Host-Pathogen Interaction

0 min read

Posted on

May 24th, 2023

question

Infection based on...

answer

hosts immune system

microbial factors inherent to the invading organism

question

Fetus is...

answer

sterile until birth

question

Symbiosis

answer

two organisms living together

question

Mutalism

answer

both benefit

question

Commensalism

answer

microorganism benefits while host is not harmed

question

Parasitism

answer

microorganism benefits while host is harmed

question

transient flora

answer

microbes temporarily colonizing a host

question

carrier state

answer

condition of hosts capable of transmitting the infection

acute: Group b Strep

chronic: long term - MRSA

question

Composition of usual microbiota is influenced by

answer

specific nutrional and environmental factors

* organisms must resist the antibacterial effects of: bile, lysozyme, fatty acids

question

Normal biota of Mouth

answer

bacterial plaque

Low oxid/reduct potential - anaerobes grow

tooth surface - acid by microbes causes tooth decay

question

Normal Biota of the Skin

answer

*superficial organisms - skin surface and hair follicles

sweat glands - sweat substances met by bacteria

question

upper respiratory tract

answer

mouth nasopharynx, oropharynx, larynx

question

Lower respiratory tract

answer

trachea, bronchi, pulmonary parenchyma

question

Normal Biota of the GI Tract

answer

usually sterile except endospores, parasitic cysts and H. pylori - ulcers

*anitbiotics ul;ter the usual flora

question

Sterile sites of the genitourinary tract

answer

kidneys, bladder, fallopian tubes

question

Nonsterile sites of the genitourinary tract

answer

distal urethra

vagina

question

When good biota turns bad...

answer

opportunistic infections, trauma, immunosuppression, chronic illness

question

true pathogens

answer

capable of causing disease in healthy persons with normal immune defenses - Y. pestis and B. anthracis

question

Virulence factors

answer

traits that determine pathogenicity and virulence

* capsules and toxins

question

Phagocytes

answer

major role in clearing bacterial infection

question

Capsules

answer

inhibit engulfment

mask cell structures recognized by receptors on the phagocyte cell surface

question

Protein A

answer

Binds Fc region of IgG. Prevents opsonization and phagocytosis and turns antibody around. Expressed by S. aureus.

question

Leukocidins

answer

Panton-Valentine

lethal to leukocytes

question

Inhibits chemotaxis

answer

Coagulase - movement of WBC to tissue is affected

question

adhesions

answer

microbial surface structures that mediate attachment

*host cells must have receptors for the adhesions

* spike protein - COVID

question

Adhesive structures on bacteria

answer

main adhesion in bacteria

surface polysaccharides

question

Secretory Antibody

answer

IgA proteases

antigenic variation

* prevent organism from being killed intracellularly *

question

Lactoferrin

answer

binds free iron

use this for iron

* prevent organism from being killed intracellularly *

question

Lysosomes

answer

prevent fusion

escape phagosome

* prevent organism from being killed intracellularly *

question

Exotoxins

answer

secreted by bacteria

binding subunit and toxic subunit

question

binding subunit of exotoxins

answer

allows toxin to enter cell

question

toxic subunit of exotoxins

answer

disrupts or destroys cellular function

question

Endotoxins

answer

lipopolysaccharide portion of the outer membrane of gram-negative bacteria

question

Lipid A (endotoxin)

answer

stimulates release of cytokines that aid in mounting an immune response - fever, hypotension, septic shock, coag, neutropenia

question

Steps for phagocytosis

answer

attachment, ingestion, killing

question

humoral immune response

answer

B cells aided by helper T cells, undergo multiple divisions to become plasma cells

question

plasma cells

answer

produce antibodies

question

Immunoglobulin G

answer

monomer, most abundant, crosses placenta

question

Immunoglobulin M

answer

pentamer, first antibody produced, able to attach more

question

IgA

answer

dimer, secreted at mucous membranes

question

IgE

answer

receptor bound, very low serum concentration, helps clear parasites and allergies

question

IgD

answer

surface of B cells

question

Primary exposure

answer

IgM first then IgG follows

question

Secondary exposure

answer

IgM constant, IgG skyrockets

question

Cytotoxic T cells

answer

kill infected cells

question

T helper cells

answer

signal activation of macrohpages

question

Microbe mechanisms

answer

induce immune tolerance

immune suppression

antientic variation

intracellualr hiding

1 of 47

question

Infection based on...

