Gram Pos Bacilli Exam 2 Flashcards Preview

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Flashcards in Gram Pos Bacilli Exam 2 Deck (38)
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1

What organisms are of interest in this section?

Bacillus, Corynebacterium, and Listeria

2

Which Bacillus species are not considered normal flora?

B. cereus, B. circulans, B. licheniformis, B. subtilis

3

Bacillus spp. characteristics?

Large, Gram + Rods
Produces spores
Most are motile, ferment glucose, catalase +

4

Bacillus anthracis general characteristics?

Gamma hemolysis
Non-motile
Encapsulated (inhibits phagocytosis)
Produces endospores
Disease of livestock
**Causative agent of anthrax in humans**

5

ID for Bacillus anthracis?

Colonies- large, opaque, green-gray to white, tenacious
**Ground glass appearance MEDUSSA HEAD**

6

What is the BS level done on Bacillus anthracis for preliminary testing?

Level 2
Confirmative ID at reference labs are Level 3

7

What are the 3 human forms of anthrax?

Cutaneous-malignant pustule, typically not fatal.
Pulmonary or Woolsorter's disease- inhale spores (rare-usually fatal).
Gastrointestinal- ingestion of contaminated meat (rarest form, fatal 25-60% of the time).

8

Anthrax is contagious or not contagious?

Not contagious from person to person

9

What is the treatment of anthrax?

Ciprofloxacin, Doxycycline
Resistant to penicillin

10

What is associated with Bacillus cereus? What is the preferred specimen?

Food poisoning
*The food itself*

11

ID for Bacillus cereus?

Lavender colonies with slight green tinge on SBAP
Beta hemolytic, catalase +, motile

12

Bacillus stearothermophilus is used for?

Control organism in autoclave effectiveness

13

List and describe the agents of bioterrorism.

Category A- highest risk to public health (Clostridium botulinum, Bacillus anthracis, Yersinia pestis).
Category B- have moderate to low mortality rates (Brucella spp.).
Category C- emerging pathogens.

14

What is Listeria and Corynebacterium characteristics?

Gram pos rods
Catalase +
Non-acid fast
Non-spore forming
Both are facultative anaerobes

15

What is the transportation of Listeria monocytogenes?

Ingestion of raw vegetables, contaminated dairy and food products.
*Has been documented to cross the placenta from mother to the developing fetus.*

16

What are the virulence factors of Listeria monocytogenes?

Listeriolysin O- pore forming capabilities. Has hemolytic and cytotoxic capabilities.
Internalin- induces phagocytosis (gets in cells).
Act A- induces cellular extensions on phagocytic cells that are infected with microbe. Helps spread microbe.

17

What are Listeria monocytogenes characteristics?

Beta hemolysis. White, smooth translucent. Bile esculin+
Gram pos rods to coccobacilli in pairs or chains. Don't confuse with Group A or B beta-hemolytic Streptococci.

18

What is the incubation of Listeria monocytogenes?

30-35 degrees C

19

What is the treatment for Listeria monocytogenes?

Ampicillin

20

What is the presumptive ID for Listeria monocytogenes?

End over end tumbling motility.
Umbrella shaped motility pattern via stab in semi-solid agar.
*If isolate small gram positive rod, catalase pos, with narrow zone of beta hemolysis, suspect L. monocytogenes.*

21

How can L. monocytogenes can be differentiated from other Listeria spp.?

A positive CAMP test or Hippurate test

22

How to prevent Listeria monocytogenes spread?

Wash raw produce, don't cut raw meats on wood cutting board with veggies, wash your hands, and keep fridge at 40 degrees F or lower.

23

General characteristics of Corynebacterium spp.?

Non-motile, non-acid fast, and pleomorphic
**Resemble Chinese letters**

24

Which Corynebacterium spp. is not considered normal flora?

C. diphtheriae

25

True/false? Diphtheriods are often considered normal flora and include C. diphtheriae.

False. Normal flora, but does NOT include C. diphtheriae

26

What does the "Chinese letters" appearance come from?

Irregular snapping during cell division

27

What is selective media that can be used for Corynebacterium spp.?

Loeffler's Media
Cystine tellurite media- brown halo
Tinsdale agar- gray-brown halo

28

Which biotype is the most severe and virulent in Corynebacterium spp.?

Gravis type

29

Which organism has metachromatic granules?

Corynebacterium spp.
Methylene Blue stain allows for visualization.

30

What is the presumptive ID for C. diphtheriae?

Urease -, halo on Tinsdale agar, and non-motile