Microbiology Flashcards
(100 cards)
1
Q
Gram positive stains?
A
Purple
2
Q
What stains pink?
A
Gram negative
3
Q
What is a pathogen?
A
Harmful organism
4
Q
Definition of commensal?
A
Organism that is part of normal flora
5
Q
Opportunistic pathogen?
A
Probably only cause infection in immunocompromised individuals
6
Q
What is a contaminant?
A
Organism that has got into culture by accident
7
Q
Definition of pathogenicity?
A
Ability of a microorganism to produce disease
8
Q
Virulence?
A
Degree of pathogenicity of an organism
9
Q
How do bacteria replicate?
A
Binary fission
10
Q
3 types of atmosphere?
A
Anaerobic - no O2
Aerobic- O2
Microaerophillic - Reduced O2, enriched CO2
11
Q
Which type of bacteria produces exotoxin and where?
A
Gram positive
- Produced inside of cell and exported out
12
Q
Which type of bacteria produces endotoxin? Where?
A
Gram negative bacteria
-Part of gram negative bacterial cell wall
13
Q
Example of moulds and how the reproduce?
A
Aspergillus
Produce spores and hyphae
14
Q
Types of fungi?
A
Moulds
Yeasts
15
Q
Example of yeasts and how they reproduce?
A
Candida
Single cells that reproduce by budding
16
Q
What is candida?
A
Yeast
17
Q
What is aspergillus?
A
Mould
18
Q
Fact file on streptococcus?
- Appearance
- Gram
- Atmosphere
- Types in test
A
Aerobic
- Cocci chains
- Gram positive
- Alpha haemolysis = partial = strep pneumoniae, strep viridans
- Beta haemolysis= Complete= Group A Strep, Group B strep
19
Q
What disease are included in strep pneumoniae?
A
Meningitis
Pneumonia
20
Q
What diseases are included in strep viridans?
A
Endocarditis
21
Q
Give the 3 types of gram positive bacteria?
A
Streptococcus
Enterococcus
Staphylococcus
22
Q
Factfile on enterococcus?
- Gram
- Appearance
- Haemolysis?
A
Gram positive
- Aerobic
- Cocci chains
- Non-haemolytic
23
Q
What is the cause of UTIs and normal gut commensal?
A
Enterococcus
24
Q
Factfile on staphylococcus?
-Test
appearance
Gram
A
-Cocci clusters
-Gram positive
-Coagulase positive (golden)= staph aureus
Coagulase negative (white) = Staoh epidermidis
25
Where is staph aureus found, treatment and what it commonly causes?
- Wounds, infection
- Flucloxacillin
- Common cause of bacteraemia (bac in blood)
26
Explain the process of fever?
- Antigen attacks macrophage
- Releases cytokines
- Travel to anterior hypothalamus of brain
- Stimulates production of prostaglandin E
- Resets bodies thermal set point
- Body perceives it is cold, shivers to conserve heat
- FEVER- growth of pathogens slows if temperature increases
27
Physiological use of fever?
If temperature increases the growth of pathogens slows
28
Diplococci fact file?
Atmosphere
Gram
Example
Gram negative
- Aerobic
- Neisseria gonnhoroea/meningitidis
29
Coliforms fact file?
Gram negative bacilli
- Aerobic bit also can be anaerobic
- E coli, klebsiella, proteus
30
Examples of coliforms?
Klebsiella
E coli
Proteus
31
Examples of Diplococci?
Neisseria gonnhoroea
| Neisseria meningitidis
32
Examples of gut pathogens?
Salmonella
Shigella
E colo 0157
33
What is the first line AB for coliforms?
Gentamicin
34
Fact file on strict aerobes?
Gram negative bacilli
Pseudomonas aeruginosa
Legionella pneumophilia
35
What causes food poisoning?
Campylobacter
36
What does helicobacter Pylori cause?
Gastritis
37
Examples of spiral/curved gram negative bacilli?
Campylobacter
| Heliobacter pylori
38
What is haemophillius influenzae?
Small gram negative bacillus
| Common cause of chest infection, especially in COPD exacerbations
39
Example of a gram positive anaerobic bacilli?
Clostridium spp.
40
What is a gram positive anaerobic bacillus?
Part of normal gut flora
| - produces spores and exotoxin that causes severe tissue damage
41
Examples of gram negative anaerobic bacilli?
Bacteroides spp.
42
When are bacteroides spp. pathogenic?
When found in environments that arent the gut
43
First line treatment for anaerobes?
Metrondiazole
44
Examples of anaerobes?
Clostridium spp.
| Bacteroides spp.
45
Examples of gram negative bacteria?
```
Coliforms
Strict aerobes
H. Influenzae
Bacteroides
Diplococci
```
46
Bacteria in TB?
Mycobacteria
- Thick waxy outercoat
- Ziehl neelson stain
47
What DNA do bacteria have?
Chromosomes and plasmid
48
3 methods of gene transfer?
Transformation
Conjugation
Transduction
49
Transformation?
DNA from dead bacteria taken up by living bacteria and incorporated into plasmids or bacterial chromosome
50
Conjugation?
Sex pilus (fimbria) produced by one bacteria through which plasmid DNA can be transferred
51
Transduction?
Viruses infecting bacteria can transfer bits of DNA from one bacterium to another
52
5 I's of infection?
```
Ingestion
Inhalation
Inoculation
Intercourse
(Mother) to Infant
```
53
Standard infection precautions?
