Brainscape's Knowledge GenomeTM

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


See full index

Y3 IWB > MICROBIOLOGY- Antimicrobial agents > Flashcards

MICROBIOLOGY- Antimicrobial agents Flashcards

1
Q

Define antibiotics

A

They are the products f microbes that, in dilute solution, inhibit or kill other organisms

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

Define antimicrobial agents

A

These include antibiotics and synthetic compounds that have the same effect

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

What can we do to naturally occurring antibiotics

A

We can modify them to give semi synthetics derivatives

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

How can modified antibiotics differ from their parent compound

A

In they antimicrobial activity or their pharmacological properties

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

What 2 effects can antimicrobial agents have?

A
  1. They can inhibit microbial growth

2. They can kill microbes

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

Define static

A

Agents that inhibits microbial growth

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

Define cidal

A

Agents that kill microbes

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

How do we carry out susceptibility testing

A

We grow the bacteria in agar
Then we place disks with varying concentrations of antibiotic solution in the agar and see what reaction that causes with the bacterial culture

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

Name an alternative susceptibility test to the disk method

A

Absylum test strip (e test strip)

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

How does the absylum (e ) test strip work

A

It is a plastic strip with a carefully controlled gradient of the drug to be tested
The greater the area of inhibitor the greater the susceptibility the drug is to the bacteria

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

If you are doing a susceptibility test and you see small colonies of bacteria growing in the zones of clearing what does this mean?

A

It means those bacteria are resistant to the drug and require urgent further investigation

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

What does MIC stand for in microbiology

A

Minimum inhibitory concentration

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

What is the Minimum inhibitory concentration (MIC)

A

It is the lower concentration of antibiotic that prevents visible growth of a particular bacterium

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

What does MBC stand for in microbiology

A

Minimum bactericidal concentration

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

What is the minimum bactericidal concentration (MBC)

A

The lowest concentration of antibiotic that kill a particular bacterium

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

How are MIC and MBC values determined?

A

By using dilution methods

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

What do we mean when we describe drugs as being synergistic?

A

Means they work together

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

What do we mean when we describe drugs as being antagonistic?

A

They work against each other

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

Why are bacteria good targets for the activity go antimicrobial substances

A

As apexes of their metabolism are significantly different from that of humans

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

What provides the basis for the selective toxicity of antibiotics?

A

The fact that antibiotics may act up bacterial reaction that are not found in human cells

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

Why is selective toxicity important?

A

Important so that antibiotics target bacteria and not human cells

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

What are the problems with selective toxicity in the case of penicillin

A

Penicillin allergies arise due to the presence of the thiazolidine ring within the penicillin structure

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

Fungi and protist metabolism is closer to bacteria or humans?

A

Humans

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

What do viruses depend on to be able to replicate

A

Viruses are obligate intracellular parasites that depend almost exclusively upon human metabolism for their replication

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

Viruses are O________ I_______ P________

A

Obligate intracellular parasites

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

What is the problem with using drugs that affect viral replication and spread

A

They are too toxic for humans

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

List the key stages in the replication cycle of a virus

A
  1. Entry
  2. Uncoating
  3. Reverse transcription
  4. Integration
  5. Protease inhibition
  6. Virus replication and assembly
  7. Virus release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Name some antiviral agents

A
  1. Amantadine
  2. Rimantadine
  3. Acyclovir
  4. Gancyclovir
  5. Ribvarin
  6. Zidovudine
  7. Lamivudine
  8. Oseltamivir
  9. Zanamivir
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is amantadine used in?

A

Treatment and prevention of influenza A infection

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

What is Rimantadine used in?

A

Treatment and prevention of influenza A infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How do amantadine and rimantadine work

A

By targeting the viral entry and uncoating process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is Acyclovir and what is used to treat

A

It is a nucleoside analogue used to treat infections caused by the herpes virus (especially herpes simplex virus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is gancyclovir and what is used to treat

A

It is a derivative of acyclovir that is more active against CYTOMEGALOVIRUS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is ribavirin and what is used to treat

A

It is a nuceloside analogue that has a broad spectrum of activity
It is used to treat respiratory syncytial virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is zidovudine (AZT) and what is used to treat

A

It is a revere transcriptase inhibitor

It is used to slow the progression of HIV when the patient has developed AIDs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is lamivudine

A

It is an inhibitor for reverse transcriptase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Other than the virus itself what else can antiviral agents target?

