STEP 1 Gram Positive Bacteria 2

Question 1

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

Answer 1

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

Question 2

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

Answer 2

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

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

Question 3

Features of cutaneous anthrax

Uncommonly progresses to what?

Answer 3

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

Question 4

Pathogenesis of pulmonary anthrax

Answer 4

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

Question 5

Bacillus cereus pathogenesis

Answer 5

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

Question 6

Emetic type of B. cereus

Answer 6

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

Question 7

Diarrheal type of B. cereus

Answer 7

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

Question 8

Listeria monocytogenes algorithm findings

Answer 8

Gram + rod

Facultative intracellular microbe

Question 9

How is listeria acquired?

Answer 9

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

Question 10

How does listeria avoid antibody?

Answer 10

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

Question 11

Listeria and LPS

Answer 11

**ONLY GRAM + ORGANISM TO PRODUCE LPS

Question 12

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

Answer 12

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

Question 13

How to treat listeria..if gastroenteritis? meningitis?

Answer 13

Gastroenteritis is usually self-limited

Ampicillin in infants, immunocompromised, and elderly

Question 14

Actinomyces and Nocardia appearance

Answer 14

Both form long, branching filaments RESEMBLING fungi

Question 15

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

Answer 15

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

Question 16

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

Answer 16

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

Question 17

3 mycobacteria microbes

Stain?

Answer 17

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

Question 18

M. Tb causes what?

Symptoms?

Answer 18

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

Question 19

M. kansasii causes what?

Answer 19

TB-like symptoms

Question 20

MAC is present in which patient population?

Prophylactic treatment?

Answer 20

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

Question 21

TB:

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

Answer 21

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

Question 22

TB:

______ (surface glycoplipids) inhibit _____ fusion

Answer 22

Sulfatides (surface glycoplipids) inhibit phagolysosomal fusion

Question 23

Mycobacterium algorithm:

Answer 23

Acid fast bacilli…does NOT gram stain well

Question 24

Two types of leprosy…which is lethal?

Answer 24

Lepromatous and Tuberculoid forms.

Lepromatous form is lethal

Question 25

TB animal reservoir in US?

Answer 25

Armadillos

Question 26

Lepromatous form presentation:

Answer 26

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

Question 27

Tuberculoid form presentation:

Answer 27

Limited to a few, hypoesthetic hairless skin plaques

High cell-mediated immunity with a largely Th1-type immune response