Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > sterilization and disinfection lecture 5 > Flashcards

sterilization and disinfection lecture 5 Flashcards

1
Q

What are the three possible outcomes for when an antibiotic is added to bacteria?

A
  1. bacteria are resistant and continue to grow. 2. Bacterial growth stops but the bacteria are not killed and growth will resume after removal of the antibiotic. Killing of the bacteria depends on the immune system. 3. bacteria are killed (Bactericidal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the three possible outcomes for when an antibiotic is added to bacteria?

A
  1. bacteria are resistant and continue to grow. 2. Bacterial growth stops but the bacteria are not killed and growth will resume after removal of the antibiotic. Killing of the bacteria depends on the immune system. 3. bacteria are killed (Bactericidal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What acts on cytoplasmic/ cell wall steps?

A

D-cycloserine, phophonomycine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What acts on membrane steps?

A

bacitracin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What acts on wall steps?

A

glycopeptides (vancomycin) B-lactams (penicillin, cephalosporin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What acts on Dna breakage?

A

metronidazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What acts on DNA replication?

A

DNA gyrase- quinolones (nalidixic acid) floroquinolones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What acts on DNA dependent RNA polymerase?

A

rifampicin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What acts on protein synthesis?

A

oxazolidinones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What acts on folic acid biosynthesis?

A

trimethoprim, sulfonamides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What acts on the cell membrane?

A

polymyxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What acts on 50S inhibitors?

A

marcrolides- erythromicin, lincosamides - clindamycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What acts on 30S inhibitors?

A

tetracycline, aminoglycosides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the minimum inhibitory concentration of an antibiotic?

A

the lowest concentration at which bacterial growth is inhibited. Both bacteriostatic and bactericidal antibiotics have MICs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What determines if antibiotic is bactericidal or bacteriostatic?

A

It is dependent on drug dose and bacterial species and needs to be empirically determined.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What acts on membrane steps?

A

bacitracin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Small zone =_______ large zone =__________

A

small zone is resistant, large zone is sensitive. The more sensitive the bacteria, the larger the zone of inhibition.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What acts on Dna breakage?

A

metronidazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What acts on DNA replication?

A

DNA gyrase- quinolones (nalidixic acid) floroquinolones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What acts on DNA dependent RNA polymerase?

A

rifampicin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What acts on protein synthesis?

A

oxazolidinones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What acts on folic acid biosynthesis?

A

trimethoprim, sulfonamides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What acts on the cell membrane?

A

polymyxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What acts on 50S inhibitors?

A

marcrolides- erythromicin, lincosamides - clindamycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What acts on 30S inhibitors?

A

tetracycline, aminoglycosides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the minimum inhibitory concentration of an antibiotic?

A

the lowest concentration at which bacterial growth is inhibited. Both bacteriostatic and bactericidal antibiotics have MICs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the minimal bactericidal concentration MBC ?

A

The lowest concentration at which bacteria are killed. A bactericidal antibiotic is where the MBC and MIC are close.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How does the MIC DIsc diffusion assay work?

A

antibiotic diffuses out of the disk at a set rate forming a gradient of antibiotic concentration. The agar will be CLEAR at concentrations of antibiotic that inhibit bacterial growth( zone of inhibition) The more sensitive the bacteria, the LARGER the zone of inhib.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Small zone =_______ large zone =__________

A

small zone is resistant, large zone is sensitive. The more sensitive the bacteria, the larger the zone of inhibition.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

The size of a zone correlates to what?

A

the antibiotic concentration which differs between antibiotics.

31
Q

What is resistance dependent on?

A

the clinically achievable doses in the patient. Resistance is determined by the achievable clinical dose.

32
Q

Sensitive =

A

inhibited by 1/2 of the acheivable clinical dose or lower

33
Q

intermediate=

A

inhibited by concentrations higher than 1/2 the acheivable dose

34
Q

resistant =

A

cannot be inhibited by an acheivable dose

35
Q

What are natural (intrinsic) resistance mechanisms?

A

Properties that make the bacteria more resistant. Outer membrane gram - bacteria, type 1 pumps (efflux pumps) , proteases that destroy drugs

36
Q

What is mutational resistance?

A

spread by clonal spread of the mutated bacteria. Mutations of the chromosome. Spread is clonal or vertical. Arise from mutation of the chromosome. Spread is clonal or vertical.

37
Q

What is acquired resistance?

A

Resistance determinants on mobile elements (transposons, plasmids) from other bacteria. Spread can be by spread of resistant bacteria AND spread of the resistance gene.

38
Q

When do chromosomal mutations occur?

A

When DNA polymerase makes errors. Under stress the error rate increases.

39
Q

What type of antibiotics are useful for treating infections with bacteria that have high mutation rates?

A

combination antibiotics ie. mycobacterium tuberculosis

40
Q

How are resistant clones spread?

A

resistant clone mutants are spread person to person in vertical or clonal transmission.

41
Q

What do efflux pumps do?

A

Remove the drug from the bacteria

42
Q

What qualities do efflux pumps have?

A

They can be specific or non specific, intrinsic, acquired, or mutational ( freeing of pump expression) They are modified versions of Gram positive bacteria, Type 1 secretion

43
Q

Where is size exclusion important?

