2. Overview:
O Characterization of the genus Pasteurella
and the diseases they produce in animals
(P. multocida, and P. haemolytica)
O Characterization of the genus Pasteurella
(other species of Pasteurella)
O Characterization of the genus
Mannheima; and the bacterial diseases
they produce in animals
3. Introduction
O Species of the genera Pasteurella and
Mannheimia of the family Pasteurellaceae
are small gram-negative rods or coccobacilli.
O They are nonmotile, non-spore-forming,
facultatively anaerobic, oxidase positive, and
fermentative.
O These organisms grow best on media
supplemented with blood or serum
O Most are commensals on the mucous
membranes of the upper respiratory and
digestive tracts of domestic and wild animals.
Essential of Veterinary Bacteriology and Mycology Book
4. DISTRIBUTION AND
HABITAT
O Pasteurella and Mannheima organisms are
distributed worldwide.
O Most occur as commensals on the mucous
membrane of the upper respiratory and
digestive passages of animals. Thus, infections
are frequently endogenous.
O Exogenous infections also occur, particularly
during outbreaks of pasteurellosis in groups of
animals and pathogen virulence is enhanced
by animal-to-animal transmission.
Hagan’s Microbiology and Infectious diseases and
Concise Review of Veterinary Microbiology books
6. The Genus Pasteurella
O The genus Pasteurella belongs to the
family Pasteurellaceae, a complex group
of highly adapted parasitic organism that
includes the genera Actinobacillus and
Haemophilus.
O Pasteurella organism occur most
frequently as tiny, Gram-negative,
pleomorphic coccobacilli that stain in a
bipolar fashion in smears made from
specimens taken from lesions.
Hagan’s Microbiology and Infectious diseases book
7. The Genus Pasteurella
O They are nonmotile, usually oxidase- and
catalase-positive, and aerobic to
microaerophilic or facultatively anaerobic.
O Only 2 species of Pasteurella are of
importance in Veterinary medicine.
Pasteurella multocida
Pasteurella haemolytica
9. O P. multocida and P. haemolytica are important
pathogens of domestic and wild animals.
O P. multocida causes primary septicemias in
cattle and in domestic and wild birds and is
also an important opportunistic invader of the
respiratory tract of a variety of species.
O P. haemolytica is important both as primary
and opportunistic respiratory pathogen of
cattle and sheep and as a cause of
septicemia and mastitis in sheep.
10. O P. haemolytica and, to a lesser extent, P.
multocida are key constituents of shipping
fever complex in cattle.
O The other Pasteurella species are
relatively avirulent and are only
occassionally found in secondary
opportunistic invasions.
12. Pasteurella multocida
SYNONYM: Pasteurella gallicida
Morphology and Staining reactions:
• forms tiny ovoid rods shaped about 0.3
um wide by 0.4 to 0.8 um long
• in stained films obtained from infected
tissue, the ends of the rod are more
deeply stained than the central portion,
giving it a distinct bipolar appearance
• Wright’s stain or Giemsa stain is
recommended for demonstrating bipolar
staining
13. Pasteurella multocida
Cultural characteristic
• P. multocida grows very well on blood
agar
• It also grows on infusion agars; this
growth can be enhanced by the addition
of serum
• Colonies on blood agar are smooth,
greyish, non-haemolytic, buyrous, convex,
and about 1 to 2 mm in diameter, with a
subtle characteristic odour.
• Growth rarely occurs on MacConkey agar
14. Pasteurella multocida
Cultural characteristic
• Growth in infusion (broth) with serum
added is manifest by slight clouding and
a viscid sediment.
• P. multocida does not liquefy gelatin, but
does produce indole and reduce nitrates
to nitrites.
• Most strains produce hydrogen sulfide,
catalase, cyctochrome c, and ornithine
decarboxylase.
16. Pasteurella multocida
Biotypes
• Carter’s biotypes (1976) based on test for
hyaluronidase, decapsulation, acriflavine
flocculation, colonial iridescence, carbohydrate
fermentation, murine pathogenicity, and serum
protection.
1. Mucoid
2. Hemorrhagic septicemic
3. Porcine
4. Canine
5. feline
17. Pasteurella multocida
• three principal colonial variants:
1. Mucoid colonies
That are large, flowing, moderately virulent for mice,
and not typable by the usual serologic methods
2. Smooth or flourescent colonies
That are medium-sized, discrete, quite virulent for
mice, and typable
3. Rough or blue colonies
That are small, discrete, low in virulence for mice, and
autoagglutinable
18. Pasteurella multocida
Antigenic Nature
• Mucoid and smooth colonial variants carry the
specific soluble antigens associated with capsular
acidic polysaccharide.
• These type-specific antigens are the basis of
Robert’s (1947) and Carter’s (1955)
classifications. These are four Carter types: A, B,
D, and E.
