Lecture 10-19 Flashcards
(382 cards)
1
Q
What is innate immunity?
A
It is present before any exposure to pathogens and is effective from the time of birth.
It involves nonspecific responses to pathogens
Consists of external barriers plus internal cellular and chemical defenses
2
Q
What is acquired immunity?
A
Adaptive immunity, develops after exposure to agents such as microbes, toxins, or other foreign substances.
Specific response to pathogens
3
Q
What are the chemical mediators in innate immunity?
A
Defensins, lysozymes, complement
4
Q
Cells and tissues of the innate immune system are
A
Granulocytes, macrophages, dendritic and NK cells.
5
Q
Acquired or specific immune systems involve what factors?
A
Cells, tissues
Memory
Discrimination, self/no self
6
Q
Where do T cells mature?
A
Thymus
7
Q
Where do B cells mature?
A
Bone marrow
8
Q
What is the ultimate result of antigen presence?
A
B cell activation which leads to production of antibodies
9
Q
What are some physical barriers involved in the innate immune system?
A
Epidermis Mucous membranes Mucous Lacrimal apparatus Saliva Hairs Cilia Epiglottis Urine Vaginal secretions Peristalsis, defecation, and vomiting
10
Q
What are some chemical factors involved in innate immunity defense?
A
Sebum Lysozyme Saliva Gastric juice Urine Vaginal secretions
11
Q
Why is skin an inhospitable environment for microbes?
A
Salty, acidic, and dry
12
Q
Functions of lysozyme as an antimicrobial secretion
A
Hydrolyzes bond connecting sugars in peptidoglycan
13
Q
Function of lactoferrin as an an antimicrobial secretion in mucous membranes
A
Secreted by activated macrophages and PMNs and sequesters iron from plasma
14
Q
Function of lactoperoxidase as an antimicrobial secretion in mucous membranes
A
Produces superoxide radicals
15
Q
What are two areas of the body that should be completely FREE of microbes?
A
The lower respiratory tract and the bladder
16
Q
What are the innate functions of the respiratory immune system?
A
Mucociliary blanket, alveolar macrophages, and ciliary escalator
17
Q
What are the innate functions of the gastrointestinal immune system?
A
Gastric acid in the stomach
Pancreatic enzymes, bile, GALT, normal microbiota, and peristalsis in the intestines
18
Q
What makes the genitourinary tract an unfavorable environment for foreign microbes?
A
Acidity
19
Q
What are some aspects of the innate immune system in the eye?
A
Lysozyme, lactoferrin, and secretory IgA in tears
Lacrimal apparatus for flushing, eyelashes as barrier
20
Q
Bacteriocins
A
Antimicrobial peptides that are produced by normal flora; toxic proteins that are lethal to other strains of the same species in closely related bacteria
21
Q
Three major activities of the complement system
A
Defend against bacterial infections
Bridging innate and adaptive immunity
Disposing of wastes
22
Q
Opsonization
A
Microbes are coated by serum components (opsonins) in preparation for recognition/ingestion by phagocytic cells; binds to microbial cells, coating them for phagocyte recognition
Antibody and complement C3B together enhance phagocytosis
23
Q
As a pathogen, which complement would you inactivate first in order to inactivate the complement system?
A
C3, followed by C5
24
Q
What activates the classical pathway of complement system?
A
Antigen: antibody complexes (pathogen surfaces)
25
What activates the Lectin pathway of complement system?
Mannose-binding lectin binds mannose on pathogen surface
26
What activates the alternative pathway of complement system?
Pathogen surfaces - activation of C3 forms MAC
27
Name the three potential pathways for activation of the host complement system
Classical pathway, MB-Lectin pathway, and alternative pathway
28
How do bacteria evade the host complement system?
Capsules prevent C activation
Surface lipid-carbs prevent MAC formation
Enzymatic digestion of C5a
29
Soluble proteins or glycoproteins that are released by one cell population that act as intercellular mediators or signaling molecules. These must bind to specific receptors on target cells
Cytokines
30
Autocrine function of cytokines
Affect same cell responsible for their production
31
Paracrine function of cytokines
Affect nearby cells
32
Endocrine functions of cytokines
Spread by circulatory system to distant target cells
33
Chemokines
Specialized cytokines that stimulate chemotaxis and chemokinesis, thus directing cell movement
34
Monokines
Cytokines released from mononuclear phagocytes
35
Lymphokines
Cytokines released from T lymphocytes
36
Interleukins
Cytokines released from one leukocyte and act on another leukocyte
37
Colony Stimulating Factors (CSFs)
Type of cytokine that stimulates growth and differentiation of immature leukocytes in bone marrow
38
Which cytokine increases immunity to viral infection and upregulates cytolytic function?
IFN-alpha
| Innate resistance
39
Which type of cytokine enhances differentiation, enhances antibody synthesis, activates phagocytic function, and enhances antigen processing and presentation?
IFN-gamma
| Adaptive immunity
40
Which type of cytokine upregulates coagulation response, stimulates production and release of acute-phase proteins, and activates phagocytic functions?
TNF
41
IFN-alpha and IFN-beta are interferons that do what?
Cause cells to produce antiviral proteins that inhibit VIRAL replication
42
IFN-gamma is an interferon that does what?
Causes neutrophils and macrophages to phagocytize BACTERIA
43
What innate immune defense kills infected target cells by releasing granules that contain perforin and granzymes? In other words, helps protect cells that have not been able to produce "self" tag?
Natural Killer (NK) cells
*Phagocytes then kill the infected microbes*
44
Neutrophils
Stain at neutral pH, lobed nuclei
Highly phagocytic
45
Basophils
Stain bluish-black or purple with basic dyes
Produce histamine
46
Eosinophils
Stain red with acidic dyes, may appear orange
Kills parasites using lytic factors and perforin
47
Monocytes
Phagocytosis
Later mature into dendritic cells or macrophages
48
Natural killer cells
Destroy target cells, large in size
49
T-cell function
Cell-mediated immunity (cell-mediated response)
50
B cell function
Produce antibodies (humoral response)
Have receptors for unique antigens
51
Platelet function
Blood clotting, small in size
52
Contains specialized cells including Langerhans cell and intraepidermal lymphocytes
Skin Associated Lymphoid Tissue (SALT)
53
Specialized immune barrier that have a "training ground" for immunity responses. Includes gut-associated lymphoid tissue, bronchial-associated lymphoid tissue, and urogenital system.
Mucosal-Associated Lymphoid Tissue (MALT)
54
Name the two mechanisms of phagocytosis
Opsonin-independent recognition
Opsonin-dependent recognition
Phagocytosis can be greatly increased by opsonization
55
Which phagocytosis mechanism involves non-specific pathogen component recognition, with a signaling mechanism involved. May recognize peptidoglycan, flagella, and other surface characteristics.
Opsonin independent mechanism
56
What are the four main forms of opsonin-independent mechanisms?
1. Lectin-carbohydrate interactions
2. Hydrophobic interactions
3. Protein-protein interactions
4. Detection of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRR)
57
What are PAMPs?
