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bio exam 3

Terms in this set (233)

symbiosis
living together
mutualism
both parties benefit
co evolution: adapt to depend each other
example of mutualism
E. coli
commensalism
microbe benefits, host unaffected
coevolution
adapt to depend each other
tolerance
immune system does not fight non-destructive organisms
probiotic
live microbes applied to or ingested into the body, intended to exert a beneficial effect
example of commensalism
diptheroids
parasitism
pathogen always harms the host
examples of parasitism
Vibrio cholera
shigella
salmonella
virulence
measure of the amount of harm damage inflicted by the pathogen
normal microbiota
permanently colonize the host and do not cause disease under normal conditions
opportunistic infection
Infections that occur when the body's defenses are weakened
tools for invasion
-Adhesins (adhesion via fimbriae)
-IgA protease (destruction IgA on mucus)
-capsules: protect phagocytosis
-C5a peptidase: destruction of complement protein
-M protein: (prevent opsonization in strept)
-Intracellular infection (inhibit phagolysosome function)
-Antigenic variation (org changes appearance)
ID50
the number of microorganisms required to produce a demonstrable infection in 50% of the test host population
LD50
the lethal does for 50% of the inoculated hosts within a given period
exotoxins
secreted outside cell
mostly by G +
by living cells
most are proteins
have specific effects
low LD50 (ng)
example of exotoxins
botulism, tetanus, diptheria
endotoxins
part of cell wall
all by G-
form dying cells
all are lipids (LPS)
have systemic effects
high LD50 (mg)
examples of endotoxins
UTI
typhoid
meningococcal meningitis
AB exotoxins
composed of two subunits
A subunit - responsible for toxic effect
B subunit - binds to specific target cell
AB exotoxin example
diphtheria toxin
membrane disrupting toxins
lyse host cells by disrupting plasma membranes
example of membrane disrupting toxin
S. aureus
C. perfringens
superantigen
antigen which yields an exaggerated response
example of super antigen
toxic shock syndrome
Kotch's Postulates
strict chain of evident that links a specific organism with a specific disease
1. pathogen must be present in all with disease
2. pathogen must be isolated and grown in pure culture
3. cultured pathogen must cause the same disease in inoculated test animal
4. same pathogen must be isolated from inoculated animal
why are kochs postulates difficult to apply to some organisms?
some can't be isolated and they have to be grown in vivo
etiology
cause of disease
epidemiology
Branch of medical science concerned with the incidence, distribution, and control of diseases that affect large numbers of people.
infectious reservoirs
natural habitat, harbors and allow the spread of pathogen
human
animals
non-living
human reservoirs
carriers may have inapparent infections or latent diseases
cold flu strep
animal reservoirs
contact transfers to humans (zoonoses)
rabies, lyme, toxo
non-living reservoirs
environmental microbes in soil or H20
botulism, tetanus
main portals of exit
doorway out of the host
respiratory
gastrointestinal
wounds
blood
urogenital
respiratory exit
in coughing, sneezing TB
gastrointestinal exit
feces or vomit
Cholera
wound exit
skin, pus, tissue
mRSA
blood exit
venipuncture, surgery, transfusions
Hep B
Urogenital exit
semen or vagina secretion
STD
portals of entry
doorway into new host
mucous membranes
parenteral rout
unbroken skin
mucous membranes entry
most common entry
all openings of body lined with mucous membranes
mouth, nose, eyes, anus, vagina, urethra
parenteral route
though break in skin
unbroken skin
rare entry thru pore or follicle
contact transmission
direct, indirect, droplet
direct contract transmission
requires physical connection
example of direct contract transmission
mono STD
indirect contract transmission
intermediate objects (fomite) like glasses, bedrails, toilets, doorknobs
example of indirect contract transmission
mRSA
Droplets contact transmission
body secretion (<1 meter) from short distance (<1 meter)
example of Droplets contact transmission
cold flu
vehicle transmission
food/ water: via contaminated water or food
blood: via contaminated blood or body fluids
airborne: carried on dry air currents > 1 meter
example of diseases through contaminate food/water
salmonella, Giardia, worms
example of diseases through contaminated blood/ fluids
Hep B/C
west nile
example of diseases through contaminated air
measles
TB
vector transmission
mechanical or biological
mechanical vector transmission
incidental, accidental transmission
example of mechanical vector transmission
flies on food
biological vector transmission
vector is required part of lifestyle
examples of biological vector transmission
malaria
lyme
plague
nosocomial infection
hospitals/ clinic acquired infections (HAI) 5-15% patients get, many die
types of microbes
types of patients
transmission
types of microbes
drug resistant, difficult to disinfect
example of types of microbes
mRSA, Pseudomonas, Enterococci, C. diff
types of patients
immunocompromised by illness, surgery, drugs, anesthesia, depression, ect.
