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41 Cards in this Set
- Front
- Back
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Family Pasteurellaceae
Large and diverse: name 4 |
Pasteurella (and Bibersteinia)
Mannheimia Actinobacillus Haemophilus (and Avibacterium) |
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Pasteurellaceae characteristics:
Pasteurella spp and Mannheimia spp. |
small Gram - rods
Non-motile; oxidase + Facultative anaerobes bipolar staining seen using Giemsa stain (poles of a cell stain darker than center of cell) some grow on MAC |
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Family Pasteurellaceae characteristics
Haemophilus spp |
gram negative, small rods (tending to coccobacillary)
require X and V factors for growth (X- haemin that is heat stable (v- (NAD) that is heat labile -present in CHOCOLATE AGAR - 10% CO2 enhances growth motile and facultative anaerobes |
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Media for Haemophilus Species
what 2 types of agar are used? which agar releases V factor? which agar provides X factor? |
1. Chocolate agar: blood agar base at 80c and adding ther red blood cells. Pour the plates when the colour looks like milk chocoate.
Heat releases V factor from the red cells and so provides both X and V factors 2. Blood Agar + Staphylococcus aureus streak BA provides some X factor and the S. aureus provides the V factor |
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Family Pasteurellaceae characteristics
Actinobacillus spp Id |
Gram negative, medium sized rods.
growth on MAC= A. lignieresii, A suis, A equuli - lactose + - urease-+ - "sticky" coloies on BA (primary isolation) growth on Chocolate + 10% CO2 at 37c for 2-3 days = A. pleuropneumoniae |
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Family Pasteurellaceae characteristics
Actinobacillus spp direct microscopy |
**only of value for the granulomatous skin lesions of bovine actinobacillosis.
* greying-white granules washed free of pus: - gram-stained smears from granules (gram (-) rods - histological stained sections to see club colonies |
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What are general characteristics of Pasteurellaceae family?
- Habitat? - clinical conditions in farm animals and horses? |
habitat: mucous membranes- [carriers]
clinical conditions: respiratory disease and septicaemia |
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Pasteurellaceae - general pathogenic mechanisms
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Capsule- antiphagocytic
Fimbrae/ Adhesions- attachment and colonization Exotoxins- RTX |
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Describe what the exotoxins RTX do and give an example.
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RTX (repeat in toxin) = pore forming toxins
- insert directly into cell membrane - pores-lysis-H2O in and ions out! ex. cytolysins; 'APX' toxins |
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Why/How is capsule classed as a virulence factor?
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Evasion of host immune response
Spontaneous acapsular mutants - occur naturally during serial culture (changed colony morphology) Genetically engineered acapsular mutants - id the genes encoding capsule in P. multocida - mutate these genes to inactivate capsule - ex. Koch's molecular postulates of virulence |
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Actinobacillus: general characteristics
A lignieresii A. pleuropneuoniae |
commensals on mucous membranes (upper resp and oral cavity)
- exception A. pleuronpneumoniae - can't survive long periods in environment - carriers important for transmission - variety of infections in animals |
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Actinobacillus:
A lignieresii causes what disease in cattle? |
Timber (wooden) tongue
- pyogranulomatous lesions in cattle (and sheep) - infection through lesions in mouth by rough feed/pasture - spreads to regional lymph node- lymphadenitis |
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Actinobacillus:
A lignieresii: Timber wooden tongue TREATMENT |
isolate affected animals
sodium iodide parenterally or potassium iodide orally streptomycin systemically |
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Differential Diagnosis for Actinobacillus: A lignieresii (Timber wooden tongue)
how to differentiate? |
Bovine actinomycosis (lumpy jaw)
- direct microscopy on pus or exudates - culture on BA and MAC A lignieresii: timber tongue, gram -, grey-white 1 mm granules, not bone, aerobic A bovis: lumpy jaw, gram +, yellow 1-3 mm granules, often in bone, anaerobic |
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Actinobacillus: A. pleuropneumoniae
where found? |
NOT a commensal (remember this was the exception for Actionbacillus)
primary pathogen |
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Actinobacillus: A. pleuropneumoniae
Pathogenesis |
-Fimbriae/adhesions (attachment)
-capsule (antiphagocytic) - TRX toxins (cytolysins; 'Apx' toxins) * remember that TRX toxins are exotoxins that kill cells by lysing them |
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Actinobacillus: A. pleuropneumoniae
Describe Pleuronpneumonia of Pigs |
necrotising, haemorrhagic pneuonia
highly contageous aerosol transmission |
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Actinobacillus: A. pleuropneumoniae
control and treatment |
vaccines: commercial subunit (mix of outer membrane proteins and Apx toxins)
treatment: difficult as many strains are antibiotic resistant |
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sActinobacillus: A. equuli
Describe the disease caused by this pathogen. |
- Sleepy foal disease
- Commensal in reproductive and intestinal tract of Mares - Septicaemia of neonatal foals (acute, potentially fatal) |
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Actinobacillus: A. suis
Describe the diseases caused by this pathogen. |
- commensal in upper resp tract of sows
