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Med Micro
Exam 4
| Question | Answer |
|---|---|
| immunity | the condition in which an individual is protected form a certain disease...it is dependent on the presence of antibodies, T lymphocytes, and other immune system factors |
| vaccines | a killed or altered form of a pathogen is introduced into the human blood stream....generates a primary immune response, leads to the formation of antibodies and long term memory cells |
| how do vaccines work | if the vaccine recipient encounters the real, live pathogen, the memory cells are stimulated and a rapid secondary immune response is activated (mimics the immunity gained fromnfighting the disease) |
| attenuated whole agent viruses | works the best! use a living but weakened form of the virus. Can mimic the infection and give lifelong immunity without booster immunizations...they can also replicate in the body and stimulate the secondary response |
| drawbacks to attenuated whole agent vaccines | expensive to produce, not recommended for people with compromised immune systems |
| example of attenuated vaccine | MMR (measles, mumps, rubella) |
| inactivated whole agent vaccines | the pathogen is killed using chemicals, heat or radiation-----the deactivated particles are in the vaccine--provides a weaker immune response so you will need booster shots, but they are safer than the attenuated vaccines |
| drawbacks to inactivated whole agent vaccines | not as strong of an immune response, needs boosters |
| examples of inactivated whole agent vaccines | rabies and influenza |
| toxoid vaccines | inactivated toxins that are directed at the substances produced by a pathogen---used in some bacterial diseases where a toxin is the main cause of illness |
| examples of toxoid vaccines | tetanus and diphtheria (parts of Childhood vaccines) |
| Subunit vaccines | only use antigenic fragments of a microbe and are often produced through recombinant DNA technology basically.....take a normal cell and make it display a viral antigen to stimulate an immune response. |
| pros of subunit vaccines | they are safer because they cannot reproduce in the host......they also tend to produce fewer adverse side effects |
| example of subunit vaccine | hepatitus B vaccine |
| conjugate vaccine | a type of subunit vaccine that combines a weak antigen with a strong antigen carrier to incite a stronger immune response. the carrier protein is attached to the antigen when the antigen itself is not strong enough to stimulate enough response |
| example of a conjugate vaccine | Hib vaccine for meningitus |
| Nucleic acid vaccines | involve the injection of a plasmid of DNA into muscle....produces the protein antigen of the virus, carried to the bone marrow to stimulate both moral and cellular immunity/// typically given to animals |
| drawbacks of Nucleic acid vaccines | many side effects, can train the body to attack its own cells |
| example of nucleic acid vaccine | Covid vaccine (mRNA vaccine) |
| Herd immunity | the idea that controlling a disease does not necessarily require that everyone be immune, most of the population (90%) is vaccinated,,,enough to prohibit outbreaks because not enough individuals to support the spread of epidemics |
| immunopathology | the study of disease states associated with over-reactivity or under-reactivity of the immune system |
| over-reactivity (hypersensitivity) | these are allergies and autoimmune disorders...the host tissues are attacked by its own immune system that can't distinguish self from non self |
| immunodeficiency (hyposensitivity) | immune function is incompletely developed, suppressed, or destroyed |
| Hypersensitivities | uncomfortable, adverse, and sometimes fatal reactions to antigens produced by the regular immune system, often get worse with each new exposure |
| autoimmune disorders | failure to recognize self-antigens |
| immunodeficiency disorders | deficiency in the immune response |
| allergy | the exaggerated immune response that is manifested by inflammation |
| allergen | the antigen that causes the hypersensitivity |
| inhalant | airborne allergies (pollen, dust etc) |
| ingestants | food allergies |
| injectants | drugs, vaccines, and insect stings |
| Contactants | skin contact (cosmetics, latex, metals, detergents) |
| Atopy | any chronic local allergy such as hay fever or asthma |
| Anaphylaxis | a systemic reaction that can involve airway obstruction and circulatory collapse |
| Type 1 hypersensitivity | IgE mediated anaphylactic |
| Type 2 hypersensitivity | Cytotoxic |
| Type 3 hypersensitivity | Immune Complex |
| Type 4 hypersensitivity | Delayed Cell-mediated |
| step one of type 1 hypersensitivity | sensitization--the first time an allergen meets the immune system, no allergic reaction occurs but the body prepares itself for future contact with the allergen...B cells recognize the antigen and make IgE antibodies that attach to mast cells/basophils |
| step two of type 1 hypersensitivity | mast cell activation- a later encounter with the allergen, reaction occurs within minutes of contacting the allergen. IgE antibodies on mast cells recognize the antigen and bind to it...the granules in the mast cell release contents----HISTAMINE! |
