Pasteurella & Mannheimia Flashcards
What are the 2 main structural characteristics of Pasteurella? What fermentation does it undergo?
- Gram-negative coccobacilli
- stains bipolar with Wright or Giemsa stain
ferment sugar without gas —> TSI turns orange
Where do all Pasteurella colonize? What is one exception?
respiratory tract
P. aerogenes —> GI tract
How does Pasteurella multocida grow on media? How does it respond to the indole test?
prefers blood agar, will NOT grow on MacConkey, and has a mousy odor
indole +
What colony types of Pasteurella multocida are encapsulated and virulent?
mucoid and smooth types
(there is also a rough type)
How does Pasteurella multocida infection compare to Haemophilus?
not as host-specific —> infections occur in many animals and humans
What specific diseases is Pasteurella multocida responsible for in poultry, cattle/sheep, swine, rabbits, cats/dogs, and humans? Does it have zoonotic potential?
POULTRY: fowl cholera
CATTLE/SHEEP: hemorrhagic septicemia, pneumonia (BRD), mastitis
SWINE: atrophic rhinitis, pneumonia
RABBITS: snuffles, pneumonia, septicemia
CATS/DOGS: local infections, bite wounds, respiratory infection
HUMANS: bite wounds, systemic infections
YES
How is Pasteurella multocida transmitted?
primarily carried in oral cavity and respiratory tract —> contact, direct inoculation (bite, scratches), aerosol, water (fowl cholera), endogenous
What is the 3 steps to the pathogenesis of Pasteurella multocida?
- part of the normal flora of the upper respiratory tract of man mammals
- presents as a pathogen in birds (NOT part of the flora), but those that recover act as a carrier and spread
- infections occur following stress
What causes fowl cholera? What is specifically not produced by this agent?
Pasteurella multocida types A1, A3, and A4, which contain hyaluronic acid in their capsule, a normal component of host tissue
A serotypes do not produce exotoxins
What animals are affected by fowl cholera? What are the common clinical signs? What does chronic infection lead to?
chickens, turkeys, ducks, geese, and other wild birds
- overwhelming bacteremia/septicemia
- depression
- inappetence
- diarrhea
- biofilm formation in the air sacs and mucous membranes, making them more difficult to clear
What is the relationship between Pasteurella multocida and birds?
frank pathogen, NOT an opportunistic pathogen
Fowl cholera:
- swollen wattles
- depression
- cellulitis
What is commonly seen within the swollen wattles of chickens with fowl cholera?
purulent material containing bacteria in biofilms
Fowl cholera, turkey:
- blood-stained mucus in mouth of septicemic tukey
- young, acute
Fowl cholera, septicemic form:
peritonitis
Fowl cholera, 10-week-old turkey:
- purulent pleuropneumonia
- pulmonary edema
Fowl cholera, turkey lungs:
- very consolidated pneumonia
- firm and not spongy, filled with bacteria and neutrophils
Fowl cholera, spongy bone:
- inflammation of air spaces within spongy bone of the skull
- purulent exudate
- swollen head syndrome
What is the predominant clinical sign of fowl cholera affecting the hock joint?
lameness
- purulent synovitis
What causes hemorrhagic septicemia? What animals are typically affected?
Pasteurella multocida B2 (Asia) and E2 (Africa)
exotic disease of cattle, buffalo, sheep, and goats
What are the 5 clinical signs of hemorrhagic septicemia? What causes disease?
- blood in cavities
- enteritis
- edema
- septicemia
- pneumonia
Pasteurella multocida B2 and E2 produce exotoxins
What causes Shipping Fever (bovine respiratory disease complex)? What animals are commonly affected?
Pasterurella multocida A strains
cattle, goats, sheep (opportunistic!)
What is Shipping Fever commonly secondary to? What are 4 common clinical signs?
stress or viral/mycoplasma infection
- cough
- fever
- nasal discharge
- bronchopneumonia
Shipping Fever (BRD complex) is a polymicrobial disease. What are 3 other possible agents?