Pathogen-Associated Molecular Patterns
Unique to microbes, not present in host
Examples: LPS of gram-negative bacteria, peptidoglycan of gram-positive bacteria
Recognized by PRRs in phagocytic cells
58
What are Toll-Like receptors (TLRs)?
class of pattern recognition receptors that function exclusively as signaling receptors; recognize and bind unique PAMPs of viruses, bacteria, or fungi
The binding triggers signal which is then communicated to host cell nucleus, initiating host response
59
Autophagy
Highly conserved process that tags internal microbes for destruction using monoubiquitination
60
What might a PAMP (pathogen-associated molecular pattern) be in a virus?
Capsid proteins, viral RNA, etc.
61
During intracellular digestion, the phagosome fuses with lysosome to form ______ that will expose the bacteria to hydrolytic enzymes
Phagolysosome
62
How do Streptococcus pyogenes and Streptococcus pneumoniae evade phagocytosis?
Inhibition of adherence: M protein, capsules
63
How does Staphylococcus aureus evade phagocytosis?
Killing phagocytes: Leukocidins
64
How does Listeria monocytogenes evade phagocytosis?
Lysis of phagocytes via membrane attack complex (MAC)
65
How do Shigella and Rickettsia evade phagocytosis?
Escaping the phagosome
66
How do HIV and Mycobacterium tuberculosis evade phagocytosis?
Prevention of phagosome-lysosome fusion
67
Define inflammation
Innate, nonspecific response to tissue injury caused by pathogen or physical trauma; it is the immediate response of the body to injury or cell death
68
What are the cardinal signs of inflammation?
```
Redness
Warmth
Pain
Swelling/edema
Altered function
```
69
What chemical mediators are involved with acute inflammatory responses and what are their functions?
Selectins: cell adhesion molecules on activated capillary endothelial cells
Integrins: adhesion receptors on neutrophils
Chemotaxins: chemotactic factors released by injured cells
70
Describe an acute inflammatory response
Damaged tissue releases inflammatory chemicals called chemokines (kalikrein) - recruit macrophages
Dilation and increased permeability of capillaries brings blood to the area, may result in swelling
Various processes occur: margination, diapedesis, and extravasion
71
What are advantages of fever?
T-cell production increases due to increase in IL-1
Increase transferrins (iron scavenging)
Speeds up repair process
72
What are some disadvantages of fever?
Tachycardia
Acidosis due to increased metabolic rate
Dehydration
Death above 44-46 celsius (112-114 F)
73
What is the result of histamine release by damaged cells?
Vasodilation, increased permeability of blood vessels
74
What is the result of kinins release by damaged cells?
Vasodilation, increased permeability of blood vessels
75
What is the result of prostaglandins release by damaged cells?
Intensify histamine and kinin effect (vasodilation and increased permeability of blood vessels)
76
What is the result of leukotrienes release by damaged cells?
Increased permeability of blood vessels, phagocytic attachment
77
What are the two types of adaptive immunity?
Humoral: antibody-mediated
Cell-mediated: based on action of T lymphocytes
78
Naturally acquired active immunity
Type of specific immunity a host develops after exposure to a foreign substance (consequence of prior infection)
79
Naturally acquired passive immunity
Transfer of antibodies, e.g., mother to fetus across placenta, or through breastfeeding
80
Artificially acquired active immunity
Intentional exposure to a foreign material (vaccination)
Goal is to stimulate antibody production
81
Artificially acquired passive immunity
Preformed antibodies or lymphocytes produced by one host are introduced into another host
Goal is to give antibodies directly
For example: immune globulin therapy
82
What is a hapten and when is it used?
Antigen combined with carrier molecules; used when the antigen is too small to illicit an immune response on its own, but when combined with a carrier molecule the body will recognize it
83
Where are MHC-I molecules found and what type of processing do they use?
MHC class I are found on almost all types of nucleated cells (so not RBCs because they don't have nucleus)
Utilize endogenous antigen processing
84
Where are MHC-II molecules found and what type of processing do they use?
MHC class II molecules are found only on Antigen Presenting Cells (APCs) which are macrophages, dendritic cells, and B-cells
Utilize exogenous antigen processing
85
MHC class I molecules utilize endogenous antigen processing, meaning what?
Class I bind to antigen peptides that originate in the cytoplasm. They then present the antigen to CD8+ T cells (cytotoxic T lymphocytes)
86
MHC class II molecules utilize exogenous antigen processing, meaning what?
Class II binds to antigen fragments that come from outside the cell and present them to CD4+ T cells (Helper T cells)
87
Identify the cells that can function as APCs (antigen presenting cells)
Macrophages
Dendritic cells
B cells
88
What type granular leukocytes destroys cells that don't express MHC I?
Natural killer cells
These also kill virus infected and tumor cells, as well as attack parasites
89
In terms of Cluster of Differentiation Molecules (CDs), what is the MHC class II coreceptor on T cells, monocytes, and macrophages?
CD4
90
In terms of Cluster of Differentiation Molecules (CDs), what is the MHC class I coreceptor on cytotoxic T cells?
CD8
91
Describe T cell receptor structure and function
TCRs are found in plasma membrane surface and contain an antigen binding site
They recognize and bind fragments of antigens presented by APCs
92
Describe B cell receptors structure and function
BCRs are immunoglobulin receptors for specific antigen that will activate that particular B cell
Consist of two light chains and two heavy chains connected with disulfide bonds
93
Explain molecular events resulting in Helper T cell activation
1. APC encounters and ingests microorganism. Antigen is enzymatically processed into short peptides, which combine with MHC class II molecules and are displayed on the surface of APC
2. A receptor on helper T cell binds to the MHC-antigen complex. If this includes a Toll-like receptor (TLR), APC releases costimulatory molecules. These two signals activate helper T cell which produces cytokines
3. Cytokines cause helper T cell to proliferate and develop its effector functions
94
Explain molecular events resulting in cytotoxic T cell activation
1. Response is triggered by abnormal cell (cancer, virus infected, etc.)
2. Abnormal antigen is presented on cell surface in association with MHC-I molecules. CD8+ T cells with receptors for the antigen are transformed into cytotoxic T lymphocytes
3. CTL induces destruction of virus infected cell by apoptosis
95
Explain molecular events resulting in B cell activation through the T dependent pathway
T dependent requires 2 signals before B cell differentiates into plasma cell and memory cell:
Antigen-BCR specific interaction
Activated T helper 2 binds B cell presented antigen and secretes B cell growth factors
96
Explain molecular events resulting in B cell activation through T independent pathway
T independent involves polymeric antigens with large number of identical epitopes (i.e., LPS)
Less effective than T dependent pathway
Antibodies produced have low affinity for antigen
No memory cells are formed; overall weaker immune response
97
Antibodies are also known as immunoglobulin, which are made by activated B cells (plasma cells). What are the 5 immunoglobulin classes?
```
IgG
IgM
IgA
IgD
IgE
```
98
Describe IgG in terms of its valence, abundance, where it is found, and function
Monomer - bivalent (2 binding sites)
80% of serum antibodies
Capable of complement fixation and crossing the placenta
Found in blood, lymph, and intestine
Enhances phagocytosis, neutralizes toxins and viruses, and protects fetus and newborn
**second antibody to appear in response to infection (M is first)
99
Describe IgM in terms of its valence, abundance, where it is found, and function
```
Pentamer - (10 binding sites)
5-10% of serum antibodies
Capable of complement fixation
Found in blood, lymph, and on B cells
Agglutinates microbes, first antibody introduced in response to infection
```
100
Describe IgA in terms of its valence, abundance, where it is found, and function
Dimer (4 binding sites)
10-15% of serum antibodies
Found in secretions
Functions in mucosal protection
101
Describe IgD in terms of its valence, abundance, where it is found, and function
Monomer (2 binding sites)
0.2% of serum antibodies
Found in blood, lymph, and B cells
Functions in initiation of immune response on B cells
102
Describe IgE in terms of its abundance, where it is found, and function
0.002% of serum antibodies
Found on mast cells, on basophils (histamine), and in blood
Functions in allergic reactions; lysis of parasitic worms, opsonization
103
What is "class switching" in terms of antibody kinetics?
