Pathogenesis Of Microbes

Question 1

Infection:

____________ of an infectious agent within the body.

Answer 1

Multiplication

Question 2

Multiplication of the bacteria that are part of normal flora of gastrointestinal tract, skin, etc, is generally considered an infection.

T/F

Answer 2

F

Not

Question 3

On the other hand, multiplication of pathogenic bacteria (e.g. Salmonella species), even if the person is _______, is deemed an infection.

T/F

Answer 3

asymptomatic

T

Question 4

Pathogenicity:
The ability of an infectious agent to __________

Answer 4

cause disease.

Question 5

Virulence:
The ______ of an agent to _______

Answer 5

quantitative ability

cause disease.

Question 6

Virulent agents cause disease when introduced into the host in (small or large ?) numbers.

Answer 6

Small

Question 7

Virulence involves _________ and _________

Answer 7

invasiveness and toxigenicity.

Question 8

Toxigenicity:
The ability of a microorganism to ______________

Answer 8

produce a toxin that
contributes to the development of disease.

Question 9

Invasion:
The process whereby bacteria, parasites, fungi and viruses ———————

Answer 9

enter the host cells or tissues and spread in the body.

Question 10

Pathogen is A microorganism capable of causing disease.

T/F

Answer 10

T

Question 11

Non-pathogen is A microorganism that does not cause disease. It may be part of the normal flora.

T/F

Answer 11

T

Question 12

Opportunistic pathogen:
An agent capable of causing disease only when _______________

An agent capable of causing disease only when spread from the site with __________________ to the _________

Answer 12

the host ́s resistance is impaired (e.g. the patient is immunocompromised).

normal bacterial microflora

sterile tissue or organ.

Question 13

The pathogenesis of bacterial infection includes the _____ of the infectious process and the mechanisms leading to the development of signs and symptoms of bacterial disease.
The outcome of the interaction between bacteria and host is determined by characteristics that favour establishment of the bacteria within the host and their ability to damage the host as they are opposed by host defense mechanisms.

Answer 13

initiation

Question 14

Oubreak - ______
Epidemic - _______
Pandemic – _________

Answer 14

local

regional/national

widespread (international)

Question 15

Most bacteria do not produce disease but ____________________ that ensures the survival, growth, and propagation of both the bacteria and the host.

Answer 15

achieve a balance with the host

Question 16

Most bacteria produce disease

T/F

Answer 16

F

Question 17

Sometimes bacteria that are clearly pathogens (e.g. Salmonella typhi) are present, but infection remains ____ or ______ and the host is a “ ______ “ of the bacteria.

Answer 17

latent

subclinical

carrier

Question 18

In 1884, Robert Koch proposed a series of postulates in his treatise on ______ as _______

Answer 18

Mycobacterium tuberculosis and tuberculosis.

Question 19

Koch ́s postulates are summarized as follows:

The microorganism should be _______of the disease in question, and its distribution in the body should be in accordancce with the _______ observed.

The microorganism should be grown in ______________ for several ______.

When such a pure culture is __________, the ________ must result.

The microorganism must again be ___________

Answer 19

found in all cases ; lesions

pure culture in vitro;23

inoculated into susceptible animal species; typical disease

isolated from the lesions of such experimentally produced disease.

Question 20

Koch ́s postulates remain a mainstay of microbiology.

T/F

Answer 20

T

Question 21

However, since the late 19th century, many microorganisms that do not meet the criteria of the postulates have been shown to cause disease. For example, Treponema pallidum (____) and Mycobacerium leprae (____) cannot be ______, but there are _________

Answer 21

syphilis; leprosy

grown in vitro

animal models of infection with these agents.

Question 22

In another example, Neisseria gonorrhoeae (gonorrhea), there is no __________ even though the bacteria can readily be ________

Answer 22

animal model of infection

cultivated in vitro.

Question 23

The __________ should be considered when an organism is being investigated as the possible cause of a disease.

