Gram Negative Non Enteric Bacteria Lawrence Flashcards
Family Pasturellacae
- Facultative anaerobic
- ferment glucose
- cytochrome oxidase positive
Letters designate
capsule type
Numbers designate
O polysaccharide
P. multocida
- multiple hosts
- opportunist pathogen
- common commensal in the URT of mammals and oral cavities of domestic animals(especially cats-common cause of bite wound infections in humans)
- not a commensal in birds, always associated with disease
Antigenic type
- A: fowl cholera; birds
- B: hemorrhagic septicemia (cattle)
- D: atrophic rhinitis (swine)
- E: hemorrhagic speticemia (cattle)
Capsular type A is most common capsular type ….
- isolated in disease cattle (BRD)
- porcine pneumonic pasteurellosis in swine
- snuffles in rabbits
Virulence Factors
-Capsular polysaccharide is required for virulence
-Type A capsule: hyaluronic acid
type D: heparin
type F: chondroitin
-P. multocida-type 4 fimbrae
-type D strains produce a thermolabile dermonecrotoxin
2 diseases where it acts as a primary pathogen
- hemorrhagic septicemia
- Fowl cholera
Hemorrhagic septicemia
-Cattle and water buffalo primarily effected
-Serotypes B:2 in asia and E:2 in africa
-Tropical and subtropics during rainy season, rain and high humidity facilitate transmission
-Transmission by ingestion or inhalation by direct contact via fomites
-Acute to peracute; no chronic cases
Salivation, dullness, respiratory distress, usually dies in 6-48 hours
-Morbidity rate depends on environmental conditions
-all ages affected but 6mo-2 year more affected
-case mortality is 100% unless treated early
Fowl cholera
- Serotypes A:1,3,4
- Highly contagious
- Turkeys tend to be more susceptible than chickens
- Carrier birds maintain pathogen and wild birds can be source
- 4 types of disease
- Peracute: 60% mortality without preceding signs
- Acute: depression, diarrhea, death in 2-3 days
- Sub acute form: respiratory. Pneumonia is especially common in turkeys
- Chronic form: localized lesions in the respiratory tract and conjunctiva; swollen wattels, joints, footpads
- Avian pathogenics are in normal flora but we don’t consider this part of normal flora
Atrophic rhinitis in swine
- opportunist
- caused by toxigenic P. multocida serotype D with Bordetella bronchiseptica in young pigs
- Ammonia and osteolysis of turbinates
Atrophic rhinitis disease
- a. Sneezing, tear-duct obstruction (tear-staining), serous to mucopurulent nasal discharge, epistaxis, lateral deviation or rostrocaudal compression of snout.
b. Less severe form: mild to moderate turbinate atrophy can be caused by B. bronchiseptica alone
c. B. bronchiseptica-toxigenic P. multocida cause severe progressive form
d. Overstocking and poor management can increase severity
e. Shortening of snout can result in difficulty eating, which can cause decreased production and feed conversion
f. Secondary pneumonia can result due to loss of turbinate defenses; typically fibrinous.
Respiratory infections
- usually serotype A
- Cattle: shipping fever or BRD (M. haemolytica
- Swine: non toxic serotype A, pneumonic pasteurellosis in grower-finisher pigs; fibrinous pneumonia
- Rabbits: snuffles, URT infection, can lead to fibrinous pneumonia and death
Other secondary infections
bite wound in humans
Identification
- nonmotile, nonhemolytic, no growth on MacConkey agar
- glucose fermenting, oxidase and catalase positive, indole positive
