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RUSVM Bacteriology Gram Negatives > Moraxella > Flashcards

Flashcards in Moraxella Deck (42):
1

What family does the genus Moraxella belong to?

Family Moraxellaceae

2

Name the subgenera of Moraxella

Moraxella (rods) Branhamella (coccoid)

3

Moraxella Gram______? Shape?

Gram Negative, Pleomorphic -Rod short, pairs or chains

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4

Moraxella Motile/Non-motile?

Non-motile

5

Moraxella Aerobic/Anaerobic?

Aerobic

6

Moraxella Catalase positive/negative?

Catalase positive Sometimes catalase variable

7

Moraxella Oxidase positive/Negative?

Oxidase positive

8

What two tests are Moraxella positive for?

Catalase & Oxidase positive

9

Is Moraxella proteolytic?

Yes.

10

What is the most important pathogen strain of Moraxella spp?

M. bovis

11

What disease does Moraxella bovis cause?

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IBK - Infectious Bovine Keratoconjunctivitis

12

Describe IBK

Most common ocular disease of cattle -Highly infectious in beef cattle -Young susceptible, lack acquired immunity

13

What is the most common ocular disease of cattle, and name the causative agent

IBK- Infectious Bovine Keratoconjunctivitis Caused by Moraxella bovis

14

What are the two most important virulence factors of Moraxella bovis?

Cytotoxin & Fimbriae

15

What are the virulence factors of Moraxella?

Adhesins Capsule Cell Wall Exotoxins

16

What do Moraxella's Adhesins target?

Adhere to special niche/ target cells -Type 4 pilus (fimbriae) -Adhere to conjunctival and corneal epithelial cells

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17

What is different about the cell wall of Moraxella?

LPS without O-repeat unit (but still acts like LPS) Lipid A endotoxin & pro-inflammatory like normal

18

Name the exotoxins of Moraxella

RTX (repeats in toxin) Mbx (Moraxella bovis Toxin)

19

Moraxella What is the role of Mbx?

Cytotoxin (hemolytic) Pore forming toxin

20

Moraxella What type of cells does Mbx target?

Mbx (Moraxella bovis toxin) Specificity for: -Conjunctiva -Corneal epithelial cells -Neutrophils

21

Does Moraxella show susceptibility or resistance to control?

Moraxella is not that resistant to physical or chemical agents -Usually IS susceptible to antibiotics

22

What aspects lead to Moraxella's variability/diversity?

Pili (immunologically diverse, serological classification) Non-hemolytic variants are nonpathogenic

23

Moraxella: Distribution / Reservoir

Worldwide in bovine -Conjunctiva - Upper Respiratory Mucosa- Often without clinical outcomes

24

Moraxella: Transmission methods

Direct & Indirect contact -Flying insects & airborne transmission

25

Moraxella: Describe the Pathogenesis

Attachment at site & destruction of tissu (Pili, Mbx) --> Damage from Inflammation & bacterial growth (LPS, Neutrophils, Mbx)--> Environment & other pathogens collaborate in damage

26

What environmental agents and other pathogens collaborate with Moraxella to cause damage?

- UV radiation - Flies, dust, woody pastures - IBR (Bovine Herpes Virus) - Adenovirus - Mycoplasma - Listeria - Nematodes

27

What does IBK stand for and what pathogen causes it?

Infectious Bovine Keratoconjunctivitis -Moraxella bovis (M. bovis) -M. bovoculi has also been isolated

28

Describe the pathology of IBK

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Infectious Bovine Keratoconjuntivitis -Invasion of conjunctiva leads to edema & inflammation -Mild epiphora & corneal clouding -Severe edema, opacity, ulceration, uveal prolapse, panophthalmitis (inflammation of all coats/layers of eye)

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29

What are the nicknames for IBK? What age does it effect?

"Pink Eye" or "New Forest diseases" -Mainly in young animals

30

Describe the healing process for IBK

Healing of ulcers proceeds from the periphery and requires several weeks. -Central scarring persists for months

31

What is the Morphological diagnosis (MDx) of IBK?

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Chronic purulent and ulcerative keratitis -Mild conditions are self-limiting -Losses of vision, impaired animals do not forage & lose condition

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32

These pictures are examples of what disease?

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Infectious Bovine Keratoconjunctivitis (IBK)

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33

What aspects predispose an animal to an IBK or M. bovis infection?

-Young Bos indicus -Lack of eyelid pigmentation -Prominent eye placement -Nuisance flies -Ocular irritants of environment -Concurrent infections -Vitamin A deficiency

34

What vitamin deficiency can predispose an animal to IBK?

Vitamin A deficiency

35

What other pathogens can predispose an animal to IBK?

BHV-1 (Bovine rhinotracheitis-IBR) -Thelazia spp -Adenovirus -Mycoplasma bovoculi -Listeria monocytogenes

36

Name a few ocular irritants from the environment

Dust, tall grasses, UV light, cold or warm ambient temperatures

37

Moraxella Immunological response

Antibodies of all isotypes produced -Especially ____? -Experimental bacterins give some protection -Mainly against fimbrial proteins, Mbx

38

What samples are most useful to collect for Moraxella laboratory diagnosis tests?

Agent in smears of exudates -Immunofluorescence

39

What tests are used for diagnosing Moraxella infections?

-Immunofluorescence -Culture -Biochemical analysis -Serological & PCR

40

Moraxella Describe the proper culture to diagnose an infection

Lacrimal secretions in sterile water 35C in media with serum & blood ***Virulent M. bovis are fimbriate and hemolytic*** (they autoagglutinate in saline)

41

Moraxella: Sugar (lactose) fermentation?

No. Non-fermenting.

42

How would you treat and control a Moraxella bovis infection/outbreak?

-Affected animals in dark stall free of dust & flies -Topical corticosteroids reduce inflammation (controversial) -Topical & systemic antimicrobials (Long-acting tetracycline or florfenicol) -Fimbrial vaccines possible in future