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RUSVM Bacteriology Gram Negatives > Moraxella > Flashcards

Moraxella Flashcards

1
Q

What family does the genus Moraxella belong to?

A

Family Moraxellaceae

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2
Q

Name the subgenera of Moraxella

A

Moraxella (rods) Branhamella (coccoid)

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3
Q

Moraxella Gram______? Shape?

A

Gram Negative, Pleomorphic -Rod short, pairs or chains

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4
Q

Moraxella Motile/Non-motile?

A

Non-motile

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5
Q

Moraxella Aerobic/Anaerobic?

A

Aerobic

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6
Q

Moraxella Catalase positive/negative?

A

Catalase positive Sometimes catalase variable

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7
Q

Moraxella Oxidase positive/Negative?

A

Oxidase positive

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8
Q

What two tests are Moraxella positive for?

A

Catalase & Oxidase positive

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9
Q

Is Moraxella proteolytic?

A

Yes.

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10
Q

What is the most important pathogen strain of Moraxella spp?

A

M. bovis

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11
Q

What disease does Moraxella bovis cause?

A

IBK - Infectious Bovine Keratoconjunctivitis

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12
Q

Describe IBK

A

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

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13
Q

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

A

IBK- Infectious Bovine Keratoconjunctivitis Caused by Moraxella bovis

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14
Q

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

A

Cytotoxin & Fimbriae

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15
Q

What are the virulence factors of Moraxella?

A

Adhesins Capsule Cell Wall Exotoxins

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16
Q

What do Moraxella’s Adhesins target?

A

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

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17
Q

What is different about the cell wall of Moraxella?

A

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

18
Q

Name the exotoxins of Moraxella

A

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

19
Q

Moraxella What is the role of Mbx?

A

Cytotoxin (hemolytic) Pore forming toxin

20
Q

Moraxella What type of cells does Mbx target?

A

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

21
Q

Does Moraxella show susceptibility or resistance to control?

A

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

22
Q

What aspects lead to Moraxella’s variability/diversity?

A

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

23
Q

Moraxella: Distribution / Reservoir

A

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

24
Q

Moraxella: Transmission methods

A

Direct & Indirect contact -Flying insects & airborne transmission

25
Q

Moraxella: Describe the Pathogenesis

A

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

26
Q

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

A
  • UV radiation - Flies, dust, woody pastures - IBR (Bovine Herpes Virus) - Adenovirus - Mycoplasma - Listeria - Nematodes
27
Q

What does IBK stand for and what pathogen causes it?

A

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

28
Q

Describe the pathology of IBK

A

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)

29
Q

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

A

“Pink Eye” or “New Forest diseases” -Mainly in young animals

30
Q

Describe the healing process for IBK

A

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

31
Q

What is the Morphological diagnosis (MDx) of IBK?

A

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

32
Q

These pictures are examples of what disease?

A

Infectious Bovine Keratoconjunctivitis (IBK)

33
Q

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

A

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

34
Q

What vitamin deficiency can predispose an animal to IBK?

A

Vitamin A deficiency

35
Q

What other pathogens can predispose an animal to IBK?

A

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

36
Q

Name a few ocular irritants from the environment

A

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

37
Q

Moraxella Immunological response

A

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

38
Q

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

A

Agent in smears of exudates -Immunofluorescence

39
Q

What tests are used for diagnosing Moraxella infections?

A

-Immunofluorescence -Culture -Biochemical analysis -Serological & PCR

40
Q

Moraxella Describe the proper culture to diagnose an infection

A

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

41
Q

Moraxella: Sugar (lactose) fermentation?

A

No. Non-fermenting.

42
Q

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

A

-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

RUSVM Bacteriology Gram Negatives (26 decks)

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