ID 2

Question 1

Why can’t you stain mycobacteria?

Answer 1

cell wall has high lipid content

Question 2

why can’t you stain mycoplasma/ureaplasma?

Answer 2

no cell wall

Question 3

Why can’t you stain chlamydia?

Answer 3

primarily intracellular + lacks classic peptidoglycan because of decreased muramic acid.

Question 4

What other bugs can’t you stain and why?

Answer 4

Intracellular like Legionella, rickettsia, chlamydia, bartonella, ehrlichia, anaplasma

Question 5

Giemsa staining for

Answer 5

Chlamydia
Borrelia
Rickettsia
*Trypanosomes
*Plasmodium

Question 6

What does PAS stain?

Answer 6

Glycogen, mucopolysaccharides

Question 7

other name for Ziehl-Neelsen

Answer 7

carbol fuchsin

Question 8

What else can you use Ziehl-Neelsen for

Answer 8

1) acid-fast bacteria (nocardia)

2) protozoa (cryptosporidum oocysts)

Question 9

Alternative stain for acid-fast bacteria to Ziehl-Neelsen and characteristics of test?

Answer 9

Auramine-rhodamine for screening (cheep, more sensitive but less specific)

Question 10

Mucicarmine affect?

Answer 10

stains thick polysaccharide capsule of cryptococcus red

Question 11

what else do you use silver stain for?

Answer 11

1) coccidoides
2) legionella
3) H pylori

Question 12

What can you stain viruses with?

Answer 12

Fluorescent antibody stain

Question 13

Example of selective media

Answer 13

Thayer-Martin (contains antibiotics)

Question 14

significance of differential/indicator media?

Answer 14

yields a color change in response to metabolism of certain organisms

Question 15

example of indicator differential media?

Answer 15

MacConkey (contains a pH indicator)

Question 16

culture requirements for H influenza?

Answer 16

Factors V (NAD+) and X (hematin)

Question 17

n meningitides media?

Answer 17

Thayer-Martin

Question 18

How does Thayer-Martin agar work?

Answer 18

1) inhibits gram positives with vancomycin
2) inhibits gram negatives (except neisseria obviously) with trimethoprim and colistin
3) inhibits fungi with nystatin

Question 19

what does Regan-Lowe medium contain?

Answer 19

Charcoal, blood, antibiotic

Question 20

tb culture?

Answer 20

Lowenstein-Jensen agar

Question 21

M pneumonia media?

Answer 21

Eaton agar. Requires cholesterol.

Question 22

Effect on MacConkey agar?

Answer 22

Used for lactose-fermenting enterics. Fermentation produces acid, causing colonies to turn pink.

Question 23

e coli medium?

Answer 23

eosin-methylene blue (EMB) agar

Question 24

affect of EMB agar

Answer 24

colonies with green metallic sheen

Question 25

legionella agar

Answer 25

charcoal yeast extract buffered with cysteine and iron

Question 26

What do you stain fungi with?

Answer 26

Sabouraud's agar

Question 27

Aerobes?

Answer 27

Nocardia Pseudomonas Mycobacterium tuberculosis

Question 28

anaerobes?

Answer 28

Clostridium Bacteroides Fusobacterium Actinomyces

Question 29

Anaerobe characteristics

Answer 29

1) susceptible to oxidative-damage (don't have catalase or superoxide dismutase) 2) foul smelling (short-chain fatty acids) 3) hard to culture 4) produce gas in tissue (CO2 and H2) 5) normal flora in GI tract but pathogenic elsewhere

Question 30

Why are ahminoglycosides ineffective against anaerobes?

Answer 30

ahminoglycosides require O2 to enter into bacterial cells.

Question 31

obligate intracellular bugs

Answer 31

Rickettsia Chlamydia Coxiella

Question 32

why are certain bugs obligate intracellular?

Answer 32

rely on host ATP production

Question 33

facultative intracellular bugs?

Answer 33

``` Salmonella Neisseria Brucella Mycobacterium Listeria Francisella Legionella Yersinia ```

Question 34

immunologic response to encapsulated bacteria?

Answer 34

Opsonized, then cleared by spleen.

Question 35

what vaccines do asplenics need?

Answer 35

1) s pneumo 2) h flu 3) n menigitidis

Question 36

why are vaccines conjugated to a carrier protein?

Answer 36

promotes T-cell activation and class switching

Question 37

what is the pneumococcal vaccine?

Answer 37

1) Pneumococcal conjugate vaccine (PCV), ie Prevnar | 2) PPSV, pneumococcal polysaccharide vaccine with no conjugated protein, i.e. Pneumovax

Question 38

Other conjugate vaccines?

Answer 38

- H influenza type B | - meningococcal vaccine

Question 39

Urease action

Answer 39

hydrolyzes urea to release ammonia + CO2, thus increasing pH.

Question 40

Urease-positive organisms

Answer 40

``` Proteus *cryptococcus H pylori Ureaplasma *Nocardia Klebsiella *S epidermidis S saprophyticus ```

Question 41

catalase MOA

Answer 41

Degrades H2O2 into H2O and bubbles of O2. This prevents H2O2 from being converted to microbicidal products by myeloperoxidase.

Question 42

Catalase positive organisms?

Answer 42

``` Nocardia Pseudomonas Listeria Aspergillus Candida E coli Staphylococci Serrate B cepacia H pylori ```

Question 43

s aureus pigment?

Answer 43

yellow (aureus is latin for gold)

Question 44

pseudomonas pigment?

Answer 44

blue-green

Question 45

Other biofilm-producing bug?

Answer 45

*Nontypeable H influenza

Question 46

What does nontypeable mean?

Answer 46

Unencapsulated

Question 47

Contact-lens associated keratitis caused by?

Answer 47

pseudomonas

Question 48

s aureus virulence factor?

Answer 48

protein A; prevents opsonization and phagocytosis

Question 49

bugs that have an IgA protease?

Answer 49

1) S pneumonia 2) H flu type B 3) Neisseria

Question 50

Function of M protein?

Answer 50

prevents phagocytosis.

Question 51

autoimmune response to ARF MOA?

Answer 51

M protein of group A strep shares similar epitopes to human cellular proteins (molecular mimicry).