transmission
invasive procedures
example of transmission
surgery, catheters, respiratory, IV
the top nosocomial bacteria
AIDS 1993
John snow
cholera
Ignaz Semmelweis
hand washing
Florence nightingale
typhus
clean linens
modern epidemiological agencies
CDC (center for disease control)
NIH (national institute of health)
WHO (world health organization)
index case
the first patient found in an epidemiological investigation
notifiable diseases
HIV/ AIDS
TB
measles
meningitis
hepatitis
gonorrhea
leprosy
EIDs
new disease or old diseases with increasing incidence or virulence
microbial evolution
human behavior
political upheaval and war
climate change and natural disasters
development into remote areas
global trade and travel
incidence
the fraction of the population that contracts a disease during a particular period of time
prevalence
the fraction of a population having a specific disease at a given time
sporadic
occurs occasionally in a population
endemic
confined to a particular country or area
epidemic
A widespread outbreak of an infectious disease.
pandemic
Disease that occurs over a wide geographic area and affects a very high proportion of the population.
bacteremia
presence of bacteria in the bloodstream
septicemia
growth of bacteria in the blood
viremia
viruses in the blood
toxemia
toxins in the blood
prodromal
early symptoms that may indicate the onset of a condition or disease
incubation
process to develop an infection
convalescence
gradual recovery after an illness
systemic infection
an infection throughout the body
secondary infection
opportunistic infection after a primary infection
innate immune system
1st line of defense: skin, mucous membranes, microbiota
2nd line of defense: natural killer cells and phagocytic WBCs
-inflammation, fever, antimicrobial substance
adaptive immune system
3rd line of defense:specialized lymphocytes: T cells+B cells
antibodies
physical Barries to infection
skin: keratinized cells
mucous membranes: sticky fluid traps
innate immunity
Immunity that is present before exposure and effective from birth. Responds to a broad range of pathogens.
normal flora
on the skin and mucous membranes compete with pathogens for space and nutrients some microbiota produce toxic compounds, acids, or antibiotics
protective chemical factors
pH: 5-6 skin, 1-2 stomach, 5 bladder, 3-5 vagina
salts on the skin: high osmotic pressure
lysozyme in body fluid lyses g+ cell walls
(most probiotics are lactobacillus and bifidobacterium)
cellular defenses in tissues
leukocytes
granulocytes
agranual cells
Leukocytes (White Blood Cells)
stained with wrights including eosin methyl blue, nuclei, strain purple
granulocytes
WBCs with granules in cytoplasm, multilines nuclei
eosinophils
basophils
neutrophils
eosinophils
orange granules w/ anti histamines, toxic chemicals from parasites, increases in parasites and allergies
basophils
deep blue granules containing heparin and histamine, increased in inflammation
neutrophils
binds to both dyes, granules are light pink, major phagocyte WBC in blood, can crawl out into tissue fight bacterial infections
agranual cells
monocytes
macrophage
natural killer (NK)
lymphocytes
dendritic
monocytes
single bent nucleus, immature phagocyte found in blood
macrophages
mature, activated phagocyte found in tissue
natural killer
kills above normal cells, not specific
lymphocytes
smaller specific cells
B cells: mature in bone marrow, produce antibodies
T cells: mature in thymus; kill bacteria virus infected or cancer cells; control immune response
dendritic
branched phagocyte in tissues, transport captured microbes to lymph nodes, activate adaptive immunity
inflammation
acute or chronic
local or systemic
antimicrobial chemicals
cytokines
interleukins
TNF
Interferons
cutokines
proteins which modify immune response
interleukins
produced by WBC, control WBCs
