BSCI223 Final Exam

The bacteria must be present in every case of the disease. The bacteria must be isolated from the host with the disease and grown in pure culture. The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.

What are Koch's Postulates?

must be infectious, asymptomatic carriers, strain variation, viral diseases, disease based on site of infection, disease with multiple causes, diseases requiring multiple conditions, ethics

limitations of Koch's postulates?

Symbiosis

"To live together"

Mutualism

Both organisms benefit

Commensalism

One benefits and one is unaffected

Amensalism/anitbiosis

one is harmed and one is unaffected

parasitism

one is harmed and the other benefits

methanogens in rumen, human digestive tract bacteria, bacteria in termites, lychens (algae and fungi), leaf cutter ants and fungi

examples of mutualism?

Contamination

presence of microbes in or on the body

infection

when organisms evade a body's external defenses to grow and multiply (aka colonization)

distal

microbes increase as you more proximal or distal through the GI tract?

birth-1 year

when do we have increasing numbers of microbes?

yes

does composition of normal flora change throughout lifetime?

birth

when does colonization start?

prevention of disease, nutrition

advantages of microbiota for host

produce chemicals

how does normal microbiota stimulate immunity?

consume substrates and provide essential metabolites

how does normal microbiota help with nutrition?

predictable environment, nutrition source, protection from competition

advantages to microbe in normal microflora?

each other

symbionts co-evolve in response to...

obesity, allergy, type 1 diabetes

what can microflora influence?

cause them to latch onto something to be eaten

what can fungal or flatworm infections do when they cause "zombie ants"?

reduces fight or flight

what does toxoplasma do in mice?

spontaneous abortion and schizophrenia

what is toxoplasma associated with in humans?

pathogens

microorganisms that cause disease

microbiota in abnormal site of body, immune suppression, changes in normal flora, changes in relative abundance

how can pathogens be established?

opportunistic pathogens

members of normal microbiota that produce disease under certain circumstances

zoonotic pathogens

a disease-causing agent that is transmitted to humans from other animals

clostridium dificile, legionella pneumophila, pseudomonas aeruginosa, streptococcus pneumoniae

opportunistic pathogens?

borrelia burgdorferi, salmonella typhimurium, bacillus anthracis, rickettsia

zoonotic pathogens?

skin, mucous membranes, placenta

three main portals of entry?

parenteral route

not a true portal of entry, pathogen deposited directly into tissue (open wound or site of injection, insect bite)

respiratory tract

what is the most common site of entry for pathogens

pathogenicity

ability of a microorganism to cause disease

virulence

degree of pathogenicity

helps bacteria grow and replicate, may form biofilm

what does adhesion do for virulence?

pathogen

what are extracellular enzymes secreted by?

dissolve structural chemicals to help pathogen invade, infect, and avoid

what do extracellular enzymes do?

hyaluronidase and collagenase

extracellular enzymes that can break down junctions b/w epithelial cells

coagulase and kinase

extracellular enzymes that can protect from immune response by forming a clot

toxins

chemicals that cause harm to tissues or trigger host immune responses that cause damage

toxemia

toxins in the blood stream

endotoxins

toxins produced by dead gram negative cells releasing their lps layer

exotoxin

bacteria secreted from a living cell

capsule and antiphagocytic chemicals

what are the antiphagocytic factors?

gene expression changes

what happens when cells hit quorom of high cell density?

prevent fusion of lysosome and phagocytic vesicles

what do antiphagocytic chemicals do?

proteins and polysaccharides

what are biofilms made of?

streptococcus pneumoniae, haemophilus influenzae, respiratory syncytial virus, pneumocystis jiroveci

etiologic agents of pneumonia?

wash hands, vaccines, reduce indoor air pollution, breast feeding, nutrition

ways to prevent pneumonia?

capsule, phosphorylcholine, adhesins, pneumolysin, hyaluronidase

virulence factors of streptococcus pneumoniae?

sinus ear eye infections

what is s pneumoniae the etiologic agent for in addition to pneumonia?

lung, sinus, and middle ear

s pneumoniae is normal part of which flora?

pneumolysin

exotoxin produced by strep pneumoniae that lyses and inhibits immune cells

pneumococcal pneumonia

type of pneumonia caused by s pneumoniae that grows in alveoli and damages cells so those cells then get taken up by phagocytes, releases pyrogens

bacterimia

bacteria in blood stream through tissue damage, wounds, or gums

inhibits complement

what does pspa do?

release pneumolysin and cell wall products

what does autolysin do?

skin, mucus membranes, normal flora, inflammation, macrophages

what are the components of innate immunity?

inflammation

nonspecific response to tissue damage

redness, heat, swelling, pain

what is inflammation characterized by?

dilation and permeability of blood vessels, phagocytes migrate for tissue repair

why is inflammation important for adaptive/secondary immunity?

rubor

redness due to increased blood flow

calor

heat due to increased blood flow and pyrogens

tumor

swelling that is caused by accumulation of fluid in extra vascualr space and also somewhat by mass of inflammatory cells

dolor

pain due to stretching and distortion of tissues from edema and chemical mediators

cut, damaged cells release prostaglandins, leukotrienes, and histamine, vessels permeable and dilated, macrophages and neutrophils squeeze through vessel walls, antimicrobial chemicals and clotting proteins seep into tissue, blood clot forms, more phagocytes, pus forms, stem cells repair tissue

what is the process of inflammation?

toll-like

what type of receptors do phagocytes have?

antigens

what do phagocytes release?

LPS, flagellin, peptidoglycan, bacterial nucleotide sequences

what are some things toll-like receptors can detect?

chemotaxis, adherence, ingestion, fusion of vesicles, microbes killed by enzymes and other chemicals, elimination (exocytosis)

what are the stages of phagocytosis?

specificity, inducibility, clonality, unresponsiveness to self, memory

what are the five attributes of specific immunity?

large macromolecules

what makes the best antigens?

damaged tissues, invading microbes, antigens, macrophages, antibodies, serum

what are the components of pus?

tertiary

epitopes are what type of structure?

exogenous antigens

free-living bacteria that have antigens on surface

endogenous antigens

antigens made inside our cells that end up on cell surface (usually caused by virus)

autoantigens

normal antigens present on our cells

spleen, lymph nodes, mucosal associated lymph tissue

where are b cells usually found?

immunoglobulin

what is the b cell receptor?

two variable regions

what is antigen binding site created by?

vdj recombination

what type of recombination determines what a b-cell receptor will be?

activate complement and inflammation, neutralization, immobilization, opsonization, agglutination, precipitation, antibody dependent cellular cytotoxicity

what are the functions of antibodies?

neutralization

inactivate toxins to prevent interaction with cells

immobilization

prevent bacteria from adhering or swimming to prevent maintenance and spread of infection

removes toxins and helps with phagocytosis

what does agglutination and precipitation do?

opsonization

facilitates removal by phagocytes

pathogen associated molecular patterns

what do toll-like receptors recognize?

glycoproteins

what are mhc antigens?

antigen binding groove

where do antigens bind to mhc?

mhc 1

mhc that is present on all cells excpet rbcs bc no nucleus

mhc 2

mhc that is only present on antigen-presenting cells

endogenous

what type of antigens does mhc 1 present?

exogenous

what type of antigens does mhc 2 present?

lymph and blood

where are t cells usually found?

lymph nodes, spleen, peyer's patches

where do t cells migrate to?

no

do t cell receptors recognize epitopes directly?

cd4

what surface protein do helper t cells have?

cd8

what surface protein do cytotoxic t cells have?

2

what mhc do helper t cells recognize?

1

what mhc do cytotoxic t cells recognize?