Answer 23

host ́s immune responses

Question 24

Analysis of infection and disease through the application of principles such as Koch ́s postulates leads to classification of bacteria as ________ or _________

Answer 24

pathogenic or non- pathogenic.

Question 25

Examples of pathogenic bacterias include ______ (tuberculosis) and ___________ (plague).

Answer 25

Mycobacterium tuberculosis Yersinia pestis

Question 26

Other species are commonly part of the normal flora of humans (and animals) but can also frequently cause disease. For example, Escherichia coli is part of the gastrointestinal flora of normal humans, but it is also a comon cause of __________ infection, _______, and other diseases.

Answer 26

urinary tract Traveller’s diarrhea

Question 27

The infectious process Infection indicates _______ of microorganisms. Prior to that, bacteria (in case of bacterial infection) must ______ and ______ within the host. The most frequent portals of entry are the _______,_______, and ________ tracts. Abnormal areas of ________ and ———- (e.g. cuts, burns) are also frequent sites of entry.

Answer 27

multiplication enter and establish themselves respiratory (mouth and nose), gastrointestinal, and urogenital mucous membranes and skin

Question 28

Nosocomial- originating in the ______

Answer 28

Hospital

Question 29

Gist defenses Gut : ______,______ respiratory tract: ______,_______,_______ urogenital tract; _______

Answer 29

peristalsis , defecation ciliary action ,coughing , sneezing urination

Question 30

Connective tissue destrction Helps bacterial dissemination T/F

Answer 30

T

Question 31

Connective tissue destrction by : ________ ________

Answer 31

collagenase hyaluronidase

Question 32

Extracellular pathogens are resistant to extra-cellular killing T/F

Answer 32

T

Question 33

Extracellular pathogens are killed on _________

Answer 33

phagocytosis

Question 34

Extracellular pathogens resist killing by avoiding ________

Answer 34

internalization

Question 35

Toxins produced by bacteria are generally classified into two groups: ______ ________

Answer 35

exotoxins endotoxins

Question 36

Diphtheria toxin (toxin of Corynebacterium diphtheriae) Corynebacterium diphtheriae strains that carry a _______ with the structural gene for the toxin are toxigenic and produce diphtheria toxin. This native toxin is enzymatically degraded into two fragments: ____ and ____, linked together by a ____ bound. Both fragments are necessary for toxin activity.

Answer 36

temperate bacteriophage A and B disulfide

Question 37

Tetanospasmin (toxin of Clostridium tetani) Clostridium tetani is an (aerobic or anaerobic?) gram-______ —— that is widespread in the environment. Clostridium tetani contaminates _____, and the spores germinate in the anaerobic environment of the devitalized tissue.

Answer 37

Anaerobic; positive ; rod wounds

Question 38

The vegetative forms of Clostridium tetani produce toxin ______. The released toxin has two peptides linked by disulfide bounds. Toxin reaches the central nervous system by ____ transport along _____ and through the _____ circulation. The toxin acts by blocking release of (excitatory or inhibitory?) mediator in motor neuron synapses. The result is initially _____ then _____, _____.

Answer 38

tetanospasmin retrograde axons; systemic inhibitory; localized; generalized muscle spasms

Question 39

Extremely small amount of toxin tetanospasmin can be lethal for humans. T/F

Answer 39

T

Question 40

Botulotoxin (toxin of Clostridium botulinum) An exceedingly potent toxin is produced by Clostridium botulinum strains. It is heat-(labile or stable?) and is destroyed by ________. There are _____ disctinct serological types of toxin. Types ___ are most commonly associated wih human disease. Toxin is absorbed from the ______ and carried to motor nerves, where it blocks the ___________ at synapses and neuromuscular junctions. Muscle ______ does not occur, and ______ results.

Answer 40

Labile; sufficient heating eight; A, B and E gut; release of acetylcholine contraction; paralysis

Question 41

the most potent toxin known is ??

