Moraxella

Question 1

What family does the genus Moraxella belong to?

Answer 1

Family Moraxellaceae

Question 2

Name the subgenera of Moraxella

Answer 2

Moraxella (rods) Branhamella (coccoid)

Question 3

Moraxella Gram______? Shape?

Answer 3

Gram Negative, Pleomorphic -Rod short, pairs or chains

Question 4

Moraxella Motile/Non-motile?

Answer 4

Non-motile

Question 5

Moraxella Aerobic/Anaerobic?

Answer 5

Aerobic

Question 6

Moraxella Catalase positive/negative?

Answer 6

Catalase positive Sometimes catalase variable

Question 7

Moraxella Oxidase positive/Negative?

Answer 7

Oxidase positive

Question 8

What two tests are Moraxella positive for?

Answer 8

Catalase & Oxidase positive

Question 9

Is Moraxella proteolytic?

Answer 9

Yes.

Question 10

What is the most important pathogen strain of Moraxella spp?

Answer 10

M. bovis

Question 11

What disease does Moraxella bovis cause?

Answer 11

IBK - Infectious Bovine Keratoconjunctivitis

Question 12

Describe IBK

Answer 12

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

Question 13

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

Answer 13

IBK- Infectious Bovine Keratoconjunctivitis Caused by Moraxella bovis

Question 14

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

Answer 14

Cytotoxin & Fimbriae

Question 15

What are the virulence factors of Moraxella?

Answer 15

Adhesins Capsule Cell Wall Exotoxins

Question 16

What do Moraxella’s Adhesins target?

Answer 16

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

Question 17

What is different about the cell wall of Moraxella?

Answer 17

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

Question 18

Name the exotoxins of Moraxella

Answer 18

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

Question 19

Moraxella What is the role of Mbx?

Answer 19

Cytotoxin (hemolytic) Pore forming toxin

Question 20

Moraxella What type of cells does Mbx target?

Answer 20

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

Question 21

Does Moraxella show susceptibility or resistance to control?

Answer 21

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

Question 22

What aspects lead to Moraxella’s variability/diversity?

Answer 22

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

Question 23

Moraxella: Distribution / Reservoir

Answer 23

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

Question 24

Moraxella: Transmission methods

Answer 24

Direct & Indirect contact -Flying insects & airborne transmission

Question 25

Moraxella: Describe the Pathogenesis

Answer 25

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

Question 26

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

Answer 26

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

Question 27

What does IBK stand for and what pathogen causes it?

Answer 27

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

Question 28

Describe the pathology of IBK

Answer 28

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)

Question 29

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

Answer 29

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

Question 30

Describe the healing process for IBK

Answer 30

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

Question 31

What is the Morphological diagnosis (MDx) of IBK?

Answer 31

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

Question 32

These pictures are examples of what disease?

Answer 32

Infectious Bovine Keratoconjunctivitis (IBK)

Question 33

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

Answer 33

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

Question 34

What vitamin deficiency can predispose an animal to IBK?

Answer 34

Vitamin A deficiency

Question 35

What other pathogens can predispose an animal to IBK?

Answer 35

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

Question 36

Name a few ocular irritants from the environment

Answer 36

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

Question 37

Moraxella Immunological response

Answer 37

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

Question 38

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

Answer 38

Agent in smears of exudates -Immunofluorescence

Question 39

What tests are used for diagnosing Moraxella infections?

Answer 39

-Immunofluorescence -Culture -Biochemical analysis -Serological & PCR

Question 40

Moraxella Describe the proper culture to diagnose an infection

Answer 40

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

Question 41

Moraxella: Sugar (lactose) fermentation?

Answer 41

No. Non-fermenting.

Question 42

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

Answer 42

-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