Sterilization

Question 1

What is the purpose of:

• Laminar flow
• HEPA filter
• UV light

Answer 1

Laminar flow: air circulating
HEPA filter: ensures clean air
UV light: kills microbes

Question 2

What are safety measures of BSL-3?

Answer 2

• Unidirectional air flow
• Filter in ceiling
• Negative pressure
• Trained personnel

Question 3

What are the 3 BSL-3 organisms?

Answer 3

1. Mycobacterium tuberculosis
2. Yersinia pestis (plague)
3. Bacillus anthracis

Question 4

Why did bronchoscopes cause infections even when sterilized?

Answer 4

Mucus on broncho protects the microbes underneath and interferes with sterilization process.

Question 5

Define sterilization.

Answer 5

kills everything, spores and vegetative.

Question 6

What’s the difference between disinfect and antiseptics?

Answer 6

Both kill vegetative. But disinfect is not safe for skin.

Question 7

What are the 3 classifications of disinfectants based on their mode of action?

Answer 7

Modification:

1. Lipids.
2. Proteins
3. DNA

Question 8

What are the disinfectants that modify lipid layer? Examples.

Answer 8

1. Alcohol
2. Detergents
   - Benzalkonium chloride
3. Phenolic compounds
   - Hexaclorophene
   - Lysol

Question 9

What are the disinfectants that modify proteins? Examples.

How?

Answer 9

1. Sulfur Linkage
   - Cholorine (Clorox)
   - Iodine (Tincture, Iodophores)
2. Hydroxy methyl alkylates proteins
   - hydrogen peroxide
   - formaldehyde
   - glutaraldehyde
   - ethylene oxide
3. Heavy metals
   - Thiomerosal
   - Merbromine
   - Silver Nitrate
   - Gonococcal ophthalmia neonatorum

Question 10

What types of microbes can evade hydrogen peroxide?

Answer 10

Those that produces catalase, which degrades hydrogen peroxide to water

Question 11

What are the disinfectants that modify proteins? Examples.

Answer 11

1. Gentian violet
2. Malachite green in lowenstein-jensen media

Positive charge will bind to negative charge DNA and deactivate DNA.

Question 12

What are the physical agents?

Answer 12

1. Heat
   - Moist heat
   - Dry heat
2. Filtration
3. Radiation

Question 13

What are the 3 settings of autoclave?

Answer 13

1. 120C
2. 15 pounds pressure
3. 15 minutes

Question 14

What is spore testing?

Answer 14

To ensure autoclaving is effective.

Put a tube of clostridium botulism into the autoclave with the equipment. Then incubate to see if it germinates. If it doesn’t, autoclave was effective.

Question 15

Name an example of dry heat.

Answer 15

Pasteurization.

Question 16

What is pasteurization?

Answer 16

60C for 30 minutes to kill vegetative forms.

• Salmonella
• Mycobacterium bovis

Question 17

What does filtration do?

Answer 17

Removes endotoxin.

Question 18

What is UV radiation? Ionizing radiation?

Answer 18

UV: Thymine dimerization and inactivates DNA.

Ionizing: Generates hydroxyl radicals that breaks covalent bonds in the DNA.

Question 19

Who found Penicillin?

Answer 19

1928 - Alexander Fleming found in bread mold.

1939 - Florey, Chain, and Associates isolated and synthesized.

1940s - available for general use in US.

Question 20

Staphylococcus aureus is what gram bact?

Answer 20

Gram positive.

Question 21

Chlamydia is what gram bact?

Answer 21

Gram negative.

Question 22

Mycobacterium tuberculosis is what?

Answer 22

Non reactive. Acid-fast bacteria. TB.

Question 23

Haemophilus influenzae is what gram bact?

Answer 23

Gram negative. Capsule is virulent. LPS causes sepsis.

Question 24

Mycoplasma pneumonia causes?

Answer 24

Atypical form of pneumonia.

Question 25

A person who has compromised immune system should be given bacteriostatic of bactericidal?

Answer 25

Bactericidal, must kill the microbes since immune isn't strong enough to kill.

