C8 - Host Microorganisms Interactions (Part 1) Flashcards
1
Q
→ growth and multiplication of microorganisms that cause damage to the host
A
Infection
2
Q
→bodily invasion of pathogenic microorganisms that reproduce, multiply and then cause disease through local injury, toxin secretion or An-Ab reaction to the host
A
Infection
3
Q
→caused by microorganism from the microbiota of the host
A
Autogenous Infection
4
Q
→ result of medical treatment or procedure
A
Iatrogenic infection
5
Q
→affects immunocompromised host
A
Opportunistic Infection
6
Q
→hospital-acquired infection
A
Nosocomal infection
7
Q
Types of Infections
A
a. Autogenous
b. Iatrogenic
c. Opportunistic
d. Nosocomal
8
Q
4 common types of INFECTION
A
- UTI
- Lung Infection (Pneumonia)
- Surgical site Infection
- Blood stream Infection
9
Q
Predisposing factors
A
a. Wide variety of microbes in the hospital environment
b. Immunocompromised patient
c. Chain of transmission (direct or Indirect)
10
Q
Chain of Transmission EXAMPLES
A
✓ Health worker to patient
✓ Patient to patient
✓ Use of fomites(catheters, needles, dressings, beds)
✓ Airborne transmission
✓ Vector-borne
11
Q
Airborne transmission (TB & Pertussis)
A
TB: < 5um, Pertussis: > 5um
12
Q
cornerstone of modern infection control program
A
Handwashing
13
Q
TYPES OF INFECTION ACCORDING TO HOST DISTRIBUTION
A
- Local Infection
- Focal Infection
- Systemic Infection
14
Q
signs and symptoms are confined in one area; wounds, boils, abscesses
A
Local Infection
15
Q
starts as a focal infection before spreading to other parts of the body
A
Focal Infection
16
Q
spread throughout the body through the blood or lymph
A
Systemic Infection
17
Q
presence of bacteria in blood; highest concentration of bacteria in blood occurs before the fever spikes
A
Bacteremia
18
Q
active multiplication of bacteria in blood
A
Septicemia
19
Q
pus-producing organisms repeatedly invade the bloodstream and become localized at different parts of the body
A
Pyremia
20
Q
presence of toxins in the blood
A
Toxemia
21
Q
Classification of Disease According to Occurrence
A
- Sporadic
- Endemic
- Epidemic
- Outbreak
- Pandemic
22
Q
disease that occurs occasionally
A
Sporadic
23
Q
a disease constantly present at some rate of occurrence in a particular location
A
Endemic
24
Q
a larger than normal number of diseased or
infected individuals in a particular location
A
Epidemic
25
a larger than normal number of diseased or infected individuals that occurs over a relatively short period
Outbreak
26
an epidemic that spans the world
Pandemic
27
a person who carries the etiologic agent but shows no apparent signs or symptoms of infection or disease
Carrier
28
harbors the microorganism temporarily for a few days or weeks
Causal/Acute/Transient Carrier
29
remain infected for a relatively long time, sometimes throughout its entire life (Typhoid Bacillus)
Chronic Carrier
30
recovered from infection but continuous to harbour larger numbers of the pathogen
Convalescent Carrier
31
overt clinical case of the disease
Active carrier
32
PHASES OF INFECTIOUS DISEASES
- Incubation Period
- Prodromal Period
- Clinical or Illness Period
- Decline Period
- Convalescence or the Period of Recovery
33
time between the exposure to a pathogenic organism and the onset of symptoms
Incubation Period
34
appearance of signs and symptoms period
Prodromal Period
35
peak of characteristic signs and symptoms
Clinical or Illness Period
36
signs and symptoms begin to subside as the host’s condition improves
Decline Period
37
host is recuperating towards full recovery
Convalescence or the Period of Recovery
38
a microorganism responsible for causing infection or infectious disease
Causative/Etiologic Agent
39
organism capable of producing disease
Pathogen
40
a quantitative measure of the degree of pathogenecity of a particular microorganism
Virulence
41
microorganism that does not cause disease; may be part of the normal flora
Nonpathogenic
42
an agent capable of causing disease only when the host's resistance is impaired (PAE, Stenotrophomonas maltophilia)
Opportunistic pathogen
43
means by which etiologic agents are brought in contact with the human host (e.g. infected blood, contaminated water, insect bite)
Mode of Transmission
44
a non-living entity that is contaminated with
the etiologic agent and as such is the mode of
transmission for that agent
Vehicle/Fomite
45
a living entity (animal, insect, or plant) that transmits the etiologic agent
Vector
46
