Unit 1

Question 1

Gram positive bacteria

Answer 1

Streptococcus, Staphylococcus, Bacillus, Clostridium, Corynebacterium, Listeria

Question 2

Southern vs. Northern vs. Western Blot

Answer 2

DNA, RNA, protein respectively (Protein visualize with antibody or stain)

Question 3

Sterilization

Answer 3

destroys or eliminates all forms of microbial life

Question 4

Disinfetion

Answer 4

eliminates many or all pathogenic microorganisms except spores. INANIMATE OBJECTS.

Question 5

Antiseptic

Answer 5

reduction of microorganisms on LIVING TISSUE. Do NOT kill spores

Question 6

B-Lactam MOA

Answer 6

prevents cross linking of peptidoglycan via binding to PBP or transpeptidase

Question 7

B-Lactam Classes (x4)

Answer 7

Penicillian, Cephalosporin, carbapenems, monbactems

Question 8

Glycopeptides

Answer 8

inhibits cell wall synthesis. – works at step before penicillian
VANCOMYCIN (doesn’t work on gram neg)

Question 9

Inhibitors of protein synthesis (RIBOSOMAL)

Answer 9

Aminoglycosides (-cidal), linezolid, macrolids, clindamycian, tetracyclin (others = -static)

Question 10

Inhibition of nucleic acid synthesis

Answer 10

Quinolones (-floxan) –> inhibts DNA gyrase
Metramidzole
Rifampin - RNA
Acyclovir - Nucleoside analogs

Question 11

Antimetabolite–>usually folate pathway

Answer 11

sulfanomides, trimethoprim (together make bactrim)

no anerobic coverage

Question 12

Intrinsic resistance

–ex of drug

Answer 12

innate ability of a species to resist an antimicrobial agent through its inherent structural or functional characteristics (ex. vancomycin can’t fit through porin of gram negative bacteria)

Question 13

Mutational resistance

Answer 13

occurs due to chromosomal mutation, may be spontaneous or random

Question 14

Acquired resistance

Answer 14

when a microorganism obtains the ability to resist which it was previously susceptible to. Horizontal gene transfer.

Question 15

3 mechanisms of Acquired resistnace

Answer 15

1. transformation - uptake of short DNA fragments
2. transduction - transfer of DNA via bacteriophage
3. conjugation - transfer of DNA via sex pilus (F plasmid present in donating cell)

Question 16

B-lactamase

Answer 16

splits b-lactam ring of antibiotic. classification based on spectrum of activity.
Carbapenemases - carbapenum hydrolyzing b-lactamase
cephlasporinase

Question 17

Overcome B-lactamase (penicillin resistance)

Answer 17

Use b-lactamse inhibitors –> bind to b-lactamse enzyme and act as competitive inhibitor for actual b-lactam ring
ex. zosyn = penicillian + taxobactum

Question 18

MRSA mode of resistance

Answer 18

expression of MECA gene which encodes a PBP that doesn’t bind b-lactam antibiotics with high affinity
i.e. alter structure of transpepetidase (target site of drug)

Question 19

8 types of antibiotic resistance

Answer 19

1. enzymatic inactivation
2. decreased perm of bacterial memebrane (porins change)
3. Antibiotic efflux (tetracyclin)
4. Altered target site
5. Protection of target site (DNA gyrase is protected from quinolones)
6. overproduction of target
7. bypass antibiotic resistance (development of aux trophs which have growth factor requirements different than wild type)
8. binding of antibiotic (excess binding sites so not filled by antibiotics)