Burkholderia pseudomallei

Burkholderia pseudomallei on an agar plate in a Petri dish

Burkholderia pseudomallei is a Gram-negative, bipolar, aerobic, motile, rod -shaped bacterium. It's like Burkholderia mallei a pathogenic Burkholderia species and causes melioidosis in humans. B. pseudomallei is like B. mallei on the list for potential biowarfare agents.

Taxonomy

Since its discovery, the pathogen was classified in many systematic groups: Bacillus, Corynebacterium, Mycobacterium, Peiffer Ella, Loefflerella, Malleomyces, Actinobacillus, Pseudomonas. The genus Burkholderia is associated with the bacterium only since the early 90s.

Mark

B. pseudomallei 5 microns long and 0.4 to 0.8 microns in diameter and can move by flagella. The bacteria can grow in various culture media, but especially in those containing betaine and arginine. There are different serotypes of this bacterium, of which / ara and Type II/ara- are clinically most important type I. They are distinguished by their ability in the laboratory to metabolize L-arabinose.

In vitro the growth optimum is at a temperature of 40 ° C with a neutral or slightly acidic pH - value place (pH = 6.8 to 7.0 ). Most strains are for the fermentation of sugars without gas formation capable (most importantly glucose and galactose, older cultures could also metabolize maltose and starch ). The bacteria produce both exotoxins and endotoxins. The role of toxins in the pathogenesis of melioidosis is not fully understood.

Occurrence

The bacterium B. pseudomallei is endemic in the soil and water, both in Southeast Asia as well as in northern Australia occurring. The clinically important serovars Type I / ara and Type II/ara- correspond to the above-mentioned geographical areas, hardly differ in their pathogenicity.

Disinfection

B. pseudomallei sensitive to many disinfectants, including benzalkonium chloride, iodide, lead chloride, potassium permanganate, 1 - % sodium hypochlorite, 70 - % ethanol, 2 - % glutaraldehyde and less effective phenols. The microorganisms are killed by temperatures exceeding 74 ° C for 10 minutes or UV irradiation.

Medical importance

B. pseudomallei causes melioidosis in humans. There are various forms of the disease. A B. pseudomallei sepsis has a mortality rate of 80 % if left untreated. The determination of B. pseudomallei as a pathogen in the laboratory can be very difficult, especially in the Western Hemisphere, where B. pseudomallei is very rare.

The relative ease of cultivation has raised together with the most important symptoms of ( melioidosis ) infections, interest in B. pseudomallei and the closely related B. mallei as a potential biowarfare agents.