Erysipelothrix infection

produces H2S gas and necrotizing infections

W Lee Hand, MD
Hoi Ho, MD

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INTRODUCTION — Erysipelothrix rhusiopathiae, a pleomorphic gram-positive bacillus, causes both a self-limited soft
tissue illness and serious systemic infections. E. rhusiopathiae is widespread in nature and infects domestic animals,
such as swine, which may be the major reservoir of the organism [1]. Erysipelothrix is also found in sheep, horses,
cattle, chickens, crabs, fish, dogs, and cats.

Infection in humans is usually due to occupational exposure. Thus, abattoir workers, butchers, fishermen, farmers,
and veterinarians are at risk for infection with E. rhusiopathiae [2-5].

PATHOGENESIS — Little is known about the pathogenesis of human E. rhusiopathiae infection. The following
observations have been made in in vitro and animal studies:

Virulent organisms have a capsule that is antiphagocytic and may contribute to intracellular survival (in the absence
of opsonization with specific antibody) [6,7].
Intracellular survival of virulent organisms in macrophages is associated with a reduced stimulation of the oxidative
respiratory burst [7].
The SpaA protein is a surface antigen of E. rhusiopathiae. The pathogenic significance of this protein was suggested
in a mouse model in which antibody to SpaA was protective against a lethal challenge [8].
The enzyme neuraminidase may contribute to the pathogenicity of Erysipelothrix, as it caused inflammation and
edema in a rabbit skin test model [9].
CLINICAL FEATURES — The clinical spectrum of human infection includes:

Localized cutaneous infection
Diffuse cutaneous disease
Systemic bloodstream infection
Localized cutaneous infection — The localized cutaneous form of illness, known as erysipeloid of Rosenbach, is the
most common form of human infection due to E. rhusiopathiae [4]. Fingers and/or hands (the sites of exposure) are
usually involved in this infection. As an example, erysipeloid has been described on the fingers or hands of fisherman
or seafood packers who suffer minor trauma while handling contaminated shrimp, crab, or fish [10,11].

Erysipelothrix rhusiopathiae infection in humans:

Infection with Erysipelothrix rhusiopathiae in humans is called "erysipeloid" and dates back to at least 1870.

The disease that is referred to as "erysipelas" in humans is actually a form of cellulitis caused by infection with
Human infections occur primarily via direct contact with infected animals and are, thus, occupational diseases for
people such as veterinarians, abattoir workers and fisherman. (In the later case, erysipelas is called"fish handler's
disease"- the organism is commonly carried subclinically in the mucoid slime covering the scales of fish.)

Infection occurs via contamination of skin wounds (most commonly on the hands) and leads to a unique, raised,
cellulitis lesion that is highly pruritic (intense burning sensation) and characterized by purplish-red discoloration and
edema of the skin.
A more diffuse cutaneous form can also occur when lesions progress from the initial site to other cutaneous sites on
the body. Systemic symptoms (e.g., fever, malaise, muscle aches, headaches) accompany these cutaneous lesions
more commonly than when only solitary skin lesions develop at a wound site.
Occasionally the infection may also spread to deeper tissues, leading to arthritis in the joints of the fingers, or
There are two reports of septicemic Erysipelothrix infection in humans who ate undercooked pork.

Chronic meningitis caused by Erysipelothrix rhusiopathiae
A 47-year-old man presented with headache, nausea, vomiting and fever. Laboratory findings including analysis of
cerebrospinal fluid suggested bacterial meningitis. Erysipelothrix rhusiopathiae was identified in cultures of
cerebrospinal fluid. The patient recovered without any neurological sequelae after antimicrobial treatment. It is
interesting that intracranial infection by E. rhusiopathiae reappeared after scores of years and that it presented with
absence of an underlying cause or bacteraemia.

A Case of Multiple Brain Infarctions Associated With Erysipelothrix rhusiopathiae Endocarditis
Sang-Bae Ko, MD; Dong-Eog Kim, MD; Hyung-min Kwon, MD; Jae-Kyu Roh, MD, PhD
A 63-year-old woman was admitted to our hospital because of fever and altered mentality.
Brain magnetic resonance imaging showed multiple infarctions at the basal ganglia,
cerebellum, and subcortical white matter with petechial hemorrhage, which was
more easily seen on gradient echo images. Erysipelothrix rhusiopathiae was cultured
from her blood, and echocardiography showed septic vegetations in the mitral valve. She recovered
fully after 6 weeks of appropriate antibiotic treatment. Arch Neurol. 2003;60:434-436

Necrotizing Fasciitis Caused by Erysipelothrix rhusiopathiae

The paradox of this case is the recovery from the first-day culture of the distinctly uncommon E. rhusiopathiae as the
dominant organism. It is a Gram-positive aerobic or facultatively anaerobic rod, isolated first by Robert Koch from
mice and later by Louis Pasteur from swine.[3] Rosenbach isolated it from a patient with localized skin lesions and
coined the term erysipeloid, implying a forme fruste of erysipelas. The human disease can manifest itself as a
localized skin lesion (erysipeloid), a diffuse cutaneous eruption with systemic symptoms, or bacteremia sometimes
associated with endocarditis.[3] The route of transmission of E. rhusiopathiae to humans is usually by direct contact
between contaminated fish or fish products, animals or animal products, or soil and a break in the skin.[3] Our
patient's pet goldfish is a likely source of infection through her touching the fish or the fish tank and then scratching
her inner thigh. In a study in Sweden, E. rhusiopathiae was isolated from 60% of the cod and 30% of the herring
tested,[4] but no studies were performed in exotic or pet fish.