Corynebacterium/Trueperella/Rhodococcus Flashcards
What is Corynebacterium?
- Gram positive
- Nonspore forming rod (pleomorphic)
- Club shaped
- Several species
What are the species of Corynebacterium?
- C. equi - Rhodococcus equi
- C. suis - Actinbaculum suis
- C. pyogenes - Trueperella pyogenes
What is C. diphtheriae?
- Causes diphtheria in children
- Diphtheria toxin
- A-B toxin, gene on a prophage
- Not an animal pathogen
What is C. ulcerans?
- Emerging pathogen
- Produces diphtheria toxin
- Causes diphtheria
- An animal Pathogen
- hence a zoonotic agent
What diseases does C. pseudotuberculosis cause?
- Sheep & Goats: Caseous Lymphadenitis
- Horses:
- Ulcerative Lymphangitis
- External (Pigeon Fever) abscesses
- Internal abscesses
What are the Biotype of . pseudotuberculosis?
- Ovis - Sheep and goats
- Nitrate reduction test negative
- Equi - Horses and cattle
- Nitrate reduction test positve
- PCR assay can be used to differentiate
What are the Virulence factors of C. pseudotuberculosis?
- Facultative intracellular pathogen
- Surface lipid coat protects the organism in teh phagocytic cells
-
Exotoxin: Phospholipase D (PLD) - Protective antigen
- Cytolytic
-
Mycolic acid: Protection
- Permits the organism to survive intracellularly
What is the pathogenesis of C. Pseudotuberculosis?
- Organism is present in the GI tract and soil
- Enters through skin breaks / Ingestion or inhalation
- Form micro abscesses at the site of entry
- Disseminated by phagocytic cells via lymph or blood to lymph nodes
- Phospholipase D increases vascular permeabiliy and spreads the infection
What is Caseous Lymphadenitis?
- Chronic and contagious disease in sheep and goats
- Abscesses in the skin, lymph nodes and internal organs
- Two forms:
- External: Infection of the skin, subcutaneous tissue and peripheral lymph nodes
- Internal: Abscesses in lungs, liver, kidneys, spleen and internal lymph nodes
What are the forms of C. pseudotuberculosis in Horses?
- 3 forms:
- Ulcerative lymphangitis - less common
- External Abscesses
- Internal Abscesses
What is Ulcerative Lymphangitis?
- Inflammation of the lyphatic vessels
- Formation of abscesses on the legs
- Abscesses break and exude thick greenish pus
- Resembles farcy
- May spread to internal organs
What are External Abscesses of C. pseudotuberculosis?
- Single large abscess, often in the pectoral region
- Pigeon fever or Breast bone fever
- Thick capsule and filled with yellow to tan pus
What are Internal Abscesses with C. pseudotuberculosis?
- Difficult to diagnose
- Weight loss, fever, depression, colic
- Most often in the liver
How is C. pseudotuberculosis diagnosed?
- External abscesses are easy to diagnose
- Bacteriologic culture
- Diptheroid rods in stained smears of the pus
- Isolation and PCR confirmation
How is C. pseudotuberculosis Treated?
- Antibiotics:
- Penicillin, ampicillin, erythromycin, gentamicin, chloramphenicol and tetracycline with rifampin (penetrates the abscess)
- Not very effective because of the thick abscess capsule and intracellular location
- External abscesses - Surgical incision to drain
Is there a vaccine for C. pseudtuberculosis?
- Inactivated whole cell wall and supernatant containing phospholipase D (protective)
- Commercially available
What Corynebacterium species cause UTIs?
- C. renale* most common
- C. pilosum
- C. cystitidis
- Predominantly in cows
What are the Virulence factors of C. renale?
- Fimbriae - Attachment
- Urease - Ammonia
What is he pathogenesis of C. renale?
- Attachment to the epithelial cells of the urinary reproductive tracts
- Ascends to the kidneys to cause pyelonephritis
What Diseases does C. renale / C. cystitidis cause in Cattle?
- Hemorrhagic cystitis
- ulceration of the bladder
- Ureteritis and Pyelonephritis
- Clinical Signs:
- Fever
- Anorexia
- Arched back
- Frequent urination
- Urine will have albumin
- Leukocytes
- Blood clots
What disease does C. pilosum cause in Cattle?
- Less pathogenic
- Mild cystitis
- Rarely pyelonephritis
What disease does C. pilosum / cystitidis cause in Sheep/Goats?
- Rarely causes UTI
- Cause preputial ulcerative dermatitis “Posthitis”
- Normally inhabit the prepuce
- High protein diet is a predisposing factor
- High urea excretion leads to increased ammonia
What is Posthitis?
- Ammonia causes irritation leading to inflammation and ulceration of the preputial skin
- Spreads from the orifice to the mucosa
- Secondary bacterial infection
- Crusting, swelling and pain
- Pooled urine and pus could cause necrosis
- Ewes: ulcerative vulvovaginitis
What is the treatment for C. pilosum / renale / cystitidis
- Antibiotics:
- Penicillin and Trimethoprin-Sulfamethaxazole
- Posthitis:
- Reduction in protein diet
- Antibaacterial ointment or spray
What is C. ulcerans
- A human pathogen
- causes diphtheria
- Produces diphtheria toxin and phospholipase D
- Commensal in animals:
- Cattle, sheep, goats, pigs, dogs, and cats
- Mastitis in dairy cows
- lymphadenitis in sheep and goats
- Rhinitis in dogs and cats
- Zoonotic
What is Rhodococcus?