Question 26

``` Chloroarmphenicol Erythromycin Clindamycin Sulfonamides Trimethoprin Tetracyclines ``` Examples of bacteriostatic or bactericidal?

Answer 26

Bacteriostatic.

Question 27

``` Aminoglycosides Beta-lactams Vancomycin Quinodones Rifapin Metronidazole ``` Examples of bacteriostatic or bactericidal?

Answer 27

Bactericidal

Question 28

Beta-lactams does what to microbe?

Answer 28

Interferes with cell wall synthesis, causes cell lysis of bacteria.

Question 29

What bacteria are resistent to beta-lactams?

Answer 29

Those producing beta-latanase, which would degrade beta-lactams.

Question 30

What are examples of beta-lactams?

Answer 30

Penicillin Cephalosporin Imipenem Clavulanate

Question 31

Mechanism of glycopeptides?

Answer 31

Vancomycin prevents cell wall cross-linking enzyme to work effectively. Cell wall synthesis is disrupted.

Question 32

How can a cell be vancomycin resistant?

Answer 32

If they have D-lactate, making vancomycin not fit well. Therefore, the cell wall cross-linking enzyme works fine and cell wall is synthesized.

Question 33

Mechanism of aminoglycosides?

Answer 33

Binds to 30s, making wrong amino acid to join translation. This is irrversible.

Question 34

What are examples of aminoglycosides?

Answer 34

Kanamycin A Gentamicin C1a Neomycin B Streptomycin

Question 35

What are the adverse effects of aminoglycoside?

Answer 35

1. Ototoxicity - reversible vestibular - irreversible suditory 2. Nephrotoxicity - reversible 3. NMJ blockade - a high dose 4. Pregnancy Cat C - 8th nerve

Question 36

T/F: Aminoglycoside is almost always used along with a cell-wall synthesis inhibitor.

Answer 36

True.

Question 37

What is the mechanism of Tetracycline?

Answer 37

Blocks mRNA and prevents amino acid from adding to protein peptide. Bacterial static.

Question 38

What is the adverse effect of tetracycline?

Answer 38

Yellow and degrading teeth.

Question 39

What is mechanism of macrolide?

Answer 39

Bind to 50S and blooc translocation step, peptide bond formation. Bacterialstatic.

Question 40

What is the adverse effects of macrolide?

Answer 40

1. Nausea, vomiting, diarrhea 2. Abdominal pain 3. Liver toxicity (estolate related) 4. *Erythromycin inhibits p-450 (drug interactions) and increase QTc

Question 41

What is mechanism of fluoroquinolones?

Answer 41

Inhibits DNA gyrase and topoisomerase IV. | Bactericidal.

Question 42

What are the adverse effects of fluoroquinolone?

Answer 42

1. Tendon rupture 2. Affects cartilage of children under 18 yo. 3. Pregnancy Category C 4. Seizures, prolonged QT. 5. Dizziness, confusion 6. Photosensitivity.

Question 43

What is mechanism of trimethoprim-sulfamethoxazole?

Answer 43

Inhibits folic metabolism, affecting nucleic acid biosynthesis.

Question 44

What microbe increasing resistant to sulfamethoxazole-trimethoprim combo? What is it most effective?

Answer 44

S. pneumoniae is increasing resistent, therefore limited use for respiratory infections. Excellent for UTI and bacterial diarrheas.

Question 45

Surgical instruments that are sensitive to heat sterilization are sterilized by ____ _____?

Answer 45

Ethylene oxide.

Question 46

These antibiotics work against what? - Bacitracin - b-lactams - fosformycin - glycopeptides

Answer 46

Cell wall construction.

Question 47

These antibiotics work against what? - colisin - polymycin B

Answer 47

Structure and function of the cell membrane.

Question 48

These antibiotics work against what? - aminoglycosides - lincosamide - macrolides - tetracyclines

Answer 48

Protein synethsis.

Question 49

These antibiotics work against what? | - Rifampin

Answer 49

RNA

Question 50

These antibiotics work against what? - Quinolones - Nitrofurantoin - Nitrimidazole

Answer 50

Structure and function of DNA.

Question 51

These antibiotics work against what? - Trimethoprim - Sulfonamides

Answer 51

Folic Acid Synthesis.