an animal or plant that harbors or nourishes another organism
Host
47
an organism which is dependent on another
organism for food and shelter
Parasite
48
any type of epidemiologic investigation that involves data collection for characterizing circumstances surrounding the incidence or prevalence of a particular disease or infection
Surveillance
49
the state of disease and its associated effects on the host
Morbidity
50
death resulting from disease
Mortality
51
laboratory-based characterization of etiologic agents designed to establish their relatedness to one another during a particular outbreak or epidemic
Strain typing
52
origin of the etiologic agent or location from which they disseminate (e.g., water, food, insects, animals, other humans)
Reservoir
53
the etiologic agent responsible for an epidemic or outbreak originates from a single source or reservoir
Common Source
54
association of two organisms living in close
proximity
Symbiosis
55
refers to a mutually beneficial relationship
between two species
Mutualism
56
a relationship wherein the parasite derives benefits from the host without causing injury or harm to the host
Commensalism
57
a relationship whereby one organism derives
benefits at the expense of another
Parasitism
58
ability of the organism to produce disease
Pathogenicity
59
large groups of genes that are associated with pathogenicity and are located on the bacterial chromosome
Pathogenicity Island
60
the ability of the organism to enter host tissues, multiply, and spread faster
Invasiveness
61
ability of the organism to produce toxins
Toxigenicity
62
non-poisonous forms of toxins which can be used for vaccination
Toxoid
63
Toxoid Preparation
✓ By aging
✓ By exposure to heat
✓ By exposure to 50% alcohol, formaldehyde, and dilute acids
64
General Stages of Microbial-Host Interaction
Physical encounter between host and microorganism → Microorganism colonization of host surface(s) → Microorganism entry, invasion, and dissemination → Outcome
65
microorganisms that are commonly found on or in body sites of healthy persons
Normal, Usual, or Indigenous Flora
66
microorganisms that colonize an area for months or years
Resident Microbial Flora
67
microorganisms that are present at a site temporarily represent
Transient Flora
68
Microorganism's presence depends on:
✓physiologic factors of temperature
✓moisture
✓presence of certain nutrients and inhibitory substances
69
Microbial Flora ROLE!!!
➢Provide a first line of defense against microbial pathogens
➢Assist in digestion and absorption of nutrients; also synthesis of Vitamin K
➢Play a role in toxin-degradation
➢Contribute to maturation of the immune system
70
How does MICROBIAL FLORA provides first line of defense?
✓competition for receptors or binding sites on host cells
✓competition for nutrients
✓mutual inhibition by metabolic or toxic products
✓mutual inhibition by antibiotic materials or bacteriocins
71
Different Body Site of Microbial Flora
a. Usual Flora of the Skin
b. Usual Flora of the Mouth
c. Usual Flora of the Respiratory Tract
d. Usual Flora of the GIT
e. Usual Flora of the Genitourinary Tract
72
**_____________ in vagina is a part of the normal flora but are important colonizers
Escherichia coli
73
ability of a microbe to produce disease in a
susceptible individual
Pathogenicity
74
→are organisms recognized to cause disease in healthy immunocompetent individuals
True pathogens
75
Example of True Pathogens
Yersinia pestis
Bacillus anthracis
76
→cause disease if the host is immunocompromised
Opportunistic pathogens
77
Example of Opportunistic Pathogen
E. coli
78
Conditions Compromising Host Defenses
Foreign bodies
Alcoholism
Burns
Hematoproliferative disorders
Cystic fibrosis
Immunosuppression
79
Examples of Foreign Bodies that can compromise host defenses
catheters, shunts, prosthetic heart valves
80
Foreign bodies - Organisms
Staphylococcus epidermidis
Propionibacterium acnes
Aspergillus spp.
Candida albicans
Viridans streptococci
Serratia marcescens
Pseudomonas aeruginosa
81
Alcoholism - Organisms
Streptococcus pneumoniae
Klebsiella pneumoniae
82
Burns - Organisms
Pseudomonas aeruginosa
83
Hematoproliferative disorders - Organisms
Cryptococcus neoformans
Varicella-zoster virus
84
Cystic fibrosis - Organisms
Pseudomonas aeruginosa
Burkholderia cepacia
85
Immunosuppression (drugs, congenital disease) - Organisms
Candida albicans
Pneumocystis jirovecii (carinii)
Herpes simplex virus
Aspergillus
Diphtheroids
Cytomegalovirus
Staphylococcus spp.
Pseudomonas spp.
