Microbiology I Flashcards
1
Q
Name 5 ways to identify the presence of a pathogen.
A
Direct Microbial Analysis Cultivation Antigenic analysis Genetic analysis Detection of Immune response
2
Q
What are the 4 Direct Detection methods of a pathogen?
A
Direct (needle in haystack)
Culture (isolated colonies from streaks)
Antigenic (antibodies exquisitely accurate)
Genetic (highly specific, very expensive)
3
Q
What happens when the highly accurate detection of microbial antigens by antibodies works?
A
Agglutination
4
Q
What is an Indirect Detection method for identifying a pathogen?
A
Measure an immune response
appearance of antibodies against a microbe
5
Q
What are the 3 broad groups of infectious microbial agents?
A
Normal flora
Opportunists
Pathogens
6
Q
What is another term for a pathogen?
A
Overt or Frank
7
Q
What are 2 categories of opportunists?
A
Normal flora
Outsiders
8
Q
T/F
Viruses can be considered part of the normal flora
A
False
9
Q
Diagnostically, pathogens are usually identified through _____ or _____.
A
Tissue direct assay
Isolation and culture
(both followed by identification)
10
Q
What antibody is present in an acute infection?
A
IgM
11
Q
What is diagnostically relevant for pathogens if Convalescent?
A
Antibody types an [conc]
12
Q
Name an acid fast bacteria and two diseases it causes.
A
Mycobacterium
TB and Leprosy
13
Q
What does India Ink tell you about a bacteria?
A
Capsule presence
14
Q
How is KOH useful in pathogenic determination?
A
Can confirm if its a Fungus
15
Q
What type of Direct Visualization involves pre-labeled antibodies that fluoresce?
A
FITC Serology
16
Q
An In Vitro culture of bacteria can be grown on what?
A
Enriched media (augar) Selective media
*Aerobic or Anaerobic
17
Q
How are viruses cultured?
A
Eggs or cell culture
18
Q
What are 2 enzyme tests used in pathogen identification.
A
Catalase
Oxidase
19
Q
What are the 3 major life forms found on earth?
A
Archaea
Bacteria
Eukaryotes
20
Q
What are the 3 Eucarya genera visible to the naked eye?
A
Zea, Homo, Coprinus
21
Q
What are the 5 classes of infectious agents?
A
Archaea Bacteria Eukaryotes Infectious particles (viruses) Infectious proteins (prions)
22
Q
What are 3 main classes of Eukaryotic infectious agents?
A
Helminths (ascaris, enterobius)
Protozoa
Fungi
23
Q
Name 3 protozoan pathogens.
A
Plasmodium (malaria)
Giardia (giardiasis)
Toxoplasma
24
Q
T/F
Archaea are generally not found as human infectious agents.
A
False
25
What are 3 places Archaea are found in humans?
Colon
Pulp Chamber
one more? ask around
26
Name 2 infectious Prions
Mad cow
| Kuru
27
What virus can withstand more environmental stress, enveloped or naked?
Naked
| envelopes dry out
28
T/F
| All bacteria have Fimbrae.
True
29
T/F
| Bacteria divide at the same rate as Eukaryotes
False
bacteria fastest - 15 min.
Eukarytoic - around 12 hrs
30
What bacterial structure makes phagocytosis much more difficult?
Capsules
31
What is the capsule made out of?
CHO
| carbohydrate
32
T/F
| Prokaryotes have no ribosomes
False
but they are much smaller than eukaryotic
33
What type of Fimbrae binds bacteria to host or other bacteria?
Lectins
34
What is an important structural component of ECM?
CHO
35
Describe dsDNA.
Single circular plasmid
36
T/F
| Bacteria can contain several plasmids
True
37
Size bacterial ribosome:
| Size Eukaryotic ribosome:
70S
| 80S
38
What is the complex ecological biosystem of bacteria called?
Biofilm
39
What is a bacterial cell wall made of?
