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Bacteriology/ Mycology > Haemophilus, Actinobacillus, Pasteurella > Flashcards

Haemophilus, Actinobacillus, Pasteurella Flashcards

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1
Q

HAEMOPHILUS (were haemophilus)
–> Characteristics
* Gram- _______, ______
* weakly ______
* Originally based on whether requires _____ or blood _____. Now based on genetic relatedness.
* Normally X factor (hemin) or V factor (NAD) coenzyme in electron transport chain for
respiration. Found in UPR, urogenital tract; will not be found in environment.
* obligate parasite of host mucosal surfaces
* each species is host specific
* taxonomy is in state of flux

A

negative, coccobacillus, fermentative, blood, factors

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2
Q

Haemophilus” spp and their host
* Avibacterium (H.) paragallinarum
* Glaesserella (H). parasuis
* Histophilus (H.) somni

A

Used to be haemophillus, now this.

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3
Q
A

things in red = important

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4
Q

What disease do you think these pigs have?
* A. Atrophic rhinitis
* B. Swine cholera
* C. Glässer’s disease
* D. Erysipelas
* E. I don’t have a clue

A

C

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5
Q

What is (H.) parasuis?

A
  • specific for swine
  • requires V (NAD) factor only.
  • Nonhemolytic; does not produce an exotoxin
  • More than 15 serotypes may occur, based on capsule or lipooligosaccharide
    (LOS), or are untypable; usually a herd issue, which is why you want to know the serotypes.
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6
Q

Where do pigs with PRRS usually come from? What is the typical age of the pig? What can be seen clinically/ post mortem?

A

Pigs that have been infected with PRRS or are from SPF herds are particularly susceptible.
* Usually occurs in young pigs (important cause of nursery mortality; develop early on in development)
** fibrinous inflammation of serous surfaces (e.g. pleura or
joints)
“Purple ears are often a feature. Bacteria can readily be isolated from the blood and lesions at post-mortem examination. Chronic cases may be more difficult to
diagnose and may require P-M to look for joint and heart valve lesions.”

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7
Q

What can be seen in this image?

A

Glasser’s Disease (polyserositis)

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8
Q

What can be seen in this image?

A

Fibrin on paricardium and liver

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9
Q

What can be seen in this image?

A

Blood clot in trachea

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10
Q

What can be seen in this image?

A

Pericarditis;

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11
Q

Specific Diseases due to G. (H.) parasuis?

A
  • Respiratory Disease
  • Usually occurs in older pigs
    following previous infection
    (mycoplasma or virus)
  • Chronic pleurisy
  • Differential:
  • P. multocida, Bordetella,
    Actinobacillus spp., others
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12
Q
A
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13
Q

What are the virulence factors of G. (H.) parasuis ?

A

Virulence Properties
* Capsule
* Lipooligosaccharide
* Adherence factors
* Membrane proteins, no known exotoxins

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14
Q

What are the Adherence Factors of G.(H) parasuis?

A
  • required to colonize the host
  • bacteria attach to mucosal epithelial cells
  • Usually mediated through pili, LOS, or membrane proteins
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15
Q

What is important about the haemophilus species in terms of bacterial composition?

A

Lipooligosaccharide
There are no O side chains (polysaccharide) in the LPS of Haemophilus species examined, and therefore it can be called an LOS
* The Lipid A still has endotoxic properties
** Causes inflammation
* Core oligosaccharide is antigenic

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16
Q

What are the Compromising Factors?
* Viral Infection: associated with respiratory disease
* Stress: associated with Glasser’s disease, but not required as
newborn pigs are already compromised
The disease is predominately the result of HOST INFLAMMATION-trying to remove a pathogen it cannot

A
  • Viral Infection: associated with respiratory disease
  • Stress: associated with Glasser’s disease, but not required as
    newborn pigs are already compromised
    The disease is predominately the result of HOST INFLAMMATION-trying to remove a pathogen it cannot
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17
Q

How is Immunity to G. (H.) parasuis formed?