19. Pasteurella multocida
Antigenic Nature
Types A, B, D, E, and F have
been identified on the basis
of differences in capsular
substances
(polysaccharides).
• Type A. Causes fowl
cholera, pneumonia, and
many other infections of
various animals.
• Type B. Causes epizootic
hemorrhagic septicemia in
Asia, the Middle East, and
southern Europe.
Concise Review of Veterinary
Microbiology book
20. Pasteurella multocida
• Type D. Recovered
relatively Infrequently
from various infections in
many animals, but
frequently from
pneumonia and atrophic
rhinitis in swine.
• Type E. Causes
hemorrhagic septicemia
in Africa.
• Type F. Recovered from
turkeys; its role in
disease is not yet clear.
21. Pasteurella multocida
Serological Classification
• P. multocida has also been
shown to carry somatic and O
antigens
• Capsular types may be
subdivided further into somatic
types (at least 16) on the basis
of serologic differences in
lipopolysaccharides (somatic
or 0 antigens).
• A serotype is designated by
the capsular type, followed by
the number representing the
somatic type
Hagan’s Microbiology
and Infectious diseases
book
23. Pasteurella multocida
Epizootiology
• P. multocida is normally maintained as a
commensal of the oropharynx of
mammals.
• Unlike mammals, though, healthy birds do
not carry the organism, and its presence
in birds is almost invariably associated
with acute or chronic disease.
24. Pasteurella multocida
Epizootiology
• The organism survives only briefly in the
environment but can survive in the carcasses
of animals for extended periods.
• Transmission between animals is usually by
air-borne droplets or by food or water
contamination.
• These modes of spread are of great
importance in the epizootiology of fowl cholera
and hemorrhagic septicemia of cattle and
buffaloes in the tropics.
25. Pasteurella multocida
Epizootiology
• outbreaks of respiratory disease in pigs and cattle
caused by P. multocida are apparently the result of
invasions by endogenous infections of the
nasopharynx.
• A variety of stressful situations such as shipment, viral
infection, bad weather, poor nutrition, and
overcrowding can impair the physical and
immunological defenses of animals and allow P.
multocida to multiply on the nasopharyngeal mucosa,
with subsequent penetration of the lower respiratory
tract.
26. Pasteurella multocida
Pathogenesis
• Primary viral and mycoplasmal infections
predispose animals to secondary invasions by P.
multocida by impairing alveolar macrophage
function and by damaging the mucociliary
clearance mechanism in the trachea and bronchi.
• The local inflammatory effect they cause leads to
increased fluidity of the mucus blanket, with
consequent sneezing and coughing and,
inevitably, formation of endogenous aerosols in
the respiratory tree.
27. Pasteurella multocida
Pathogenesis
• During inspiration the aerosols can result in
downward carriage of bacteria from the upper
parts of the tract.
• These are just some of the possible condition
that predispose animals to pneumonic
pasteurellosis.
28. Pasteurella multocida
Pathogenesis
• Stress or concurrent or antecedent viral infection
is of less importance in the pathogenesis of
hemorrhagic septicemia of cattle and sheep and
of fowl cholera.
• The strains of P. multocida involved in these
diseases are highly invasive by themselves and
the organisms therefore behave as primary
pathogens.
29. Pasteurella multocida
Pathogenesis of
Hemorrhagic septicemia
• Hemorrhagic septicemia is
a disease of cattle, buffalo,
goats, and sheep that
causes serious economic
losses in tropical and
subtropical zones of Asia
and Africa.
• Serotype B2 is responsible
for the disease found in Asia
• And serotype E2 is the
cause of the disease found
in Africa
30. Pasteurella multocida
Pathogenesis of Hemorrhagic septicemia
• The disease occurs during the rainy season.
• Outbreaks begin with the death of one or two
animals, which during their illness shed huge
numbers of P. multocida. These organisms are
transmitted directly or indirectly to nearby
animals.
• Very quickly an enzootic develops among
exposed susceptible animals. Affected animals
develop a high temperature (41 to 42C),
dysentery, edema , and, in advanced cases,
cyanosis of the mucous membranes. Mortality is
high.
31. Pasteurella multocida
Pathogenesis of Hemorrhagic septicemia
• Clinical signs:
Hemorrhages on serous surface
Blood-stained fluid in the thorax and abdomen
Enteritis
Edema in the subcutaneous tissues
32. Pasteurella multocida
Pathogenesis of Hemorrhagic septicemia
• Edema is characteristic of the less acute forms of the
disease.
• In subacute forms also, lesions can be confined to the
pectoral region and include fluid in the pleural and
pericardial sacs.
• Areas of pneumonia are present in the lungs together with
greatly thickened septa.
• Large numbers of P. multocida are present in tissues and
fluids.
• Some animals can be subclinically or chronically infected
and therefore are of importance in maintaining the infection
between enzootics.
