Pasteurellaceae Flashcards
What kind of bacterial characteristics do the family Pasteurellacea have?
- Gram Negative
- non motile
- pleomorphic cocco bacilli
- Aerobic/ Facultative anaerobic
- Oxidase/ catalase positive
- Many species contain extracellular toxins that are members of the Repeat in Structural Toxin family (RTX)
Haemophilus:
Small, Gram Negative rods
Coccobacillary shaped
Facultative anerobes
Fastidious nature-will only grow on certain laboratory media. (NO growth on macconkey) Require extra heme products and CO2.
Blood loving based on their requirements of growth factors X factor (hemin) or V factor (nicotinamide adenine dinucleotide**)(NAD)– Feeds into idea that they are fastidious and need these factors to grow. **
Found on host mucosal surfaces and are **very host specific. **
Haemophilus Virulence factors:
Capsule:
LPS/ LOS:
Host specificity
Capsule:
H. parasuis & H. paragallinarum (Pig/ Poultry)
Capsule forms a protective coating around the bacterium and allows it to evade host defences (IgG)
Capsule tends to be serotype specific antigen.
LPS/ LOS:
The LPS endotoxins of Haemophilus spp. differ from those of the Enterobacteriaceae in that they do not have O side chains.
The carbohydrate moeity is the predonminant antigenic component of the LPS/LOS.
**Host specificity determined by: **
the ability of a species to obtain iron only from a single host.
Under iron limiting conditions the bacteria produce outer membrane proteins that are able to obtain iron from the host transferrin molecules.
Iron regulated outer membrane proteins.
H. paragallinarum:
What species affected?
What disease does it cause?
What are the clinical symptoms?
- Infectous coryza
- chickens are primarily infected. Turkeys and pigeons are resitant to infection.
- Inflammation of the turbinates and sinus epithelium, acute air sacculitis.
- Opportunisitic pathogens therefore they are more sensitive/ infectous following viral/ stress/ or mycoplasam infections.
- When combined with mycoplasma infection can cause severe pneumonia.
H. parasuis:
What species affected and what diseases does it cause?
Pigs.
carried in the pig nasopharynx.
may cause respiratory disease
Respiratory diseases most often manitfsta as a fibrinous lobar pneumonia.
Glasser’s Disease: fibrinous inflammation of the serous surfaces or joints.
Clinical signs: Swollen joints and lameness, fever, pleuritis, and possibly meningitis.
What is Glasser’s disease, what are the clinical symptoms, and what bacteria causes it?
Glasser’s Disease: fibrinous inflammation of the serous surfaces or joints.
Clinical signs: Swollen joints and lameness, fever, pleuritis, and possibly meningitis.
H. somni:
What species does the affect?
What diseases does it cause?
spectrum of diseases in cattle.
TEME (thromboembolic meningoencephalitis)
Clinical signs: weakness, fever, starggering, somnolence, dyspnea, paralysis, death.
Lesions consists of a fibrous meningitis, with thrombosis and necrosis
pneumonia with pleuritis and arthritis.
Actinobacilli: General Characteristics:
- Similar to Haemophilus but contains long filaments.
- Some species will grow on MacConkey.
- Unlike Haemophilus, **do not require X or V factors. **
- Normal habitat of these species is the respiratory, alimentary, or urogenital tract.
- May act as commensal or pathogenic.
- Many species carry genes for RTX hemolysis toxins.
- Gram negative facultative anaerobes.
Actinobacillus Virulence Factors:
Capsules?
LPS?
Exotoxins?
Capsules:
Only produced by A. pleuropneumoniae (pigs) & A. capsulatus
**LPS: **
All species contain LPS (endotoxin) with O side chains (Hemophilus has no O side chain)
Only the LPS of A. pleuropneumoniae contributes to lesions.
Exotoxins:
Extracellular RTX toxins identified and characterized in A. pleuropneumoniae although A. lignieresii, a. equuli, and A. suis have them as well but role in disease has not been defined.
A. lignieresii:
Slightly sticky, Non hemolytics colonies formed on blood agar.
Pink colonies on MacConkey (lactose fermenting)
Causes wooden tongue and ruminitis in cattle, skin abscesses in sheep.
A. pleuropneumoniae
Species?
Cause?
Symptoms?
- Cuase of contagious pleuropneumonia of swine and **ABSOLUTELY specific for swine. **
- grossly, **fibrinous pleuritis and necrotizing pneumonia. **
- Lesions may consist of consolidation, or congestion, or maybe hemorrhagic with necrosis.
- Clinical symptoms: trembling, anorexia, fever, dyspnea, and hemorrhaging from the nose and mouth.
Actinobacilli Diagnosis:
Colonies tend ot be sticky and difficult to remove from the plate.
A. pleuropneumoniae requires V factor and can be isolated on chocolate agar or on blood agar with a streak of staphylococcus.
A. lignieresii needs to be cultured on blood agar in CO2.
Gram stain of sulfur granules will reveal the bacteria mixed with host debris.
Pasteurella: General Characteristics:
Gram Negative short to medium sized coccobacilli
Facultative anaerobes
**Bi polar staining- GIEMSTA STAIN (BRUCELLA ALSO) **
Ferment glucose, gas is not produced.
Only M. hemolytica is Beta hemolytic on blood agar.
M. Hemolytica and P. aerogenes will grow somewhat on MacConkey (lactose fermenting)
Commensals of mucosal membranes of the respiratory tract of mammals.
Pasteurellae: Virulence factors:
Capsules:
P. multocida, M. hemolytica, B. trehalosi are encapuslated.
Capsules are poorly immunogenic because of the presence of hyaluronic acid which is a host antigen.
**LPS: **
Plays a role by two mechanisms:
- protect the organims from host defenses through the carbohydrate moeity.
- induce inflammtaion through the Lipid A component.
Exotoxins:
A dermonecrotoxin is produced by type D and some type A strains of P. multocida and is considered an important virulence factor in the pathogenesis of atrophic rhinitis.
M. hemolytica and B. trehalosi produce a labile leukotoxin (RTX toxin) important in the pathogenesis of shipping fever and respiratory disease.
P. multocida:
Species?
What kind of diseases does it cause?
Pigs
Mucoid colonies
coccobacilli with capsules
four main caspule types A,B,D,E
Capuslar serogroup A and somatic serotypes 1,3, and 4 are predominant in fowl cholera.
Type D produces dermonecrotoxin.
Causes a range of diseases: septicemia, penuomnia, atrophic rhinitis.