A

Viruses may produce polyproteins that are hydrolysed by specific proteases
These proteases can be targeted by antiviral drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What are antiviral drugs that target proteases called?

A

Protease inhibitors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Give an examples of a protease inhibitor

A

Nelfinavir

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is combination therapy

A

When a range of drugs with different modes of action are used to teat a disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What does HAART stand for and what is it used to control

A

Highly Active Antiretroviral Therapy

Used to delay the emergence of a drug resistance of HIV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

How can we defat emergence of resistance?

A

By using drugs with different modes of action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is AZT

A

zidovudine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the trade name for oseltamivir?

A

Tamiflu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the trade name for zanamivir?

A

Relenza

46
Q

What are oseltamivir and zanamivir

A

They are neuraminidase inhibitors that prevent release of influenza virus from infected cells

47
Q

When was oseltamivir used a lot

A

During the H1N1 influenza pandemic

48
Q

What has happened due to the heavy use of oseltamivir during the H1N1 influenza pandemic

A

Has led to the emergence of distant strains of the H1N1 influenza virus

49
Q

What type of organism are fungi?

A

Eukaryotic organism that share similar metabolic processes with humans

50
Q

Why are there only a relatively small number of anti fungal drugs?

A

As we can only use a small number of them safely with out damaging human cells

51
Q

Give examples of classes anti fungal drugs we can use safely

A
  1. Polyenes
  2. The azoles
  3. Miscellaneous
52
Q

How do polyenes work?

A

By binding with sterols in eukaryotic membranes causing their destabilisation

53
Q

Give examples of polyenes

A

1, Nystatin

  1. Amphotericin B
  2. 5 flucytosine
54
Q

What are nystatins used to treat?

A

Oral and genital candida infections

55
Q

What is Amphotericin B used to treat

A

Used for treatment of systemic mycoses

56
Q

What is the problem associated with Amphotericin b and how do we overcome this problem

A

It is potentially toxic to humans and is often given with a second anti fungal or in a lipid preparation

57
Q

What is Amphotericin B often administered with?

A

5 flucytosine

58
Q

Why is Amphotericin B usually given with 5 flucytosine

A

As combining these 2 drugs allows a lower dose of Amphotericin B to be used

59
Q

What is 5 flucytosine (5-FC)

A

It is a synthetic pyrimidine that is metabolised in fungi to 5 flurouracil

60
Q

What is 5 flucytosine used against?

A

Primarily active against pathogenic yeasts

61
Q

How does 5 flucytosine work

A

Works by interfering with the synthesis of nucleic acids

62
Q

What are azoles

A

They are a large group of synthetic compounds that inhibit ergosterol synthesis

63
Q

What happens if ergosterol synthesis is inhibited?

A

Membrane leakage occurs

64
Q

Name the 2 families of azoles

A
  1. Imidazoles

2. Triazoles

65
Q

Give examples of imidazoles

A
  1. Clotrimazole
  2. Miconazole
  3. Exonazole
  4. Ketoconazole
66
Q

Give examples of triazoles

A
  1. Fluconazole
  2. Itraconazole
  3. Voriconazole
  4. Pasoconazole
67
Q

How are imidazoles used?

A

They are used topically to treat fungal infections

68
Q

Why are imidazoles only used topically

A

As they are too toxic to treat systemic infections

69
Q

How are triazoles used?

A

They have a wide variety of applications

70
Q

What is Fluconazole active against?

A

Only active against yeast and dimorphic fungi

71
Q

Name some miscellaneous anti fungal agents

A
  1. Terbinafore

2. Griseofulvin

72
Q

What is Terbinafore

A

A synthetic anti fungal agent

73
Q

What is Terbinafore sued to treat

A

Skin and nail infection

74
Q

How does Terbinafore work

A

By inhibits ergosterol biosynthesis

75
Q

What is Griseofulvin?

A

A naturally occurring compound

76
Q

How does Griseofulvin work

A

It binds to the portion involved in microtubule formation and prevents separation of chromosomes at mitosis

77
Q

What is Griseofulvin used to treat

A

Ring worms and other fungal infections of the skin or nails

78
Q

The fact that Griseofulvin is naturally occurring means it is what?

A

It is a try antibiotic with fungal properties

79
Q

What are protists?

A

They are unicellular eukaryotes

80
Q

What is difficult to achieve when we are making anti protist agents and why?

