Bacteriology 1&2

Question 1

Defense mechanisms of the eye (2)

Answer 1

1) Normal Flora
2) Tears and blinking

Question 2

How does normal flora help prevent eye infections (2)

Answer 2

1) Primarily Gram + bacteria present at low numbers
2) limit the ability of pathogens to attach & cause disease

Question 3

How do tears and blinking help prevent eye infections (2)

Answer 3

1) Rinse ocular surface
2) Contain antibacterial substances (IgA, Lysozyme and lactoferrin)

Question 4

Predisposing risk factors for extraocular infections (6)

Answer 4

1) most extra cellular infections are secondary
2) Trauma
3) Infections in adjacent structures
4) Drying of cornea
5) Immunosupression
6) Co-infection w/ other organs

Question 5

Predisposing risk factors for intraocular infections (3)

Answer 5

1) most are secondary
2) often ocular manifestations of systemic infections or disease
3) Some intraocular infections result from direct inoculation

Question 6

Mechanisms of damage of pathogens (4)

Answer 6

1) Adhere
2) Invade Tissues
3) Evade host defense mechanisms
4) cause host cell damage

Question 7

Extraocular Infections (7)

Answer 7

1) blepharitis
2) conjunctivitis
3) keratitis
4) keratoconjunctivitis
5) fungal infections
6) viral keratitis/conjunctivitis
7) viral corneal edema

Question 8

Causes for blepharitis (6)

Answer 8

1) Gram + cocci
2) S. pseudintermedius, B. hemolytic streptococci, S. canis, S. zooepidemicus
3) dermatophytes
4) cuterebra larvae
5) sarcoptes
6) demodex

Question 9

Cause of conjunctivitis (3)

Answer 9

1)Chlamydia felis
2) Mycoplasma spp.
3) Pasturella multocida

Question 10

Chlamydia felis (4)

Answer 10

1) Young cats
2) act alone or coinfection with feline herpes, mycoplasma
3) carrier animals source of infection

Question 11

Mycoplasma spp. (2)

Answer 11

1) cause of conjunctivitis & keratoconjunctivitis
2) act alone or in coinfection

Question 12

Species infected by Mycoplasma spp. that cause conjunctivitis & keratoconjunctivitis (5)

Answer 12

1) cats
2) sheep
3) goats
4) cattle
5) finches

Question 13

Cause of keratitis (3)

Answer 13

1) Gram + cocci
2) S. pseudintermedius, B. hemolytic streptococci, S. canis, S. zooepidemicus
3) Pseudomonas aeruginosa

Question 14

Pseudomonas aeruginosa (3)

Answer 14

1) poor pathogen
2) needs primary corneal damage to infect
3) may see melting ulcers
4) disease most associated is Equine keratitis

Question 15

Pathogenesis of Pseudomonas aeruginosa (5)

Answer 15

1) pili mediate attachment & colonization of damaged stroma
2) multiplication & invasion into corneal stroma
3) production of exotoxins
4) kill corneal epithelial cells
5) keratitis will exudate

Question 16

Clinical importance of melting ulcers

Answer 16

can cause rapid iris prolapse & globe collapse

Question 17

What additional testing should be done if Pseudomonas aeruginosa is cultured and why?

Answer 17

Susceptibility testing because it is not predictably susceptible & lots of intrinsic antimicrobial resistance

Question 18

Cause of keratoconjunctivitis (1)

Answer 18

Moraxella bovis

Question 19

Diseased caused by Moraxella bovis (1)

Answer 19

Bovine keratoconjunctivitis aka PINK EYE

Question 20

Moraxella bovis characteristics (3)

Answer 20

1) Gram - rods
2) coccobacilli
3) strict aerobes

Question 21

Conditions that predispose to Moraxella bovis (6)

Answer 21

1) breeds that lack eye pigment
2) young
3) bull calf
4) UV exposure
5) dry/dusty conditions
6) crowded conditions

Question 22

Transmission of Moraxella bovis (2)

Answer 22

1) infected carrier animals
2) mechanical transmission; flying insects

Question 23

Pathogenesis Moraxella bovis (3)

Answer 23

1) damage to the eye
2) fimbrie (pili) allow for attachment
3) Hemolysin

Question 24

What is the basis for the Moraxella bovis vaccine?

