Pasturellaceae

Question 1

General characteristics of Pasturellaceae

Answer 1

gram negative, non-motile, pleomorphic coccobacilli
aerobic/facultatively anaerobic
biochemically active
oxidase and catalase positive
many species have requirement for heamin, B vitamins or particular AAs
Many species contain extracellular toxins that are members of the repeat in structural toxin (RTX) family

Question 2

Cell wall of Pasturellaceae

Answer 2

Capsule: polysaccharides
LPS: major feature of gram negatives; antigenic and highly potent toxin
Outer membrane: structural, porins, reducible, scavenge nutrients
PG layer: hard skeleton- lends structure to bacilli/cocci
Inner membrane: lots of basic functions of cell–> classical 2 membrane structure.

Question 3

Hemophilus: general characteristics

Answer 3

Small to medium size gram negative, coccobacilli
non-motile
capable of fermenting sugar
will not grow on some lab media, CO2 is sometimes required
Require factor X (hemin) or V factor (nicotinamide adenine dinucleotide) or both.
Found on mucosal surfaces of animals and humans and are extremely host specific.
IRON is NECESSARY

Question 4

Species of hemophilus

Answer 4

H. paragallinarum- infectious coryza in fowl
H. parasuis- glasser’s disease/polyserositis in pigs
H. agni- septicemia in lambs
H. felis- vaginitis and pleurisy in cats
H. somni- thromboembolic meningoencephalitis (TEME), pneumonia, vaginitis in cows
H. somni- mastitis, epididymitis/orchitis, metritis, septicemia, meningoencephalitis, pneumonia and polyarthritis in sheep.

Question 5

Virulence factors of hemophilus

Answer 5

Capusle: H. parasuis and H. paragallinarium produce well-defined capsular polysacchardies- form protective coat around the bacteria and allows it to evade host defenses. tend to be sero-type specific antigen. H parasuis has 15 serotypes and H paragallinarium has 6.

Question 6

H. paragallinarum infection

Answer 6

fowl coryza: chickens affected most; turkeys and pigeons resistant.
Clinical signs: inflammation of the turbinates and sinus epithelium, disruption of the turbinates, acute air sacculitis
Infection usually more severe following viral or mycoplasma infection

Question 7

H. parasuis infection

Answer 7

carried in pig nasopharynx, may cause respiratory disease, most often manifests as a fibrinous, lobar pneumonia.
Glasser’s disease: fibrinous inflammation of the serous surfaces or joints; may affect pericardium, pleura, peritoneum, joints and in sever cases the meninges.
Signs: swollen joints and lameness, fever, pleuritis and possibly meningitis

Question 8

H. somni

Answer 8

spectrum of cattle diseases;
Thromboembolic meningoencephalitis (TEME): clinical signs include weakness, fever, staggering ,somnolence, dyspnea, paralysis and death
Repro failure may be a result of endometriosis, metritis or late abortion. mastitis and vaginitis may also occur.

Question 9

H. somni lesions

Answer 9

fibrinous meningitis with thrombosis and necrosis; pneumonia with pleuritis and arthritis

Question 10

Hemophilus virulence factors

Answer 10

LPS and lipooligosaccharides
LPS endotoxins of hemphilus differ from enterobacteriaceae in that they don’t have side chains
Endotoxin major role is to cause inflammation
CHO moiety predominant antigenic component of LPS or LOS
Exotoxins: H. somni produces a weak hemolysin
Proteases: destory mucosal IgA
Outer membrane proteins that bind to the Fc receptor of normal IgG block binding of specific IgG
Binding nucleotides on cell surface enhance survival in or killing of phagocytic cells.

Question 11

Host specificity of hemophilus

Answer 11

due to the abilit of a species to obtain iron from a single host.
under iron-limiting conditions, the bacteria that produce outer-membrane proteins are able to obtain iron from host transferrin; iron regulated outer membrane proteins (IROMPS)

Question 12

Diagnosis of hemophilus

Answer 12

isolation of bacteria from normally sterile sites or in pure culture to confirm isolate is pathogen and not part of normal flora.
Most isolates from animals require only NAD and will grow on commercial chocolate agar or on blood agar with streak of staph to provide NAD.

