Bacteria

Question 1

Gram Negative

Answer 1

Thin layer of peptidoglycans between outer membrane and cytoplasmic membrane.

Question 2

O Antigen

Answer 2

Surface antigen on gram negative bacteria that is species specific

Question 3

Core Polysaccharide

Answer 3

Contributes to membrane integrity, anchors O antigen

Question 4

Lipid A

Answer 4

An Endotoxin anchoring the core polysaccharide

Question 5

Monocyte/Macrophage interaction with LPS

Answer 5

Production of cytokines IL-1, IL-6, IL-8, and TNFα. Activates C3a and C5a complements, causing histamine release. Activates coagulation cascade.

Question 6

Gram Positive cell wall

Answer 6

Thick outer peptidoglycan layer with teichoic and lipoteichoic acids. Lipoteichoic acids share LPS properties.

Question 7

Acid fast cell walls

Answer 7

Peptidoglycan w/ lipid based polymers woven throughout. Mycolic acid is present as a cord factor.

Question 8

Cell-wall less bacteria

Answer 8

No peptidoglycan. Sterols within bilayer maintain fluidity. Has adhesions on “neck.” Cannon be stained using gram stains or treated with wall inhibiting antibiotics.

Question 9

Pilus & Fimbria

Answer 9

External structures composed of fimbrins, adhesins, and pilins. Responsible for adhesion to host cell surface, communication, virulence factor, and recombination

Question 10

Endospore

Answer 10

Dormant survival form, not metabolically active. Formed as a response to adverse conditions. High amount of calcium Blount to dipiclonic acid.

Question 11

Exoenzyme

Answer 11

Bacterial products that can be degradative or hydrolytic

Question 12

Exotoxins

Answer 12

Proteins secreted by many bacteria. Gram negative can transport via type 3 transportation.

Question 13

A-B toxin

Answer 13

Most common type of toxin. Two units. B-unit binds to host cell receptor. A-unit mediates enzymatic activity (is toxic) and translocates after B-unit binds.

Question 14

Membrane disrupting toxins

Answer 14

Hydrolytic. Pore former, destruction of phospholipid bilayer. Kills host cell.

Question 15

Super Antigens.

Answer 15

Form bridges between MHC II of macrophages and T cell receptors. Causes cytokine storm of IFNγ, IL-1, IL-6, and TNFα.

Question 16

Endotoxins

Answer 16

Structural component of bacteria, released when lysed.

Question 17

Blood Agar (BAP)

Answer 17

Differential medium. Does not hydrolyze RBCs = γ, partially hydrolyzes = α and a green coloration, completely hydrolyzes = β and clearing of agar.

Question 18

Chocolate agar (CHOC)

Answer 18

Enriched medium

Question 19

Thayer Martin/New York Agar

Answer 19

Modified chocolate agar containing antibiotics to prevent growth of genital flora, allowing Neisseria species to grow. Enrichment and selective

Question 20

Mannitol Salt Agar (MSA)

Answer 20

Selective and differential. Staphylococcus will grow. S. aureus will change color from red to yellow.

Question 21

MacConkey (MAC)

Answer 21

Selective and differential. Only some gram-negative will grow. Those that ferment lactose will change the color to red/purple.

Question 22

Sorbitol MacConkey (SMAC)

Answer 22

Modified MAC. Selective and differential. Some gram negative can grow. Those that can ferment sorbitol change the color to red/purple.

Question 23

Hektoen agar

Answer 23

Selective and differential. Salmonella will show as green colonies with black centers. Shigella will show yellow-green colonies. Lactose fermenters will turn it salmon colored.

Question 24

Eosin methylene blue

Answer 24

Selective and differential for Coliforms. Gram-positive can not grow.

Question 25

ENT/BEA

Answer 25

Selective and differential. Inhibits staphylococci and all gram-negative bacteria. Colonies that metabolize esculin form a black precipitate.

Question 26

MYC/SAB

Answer 26

Used for fungi

Question 27

Thiosulfate-Citrate-Bile Salts-Sucrose (TCBS)

Answer 27

selective and differential. All enterobacteria and enterococci are inhibited, as well as all gram-positive bacteria. Vibrio cholera turns the media yellow. Other vibrios are blue. Some non cholera vibrios may produce H2S and have black centers in their blue colonies.

Question 28

Buffered Charcoal Yeast Extract (BCYE)

Answer 28

Enrichment. Grows Gram-negative Legionella pneumophila. Colonies will be white-grey/blue-grey

Question 29

Regan-Lowe/Bordet Gengou

Answer 29

Enrichment medium. Cultures Bordetella Pertussis.

Question 30

Lowenstein Jensen

Answer 30

Selective and enrichment medium used to culture mycobacterium. Penicillins are added to kill gram positive and gram negative bacteria.

Question 31

Catalase test.

Answer 31

Determines if catalase is present. Distinguishes staph from strep. Add H2O2, +/- bubbles.

Question 32

Oxidase test

Answer 32

Determine if Oxidase is present. Add chemical, +,- dark purple color.

Question 33

Coagulase test

Answer 33

Important in identification of S. Aureus and Y. Pestis. +/- agglutination results after antibodies against coagulase are added.

Question 34

Lancefield test

Answer 34

Differentiate between groups of streptococcus. +/- agglutination results

Question 35

Nitrite

Answer 35

Determines if organism can reduce nitrate to nitrite. Red is positive. Can use dipstick

Question 36

Urease

Answer 36

Broth contains urea and a pH indicator. If urease is present, solution turns pink

Question 37

Índole test

Answer 37

If Índole is present, bacteria can split tryptophan. This will turn the test bright red

Question 38

Sugar fermentations

Answer 38

Multiple tubes with different sugars have the same organism added to each, allowing us to determine which sugars can be metabolized by said organism.

Question 39

Susceptibility testing

Answer 39

Discs with various chemicals are added to cultured bacteria. Zones of clarity indicate dying bacteria and show sensitivity to that chemical.

Question 40

CAMP Test

Answer 40

Used to identify S. Agalactiae and Listeria. S. Aureus (known positive) is streaked in a line, and your test is streaked perpendicular to S. Aureus streak without touching. Positive shows an “arrowhead” hemolysis between junction of S. Aureus and CAMP producer.

Question 41

Transformation

Answer 41

Naked DNA uptake

Question 42

Transduction

Answer 42

bacterial DNA transfer via viruses

Question 43

Conjugation

Answer 43

DNA transfer via cell/cell contact.