If your manufacturing processes utilize purified water or highly purified water, Ralstonia pickettii should be on your list of microorganisms to control. In fact, it has become a microorganism of concern to sterile drug manufacturers because it is capable of passing through traditional 0.2-µm sterilizing-grade filters.

Additionally, R. pickettii has become recognized as a nosocomial pathogen particularly associated with immunosuppressed patients.

Where has R. pickettii been found?

1. Pharmaceutical solutions including intravenous medications, saline, and chlorhexidine skin cleansing solutions.
2. Municipal drinking water supplies, bottled water, dental water supplies, and hospital water supplies
3. Biofilms in plastic industrial water piping

Description:

Gram-negative, motile, non-spore-forming rods. Cells are diminutive (0.5-0.6 X 1.5-3.0 µm) and possess one polar flagella.

Conditions for Growth:

R. pickettii grows aerobically. Its optimal temperature range for growth is 30 to 37°C but it can also grow at 41°C. The species will not grow at 5°C.

Colony Morphology:  

Most strains grow well on Tryptic Soy Agar (TSA) and Nutrient Agar. Colonies are beige-colored, domed, smooth and glistening on TSA.

Habitat:

R. pickettii is found worldwide in soil and water.

Pathogenicity:

R. pickettii has been associated with nosocomial infections. It may cause bacteremia, meningitis, endocarditis, and osteomyelitis in debilitated and immunosuppressed individuals.

Contamination Potential: 

R. pickettii is a common contaminant in purified water systems. It has been isolated from biofilms in industrial plastic water piping and from industrial high-purity water.  It has also been found in intravenous medications, saline, respiratory therapy solutions, and chlorhexidine skin cleansing solutions. R. pickettii has been shown to penetrate a 0.2 micron rated membrane.

Family:

Burkholderiaceae. Genus: Ralstonia. Other members of the genus include Ralstonia metallidurans, a metal-resistant microbe which was isolated from wastewater at a zinc factory, and Ralstonia solanacearum, a plant pathogen which causes wilt in tomato, potato, tobacco and banana plants.

References: 

Clontz, L. (2009). Microbial Life and Ecology. In Microbial Limit and Bioburden Tests: Validation Approaches and Global Requirements (2nd ed. pp. 1-34). Boca Raton, Florida: CRC Press.

LiPuma, J., Currie, B., Peacock, S., & Vandamme, P. (2011). Burkholderia, Stenotrophomonas, Ralstonia, Cupriavidus, Pandoraea, Brevundimonas, Comamonas, Delftia, and Acidovorax. In Manual of Clinical Microbiology (10th ed., Vol. 1, pp. 692-713). Washington, DC: ASM Press.

Ryan, M., Tony, P., & Adley, C.  (2011), Genotypic and phenotypic diversity of Ralstonia pickettii and Ralstonia insidiosa isolates from clinical and environmental sources including High-purity Water. Diversity in Ralstonia pickettii. BMC Microbiology, published online, 11:194  

Sundaram, S., Auriemma, M., Howard Jr, G., Brandwein, H., & Leo, F. (1999).  Application of membrane filtration for removal of diminutive bioburden organisms in pharmaceutical products and processes. PDA J Pharm Sci Technol., Jul-Aug;53(4):186-201.

Suvarna, K., Lolas, A., Hughes, P., Friedman R. (2011). Case Studies of Microbial Contamination in Biologic Product Manufacturing. American Pharmaceutical Review, Jan/Feb 14(1).

Yabuuchi, E., Kawamura, Y., & Ezaki, T. (2005). Genus VII. Ralstonnia.  In Bergey’s Manual of Systematic Bacteriology (2nd ed., Vol. 2, pp. 609-621). New York: Springer.