| results of histamine release from mast cells | increase mucus production, causes redness/swelling/inflammation |
| results of release of prostaglandins from mast cells | constrict airways and enlarge blood vessel |
| Hay fever (allergic rhinitis) | allergic reaction of the nasal passages caused by pollen, dust, animal dander, etc |
| Asthma | common chronic inflammatory disease of the airways characterized by wheezing, coughing, chest tightness, and shortness of breath |
| Eczema | inflammation of the skin (redness, skin swelling, itching, dryness, crusting, flaking, blistering, cracking, oozing, or bleeding |
| systemic anaphylaxis | sudden, whole-body allergic reaction that can be life threatening (unconsciousness, edema, rashes, cramps, and shortness of breath can develop) |
| Potential anaphylactic reactions | can be caused by food allergies, insect allergies (bee stings), drug allergies (antimicrobials, aspirin, opiates, and contrast dye for MRIs) |
| Cytotoxic hypersensitivities | generally involve the activation of the complement system by combination of IgM or IgG antibodies with antigenic cell...lyses the cell which may be a foreign cell or a host cell with a foreign antigenic determinant on its surface |
| common type 2 hypersensitivity | transfusion reactions..blood cells are destroyed as a result of reacting with circulating antibodies (incompatible transfusion) the antigen-antibody reaction triggers the complement system which destroy the donor's RBCs as they enter the bloodstream |
| another example of type 2 hypersensitivity | Rh- mother with Rh+ baby....specifically a second child with this scenario...the mother produces anti Rh antibodies against the baby's Rh + antigens...can cause jaundice and severe anemia in the baby |
| immune complex hypersensitivities | antibodies against soluble antigens in the serum...when IgM and IgG antibodies form complexes with the antigen...they clump up get deposited into organs... cause inflammatory damage.... immune system tries to dissolve complexes but causes tissue damage |
| delayed cell-mediated hypersensitivity | involve cell mediated immune responses and are caused mainly by T cells, occur a day or so later...delay is the time needed for T cells and macrophages to accumulate at the site of the foreign antibodies |
| examples of type 4 hypersensitivities | latex, poison ivy, cosmetics, and metals in jewelry can cause delayed cell mediated hypersensitivity reactions |
| transplants | get rejected when the immune system interprets the tissue as non-self (dependent on MHC proteins...need to have as close of a match of MHC proteins as possible--better chance for success) |
| types of transplants | autografts, isografts, allografts, xenografts |
| autografts | graft taken from one part of a body and put in another place in the same body |
| isografts | graft given from one identical twin to another |
| allografts | grafts between members of the same species |
| xenografts | grafts between members of different species |
| autoimmune disorders (loss of self-tolerance) | results when the immune system attacks its own self antigens and causes damage to ones organs (75-80% are in women) the immune system cannot distinguish self from non-self |
| cytotoxic autoimmune reactions | involve antibody reactions to cell surface antigens, although there is no cytotoxic destruction of the cells....(Graves disease and Myasthenia gravis are examples) |
| immune complex autoimmune reactions | involve antibodies directed at components of their own cells including DNA which is probably released during the normal breakdown of tissues...the immune complexes are deposited in tissues and cause damage (examples : Lupus/Rheumatoid arthritis) |
| how does lupus work | the complexes get deposited in the kidneys |
| how does rheumatoid arthritis work | the complexes get deposited in the joints |
| cell mediated autoimmune reactions | example --Multiple sclerosis is a neurological disease in which T cells and macrophages attack the myelin sheath of nerves |
| immunodeficiencies (2 kinds) | the absence of a sufficient immune response which can be either congenital or acquired |
| congenital (primary) immunodeficiency | people are born with, usually as a result of defective or absent genes |
| acquired (secondary) immunodeficiency | those caused by a variety of drugs, cancers, or infectious agents......AIDS is an example |
| main methods of identification | Phenotypic (morphology/ physiology/ biochemistry) or Immunological (serological analysis) or Genotypic (genetic techniques) |
| Phenotypic Methods | observation of microbial traits like cell size and shape...staining helps determine other features (Gram/ endospore)...use electron microscopy to find cellular projections, look at colony shape, growth rate, ability to ferment, sensitivity to antibiotics |
| Immunological Methods | the presence of a certain antibody to a particular antigen is looked for when trying to diagnose the source of an infection, can be easier than finding the microbe itself |
| Genotypic Methods | involve examining there genetic material directly. Don't always have to grow colonies of the bacteria...getting increasingly automated, can produce rapid results |
