Infection and Microbiology Flashcards Preview

Z OLD Tissues of the Body > Infection and Microbiology > Flashcards

Flashcards in Infection and Microbiology Deck (80):
1

What is the biggest kind of microbe?

Eukaryotic

2

What are the smallest microbes?

Viruses

3

What microbes are of intermediate size?

Prokaryotic microbes

4

Do prokaryote microbes have membranes

No- no nuclear membrane or membrane-bound organelles

5

Do prokaryotic microbes have DNA or RNA?

Both

6

What are viruses?

Obligate cell parasites

7

What is meant by obligate?

It has to perform a specific function

8

Do viruses have DNA or RNA?

One or the other, but not both

9

Are all agents of infection microbes?

No

10

What are most deep tissues considered to be?

Sterile

11

Where are microbes predominantly found?

Epithelial tissue

12

Why are microbes predominantly found in epithelial tissue?

All epithelial surfaces are constantly in contact with microbes

13

How was the stomach traditionally considered?

As sterile

14

Why was the stomach traditionally considered sterile?

Because the acid

15

What is now known regarding the stomach?

Some microbes are able to withstand acid, and can therefore infect the stoamch

16

Why aren’t bacteria seen on micrographs?

- They stain poorly with H&E
- Tissue preparation deliberately remove many of them 
- Insufficient magnification 
- Routine histology often ignores or deliberately removes the microbes normally present on/in the human body

17

What do normally resident microbes comprise?

Our microbiomes

18

What is the metabolic power and effect of our microbome comparable too?

At least an organ like the lvier

19

What are differences in individuals’ microbes linked to?

Health and disease

20

How is an individuals microbiome linked to health?

Important for tissue differentiation

21

How is an individuals microbiome linked to disease?

Can be significant in obesity, diabetes and psoriasis

22

What do we need to see microbes?

Special stains and microscopy techniques

23

What does the Gram stain allow?

Detection and beginnings of classification of most bacteria

24

What do acid fast stains allow?

Detection of bacterial causes of TB and leprosy

25

What is the clinical importance of bacteria stains?

Help in diagnosis and treatment of infection

26

What happens in the Gram stain?

- +vely charged crystal violet binds to -vely charged cell components, predominantly nucleic acids 
- Iodine forms large molecular complexes with crystal violet
- Acetone and methanol extract the complexes through the Gram -ve, but not through the Gram +ve cell wall
- Red dye is used to stain the now unstained Gram -ve cells

27

What does the Gram stain reveal?

Profound difference in the cell surface of different types of bacteria

28

What colour do Gram+ bacteria stain?

Dark blue

29

What colour do Gram- bacteria stain?

Red

30

Describe the bacterial cell envelope of a Gram+ bacteria

- Single molecule spreading all the way around the cell surface
- Thicker peptidoglycan covering on outside 
- Cytoplasmic membrane on inside

31

How does the Gram- cell envelope differ from that of the Gram+?

#NAME?

32

Describe the bacterial cell envelope of a Gram- bacteria

- Outer membrane 
- Layer of peptidoglycan 
- Cytoplasmic membrane

33

Give 3 shapes of bacteria

- Cocci
- Rods/bacilli 
- Coccibacilli

34

Give 3 variations of bacteria

- Curved
- Spiral 
- Filamentous

35

Give 2 internal structures of bacteria

#NAME?

36

Give 3 external structures of bacteria

- Fimbrae/pili
- Flagallae 
- Capsule

37

What does the Gram- out membrane consist of?

#NAME?

38

What is significant about the LPS layer?

It is highly toxic

39

What are most symptoms of infection caused by?

The immune reaction

40

Give 3 cell envelope types that can’t be visualised by the Gram stain?

- Mycobacterium 
- Mycoplasmas
- Those that are too small

41

What stains can be used to visualise mycobacterium?

- Acid fast stain 
- Fluorescent 
- Z-N brightfield stains

42

Give an example of an acid fast stain

Turamine

43

Why can’t mycoplasmas be visualised by the Gram stain?