85
→relative ability of a microorganism to cause disease or the degree of pathogenicity
→measured by the numbers of microorganisms necessary to cause infection in the host
Virulence
86
Microbial Virulence Factors
a. inhibiting phagocytosis
b. Facilitating adhesion to host cells or tissues
c. enhancing intracellular survival after phagocytosis
d. damaging tissue through the
e. production of toxins and extracellular enzymes
87
→highly virulent
→mask the cell surface structures that are recognized by receptors on the surface of the phagocytic cell
→inhibits the activation of complement by masking structures to which complement proteins bind
Capsule
88
Example of Microorganisms that uses Capsule to resist Phagocytosis
S. pneumoniae
H. influenzae
N. meningitidis
K. pneumoniae
S. typhi
P. aeruginosa
B. anthracis
Y. pestis
89
→interfering with the binding of the host’s antibodies to the surface of the organism
→ binds to the Fc portion of IgG preventing opsonization and phagocytosis by turning the antibody around on the surface
Protein A
90
Protein A is found in the cell wall of
Staphylococcus aureus
91
CELL WALL PROTEINS
- M protein
- Fimbriae and Outer Membrane Protein
- Mycolic Acid
- Antigenic variation
92
→heat resistant and acid resistant protein, mediates attachment to host epithelial cell and helps resist phagocytosis; overcome by antibodies produced this protein
M protein
93
Neisseria gonorrhoeae - Cell Wall Proteins
Fimbriae and Outer Membrane Protein
Antigenic variation
94
→M. tuberculosis; resist digestion during phagocytosis; the bacteria can even multiply inside macrophages
Mycolic acid
95
→produced by Streptococci
→lyse red blood cells and induce toxic effects on WBC
Hemolysins
96
→realesed by pathogenic staphylococci
→cause lysosomal discharge into cell cytoplasm
Leukocidins
97
→ Staphylococcal leukocidin
→lethal to leukocytes and contributes to the
invasiveness of the organism
Panton-Valentine
98
→cell surface structures that mediate
attachment
Adhesins
99
Main Adhesins in Bacteria:
1. Fimbriae (pili)
2. Surface polysaccharides
100
→enable bacteria to adhere to host cell surfaces, offering resistance by attachment to target cells, increasing the organism’s colonizing ability
Fimbriae (pili)
101
→ use lactoferrin as a source of iron
Meningococci
102
→produce an IgA protease that degrades the IgA found at mucosal surfaces
H. influenzae, N. gonorrhoeae, and N. meningitidis
103
→circumvent host antibodies by shifting key cell surface antigens
Borrelia spp.
104
→microorganisms able to multiply intracellularly
Chlamydia, Mycobacterium, Brucella, and Listeria
105
→ ability to penetrate and grow in tissues
Invasion
106
→ disease or organisms spread to distant sites Example: Salmonella spp.
Dissemination
107
highly invasive organism that may not disseminate
Clostridium perfringens
108
→poisonous substances produced by organisms that interact with host cells, disrupting normal metabolism and causing harm
Toxins
109
→soluble substances that liquefy the hyaluronic acid of the connective tissue matrix, helping to spread bacteria in tissues, promoting the dissemination of infection
Proteases and Hyaluronidases
110
→breaks down collagen, which forms the connective tissue of muscles and other body organs and tissues
Collagenase
111
→hydrolyzes hyaluronic acid, a type of
polysaccharide that holds together certain cells of the body, particularly cells of the connective tissue helping the organism spread from its initial site of infection
Hyaluronidase
112
can cause cellulitis
Streptococcus pyogenes
113
can cause gas gangrene
Clostridium perfringens
114
→produced by S. aureus and accelerates the
conversion of fibrinogen to a fibrin clot
Coagulase
115
Kinases
Streptokinase
Staphylokinase
116
→ destroy IgA antibodies found on secretions
Immunoglobulin A protease (IgA protease)
117
→ destroy neutrophilic leukocytes and macrophages
Leukocidin
118
→composed of two subunits: nontoxic (binds the toxin to the host cells) and toxic
→produced by both gram-negative and gram-positive bacteria
Exotoxins
119
→secreted by the organism into the extracellular environment, or they are released on lysis of the organism
→mediate direct spread of the microorganisms through the matrix of connective tissues and can cause cell and tissue damage
Exotoxins
120
→encoded by phages, plasmids, or transposons
Toxic Gene
121
→good antigens and induce the production of antibodies called
ANTITOXINS
122
When treated with formaldehyde (or acid or heat), the exotoxin polypeptides are converted into _____________, which are used in protective vaccines
TOXOIDS
123
Examples of EXOTOXINS
✓Diphtheria toxin
✓Tetanospamin
✓Botulism toxin
✓Heat labile enterotoxin by E. coli, Vibrio, Bacillus
✓Verotoxin
✓Erythrogenic toxin
✓Three toxins of B. anthracis (EF, PA, LF)
✓TSST-1
124
3 principal types on the basis of Exotoxin structure and function:
1. A-B Toxin
2. Membrane-Disrupting Toxins
3. Superantigens
125
→composed of the LPS portion of the outer membrane
on the cell wall of gram-negative bacteria
→do not have enzyme activity
→secreted in only very small amounts
→do not have specificity in their activity on host cells
ENDOTOXINS
126
→not very potent
→not destroyed by heating
→less antigenic and induce antibody production in a poor manner
→no toxoid have been produced from enough
endotoxin
ENDOTOXINS
127
Effects of Endotoxin
✓Stimulates the fever centers in the hypothalamus (1 hour after exposure)
✓Hypotension (30 minutes after exposure)→Shock
✓Initiates coagulation→DIC
✓Severe neutropenia
✓Activates macrophages, activates complement, and has an adjuvant effect with protein antigens
✓stimulates interferon production and causes changes in carbohydrates, lipids, iron, and sensitivity to epinephrine
128
→ test to detect endotoxins in drugs, medical devices, and body fluid
Limulus Lysate Test
129
Limulus Lysate Test
Reagent used:
Limulus polyphemus (horse shoe crab)
130
Principle of the Limulus Lysate test:
in the presence of endotoxin, the horse shoe crab will release amoebocytes which results to positive result of clumping
131
Positive Result of Limulus Lysate Test:
Clumping (there is endotoxin in the body fluid or bacterial instrument)