| Collecting Specimens | must be aseptic! need to be labeled and handled correctly, kept at right temperatures...typically some form of bodily fluid |
| Direct examination | direct microscopic observation is one of the most rapid methods for determining presumptive microbial characteristics (using Gram stain and Acid-fast stain commonly) |
| Cultivation | use differential and selective medias to only grow suspected pathogens (can use blood agar, fermentation patterns determined by MSA or MacConkey agar) |
| Biochemical testing | physiological reactions of bacteria to nutrients and other substrates (see what enzymes are present) can be seen in color changing strips (Api20e multiple system tests)...time and cost effective |
| Genetic probes | using a probe (a small piece of RNA or DNA to sample microbial DNA for complementary sequences.....complementary sequences will bind and can be seen with luminescence |
| PCR | used to amplify a sample genome and can sequence it to identify the microorganism |
| serology | based on the principle that antibodies are extremely specific for antigens...they bind precisely and reliably -----can either use an antibody to identify an antigen or use the antigen to identify the antibody |
| what do you test with serology | can test serum, urine, CSF, whole tissues, and saliva |
| monoclonal antibody test | a collection of identical antibody molecules that are derived from a single B-cell hybridoma clone (a B cell fused to tumor cell for immortality.....makes antibodies all the same) these antibodies are highly specific and can be made in large quantities |
| drugs ending in "mab" | are made with monoclonal antibodies |
| can screen using antibodies | used to test for presence of specific proteins or hormones (in pregnancy test) or for the presence of bacterial pathogens |
| precipitation reactions | involve the reaction of SOLUBLE antigens with IgG or IgM antibodies to form interlocking aggregates (lattices) ....measure an antigen or antibody in bodily fluids (see visible precipitation in solution) |
| applications of precipitation reaction | a blood specimen is mixed with test antigens to find patient antibodies...typically for suspected fungal infections |
| agglutination reactions | uses whole cells (RBCs) or organisms like bacteria and viruses that display surface antigens...the antigens get linked together by antibodies to form visible aggregates (agglutination) |
| many types of agglutination reactions | direct agglutination, hemagglutination |
| direct agglutination | detect antibodies against cellular antigens like the ones on RBCs, fungi, and bacteria------determine antibody titer |
| antibody titer | the amount of antibody within serum (high titer means more antibodies and more immunity to the disease) |
| hemagglutination | the clumping of RBCs and are routinely used in blood typing...use RBC surface antigens and their complementary antibodies |
| Neutralization reactions | mixing cells with a toxin that would normally kill them, but also include presence of an antibody and cells will live...the antibodies neutralize the toxin |
| Fluorescent antibody (FA) techniques | can be direct or indirect |
| direct FA test | used to identify a microorganism in a clinical specimen...the specimen containing the antigen is fixed to the slide and then treated with a fluorescent labeled antibody...if it binds to the antigen, it will be seen under fluorescent microscope |
| indirect FA test | used to detect a specific antibody in serum following exposure to a microorganism...uses fluorescent labeled antibodies that will bind to the antibodies produced by the patient against the microorganism ....it is much cheaper than direct FA |
| skin is the largest organ of the body | is 10% of a person's body weight (from 1.5mm to 4mm) |
| integumentary system | skin, hair, nails, sweat, and oil glands |
| skin has two parts | epidermis and dermis |
| epidermis | the outermost portion of skin (4-5 layers of epithelial cells) has many rows of dead--keratinized and waterproof cells (cells are lost and replaced every 25-45 days) |
| dermis | the inner, relatively thick portion of skin....mainly connective tissue (where the hair follicles, sweat gland ducts, sebaceous glands are...they provide passageways for microorganisms to enter through the skin's barrier) |
| skin cells fall off by the millions | they take the microorganisms with them |
| the skin has many antimicrobial substances | antimicrobial peptides disrupt the membranes of bacteria////Sebum (mix of lipids, proteins, and salts) keep the skin and hair from drying out...has low pH to make it unhospitable to microorganisms |
| perspiration | provides moisture and some nutrients for bacterial growth, but is salty and lowers pH...also contains lysozyme that kills many bacteria by breaking down peptidoglycan |
| lysozyme | found in sweat, saliva, and tears....kill bacteria by breaking down peptidoglycan |
| microbes of the skin | more resistant to drying out and are more ok with high salt conditions normal microbiota has many gram positive bacteria |
| microbes are more plentiful in areas of higher moisture | lots of populations in the armpits and groin...they metabolize the secretions from sweat and cause body odor |
