Erysipelothrix

From MicrobeWiki, the student-edited microbiology resource

A Microbial Biorealm page on the genus Erysipelothrix

Classification

Higher order taxa

Bacteria; Firmicutes; Mollicutes; Anaeroplasmatales; Erysipelotrichidae; Erysipelothrix

Species

Erysipelothrix rhusiopathiae, Erysipelothrix tonsillarum, Erysipelothrix inopinata


Description and significance

Erysipelothrix are pathogenic bacteria that infect over 50 animal species, specifically domesticated pigs. There are three species: Erysipelothrix rhusiopathiae, E. Tonsillarum, and E. inopinata, each of which varies in its virulence between its two different strains. The smooth strain of each species is pathogenic, while the rough is not. Erysipelothrix rhusiopathiae was first isolated by Koch in 1876. This was the only known species until a subsequent species was discovered in the tonsils of apparently healthy pigs. This new species was named E. Tonsillarum. The third species, Erysipelothrix inopinata was first isolated in the course of sterile filtration of vegetable peptone broth.

Genome structure

The USDA Microbial Genomics Stakeholder Workshop for Animal Health and Food Safety Pathogens considered sequencing Erysipelothrix rhusiopathiae as a swine pathogen. Sequence results are pending.

Cell structure and metabolism

Erysipelothrix is a chemoorganotrophic facultative anaerobe with a respiratory metabolism; it is weakly fermentative. Erysipelothrix is gram positive but may appear gram negative because it decolorizes easily. Cells are catalase-negative and oxidase negative. Erysipelothrix is non-encapsulated, nonsporulating and nonmotile. Its slender rods have rounded ends and are straight or slightly curved, but tend to form long filaments. Its cell wall is what helps to differentiate these bacteria from others with a B-cell wall type in which the peptide bridge is formed between amino acids at positions 2 and 4 of adjacent peptide side chains. This distinguishes Erysipelothrix from other bacteria because most others have the peptide bridge formed between amino acids at positions 3 and 4. Colonies of these bacteria have two distinct forms which include the smooth and a larger round form. The smooth is about .1mm in diameter, convex and circular. The rough form is about .2-.4 mm in diameter, flat with a matte surface. Organisms are either arranged in single short chains, in pairs in a "V" configuration or are grouped randomly. The exact growth requirements of the organism have not yet been determined. However, several amino acids, riboflavin, and small amounts of oleic acid are required, and growth is enhanced by tryptophan. Growth occurs at an optimal temperature of 30-37°C and a pH of 7.2-7.6 and is improved by 5-10% carbon dioxide.

Ecology

Erysipelothrix rhusiopathiae can be found in sewage, the guts of fish and ground contaminated with animal feces. These bacteria are unable to survive for a long period of time in external environments since the rough form prefers slightly acidic conditions at 37oC and the smooth prefers a slightly alkaline environment at 30oC.

Epidemiology

Pathology

Smooth strains of Erysipelothrix are pathogenic and usually enter their host through scratches or puncture wounds on the surface of the skin. Swine Erysipelothrix, called Erysipelas, has four forms; an acute form, a subacute uriticarial form, a chronic non-supportive arthritic form, and a chronic cardiac form. The acute form causes septicemia, fever, anorexia, diarrhea, cyanosis and death. The subacute uriticarial form causes diamond-shaped skin lesions, alopecia, sloughing of tail tip and ear tips, and hyperkeratosis. There are three forms of Erysipelothrix in humans, called Erysipeloid and they are usually occupation related. The first is a localized cutaneous form whose symptoms include a throbbing, itching pain and swelling of the finger or hand. The second is a generalized cutaneous form and the third a septicemic form which is associated with the heart disease endocarditis. Erysipelothrix causes septicemia and eventually death in some wild birds. Although it lives on the skin of fish, they are not infected with the disease. These bacteria also cause joint illness in sheep, lamb, and cattle.

Current Research

Enter summarries of the most rescent research here--at least three required

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Dr. Kirk Bartholomew