answer

hosts immune system

microbial factors inherent to the invading organism

question

Fetus is...

answer

sterile until birth

question

Symbiosis

answer

two organisms living together

question

Mutalism

answer

both benefit

question

Commensalism

answer

microorganism benefits while host is not harmed

question

Parasitism

answer

microorganism benefits while host is harmed

question

transient flora

answer

microbes temporarily colonizing a host

question

carrier state

answer

condition of hosts capable of transmitting the infection

acute: Group b Strep

chronic: long term - MRSA

question

Composition of usual microbiota is influenced by

answer

specific nutrional and environmental factors

* organisms must resist the antibacterial effects of: bile, lysozyme, fatty acids

question

Normal biota of Mouth

answer

bacterial plaque

Low oxid/reduct potential - anaerobes grow

tooth surface - acid by microbes causes tooth decay

question

Normal Biota of the Skin

answer

*superficial organisms - skin surface and hair follicles

sweat glands - sweat substances met by bacteria

question

upper respiratory tract

answer

mouth nasopharynx, oropharynx, larynx

question

Lower respiratory tract

answer

trachea, bronchi, pulmonary parenchyma

question

Normal Biota of the GI Tract

answer

usually sterile except endospores, parasitic cysts and H. pylori - ulcers

*anitbiotics ul;ter the usual flora

question

Sterile sites of the genitourinary tract

answer

kidneys, bladder, fallopian tubes

question

Nonsterile sites of the genitourinary tract

answer

distal urethra

vagina

question

When good biota turns bad...

answer

opportunistic infections, trauma, immunosuppression, chronic illness

question

true pathogens

answer

capable of causing disease in healthy persons with normal immune defenses - Y. pestis and B. anthracis

question

Virulence factors

answer

traits that determine pathogenicity and virulence

* capsules and toxins

question

Phagocytes

answer

major role in clearing bacterial infection

question

Capsules

answer

inhibit engulfment

mask cell structures recognized by receptors on the phagocyte cell surface

question

Protein A

answer

Binds Fc region of IgG. Prevents opsonization and phagocytosis and turns antibody around. Expressed by S. aureus.

question

Leukocidins

answer

Panton-Valentine

lethal to leukocytes

question

Inhibits chemotaxis

answer

Coagulase - movement of WBC to tissue is affected

question

adhesions

answer

microbial surface structures that mediate attachment

*host cells must have receptors for the adhesions

* spike protein - COVID

question

Adhesive structures on bacteria

answer

main adhesion in bacteria

surface polysaccharides

question

Secretory Antibody

answer

IgA proteases

antigenic variation

* prevent organism from being killed intracellularly *

question

Lactoferrin

answer

binds free iron

use this for iron

* prevent organism from being killed intracellularly *

question

Lysosomes

answer

prevent fusion

escape phagosome

* prevent organism from being killed intracellularly *

question

Exotoxins

answer

secreted by bacteria

binding subunit and toxic subunit

question

binding subunit of exotoxins

answer

allows toxin to enter cell

question

toxic subunit of exotoxins

answer

disrupts or destroys cellular function

question

Endotoxins

answer

lipopolysaccharide portion of the outer membrane of gram-negative bacteria

question

Lipid A (endotoxin)

answer

stimulates release of cytokines that aid in mounting an immune response - fever, hypotension, septic shock, coag, neutropenia

question

Steps for phagocytosis

answer

attachment, ingestion, killing

question

humoral immune response

answer

B cells aided by helper T cells, undergo multiple divisions to become plasma cells

question

plasma cells

answer

produce antibodies

question

Immunoglobulin G

answer

monomer, most abundant, crosses placenta

question

Immunoglobulin M

answer

pentamer, first antibody produced, able to attach more

question

IgA

answer

dimer, secreted at mucous membranes

question

IgE

answer

receptor bound, very low serum concentration, helps clear parasites and allergies

question

IgD

answer

surface of B cells

question

Primary exposure

answer

IgM first then IgG follows

question

Secondary exposure

answer

IgM constant, IgG skyrockets

question

Cytotoxic T cells

answer

kill infected cells

question

T helper cells

answer

signal activation of macrohpages

question

Microbe mechanisms

answer

induce immune tolerance

immune suppression

antientic variation

intracellualr hiding

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