- septicaemia and resp disease in piglets (rapidly kills infected piglets <3 months old) - can be isolated from horses (similar to A. equuli) |
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Pasteurella multocida
Epidemiology |
habitat: commensals of upper resp
many infections are endogenous (pathogen is present --need predisposing factor) Tonsillar carriers Poor housing/stress Transmitted horizontally |
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Pasteurella multocida
pathogenesis |
capsule: block phagocytosis
adhesions to 'stick to surfaces toxins |
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Pasteurella multocida: cattle and buffaloes
HAEMORRHAGIC SEPTICAEMIA * global distribution |
acute septicaemia; high mortality (50-100%)
- most common 6-24 months Edema of the neck and high fever (remember: tonsillar carriers, stress/poor housing, exogenous infection- clinical cases) |
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Pasteurella multocida: cattle and buffaloes
Epizootic haemorrhagic septicaemia Diagnosis |
clinical and PM findings (sudden onset)
- direct blood smear to look for bipolar staining - culture blood and ID the sertypes B:2 and E:2 Giemsa stain of infected tissue showing characteristic bipolar staining of Pasteurella |
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Pasteurella multocida: cattle and buffaloes
Epizootic haemorrhagic septicaemia Control |
- slaughter affected animals
- treament: tetracyclines if catch early - vaccines: live attenuated P. multocida if endemic area |
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Pasteurella multocida: swine
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Atrophic rhinitis (needs coinfection with Bordetella brochiseptica for progressive disease)
- toxigenic strains (types A and D) - nasal cavity of pigs - disables some of innate immune system |
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Pasteurella multocida: fowls
green/yellow diarrhea |
Fowl cholera:
acute- septicaemia, chronic in survivors of acute infection (localised infections, swollen wattles, joints) transmitted: rats (bites), water, feed, or stress control: ABS in drinking water, good sanitation vaccines: live attenuated (CU- cholera universal) or heat killed emulsions of P. multocida serotypes |
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What are the key bacterial agents in Bovine respiratory disease?
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Mannheimia haemolytica and Pasteurella multocida
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mannheimia haemolytica
Describe diseases |
Pneumonia
Shipping Fever BRD (major impact on beef production worldwide) |
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Pasteurella multocida
Describe diseases |
-Enzootic pneumonia
- secondary invader (other pathogens also) |
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What is Shipping Fever?
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severe fibrinous pleuropneumonia
calves: 6 months- 2 years caused by stress (transportation) |
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Clinical signs of shipping fever
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sudden onset of fever, depression, nasal discharge
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In shipping fever- caused by M. haemolytica
- what is the major serotype? - what is the key virulence factor? - what is a mediator of pathology? |
A1 is major serotype
(A6 is only 25% of the case) -key virulence factor: Leukotoxin (ruminant leukocytes) mediator: host neutrophils |
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Are vaccines protective for Shipping Fever?
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~ 50% are protective for A1 serotype
- need to make sure the serotype you are using in the vaccine is the same serotype present. |
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Describe Pasteurellosis/Mannheimiosis in SHEEP
Mannheimia haemolytica Bibersteinia trehalosi |
M. haemolytica is carried in nasopharynx of healthy sheep but clinical syndromes include:
predisposing factors (viral infections) pneumonia in older sheep epticaemia in lambs <3 months old Bibersteinia trehalosi is carried in tonsils of healthy sheep but clinical syndromes include: precipitation factors (transportation) septicaemia of older lambs (5-12 months) |
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IN UK, M. haemolytica causes what in sheep that is as significant as S. Aureus from the mouth of lambs
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Mastitis
swollen, painful udder, bloody secretion, possible necrosis and death NO vaccine Systemic ABS (oxytet) |
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Louis Pasteur and Fowl Cholera!
how did he change how we think about vaccines? |
- cultured the fowl cholera virus
- GERM THEORY - recognized which inoculated chicks were resistant to infection - ORIGIN OF ATTENUATED VACCINES |
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Francisella tularensis
"Tularemia" |
epidemiology: arthropods (ticks and deerfly USA)
Animals: subclinical infections common clinical: fever, depression, septicaemia, tick infestation Bioterror: aerosol (respiratory pneumonia) |
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Haemophilus :
Histophilus somni (prev. Haemophilus somnus) |
flora of genital tract
Cattle: acute septicaemia, thromboembolic menigoencephalitis (TME) also involved in enzootic calf pneumonia and sporadic abortion Sheep: swelling of epididymitis in rams; |
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Haemophilus parasuis
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Grasser's disease in pigs
young 3-6 weeks old inflammation of serous membranes (polyseositis, arthritis, meningitis) |
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Avibacterium paragallinarum (prev. Haemophilus)
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Infectious coryza in birds
nasal and ocular discharge, drop in egg production |