Polysaccharide chains cross-linked by peptides
40
What are the 2 glucose dimers that make up bacterial cell walls?
N-acetylglucosamine (NAG)
| N-acetylmuramic acid (NAM)
41
What fixes the NAG/NAM/peptide complex to a cell wall in synthesis?
Transpeptidase
| these "spot weld"
42
What is constantly synthesizing and degrading peptidoglycan?
Autolysins
43
What additional features does Gram Negative bacteria have?
Periplasmic space
Outer membrane
Endotoxin (LPS)
44
A gram negative can't hold its alcohol.
| explain.
Gram Negative bacteria lose Cresyl Blue when EtOH applied
45
How many Toll-like receptors are there?
| What is the Toll-like receptor that binds LPS?
10
| TLS-4
46
T/F
| Toll like receptors are highly specific
False
| They are "pattern recognition" so are broadly acting
47
What cytokine affects Endothelial cells in the LPS > TLS-4 cascade?
TNF
48
What are the characteristics of systemic LPS pathology?
```
Intravascular coagulation (blockage)
Hypovolemic shock (from decreased BP)
```
Hypovolemic = Septic
49
What do macrophages secrete in response to LPS?
Proteases (breakdown ECM and collagen)
PGE-2
TNF
50
What relaxes pre-capillary sphincters?
| substance/cell/cytokine
NO
by Endothelial Cells
signalled by TNF-alpha
*can be activated by LPS > TLR-4
51
What is PGE-2 effects on bone?
Signals resorption
*Osteoclast activity
52
What is PAMP and DAMP?
| functions?
Pathogen recognition
(aid WBC's)
Damage recognition
(allow for recognition of damaged cells so PMN's can remove)
53
What division of immunity are PAMP and DAMP in?
Native Immunity
54
What is the most important pro-inflammatory mediator stimulated by Toll-like Receptors?
TNF-alpha
55
What type of enzyme breaks linkages in starch/glycogen?
Amylase
56
What type of polysaccharide is structural?
Cellulose
57
What type of enzyme breaks peptidoglycan?
Lysozyme
*at NAM-NAG linkage
58
How is Chitin related to Peptidoglycan?
chitin: Beta 1-4 NAG
peptidoglygan: Beta 1-4 NAG-NAM
59
T/F
| ECM is made up of glucose molecules stuck in polymer.
True
60
Why does penicillin not harm human cells?
It targets peptidoglycan and humans don't have cell walls
61
What are the 3 steps of effective penicillin action?
1. Bacteria must be growing, using autolysin enzymes called hydrolases
2. Blockage of "spot welding" by binding Transpeptidase
3. Lysis by osmotic pressure
62
What would happen if penicillin were added to cells growing in an isotonic solution?
???
| Probably wouldn't burst but would continue to degrade
63
What type of antibiotics kill bacteria?
| What type inhibit their proliferation?
Bacteriocidal
| Bacteriostatic
64
Why does bacteria use right handed D-AA's in their cell walls?
We digest only L-AA's
65
What type of structure is penicilin?
Beta-Lactam Ring
66
What are 4 methods bacteria have developed to resist Penicillin?
Destroy, Divert, Morph, Stop growing
Penicillin-ase
Pump Penicillin out (outer) membrane
Change shape of Transpeptidase
Decrease Hydrolase Activity
67
What is a side effect of Penicillin's unstable Beta-lactam ring?
Can induce immune response by binding self-proteins
(like platelets, RBC's, macrophage)
*a hypersensitivity
68
What is a facultative bacteria?
Can Respire (O2, Heme) or Ferment
69
What is an aerotolerant anaerobe?
| What is a microaerophilic anaerobe?
Can tolerate O2 but only ferments
| Thrives in low level O2
70
What is the function of Super Oxide Dismutase?
| What is the function of Catalase?
O2- > H2O2
| H2O2 > H2O and O2
71
What 2 enzymes do Obligate aerobes and facultative aerobes have in order to deal with the side effects of Oxygen?