Answer 24

Fimbrie (pili)

Question 25

Potential sequelae to Bovine keratoconjunctivitis (2)

Answer 25

1) globe rupture
2) secondary infection: hypopyon

Question 26

Prevention/control for Bovine keratoconjunctivitis (5)

Answer 26

1) avoid predisposing factors
2) isolate affected animals
3) decrease stocking rates
4) add shade/fly control
5) VACCINATION**

Question 27

Cause for periocular infections

Answer 27

Dermatophytes (ringworm)

Question 28

Cause for surface ocular infections: Fungal keratitis (3)

Answer 28

1) fusarium
2) penicillum
3) aspergillus

Question 29

What species is fungal keratitis most common

Answer 29

Horses

Question 30

Transmission of fungal keratitis (1)

Answer 30

1) innoculation of organisms into traumatized corneal epithelium

Question 31

Virulence factors for fungal keratitis (2)

Answer 31

1) may inhibit corneal neovascularization
2) reduced neutrophil infiltration & cell-mediated phagocytosis & result in impeded healing

Question 32

Causes of Viral keratitis/conjunctivitis (2)

Answer 32

1) feline herpes
2) Distemper

Question 33

Feline herpes virus-1

Answer 33

1) contact with nasal, oral & conjunctival secretions of infected animals
2) short replication cycle
3) rapid cell to cell spread
4) tendency to induce cell lysis
5) persistence in sensory ganglia

Question 34

Sequele of feline herpes virus-1

Answer 34

symbepharon= adhesion of the conjunctiva to itself or to the cornea

Question 35

Canine distemper (3)

Answer 35

1) acute blephritis & conjunctivitis (1st clinical sign)
2) acute keratoconjunctivitis
3) intraocular & extraocular disease

Question 36

Causes of viral corneal edema

Answer 36

Canine adenovirus-1

Question 37

canine adenovirus-1 (5)

Answer 37

1) cause of infectious canine hepatitis
2) diffuse corneal edema “Blue eye”
3) deposit of immune complexes on endothelial cell of the eye
4) anterior uveitis
5) intraocular and extraocular disease

Question 38

Diseases that cause intraocular infections (5)

Answer 38

1) Leptospirra spp.
2) Gram - bacteria
3) Rickettsial infection
4) Viral infections
5) Fungal infections

Question 39

Leptospirra spp. (2)

Answer 39

1) anterior uveitis (ERU)
2) important in horses

Question 40

Gram - bacteria that can cause intraocular infections (4)

Answer 40

1) enterobacterales
2) histophilus somni
3) Borrelia burgdorferi
4) Brucella canis

Question 41

Causes of rickettsial eye infections (2)

Answer 41

1) Ehrlichia canis
2) Rickettsia rickettsii

Question 42

Causes of viral intraocular infections (3)

Answer 42

1) Feline coronavirus
2) Feline leukemia virus
3) Malignant catarrhal fever

Question 43

Feline coronavirus (3)

Answer 43

1) ocular manifestation predominantly in the “dry” form
2) bilateral granulomatous anterior uveitis & chorioretinitis
3) frequently see large keratic percipitates in anterior chamber

Question 44

Feline leukemia virus (3)

Answer 44

1) ocular manifestation is ocular lymphosarcoma
2) uveal tract common for metastasis

Question 45

Signs of feline leukemia virus (5)

Answer 45

1) mild uveitis
2) aqueous flare
3) keratitic precipitates
4) iris thickened- progression
5) glaucoma- progression

Question 46

Causes of fungal eye infections (3)

Answer 46

1) Histoplasmosis
2) Blastomycosis
3) Cryptococcosis

Question 47

Fungal eye infection characteristics (3)

Answer 47

1) severe systemic fungal infections have ocular signs
2) associated w/ posterior uveitis & anterior uveitis & chorioretinitis
3) ocular signs are the primary clinical manifestation of systemic mycosis

Question 48

Histoplasmosis (2)

Answer 48

1) Ohio, Missouri, Mississippi
2) can occur in cats; uncommon in dogs

Question 49

Blastomycosis (2)

Answer 49

1) mississippi/ohio & central atlantic states
2) ocular lesion in ~50% of dogs

Question 50

Ocular lesions of Blastomycosis (3)

Answer 50

1) chorioretinitis
2) anterior uveitis
3) endophthalmitis

Question 51

Cryptococcosis (2)

Answer 51

1) most common feline mycotic
2) chorioretinitis w/ granulomatous inflammation & retinal detachment; optic neuritis

Question 52

Parasitic intraocular infectious causes

Answer 52

Toxoplasma gondii

Question 53

Toxoplasma gondii (4)

Answer 53

1) most common lesion is chorioretinitis
2) multifocal dark gray infiltrates in the tepetal fundus
3) fluffy white infiltrates in the nontepetal fundus
5) +/- anterior uveitis