- Several species
What diseases does Rhodococcus equi cause?
- Causes pneumonia in foals
- Mesenteric Lymphadenitis and arthritis in foals
- Tubercle lesions in cervical lymph nodes swine and cattle
- Pneumonia in AIDS patients
What is Rhodococcus equi?
- Formally Corynebacterium equi
- Pleomorphic: Coccoid (solid medium) to rods (liquid medium)
- Gram Positive
- Nonspore forming
- Nonhemolytic, does produce hemolysin, phospholipase
- Synergestic with hemolysin of Staphylococcu aureus, C. Pseudotuberculosis, L. monocytogenes (Positive CAMP)
What are the antigenic characteristics of Rhodoccocus?
- Serotyping based on capsular polysaccharide
- >10 serotypes
- Predominant serotype in the US is serotype 1
What are the Virulence factors of Rhodococcus?
- Virulence is due to a plasmid
- Large plasmid (80 - 90 Kb) that codes for surface proteins called virulence associated proteins (VAP)
- Function of VAP is not known
- Lipid layer with mycolic acid
What is the mode of infection of Rhodococcus?
- Soil borne infection
- Also present in feces of animals
- Inhallation of the dust
What is the pathogenesis of Rhodococcus?
- Enter the alveoli and is phagocytosed by macrophages
- Multiply in the phagocytesand eventually destroy the alveolar macrophages
- Death of the macrophages is followed by neutrophilic infiltration and abscess formation
What is R. equi penumonia in Foals?
- Generally between 4 - 12 weeks of age
- Rarely in adult horses
- Onset is insidious
- Anorectic with nasal discharge
- Mortality is high (64%)
- Lymphadenitis is common
- Lymph nodes in the hed are generally not involved
Does R. equi infect other animals?
- Swine - Lymphadenitis of the submandibular and cervical lymph nodes
- Sheep & Cattle - Pneumonia
- Goats - Lesions in the liver
How is R. equi diagnosed?
- Bacterial culture
- Sample - Transtracheal aspirates
How is R. equi Treated?
- Antibiotics:
- Penicillin, Doxycycline, Erythromycin, Lincomycin, and Gentamicin
- Erythromycin or penicillin in combo with rifampicin
What is Trueperella pyogenes?
- Gram Positive
- Rods
- Beta hemolytic
- Pus forming
- Abscesses in all animals
- more common in cattle, sheep, goats, and swine
- Inhabitant of the mm of respiratory, GI, and genital tracts
- Most common opportunistic pathogen
What are the Virulence Factors of Trueperella pyogenes?
- Several toxins and enzymes
- Hemolysin: Pyolysin O (PLO) - Protective
- Neuramindase -Adhesion
- Extracellular matrix-binding protein - Adhesion
- Exoenzymes: Proteases, DNAses, etc.
What is Pyolysin?
- Primary virulence factor - protective antigen
- Lyses RBCs but also cytotoxic to other cells (WBCs and macrophages)
- Mutants that lack the gene are less virulent
What is Neuraminidase?
- Sialidase: Cleaves sialic acid from CHO or glycoproteins
- Two enzymes:
- NanH: Cell-wall associated 107 kDa Protein
- NanP: 186.8 kDa protein
- Role in adhesion
- Decrease the viscosity o mucus
What is the pathogenesis of Trueperella pyogenes?
- Normally present on the mucous membrane
- Entry requires some insult or injury to the mm
- Could be a primary pathogen but most often is a secondary invader
- May get disseminated and even cause abortion
- Most often infection is localized causing abscesses
What diseases does Trueperella pyogenes cause in animals?
- Cattle - Liver abscesses
- Cows - Summer mastitis
- Dairy - Metritis, endometritis
- Swine - septic arthritis
- Foot rot in cattle, sheep, goats
What are Liver abscesses in Cattle?
- Second most common etiological agent
- Source is probably the ruminal wall
- Reaches liver via portal vein
What is Summer Mastitis?
- Mastitis in dry cows and heifers
- Mastitis with thick purulent secretions
- Entry through tat canal
- Common during fly season
- fly bites provide portal of entry
What is Foot rot?
- Cattle - associated with F. necrophorum
- Sheep and goats - associated with D. nodosus
What is Septic Arthritis in Swine?
- Caused by Trueperella pyogenes
- Appears after farrowing
- Source of infection is probably the uterus
What other infections does Trueperella pyogenes cause?
- Umbilical infections
- Traumatic reticulitis (Hardware Disease)
- Internal abscesses in all animals
How is Trueperella pyogenes diagnosed?
- Bacterial culture - Isolation and Identificatoin
- Minute colonies in blood agar with distinct narrow zone of hemolysis
How is Trueperella pyogenes Treated?
- Antibiotics:
- Penicillin, ampicillin, chloramphenicol, erythromycin, sulfamethazine, and tetracyclines
- Response to antibiotics is poor
- Capsulation
- Antibiotics bind to proteins in the pus
Is there a vaccine for Trueperella pyogenes?
- None available
- Bacterin may be of some help
- Pyolysin as a subunit vaccine