Super Oxide Dismutase
| Catalase
72
Why do strict anaerobes die in the presence of Oxygen?
Don't have Super Oxide Dismutase or Catalase `
73
Clinical periodontal practice is often aimed at reducing what pathogen?
Sub-gingival Anaerobes
74
What 3 ways can bacteria exchange genetic material?
Transformation: Free DNA slurped
Transduction: Viral transfer
Conjugation: Direct transfer
75
T/F
| A plasmid is the dsDNA of a bacterial cell.
False
Plasmid is only part/small pieces and optional and are spread intra and inter cellularly by several means
76
What is the most common mutational change in the cell?
Point mutation
77
Name 3 types of Base Replication Errors.
Point mutation
Base Deletion
Base Insertion
(latter two are frameshift and often fatal )
78
What is a rare but extremely important type of mutation?
Gene duplication
79
What are our 2 major (broadly speaking) defense systems?
Innate immunity and Adaptive immunity
80
Where do all the blood cells and platelets arise?
Stem cells in marrow
81
Innate and adaptive's actions in terms of Specificity, Speed, and Memory.
Innate: broad, fast, no
Adaptive: very slow (1st time), yes
82
Inflammation is part of the _____ immune system but stimulates the _____ immune system.
Innate
| adaptive
83
What are 3 Inflammatory response organs?
Brain - fever
Liver - mark cells for death
Marrow - WBC
84
3 signs Acute Inflammation
| 3 signs Chronic Inflammation
Plasma Proteins, Mast cells, neutrophils
Cell proteins, lymphocytes, macrophage
85
What molecule is released from Sentinel (mast) cells?
Histamine
86
What are the "stop signs" in capillary cells in response to inflammation?
(these allow inflammatory response cells to enter tissue)
cell adhesion molecules
| CAMs
87
Why does material travel slowly through the lymph?
increases chance antigen finds specific lymphocyte
88
What are the primary lymph tissues?
Marrow and Thymus
89
Where are B and T cells 'educated?'
B - marrow
| T - Thymus
90
5 Secondary lymph tissues:
```
lymph nodes
spleen
adenoids
tonsils
Peyer's patches
```
91
What type of receptors are on B-cells?
Ag (antigen) - specific
| aka B cell receptor (BCR)
92
What are Antibodies (immunoglobulins)?
released copies of B-cell receptors specific to certain antigens
*this coats and flags antigens
93
Define TCR.
| Function?
T-cell receptor
unlike B-cell, does NOT leave cell surface
only binds to "processed protein" on surface of other cells
94
Once a TCR binds a processed protein, what is the next step?
Releases Cytokines
95
What region of antigen binds to TCR, BCR?
| How big?
Epitope
| 5-10 AA's
96
Define Antigen:
Any molecule "seen" by BCR or TCR.
97
Other than BCR's and TCR's, what can protein antigens bind to?
HLA (Human Leukocyte Antigen) presenter proteins
98
What are some pathologies of Strep pneumoniae?
*remember, this is Gram +
Pneumonia
Ear aches (toddlers)
Meningitis
99
Why are capsules immunogenic (inductive of adaptive response)?
Coated with antibodies and Opsonized for Phagocytosis
100
When capsules are opsonized, what binds to phagocytes?
Fc portion to Fc receptors on phagocyte
101
T/F
| Strep pneumoniae has a capsule
False
can have capsule or not
*most often has a CHO capsule
102
What is the function of the CHO capsule in Strep. pneumoniae?
protects from phagocytosis (major virulence factor)
103
How are bacteria with CHO capsule dealt with?
B cell binds, internalizes, chops up, and presents to HLA (lymphocyte)
T cell recognizes HLA presenter, releases cytokines
T and B cells then divide into CLONES
B cell makes antibodies
104
What type of antibody do we produce the most of?