interferons
made by fibroblasts and WBCs
Alpha, beta, gamma
hepatitis, MS, cancer
Toll-like receptors
membrane receptors that recognize common part of microbes, each TLR bunds different danger signal; cause the release of inflammatory cytokines to alert the immune system
PAMP: pattern recognition
adaptive immunity
learned adaptations to specific infectious organisms. acquired over lifetime memory immunity
humoral immunity
provided by primarily B cells
antigens
antibody generator, any non self cells
epitopes
epitopes
specific parts of antigen that stimulates production of and bind to specific antibodies
antibodies
immunoglobulins (Ig) large globular proteins, produced by B cells lymphocytes progeny, bind specific antigenic determinants
antibody structure
quaternary
2 light chains 2 heavy chains joined by disulfide bonds
variable region
the region of antibody that binds specific epitopes
IgG
monomer, constitutes 80% of circulating antibodies, crosses placenta to fetus, diffuses into tissues, activates complement (c) long lived
IgM
pentamer, strongly agglutinates antigens, activates C, produced first in infections responsible for ABO blood grouping antibodies
IgA
dimer, specialized for secretions (breast, milk, saliva, ect.) and mucous membranes
IgD
monomer, found on B cell surface, involved in B cell activation and maturation
IgE
monomer, binds to mast cells and basophils, causes histamine release in inflammation
primary antibody response
primary exposure
relatively slow increase (7-10 days)
IgM first IgG second
low titers [Ab]
organism has time to cause dimers
secondary antibody response
subsequent exposures
quicker increase (1-3 days)
primary IgG
high titers [Ab]
organism is cleared before it causes disease
B cell development stages
B stem cells produce bone marrow
Naïve B cells
mature B cells
Plasma cells
memory cells
Naïve B cells
circulate in blood lymph with a specific receptor IgD
"looking" for matching Ag
Mature B cells
has encountered its matching Ag selected to survive, proliferate, become clonal army
plasma cells
Ab factories that can secrete thousands of soluble Ab/ second short lived
B cell stimulation/ activation
2 types of Ag stimulate B cells to become plasma cells and produce soluble Ab
T- independent Ag
can stimulate B cells to become plasma cells without the help of T cells
low titer IgM early response
example of T-independent antigen
capsule
LPS
T-dependent antigens
require help from T cells and Ag presenting cells (APC)
mostly proteins stronger, long lasting, IgG response
cells required for T- dependent antigens
helper T cells
APCs
Helper T cells
have specific receptors (TCR) that recognize particular antigens produce cytokines to increase immune response
APCs
macrophages digest foreign Age and display them in cell surface proteins called major histocompatibility complex (MCH)
MCH class I
self Age found on all nucleated cells, identifying cellular dog tags, passports, or bar code
MCH II
found only on immune cells used for foreign Ag display
T cells
naïve cells leave bone marrow to get their antigen education in thymus
All T cells have specific TCR
2 types of T cells based on function and membrane CD antigens
helper t cells (CD4+)
recognize foreign Ag in MHC II produced by cytokines
Increases immune response
Cytotoxin T cells (CD8+)
recognize abnormal Ag in MHC I, induce apoptosis or lysis or cancerous, virus infected or foreign cells
use perforin and granzyme
non specific antigen presenting cells: APCs
macrophages: use MHC II to stimulate both B and T cells locally
dendritic cells
dendritic cells
mobile phagocytes that transport Age to lymphoid tissues (nodes spleen) stimulate both CD4+ and CD8+ T cells by presenting Ag MHC II and MHC I
natural killer cells (NK)
non-specific don't have IgD or TCR
use antibody dependent cellular cytotoxicity to attack worms, cancerous virally infected transplanted cells
