh and Gilardi 1974). The ability to detect P. aeruginosa is critical in the non sterile Pharmaceutical products, Cosmetic and Nutraceutical Industries to ensure the product material is safe. BioLumix offers a highly selective media in the form of a test vial (PSE) that primarily only allows for the growth of Pseudomonas aeruginosa organisms. Confirmation of the presence of this organism is accomplished using the simple Oxidase reaction on vial contents. The test sample is merely enriched in TSB (Tryptic Soy Broth) per USP instructions and then tested directly in the BioLumix PSE vial. Other common Pseudomonads and closely related organisms, including B. cepacia and P putida, as examples, are excluded from growth due to the use of antibiotic supplements in the BioLumix PSE vial. P. aeruginosa is typically more antibiotic resistant than other Pseudomonas organisms (Blazevic, DL et al 1973). Figure 1 illustrates the growth curve of Pseudomonas aeruginosa ATCC 9027 in the BioLumix PSE vial.

KEY:Dark Blue Curve- P. aeruginosa Green Curve- Negative Control

Detection of other Pseudomonads (PSB Vial)

For many industries including the dairy industry and manufacturers using water, there is a need to test for all Pseudomonads as they impact these industries economically. Other Pseudomonads may include P. fluorescens, P. putida, and P. stutzeri. Burkholderia cepacia, can also be detected using the BioLumix PSE-B vial. Specific to the use of water in manufacturing: Pseudomonas bacteria can be found naturally in the ground and within drinking water sources such as aquifers. Contamination of either dairy products or water systems by Pseudomonads is something to avoid and early detection of goods using a rapid microbiological detection system such as the BioLumix Instrument System, would offer an advantage to the manufacturer. Figure 2 illustrates the growth of many types of Pseudomonads and Burkholderia cepacia in the BioLumix PSE-B vial.

KEY: Dark Blue Curve- B. cepacia; Green Curve -P aeruginosa; Light Blue Curve – P. putida; and Red Curve– P. fluorescens growth


Blazevic, DJ, Koecke, M.H., and Mastsen J.M. (1973). Incidence and identification of Pseudomonas fluorescens and Pseudomonas putida in the clinical laboratory. Applied Microbiology 25: (1)

Dogan, B. and Boor, K J. (2003). Genetic diversity and spoilage potentials among Pseudomonas ssp. isolated from fluid milk products and dairy processing plants. Appl. Microbiol.,69: 130-138.

Hugh, R. and Gilardi, G. (1974) In “Manual of Clinical Microbiology” Edited by Spaulding, Lennette, Spaulding and Truant. Chapter 23 Pseudomonas.

Jimenez L.(2007). Microbial diversity in pharmaceutical product recalls and environments. Review. PDA J Pharm Sci Technol. 2007 Sep-Oct;61(5):383-99.

Ortho D. (2009). Insight into Cosmetic Microbiology, Chapter 8 263-267

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