Bacteria Flashcards
1
Q
Light microscope
A
Can be used for fungi and bacteria
2
Q
Electron microscope
A
Used for viruses. Electron beam instead of light; magnets instead of lenses.
3
Q
Symptom
A
Departure from normal function or feeling which is noticed by a patient, reflecting the presence of an unusual state or disease
4
Q
Signs
A
Detected by someone other than the affected individual
5
Q
Disease
A
Pathological condition of body parts/tissues characterised by an identifiable group of signs and symptoms
6
Q
Infection
A
When an infectious agent enters the body and begins to reproduce
7
Q
Infectious disease
A
A transmissible disease caused by an infectious agent
8
Q
Pathogen
A
Infectious agent that causes disease
9
Q
Host
A
Organism infected by another organism
10
Q
Virulence
A
Relative ability of an agent to cause rapid and severe disease in a host
11
Q
Eukaryote
A
Distinct membrane bound nucleus
Membrane bound organelles
Large, mostly multi-cellular organisms
12
Q
Prokaryote
A
Free floating DNA strand
Flagellum
No membrane bound organelles
Small, mostly single-celled organisms
13
Q
Bacteria
A
No nucleus
Cell walls
14
Q
Viruses
A
Nucleic acids surrounded by protective coats.
Replicate within cells
15
Q
Fungi
A
Are eukaryotes
16
Q
Prions
A
Infectious unusual proteins
17
Q
Koch’s criteria
A
- Specific agent must be associated with every case of the disease.
- Agent must be isolated from a diseased host and grown in culture.
- When the culture-grown agent is introduced into a healthy susceptible host, the agent must cause the same disease.
- The same agent must again be isolated from the infected experimental host
18
Q
Incubation period
A
Time between infection and the appearance of signs and symptoms
19
Q
Prodromal phase
A
Mild, nonspecific symptoms that signal onset of some diseases
20
Q
Clinical phase
A
Typical signs and symptoms of disease are experienced
21
Q
Decline phase
A
Symptoms subside
22
Q
Recovery phase
A
Symptoms disappeared, tissues heal, body regains strength
23
Q
Acute infectious disease
A
Develops and runs its course quickly
24
Q
Chronic infectious disease
A
Develops slowly and usually less severe. May persist for a long/indefinite period of time
25
Latent infectious disease
Symptomless periods between outbreaks of illness
26
Local infectious disease
Confined to a specific area of the body
27
Systemic infectious disease
Generalised illness spread throughout the body tissues
28
Primary infectious disease
Initial infection in a previously healthy indiv.
29
Secondary infectious disease
Occurs in an indiv. weakened by a primary infection
30
3 ways infectious agents cause disease
- Production of poisons e.g bacteria endotoxins & exotoxins
- Direct invasion and destruction of host cells e.g viruses
- Triggering responses from host's immune system leading to disease signs and symptoms e.g fever, sneeze, cough
31
Endotoxins
Part of cell wall of G-ve bacteria. Released when bacteria divide or die
32
Exotoxins
Secreted by bacteria into the host's cell
33
FIV (feline immunodeficiency virus)
Retrovirus.
Attacks cells of immune system destroying ability to fight infection by other agents.
Spread through bites and scratches.
34
Ways to reduce spread of infectious diseases (5)
```
Vaccines
Antimicrobial drugs
Good hygiene and sanitation
Quarantine
Biosecurity
```
35
Emerging disease
Disease recently appeared within a population
36
Causes of (re)emergence of diseases
Evolution of new infectious agent
Antimicrobial drug resistance
Deliberate introduction
Spread of pathogen to new locations
37
Ways of transmitting infectious diseases
```
Air
Bodily fluids
Contaminated food/water
Direct contact with contaminated objects
Animal vectors
```
38
Cocci
Spherical, bead-like shape
39
Bacilli
rod shape
40
Spirilla
Spiral, corkscrew shape
41
Gram positive
- Stains purple
- Thick layer of peptidoglycan
- No outer membrane – more penetrable and less resistant
- Teichoic acids – negative charge
42
Gram negative
- Stains pink
- Thin layer of peptidoglycan
- Outer membrane – protects again lysozyme and penicillin
- More lipids
- less penetrable and more resistant
43
Glycocalyx:
- Capsule
- Slime layer
Sticky layer secreted onto surface of cell by some bacteria. Species specific (identification)
- Adeherence
- Protection against phagocytosis and dehydration
44
Mesosomes
Inward foldings of the cell membrane.
| Area of cell respiration
45
Cell membrane function
- Selective transport of molecules
- Secretion of extracellular enzymes
- Respiration and photosynthesis
46
Fimbriae
Enable bacteria to attach to surfaces and each other
47
Pili
- G-ve bacteria.
- conjugation (transfer of genetic material)
- attachment (tissues & RBCs)
48
Nucleoid
- Single, large, looped molecule of DNA.
