Chapter 25 microbial infection and pathogenesis

studied byStudied by 2 people
5.0(1)
Get a hint
Hint

infection

1 / 33

flashcard set

Earn XP

Description and Tags

34 Terms

1

infection

a microbe is established and growing in a host, can be harmful or not to host. (infection to microbiome)

New cards
2

pathogens

Organisms that cause disease, or tissue damage in a host

New cards
3

Pathogenicity

the ability of an organism to cause disease

New cards
4

microbial adherence

adherence of pathogens to tissue via receptor molecules on the cell surface

New cards
5

bacterial capsules

forms a thick coating outside the plasma membrane and cell wall and serves two important functions in bacterial pathogenicity.

New cards
6

adherence structures:

Fimbriae, Pili, and Flagella

New cards
7

Fimbriae, Pili, and Flagella

bacterial cell surface protein structures that function in attachment.

New cards
8

Growth of the Microbial Community

example: Human Dental Caries (tooth decay)

New cards
9

Dental caries, or cavities, are an oral microbial disease.

Streptococcus sobrinus and Streptococcus mutans and other bacteria attach and reproduce and form a biofilm (plaque).

New cards
10

Invasiveness

ability of a pathogen to grow in host tissue at densities that inhibit host function

New cards
11

Bacteremia

the presence of bacteria in the bloodstream

New cards
12

Septicemia

bloodborne systemic infection, may lead to massive inflammation, septic shock and death (lethal in a quarter to half of all cases).

New cards
13

Infection

any situation in which a microorganism (not a member of the local flora) is established and growing in a host

New cards
14

Virulence

the relative ability of a pathogen to cause disease

New cards
15

Attenuation

the decrease or loss of virulence

New cards
16

Attenuated strains

of various pathogens are valuable to clinical medicine because they are often used for the production of viral vaccines, e.g. measles, mumps, polio, rubella.

New cards
17

pathogenicity islands

Several genes that direct invasion are clustered together on the chromosome

New cards
18

SPI1 and SPI2

•Salmonella pathogenicity islands contains genes that promote a more systemic disease. Salmonella also contains antibiotic antibiotic resistance plasmids (R plasmids).

New cards
19

Compromised Host

•(susceptible to infection)

•The pathogen-host interaction is dependent upon both the host and the pathogen.

•Certain medical procedures (e.g., surgery) or underlying conditions predispose individuals to  develop diseases.

New cards
20

Nosocomial infections (Hospital-acquired)

•affect nearly 2 million people each year.

•Infections with viruses, such as HIV, weaken the
immune system.

New cards
21

Opportunistic infections

are those caused by organisms that do not cause disease in healthy hosts

New cards
22

Invasiveness

•requires a pathogen break down host tissues. This is often done with enzymes that attack host cells.

New cards
23

Hyaluronidase

breaks down host tissues

New cards
24

Coagulase and streptokinase

manipulate clotting.  Coagulase forms clots, while streptokinase breaks them down.

New cards
25

Exotoxins

•proteins released from the pathogen cell as it grows and can cause damage at distant sites

•three categories

•AB toxins

•cytolytic toxins

•Superantigen toxins

New cards
26

Diphtheria Exotoxin

•Blockage of Protein Synthesis

•Can cause a thick covering in the back of the throat. It can lead to difficulty breathing, heart failure, paralysis, and even death

New cards
27

AB toxin

•that is made up of an Active (A) domain and a binding (B) domain

•The A domain adds an ADP-ribosyl group to elongation factor thermos unstable (EF-2), which prevents its function in translation.

New cards
28

Enterotoxins

•exotoxins whose activity affects the small intestine

•typically cause massive secretion of fluid into the intestinal lumen, resulting in vomiting and diarrhea

•example: cholera toxin

New cards
29

•Cytolytic Exotoxins (Cytotoxins)

•Soluble proteins that work by degrading cytoplasmic membrane integrity, causing cell lysis and death

New cards
30

hemolysins

Toxins that lyse red blood cells are called

New cards
31

Staphylococcal a-toxin

kills nucleated cells and lyses erythrocytes.

New cards
32

•Superantigens (SAG’s)

•cause an overstimulation of the immune system (usually of T cells leading to a “cytokine storm”)

•can lead to shock and death

•generally due to a localized infection, but with systemic effects

Mainly Gram +ve bacteria example: . S aureus and S pyogenes

New cards
33

lipopolysaccharide (LPS)

•portion of the cell envelope of certain gram-negative Bacteria, which is a toxin when solubilized

•LPS is a stimulator of the immune system

•Generally, less toxic than exotoxins and released when bacterial cell dies

New cards
34

•Limulus amoebocyte lysate (LAL)

•Presence of endotoxin can be detected by the Limulus amoebocyte lysate (LAL) assay.

New cards

Explore top notes

note Note
studied byStudied by 19 people
... ago
4.0(1)
note Note
studied byStudied by 168 people
... ago
5.0(2)
note Note
studied byStudied by 33 people
... ago
4.5(4)
note Note
studied byStudied by 6 people
... ago
5.0(1)
note Note
studied byStudied by 4 people
... ago
5.0(1)
note Note
studied byStudied by 12 people
... ago
5.0(1)
note Note
studied byStudied by 69 people
... ago
5.0(1)
note Note
studied byStudied by 624 people
... ago
4.0(5)

Explore top flashcards

flashcards Flashcard (36)
studied byStudied by 2 people
... ago
5.0(1)
flashcards Flashcard (35)
studied byStudied by 11 people
... ago
5.0(1)
flashcards Flashcard (310)
studied byStudied by 20 people
... ago
5.0(1)
flashcards Flashcard (53)
studied byStudied by 2 people
... ago
5.0(1)
flashcards Flashcard (22)
studied byStudied by 4 people
... ago
5.0(1)
flashcards Flashcard (79)
studied byStudied by 27 people
... ago
5.0(1)
flashcards Flashcard (47)
studied byStudied by 37 people
... ago
5.0(1)
flashcards Flashcard (46)
studied byStudied by 15 people
... ago
5.0(1)
robot