SA Bacterial diseases

Question 1

Name and define 3 methods by which bacteria can exchange virulence factors and other DNA

Answer 1

• Transformation = plasmids or foreign DNA incorporated into genes • Transposition = DNA moves from one part of the genome to another • Conjugation = transfer of genes between adjacent bacteria via F-pili/sex pili • Transduction = bacteriophage (virus) transfers DNA between bacteria • Sporulation = transition to inactive (spore) state until conditions favor growth again

Question 2

Define resident, transient and nomad bacteria Which are able to multiple on normal skin?

Answer 2

RESIDENT BACTERIA • Resident: Bacteria capable of reproduction on healthy skin and form permanent population; can be reduced but not eliminated by antimicrobial techniques • Nomad: Bacteria capable of colonizing and reproducing for short periods. Capable of causing infection, can be eliminated by antimicrobials. • Transient: Bacteria acquired from environment; can be eliminated with hygienic measures; do not multiply on normal skin, can become involved as secondary invaders

Question 3

What organism is commonly cultured from puppy impetigo?

Answer 3

Coagulase positive Staph sp

Question 4

What bacteria would be most likely culture from a feline bite wound abscess?

Answer 4

Pasteurella multicoda

Question 5

Exudate from a draining nodule on a dog’s limb reveals small grains in the purulent debris. Name 3 ddx

Answer 5

Bacterial pseudomycetoma, actinomycosis, nocardiosis, fungal myceotoma, actinobacillosis

Question 6

You perform cytology on a non-healing wound from the fat pad of a cat. What is your tentative dx? What stains could be used to highlight your dx?

Answer 6

Rapidly growing/atypical/nontuberculous mycobacteral infection Ziehl-Neelson or Fite-Farco modifiaction staining

Question 7

What feature of mycobacteria causes the negative staining seen with DiffQuik stain?

Answer 7

High cell wall lipid content (known as mycolic acid)

Question 8

What is the causative organism of “cat scratch fever” in humans?

Answer 8

Bartonella henselae

Question 9

Actinomyces or Nocardia?

Is anaerobic and difficult to culture

Answer 9

Actinomyces

Question 10

Actinomyces or Nocardia?

Gram + and partially acid fast

Answer 10

Nocardia

Question 11

Actinomyces or Nocardia?

On histopath, pyogranuloma with grains present

Answer 11

Nocardia

Question 12

Actinomyces or Nocardia?

On cytology, long filamentous branching in loose aggregates or alone

Answer 12

Nocardia

Question 13

Actinomyces or Nocardia?

Clinically affect hunting dogs, and has a low mortality

Answer 13

Actinomyces

Question 14

Actinomyces or Nocardia?

Clinically, affect young dogs, hematogenously spread, and moderate to high mortality

Answer 14

Nocardia

Question 15

What species is the primary reservoir for Lancefield Group A Streptococcal species?

Answer 15

Humans

Question 16

Lancefield classification is for what bacteria?

Answer 16

Streptococcal bacterial

Based on cell wall carbohydrate differences

Question 17

What Lancefield group is Strep canis in?

Answer 17

Group G

Question 18

What bacteria is commonly responsible for toxic shock syndrome in dogs?

Answer 18

Strept canis

Question 19

Name the virulence factors for Toxic shock syndrome in dogs Strept canis infection

Answer 19

M protein, Streptolysin O