Microbiology Lab Quiz Study Prep

antigen

Molecule capable of inducing an immune response; stimulates antibody production.

antibody

Protein made by plasma cells that binds/neutralizes pathogens.

agglutination

Clumping of cells when specific antibodies bind particulate antigens.

Agglutination Example

Bacterial cells + antibodies → identification of strain

bacterial antigens

cell wall, flagella, capsules

hemagglutination

Agglutination of RBCs when antibodies bind RBC antigens.

antiserum

Serum containing polyclonal antibodies; used for detection/passive immunity.

RBCs

Carry oxygen

WBCs

Fight infection

platelets

Blood clotting

plasma

Liquid portion of blood; contains fibrinogen

serum

Liquid after blood clots; NO fibrinogen

fibrinogen

Clot-forming precursor protein

What is the universal donor?

O

What is the universal recipient?

AB

Hemagglutination

clumping of red blood cells (RBCs) when antibodies bind to matching antigens

If the antibody matches the antigen what occurs?

clumping

If the antibody doesn't match the antigen or vice versa there is

NO reaction

What is the most important Rh antigen?

D antigen

What RBCs HAVE the D antigen?

Rh+

What RBCs do NOT have the D antigen?

Rh-

How do you detect Rh type?

Mix RBCs with anti-D antiserum

What does it mean when the RBCs and anti-D antiserum clump?

D antigen is present --> Rh+

If there is no clumping when RBCs and anti-D antiserum are mixed then it is

Rh-

If baby's Rh+ blood enters mom's bloodstream it can lead to

birth, trauma, miscarriage

When mom recognizes D antigen as foreign and makes anti-D antibodies this is known as

sensitization

Hemolysis

RBC destruction

What does RBC destruction result in?

high bilirubin, jaundice, hemolytic anemia

RhoGAM

injection of anti-D antibodies; given to Rh- mothers during pregnancy, after birth, miscarriage, trauma

How does RhoGAM work?

destroys Rh+ fetal RBCs before the mom's immune system sees them; prevents mom from developing anti-D antibodies; protects future pregnancies; prevents sensitization

Rh+ can receive

Rh+ or Rh-

Rh- can receive

ONLY Rh-

Skin is inhospitable because

sebum inhibits growth; salt-->hypertonic-->shrivels bacteria; dry keratin layers

What are normal skin microbiota traits?

salt-tolerant, dry-tolerant, more in moist areas (axilla, nose)

Transient microbiota

temporary; from environment, hands

Propionibacterium

use sebum in hair follicles; produce propionic acid-->lowers pH-->microbial antagonism; linked to acne

catalase

breaks toxic oxygen byproducts

coagulase

clots fibrin-->immune evasion-->abscess formation

staphylococcus epidermis

white, tiny colonies; coagulase-; cannot ferment mannitol

staphylococcus aureus

golden colonies; coagulase+; ferments mannitol

MSA result

mannitol ferment --> yellow halo (pH decreases)

How is MRSA detected?

Kirby-Bauer test --> resistant; PCR --> gene mutation

What bacteria is coagulase+?

S. aureus

What bacteria is coagulase-?

S. epidermidis