All patients all the time
- Wash hands
- Sharps
- Clinical waste
- PPE
54
Transmission based infection precautions?
Added for known suspected infection
| -Eg hasmat suits, facemasks
55
Antibiotics definition?
Drugs that are used to treat or prevent infection caused by micro-organisms (NOT Antibodies)
56
Bactericidal?
Kill bacteria
57
Bacteriostatic?
Inhibit bacterial growth
58
Antibiotics that work on the cell wall?
Penicillin
Cephalosporins - Ceftriaxone
Glycopeptides - vancomycin
59
What class of AB is ceftriaxone?
Cephalosporins
60
How to tell difference between gram negative and positive organisms?
Cell wall has thicker layer of peptidoglycan in gram positive AND a single phospholipid bilayer
61
Mechanism of penicillins?
Inhibit cell wall synthesis by preventing cross-linking of peptidoglycan subunits
62
Penicillin is not a beta-lactam AB? True or False
FALSE
| Beta-lactam AB
63
How is penicillin excreted?
Rapidly through kidneys
64
Examples of penicillin AB's?
Flucloxacillin, Co-amoxiclav, amoxicillin
65
What is flucloxacillin used for?
Skin and soft tissue infection
Wound infection
Cellulitis
66
Mechanisms of cephalosporins?
Inhibit synthesis of cell wall
They are bactericidal
Excreted by kidneys
67
Examples of beta-lactam AB's?
Penicillin
| Cephalosporins
68
Risk of cephalosporins?
May induce clostridium difficile infection so their use is limited in hospitals
69
How are penicillin and cephalosporins the same?
- Bactericidal
- Inhibit cell wall synthesis
- Beta-lactam AB
- Excreted through kidneys (Pen more rapidly)
70
Mechanism of Glycopeptides?
Cell wall active ABs
Binds to end of growing chain, prevents cross-linking and weakens bacterial cell wall
-Bactericidal
-Excreted in urine
71
Example of glycopeptide?
Vancomycin
72
What are glycopeptides only active against?
Organisms with gram positive cell walls
73
ABs that work on the cell wall?
Glycopeptides
Penicllin
Cephalosporins
74
Examples of macrolides?
Erythromycin
Clarithromycin
Aziothromycin
75
Example of a tetracycline?
Doxycycline
76
Example of aminoglycosides?
Gentamicin
77
How do macrolides, aminglycosides and tetracyclines work generally?
The attach to bacterial ribosomes
78
Macrolides and tetracyclines are bacteriocidal/bacteriostatic?
Bacteriostatic
79
Aminoglycosides are bactericidal/bacteriocidal?
Bactericidal
80
Mechanism of macrolides?
They pass through cell membranes very easily (lipophillic)
| -Excreted via biliary tract
81
Risk factors of tetracyclines?
Broad spectrum- can destroy intestinal flora
| -can permenantly stain teeth of children
82
How is doxycycline excreted?
Via biliary tract
83
Mechanism of aminoglycosides?
Inhibit protein synthesis but are bactericidal
Mainly active against gram negative aerobic organisms
eg coliforms, pseudomonas
-Excreted in urine
84
Risk factors of aminoglycosides?
High toxicity
| -Kidney damage and damage of CN VII(deafness and dizziness)
85
AB's that act on bacterial DNA?
Metrondiazole
Trimethoprim
Fluroquinolones
86
Fact file on metrondiazole?
- Mechanism
- Treats
- Interacts with?
- Causes strand breakage of bacterial DNA
- True anaerobic infections
- Interacts with alcohol
87
What does trimethoprim inhibit?
Bacterial folic acid synthesis
88
Examples of fluroquinolones?
Ciprofloxacin
| Levofloxacin
89
What do fluoroquinolones do? Mechanism? Excreted?
Prevent supercoiling of bacterial DNA
- Bactericidal
- Excreted in urine
90
Why are fluorquinolones restricted in their use?
May cause C.difficile
91
Risk factors of fluoroquinolones?
Weakens tendons
| Causes seizures
92
General side effects of ABs?
Nausea
Vomiting
Diarrhoea
Can affect absorption of oral contraceptives
93
Side effects of ciprofloxacin?
Tendonitis
94
Which ABs should be avoided only in the first 3 months of pregnancy?
Metrondiazole
| Trimethoprim
95
Which ABs should be avoided in pregnancy?
Gentamicin
Tetracyclin
Fluoroquinolones
(metrondiazole/trimethoprim first trimester)
96
How AB resistance occurs?
- Changes in bacterial DNA can causes change in gene product which is a target of ABs
- Destruction of AB, bacteria can code for enzymes that chemically degrade or inactivate the AB
- Increased efflux (pump AB out of cell)
97
Stages of viral replication?
-Attachment
-Entry - endocytosis
-Uncoating - viral nucleic acid released from capsid
-Nucleic acid and protein synthesis - host ribosomes used or polymerases
-Assembly = nucleic acid and proteins packed together
-Release =
Budding- Viruses released with envelope
derived from host cell membrane
Lysis- Virus accumulates until cell bursts,
kills cell
98
Virus detection?
PCR
| Antigen detection
99
Examples of neutralising ABs and what they do?
IgG
IgM
Prevent virus binding to cellular receptors
100
What do cytoxic T lymphocytes do in virus immunity?
Recognise proteins on cell surfaces as foreign and signals infected cell to commit suicide in order to prevent formation of new viruses