Change in antibody class secreted by plasma cells under the influence of T helper cells (i.e., may switch from IgM to IgG); event unfolds with time
104
During primary antibody response, there is a lag period of several days to weeks where there is no antibody detectable in blood. After B cell differentiation into plasma cells, the antibody is secreted. How is an antibody titer calculated?
The titer is the measure of serum antibody concentration
It is the reciprocal of highest dilution of antiserum that gives positive reaction
105
What are the characteristics of a secondary antibody response
B cells mount a heightened memory response:
Shorter lag phase
More rapid log phase
Longer persistence
Higher IgG titer and production of antibodies with higher affinity for the antigen
106
What is combinatorial joining?
The segments clustered separately on same chromosomes have exons that code for constant regions and exons that code for variable regions.
Exons for constant region are joined to one segment of the variable region via RAG-1 and RAG-2 recombination enzymes
107
What is the clonal selection theory?
States that each lymphocyte has membrane-bound immunoglobulin receptors specific for particular antigen and after the receptor is engaged, proliferation of the cell occurs such that a clone of antibody producing cells is produced
108
What is the clonal deletion theory?
The elimination of certain T cell populations in the thymus that have specificity for self-antigens (forbidden clones)
109
Name the 5 consequences of antibody binding of an antigen
```
Agglutination
Opsonization
Complement activation
Neutralization
Antibody-dependent cell-mediated cytotoxicity
```
110
Define agglutination, one of the consequences of antibody binding of antigen
Agglutination reduces number of infectious units to be dealt with by sticking together
111
Define opsonization, one of the consequences of antibody binding of antigen
Coating antigen with antibody, enhancing phagocytosis
112
Define complement fixation, one of the consequences of antibody binding of antigen
Addition of complement causes inflammation and cell lysis
113
Define antibody-dependent cell-mediated immunity, one of the consequences of antibody binding of antigen
Antibodies attached to target cell cause destruction by macrophages, eosinophils, and NK cells
114
Define neutralization, one of the consequences of antibody binding of antigen
Blocks adhesion/attachment of bacteria, viruses, or toxins to mucosa
115
Describe the function of cytotoxic T lymphocyte (CTL)
Destroys target cells on contact; generated from T cytotoxic (Tc) cell
116
Describe the function of an activated macrophage
Enhanced phagocytic activity; attacks cancer cells
117
Describe the function of Natural Killer (NK) cell
Attacks and destroys target cells; participates in antibody-dependent cell-mediated cytotoxicity
118
Which of the cytokines promotes inflammation?
TNF-alpha
119
Which of the cytokines inhibits humoral immunity and activates TH1 cellular immunity?
Interleukin-12 (IL-12)
120
Which of the cytokines responds to viral infection and interferes with protein synthesis?
IFN-alpha and IFN-beta
121
Which of the cytokines stimulates macrophage activity?
IFN-gamma
122
How does Coxiella burnetti escape phagocytosis?
By surviving in the phagolysosome
123
What processes occur in the acute inflammatory response?
Margination
Diapedesis
Extravasion
124
What are the chemicals that are released by damaged cells?
Histamine
Kinins
Prostaglandins
Leukotrienes
125
What are the two types of acquired immunity?
Humoral response
| Cell mediated response
126
Define the humoral response
Antibodies defend against infection in body fluids
127
Define cell-mediated response:
Cytotoxic lymphocytes defend against infection in body cells
128
Compare and contrast innate and acquired immunity
Innate: recognition of trait shared by broad ranges of pathogens using a small set of receptors. Rapid response
Acquired: recognition of traits specific to particular pathogens, using a vast array of receptors. Slower response
129
```
All of the following are involved in keeping the lower respiratory tract free of microorganisms except:
A. Ciliary escalator
B. Epiglottis
C. Alveolar macrophages
D. Lacrimal apparatus
```
D. Lacrimal apparatus
130
```
Which of the following pathways for complement activation is generally dependent upon the formation of antigen-antibody complexes?
A. The classical pathway
B. The alternative pathway
C. The lectin pathway
D. All of the above
```
A. The classical pathway
131
```
Which leukocytes function to produce toxins against certain parasites?
A. Lymphocytes
B. Basophils
C. Eosinophils
D. Neutrophils
```
C. Eosinophils
132
```
Which host defense is more effective against gram positive bacteria than gram negative bacteria?
A. Mucus
B. Sebum
C. Gastric juice
D. Lysozyme
```
D. Lysozyme
Because of thicker layer of peptidoglycan, it will have a greater impact -- gram negative are protected by outer membrane
133
Natural killer cells specifically kill which of the following?
A. Gram positive
B. Gram negative
C. Fungi protozoa
D. Tumor cells and cells infected by microorganisms
D. Tumor cells and cells infected by microorganisms
134
```
Each of the following is an effect of complement activation, except:
A. Opsonization
B. Increased phagocytic activity
C. Interference with viral replication
D. Increased blood vessel permeability
```
C. Interference with viral replication
135
```
Eosinophils defend against protist and helminth parasites by:
A. Phagocytosis
B. Complement activation
C. Antibody production
D. Releasing perforin and lytic enzymes
```
D. Releasing perforin and lytic enzymes
136
Which of the following is INCORRECTLY matched?
A. PAMP - peptidoglycan
B. TLR - stimulation of the inflammatory response
C. Histamine - vasodilation
D. None of the above
D. None of the above
137
Class II major histocompatibility complex molecules are found on all of the following except:
A. B cells
B. T cells
C. Dendritic cells
D. None of the above, all have MHC class II molecules
B. T cells
138
What is the difference between normal microbiota and transient microbiota?
Normal microbiota permanently colonize the host
Transient microbiota may only be present for days, weeks, or months
139
Define the symbiotic relationship: Commensalism and give an example
One organism benefits while the other is unaffected/unharmed
Example: Staph Aureus in your nose
140
Define the symbiotic relationship: Mutualism and give and example
Both organisms benefit
Example: E. Coli in the gut benefit from rich nutrients, while they produce vitamins B & K for host benefit
141
Define the symbiotic relationship: Parasitism and give an example
One organism benefits at the expense of the other (host is harmed)
Example: H1N1
142
Define microbial antagonism
Competition between microbes
143
What are 3 ways that normal microbiota protect the host?
Occupying niches that pathogens might occupy
Producing acids
Producing bacteriocins
144
What are opportunistic pathogens?
Members of normal microbiota that produce disease under certain circumstances, such as when they are misplaced to an area they are not normally found
145
Where might you find the following normal microbiota:
Staphylococci (S. epidermidis)
Micrococci (M. luteus)
Diphtheroids (aerobic Corynebacterium xerosis and anaerobic Propionibacterium acnes)
Acinetobacter
Malassezia furfur
Skin
146
What is the predominant bacterium found on the conjunctiva of the eye?