| normal microbiota of the skin | Streptococcus, Staphylococcus, Propionibacterium, Corynebacterium, the fungus Malazzezia, Gram negative rods---Pseudomonas and Janthinobacterium |
| Maculopapular rash diseases | diseases that present with rashes that are flat to slightly raised colored bumps |
| measles | Maculopapular--a virus of the Morbillivirus genus (ssRNA enveloped virus)...kills hundreds of thousands of kids in developing countries (vaccine is available!!) symptoms are sore throat, dry cough, fever...get Koplik's spots in mouth--- spread to all body |
| measles is one of the most contagious infectious diseases | transmitted primarily by respiratory droplets....humans are the only reservoir many people with measles will develop a secondary infection |
| the MMR vaccine | contains live attenuated measles and rubella virus, protects you for about 20 years |
| Rubella (German measles) | maculopapular--caused by Rubivirus (ssRNA enveloped virus) a relatively minor rash with few complications (pink spots that start on the face and spread to rest of body....lasts for three ish days) infection by contact with respiratory secretions/urine.. |
| Adult Rubella | can often manifest as joint inflammation rather than a rash |
| transmission of rubella to fetus | can result in serious complications ----congenital rubella if in first trimester can cause miscarriage or permanent defect (deafness) humans are the only reservoir |
| fifth disease | maculopapular---a mild disease that results in "slapped-cheek" appearance on the face...rash comes to rest of body...is very contagious but there is no vaccine or treatment because it is very mild |
| roseola | maculopapular---caused by human herpesvirus (HHV-6) common disease in young children/babies....can be seen with or without the rash and can have fever ....thought that 100% of people have had it by the time they are an adult...no vaccine or treatment |
| scarlet fever | maculopapular--a bacterial illness that comes along with strep throat, a bright red rash covers most of the body with a high fever and sore throat....can be treated with antibiotics, no longer life threatening |
| impetigo | maculopapular--a bacterial infection (caused by Staph aureus or Strep pyogenes) that causes the skin to flake and peel off, highly contagious, mainly in children...around mouth, face and extremities |
| cellulitis | maculopapular--condition caused by fast spreading infection of the dermis and subcutaneous tissues.....from a fungal or bacteria(S aureus and S pyogenes) enter by trauma to skin.... more common in immunocompromised patients |
| pustular rash diseases | rash with fluid-filled welts |
| chicken pox | pustular---caused by Varicella virus (enveloped DNA virus) has 10-20 day incubation, fever and rash on scalp and face to rest of body...lasts from 4-7 days, the lesions crust (yes a vaccine!) |
| shingles | pustular---the Varicella virus migrates to regions of skin by cutaneous nerve branches...goes latent and can become reactivated by drugs, stress, surgery, etc |
| small pox | pustular--- either Variola minor or major virus (enveloped DNA ) ...-no longer naturally occuring, get fever and malaise with large rash in pharynx to face and extremities (do have vaccine but no treatment) spread through droplets and fomites (bedding) |
| warts (papillomas) | another microbial skin disease.... caused by one of 100s of Human Papilloma Virus (HPV) almost everyone gets them! |
| common warts | painless, elevated rough growths on fingers and other parts of the body |
| plantar warts | deep, painful papillomas on the soles of the feet |
| flat warts | smooth skin colored lesions on the face, trunk, elbows and knees |
| leishmaniasis (leishmania is the protozoan) | a zoonosis transmitted among various mammalian hosts by female sand flies, transmitted by a sand fly when it ingests host blood---happens in equatorial regions where the sand flies live...there is no vaccine! |
| cutaneous anthrax | the most common and least dangerous version of infection caused by Bacillus anthracis..........caused by endospores entering the skin by small cuts and abrasions....can be fatal 20% if the time....was used in bioterrorism |
| mycoses | a group of disease caused by fungi....ringworm is limited to nonliving epidermal tissues (hair and nails)...treatment is anti fungal agent |
| locations you can get ringworm | scalp (tinea apiitis) /beard (tinea barbae)/ body (tinea corporis)/ groin (tinea cruris) / foot (tinea pedis)/ hand (tinea manuum).....the agent to cause it differs by location |
| causes of ringworm | typically members of Trichophyton, Microsporum, or Epidermophyton |
| two parts to the nervous system | the central nervous system (CNS) and the peripheral nervous system (PNS) |
| the brain and the spinal cord | CNS, they are dense structures made up of cells called neurons, Brian is in skull and spinal cord is in vertebral column |
| soft tissue of brain and spinal cord are surrounded by meninges | there is CSF in the two inner layers of meninges to cushion and nourish the brain and spinal cord...the meninges are a common site of infection---can often find microbes in the CSF |
| the defenses of the nervous system | mainly structural (bony casings and cushioning CSF) |
