CA2Prac1

Question 1

List the various colony sizes

Answer 1

pinpoint (<0.1mm), small (0.1-0.5mm), medium (0.5-3.0mm), large (>3.0mm)

Question 2

List the various colony forms

Answer 2

circular, swarming, fliamentous, irregular, rhizoid, undulate

Question 3

List the various colony color or pigments (BA)

Answer 3

white, off-white, gray, yellow

Question 4

List the various colony consistency/textures

Answer 4

Flat/dry (waxy), convex/buttery, droplike/mucoid, glassy, smooth, brittle, sticky

Question 5

List the various colony elevations

Answer 5

raised, flat, convex, droplike

Question 6

List the various colony odors

Answer 6

pungent, sweet, ect

Question 7

What are the BA hemolytic property types

Answer 7

Gamma, beta, alpha, delta

Question 8

Gamma hemolysis

Answer 8

no hemolysis, media is unchanged

Question 9

Beta hemolysis

Answer 9

complete hemolysis, transparent/clear zone around colony

Question 10

Alpha hemolysis

Answer 10

incomplete hemolysis, green bruising

Question 11

Delta hemolysis

Answer 11

incomplete hazy diffusing outward + clear zone (like beta)

Question 12

How to distinguish between Lactose fermentors (+/-/Inde)

Answer 12

(on MacConkey Agar)
L+ = pink/magenta
Linde = almost pink/not one or the other
L- = colorless colonies

Question 13

How to distinguish between Bile precipitate and fisheyes

Answer 13

(on MacConkey Agar)
Bile+ = cloudy/hazy pink around colonies
Fisheye+ = dark middle colony + light zone (when held up to the light)

Question 14

What are the selective properties of MAC

Answer 14

Inhibition of G+ growth
Differentiate between G- Lactose +/-

Question 15

What is the difference between a direct and indirect smear?

Answer 15

Direct smears color the cell, indirect colors the background

Question 16

Describe the appearance of GPC, GP rods, GN rods, Yeast, WBCs, Epithelial cells

Answer 16

GPC - purple circles
GPR - purple lengths
GNR - pink lengths,
yeast - pink/purple peanuts,
WBC/Epithelial cells - take up some stain, larger than microbes

Question 17

Why do GP organisms stain differently than GN organisms

Answer 17

GP - thick peptidoglycan layer and no outer lipid membrane
GN - thin peptidoglycan layer + outer lipid membrane

Question 18

Sources of error (+ results) when performing gram stains

Answer 18

overheated (cell walls rupture and changes dye uptake),
over-decolorized (changes dye uptake),
old culture (G+ looks Neg),
too thick (G- looks Pos)

Question 19

Function of oxidase testing

Answer 19

The oxidase test identifies organisms that produce the enzyme cytochrome oxidase. Cytochrome oxidase participates in the electron transport chain by transferring electrons from a donor molecule to oxygen.

The oxidase reagent contains a chromogenic reducing agent, which is a compound that changes color when it becomes oxidized. If the test organism produces cytochrome oxidase, the oxidase reagent will turn blue or purple within 15 seconds.

Question 20

List oxidase positive organisms

Question 21

List oxidase negative organisms

Question 22

What does a positive oxidase test result look like?

Answer 22

The test should react within 60 sec and turn purple

Question 23

List the colony morphology characteristics of REC, MEC, HEC, Kleb, Entero

Answer 23

Regular E Coli - L+, flat/dry, Bile+, gamma

Mucoid E Coli - L+, mucoid, Bile +, gamma

Hemolytic E Coli - L+, Flat/dry, Bile+ Beta

Klebsiella - L+, mucoid, Fisheye, gamma

Enterobacter - L+, buttery/Inde, Bile-, fisheye-

Question 24

What are the major differences of the E.coli colonies

Answer 24

REC - flat/dry+gamma
MEC - mucoid+gamma
HEC - flat/dry+beta

Question 25

List the colony morphology characteristics of Proteus and Pseudomonas

Answer 25

Pro - L-, clear, med/lg (MAC), gamma, swarming (BA)

Pseu - L-, green/filamentous, beta, lg, metalic sheen

Question 26

Steps to ear cytology sample collection and preparation

Answer 26

Obtain 2 swabs from each ear (sample from junction of vertical and horizontal canal), roll out thin layer on glass slide, no need to heat fix, can stain with diff-quik/mod wrights/gram stain, eval each ear independently, eval for parasites with mineral oil and low power

Question 27

What bacteria are commonly seen in ear cytology?

Answer 27

(cocci) Staphylococcus, Streptococcus, Enterococcus (>5/hpf abnormal)

(rods) proteus, Ecoli, pseudomonas (>2/HPF abnormal)

Question 28

Which class of bacteria are more difficult to treat (ear cytology)

Answer 28

** Pseudomonas?

Question 29

What non-bacterial cells could be found in ear cytology

Answer 29

Malassezia pachydermatitis (5-10/hpf normal, fungus), Inflammatory cells (neutrophils)

Question 30

How do species of bacteria correspond to types of infection?

Question 31

What is the most common species of yeast found in a dog or cat ear?

Answer 31

Malassezia pachydermatitis

Question 32

How are the number of cells and bacteria graded (ear cytology)

Answer 32

0 (0/HPF)
1(1-3/HPF)
2(4-10/HPF)
3(11-30/HPF)
4(>30/HPF)

Question 33

What are some of the common staining methods?
How can you identify the staining method when evalutating a prepared smear?

Answer 33

diff-quick (stains everything blue), Modified Wrights, Gram stain

Question 34

What useful information can be gained from a gram stain of an ear cytology?

Answer 34

can determine G+/- organisms (which allows for fast treatment plans)