- Mannheimia haemolytica
- Histophilus somni
- Mycoplasma bovis
- also: BHV-1, bovine diarrhea virus, bovine respiratory syncytial virus, parainfluenza-3
What is the main cause of atrophic rhinitis? How? What other pathogen does it typically present with?
Pasteurella multocida type D strains that produce dermonecrotoxin that causes bone resorption of turbinates and conchal bones and suppresses osteoid synthesis —> atrophied and deviated snout, difficulty breathing and eating
Bordetella bronchiseptica
What are the 3 major signs of atrophic rhinitis?
- atrophy and deviation of the snout in 3-7 week piglets
- destruction of the developing conchal bones of the nose
- inflammation may cause bloody and serous nasal discharge, sneezing, and eye discharge = “weeping”
What are 2 important characteristics of atrophic rhinitis? What is a secondary effect?
- polymicrobial
- biofilm formation
lacrimal duct blockage
What are 4 other swine diseases caused by Pasteurella multocida?
- pneumonia
- endocarditis
- arthritis
- placentitis
Where are lesions caused by Pasteurella multocida on the lungs commonly found?
dorsal surface
What does fibrous pericarditis caused by Pasteurella multocida in swine look like? What infection must it be differentiated from?
whitish adhesions of fibrous connective tissue between two layers of pericardium
Glasserella parasuis
What is snuffles? What causes it?
respiratory infection in rabbits characterized by mucopurulent discharge that occludes nares and conjunctiva, pneumonia with fever, ear infections, and septicemia
Pasteurella multocida
Snuffles, eye infection:
Snuffles, peritonitis:
followed by bacteremia
How is pasteurellosis typically transmitted to humans? What are 3 common clinical signs? What 3 species cause this?
bite wounds
- septicemia
- meningitis
- abscess formation
- P. canis
- P. dagmatis
- P. pneumotropica
What are 4 compromising factors of Pasteurella infection? In what situation is one of these factors not as important?
- stress (shipping)
- viral or mycoplasma infection
- bite wounds (puncture wound, harder to lavage bacteria)
- inclement weather
- environment is less important in fowl cholera and bovine hemorrhagic septicemia
What is the main virulence factor of Pasteurella?
CAPSULE - antiphagocytic, type A has hyaluronic acid and is nonimmunogenic
- TYPE A = cattle, swine, sheep, fowl
- TYPE D = atrophic rhinitis
- TYPE B and E = hemorrhagic septicemia
What is the main component of Pasteurella capsules?
carbohydrates (acidic)
- poorly immunogenic (T-independent Ag)
- protective antiphagocytic coat
- doesn’t activate complement
- nontoxic
- specific Ab overcomes protective function
How are Pasteurella strains characterized?
capsule and LOS
- A:1 = most important in fowl cholera
What is the function of fimbriae (pili) and siderophores for Pasteurella?
FIMBRIAE: attachement to host cells and biofilm formation
SIDEROPHORES: expressed under iron-limiting conditions to obtain iron from the host (multocidin) - less host-specific than iron-binding proteins
What are 3 toxins typically produced by Pasteurella and their functions?
- dermonecrotoxin - associated with type D strains; causes degenerative lesions in swine turbinates due to bone resorption (cytotoxic and osteolytic)
- hyaluronidase - aid in bloodstream dissemination
- neuraminidase - aids in colonization by removing sialic acid from the host tissue
What do Pasteurella produce when in a biofilm?
novel exopolysaccharide as a part of the matrix
What are 3 major aspects of immunity against Pasteurella multocida?
- natural host resistance and defenses
- antibodies against capsule (NOT A), LOS, toxins, and pili
- cellular immunity in chronic infections(?)
What are 2 cons to bacterins against Pasteurella? What is there a live vaccine available for? Inactivated vaccine?
- not effective against type A strains
- do not induce antibodies to toxin of type D strains (dead bacteria cannot make toxins!)
- fowl cholera —> may be too virulent
- Porcilis AR-T DF —> + adjuvant = fewer injection site reactions
What 3 characteristics of Mannheimia haemolytica differentiates it from Pasteurella multocida?
- grows poorly on MacConkey - tolerates it
- indole negative
- usually found only in the upper respiratory tract of cattle and sheep, limiting infection to these species
How did Mannheimia haemolytica used to be divided? What was recently discovered?
