No living cells, spores, or viruses

reducing microbials numbers to levels safe for the public

-dishwasher

Antiseptics

kill or inhibit infection causing organisms from living tissues

-what you put on a wound

kill a certain organism

-fungicide, viricide, bactericide

• Heating-doesnt kill spores
• Autoclave-kills all cells and spores
• Pasteruization-doesnt kill spores
• Baking-kills all cells and spores
• Filtration-just removes
• UV-damages DNA 

• Population size
• Population composition
• Temperature
• Concentration of anti-microbial agent
• Length of exposure
• Local environment

• Bind to ribosomes, stop translation
• Stop cell wall synthesis
• Disrupt membranes
• Stop nucleic acid synthesis
• Inhibit metabolic pathways

Bacterial Mechanisms of Antibiotic Resistance

• Prevent drug entrance
• Efflux pumps-nonspecific 
• Drug inactivation-making an enzyme that deactivates the drug coming in
• Target modification-changes to RNA sequences in the ribosomes, alterations in tetrapeptide, alternative metabolic pathways

• Spontaneous mutations
• Horizontal gene transfer-sharing genes, conjugation

1 benefits, the other is neither harmed nor benefits

-bacteria on our skin, gut

Both organisms benefit

-Lichens

-Deep sea H2S vents

-Ruminants

-Termites

-Green flat worms

Any disease causing pathogen, 1 benefits and 1 is harmed; least common type of symbiosis

-Photosynthetic sea slugs

Organisms that routinely reside on the body's surface

*not in lungs!

How are normal flora protective?

1. compete for attachment with pathogenic bacteria
2. produce antimicrobial substances that fight off and help destro pathogenic bacteria
3. stimulate the immune system, keeps immune system slightly activated

Infectious disease

Pathogens

Virulence

Three factors affecting parasitiism

1. # of organisms inoculated
2. virulence of organism
3. hosts degree of resistance 

Symptoms

subjective (cant see it)

nausea, pain, loss of apetite 

Signs

something you can observe

rash, fever, swelling

• neurotoxins- affect nervous system
• enterotoxins- affect GI tract
• cytoxins-affect cellular function
• superantigens** unique! over stimulate the immune system, become leaky, 20% of T cells activated

Endotoxins

LPS

only gram negative

sluffed off when gram negative dies

weak immune response

no vaccine made for it

multiorgan failure

Innate Immunity Barriers

• Physical Barriers: skin, GI tract, mucous, respiratory tract, genitourinary tract, eye
• Chemical Barriers: antimicrobial peptides**
• Molecular defenses: complement, type I interferons
• Cellular Defenses
• Inflammation
• Fever

Antimicrobial peptides

• Defensins: found in skin and punch holes in bacteria membranes
• Histanin: has antifungal activity, targets mitochondrial membrane inside of fungus-very specific
• Lactoferrin and Transferrin-bind to iron so microbes cant get it
• baceriocin: (bacteria make this one), produced by normal flora, defense against other bacteria

• Opsonization:components bind to viruses and bacteria to be better taken up by macrophage
• Direct lysis of bacteria-forms pore causing it to lyse
• Inflammation 

Cytokines

protein communication molecules

IL-2, IL-4, Type I interferons

Granular cells

Toxic molecules

• Mast cells-release histamine
• Neutrophils-first reactors, phagocytosis
• Basophils-release histamine
• Eosinophils-first parasities, allergies

Agranular Cells

Not toxic

• T cells
• B cells
• Macrophages-present antigen to T cells, phagocytosis
• Dendritic cells-present antigen to T cells, phagocytosis
• Natural Killer cells-kill infected cells and tumor cells

• **Cause inflammation
• Activation of vascular endothelium
• Increase vascular permeabillity
• Increase vasodilation (blood slows down)
• Sticky adhesion goes up

4 Major Benefits of Fever

1. Slows the growth rate of microbes
2. Inactivates some bacterial toxins
3. Increases immune system activity
4. Forces a person to fill ill and allows for rest for energy to be restored

Secondary Response

Memory Respsonse

response is more robust and faster

Antigen

Epitopes

proteins have epitopes, or short amino acid sequences that are recognized by antibodies and T Cells

*for each epitope there is a B cell

IgM

IgD

IgA

Whole organism vaccines

• Live attenuated-live passaged in culture until no longer pathogenic but still immunogenic
• Inactivated or killed-killed with heat or chemicals, but still immunogenic

Subunit vaccines

• Toxoids-exotoxin inactivated, "fake toxin"
• Polysaccharide capsules- S. pneumoniae
• Viral glycoproteins
• Recombinant or native proteins

DNA vaccines

inject with plasmids that express antigens in host tissues

**need to add adjuvants because plasmids get lost in our big human body so adjuvants trigger danger signals better at ativated T cells, adjuvants can also be toxic

Recombinant vector vaccines

*use of viruses or bacteria to deliver genes of interest 

Dr. Taylor tried this with TB

Ability to grow in or on host

• must have correct pH
• must have correct temp
• correct O2 content
• hemolysins-lyse, RBC, anemia

Coagulase

forms clot around microbes

avoid host immune system

Protein A

Hiding within a host cell

avoiding host immune system

survive with phagocyte 

-some bacteria are able to escape the phagosome before phagolysomal fusion

-some able to prevent phagosome and lysosome fusion: TB do this

Collagenase

Leishmaniasis

Intoxications

Mucocilliary escalator

Extravasation

neutrophils squeeze between cellular junctions 

-diapedesis

-inflammation 

Pyrogens

Substances that cause fever

Exogenous pyrogens: LPS, Exotoxins

Endogenous pyrogens: macrophages release IL-1