NON-BRANCHING, CATALASE NEGATIVE, GRAM-POSITIVE BACILLI (ERYSIPELOTHRIX, LACTOBACILLUS, AND SIMILAR ORGANISMS)

Question 1

General Characteristics sa ERYSIPELOTHRIX, LACTOBACILLUS, AND SIMILAR ORGANISMS

Answer 1

• Catalase-negative
• Non-spore-forming
• Gram-positive rods
• Some may exhibit rudimentary
  branching

Question 2

What is the only human pathogen in the Erysipelothrix genus?

Answer 2

E. rhusiopathiae.

Question 3

-a pleomorphic, gram-positive bacillus that
-often forms long filaments,
-is catalase-negative,
-forms hydrogen sulfide,
- is non-motile but produces a characteristic “bottle brush” extension laterally from the streak line in soft gelatin agar.

Answer 3

E. rhusiopathiae

Question 4

What is Arcanobacterium haemolyticum and where is it commonly found?

Answer 4

-is recovered from clinical specimens
-and is a normal inhabitant of the mucosal membranes of cattle, sheep, dogs, cats, and pigs.

Question 4

Where is E. rhusiopathiae commonly found and how is it transmitted?

Answer 4

E. rhusiopathiae is found in vertebrate and invertebrate animals and is transmitted via direct contact or ingestion of infected water or meat.

Question 5

-Previously classified as Arcanobacterium spp. -are irregular, gram-positive rods, CAMP negative

Answer 5

Trueperella spp

Question 6

Beneficial to the human host in immunocompetent individuals

Answer 6

Lactobacillus spp.

Question 7

What are some beneficial Lactobacillus spp. isolates for immunocompetent individuals?

Answer 7

-L. acidophilus,
-L. casei,
-L. fermentum,
-L. gasseri,
-L. plantarum,
-L. rhamnosus,
- L. ultunensis.

Question 8

-Only specie in the genus
-has a thinner peptidoglycan layer than other gram-positive organisms, appearing as thin, gram-positive rods or coccobacilli.

Answer 8

Gardnerella vaginalis

Question 9

are important for maintaining the proper pH balance in vaginal secretions.

Answer 9

Lactobacillus spp.

Question 10

Lactobacillus spp. are frequently associated with?

Answer 10

dental caries.

Question 11

Which occupations are at higher risk for Erysipelothrix infections?

Answer 11

-fish handlers,
-farmers,
-slaughterhouse workers,
-food preparation workers,
-and veterinarians

Question 12

Erysipelothrix infections typically occur due?

Answer 12

to puncture wounds or skin abrasions.

Question 13

What are the possible manifestations of Erysipelothrix infections?

Answer 13

-localized skin infections or cellulitis (erysipeloid),
-diffuse cutaneous infection with systemic infections,
- or bacteremia.

Question 14

What human infection is primarily associated with Arcanobacterium haemolyticum?

Answer 14

pharyngitis

Question 15

Trueperella bernardiae can be recovered from ?

Answer 15

blood, abscesses, urinary tract, joints, eyes, and wounds, and is associated with necrotizing fasciitis.

Question 16

In what environments is Trueperella pyogenes typically found, and what infections does it cause?

Answer 16

found in rural environments and has been identified in abscesses, wounds, and blood infections

Question 17

delicate, curved, gram-positive rods with pointed ends and occasional rudimentary branching.

Answer 17

Arcanobacterium spp

Question 18

are highly pleomorphic, appearing as long chaining rods, coccobacilli, and spiral forms.

Answer 18

Lactobacillus spp

Question 19

stains as both short rods and long filaments.

Answer 19

Erysipelothrix rhusiopathiae

Question 20

small, pleomorphic, gram-variable or gram-negative coccobacilli and short rods.

Answer 20

Gardnerella

Question 21

Clue cells are?

Answer 21

large, squamous epithelial cells with numerous attached rods.

Question 22

What happens when 10% KOH is added to a discharge sample?

Answer 22

It produces a fishy odor.

Question 23

What are the media of choice for cultivating Gardnerella?

Answer 23

-5% sheep blood and chocolate agars

-Columbia colistin-nalidixic acid (CNA) agar

-Human blood bilayer Tween agar (HBT) for isolating G. vaginalis from the female genital tract

Question 24

What are the incubation conditions and duration for Gardnerella?

Answer 24

Detectable growth occurs when incubated at 35°C in 5-10% carbon dioxide within 48 hours of inoculation.

Question 25

Describe the colonial appearance of Gardnerella vaginalis.

Answer 25

forms small, gray, opaque colonies surrounded by a diffuse zone of beta-hemolysis.

Question 26

Describe the colonial appearance of Lactobacillus spp.

Answer 26

multiple colonial morphologies, ranging from pinpoint, alpha hemolytic colonies resembling streptococci to rough, gray colonies

Question 27

How is Gardnerella vaginalis typically treated?

Answer 27

It is typically treated with metronidazole. Systemic infections can be treated with ampicillin or amoxicillin.