2 biotypes:
A = cannot ferment trehalose (most infections)
T = can ferment trehalose
T biotypes have been reclassified as Bibersteinia trehalosi
How does Mannheimia haemolytica affect cattle and sheep?
CATTLE: primary cause of shipping fever pneumonia; bacteremia
SHEEP: bacteremia, pneumonia, mastitis (bluebag)
What is the primary cause of shipping fever (BRDC) in cattle? What does disease development require?
Mannheimia haemolytica
stress - shipment or viral/mycoplasma infection
What are the 5 clinical signs of shipping fever (BRDC)? What are lesions primarily caused by?
- dyspnea
- fever
- cough
- nasal discharge
- fibrinous pneumonia at necropsy
RTX leukotoxin - lyses bovine white blood cells (weak on sheep WBCs)
What are common clinical presentations of shipping fever observable on a clinical exam?
- head and neck extension
- open-mouth breathing
- froth on lips due to difficulty breathing
Shipping fever (BRDC), cow:
- bilateral, mucopurulent nasal discharge
- Mannheimia haemolytica** +/- Pasteurella multocida
How do the lungs typically look with shipping fever?
- scattered, pale yellow abscesses
- hemorrhage and consolidation
Shipping fever (BRDC):
apical and cardiac lobes are dark red, slightly swollen, firm, and contain microabscesses
Shipping fever, pneumonia:
- fibrinous lobar pneumonia with red-brown consolidation and thickened interlobular septa
- bronchioles contain fibrinopurulent exudate
What are 2 other bovine/ovine diseases caused by Mannheimia haemolytica?
- hemorrhagic septicemia in nursing lambs (T biotypes) - B. trehalosi
- ovine enzootic pneumonia (A biotypes) - M. haemolytica
How does ovine respiratory disease caused by Mannheimia haemolytica compare to shipping fever in cattle? What are lesions like?
- clinical signs and stress factors are the same, except for shipment
- hemorrhagic with pleurisy and pericarditis
What causes ovine mastitis (bluebag)? How is it transmitted? What causes disease?
“Mannheimia” T strain - B. trehalosi
transmitted to teats by suckling lambs that carry the agent in the oral cavity (shift to M. haemolytica as sheep age)
leukotoxin causes necrosis and lack of blood flow to the udder
What are 2 other Mannheimia species that cause disease?
- M. granulomatis - roe deer, subclinical mastitis, abscesses, pneumonia
- M. varigena - meningitis, middle ear infection, milk, spleen
What are 3 virulence properties of Mannheimia haemolytica?
- capsule - antiphagocytic
- LPS - carbohydrate provides protection, lipid A is an endotoxin
- leukotoxin - RTX toxin specific for bovine WBCs and are able to lyse phagocytic cells to cause inflammation and direct damage to host tissue
What are 3 compromising factors of Mannheimia haemolytica infection?
- stress - shipping
- previous infection - bovine syncytial virus, parainfluenza virus, mycoplasma, herpes 1, Ehrlichia phagocytophilia (tick-borne fever)
- inclement weather
What is critical for immunity to Mannheimia haemolytica? What else can work?
neutralizing antibodies to leukotoxin
- antibody to capsule, LPS, and adherence factors (pili)
Why aren’t bacterins very effective against Mannheimia infection? What is most effective?
do not induce neutralizing antibodies to exotoxins
live vaccines —> concentrated culture supernatant containing capsule, leukotoxin, membranes, and an adjuvant
What samples can be used to isolate Pasteurella and Mannheimia? What are 5 ways to diagnose?
abscess material from a wound, transtracheal aspirate of the lungs, blood for bacteremia
- bipolar stain (G-)
- characteristic mousy odor if cultured
- indole +/-, oxidase test, orange on TSI media
- hemolysis on blood and (lack of) growth on MacConkey
- MALDI-TOF
(should be isolated at the predominant organism in high numbers)
How is Pasteurella and Mannheimia infections typically treated?
antibiotics - penicillins = drug of choice
- antibiotic resistance can occur, susceptibility test should be done