A

Selective toxicity is more difficult to achieve as protists are unicellular eukaryotes

81
Q

Give examples of antipritist agents

A
  1. Chloroquine
  2. Mefloquine
  3. Pyrimethamine
  4. Metronidazole
82
Q

What does metronidazole induce?

A

It induces strand breaks in the DNA of sensitive organisms and also disrupts membrane integrity

83
Q

What is metronidazole used to treat

A

Used to treat trichomonad vaginalis and entamoeba histolytic

84
Q

What can antibacterial agents target?

A
  1. The cell wall
  2. Membrane integrity
  3. Protein synthesis
  4. DNA metabolism
  5. DNA packaging
  6. RNA polymerase
85
Q

Cell wall inhibitors target what?

A

Peptidoglycan’s

86
Q

what is the benefit of cell wall inhibitors targeting Peptidoglycan

A

It is a unique biopolymer that contains both L and D amino acids
As it is unique to the cell wall it is the ideal target for agents that show selective toxicity

87
Q

Can antibiotics that interfere with the integrity of the cell wall be toxic to humans?

A

Yes some can eg Bacitracin

88
Q

Name some clinically useful cell wall inhibitors

A
  1. Cycloserine
  2. Fosfomycin
  3. Glycopeptides
  4. B-lactams
89
Q

What do all beta lactic antibiotics have in common

A

They have a 4 membered ring structure: the beta lactic ring

90
Q

Name the first rue antibiotic in clinical practice

A

Benzyl penicillin

91
Q

What is the significance of the beta lactic ring found in beta lactic antibiotics

A

The beta lactic ring forms a structural analogue of d alanyl d alanine
This acts by interferring with penicillin binding proteins like enzymes involved in the synthesis and maintained of peptidoglycan

92
Q

Give examples of FAMILIES of beta lactam antibiotics

A
  1. The cephalosporins
  2. Monobactams
  3. Cabepenems
93
Q

What are the cephalosporins

A

A family of broad spectrum antibiotics

94
Q

What are Monobactams active against

A

Gram negatie bacteria

95
Q

What are the Cabepenems

A

A family of broad spectrum agents

96
Q

Give examples of antibacterial antibiotics that affect membrane integrity

A
  1. Polymyxins
  2. Metronidazole
  3. Gramicidins
97
Q

Give examples of antibacterial antibiotics that affect DNA metabolism

A
  1. Para-aminobenzoic acid
  2. Folic acid
  3. Trimethoprim
  4. Sulphamethoxazole (a sulphonamide drug)
98
Q

Give examples of antibacterial antibiotics that affect DNA

A
  1. Nalidixic acid
  2. Metronidazole
  3. Ciprofloxacin
  4. Moxifloxacin
  5. Levoflocacin
99
Q

Give examples of antibacterial antibiotics that affect protein synthesis

A
  1. Aminoglycosides
  2. Tetracycline
  3. Chloramphenicol
  4. Macrolides
  5. Fusidic acid
  6. Linocosamides
  7. Mupirocin
  8. Linezolid
100
Q

What are the side effects of amino-glycosides

A

Damage to the 8th cranial nerve that can lead to deafness and balance problems in some individuals

101
Q

Give examples of amino-glycosides

A
  1. Streptomycin
  2. Gentamycin
  3. Kanamycin
102
Q

Give examples of antibacterial antibiotics that affect RNA synthesis

A
  1. Rifampicin

2. Nirofurantocin

103
Q

What Is Rifampicin used to treat

A

Tuberculosis and prophylaxis

104
Q

Benzyl penicillin was the first ______ _______ used in clinical practice

A

True antibiotic

105
Q

How do Polymyxins, Metronidazole and Gramicidins work?

A

By affecting membrane integrity

106
Q

How do Para-aminobenzoic acid, Folic acid, Trimethoprim and Sulphamethoxazolework

A

By affecting dan metabolism

107
Q

How do Nalidixic acid, Metronidazole, Ciprofloxacin, Moxifloxacin and Levoflocacin work

A

By affecting DNA

108
Q

How do aminoglycosides, Tetracycline, Chloramphenicol, Macrolides, Fusidic acid, Linocosamides, Mupirocin and Linezolid

A

By affecting protein synthesis

109
Q

How do Rifampicin AND Nirofurantocin work?

A

By affecting RNA synthesis

110
Q

Give examples of antimycobacterial antibiotics

A
  1. Streptomycin
  2. Ethambutol
  3. Pyrazinamide
  4. Isonlazid
  5. Rifampicin

Y3 IWB (31 decks)

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