Difference between revisions of "Erysipelothrix"
|Line 1:||Line 1:|
Latest revision as of 21:42, 30 July 2010
A Microbial Biorealm page on the genus Erysipelothrix
Higher order taxa
Bacteria; Firmicutes; Mollicutes; Anaeroplasmatales; Erysipelotrichidae; Erysipelothrix
Erysipelothrix rhusiopathiae, Erysipelothrix tonsillarum, Erysipelothrix inopinata
Description and significance
Erysipelothrix are pathogenic bacteria that infect over 50 animal species, but are most commonly found in domesticated pigs. There are three species: Erysipelothrix rhusiopathiae, E. Tonsillarum, and E. inopinata, each of which have a smooth strain and a rough strain which vary in virulence. 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, which was named E. Tonsillarum. Then a third species, Erysipelothrix inopinata was first isolated in the course of sterile filtration of vegetable peptone broth.
The USDA Microbial Genomics Stakeholder Workshop for Animal Health and Food Safety Pathogens considered sequencing Erysipelothrix rhusiopathiae as a swine pathogen. However, the organization chose another organism to sequence, and there are no current plans to sequence Erysipelothrix rhusiopathiae.
Cell structure and metabolism
Erysipelothrix are chemoorganotrophic facultative anaerobes with a respiratory metabolism and are weakly fermentative. Erysipelothrix are gram positive but may appear gram negative because they decolorize easily. Their cells are catalase-negative and oxidase negative.
Erysipelothrix are non-encapsulated, non-sporulating and non-motile. Their slender rods have rounded ends and are straight or slightly curved, but tend to form long filaments. The cell wall is what helps to differentiate these bacteria from others with a B-cell wall type because 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 are the smooth and a larger rough 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 as 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, a pH of 7.2-7.6 and is improved by 5-10% carbon dioxide.
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 37°C and the smooth prefers a slightly alkaline environment at 30°C.
Since the late 1800’s Erysipelothrix rhusiopathiae has been recognized as a cause of infections in both domesticated animals and humans. It has been the source of many diseases in turkey, chicken, ducks, emus, and sheep. Most importantly, it is the etiological agent of swine erysipelas. Most human cases are the result of the occupational hazards of working with animals and animal waste products. Recently, it has been suggested that incidence of human infection could be declining due to technological advances in animal industries. But infection still occurs in certain environments such as Japan, where there are animal hygiene problems, and Western Australia where there are many lobster fisherman and handlers.
Infection by this organism is often misdiagnosed because of difficulty in isolation and identification and its close resemblance to other infections. The bacteria resides deep in the skin, making culturing it a lengthy process. Due to the difficulty in culturing, diagnosis is additionally complicated. However, blood samples or tissue biopsies can be taken in order to isolate the organism more easily for diagnosis of disease.
There have been many recent studies leading to advances in molecular approaches to the diagnosis of an E. rhusiopathiae infection. Understanding of Erysipelothrix rhusiopathiae taxonomy and pathogenesis has also been greatly improved by recent studies. Although antibiotic treatments such as ampicillin and penicillin have been discovered to be effective, it has been shown that containment and control procedures are a far more effective way to reduce infection in both humans and animals.
Smooth strains of Erysipelothrix are pathogenic and usually enter their host through scratches or puncture wounds on the surface of the skin, while rough strains are non-pathogenic.
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 occupationally 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.
There are currently many studies investigating the epidemiology and pathology of E. rhusiopathiae due to its pathogenic nature:
- The Jones Laboratory of Saint Xavier University in Chicago investigates plasmids isolated from wild-type Erysipelothrix rhusipathiae in search of virulence genes.
- In 1997, Dr. John Timoney of the American College of Veterinary Microbiologists, was recognized for his continuous research in the pathogenisis, epizootology and immune response of Erisipelothrix rhusiopathiae.
- In Duebendorf Switzerland, scientists are currently studying the oral efficacy of vaccination against E. rhusiopathiae in Slovakian pig herds.
- J. Chirico et al. are currently studying the role of mites in the transmission of E. rhusiopathiae.
- Brooke, CJ, Riley TV. (1999). Erysipelothrix rhusiopathiae: bacteriology, epidemiology and
clinical manifestations of an occupational pathogen. Journal of Medical Microbiology, 48(9), 789-99. http://www.medscape.com/medline/abstract/10482289?src=emed_ckb_ref_0
- DNA Databank of Japan. (2006). TX Search Taxonomy Retrieval. Retrieved October 3,
- Eriksson, J.C., Fossum, O., Jansson, D. (2003). The poultry red mite, Dermanyssus
gallinae, a potential vector of Erysipelothrix rhusiopathiae causing erysipelas in hens. Medical and Veterinary Entomology, 17(2), 232.
- Erysipelothrix rhusiopathiae. (1999-2006) Provet Healthcare Information.
- Fidalgo, SG, Riley TV. (2004). Detection of Erysipelothrix rhusiopathiae in clinical and
environmental samples. Methods in Molecular Biology. 268, 199-205. http://www.medscape.com/medline/abstract/15156031?queryText=erysipelothrix%20infections
- Jackwood, D.J. (1999) American College of Veterinary Microbiologists [Electronic
Version]. Retrieved October 3, 2006, from http://220.127.116.11:8080/prokPUB/index.htm
- Jones, J. C. (2006). The Jones Laboratory at Saint Xavier University. Retrieved October
3, 2006, from http://18.104.22.168:8080/prokPUB/index.htm
- Sawada Takuo. (2001). Distribution of Antibody against Erysipelothrix rhusiopathiae in Cattle.
Clinical and Diagnostic Lab Immunology. 8(3), 624-627.
Edited by Jacqueline Schmiedecke, Lucas Bernacki, Jocelyn Brickett and Kathleen Strampfer, students of Dr. Kirk Bartholomew