A
  • Protection is usually mediated by antibodies to capsule; however,
    there are at least 15 capsule types
  • Protective antibodies may also be made to LOS, membrane proteins,
    and other somatic antigens.
  • Humoral immunity most important
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18
Q

What is the Vaccination, treatment and prevention of G. (H) parasuis ?

A

Make sure to get correct serotype.
Don’t necessarily need to be long lasting in the case of Glaccier’s disease
Vaccination, treatment and prevention
*Bacterins are effective against homologous serotype (and somewhat against
others), but may not be long lasting
* Attenuated live vaccine also available and effective
* Antimicrobials
* Intentional exposure at 3-5 days of age with low dose of less virulent
serotypes (RISKY)
* Protection also through maternal antibodies

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19
Q

What is Avibacterium (H). paragallinarum?

A

Avibacterium (H). paragallinarum
* Specific for avian species
* Requires V factor only
* Nonhemolytic

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20
Q
A
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21
Q

What diseases are Specific due to A. paragallinarum?

A

Fowl Coryza (acute rhinitis)
* inflammation of turbinates and sinus epithelium
* air sacculitis
* primarily a disease of chickens

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23
Q

What is seen here?

Study These Flashcards
A

Depressed, discharge near beak, painful, hunched over

24
Q

What is seen here?