IgA - more than all others combined
105
T/F
| All gram positive bacteria have endotoxin, some have exotoxin
True
106
T/F
| Gram positive bacteria have no endotoxin
True
107
T/F
| Endotoxin is secreted
False
| in contrast to exotoxin
108
Most of the normal gut flora is made up of what?
| What does this do?
Gram negative rods
low level leakage of LPS develops our immune system
109
What are 3 types of exotoxins?
Cytolytic - punches holes in membranes
A-B toxins - causes cell dysfunction and death
Superantigens - cytokine storm
110
What recognizes LPS?
TLR-4
111
Lipid prostaglandin, leukotriene mediators, and protein enzymes can be produced by what?
Activated macrophage
112
What macrophage receptor can Gram + peptidoglycan affect?
TLR-2
*generally less potent
113
What does LPS activate directly (3 things)?
this is why innate system can take care of low level Gram-
Hageman factor - coagulation
Platelets - also coagulation
Macrophage - O2-, cytokine, etc
114
What does Gram negative cause in large numbers if in the blood?
```
Hypovolemic shock (CV failure)
Intravascular coagulation (organ shutdown, ARDS)
```
*this comprises Sepsis
115
What do monocytes/macrophage "drool"?
Proteases (breakdown ECM/collagen)
PGE-2
TNF-alpha
116
Because it's been in notes multiple times, what is an important function of TNF-alpha?
Signals NO production relaxing pre-capillary sphincters
117
What are the 3 ways of categorizing exotoxins by action?
Cytolytic - hole punching
A-B toxins - binds to specific host cells
Superantigens
118
What are the most toxic substances known?
| How do they work?
A-B toxins
| as enzymes
119
How does the Shigella A-B toxin work?
cleaves ribosomal RNA
120
How does a Superantigen initiate a cytokine storm?
Incorrectly binds antigen to TCR to HLA class II molecule on APC's (antigen presenting cells)
121
How do superantigens affect the sensitivity to LPS?
Increase 100x
122
What are the 2 major pathological Gram + cocci?
Streptococci
| Staphylococci
123
Major strep pathogen?
Strep pyogenes
124
Major staph pathogen?
Staph aureus
125
How does Strp pyogenes avoid detection?
Incorporates host proteins
126
Sterptococcus pyogenes are histological ______ and Staphylococcus aureus are ______
Chains
| Clusters
127
What gram + pyogenic cocci can use oxygen?
Staphylococcus aureus
128
Compare outer layer of Streptococcus pyogenes and Staphylococcus aureus.
Strept - incorporates host protein
| Staph - secreted binds Fc (covers up opsonin)
129
Bad case of Strept p. leads to...
Scarlet/Rheumatic fever
130
T/F
| flesh eating bacteria can be either strept or staph
True
131
Bad case of Staph aureus can lead to...
Toxic shock
132
T/F
Staph are aerotolerant
Strept are facultative
False
Staph are facultative
Strept are aerotolerant
133
T/F
| Streptococcus are small, white, and non-motile
True
134
T/F
| Streptococcus are found in chains or pairs
True
135
What 4 species of Streptococcus cause most diseases?
Pyogens
Agalactiae
Pneumonia
Viridans
136
How does Streptococcus grow in vitro?
Fastidious (kind of picky)
137
Do Strept use catalase?
negative
138
Are strept resistant to antibiotics?
no
139
Strept do well in microaerophilic conditions
true
140
A relationship good for both organisms is...
mutualism
141
What group of Streptococcus are opportunistic oral flora?
Viridans
142
What are the 3 Pyogenic Streptococci?
pyogenes
agalactiae
pneumonia
143
Hemolysis categories:
Beta
Alpha
Gamma
Beta - complete lysis
Alpha - partial lysis
gamma no lysis
144
What is the major bacterial species in the oral cavity?
Alpha hemolytic Streptococcus viridans
145
What are the 2 Pyogenic Strept?
| What are the 2 Viridans Strept?
S. pyogenes
S agalactiae
(Beta hemolytic)
S. pneumoniae
Viridans Strep.