Ehrlich
"magic bullet"
salvarsan vs syphilis
arsenic
domagk
first sulfa drug
prontonsil vs staph+strep
fleming
penicillin by mistake
Waksman
streptomycin vs tb
first use of the word "antibiotic"
Chain and Florey
eating and production of penicillin
true antibiotic
produced naturally by soil microbes, only works against bacteria
fungi that produces antibiotics
cephalosporium
penicillin
bacteria that produces antibiotics
streptomyces
bacillus
synthetic antimicrobials
produced in lab
semisynthetic drugs
chemically altered antibiotics
broad spectrum drugs
works against almost all microbes
narrow spectrum drugs
works against targeted few microbes
Bacteriocidal
kills bacteria
bacteriostatic
inhibits bacterial growth
beta lactam rings
All members of the penicillin family have
beta lactamase
An enzyme produced by certain microorganisms that has the ability to cut the ring and inactivate the drug
Drugs that inhibit cell wall synthesis
penicillin
cephalosporin
bacitracin
vancomycin
isoniazid
Drugs that inhibit protein synthesis
Amino-glycosides
Tetracyclines
Chloramphenicol
erythromycin
clindamycin
drugs that inhibit nucleic acids and mitosis
rifampin
fluoroquinolone
quinines
griseofulvin
nucleoside analogs
drugs that inhibit enzymes
metronidazole
mebendazole
sulfonamides
trimethoprim
amantadine
saquinavir
drugs that disrupt plasma membranes
polymyxin B
azoles
Amphotericin B
synergism
combination of two drugs causes an effect that is greater than the sum of the individual effects of each drug alone
susceptibility testing
tests the sensitivity of bacteria to different drugs when empiric therapy doesn't work
Kirby bauer disk diffusion
bacterial lawn are exposed to rx in filter paper disks
zone of inhibition measure in mm
zone diameter related to sensitivity
QUALTITATIVE
Minimum inhibitory concentration (MIC)
serial dilutions of Rx find least amount that sill works
QUANTITATIVE
E-Test
Epsilometer strip has concentrations of Rx
can be used to determine MIC
QUANTITATIVE
the 4 drug resistance mechanism
1. drug can't penetrate the cell
2. drug is destroyed by microbial enzyme
3. drug target is altered so it no longer binds drug
4. drug is quickly removed from the cell (efflux)
drug can't penetrate the cell example
porin, block gentramycin
drug is destroyed by microbial enzyme example
penicillinase cleaves penicillins
drug is target is altered so it no longer binds drug example
50s won't bind erythromycin
drug is quickly removed from the cell (efflux) example
pump out tetracycline
common drug resistant organisms
staphylococcus
neisseria
mycobacteria
streptococcus
clostridium
acinetobacter
klebsiella
pseudomonas
what is a vaccine
inoculation with a form of organism which induces immune response, but doesn't cause the disease
what are the four classes of vaccines
attenuated/ live
inactivated/killed
subunit
toxoid
(experimental vaccines)
attenuated/ live vaccines
organism is weakened
replicated in the host
subclinical infection
lifelong immunity
example of attenuated vaccines
MMR
chicken pox
TB
sabin (oral) polio
Inactivated killed vaccines
organism is dead
doesn't replicate in host
safer
may require boosts
Examples of inactivated/killed vaccines
seasonal flu
Salk (inject) polio
rabies
subunit vaccines
only part of organism injected
may be conjugated (bound) to larger protein
safe
example of subunit vaccine
Hepatitis B
Haemophilus influenzae (Hib)
HPV
Pneumococcal
meningococcal
pertussis
toxiod vaccines
inactivated toxic of microbe
requires boost
example of toxoid vaccine
tetanus
diptheria
what disease does DTaP protect against?
diphtheria
what disease does IPV protect against?
polio
what disease does MMR protect against?
measles, mumps, rubella
what disease does PCV protect against?
Streptococcus pneumoniae
what disease does Hib protect against?
