STEP 1 Gram Positive Bacteria 2 Flashcards Preview

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Flashcards in STEP 1 Gram Positive Bacteria 2 Deck (27):
1

Causative agent of anthrax?
Algorithm findings?
Which toxin is produced?
**Only bacterium with a ____ capsule...contains ____?

Bacillus anthracis
Gram + aerboic, spore-forming rod
Produces the anthrax toxin
only bacterium with a POLYPEPTIDE CAPSULE (contains D-glutamate)

2

What are the two types of anthrax? Which is deadlier? Which one is commonly called Woolsorter's disease?

Cutaneous (less deadly) and pulmonary anthrax (definitely deadly).

Woolsorter's disease is caused by inhalation of spores from contaminated wool

3

Features of cutaneous anthrax
Uncommonly progresses to what?

Ulcers with BLACK ESCHAR which is painless and necrotic. Uncommonly progresses to bacteremia and death

4

Pathogenesis of pulmonary anthrax

INHALATION of spores --> ILI that rapidly progresses to fever, pulmonary hemorrhage, mediastinitis, and shock

5

Bacillus cereus pathogenesis

Causes FOOD POISONING. Spores survive cooking rice or pasta. Keeping the food warm results in SPORE GERMINATION and ENTEROTOXIN FORMATION

6

Emetic type of B. cereus

N/V causes by preformed toxin. Commonly associated with "reheated rice"
N/V within 1-5 hours

7

Diarrheal type of B. cereus

Causes watery, NON-BLOODY diarrhea and GI pain within 8-18hrs

8

Listeria monocytogenes algorithm findings

Gram + rod
Facultative intracellular microbe

9

How is listeria acquired?

1. Ingestion of UNPASTEURIZED DAIRY PRODUCTS and DELI MEATS
2. Transplancental transmission
3. Vaginal transmission during birth

10

How does listeria avoid antibody?

Moves through cell cytoplasm via actin polymerization and imbeds in cell membrane
**Characteristic TUMBLING MOTILITY

11

Listeria and LPS

**ONLY GRAM + ORGANISM TO PRODUCE LPS

12

Listeria causes what in pregnant women (3), infants and neonates, immunocompromised patients, and healthy individuals

Preggers: amnionitis, septicemia, spontaneous abortion
Infants and neonates: granulomatosis infantiseptica and neonatal meningitis
Immunocompromised: meningitis
Healthy: mild gastroenteritis

13

How to treat listeria..if gastroenteritis? meningitis?

Gastroenteritis is usually self-limited
Ampicillin in infants, immunocompromised, and elderly

14

Actinomyces and Nocardia appearance

Both form long, branching filaments RESEMBLING fungi

15

Actinomyces algorithm:
gram stain
aerobic or not
acid fast stain
flora location
pathogenesis
treatment

Gram + anaerobe
NOT acid fast
Normal oral flora
Causes oral/facial abscesses that drain through the sinus tracts. Forms YELLOW "SULFUR GRANULES"
Treat the sombitch with PCN

16

Nocardia algorithm:
gram stain
aerobic or not
acid fast stain
flora location
pathogenesis
treatment

Gram + AEROBE
WEAK acid fast
Found in SOIL
Causes PULMONARY infections in IMMUNOCOMPROMISED and CUTANEOUS infections after TRAUMA in IMMUNOCOMPETENT
Treat that sombitch with SULFONAMIDES

17

3 mycobacteria microbes
Stain?

Mycobacterium tuberculosis
M. kansasii
M. avium-intracellulare
*All mnycobacteria are acid-fast organisms

18

M. Tb causes what?
Symptoms?

Causes TB...often resistant to multiple drugs...hence the multi-drug regimen
Symptoms: fever, night sweats, weight loss, and hemoptysis

19

M. kansasii causes what?

TB-like symptoms

20

MAC is present in which patient population?
Prophylactic treatment?

MAC typically present in AIDS patients once T-cell count drops below 50.
Treat prophylactically with azithromycin

21

TB:
_____ factor in virulent strains inhibits _____ maturation and induces release of ____

Cord factor in virulent strains inhibits macrophage maturation and induces release of TNF-alpha

22

TB:
______ (surface glycoplipids) inhibit _____ fusion

Sulfatides (surface glycoplipids) inhibit phagolysosomal fusion

23

Mycobacterium algorithm:

Acid fast bacilli...does NOT gram stain well

24

Two types of leprosy...which is lethal?

Lepromatous and Tuberculoid forms.
Lepromatous form is lethal

25

TB animal reservoir in US?

Armadillos

26

Lepromatous form presentation:

Diffusely over skin
Leonine facies
Communicable
Low cell-mediated immunity with a humoral Th2 response

27

Tuberculoid form presentation:

Limited to a few, hypoesthetic hairless skin plaques
High cell-mediated immunity with a largely Th1-type immune response