No peptidoglycan

44

Give 2 examples of mycobacterial diseases?

#NAME?

45

What does the mycobacterial cell wall consist of?

- Glycolipids on outside
- Mycolic acid 
- Arabinogalactan 
- Peptidoglycan 
- Plasma membrane

46

What is the advantage of smears for acid fast bacilli?

Rapid

47

What is the disadvantage for smears for acid fast bacilli?

Relatively insensitive

48

What is the clinical importance of cell walls?

- Detection and diagnosis via Gram and acid fast stains 
- Endotoxin effects 
- Target for antibiotics

49

What is the advantage of using bacterial cell walls as a target for antibiotics?

Allows for selective toxicity

50

Give 3 examples of antibiotics that use cell walls as their target

- ß-lactams 
- Glycopeptides 
- Isoniazid

51

Where can bacteria be grown?

- In broth 
- Colonies on agar media 
- Biofilms

52

How do bacteria grow in broth?

Replication by binary fission

53

What does growth in broth give rise to?

Lag, exponential (log) and stationary phases of growth

54

What are the stages that happen when bacteria grow on biofilms?

Attachment →  colonisation →  growth on surface

55

What is the clinical importance of broth turbidity?

#NAME?

56

What is the clinical importance of colonies?

Easy identification and counting of bacteria

57

What is the clinical importance of biofilms?

Can model bacterial growth on medical devices

58

Why is bacterial growth on medical devices important?

Because one of the major reasons for needing to remove intravascular diseases is that they get infected

59

What is the clinical importance of the speed to bacterial growth?

- Rate at which disease develops 
- Time available to diagnose

60

What are the requirements for bacterial growth?

- Specific energy source 
- Specific building blocks 
- Specific atmosphere

61

What atmosphere is required by the majority of bacteria in/on the body?

Absence of oxygen

62

What are the 3 types of organisms, classified by their atmospheric requirements?

- Aerobes 
- Anaerobes 
- Facultative

63

Give 2 Gram+ cocci?

- Staphylococcus 
- Streptococcus

64

Give a Gram+ bacilli

Clostridium

65

Give a Gram- cocci

Neisseria

66

Give 7 Gram- bacilli

- Escherinchia 
- Salmonella 
- Helicobacter
- Pseudomonas 
- Legionella 
- Bacteriodes

67

What is the problem with spore forming groups of organisms?

They are difficult to eliminate with disinfection, because can withstand boiling

68

What are the major groups of prokaryotes?

- Bacteria 
- Archaea

69

What are the features of prokaryotes?

- No membrane-bound organelles 
- 1 chromosome 
- No introns 
- Coupled transcription/translation
- Very labile mRNA

70

What ribosomes to prokaryotes have?

70s (30s+50s)

71

What do all bacteria have?

Peptidoglycan cell wall

72

What prokaryotes don’t have peptidoglycan cell walls?

Mycoplasms

73

What are the major groups of eukaryotes?

#NAME?

74

What are the important features of eukaryotes?

- Membrane-bound organelles 
- Many chromosomes 
- Introns 
- Compartmentalised transcription/translation 
- Stabile and labile mRNA

75

What ribosomes do eukaryotes have?

80s (40s+60s)

76

Do eukaryotes have peptidoglycan cell walls?

No

77

What is infection?

The establishment of an organism on/in a hist associated with its multiplication and damage or dysfunction of host, specifically related to that microorganism or its product

78

What causes infection?

Pathogenic microbes;
- Viruses 
- Prions 
- Bacteria 
- Archaea 
- Protozoa 
- Fungi
- Helminths

79

Why do particular individuals get particular infections?

- Encounter
- Virulence vs. host resistance 
- Innate and adaptive immunity

80

What influences the outcome of an infection?

- Encounter dose and route 
- Virulence and host resistance 
- Innate and adaptive immunity 
- Timely diagnosis and treatment