Staphylococcus epidermidis
147
What normal flora might you find in the external ear?
Similar to skin flora as well as fungi
148
Where might you find the following normal microbiota:
S. mutans
Lactobacillus
Mouth
149
How do oral bacteria remain in place and what purpose do they serve as normal microbiota?
Oral bacteria such as S. mutans and Lactobacillus are very sticky, so they adhere to gums and teeth
They suppress pathogens by competitive inhibition in the upper respiratory system
150
What are the predominant normal microbiota in the nostrils?
Staphylococcus aureus and S. epidermidis
151
Where might you find the following gram positive normal microbiota:
Staphylococci (S. epidermidis)
Micrococci (M. luteus)
Diphtheroids
Streptococci (both alpha and beta-hemolytic)
Pharynx and trachea
152
Where might you find the following potentially pathogenic microbiota in low numbers:
Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenzae
Mycoplasmas
Nasopharynx
153
What areas of the body are normally free of microbiota?
Lower respiratory tract, kidneys, ureter, and bladder
154
Where would you find the largest and most diverse microbial population in the body, and what type of microbes live there?
Large intestine (colon)
Most of the microbes present are anaerobes
155
Where might you find the following microbiota:
```
E. Coli
Bacteroids
Fusobacterium
Lactobacillus
Enterococcus
Bifidobacterium
Enterobacter
Citrobacter
Proteus
Klebsiella
Candida (fungus)
```
Large intestine
156
What normal microbiota dominate the female genital tract, and what do they produce in order to keep anaerobic bacteria at bay?
Acid-tolerant lactobacilli, which produce H2O2
157
What type of bacteria (gram negative or gram positive) primarily colonize the gut?
Gram negative
158
What type of bacteria (gram negative or gram positive) typically colonize the respiratory tract, eyes, and ears?
Gram positive
159
Describe the function of type 1 T helper Cell (TH1)
Activates cells related to cell-mediated immunity: macrophages, Tc cells, and natural killer cells
160
Describe the function of type 2 T helper Cell (TH2)
Stimulates production of eosinophils, IgM, and IgE
161
Pathogenicity
Ability to cause disease
162
Primary pathogen
Causes disease by direct interaction with healthy host
163
Opportunistic pathogen
May be part of normal flora and causes disease when it has gained access to other tissue sites or host is immunocompramised
164
What is a zoonose and give examples
Infections passed from animal to human
SARS (bats), tuberculosis (horses, cattle), typhus fever (rats)
165
Natural environmental location in which the pathogen normally resides (can be animate or inanimate)
Reservoir
166
Organisms that spread disease from one host to another, for example: arthropods, mosquitos, and other biting insects
Vectors
167
What is the difference between signs and symptoms?
Signs are measurable/objective changes in body like blood pressure, pulse, temperature, etc.
Symptoms are subjective changes experienced by patient like nausea, fatigue, body aches, etc.
168
Period after pathogen entry, before signs and symptoms
Incubation period
169
Onset of signs and symptoms but not clear enough for diagnosis
Prodromal stage
170
Period of time where disease is most severe, ongoing signs and symptoms
Period of illness
171
Period of time when signs and symptoms of disease begin to disappear
Convalescence
172
Virulence factors
Allow a pathogen to outcompete host defense and resist their defenses
173
Virulence
Degree or intensity of pathogenicity; determined in part by the pathogen's ability to survive outside the host
174
Major virulence factors on large segments on chromosomal or plasmid DNA
Pathogenicity islands
175
What are common sequence characteristics of pathogenicity islands?
Insertion like sequences for mobility
G+C content different from bacterial genome
Several open reading frames
Can be spread through horizontal gene transfer
176
What is an example of a parenteral route portal of entry?
A break in the barrier system, such as a contaminated needle
177
If the portal of entry is the skin, what is the likely portal of exit?
The skin!
178
What are adhesins?
Special molecules that mediate adherance; they act as ligands which bind to receptors on host cells
Examples:
Glycocalyx
Fimbriae/pili
M protein
179
Streptococcus pyogenes causes a sore throat, what is its adhesion mechanism?
Protein F which binds to a protein residue on the host's upper respiratory tract cells
180
Penetration of an infectious agent can be active or passive, which type is the following?
Attack of the extracellular matrix and basement membranes of integuments and intestinal linings
Degrade carbohydrate-protein complexes between cells
Disrupt host cell surface
Active
181
Penetration of an infectious agent can be active or passive, which type is the following?
Spread through skin lesions, insect bites, or other wounds to deeper tissues involving the production of specific products and/or enzymes that promote spreading
Passive
182
Describe exotoxins in terms of their source, metabolic product, chemical make-up, ability to cause fever, ability to be neutralized by antitoxin, and magnitude of LD50
Source: mostly gram-positive
Metabolic product: by-products of growing cell
Chemistry: protein (soluble, heat-labile)
Fever? NO
Neutralized by antitoxin? YES
LD50: small (among the most lethal substances known)
183
Describe endotoxins in terms of their source, metabolic product, chemical make-up, ability to cause fever, ability to be neutralized by antitoxin, and magnitude of LD50
```
Source: gram-negative
Metabolic product: present in LPS of outer membrane
Chemistry: lipid
Fever? YES
Neutralized by antitoxin? NO
LD50: relatively large
```
184
Describe AB exotoxins
Composed of 2 subunits:
A subunit is responsible for toxic effect (active subunit)
B subunit is responsible for binding to specific target cell
185
What type of exotoxin stimulates ~30% of T cells of the immune system, causing overexpression of T cells and release of cytokines?
Superantigens
Result in failure of multiple host organs, allowing time for microbe to disseminate
186
What are the effects of biofilm development?
- may cause chronic infection
- increased virulence
- resistance to antibiotics or disinfectants
- "frustrates" phagocytes
187
What does the cell wall component: M protein do in terms of resisting host defenses?
Resists phagocytosis
188
What does the cell wall component: Opa protein do in terms of resisting host defenses?
Inhibits T helper cells
189
What does the cell wall component: Mycolic acid do in terms of resisting host defenses?
Mycolic acid is a waxy lipid that resists cellular digestion
190
How does the production of decoy proteins resist a host's defenses?
Decoy proteins bind available neutralizing antibodies
191
How to lengthened O-chains resists a host's defenses?
Lengthened O-chains prevent host detection or lysis
192
What component of a host cell may a pathogen use to eject itself from cell to cell?
Actin
193
What do capsules do in order to resist host defenses?
Prevent phagocytosis
194
What does the coagulase enzyme do in terms of resisting host defenses?
Coagulates fibrinogen which forms a wall so phagocytes can't get there
195
What do kinase enzymes do in terms of resisting host defenses?
Digestion of fibrin clots which is important for invasiveness (spreading to other tissues)
196
What does the hyaluronidase enzyme do in terms of resisting host defenses?
Hydrolyzes hyaluronic acid (found in connective tissue)
197
What does the collagenase enzyme do in terms of resisting host defenses?
Hydrolyzes collagen which allows pathogen to use amino acids
198
What do IgA protease enzymes do in terms of resisting host defenses?
Destroy IgA antibodies
199
What is phase variation?
Mutations that change antigenic sites or alter expression of antigens as a way of resisting host defenses
200
Are pathogens that are spread through direct contact thought to be more or less virulent?