(alpha hemolytic)
146
Describe S. pyogenes?
Beta hemolytic, Group A
| strept throat, rheumatic fever
147
What Strept is the normal flora of the vagina?
| Describe classifications
S. agalactiae
| Beta hymolytic, Group B, Capsule
148
What Strept causes meningitis?
S. pneumoniae
alpha hemolytic, capsule
149
What are the Gamma hemolytic group?
Enterococcus
150
What 2 bacteria cause endocarditis?
S. pyogenes
| Viridans Strep
151
What varies in the 150 strains of Strep pyogenes?
M proteins
152
What does Strep pyogenes produce that kills leukocytes and destroys clots?
Streptolysins
153
How does Strep pyogenes shut down Complement?
C5a
| C3b
154
S. pyogenes can cause what condition in which bacteria moves throughout tissue?
Cellulitis
155
What 2 types of exotoxin does S. pyogenes produce?
Cytolytic
| Superantigen
156
What are 3 forms of disease caused by S. pyogenes?
Local pyogenic - strep throat, impetigo, cellulits
Toxic systemic - scarlet fever (10% untreated), STSS
Immune Sequelae - Rheumatic fever (cross reactive, type II) Glomerulonephritis (type III hypersensitivity)
157
Toxic systemic disease caused by S. pyogenes is caused by?
Superantigen
*note - systemic, so damage occurs away from infection
158
What is the type II hypersensitivity caused by S. pyogenes?
| Type III?
II - Rheumatic fever
| III- Glomerulonephritis
159
Type II hypersensitivity (like Rheumatic fever) result from?
Direct binding of antibody to epitope on host tissue
160
Type III hypersensitivity (like glomerulonephritis) results from?
What interstitial complexes perform the same process?
Innocent bystander damage via Complement
Arthus Rxns
161
What type of damage is Rheumatic fever?
Type II hypersensitivity
162
What causes Glomerulonephritis as a result of S. pyogenes infection?
Ab-Ag complex binds in glomerulus
| Type III damage
163
Explain Viridans Strep cause of sub-acute bacterial endocarditis?
Prior heart damage leaves it "sticky"
164
What two pathogens cause acute infective endocarditis?
S. aureus
| S. pyogenes
165
What 2 opportunists cause sub-acute infective endocarditis?
Dental Viridans
| Gram negative enterics
166
A previously damaged heart is necessary for these 3 things to cause further damage:
Staph from drug abuse
Dental viridans
Surgery/Enterics
167
General characteristics of Staphylococcus:
Gram +
Very Hardy
Catalase +
Facultative
168
What 3 Staphylococcus cause most infections?
S. aureus
S. epidermidis
S. saphrophyticus
169
What Staph is Coagulase+?
S. aureus
170
What Staph has exotoxin?
| Which causes UTI's?
S. aureus
| S. saprophyticus
171
T/F
| Staph has the nasal cavity to itself.
True
172
What are 4 virulence factors of S. aureus?
```
Protein A (blocks opsonization by binding Fc)
Fibrin binding
Enzymes (spreading factors destroy ECM)
Cytolytic toxins
Superantigens
```
173
What causes Scalded Skin Syndrome in children?
A protease (exfoliative toxin) of S. aureus
174
How does Protein A work?
Binds Fc (on IgG) so receptors can't find Staph
175
How does coagulase work to benefit S. aureus?
Causes fibrin to form a wall around infection.
*Abscess diseases
176
T/F
| Stapholococcus aureus is a very strong pathogen
False
| despite all its tricks
177
Why does S. aureus cause a "true" food poisoning?
The toxin, instead of the bacteria, is the culprit
*toxins very heat stable
178
Some tampons can cause...
TSS - toxic shock syndrome
*S. aureus
179
Toxic shock like syndrome is caused by...
Streptococcus pyogenes
180
Nosocomial:
Iatrogenic:
hospital acquired
| doctor acquired
181
How does Staph share resistance factors?
Promiscuous conjugation