A

gram negative bacteria where the antibiotic has to pass through outer membrane porins * misleading due to porin in outer memb. of gram -

44
Q

Where is active transport used?

A

through the cytoplasmic inner membrane of gram negative and gram positive bacteria. Oxidative phosphorylation for aminoglycosides slow growing cells in biofilms or alternate types. Slow growth states (SCVs) or bacteria in biofilms

45
Q

What are B-lactamases?

A

gram - and gram + bacteria produce B-lactamases enzymes that will inactivate penicillin by cleaving the B lactam ring. Cause modifications

46
Q

What are b lactamase inhibitors?

A

Can be co-administered with penicillin. The inhibitors are harder to cleave so the B lactamase remains bound to the inhibitor essentially keeping it from being available to bind to and cleave the b- lactam antibiotic. * clavulanate- amoxicilin /augmentin i.e CAUSES BETA LACTAMASE TO BE LESS EFFECTIVE

47
Q

What is ESBL ?

A

There are b lactamase resistant forms of b-lactam antibiotics . ESBL is a resistant form (extended spectrum beta lactamases) Cleaves beta lactam antibiotics including methicillin.

48
Q

What is fosomycin cleaved by?

A

fosfomycinases

49
Q

What types of modification will inactivate aminoglycosides?

A

N-acetylation, o-phosphorylation, o- adenylation. Chloramphenicol can be inactivated by acetylation (acetyl transferase)

50
Q

What does target site modification do?

A

PBP modification of a site to prevent interaction with the antibiotic. PREVENT ANTIBIOTIC ACTION. These include mutation to specific targets that are either acquired or mutational.

51
Q

What does MRSA mec A gene encode?

A

Methicillin resistant S aureus (MRSA) mec A gene encodes a new beta lactam resistance PBP - PBP2A that does not bind all b- lactam antibiotics. Used to prevent interaction with the antibiotic.

52
Q

B-lactam resistant Strep pneumonia does what?

A

encodes PBP2X- low level resistance to penicillins, and PBP2B0 low and high level resistance to cephalosporins

53
Q

What do MLS strains have?

A

Macrolide-lincosamide-streptogramin strains have a erthromycin methyltransferase gene that methylates 23S rRNA to prevent interaction of macrolides with the 23S rRna and 50S ribosomal subunit. PREVENTS INTERACTION

54
Q

How does Vancomyocin resistance take place?

A

it is acquired by 7 genes. These genes change the D Ala DAla pentapeptide to D Ala D ser or D Ala D Lac . There are THREE types of vancomycin resistance operons: VanA Van B Van C

55
Q

What is metabolic bypass?

A

Modification or complete substitution of Dihydropteroic acid synthetase and Dihydrofolate reductase. Sulfonamides act as competitive inhibitors

56
Q

Fosfomycin what is it’s target, drug inactivators and resistance?

A

target- NAM syn and NAG , fosfomycinases- inactivate drug, resistance reduces transport

57
Q

B-lactams( penicillin, cephalosporin, carbapenems, monobactas) what are there targets, and resistance factors?

A

target- penicillin binding proteins, drug inact- b-lactamases, res- reduced transport, drug efflux, target alteration.

58
Q

Vancomycin- how does it target alteration/resistance?

A

5th D ala to D ser or D-Lac

59
Q

How do sulfonamides act on resistance?

A

bypass target alteration

60
Q

How do aminoglycosides act on resistance?

A

They lead to drug inactivation through acetylation, phosphorylation, and adenylation.

61
Q

Choramphenicol targets a 50S subunit and acts on protein synthesis by using what type of drug inactivation?

A

acetylation

62
Q

What are sources of infectious agents?

A

Person to person including skin contact, fomites (surfaces) including any surface in contact with people or droplets, instruments

63
Q

What is the best form of cleansing the skin

A

handwashing

64
Q

What are some semi-critical instruments ?

A

contact skin and do not penetrate soft tissue. HEAT STERILIZE or high-level disinfect- nail care instruments.

65
Q

disinfection

A

reduction of pathogenic organisms by processes that fail to meet the criteria for sterilization

66
Q

Sterilization-

A

complete killing /removal of all organisms from a location or material

67
Q

what are autoclaves?

A

use steam pressure to sterilize equipment. Inactivates bact, vir, spores, does NOT inactivate PRIONS like those associated with cr-j disease

68
Q

What is dry heat used for?

A

only for solid items.(metal instruments)

69
Q

What are some methods of disinfection?

A

flushing washing, microwaves, sonication. chem- biguanide- damages membranes, alcohol-collapses cell wall, QACS- disrupt cell membrane, phenolics- denatures proteins and damages membranes.

70
Q

What must be used to eliminate spores?

A

hydrogen peroxide- damages essential cell components of DNA and protein and chlorine (bleach)

71
Q

UV light-

A

damages dna of bacteria and viruses, only acts on surfaces.

72
Q

What is the order of resistance from hardest to kill to easiest?

A

bacterial endospores, mycobacterium tuberc TB, non enveloped (hydrophilic viruses), fungi, vegetative cells, lipid viruses, bacteria - easiest* number of organisms - higher numbers, longer time required

73
Q

What are standard precautions for sanitization?

A

handwashing, use of PPE , patient care equipment, environmental surfaces, injury prevention

Microbiology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions