Erysipelothrix rhusiopathiae (Baker-Rosenbach Erysipeloid; Pig erysipela; Swine erysipela): Culture; Molecular diagnosis (PCR)
Erysipelothrix rhusiopathiae is a gram - positive bacillus global distribution of the genus Erysipelothrix, family Erysipelotrichaceae. This bacterium is primarily considered an animal pathogen, which causes the disease erysipelas pig, also known as "Swine erysipelas", an endemic disease in pig farms in countries with which can cause significant economic losses. Besides pigs, other species that may be affected include turkeys, poultry, sheep, fish and reptiles. Erysipelothrix rhusiopathiae can also affect people causing erisipeloide Baker-Rosenbach.
This bacterium is a gram - positive bacillus, not sporulated, which has high to adverse environmental conditions resistance and can remain for months in animal tissues, either frozen meat, fish meal, meat salted or smoked, among others. Erysipelohrix rhusiopathiae and Erysipelothrix tonsillarum: two species by their phylogenetic differences are currently supported. Erysipelothrix rhusiopathiae presents two types of colonies: a smooth colonies that are smaller and which are formed by short rods, and roughened colonies formed by longer rods arranged unbranched chain. 23 serovars are differentiated and type N. According to studies of DNA-DNA hybridization exist four species, although two that correspond respectively to serovars 3 and 18, are not assigned species name. Erysipelothrix rhusiopathiae to include serovars 1, 1b, 2, 4, 6, 8, 9, 11, 12, 15, 16, 17, 19, 21 and N); Erysipelothrix tonsillarum to include serovars 7, 10, 14, 20, 22 and 23. It is very distributed in nature, being found in the soil as a saprophyte, or decaying organic matter. It is considered both a diner as a pathogen, depending on the animal species. It is not pathogenic to fish, and can survive for long periods in the outer mucosa biofilm (slime) of a wide variety of fish, both freshwater and saltwater, cephalopod and crustaceans. In fish has been isolated even frozen and feces of animals that eat fish. For other animals, as with pigs, sheep and cattle can provoke disease but has also been isolated from healthy pigs. As a Gram - positive bacterium can be confused with Listeria monocytogenes, Corynebacterium pyogenes, Streptococcus suis, etc.
The life cycle of this organism involves a host where it multiplies, the main natural reservoir pork. It is an opportunistic pathogen that survives multiply intracellularly within macrophages and polymorphonuclear leukocytes (PMN) due to its antioxidant enzymes that confer protection against reactive oxygen species and phospholipases. This organism adheres to liver cells as well as heart valves of animals. Erysipelothrix rhusiopathiae has virulence factors involved in its pathogenicity mechanism. The hyaluronidase and neuraminidase enzymes allow you to invade the host. Hyaluronidase facilitates the spread tissue and neuraminidase produced cleavage of sialic acid, a widely distributed molecule on the surface of eukaryotic cells that may serve as a nutritional requirement for Erysipelothrix rhusiopathiae.
Erysipelothrix rhusiopathiae transmission occurs through ingestion or inhalation of bacilli from secretions or body exudates, contaminated food and water and transplacental. The spread of bacteria can occur through the wash water and the ditches, the incorporation of animals affected to unaffected animals and through the supply of contaminated food and water.
In animals, Erysipelothrix rhusiopathiae infection primarily affects pigs and poultry such as chickens or turkeys. In pigs it causes (Swine erysipelas) swine erysipelas that can follow an acute or chronic course. The acute form is characterized by septicemia box with hyperthermia, joint pain, stiff gait, prostration and rapid death with disseminated intravascular coagulation syndrome, vascular necrosis and rhomboid skin infarcts. Sometimes infection is accompanied by anorexia, tachycardia, dyspnea, conjunctivitis, mucosal congestion and gastrointestinal disorders. In birds, such as turkeys, erysipelas is an acute infection with septic thrombosis, and pulmonary edema and cardiac hemorrhage, parenchymal necrosis and disseminated. In cases of chronic infection can cause arthritis, endocarditis and skin necrosis. Chronic presentation produce greater economic impact due to deaths as a result of endocarditis and declining growth rate of animals. Infection also occurs in fish - eating birds, such as penguins zoo fed fish. In aquatic animals in captivity zoos and aquariums, cetaceans are most susceptible, and is manifested as acute septicemia or multifocal dermatitis.
In people, Erysipelothrix rhusiopathiae infection usually manifests as a lesion skin well defined called erisipeloide Baker-Rosenbach, which is generally located on the back of the hands and fingers, reddish although rarely can be located in the palm hands, forearms, arms, face and legs. These lesions may be asymptomatic or accompanied by mild itching, pain and fever. It may also present the digestive form or disseminated form. The most serious form of presentation is septicemic, low incidence, which may be associated with meningitis and septic arthritis and can lead to endocarditis. In the latter embodiment, the disease can be fatal. The disease caused by this organism in humans (Erysipeloid) is considered an occupational disease because it particularly affects animal breeders, veterinarians, butchers, furriers, butchers, fishmongers, fishermen and housewives way. In most environments sailors infections scratch or puncture skin scales, teeth, bones or fish bones or lobster.
Recommended tests for diagnosis:
The diagnosis is based on microscopic observation, culture, or in molecular diagnostic methods (PCR). Molecular methods (PCR), offer the advantage of providing a quick and specific diagnosis.
Typically , the culture samples taken from joints, heart, and other organs. Cultivation provides very small colonies in 24 to 48 hours, and may be difficult to isolate in highly contaminated samples. It takes at least 3 days to provide results with identification, and about 10 days to identify the serovar.
Tests in IVAMI:
- Detection by isolation by culturing in selective media.
- Molecular diagnosis (PCR), to detect DNA of Erysipelothrix rhusiopathiae.
- Sample of infected tissue.
- Whole blood collected with EDTA (2 to 5 mL) (in generalized infection).
Preservation and shipment of sample:
- Refrigerated (preferred) for less than 2 days.
- Frozen: over 2 days.
- Culture: 72 hours.
- Molecular diagnosis (PCR): 24 to 48 hours.
Cost of the test: