Listeria and Erysipelothrix

The aerobic, non-spore-forming, gram-positive rods1) well-recognized human pathogens (e.g., Corynebacterium diphtheriae, Mycobacterium tuberculosis), 2) others are primarily animal pathogens that can cause human disease (e.g., Erysipelothrix rhusiopathiae, Rhodococcus equi)3) opportunistic pathogens typically infecting hospitalized or immunocompromised patie

nts (e.g., Corynebacterium jeikeium).

Identification of the organisms in the laboratory • Gram-positive rods that are uniform in shape include Listeria and Erysipelothrix • The coryneform rods (which include the genus Corynebacterium) comprise a large gr

oup of irregularly shaped rods • long-chain mycolic acids in their cell walls. : acid-fast stain was developed : Nocardia, Rhodococcus, Mycobacterium

BOX 26-1. Listeria and Erysipelothrix

Organism Historical Derivation

Listeria Listeria, named after the English surgeon Lord Lister

L. monocytogenes monocytum, a blood cell or monocyte; gennaio, produce (monocyte producing; membrane extracts stimulate monocyte production in rabbits, but this is not seen in human disease)

Erysipelothrix Erythros, red; pella, skin; thrix, hair (thin, hairlike organism that produces a red or inflammatory skin lesion)

E. rhusiopathiae rhusios, red; pathos, disease (red disease)

Listeria monocytogenes

- 1926: isolated form rabbits with mononucleosis

- 1927: given its name to honor surgeon lord Lister

- 1929: isolated from human with mononucleosis-like disease

History

Physiology and structure- short (0.4 to 0.5 × 0.5 to 2.0 μm) - nonbranching, gram-positive, - facultatively anaerobic rod - growth at a broad temperature range (1°C to 45°C)

and in a high concentration of salt. - motile at room temperature- less so at 37°C, end-over-end tumbling motion : c

old enrichment (growth 4oC)- weak β-hemolysis when grown on sheep blood aga

r plates. - bacteria are widely distributed in nature, - human disease is uncommon and is restricted to s

everal well-defined populations: neonates, the elderly, pregnant women, and patients with defective cellular immunity.

Gram-stain preparation showing L. monocytogenes in cerebrospinal fluid

- β-hemolysin (listeriolysin O), phospholipase: produced by virulent strain only : oxygen labile: antigenic: disrupts phagolysosome

Intracellular Growth - can grow macrophages, epithelial cells, cultured fibriblast - Entry : six or more leucine-rich proteins internalins (eg., InlA, InlB, InlC) glycoprotein receptors (host cells) - bacterium escapes from host vacuole (phagolysosome) : activates exotoxin (listeriolysin O), two phospholipase C- Release into cytosol- Rapid division- Move to cell membrane (ActA)- becomes encapsulated by short actin filaments- facilitates movement to periphery with protrusion and then penetration to neighboring cells- never exposed to humoral immunity- Avoiding antibody-mediated clearance

Pathogenesis and Immunity

Cell-cell transmission

Fusion with another cell

Entry

Escape

actin tail extrusionreplication

Internalins

Listeriolysin OPhospholipase C

ActA

Susceptible host and source of listeriosis

Healthy children and adultsasymptomatic carriage

Pregnant womenasymptomatic carriagesepticemianeonatal disease

Immunocompromized:asymptomatic carriagemeningitissepticemiaSuperinfections

MammalsBirdsFishInsect

Food products

Direct contact

Environment

Clinical diseases

Neonatal Disease

- Mother has no symptomatic illness

- Two forms of neonatal disease

1) Early-onset disease ( 조기형 감염증 )

Granulomatosis infantiseptica

- infection of fetus in utero

- can lead to abortion, disease at birth (sepsis, pneumonia, fetal distress,

seizures, rash, abscesses, and granulomas

- High mortality rate

2) Late-onset disease ( 지연형 감염증 )

- acquired at or soon after birth

- Exposure on vaginal delivery

- can result in meningitis or meningo-encephalitis with sepsis within 2-3 weeks

Adult Disease

- Normal adult are resistant- Common organism in HIV infected and other immunosuppressed patients

: Gastroenteritis : Septicemia :Meningitis – patients with organ transplants, cancer - pregnant women

- Penicillin or ampicillin alone or in combination with gentamicin- prevention and control are difficult : ubiquitous and most infections are sporadic - avoid eating raw or partially cooked foods of animal origin, soft cheeses, and unwashed raw vegetables. - A vaccine is not available, not evaluated prophylactic antibiotic therapy

Treatment, prevention, and control

Erysipelothrix rhusiopathiae

PHYSIOLOGY AND STRUCTURE

-gram-positive, non-spore-forming, facultatively anaerobic rod - distributed worldwide in wild and domestic animals.- pleomorphic, with a tendency to form filaments as long as 60 μm ("hairlike")- microaerophilic, preferring a reduced oxygen atmosphere and supplemented carbon dioxide (5% to 10%). - grayish, α-hemolytic colonies on blood agar are observed after 2 to 3 days of incubation- Animal disease-particularly in swine-is widely recognized, but human disease is uncommon. - Catalase-negative, nonmotile- Produce H2S

Erysipeloid

- Occupational disease of meat and fish handlers

- Caused by

Erysipelothrix rhusiopathiae

Diagnosis and treatment

- Diagnosis

: History and lesion

: Culture of specimen

- Treatment

: Penicillin