• In carrier animals the organism is found in the tonsils an on
the pharyngeal mucosa.
33. Pasteurella multocida
Pathogenesis of Fowl
cholera
• Fowl cholera, the
pasteurellosis of birds,
affects chickens
principally, although ducks,
geese, turkeys, swans,
and other birds are
susceptible.
• Wild birds frequently
become infected and at a
times may be the source of
infection for domestic
flocks.
34. Pasteurella multocida
Pathogenesis of Fowl cholera
Transmission:
Is by the oral and respiratory routes
Entry can occur through the eye and also
through the skin abrasions (Bierer and
Derieux 1978)
• In many cases the disease is peracute
and is manifested by an overwhelming
bacteremia.
35. Pasteurella multocida
Pathogenesis of Fowl cholera
• Films prepared from blood or spleen pulp
show large numbers of minute, bipolar-
stained organisms.
• Outbreaks generally begin in a few birds
in apparently healthy flocks.
• The mortality varies from 10 – 75 percent.
36. Pasteurella multocida
Pathogenesis of Fowl cholera
• Clinical signs:
Depression
Sleepiness
Inappetence
Diarrhea
• Death can occur within a few hours, or
after 2 or 3 days. In some birds the course
is much longer.
37. Pasteurella multocida
Pathogenesis of Fowl cholera
• P.multocida is often associated with chronic
infections of the air sacs, accompanied by
accumulations of dry caseous material;
o with inflammatory processes in the wattles, especially
of male birds, which frequently cause necrosis
o And with infections on the mucous membranes of the
head, a condition commonly called colds.
• The organism is frequently found in the peritoneal
cavity of young laying birds mixed with yolk
material from ruptured ova.
38. Pasteurella multocida
Pathogenesis of Fowl
cholera
• Necrops findings:
few petechiae of the
heart
a slightly swollen
spleen
reddening of the
mucosa of the anterior
part of the intestine
39. Pasteurella multocida
Pathogenesis of Rabbit
septicemia
• Rabbit septicemia can
be very acute with
hardly any premonitory
signs.
• The causative agent
can be easily found in
films prepared from
blood or spleen pulp
after death of the
animal.
40. Pasteurella multocida
Pathogenesis of Rabbit septicemia
• A more common form of the disease is less
acute.
• The affected animals are clearly ill for some
days, during which they have fever, a
seropurulent nasal discharge, inappetence,
and, finally, difficult breathing.
• These animals suffer from the fibrinous
pneumonia, the greater part of the lungs often
being hepatized and the pleura covered with
fibrinous deposit.
41. Pasteurella multocida
Pathogenesis of Rabbit septicemia
• The lesions are minimal in rabbits with
peracute cases of p. multocida septicemia
and generally are limited to a few
petechiae on the heart and some serous
membranes.
• In rabbits with chronic cases the lesions
as a rule are limited to the organs of the
thorax.
42. Pasteurella multocida
Pathogenesis of
Snuffles in Rabbit
• Snuffles is the
common name
applied to a milder
respiratory infection
caused by P.
multocida.
• This disease initially
involves only the
upper respiratory
tract.
43. Pasteurella multocida
Pathogenesis of Snuffles in Rabbit
• Affected animals exhibit mucopurulent
exudate, which partially occludes the nares
and frequently the conjunctiva.
• The animals have difficulty in breathing.
• The noises made by a colony of affected
rabbits are characteristic and are responsible
for the common name of the disease.
• In some cases the rabbits develop fribinous
pneumonia and die.
Editor's Notes
Colonies of P. multocida are round, greyish, non-haemolytic and have a subtle characteristic odour.
Colonies of p. multocida grown on agar have dissociation patterns showing 3 principal colonial variants:
Type A is the most prevalent capsular type among P. multocida isolates from cattle, swine, poultry, and rabbits.
Type A is the most prevalent capsular type among P. multocida isolates from cattle, swine, poultry, and rabbits.
for example, serotype B:2 is the cause of hemorrhagic septicemia in many regions, and E:2 causes the same disease in Africa
Edema is characteristic of the less acute forms of the disease.
In subacute forms also, lesions can be confined to the pectoral region and include fluid in the pleural and pericardial sacs.
Areas of pneumonia are present in the lungs together with greatly thickened septa.
Large numbers of P. multocida are present in tissues and fluids.
Some animals can be subclinically or chronically infected and therefore are of importance in maintaining the infection between enzootics.
In carrier animals the organism is found in the tonsils an on the pharyngeal mucosa.
Fowl cholera, a widespread, contagious disease
of domestic and wild birds.
The daily mortality in a flock usually rises sharply, the peak normally being reached within a few days
within a few days
The affected birds generally exhibit signs of ……
The affected birds generally exhibit signs of ……
If such animals do not die within a few days, they become emaciated and usually are worthless afterward.
If such animals do not die within a few days, they become emaciated and usually are worthless afterward.