| the blood brain barrier | prohibits microorganisms from passing into the CNS...cells of the blood vessels allow VERY few molecules to pass through..provides an additional layer of protection |
| immunologically privileged sites | CNS, uterus, parts of the eye...these areas can only mount a partial immune response when exposed to antigens...dont want to damage these important tissues |
| microglia | act as the special phagocytic cells of the CNS, but are less phagocytic than the other phagocytes of the body |
| microbiota in the CNS or PNS??? | NONEEEEE |
| Meningitis | inflammation of the meninges, caused by many different microorganisms--the most acute are caused by bacteria, but their entrance to the CNS is probably through a respiratory virus?! results in headache, pain in neck, fever, nausea, or vomiting |
| testing for meningitus | do a lumbar puncture to get CSf, do a gram stain on the serum, or a culture |
| Neisseria meningitidis (meningococcus) | a gram negative diplococci...associated with endemic forms of meningitis...causes the most severe forms of acute meningitis...the bacteria release a toxin that is a stimulus for WBCs \---causes petechiae |
| cause for petechiae | damage to blood vessels caused by cytokines released by WBCs leading to vascular collapse, hemorrhage, and lesions called petechiae |
| signs of meningitis caused by Neisseria... | is sudden onset, high fever, sore throat, delirium, bleeding under skin, shock, coma....intravasular clotting, cardiac failure, death can occur in hours!!!..spread through droplets, mostly when carriers live in close quarters with non-immune individuals |
| Streptococcus pneumonia | can also cause meningitis, frequent cause and very severe....does not cause petechiae....there is a vaccine (Prevnar is part of childhood immunizations) |
| Haemophilus influenzae | can also cause meningitis...very severe...was a common cause of death before the Hib vaccine came out in 1988 |
| Listeria monocytogenes | can also cause meningitis...a gram positive coccobacillus with 1-4 flagella, grows inside host cells....often mild in healthy adults, but causes meningitis or death in elderly or immunocompromised---pregnant ..give it to baby...typically results in death |
| Cryptococcus neoformans | a fungus that causes chronic meningitis with gradual onset of symptoms...headache, nausea, stiff neck....PIGEONS!! it is an opportunistic pathogen, most healthy individuals fight it off just fine |
| Coccidiodes species...... | found in the soil and can cause meningitis (C. immitis in San Joaquin valley/ C. posadil in US southwest, Mexico, and South America) comes up with farming, archaeological digs, construction and mining |
| viruses that cause meningitis | viral meningitis is mostly in children...generally milder than bacterial or fungal meningitis and is over in like 2 weeks |
| neonatal meningitis | results by infection of mother given to baby in utero or by passage through birth canal...most common are Strep agalactiae (in 10-30% of female genital tracts) and E. coli....can be severe! death happens 20% of the time |
| Poliomyelitus (Polio) | an acute enteroviral infection of the spinal cord that can cause neuromuscular paralysis, can be contained as short term viremia |
| if viremia persists.... | viruses can be carried the to CNS through blood and can attack motor neurons of the spinal cord---paralysis of legs/abdomen/back/bladder....motor sensation is affected, but not pain sensation....often very painful!! |
| how is Polio transmitted | virus passes through population by feces contaminated water, food, hands, etc... has been irradiated from western hemisphere, but not from developing world. |
| vaccines for Polio | 1) inactivated polio vaccine (IPV)...by Jonas Salk 2) oral polio vaccine (OPV).....by Albert Sabin |
| encephalitis | inflammation of the brain and is caused by viral infections....signs are behavior changes or confusion because of inflammation (decreased consciousness and seizures) |
| arthropod borne viruses (arboviruses) encephalitis | like West Nile virus.....arboviral encephalitis begins with a bite, release virus into host, replicates in lymphatic tissues...coma, paralysis, tremor, memory deficits, heart disorders....no good privation! keep mosquitoes away |
| Toxoplasma gondii...intracelular parasitic protozoan | a parasite that can attack over 200 birds and mammals...primarily in cats.....gets in mice, mice not afraid of cats! Congenital transmission in first or second trimester is stillborns or severe abnormalities |
| rabies | slow progressive zoonotic disease characterized by fatal encephalitis incubation of 1-2 months...humans don't survive until recently with intensive treatment...need a post exposure vaccine before symptoms begin |
| tetanus | a neuromuscular disease caused by Clostridium tetani......a gram positive spore forming rod that releases a strong toxin called tetanospasmin! |
| tetanospasmin | binds to target sites on peripheral motor neurons, spinal and brain, and in the sympathetic nervous system by blocking inhibition of muscle contraction...muscles contract uncontrollably...spastic paralysis. |
Created by:
Gracie Cook
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