- No membrane
- Self duplicating
49
Plasmids
Small, circular, additional pieces of DNA which can replicate independently.
New genes can be inserted so the bacteria can synthesise new products.
50
Endospores
Produced by G+ve bacteria (bacillus & clostridia). Contains all material necessary to produce a new bacterial cell.
51
3 stages of endospore germination
- activation
- germination
- outgrowth
52
Generation time/doubling time
Time taken for a complete division cycle via binary fission.
| Usually < 30mins
53
4 Stages of growth
- lag phase
- log/exponential phase
- stationary phase
- death phase
54
Lag phase
growth rate = 0 (no increase in cell #)
| cells increase in size
55
Exponential phase
Max growth rate
56
Stationary phase
cell deaths = cell births (no pop. growth)
| Growth limitation due to exhaustion of essential nutrients and build-up of toxins
57
Death phase
decline in population due to lack of space and nutrients and toxic waste build-up
58
Psychophiles
Cold-loving bacteria (0-15C)
59
Mesophiles
Grow best at body temp. (15-40C)
60
Thermophiles
Heat-loving bacteria (40-68C)
61
Obligate aerobes
Require O2 for biosynthesis
62
Facultative aerobes
Do not require O2 for biosynthesis
63
Microaerophiles
Require O2 at pressures < 2atm
64
Anaerobes
Unable to use O2 as a terminal e- acceptor for energy generation
65
Aerotolerant
Anaerobes not harmed by O2
66
Aerophobic (obligate anaerobes)
Anaerobes harmed by O2
67
Symbiosis
close association of two living species
68
Mutualism
Both organisms benefit
69
Commensalism
One benefits, other is neutral
70
Neutralsim
Neither affects the other
71
Parasitism
Microbe benefits at expense of host
72
Conditions for growth
```
moisture
warmth
correct pH
oxygen level
nutrients
```
73
Role of microflora against disease
- Produce inhibitors
- Form aggregates
- Colonise epithelial surfaces
- Compete with pathogens for sites of adhesion
74
Tissue tropism
Normal flora exhibit a tissue preference or predilection for colonisation
75
Skin flora suppresses the growth of potentially pathogenic bacteria and fungi by:
- Competing for essential nutrients
- secreting toxic substances
- Forming bacterial layers over tissue surfaces
76
Significant colonic bacteria
Bifidobacteria
| Lactobacilli
77
Kennel cough
Caused by Bordetella bronchiseptica, G-ve rod
| Vaccine available
78
Skin infections
Staphylococci, G+ve
| cause disease when protective layer of the skin is broken
79
GIT infections
Salmonella, E.Coli, Klebiella. G-ve rods
80
Ear infections
Pseudomonas, G-ve rod
| very resistant bacteria
81
UTI
E.Coli, Pseudomonas, Staphs, Klebsiella. G-ve rod
82
Pasteurella
rabbits: snuffles, pneumonia when stressed. G-ve rod
83
Leptospirosis
Spirochaete, G-ve.
| Zoonosis. Vaccine available
84
Infectious feline anaemia
Mycoplasma haemofelis
85
Clostridial disease
Clostridia, G+ve rods
86
Virulence
Capacity of an organism to cause disease
| Infectivity + Invasiveness + Toxigenicity
87
Adhesins
Substances on the surface of microorganisms that enable attachment to cell surfaces.
Pili, fimbriae, slime layer, capsules
88
Hyaluronidase
Breaks down hyaluronic acid in tissues. 'Spreading factor'
89
Collagenase
breaks down collagen
90
Coagulase
coagulates fibrin; protect against phagocytosis
91
Haemolysins
Destroy RBS's
92
Leukocidins
Destroy neutrophils and macrohages
93
Lecithinase
Breaks down lecithin in cell walls causing cell to lyse
94
Epidemiology
Study of the factors involved in the spread of disease
95
Endemic
Disease always present in a population. Causes localised outbreaks
96
Epidemic
Greater than normal # of cases in a short time period
97
Pandemic
World wide epidemic of a specific disease
98
What is needed to cause an infection?
1. Source of the organism
2. Susceptible host
3. Means of transmission
99
Reservoirs of infection
Any site where a pathogen can multiply or survive until it is transferred to a host.
Living or innate
100
Animals incubating a disease
Appear healthy but may be infectious
101
Animals with overt disease
display clinical symptoms, route of shedding depends on location of disease
102
Convalescent carrier animals
Recovering from disease but organisms still shed
103
Contact carriers/Subclinical infections
carry pathogenic organisms without getting disease themselves
104
Proteus
Cause UTI
105
Klebsiella
Cause severe mastitis in cows
106
Clostridia
Produce endospores which enter body via wounds
107
Susceptible hosts
- older animals
- pregnancy/lactating
- poor nutritional status
- low immunity
108
Nosocomial infections
Hospital acquired infections
