ACTINOBACILLUS

Question 1

Give the diagnostic methods for A. seminis.

Answer 1

• Difficult to identify due to its lack of biochemical activity
• Differentiation from B. ovis is based on morphology and modified Ziehl-Neelsen staining technique (mZ-N)
• Does not stain red in mZ-N staining technique
• Immunofluorescence technique used for diagnosis of epididymitis

Question 2

Identify the Actinobacillus sp. with the given data:

• Best grown on media enriched with blood or serum and incubated in an atmosphere of 20% CO2
• On 5% horse-blood tryptose agar: colonies are pinpoint to drop-like @ 24hrs; becomes enlarged and umbonate with transparent periphery and grayish center
• Non-hemolytic
• Does not grow on MAC
• Does not ferment CHO
• Does not produce catalase
• Does not reduce nitrates
• Produces **slight amounts of H2S **
• Negative results in: Oxidase, MRVP, indole, phosphatase, gelatinase, and Citrate utilization

Answer 2

A. seminis

Question 3

Actinobacillus ferments CHO. True or False?

Answer 3

True

Question 4

Actinobacillus produces indole. True or False?

Answer 4

False, only B-galactosidae

Question 5

Give the diagnostic methods for A. lignieresii.

Answer 5

• Gram-stained smears of sulfur granules reveal club-bearing rosettes containing masses of
• Gram-negative rods and cocci

Question 6

Actinobacillus can reduce nitrates to nitrites. True or False?

Answer 6

True

Question 7

Give the morphology of Actinobacillus spp.

Answer 7

• Gram-negative
• Non-motile
• Non-spore forming **rods or coccobacili
• Pleomorphic

Question 8

Give the diagnostic methods for A. pleuropneumoniae.

Answer 8

• Isolation on BAP
• Requirement for V factor
• presence of B-hemolysin

Question 9

Classify Actinobacillus based on their O2 requirement.

Answer 9

Facultatively anaerobic

Question 10

Identify the Actinobacillus sp. with the given data:

• Rod-shaped cells encased in small cheese-like granules in the pus of lesions
• Similar to “sulfur granules” of actinomycosis, but generally smaller
• Morphology depends on medium used:
  —- Fluid cultures: Diplococci and slender rods
  —- Solid media: Long curved forms in colonies
• Serophilic, little growth in most media unless serum or blood is present
• Rather strongly aerobic
• Primary cultures best grow when incubated in an atmosphere with 10% CO2
• In Serum agar: delicate nail-like growths along the length of stab made; surface colonies are bluish white
• Smooth, glistening, and convex
• Does not liquefy the medium
• Ferments: glucose, lactose, sucrose, maltose, raffinose, and mannitol
• Irregularly ferments xylose
• Produces indole in small amounts

Answer 10

A. lignieresii

Question 11

Actinobacillus is urease positive. True or False?

Answer 11

True

Question 12

Identify the Actinobacillus sp. with the given data:

• Grows rapidly on BAP and other enriched media
• Colonies are mucid and iridescent; 1-2 mm in diameter
• Produces a zone of Beta-hemolysis on sheep/calf-blood; enhanced by beta-toxin of S. aureus
• Hemolysin is extracellular

Answer 12

A. pleuropneumoniae

Question 13

This species causes actinobacillosis in cattle and sheep.

Answer 13

A. lignieresii

Question 14

Give the diagnostic methods for A. equuli.

Answer 14

• Blood, kidney lesions, synovial fluids, and cervical swabs from mares cultured on BAP

Question 15

This species causes foal septicemia.

Answer 15

A. equuli

Question 16

This species causes pneumonia in calves and seminal vesiculitis in bulls.

Answer 16

A. actinoides

Question 17

Give the immunities from A. lignieresii infection.

Answer 17

• Many normal cattle have specific agglutinins in their serum
• There maybe significant rise in the titer serum from affected cows
• Cell-mediated immunity is important due to granulomatous nature of lesions
• Formalinized bacterin reduces number of animals that relapse and prevents the occurrence of new cases.

Question 18

This species causes arthritis in rabbits.

Answer 18

A. capsulatus

Question 19

This species causes salpingitis and peritonitis in chickens.

Answer 19

A. salpingitidis

Question 20

This species causes septicemia and other infectious processes in pigs.

Answer 20

A. suis

Question 21

Give the immunities from A. suis infection.

Answer 21

• No commercial vaccine available

Question 22

Identify the Actinobacillus sp. with the given data:

• Colonies are moderately sticky and may adhere to agar surface
• In serum broth: produces viscous growth
• On horse-blood agar: narrow zones of alpha hemolysis
• On sheep-blood agar: wide zones of beta hemolysis
• May produce H2s
• Does not produce indole or urease
• Produces acid when grown with glucose, lactose, arabinose, mannitol, or salicin
• Hydrolyzes esculin

Answer 22

A. suis

Question 23

Give the diagnostic methods for A. suis.

Answer 23

• Specimens from tissues obtained at necropsy must be cultured on BAP and MAC; incubate at 37 °C for 1-3 days
• Sticky, hemolytic colonies
• Pink, lactose-fermenting colonies on MAC

Question 24

Give the immunities from A. seminis infection.

Answer 24

• Little is known about immune response
• Complement-fixing abs is present in serum
• Complement fixation detects about 75% of infected flocks

Question 25

Actinobacillus is non-fastidious. True or False?

Answer 25

False

Question 26

Identify the Actinobacillus sp. with the given data: * Short chains and filaments are often seen * Capsules have been described, but generally believed to be non-capsulated * Causes purulent infections of the joints and kidney abscesses in young foals, also found in adult horses * In foals, termed as “sleepy foal disease” * Grows readily in ordinary media * On agar plates: smooth, dry, and tough * On agar slants: growth is diffuse, grayish white, and highly mucoid * Slowly acidifies and sometimes coagulates litmus milk * Does not produce indole * Voges-Proskauer negative * Does not generate toxins * Usually non-hemolytic

Answer 26

A. equuli

Question 27

Give the immunities from A. equuli infection.

Answer 27

* Antiserum is ineffective in treating foals w/ equulosis * Vaccination of mares is an effective form of passive protection for foals

Question 28

This species causes contagious pleuropneumonia in pigs.

Answer 28

A. pleuropneumoniae

Question 29

This species causes epididymitis in young rams and purulent polyarthritis and gangrenous mastitis in sheep.

Answer 29

A. seminis

Question 30

Actinobacillus is always catalase and oxidase positive. True or False?

Answer 30

False, Catalase and oxidase variable (-/+)