Haemophilus influenzae type b
what disease does Var protect against?
varicella
what disease does Hep A/B protect against?
hepatitis A/B
what disease does HPV protect against?
human papillomavirus
what disease does Rota protect against?
rota virus
what disease does MCV protect against?
meningitis
herd immunity
The resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune
direct agglutination tests
detects Ab-Ag complexes directly
may be difficult to see without a microscope
indirect agglutination tests
uses latex beads to magnify agglutination
can see with naked
agglutination tests
used to detect microbial antigens or patient antibodies
antibody titer
concentration of antibody in serum
hemagglutination inhibition tests
measles, mumps, influenza viruses agglutinate RBCs
patient with AB to these viruses block agglutination
lack of agglutination is a positive test for antibody, which indicated infection (or immunization)
fluorescent antibody tests
fluorescent antibodies used to visualized microbial Ag or anti microbe Ab
direct fluorescent antibody tests
detects microbial Ag in patient specimen
indirect fluorescent antibody tests
detects anti-microbe AB in patient plasma
uses sandwich technique with fluorescent anti-human IgG as second Ab
enzyme linked immunosorbent Assay (ELISA)
versatile, easy, cheap, fast, can test patient for antigen (direct) or antibodies (indirect)
uses enzyme bound to antibodies which produce a colored product can see with naked eye
example of ELISA
HIV tests: Indirect ELISA
pregnancy
rapid strep
complement fixation
An immune response in which antigen-antibody complexes activate complement proteins.
western blot test
used as a confirmation test for anti- HIV antibodies
gold standard for HIV infection
electrophoresis separation of HIV epitopes blotted to paper strips, mixed with patient serum, visualize binding with anti-human IgG dye
hypersensitive disorder
overreaction of immune system
what are the 4 types of hypersensitivity
anaphylactic, cytotoxic, immune complex, delayed cell-mediated
anaphylactic reactions
IgE binds mast cells or basophils, degranulate, release histamine, leukotrienes and prostaglandins, resulting in inflammation
may be mild (local) or life threatening (systemic) within minutes
BV dilation ( lowers BP shock), increased mucous secretion, respiratory smooth muscle contraction
example of anaphylactic reaction
hay fever
skin rashes
asthma
anaphylactic shock
medication for anaphylactic reactions
antihistamines
steroids
epinephrine
cytotoxic reactions
IgM or IgG binds cells, activate complement, cause cytolysis within minutes to hours
example of cytotoxic reaction
ABO blood groups based on carbohydrate antigens on RBCs. Plasma contains IgM antibodies to opposite antigens. No previous exposure required

Rh blood grouping based on the presence or absence of Rh (rhesus) antigens on RBCs. Rh reactions do require previous exposure (transfusion or pregnancy
Rh negative mothers can produce anti-Rh IgG when delivering Rh + babies. May cause HDN (hemolytic disease of newborn) in next baby RhoGAM (passive immunity)
immune complex reactions
IgG bound to Ag (=Ab-Ag complex) gets stuck in tissues, activates complement. serve inflammatory reaction, tissue damage. start within hours, damage may be permanent
example of immune complex
glomerulonephritis, rheumatoid arthritis
cell mediated reactions
cells do the damage, not Ab T helper (CD4+) release cytokines, cause inflammation 1-2 days after exposure (delayed hypersensitivity)
examples of cell mediated reactions
TB skin test: + indicates exposure not disease
contact dermatitis: poison ivy or oak
tissue transplant rejection: cytotoxic T cells (CD8+)
autoimmunity
hypersensitivity against self
type I diabetes
cytotoxic T cells destroy pancreatic islet cell, no insulin, high plasma glucose
graves disease
antibodies bind, stimulate thyroid; result in hyperthyroid, goiter, bulging eyes, high heart rate
multiple sclerosis
T cells destroy myeline sheath on nerves; sensitivity, progressive muscle weakness
systemic lupus erythematosus (SLE)
antibodies to own DNA and nuclear membranes; result in immune complex build up, inflammation in kidney, joint, skin
myasthenia gravis
antibodies that coat the acetylcholine receptors at the junction at which nerve impulses reach the muscles
immunodeficiency
low immune response
congenital deficiency
genetic primary defects
examples of congenital deficiency
agammaglobulinemia: B cell defect
DiGeorge's syndromes: T cell defect
chediak higashi disease: phagocytic cell defect
SCID: lymphocyte stem cell defect
acquired immunodeficiency
environmental secondary factors
examples of acquired immunodeficiency
chemotherapy and radiation: lower bone marrow
immunosuppressive RX: transplants/ inflammation
infectious disease: measles, HIV
emotional stress: stress hormones (high cortisol)
diet: insufficient protein less Ab produced
advanced age: memory cells die off
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