Less
201
Are vector-borne pathogens thought to be more or less virulent?
Highly virulent in human host, but relatively benign in vector
202
Define tropism
Pathogen must make contact with the appropriate host tissue (determined by specific cell surface receptors) for infection to occur
203
Name the 5 main modes of pathogen transmission
1. Airborne
2. Contact
3. Vehicle
4. Vector-borne
5. Vertical
204
What is a vehicle in terms of vehicle transmission?
Inanimate materials or objects involved in pathogen transmission
205
What is a fomite in terms of vehicle transmission?
Common vehicles such as surgical instruments, bedding, and eating utensils
206
What are the 2 categories of vector-borne transmission?
External (mechanical) - pathogen on body of vector, no growth of pathogen during transmission
Internal - carried within a vector
207
Define vertical transmission
Occurs when unborn child acquires a pathogen from infected mother resulting in congenital infection
Examples: gonorrhea, herpes, german measles, toxoplasmosis
208
What two factors determine host susceptibility?
Defense mechanisms of host (innate vs. acquired immunity)
Pathogenicity of pathogen
209
All gram negative bacteria contain:
A. Exotoxins
B. Endotoxins
C. Siderophores
D. IgA protease
B. Endotoxins
210
C. Tetani causes the disease Tetanus by producing a(n)
A. Capsule
B. Endotoxin
C. Exotoxin
D. Enzyme
C. Exotoxin
211
Septic shock can result from using antibiotics to treat
A. Fungal infections
B. Viral infections
C. Protozoan infections
D. Gram negative bacterial infections
D. Gram negative bacterial infections
212
Arthropods provide a portal of exit for microbes in:
A. Skin
B. Blood
C. Respiratory tract
D. Genitourinary tract
B. Blood
213
Which of the following releases histamine?
A. Mast cells
B. Basophils
C. Plasma cells
D. Mast cells and basophils
D. Mast cells and basophils
214
Which of the following would you not find as normal flora in the nasopharynx?
A. Streptococcus pneumoniae
B. Escherichia coli
C. Neisseria meningitidis
D. Haemophilus influenza
B. Escherichia coli
215
Which of the following areas of the human body is/are NOT normally free of microorganisms?
A. Upper respiratory tract
B. Intestinal tract
C. Eyes
D. All of the choices
D. All of the choices
216
An inanimate object that may be contaminated with a pathogen is called a:
A. Vector
B. Fomite
C. Zoonose
D. Commensal
B. Fomite
217
True or false: Generally, exotoxins tend to be more heat stable than endotoxins
False
Exotoxins tend to be more heat LABILE because they're made up of protein
218
Antibody molecules that are produced by a single hybridoma clone are called:
A. Human antibodies
B. Monoclonal antibodies
C. Hybrid cells
D. Identical antibodies
B. Monoclonal antibodies
219
Why aren't culture based techniques used for parasites?
Because they need a host
220
What type of media do fungi prefer?
Acidic or low pH
221
What type of antibody is produced by a hybridoma cell as an "immortal" cancerous B cell fused with an antibody-producing normal B cell?
Hint: these recognize a single epitope
Monoclonal antibodies
222
What type of immunofluorescence involves unknown antigen added to antibody labeled with fluorescent dye resulting in visible fluorescence?
Direct, because the antibody is binding directly to the pathogen
223
What type of immunofluorescence involves known antigen tested in different serums to see if there is fluorescence that occurs?
Indirect
224
What is the best method for classification of bacteria and why?
Ribotyping (16S rRNA analysis)
Because the ribosome is stable; it has stayed the same despite transfer of material
225
What method is used for identification of bacteria based on number of plasmids and their molecular weight?
Plasmid fingerprinting
226
What type of serological test detects antigens from patient sample?
Direct
227
What type of serological test detects antibodies in patient serum?
Indirect
228
What would you assume had happened if a patient was not producing antibodies at one time, but two weeks later they were?
They underwent seroconversion
229
Would a mat formation or a pellet formation be an indicator of agglutination?
Mat
230
When using hemagglutination testing, what is the positive result and why?
A positive result would be NO agglutination, meaning that the antibodies are present and preventing agglutination
231
What is the indicator for complement fixation testing?
RBCs (hemolysis)
232
Is complement fixation test direct or indirect?
Indirect, because looking for the presence of antibodies
233
What is a positive result in the complement fixation test?
No hemolysis, because the complement is tied up in the antigen-antibody reaction
234
What is the indicator for the ELISA test?
Peroxidase enzyme, reaction is visualized by addition of chromogen (color change)
(ELISA = Enzyme-Linked Immunosorbent Assay)
235
What is adsorbed to the bottom of the well in the first step of a direct ELISA? What about an indirect ELISA?
Direct ELISA: antibody is adsorbed to the well
Indirect ELISA: antigen is adsorbed to the well
236
What occurs in the fluorescent-antibody technique?
Antibodies are linked to fluorescent dye
237
What indicates a positive result during a neutralization test?
Indicator is cell damage; if antitoxins bind, they will be neutralized and we will see undamaged cells which is a positive result
238
Sporadic disease
Occurs occasionally and at irregular intervals
239
Endemic disease
Maintains a relatively steady low-level frequency at a moderately regular interval
240
Hyperendemic disease
Gradual increase in occurrence frequency above endemic level but not to epidemic level
241
Epidemic
Sudden increase in frequency above expected number
Index case is the first case in an epidemic
242
Pandemic
Increase in disease occurrence within large population over wide region (usually worldwide)
243
Outbreak
Sudden, unexpected occurrence of disease usually in a focal or limited segment of population
244
Morbidity rate
Incidence rate measuring number of new cases in a specific time period per unit of population
245
Prevalence rate
Total number of individuals infected at one time (depends on both incidence rate and duration of illness)
246
Mortality rate
Number of deaths from a disease per number of cases of the disease
247
Communicable disease
A disease that is spread from one host to another (a contagious disease is one that is EASILY spread)
248
Noncommunicable disease
A disease that is not transmitted from one host to another (for example: botulism)
249
Acute disease
Symptoms develop rapidly
250
Chronic disease
Disease develops slowly
251
Subacute disease
Symptoms between acute and chronic
252
Latent disease
Disease with a period of no symptoms when the causative agent is inactive
253
What is a nosocomial infection and what is the most common type?
Hospital acquired infection often due to normal flora of patient or caregiver acting as opportunistic pathogens
Most common is urinary tract infection
Others include: surgical site infections, bloodstream infections (IVs), pneumonia (artificial airways)
254
What are the three possible sources of nosocomial infections?
Endogenous: brought into hospital by patient or acquired when patient is colonized after admission
Exogenous: microbiota other than the patient's
Autogenous: caused by an agent derived from microbiota of patient despite whether it became a part of the patient's microbiota following admission
255
What is the #1 way to control nosocomial infections?
Education of healthcare professionals and frequent handwashing
256
What type of immunity is stimulated by vaccinations/immunizations?
Artificially acquired active immunity
257
What type of organism is contained in an attenuated vaccine?
Live but avirulent
258
What type of organism is contained in an inactivated vaccine?
Dead
259
What is a disadvantage to the attenuated polio vaccine given in other countries?
