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What is the only pathogenic Listeria species for warm-blooded animals and humans?
Listeria monocytogenes
What is the Gram reaction and shape of Listeria monocytogenes?
Gram-positive, small rods
How does Listeria monocytogenes appear in older cultures?
Gram-negative in young cultures, almost entirely Gram-negative in old cultures
What type of motility does Listeria monocytogenes exhibit?
Tumbling motility with peritrichous flagella
What is a distinguishing feature of Listeria monocytogenes morphology?
Shows slight clubbing, diphtheroid appearance, and coccoid forms
On what media does Listeria monocytogenes grow?
Most ordinary media, though growth is never abundant
What is the appearance of Listeria monocytogenes colonies on blood agar?
Small, flat, bluish-white, transparent
What type of hemolysis does Listeria monocytogenes exhibit?
Beta-hemolysis with narrow zones
What is the characteristic growth pattern of Listeria monocytogenes in gelatin?
Inverted fir tree formation
How does Listeria monocytogenes differ from Erysipelothrix rhusiopathiae biochemically?
Produces catalase
How many O and H antigens does Listeria monocytogenes have?
15 O antigens, 5 H antigens
How many serotypes and subtypes exist for Listeria monocytogenes?
16 serotypes, 14 subtypes
How do the neural and visceral forms of Listeria monocytogenes infection differ?
Neural form: via trigeminal nerve; Visceral form: via ingestion
What is the major mode of infection for visceral Listeria monocytogenes infection?
Ingestion
What type of infections are most Listeria monocytogenes cases classified as?
Exogenous infections
What reproductive effect does Listeria monocytogenes have in cows and ewes?
Causes abortion without neural manifestations
What is the common presentation of Listeria monocytogenes in chickens and turkeys?
Septicemic form with necrotic foci in the liver and myocardium
Where is Listeria monocytogenes commonly found?
Ubiquitous in nature, present in animal and human feces
How does pH affect Listeria monocytogenes survival?
Survival is poor below pH 5
Why is Listeria monocytogenes more heat-tolerant than most non-sporeforming bacteria?
It has increased resistance to environmental conditions
Where is Listeria monocytogenes commonly harbored in swine?
Tonsils
What enables Listeria monocytogenes to invade host cells?
Surface protein internalin interacts with E-cadhedrin
How does Listeria monocytogenes escape from the phagosome?
Produces hemolysin listeriolysin O
What is the role of listeriolysin O?
Lyses cholesterol-containing membranes of eukaryotic cells
How does Listeria monocytogenes move within host cells?
Induces actin polymerization to push against the cell membrane
What are filopods in Listeria monocytogenes infection?
Protrusions formed by bacterial movement within cells
Why is it difficult to recover Listeria monocytogenes from brain tissue?
Requires prolonged cold enrichment up to 12 weeks
What temperature is used for cold enrichment of Listeria monocytogenes?
Refrigerator temperature
On what medium is Listeria monocytogenes routinely isolated?
Blood agar
What environmental conditions stimulate Listeria monocytogenes growth?
5-10% CO2
What is the appearance of Listeria monocytogenes colonies under transmitted light?
Round, entire, glistening, bluish
How does Listeria monocytogenes survive in the environment?
Resistant to drying
Where can Listeria monocytogenes persist for months?
Food, straw, soil, shavings
What immune response is most important in Listeria monocytogenes infections?
T-cell mediated activation of macrophages
What is the role of humoral immunity in Listeria monocytogenes infections?
Not clearly understood
Is immunization commonly practiced against Listeria monocytogenes?
No, immunization is not widely practiced
What antibiotics are effective against Listeria monocytogenes?
Chloramphenicol, tetracycline, sulfonamides, penicillin
What are the preferred treatments for Listeria monocytogenes infections in humans?
Erythromycin and ampicillin
What is the causative agent of swine erysipelas?
Erysipelothrix rhusiopathiae
What are the five disease forms of Erysipelothrix rhusiopathiae?
Diamond skin disease, Septicemia, Polyarthritis, Endocarditis, Abortion
Which animals are affected by Erysipelothrix rhusiopathiae?
