Erysipelothrix rhusiopathiae

Erysipelothrix rhusiopathiae is a Gram-positive, catalase-negative, rod-shaped, non-spore-forming, nonacid-fast, nonmotile bacterium. Distributed worldwide, E. rhusiopathiae is primarily considered an animal pathogen, causing the disease known as erysipelas that may affect a wide range of animals. Pigs, turkeys and laying hens are most commonly affected, but cases have been reported in other mammals, birds, fish, and reptiles. In pigs, the disease is known as 'diamond skin disease'. The bacterium can also cause zoonotic infections in humans, called erysipeloid. The human disease called erysipelas is not caused by E. rhusiopathiae, but by various members of the genus Streptococcus. Erysipelothrix rhusiopathiae was first isolated by Koch in 1876. A few years later the bacterium was recognised as the cause of erysipelas in pigs and in 1884 the organism was first established as a human pathogen. In 1909, the genus was named Erysipelothrix. In 1918 the name Erysipelothrix rhusiopathiae was introduced and in 1920 it was designated as the type species of the genus. Erysipelothrix rhusiopathiae may be isolated from soil, food scraps, and water contaminated by infected animals. It can survive in soil for several weeks. In pig faeces, the survival period of this bacterium ranges from 1 to 5 months.Erysipeloid is transmitted by several animals, particularly pigs, in which the disease (very common in the past) has several names (swine erysipelas in English, rouget du porc in French and mal rossino in Italian). Urticaria-like lesions, arthralgia, arthritis, endocarditis, and sepsis are the most characteristic features of swine erysipelas. Other animals that can transmit the infection are sheep, rabbits, chickens, turkeys, ducks, emus, scorpion fish, and lobsters.Erysipeloid is an occupational disease, mainly found in animal breeders, veterinarians, slaughterhouse workers, furriers, butchers, fishermen, fishmongers, housewives, cooks, and grocers. One epidemic of erysipeloid was described in workers involved in manufacturing buttons from animal bone. The disease is of economic importance to the pig industries of North America, Europe, Asia, and Australia. In humans, E. rhusiopathiae infections most commonly present in a mild cutaneous form known as erysipeloid. Less commonly, it can result in sepsis; this scenario is often associated with endocarditis.Erysipeloid, also named in the past Rosenbach’s disease, Baker–Rosenbach disease, and pseudoerysipelas, is abacterial infection of the skin caused by traumatic penetration of E. rhusiopathiae.It occurs most commonly as an occupational disease.The disease is characterized clinically by an erythematous oedema, with well-defined and raised borders, usually localized to the back of one hand and/or fingers. The palms, forearms, arms, face, and legs are rarely involved. Vesicular, bullous, and erosive lesions may also be present. The lesion may be asymptomatic or accompanied by mild pruritus, pain, and fever. Erysipelothrix rhusiopathiae may infect a wide range of animals, with or without causing the clinical disease that in animals is termed erysipelas. In pigs, three forms of erysipelas may be seen; acute, subacute or chronic. The acute form is characterised by high fever, anorexia, depression and death of one or more animals. Also, diamond-shaped cutaneous lesions may be seen, these are pathognomonic for erysipelas in pigs. During subacute erysipelas, similar but milder signs than in the acute form are seen. The chronic form may follow from acute or subacute cases or subclinical infections. The chronic form is mostly characterised by arthritis but sudden deaths, due to valvular lesions in the heart, may occur. The bacterium has been isolated from a wide range of avian species and differences in susceptibility depending on species have been suggested. Erysipelas outbreaks have been reported in almost all poultry species. Historically, erysipelas has been considered a disease of significant importance primarily in turkeys. However, an increasing number of outbreaks in laying hen flocks have been reported in several countries. Signs seen during an outbreak of erysipelas in a laying hen flock include sudden onset of high mortality and egg production losses. Various virulence factors have been suggested as being involved in the pathogenicity of E. rhusiopathiae. The presence of a hyaluronidase and neuraminidase has been recognized, and neuraminidase was shown to play a significant role in bacterial attachment and subsequent invasion into host cells. The role of hyaluronidase in the disease process is controversial. The presence of a heat-labile capsule has been reported as important in virulence.