It is possible to get vaccine-derived polio due to reversion mutation from live organism
260
Define adjuvant and give the most commonly used one
Substance mixed with antigens in vaccines to enhance the rate and degree of immunization
One of the most common is Aluminum
261
What is a DNA vaccine?
DNA is directly introduced into host cell via gene gun, where DNA is taken into nucleus and pathogen's DNA fragment is expressed so that host immune system can respond
262
What are some characteristics that favor the use of biological agents as weapons?
Invisible, odorless, tasteless
Difficult to detect
Take hours/days before awareness that they have been used
Fear and panic associated with anticipation that they were used
263
What are two possible key indicators of a bioterrorism event?
Sudden increased numbers of sick people, especially with unusual diseases for that place and/or time of year
Sudden increased number of zoonoses, diseased animals, or vehicle borne illnesses
264
What is the most common type of nosocomial infection?
A. Lower respiratory infections
B. Postoperative infections
C. Bacteremia infections
D. Urinary tract infections
D. Urinary tract infections
265
Which of the following measures is NOT used to prevent nosocomial infections?
A. Aseptic technique
B. Frequent handwashing
C. Increased use of antibiotics
D. Education of staff
C. Increased use of antibiotics
266
What organism is the most important reservoir for the Borrelia burgdorferi?
A. Tick
B. Rabbit
C. Squirrel
D. Field mouse
D. Field mouse
267
In what stage of syphilis do gummas develop?
A. Primary
B. Secondary
C. Tertiary
D. Latent
C. Tertiary
268
Which urinary tract bacteria can cause headaches, fever, and possible kidney failure as a complication?
A. Escherichia coli
B. Staphylococcus saprophyticus
C. Leptospira interrogans
D. Neisseria gonorrhoeae
C. Leptospira interrogans
**E. Coli can cause UTIs but it is not a urinary tract bacteria
269
What class of pathogen lacks a cell wall, is the smallest bacteria capable of self-reproduction, operates as an obligate intracellular parasite, contains less than 1000 genes, and grows on agar with "fried-egg" appearance?
Mycoplasmas
270
Describe metabolism of mycoplasmas
Relies on host cells; they are chemoorganotrophs
- most have urea transporter for catabolism
- utilize an ATPase to generate a gradient driving ATP synthesis through urea hydrolysis
271
What are two important mycoplasma pathogens?
Mycoplasma pneumoniae - primary atypical pneumonia in humans
Ureaplasma urealyticum - UTIs, premature birth, neonatal meningitis, and pneumonia
272
Describe Phylum Chlamydiae
Gram-negative, nonmotile, coccoid
Obligate intracellular parasites with unique developmental cycle
273
Describe Chlamydial metabolism
Cannot catabolize carbs
Cannot synthesize ATP or NAD+
Reticular bodies have biosynthetic capabilities in host
Elementary bodies seem to be dormant forms
274
Describe the developmental cycle of Genus Chlamydia
EB attaches to host cell
RB reproduction by binary fission
Differentiate back into EB, lyses cell
275
Describe Phylum Spirochaetes
Gram-negative, chemoheterotrophic
Long and slender with flexible helical shape
Creeping motility due to axial filaments (corkscrew)- good for viscous environments
Symbiotic with termites, mollusks, mammals
276
What is the causative agent of Lyme Disease?
Borrelia burgdoferi
277
What is the primary reservoir and vectors associated with Lyme Disease?
Primary reservoir: field mouse
Vector: deer tick
278
What are the three stages of Lyme Disease?
Localized: Bull's eye rash
Disseminated: irregular heartbeat, encephalitis
Late stage: arthritis and demyelination of neurons
279
How is Lyme Disease diagnosed?
Serological testing (Lyme ELISA or Western blot)
Isolation of spirochete from patient (fluorescence)
Detection of Borrelia DNA (PCR)
280
What is the primary treatment for Lyme disease?
Antibiotic therapy - must be given early to be effective
281
Describe Relapsing Fever in terms of etiological agent, reservoir, and vector
Causative agent: Borrelia spp. (Spirochete)
Reservoir: rodents
Vector: ticks
*Successive relapses are less severe
282
What is the causative agent of Syphilis and how does it invade a host?
Treponema pallidum which invades mucosa or through skin breaks
283
What are two variations of Syphilis (in terms of transmission)?
Venereal: sexually transmitted
Congenital: acquired in utero
284
What are the 3 stages of Syphilis characterized by?
Primary: chancre (small, painless, reddened ulcer) at infection site that contains spirochetes
Secondary: highly variable skin rash + palms & soles
Tertiary: formation of gummas (degenerative lesions) in skin, bone, and nervous system
285
What are some methods for diagnosing Syphilis?
Taking clinical history, microscopic examination, and serology
Direct diagnosis by staining with fluorescent-labeled monoclonal antibodies
Indirect rapid screening and confirmation testing
286
What is the primary treatment for Syphilis?
Antibiotic therapy - must be given early on for maximum effectiveness
287
Describe Leptospirosis in terms of causative agent, reservoir, and transmission
Causative agent: Leptospira interrogans
Reservoir: dogs and rats
Transmission: skin/mucosal contact from urine-contaminated water
288
What are the symptoms and possible complications of Leptospirosis?
Headaches, muscle aches, fever
Possible complications: kidney failure, meningitis, liver failure, respiratory distress (bleeding in lungs), or death
289
How is Leptospirosis diagnosed?
Serological testing: growing bacteria from blood sample, finding antibodies or microbial DNA in the blood
290
What is the treatment for Leptospirosis?
Doxycycline
291
Describe Genus Rickettsia
Very small, gram-negative, non-flagellated, diverse morphology
Most species are parasitic, growing in vertebrate erythrocytes, macrophages, or vascular endothelial cells. May also live in blood-sucking arthropods
292
Which type of pathogen might the mitochondria have originated in?
Rickettsia
293
Describe Rickettsia metabolism
They lack a glycolytic pathway, must oxidize glutamate and TCA cycle intermediates
Typically take up and use ATP from host cell
294
Describe Epidemic typhus in terms of causative agent, reservoir, vector, and transmission
Causative agent: Rickettsia prowazekii
Reservoir: rodents
Vector: lice
Transmission: louse feces rubbed into bite wound
295
Back pain, delirium, high fever (40 C), joint pain, low blood pressure, light sensitivity, rashes, headaches, and muscle pain are symptoms of which type of Typhus?
Epidemic typhus
296
Describe endemic murine typhus in terms of causative agent, reservoir, and vector
Causative agent: Rickettsia typhi
Reservoir: rodents
Vector: flea
297
Abdominal pain, back ache, dull red rash (begins in middle of body and spreads), extremely high fever (41 C), hacking dry cough, severe headaches, joint pain, muscle pain, and vomiting are all symptoms of which type of Typhus?
Endemic murine typhus
298
Describe the reproduction of Rickettsia
Enters host by phagocytosis
Escapes the phagosome
Reproduces in cytoplasm
Host cell bursts
299
What is the causative agent of Rocky Mountain Spotted Fever?
Rickettsia rickettsii
300
What are the two primary ways that Rocky Mountain Spotted Fever is transmitted?
Transmitted by ticks by:
Transovarian passage: transmission of bacteria from generation to generation of ticks through their eggs
Passage by tick feeding or by defecation of tick and rubbed into skin
301
What two types of cells do Rickettsias reproduce in?