Answer 41

Botulotoxin

Question 42

Toxins of Clostridium perfringens Spores of Clostridium perfringens are introduced into the wounds by contamination with ________. In the presence of ______ tissue (an anaerobic environment), spores germinate and vegetative cells produce several different toxins. Many of these are _______ and _____ and favour the spread of ______, eg: alpha toxin is a _____ that damages ________ ______ toxin also has a necrotizing affect and other

Answer 42

soil or faeces necrotic necrotizing and hemolytic gangrene lecithinase; cell membranes theta

Question 43

Streptococcal erythrogenic toxin( aka streptococcal ___________ toxin) Some strains of hemolytic lysogenic streptococci produce a toxin that results in a _______________________________ rash, as in _______. Production of erythrogenic toxin is under the genetic control of ________. If the phage is lost, the streptococi cannot produce toxin.

Answer 43

Pyrogenic punctate maculopapular erythematous scarlet fever temperate bacteriophage

Question 44

Toxic shock syndrom toxin - 1 (TSST-1) Some _____________ strains growing on mucous membranes (e.g. on the vagina in association with menstruation), or in wounds, elaborate TSST-1. Although the toxin has been associated with toxic shock syndrome, the mechanism of action in unknown. The illness is characterized by ____,___, and a diffuse _____ that later desquamates, multiple other organs systems are involved as well.

Answer 44

Staphylococcus aureus shock, high Fever red rash

Question 45

Exotoxins are associated with diarrheal diseases T/F

Answer 45

T

Question 46

Cholera toxin and E. coli labile toxin Causes ______ of regulator That leads to _______ activation leading to increase in _____ There’s _______ that leads to the diarrhea

Answer 46

ADP-ribosylation adenylate cyclase cyclic AMP active ion and water secretion

Question 47

Shiga toxin -_______ Shiga-like toxin – enterohemorrhagic E. coli • lyses _____- in ribosome leading to death of __________ • poor ________ that sums up into diarrhea

Answer 47

shigellosis 28S rRNA epithelial cells water absorption

Question 48

Endotoxins of gram-negative bacteria The endotoxins of gram-negative bacteria are derived from bacterial _______ and are often liberated when the _________. The substances are heat-(labile or stable?) and can be extracted (e.g. with ________)

Answer 48

cell walls; bacteria lyse Stable; phenol-water

Question 49

Pathophysiological effects of endotoxins are similar regardless of their bacterial origin T/F

Answer 49

T

Question 50

Coagulase: Staphylococccus aureus produce coagulase, which works in conjuction with serum factors to _______. Coagulase contributes to the formation of ______ around staphylococcal lesions, which helps them persist in tissues.

Answer 50

coagulate plasma fibrin walls

Question 51

Hyaluronidases: Enzymes that _________, a constituent of the ground substance of connective tissue. They are produced by many bacteria (e.g. staphylococci, streptococci and anaerobes) and aid in their spread through tissues.

Answer 51

hydrolyze hyaluronic acid

Question 52

Streptokinase: many hemolytic streptococci produce streptokinase (________), substance that activates a proteolytic enzyme of plasma. This enzyme, is then able to ____________ and probably aids in the spread of streptococci through tissues.

Answer 52

fibrinolysin dissolve coagulated plasm

Question 53

Streptokinase is used in treatment of __________ to ________

Answer 53

acute myocardial infarction dissolve fibrin clots

Question 54

Hemolysins and leukocidins: Many bacteria produce substances that are ______ - they ___________(hemolysins) or _____________ (leukocidins).

Answer 54

cytolysins dissolve red blood cells ; kill tissue cells or leukocytes

Question 55

Streptolysin O, for example, is produced by group ___ streptococci and is lethal for ____ and hemolytic for red blood cells from many animals.

Answer 55

A mice

Question 56

_______ proteases help the following survive on external surfaces H.________ S.________ N._______ N. ______

Answer 56

IgA influenzae; pneumoniae; gonorrhoeae meningitidis

Question 57

Once bacteria enter the body of the host, they must ______.If they do not adhere, they would be _________ and other fluids that bathe the tissue surface.

Answer 57

adhere to cells of a tissue surface swept away by mucus

Question 58

Most common form of bio terrorism is ___?

Answer 58

By air