19 – Pasteurellaceae Flashcards
Microbial characteristics
- Small gram-negative rods
- Facultative anaerobes
- Biocontainment level 2
Microbial characteristics: Pasteurella
- non-hemolytic
- strong INDOLE SMELL
- ***safety pin morphology on Gram-stain
Microbial characteristic: Mannheimia and Bibersteinia
- Hemolytic
Natural host or habitat
- Part of normal microbiota
o Oral cavity
o Respiratory and intestinal tract - *Pasteurella multocida can survive for a YEAR in the environment
- Other species: survive poorly outside the host
Pasteurella multocida: virulence factors
- PMT Toxin: cytotoxin/leukotoxin
- Capsular polysaccharide: prevents phagocytosis
Mannheima haemolytica: virulence factors
- LPS: stimulates cytokine release, microvascular necrosis
- Leukotoxin: kills ruminants leukocytes (SPECIFIC TO CATTLE)
What are the 3 general categories of disease?
- Respiratory
- Sepsis
- Trauma associated
Shipping fever
- Acute onset febrile illness
o Bronchopneumonia
o Fibrinous pleuropneumonia - *polymicrobial infections (including viruses)
o Bovine respiratory disease complex - High morbidity in affected herds
- High case fatality
Polymicrobial infection in shipping fever (3 species)
- P. multocida
- M. haemolytica
- B. trehalose
Shipping fever is precipitated by other insults
- Viral infection
- Poor air quality
- Long distance transport
- Weaning (enzootic pneumonia)
Shipping fever: what to do with affected animals and vaccinations
- Isolate and treat affected animals: antimicrobials (macrolide type)
- Vaccination: done on farm and can prevent disease in feedlot
o *challenge as farmer pays, feedlot benefits
Haemorrhagic septicemia (cattle): P. multocida
- Acute, rapidly fatal septicemia in cattle and buffalo
- Seasonal disease (monsoon rains in Asia)
- Caused by certain SEROTYPES of P. multocida
- *infected through direct contact with carriers/infected or fomites
o Carriers=maintain organism in herd - Not in Canada
Haemorrhagic septicemia characterized by
- Fever
- Dullness
- Discharges from nose
- Edematous swellings in gravity dependent sites (brisker and cervical region)
- Respiratory distress followed by death within 24hrs of first signs
Treatment of Haemorrhagic septicemia
- Antibiotic therapy possible in EARLY stages
- Vaccination possible
o Commercially prepared
o Bacterins
Atrophic rhinitis (pigs): P. multocida
- Caused by toxigenic P. multocida in association WITH Bordetella bronchiseptica
- Pathogenesis not completely understood
- *transmitted between animals DIRECTLY
o See outbreaks when purchasing new animals
What is the current pathogenesis model for atrophic rhinitis in pigs?
- Bordetella bronchiseptica causes damage, allowing P. multocida to proliferate
- Toxins produced by P. multocida cause epithelial hypoplasia, atrophy of mucous glands, osteolysis
- *ultimately results in atrophy of nasal turbinate’s and shrinking of snout
Atrophic rhinitis (pigs) is characterized by
- Excessive lacrimation, sneezing and epistaxis
- Younger the piglet=more severe signs
- Snout gradually atrophies
o Shrinks, wrinkles, may deviate laterally
Treatment of atrophic rhinitis (pigs) treatment
- No magic bullet
- *Improving management, vaccination, antimicrobials
P. multocida in rabbits causes a constellation of diseases (5)
- Rhinitis: ‘snuffles’
- Pneumonia
- Conjuctivitis (weepy eye)
- Otitis media/interna (head tilt)
- Abscesses
P. multocida (rabbits): ‘snuffles’
- VERY common cause of infections
- Highly contagious, transmitted through DIRECT contact
- Clinical signs vary with site of infection (mild upper respiratory tract through to sepsis)
- *healthy carriers are common: 30-90% of rabbits
P. multocida (birds): Avian Cholera
- Domestic and wild birds
o Wildlife reservoir=need to have good biosecurity - Acute or chronic
- Mortality can be very high (68%)
- Isoaltes from pigs and cats may be pathogenic for birds
P. multocida: Avian Cholera acute disease is characterized by
- fulminant septicemia
- often apparently sudden death within hours
P. multocida: Avian Cholera chronic disease
- follows acute disease when caused by LESS pathogenic stain
o localized infections and swellings of joints and wattle seen (chickens)
o dyspnea if respiratory involvement - *assumed to be source
What is happening in outbreak situations of P. multocida: Avian Cholera?
- Perpetuated by transmission from excretions from mouth
o Fluids get into water and infect others
P. multocida: Avian Cholera treatment
- Immediately notifiable disease in Canada
- Common in wildlife
- *elsewhere=antimicrobials will be employed
P. multocida (cats)
- Infections in cats associated with bites, licks and scratches
o Abscess in free roaming cats that fight
o Common cause of pyothorax in cats
o May play role in gigivostomatiis - *treatment relies on beta-lactam/inhibitor=amox+clavulanate
P. multocida (humans)
- Almost always CAT related
o Found in mouths of 90% of healthy cats - *cat bites=number ONE cause
- Can see non-traumatic cause
- *important to treat quickly
P. multocida (humans): non-traumatic cause
- Wound infections and cellulitis most common
- Bone and joint infections
- Respiratory tract infections
- Endocarditis
- CNS infections
Avibacterium paragallinarum (birds)
- Acute upper respiratory illness
- Transmitted by droplets or aerosols
- Production limiting disease (decreased egg production, increased carcass condemnations)
- *chorionic infected birds=source
- BIOSECURITY: all-in, all-out is important
Avibacterium paragallinarum (birds): characterized by
- Nasal discharge
- Sneezing
- Swelling of face
Specimens to collect
- Depends on site
o Viscera, blood
o Lungs
o Exudates
o Milk
o Ear tips
o Aspirates - *do NOT freeze
Lab ID
- Culture
o Easy on blood agar, biochemical ID or MALDI-TOF - Microscopy very useful (‘safety pins’ of P. multocida)
- Histopathology
Zoonotic/interspecies transmission
- P. multocida!
o Shared between species - Other genera=not common/important zoonoses
Treatment is highly dependent on
- Host species
- Site of infection
- National disease control strategies (ex. fowl cholera=stamped out)
- *beware of emerging resistance among shipping fever pathogens (particularly macrolides)