Endothelial cells and macrophages
302
In which two diseases does the rash appear on the palms and soles?
Rocky Mountain Spotted Fever and Syphilis
303
Vasculitis (destruction of blood vessels) in heart, lungs, or kidneys
Sudden onset of headache, high fever, chills, and skin rash are possible signs/symptoms of what disease?
Rocky Mountain Spotted Fever
304
How is Rocky Mountain Spotted Fever diagnosed?
Observation of signs and symptoms and serological testing
305
How is Rocky Mountain Spotted Fever usually treated/controlled?
Antibiotic therapy (Doxycycline) and symptomatic/supportive therapy
Tick control and avoidance of ticks
306
What type of bacteria are nonmotile, gram-negative cocci that most often occur in pairs with adjacent sides flattened? They also may have capsules and fimbriae
Neisseria
307
What two diseases are caused by variations of Neisseria?
Gonorrhea and Meningitis
308
Meningitis may be an endogenous infection (normal biota); How might you diagnose meningitis?
A bacterial form may be diagnosed by gram stain of cerebrospinal fluid which may or may not work
309
How is meningitis transmitted?
Respiratory droplets
310
Initial respiratory illness or sore throat followed by vomiting, headache, lethargy, confusion, and stiffness in the neck and back may be signs of what disease?
Meningitis
311
What are the virulence factors of Neisseria Meningitis?
Capsules and fimbriae
312
What bacteria causes gonorrhea?
Neisseria gonorrhoeae
313
What are the virulence factors associated with gonorrhea?
Fimbriae and Opa proteins which prevent CD4 T cell proliferation
314
What condition, when left untreated, may lead to Endocarditis, meningitis, arthritis, or ophthalmia neonatorum?
Gonorrhea
315
Which pathogen blocks C3 of the complement activation and exhibits antigenic variation in producing soluble pilli?
Neisseria gonorrhoeae
316
What are the symptoms of gonorrhea?
Men: painful urination and discharge of pus
Women: few symptoms but possible complication of PID
317
How would you diagnose gonorrhea?
Gram stain, ELISA, or PCR
318
What treatment is typically used for Gonorrhea?
Fluoroquinolones
319
Which type of bacteria is gram-negative coccobacilli, some with capsules that are nonmotile
Genus Bordetella
320
Which disease involves toxins producing nitric oxide that may lead to stopping protein synthesis (such as cytokine production)
Pertussis
321
What are the clinical manifestations of Pertussis?
7-14 day incubation with initial coldlike symptoms/inflamed mucous membranes
Followed by prolonged coughing sieges with inspiratory whoop
permanent or long-lasting immunity develops
322
What are the 3 stages of Pertussis?
Stage 1: Catarrhal stage, like common cold
Stage 2: Paroxysmal stage -- violent cough
Stage 3: Convalescence stage
323
How would you diagnose Pertussis?
Bacterial culture, fluorescent antibody staining, and serological testing
324
Which type of bacteria produces a characteristic blue/green discharge on surgical wounds or burn wounds?
Pseudomonas
325
What is the causative agent of Legionnaire's disease (and Pontiac Fever)
Legionella pneumophilia - a fastidious gram negative rod harbored by free-living amoeboae and ciliated protozoa
326
Which type of bacteria's life cycle involves replicative form differentiating into mature intracellular form (infectious/dormant form) which is resistant to antibiotics?
Genus Legionella
327
Legionnaire's disease produces what to cause localized tissue destruction?
Cytotoxic exoprotease
328
What are the clinical manifestations of Legionnaire's disease?
Fever, cough, headache, neuralgia, and bronchopneumonia
These may be severe in immunocompromised patients
329
What is one important aspect of controlling Legionnaires disease?
Eliminating nosocomial spread
330
What virulence factor contributes to Legionnaire's resistance to antibiotics?
Beta-lactamase
331
What is the causative agent of Cholera?
Vibrio cholerae - comma shaped gram-negative bacteria acquired by ingesting food or water contaminated by fecal matter from patients or carriers
332
What is a natural reservoir of Cholera?
Shellfish
333
Which disease involves production of rice-water stools and rushes of peristalsis?
Cholera
334
How would you diagnose Cholera?
Culture from feces with subsequent identification by agglutination reactions
335
True or False: M protein enhances the virulence of streptococcus by preventing phagocytosis
True
*M proteins function in attachment AND prevention of phagocytosis
336
A nosocomial infection is:
A. Always caused by medical personnel
B. Always caused by pathogenic bacteria
C. Always present, but is not observed in times of hospitalization
D. Acquired during the course of hospitalization
D. Acquired during the course of hospitalization
337
True or False: An endemic disease is constantly present in a population
True
338
Which item is from the patient in a direct ELISA test?
A. Substrate for the enzyme
B. Antigen
C. Antihuman immune system
D. Antibodies against the antigen
B. Antigen
339
Purified protein from Bordetella pertussis is used in a(n):
A. Attenuated whole-agent vaccine
B. Nucleic acid vaccine
C. Subunit vaccine
D. Toxoid vaccine
C. Subunit vaccine
340
What is the function of an O antigen?
LPS
341
What is the function of an H antigen?
Flagellar proteins
342
What is the function of a K antigen?
Capsule proteins
343
What are some virulence factors of pathogenic E.coli?
Fimbriae for attachment to intestinal cells
Production of toxins
Aggregation
344
What are the symptoms, diagnosis, and treatment for Enterotoxigenic, enteroinvasive, or enteraggregative E.coli (traveler's diarrhea)?
Symptoms: watery diarrhea
Diagnosis: isolation of bacteria
Treatment: oral rehydration
345
Is traveler's diarrhea an infection or an intoxication?
Infection via endotoxin
346
What are the symptoms, diagnosis, and treatment for Siga-toxin-producing E.coli?
Symptoms: Shigella-like dysentary, hemorrhagic colitis, and hemolytic uremic syndrome
Diagnosis: isolation of bacteria
Treatment: quinolones; cephalosporins
347
Is Shiga-toxin-producing E.coli (STEC) an infection or an intoxication?
Infection via Shiga exotoxin
348
Which type of E.Coli produces one or both enterotoxins responsible for diarrhea and is distinguished by its heat stability (ST and LT?)
Enterotoxigenic E.coli (ETEC)
349
Which type of E.Coli multiplies within the intestinal epithelial cells and may produce a cytotoxin and an enterotoxin?
This type also has invasiveness gene on large plasmid which can be determined by plasmid fingerprinting
Enteroinvasive E.coli (EIEC)
350
Which type of E.coli causes effacing lesions caused by destruction of brush border microvilli on intestinal epithelial cells?
Enterohemorrhagic E.coli (EHEC)
351
What is the reservoir associated with Salmonella?
Poultry and cattle
352
What are possible symptoms, diagnosis, and treatment of salmonellosis?
Symptoms: Abdominal pain, cramps, diarrhea, nausea, vomiting, and fever
Diagnosis: isolation of organism from food or patient's stools
Treatment: fluid and electrolyte replacement; good food handling practices, proper refrigeration, adequate cooking
353
Name the pathogen, symptoms, diagnosis, and treatment of Typhoid Fever due to salmonella
Pathogen: Salmonella typhi (infection via endotoxin)
Symptoms: high fever, significant mortality
Diagnosis: isolation of bacteria; serotyping
Treatment: quinolones, cephalosporins
354
What is the reservoir for shigellosis?