Swine, lambs, calves, turkeys, ducks
What is the skin lesion caused by Erysipelothrix in humans called?
Erysipeloid
What is the Gram reaction of Erysipelothrix rhusiopathiae?
Gram-positive but easily decolorized
Does Erysipelothrix rhusiopathiae form spores?
No
What is a distinguishing feature of rough forms of Erysipelothrix?
Exhibit long filaments
Does Erysipelothrix rhusiopathiae have flagella?
No
What differentiates Erysipelothrix rhusiopathiae from Listeria monocytogenes?
Absence of DL-diaminopimelic acid in the cell wall
What type of colonies does Erysipelothrix form on serum or blood agar?
Tiny, clear, and glistening
What is the appearance of Erysipelothrix on blood agar?
Initially greenish discoloration, later definite clearing
What is the characteristic growth pattern of Erysipelothrix in gelatin?
Bottle brush-like
How many serotypes of Erysipelothrix rhusiopathiae exist?
22 serotypes
Which serotypes are most commonly associated with septicemia and tonsils?
Serotypes 1 and 2
How is Erysipelothrix rhusiopathiae shed?
Urine, feces, saliva, vomitus
What are the primary routes of infection for Erysipelothrix rhusiopathiae?
Oral, Skin scarification
Why is Erysipelothrix resistant in the environment?
Resistant to drying, smoking, pickling, and salting
Where is Erysipelothrix commonly found?
Areas with alkaline soil, tonsils, and reticuloendothelial tissue
What are the symptoms of acute Erysipelothrix infection?
High fever (41.1°C), deep red skin patches, spleen and lymph node enlargement, kidney hemorrhages
What is another name for the less severe form of Erysipelothrix?
Diamond skin disease
What is the appearance of skin lesions in diamond skin disease?
Red rhomboidal blotches that become necrotic
What characterizes the severe septicemic phase of Erysipelothrix infection?
Increased SGOT, hypoglycemia, increased RBC destruction
What causes high fever in severe Erysipelothrix infection?
Endotoxin, a glycoprotein producing shock effect
What cardiac condition does chronic Erysipelothrix infection cause?
Vegetative endocarditis
What joint condition is associated with chronic Erysipelothrix?
Arthritis
Which animals are more susceptible to the arthritic form of Erysipelothrix?
Older animals
What happens to cartilage in chronic Erysipelothrix arthritis?
Erosion of cartilage, increased synovial fluid
Why is Erysipelothrix difficult to isolate in chronic cases?
Organisms become deeply embedded in tissues
How does Erysipelothrix enter sheep?
Through docking and castration wounds
What disease does Erysipelothrix cause in cattle?
Arthritis in tibio-tarsal, stifle, and carpal joints
What condition does Erysipelothrix cause in birds?
Bluecomb, cyanotic skin, diarrhea, massive hemorrhages
Which laboratory animals are highly susceptible to Erysipelothrix?
White mice
Which aquatic animals can be infected by Erysipelothrix?
Crocodiles and bottle-nosed dolphins
What type of immunity protects against Erysipelothrix?
Serum and cell-mediated immunity
What test is used to assess immunity against Erysipelothrix?
Growth-agglutination test (Wachstumsprobe test)
Who developed the first attenuated vaccine for Erysipelothrix?
Pasteur and Thiullier
What is the name of the attenuated vaccine for Erysipelothrix?
EVA (erysipelas vaccine avirulent)
What types of vaccines are available for Erysipelothrix?
Killed and attenuated vaccines
What disease must Erysipelothrix be differentiated from in pigs?
Hog cholera
How do pigs with hog cholera appear compared to those with Erysipelothrix?
Hog cholera: lethargic, Erysipelothrix: bright and alert
What is a key difference in eating behavior between hog cholera and Erysipelothrix infections?
Hog cholera: stop eating
What symptom is common in hog cholera but not in Erysipelothrix?
Diarrhea
How does spleen appearance differ between hog cholera and Erysipelothrix?
Hog cholera: enlarged bluish-red spleen
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