desinfection

Question 1

what is used during sterilization

Answer 1

physical procedures or chemical agents

Question 2

what is destroyed by sterilization

Answer 2

all microbial forms including bacterial spores

Question 3

physical methods of sterilization include

Answer 3

dry heat, hot steam under pressure, ultraviolet radiation (up to 254nm), ionizing radiation (gamma rays), ultrasonic waves (20kHz), filtration and HEPA filters

Question 4

How high are the temperatures using dry heat and what is used for it?

Answer 4

pasteur oven
160 Degrees for 2h
170 degrees for 1h

Question 5

hot steam uses

Answer 5

autoclave 2atm

121 degrees for 30min and 3 atm 132 degrees for 10min

Question 6

chemical methods of sterilization are

Answer 6

ethylene oxide gas, formaldehyde vapor, hydrogen peroxide vapor, plasma gas (highly ionized hydrogen peroxide gas)

Question 7

How much ethylene oxide gas is used for how long

Answer 7

450-1200mg/L, 29-65 degrees for 2-5h

Question 8

How much and how hot is the formaldehyde vapor?

Answer 8

2-5% and 60-80 Celsius

Question 9

How much and how hot is the hydrogen peroxide vapor?

Answer 9

30%, 55-60 C

Question 10

Desinfektion is used for what

Answer 10

chemical agent to destroy most microbial forms but spores or other relatively resistant m.o.s may remain viable

Question 11

Name the groups of desinfection

Answer 11

high level, intermediate and low level

Question 12

what are high level disinfectants used for?

Answer 12

items involved with invasive procedures that cannot withstand sterilization procedures (e.g., certain types of endoscopes and surgical instruments with plastic or other components that cannot be autoclaved)

Question 13

examples of high level desinfectants are

Answer 13

e.g., glutaraldehyde, hydrogen peroxide, peracetic acid, and chlorine compounds

Question 14

intermediate level desinfectants

Answer 14

used to clean surfaces or instruments where contamination with bacterial spores and other highly resistant microorganisms is unlikely

Question 15

examples of intermediate level desinfectants

Answer 15

(i.e., alcohols, iodophor compounds, phenolic compounds)

Question 16

low level desinfectants are used for

Answer 16

to treat noncritical instruments and devices such as blood pressure cuffs electrocardiogram electrodes and stethoscopes

Question 17

antiseptics are for

Answer 17

skin or other living tissues and inhibit/ eliminate m.o.s

Question 18

Antiseptics are used to

Answer 18

reduce temporarily the number of m.o.s and or eliminate them on skin and mucous membrane surfaces
- no sporicidal action is implied

Question 19

asepsis are

Answer 19

various measures (sterilants, disinfectants and antiseptics)

Question 20

asepsis prevent from

Answer 20

human body from contamination with pathogenic m.o.s

Question 21

what inhibit antibiotics of cell wall synthesis?

Answer 21

1) inhibit bacterial transpeptidases involved in
synthesis of peptidoglycan (β-lactam antibiotics [penicillins, cephalosporins])

2) inhibit cross-linkage (D-Ala-D-Ala) of peptidoglycan layers (glycopeptides [vancomycin, teicoplanin]);

3) inhibit synthesis of mycolic acids (anti-
tuberculosis medicines [isoniazid])

Question 22

what inhibit antibiotics of protein synthesis

Answer 22

1) inhibit functions of bacterial 30S ribosomal
subunit (aminoglycosides, tetracyclines)

2) inhibit functions of bacterial 50S ribosomal
subunit (chloramphenicol, macrolides)

3) inhibit function of tRNAIle (mupirocin)
4) inhibit elongation factor G (fusidic acid)

Question 23

what inhibit antibiotics of nucleic acid synthesis

Answer 23

1) inhibit bacterial DNA gyrase (nalidixic
acid, fluoroquinolones)

2) inhibit bacterial topoisomerase IV (novobiocin);
3) inhibit RNA polymerase β subunit (rifamycins)

4) disrupt bacterial DNA (nitroimidazoles
[metronidazole]

Question 24

what inhibit antimetabolites?

Answer 24

1) dihydropteroate synthetase involved in synthesis of tetrahydrofolic acid (sulfonamides)
2) dihydrofolate reductase involved in synthesis of tetrahydrofolic acid (trimethoprim)

Question 25

disruptor of cell membrane bind to`

Answer 25

• bind to phospholipids in bacterial cell membrane

causing the disruption of membrane and lysis** (polypeptide antibiotics [polymyxins])

Question 26

what causes the binding of phospholipids in the cell membrane?

Answer 26

causing the disruption of membrane and lysis (polypeptide antibiotics [polymyxins])

Question 27

what is the mechanism behind inactivating enzymes which causes bacterial resistance to antimicrobial agents?

Answer 27

→ hydrolysis or modification of antimicrobial agents

Question 28

name examples of inactivating enzymes

Answer 28

betalactamases
aminoglycosidases
chloramphenical-acetyltransferases

Question 29

what is the function of betalactamase?

Answer 29

hydrolyze the betalactam ring of betalactam antibiotics

Question 30

name the function of aminoglycosidases

Answer 30

modify aminoglycosides by means of phosphorylation and nucleotidylation of free hydroxyl groups (phosphotransferases and nucleotidyl transferases) or acetylation of free amino groups (acetyltrans-ferases)

Question 31

explain the function of chloramphenicol acetyltransferase

Answer 31

chloramphenicol acetyltransferases – modification, by acetylation, of chloramphenicol

Question 32

What can be produced based on mutations in natural genes?

Answer 32

gene products with low affinity to antimicrobial agents are produced based on mutations in natural genes

Question 33

how is the target structure altered?

Answer 33

acquisition of the gene for an enzyme that alters the target structure of an antimicrobial agent to render it resistant

Question 34

explain reduced influx

Answer 34

reduction of transport of antimicrobial agents from outside to inside through membranes

Question 35

explain increased efflux

Answer 35

active transport of antimicrobial agents from inside to outside by means of efflux pumps in the cytoplasmic membrane, making efflux greater than influx