Humans
355
What are some virulence factors in Shigellosis?
Endotoxin, exotoxins (Shiga toxin), type III secretion system for delivery into epithelial cells
356
Name the symptoms, diagnosis, and treatment of Shigellosis
Symptoms: watery stools often containing blood, mucus, and pus, tissue damage, dysentary
Diagnosis: biochemical characteristics; serology
Treatment: antibiotics (quinolones), prevention by good personal hygiene and clean water supply
357
What is the reservoir and vector of yersinia pestis (plague)?
Reservoir: rats, ground squirrels, and prairie dogs (rodents)
Vector: fleas
358
What are the 3 types of plague?
Bubonic - bacterial growth in blood and lymph
Septicemia plague - septic shock due to bloodstream infection
Pneumonic plague - bacteria in the lungs (high mortality rate)
359
What are virulence factors associated with the plague?
Proliferation in phagocytes, type III secretion systems deliver yersinal outer membrane proteins which shut down cell defense mechanisms
360
What are the symptoms, diagnosis, and treatment for the plague?
Symptoms: subcutaneous hemorrhage, fever, buboes
Diagnosis: made in reference labs which use direct microscopic examination, culture, serological tests, and PCR
Treatment: antibiotics, ectoparasite and rodent control, immunizations for those at risk
361
Describe Campylobacter fetus in terms of its effects on animals vs. humans
Causes reproductive disease and abortions in cattle and sheep
Septicemia and enteritis in humans
** may also lead to Guillain Barre syndrome triggered in molecular mimicry
362
Describe the diagnosis and treatment of Campylobacter jejuni
Diagnosis: culture in low oxygen, high CO2 atmosphere
Treatment: symptomatic/supportive therapy, antibiotics in severe cases
363
What virulence factor in Helicobacter pylori allows it to grow at its optimal pH?
What are other virulence factors?
Secretion of urease which converts urea to ammonia and CO2, which raises pH to 4.5
Other virulence factors: surface fimbriae (adhesins), inflammation due to proteases, phospholipases, cytokines, and cytotoxins
364
How is Helicobacter peptic ulcer disease diagnosed and treated?
Diagnosis: urea breath, bacterial culture
Treatment: antimicrobial drugs
365
Bacillary dysentery is caused by:
A. Staphylococcus
B. Shigella
C. Salmonella
D. Clostridium
B. Shigella
366
What is the main reservoir for Yersinia pestis?
A. Deer
B. Rodents
C. Small mammals
D. Rabbits
B. Rodents
367
C. tetani causes the disease Tetanus by producing a(n):
A. Capsule
B. Endotoxin
C. Exotoxin
D. Enzyme
C. Exotoxin
368
Which urinary tract bacterium can cause headaches, muscle aches, fever, and possible kidney failure as a complication?
A. Escherichia coli
B. Staphylococcus saprophyticus
C. Leptospira interrogans
D. Neisseria gonorrhoeae
C. Leptospira interrogans
369
What is the etiological agent for the disease that has catarrhal, paroxysmal, and convalescence stages?
A. Borrelia
B. Streptococcus
C. Mycobacterium
D. Bordetella
D. Bordetella
370
List the Etiological agent, disease, virulence factors/ unique characteristics for Mycoplasma
Etiological agent: Mycoplasma pneumonia or Ureaplasma urealyticum
Disease: atypical pneumonia
Virulence factors: lack cell walls, contain sterols**, use gliding motility and have adhesion molecules
371
List the Etiological agent, the disease, the unique characteristics and the virulence factors of Chlamydia
Etiological agent: Chlamydia
Disease: Chlamydia
Characteristics: Gram neg cocci, obligate intracellular parasite, has a unique developmental cycle:
-EB (elementary body): the infectious/ dormant form
-RB (reticulate body): reproduction by binary fission
Virulence factor: endotoxin
372
List the etiological agent, disease, morphology, vector, reservoir, and virulence factor for Borrelia
Etiological agent: Borrelia burgdoferi
Disease: Lyme Disease
Morphology: Spirochete
Vector: tick
Reservoir: Rodents
Virulence factor: antigenic variation
373
List the Etiological agent, disease, reservoir, and morphology of treponema
Etiological agent: Treponema pallidum
Disease: Syphillis
Reservoir: humans
Morphology: spirochete
374
List the Etiological agent, reservoir(s), mode of transmission, characteristics and symptoms of leptospira
Etiological agent: Leptospira interrogans
Reservoir: Dogs and Rats
Transmission: skin/ mucosal contact from urine contaminated water
Symptoms: Headahces, muscular aches, fever, kidney failure (possible). Can lead to meningitis, liver failure, respiratory distress
Characteristics: Gram neg spirochete
375
List the Etiological agent, the disease and stages, the characteristics, and the virulence factors of Bordetella
EA: Pertussis
Disease: Whooping cough
Stages: Stage 1: Catarrhal, Stage 2: Paroxysmal, Stage 3: Convalescence
Characteristics: gram neg coccobacilli
Virulence factors: capsule, Pertussis toxin (ADP ribosylation=> mucous)
376
List the Etiological agent, symptoms, disease, vector, virulence factors and characteristics of Rickettsia
EA: Rickettsia rickettsi
Disease: Rocky Mountain spotted fever
Symptoms: sudden onset of head ache, vasculitis, rash on palms and soles
Vector: ticks
Virulence factors: intracellular parasites, escape phagosome
377
List the Etiological agent, the disease, and the main symptom, and vector with regards to epidemic or endemic Rickettsia
EA: prowazekii (epidemic), typhi (endemic)
Disease typhus fever
Symptom: High fever
Vector(s): lice and fleas
378
List the Etiological agent(s), characteristics, and virulence factors associated with Neisseria
EA: Neisseria gonorrhoeae and Neisseria meningitis
Chacrteristics of Neisseria: gram neg cocci
Virulence factors of Neisseria gonorrhea: fimbrae, opa protein, capsule, S pili
Of Neisseria meningitis: capsule and fimbrae
379
List the eitiological agent, symptoms/ causes, chacrteristics, and virulence factors of pseudomonas
EA: pseudomonas aeruginosa
Symptoms: post-burn infections, otitis externa
Chacrteristics: Pyocyanin produces blue green pus, gram negative, one or more polar flagella
Virulence factors: efflux pumps
380
List the etiological agent, disease, chacrteristics, reservoirs, and normal host of Legionella
EA: legionella pneumophila
Disease: Legionnaires disease
Characteristics: gram neg, Reproduction cycle: replicative form (non virulent/ replicative) and the Mature Intracellular Form (virulent/ dormant)
Virulence: Mature intracellular form (virulent and dormant)
Normal host: Amoeba
Reservoirs: Environmental reservoirs: soil, aquatic, AC systems, Shower stalls
381
List the Etiological agent, characteristics, reservoir/ carriers, virulence factors, and symptoms of the disease of Vibrio
EA: V. Cholerae ( causes cholera)
V. Parahaemolyticus (causes gastroenteritis)
Characteristics: gram neg, CURVED ROD,
Virulence factors: cholera toxin, adheres to small intestine and mucosa.
Carriers: contaminated foods and water
Symptoms of cholera: Rice water stool
382
List the etiological agent, characteristics, symptoms and virulence factors of shigella
EA: Shigella spp.