Study These Flashcards
A

High morbidity, but not
mortality

25
What is seen here?
Inflammation of air sacs
26
What is seen here?
Inflammation, pus
27
What are the Virulence Properties of A. paragallinarum?
* Capsule * Lipooligosaccharide * Adherence factors * Membrane proteins?, exotoxins not recognized
28
What are the Compromising Factors of A paragallinarum?
* Viral or mycoplasma infection * Stress Again, disease is predominately due to host inflammation
29
How is Immunity to A. paragallinarum formed?
* Protection is usually mediated by antibodies to capsule * Protective antibodies may also be made to LOS, membrane proteins, and other somatic antigens. * Humoral immunity most important
30
What is important about Vaccination for A. paragallinarum?
* Bacterins (to serotypes A, B, and C) are effective * Designed to raise antibody to cell components * Antibodies to capsule are protective, but only against 1 serotype - purified capsules nonimmunogenic * Other serotypes may be present
31
32
* What is the most likely etiologic agent of this outbreak? * A. Pasteurella multocida * B. Mannheimia haemolytica * C. Histophilus somni * D. A virus * E. Any or all of the above
C
33
What is Histophilus somni?
* Includes Haemophilus somnus, H. agni, and Histophilus ovis * Specific for bovines and sheep * Requires neither X or V factor, but does **require blood and CO2** * Most have yellow pigment * Weakly hemolytic or nonhemolytic * **Colonies are yellow **when picked up with a white swab
34
What is seen here?
Need CO2 and yellow = key characteristic
35
What is the normal habitat of histophilus somni?
* Normal habitat is the ruminant genital and respiratory tracts * Disseminates via the bloodstream and localizes at other sites (brain, heart, joints, etc.) * Reasons for dissemination are not clear * Probably due to inflammation of endothelium (**vasculitis** is a hallmark of this pathogen) * Stress and viral infection are required; primarily a feedlot disease; rarily see it in cattle that live out on passure
36
What specific diseases are due to H. somni?
Specific diseases due to H. somni * First disease documented by this organism = TME (thrombotic meningoencephalitis) * ****Pneumonia (BRDC or shipping fever) ***** Myocarditis (biofilm formation) * Reproductive failure (abortion, infertility) * Arthritis * Bacteremia * Others
37
What is seen here?
TME Eyes drooping, inflammed (key of TME) Laying down; unwilling to get up
38
What is seen here?
Pneumonia
39
What is seen here?
Myocarditis Acute, necrotizing myocarditis; bacteria are in biofilm-like aggregates and adherent to venous endothelium, with fibrin and neutrophils
40
How is the Biofilm formed for H. Somni?
* H. somni forms a biofilm under most growth conditions and in host tissues. When in a biofilm, bacteria are **more resistant to antibiotics and host defenses**, but induce **less inflammation**
41
What is seen here?
Filaments, fibirn material polysa, protein, extracelluar dNA = components of biofilm.
42
What are the Virulence Properties of H. somni?
* Endotoxin (Lipooligosaccharide) Phase variation of lipooligosaccharide in vivo * Antigenic epitopes change and enable bacteria to evade host immunity; some are identical to host oligosaccharides * In the host, the bacteria take up sialic acid and decorate their surface with sialic acid Their whole defense mechanism is to hide from the host.
43
What is seen here?
short chains; can phase vary. Can resist host defenses; host makes antibodey repsonse to Lipo, organisms cleared and those that have changed their oligo now persist.
44
What are some additional Virulence factors for H. Somni?
Produce a very large protein: IgG Fc receptors (immunoglobulin binding protein [IbpA] on bacterium * bacterium binds Fc region of IgG, protecting the bacterium from host defenses (fibrillar network of IbpA) **** (there is a toxic fic motif in IbpA) ****Survives within phagocytic cells** by inhibiting phagosome-lysosome fusion * LOS causes apoptosis of endothelial cells, leading to vasculitis * Adherence factors-many
45
Region within gene of immmunogobluni binding protein that produces a Toxin/Exotoxin (has not be categorized yet) H. somni produces a cytotoxin as part of a motif of the IgG binding protein A. This motif has been shown to be toxic for bovine endothelial cells and macrophages.
Causes vasculities, enabling bacteria to penetrate host BBB ad enter blood stream.
46
What is seen in this image?
Third image on right = cell that does produce binding protein.
47
What are the Compromising Factors of H. Somni?
* Infection with virulent, as opposed to “commensal”, isolates * Stress * Previous infection Disease is due to host inflammation
48
How is Immunity to H. somni developed?
* Antibodies to the bacterium are normally present in animals and should be protective, but no direct evidence for this yet; can survive in phagocytic cells *** Virulence is largely due to avoiding the host immune response * Protective components not well defined, and likely require cellular immunity * Antibodies to fic motif protective in passive immunity studies
49
What are the vaccination strategies for H. Somni?
Bacterins are limited in effectiveness due to phase variation and IgG binding proteins; best against TME * An effective vaccine against BRD has not yet been developed. Need an intelligen vaccine that recognizes antigens expressed in the host.
50
What is the Host specificity of H. Somni?
* Host specificity is mediated by adherence and **iron acquisition** * Host-specific bacteria obtain iron from host transferrin. Species that can only utilize transferrin of one host cannot infect other animals.
51
How do you Diagnose Haemophilus spp.?
*Culture: * Need to isolate from sterile site or in pure culture – **chocolate agar** = blood agar heated to 80 degrees * Most isolates from animals require NAD only **(blood for H. somni)** * Some species may require CO 2 (H. somni, some G. (H.) parasuis)
52
Is serology used to diagnose Hemophilus species i? What is the most common tests? What are not very sensitive?
Serology (not usually used): * Complement fixation test most common * Slide or tube agglutination tests easy to do, but are not very sensitive or specific * others that are more sensitive and specific include ELISA. * Outer membrane protein preps or exopolysaccharide
53
What are the treatment options for hemophilus spp?
* Susceptible to most antibiotics * Use least expensive and most appropriate drugs * Antimicrobial resistance can occur; may need susceptibility test
54
Summary * A. paragallinarum - Fowl coryza *Birds only * G. (H.) parasuis - Glasser’s disease, pneumonia, septicemia *PIGS ONLY * H. somni - TME, pneumonia, myocarditis, abortion, arthritis *BOVINES, and occasionally sheep, ONLY

Bacteriology/ Mycology (19 decks)

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