microbiology Flashcards
(69 cards)
1
Q
describe the steps involved in a gram stain reaction
A
- make film
- flood with crystal violet (blue)
- all cells will take up this dye^
- flood with Lugoi’s iodine
- all stains go blue-black
- de-colourise with acetone
- gram +ve retain dye, gram -ve are de-colourised
- counterstain with a red dye
- gram +ve appear blue-black, gram -ve appear red
2
Q
are exotoxins gram positive or negative?
A
Gram positive
3
Q
are endotoxins gram positive or negative?
A
gram-negative bacteria produce endotoxins
4
Q
What is a pathogen?
A
Organism capable of invading the body and causing disease
5
Q
What is a commensalism?
A
An organism which is part of the normal flora
6
Q
What is pathogenicity?
A
The ability to cause disease
7
Q
What is the lifecycle of a parasite?
A
- parasite
- enters/ attaches to host
- multiplication in host
- causes harm
- release from host
- transmission
8
Q
What is colonisation?
A
Microbes find a new host and start to multiply (no harm done)
9
Q
Exogenous vs endogenous infection
A
Endogenous is if the source of the microbe is the patients own flora
10
Q
Parts of a prokaryotic cell
A
11
Q
How do bacteria attach?
A
Pili
12
Q
What’s an example of an encapsulated infection?
A
Meningitis (can be caused by streptococcus)
13
Q
What is the function of the capsule in a bacteria cell?
A
- protection from immune invasion
14
Q
Exotoxin vs endotoxin
A
- exotoxins are produced inside gram POSITIVE bacteria
- endotoxins are produced on the outside of gram NEGATIVE bacteria
15
Q
What is mycology?
A
Study of fungi
16
Q
What organelles do prokaryotes and eukaryotes have in common?
A
- cell membrane
- DNA
- ribosomes
17
Q
What is an example of non-selective agar plate?
A
Blood agar
18
Q
What is an example of a selective agar plate?
A
Mannitol salt agar
19
Q
What does aerobic mean?
A
With oxygen
20
Q
What does capnophilic mean?
A
With carbon dioxide
21
Q
What does facultative mean?
A
With and without oxygen
22
Q
What does microaerophilic mean?
A
Require small amounts of oxygen
23
Q
What does anaerobic mean?
A
Without oxygen
24
Q
Gram stain reaction steps…
A
- make a film
- crystal violet and iodine (all cells dyed)
- acetone (gram positive cells retain dye (blue/black) and gram negative are decolourised)
- red dye (gram positive are blue black and gram negative are red)
25
What type of bacteria is lipopolysaccharide?
Gram negative endotoxin
26
What shape is cocci bacteria?
Round
27
What shape is bacilli bacteria?
Rod (rice)
28
What is an example of a gram positive cocci bacteria?
Streptococcus mutants
Staphylococcus aureus
29
What does streptococcus mutants cause?
Gingivitis
30
What an example of gram negative bacilli?
Prevotella intermedia
31
What can stapholococcus aureus cause?
Angular chellitis
32
What is an example of gram negative cocci bacteria?
Neissera meningitidis
33
What is an example of gram positive bacilli?
Clostridium tetanii
34
What does staphylos mean?
Grapes
35
What causes MRSA?
Stapholococcus aureus
36
What are common healthcare infections?
C. Dificile and MRSA
37
What causes C. difficile?
Antibiotics
38
What is infection ?
Invasion of the body by pathogenic microbes and the reaction of the tissues
39
Chain of infection…
- infectious agent
- reservoir
- portal of exit
- mode of transmission
- portal of entry
- susceptible host
40
What is an infectious agent?
Microorganism which has the ability to cause disease
41
What is the reservoir in the chain of infection?
Where the microorganisms can live and thrive eg a person or object
42
What is the portal of exit in the chain of infection?
The way the microorganism leaves the reservoir eg sneezing
43
What is the mode of transmission in the infection cycle?
How a microorganism is transmitted from one person to another eg via hands
44
What is the portal of entry in the chain of infection?
How the infection enters another individual eg breathed in
45
What is the susceptible host in the chain of infection ?
The person vulnerable to infection
46
What does transient bacteria mean?
Bacteria not normally found in the body
47
What is an example of commensal bacteria?
S epidermidis
48
How would you take a sample of angular cheilitis?
Take a damp swab
49
What does coagulate mean?
Clumping
50
What are koch’s postulates germ theory of disease?
- microbe must be present in every case of the disease
- microbe must be isolated from the diseased host and growth in pure culture
- disease must be reproduced
- microbe must be recovered from an experimentally infected host
51
Describe the structure of a virus…
Lipid membrane (sometimes)
Protein capsule
DNA/RNA
52
What are the stages of viral replication?
- attachment
- penetration
- uncoating
- synthesis
- assembly
- release
53
What type of virus are influenza viruses?
RNA viruses
54
What should be used to treat patients with a transmittable disease?
Treat every patient the same- SICPs, standard infection control procedures
55
What organelles do prions lack?
DNA/RNA
56
When is the transmission of respiratory viruses more common?
- closed setting
- close contact
- crowding
57
What causes candidiasis?
Candida albicans (fungi)
58
What are the ways to control the hazards in the environment?
- elimination
- substitution
- engineering controls
- administrative controls
- PPE
59
What are the stages in biofilm development?
- adhesion
- colonisation
- accumulation
- complex community
- dispersal
60
What are the benefits of bacteria being in a biofilm?
- protective environment
- coordinated cellular events
- labour division
- less energy used
- survival in numbers
61
What is a biofilm?
Matrix enclosed bacterial or fungal populations adherent to each other and/or to surfaces/interfaces
62
Where does stapolococcus commonly live?
Nose
63
What are the three factors involved in biofilm development?
- microorganism
- conditioning film
- surface
64
What is the glycocalyx?
- surrounds the bacteria cell membrane
- extra cellular matrix
- maintains a hydrated environment
- protective barrier
65
What is dental plaque?
A diverse microbial community (mainly bacteria) found on the tooth surface embedded in a matrix of polymers of bacterial/salivary origin
66
What is the main aetiologies agent associated with caries and periodontal diseases?
Dental plaque
67
What is an example of an endodontic infection?
Root canal
68
What is an example of a biofilm in the oral cavity?
Plaque
69
What are the stages in caries progression?
- adhesion
- survival and growth
- biofilm formation
- complex plaque
- acid
- caries