Question 13

Actinobacilli: General characteristics

Answer 13

Closely related to hemophilus
gram negative coccobacilli, pleomorphic, small, but long filaments may occur
fermentative without gas production
Some species will grown on Mac, but don’t require X or V factors
Colonies of most species will be sticky and difficult to remove from agar
Many species carry genes for the RTX hemolysis toxins (like hemophilus)

Question 14

Normal habitat of actinobacilli

Answer 14

respiratory, alimentary and urogenital tract

may occur as commensals or pathogens

Question 15

Actinobacilli oxygen requirements

Answer 15

facultative anaerobes

Question 16

Actinobacilli species- important

Answer 16

A. lignieresii- wooden tongue in cattle, skin abscess in sheep
Pigs (horses): A suis- neonatal septicemia, pneumonia, endocarditis
Pigs: A. pleuropneumoniae- pleuropneumonia
Horses: A. equuli- neonatal septicemia (sleepy foal disease)
Sheep: A. semini- epididymitis

Question 17

Virulence factors of actinobacilli

Answer 17

Capsules produced by A. pleuropneumoniae and A. capsulatus
All species contain LPS (endotoxin) with O side chains. Only LPS of A. pleuropneumoniae has been documented to contribute to lesions
Exotoxins: extracellular RTX toxins identified in A. pleuropneumonia, A. lignieresii, A. equuli, and A. suis.

Question 18

A. lignieresii- cultural characteristics

Answer 18

Slightly sticky, non-hemolytic colonies formed on blood agar
Pink colonies on MacConkey agar (ferment lactose)
In smears of pus or granules, clumps of organisms and club shaped bodies may be seen.

Question 19

A. lignieresii diseases

Answer 19

wooden tongue (hard abscesses in soft tissue) and rumenitis in cattle
Skin abscesses in sheep
Abscesses contain bacteria, sulphur granules.

Question 20

A. pleuropneumoniae- clinical signs and lesion presentation

Answer 20

cause of contagious pleuropneumonia of swine (absolutely specific). Lesions can be consolidated and congested, or hemorrhagic with necrosis.
Trembling, anorexia, dyspnea, fever and hemorrhage from nose and mouth
Animals may die with 24 hours

Question 21

Diagnosis of A. pleuropneumoniae

Answer 21

12 serotypes described based on capsular antigens but different serotypes predominate in different countries.
Colonies tend to be sticky and difficult to remove from plate
Some isolates may be smooth.
Requires V factor

Question 22

Pasturella- general characteristics

Answer 22

gram negative, short to medium sized coccobacilli

normal commensals of mucosal membranes of respiratory tract of mammals

Question 23

Pasturella-general O2 reqs.

Answer 23

most strains facultatively anaerobic

Question 24

Pasturella- do they ferment?

Answer 24

ferement glucose, gas isn’t produced

Question 25

P. multocida

Answer 25

mucoid colonies on culture, coccobacilli with capsules
Four main capsule types A, B, D and E
Type D produces dermonecrotoxin

Question 26

Fowl cholera

Answer 26

Capsular serogroup A and somatic serotypes 1,3 and 4 predominant in fowl cholera

Question 27

P. multocida diseases

Answer 27

septicemia, penumonia and rhinitis

Question 28

Manheimia hemolytica

Answer 28

13 serotypes recognized based on capsular antigens
Disease results usually following stress (transport, bad weather, castration or other predisposing factors)
Cattle: Type A1 causes shipping fever
Sheep: pneumona- caused by All serotypes

Question 29

M. hemolytica- toxin

Answer 29

produces a leukotoxin related to the RTX hemolysin of E. coli and exotoxins of A. pleuropneumoniae

Question 30

Bibersteinia trehalosi diseases

Answer 30

causes acute lamb septicemia in autumn and winter

Question 31

Pasturella virulence factors

Answer 31

Capsules: P. multocida, M. hemolytica and B. trehalosi are encapsulated: poorly immunogenic because of similarity to host hyaluronic acid
LPS: 1) protect organism from host defenses via CHO moiety 2) induce inflammation through lipid A
Exotoxins: type D and some type A strains of P. multocida produce a dermonecrotoxin–> important factor in pathogenesis of atropic rhinitis (destroys collagen)
M. hemolytica and B. trehalosi produce a labile leukotoxin–> knock out leukocytes, esp. lung macrophages.

Question 32

M. Hemolytica cultural characteristics

Answer 32

hemolysis- beta hemolysis on blood agar
fermentation of xylose
don’t produce indole
grow on mac agar- small pink colonies

Question 33

B. trehalosi cultural characteristics

Answer 33

hemolysis
no fermentation of xylose
no production of indole
no growth on Mac

Question 34

P. multocida

Answer 34

grows best on blood agar, characteristic odor
normal flora in nasopharynx
don't hemolyse
don't ferment xylose
do produce indole

Question 35

Pasturella on gram stain

Answer 35

bipolar organisms

Question 36

Important pasturella species and the diseases they cause

Answer 36

P. multocida capsule type A: pneumonia and rhinitis in all species
P. multocida capsules B and E: hemorrhagic septicemia in cattle
P. multocida capsules A and D: pneumonic pasturellosis in cattle
P. multocida D (toxigenic) in pigs: atropic rhinitis
P. multocida in pigs type A: pneumonia and/or septicemia
P.multocida gallicida: fowl cholera
P. gallinarum: fowl pneumonia
M. hemolytica: pneumonic pasturellosis in cattle, sheep and goats
Bibersteinia: systemic pasturellosis in sheep