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113 Cards in this Set
- Front
- Back
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Prophylaxis
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use of a drug to prevent imminent infection of a person at risk
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Semisynthetic Drugs
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drugs that are chemically modified in the lab after being isolated from natural sources
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Synthetic Drugs
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drugs produced entirely by chemical reactions
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Spectrum
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Narrow & Broad- antimicrobials effective against an array of microbial types
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Primary sites of action of antimicrobial drugs on bacterial cells
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cell wall
cell membrane DNA/RNA Ribosomes Folic Acid |
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Inhibitors of protein synthesis
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work at level of ribosome, 70S ribosomes not 80S
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Cell wall inhibitors
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block synthesis and repair
ex: penicillin, bacitracin |
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Folic acid synthesis
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inhibits metabolism
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Anitmicrobial resistance
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requires a change in the DNA
-mutation, horizontal transfer between species, transformation, transduction, conjugation |
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Acquired Drug Resistance Mechanisms
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drug inactivation
decrease permeability drug pump change in binding site use of alternative metabolic pathway |
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drug inactivation
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microbe makes an enzyme that cleaves a portion of molecule and changes it (becomes inactive)
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decrease permeability
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receptor that transports the drug is altered, so the drug cannot enter the cell
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drug pump
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specialized membrane proteins are activated and continually pump the drug out of the cell
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change in binding site
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binding sie on target (ribosome) is altered so drug has no effect
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use of alternative metabolic pathway
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drug blocked pathway, so microbe uses unblocked pathway
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Nosocomial infections
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infections you get in a hospital/ other healthcare facilities
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drugs in animal feed
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decrease infection and increase growth rate
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Strategies to limit drug resistance
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-physicians must make correct diagnosis and prescribe the right drug
-patients must follow recommendations for taking the drug -take 2 or more drugs |
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Drug Research
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-develop shorter term, higher dose microbial's that are less expensive, more effective, and fewer side effects
-develop new antimicrobials |
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Antibiotics
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do not get rid of infection, but buys time
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5 Long Term Strategies
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1. Proposal to help educate workers to encourage patients to take all antibiotics
-proposal that all doctors must justify each antibiotic prescription 2. valuable antimicrobials may be limited in use to only 1 or 2 types of infections 3. banning the use of antibiotics in animal feed 4. make effective therapy to low income populations 5. recommending vaccines as an alternative |
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Probiotics
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contain living cultures and will supplement normal flora and help protect from digestive upsets and sometimes work
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Prebiotics
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nutrients to encourage growth of microbes
ex: Cranberry Juice |
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3 Interactions between drug & host
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Selective Toxicity
Allergic Reaction Alternation of Microbiota |
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Selective toxicity
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want a microbe that will kill disease with no side effect, may be toxic to kidneys, organ, liver, etc
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Allergic Reaction
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Unpredictable, have to be exposed twice
ex: skin rash |
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Alternation of Microbiota
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microbes that normally live on/in you to protect them from infection, if wiped out other things can grow
ex: Yeast infection |
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Selecting antimicrobial drug
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-what is the microbe causing infection
-degree of microorganisms sensitivity to various drugs -overall medical condition of patient |
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Kirby-Bauer Disc diffusion test
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senses sensativity
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Kirby-Bauer Disc Steps
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-take pure culture and spread on dish
-take disc covered in antibiotic -antibiotic diffuses out of disc and onto pure culture -clear path by disc of antibiotic worked -bigger the zone, better it worked (measure with ruler and view chart) |
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Minimum Inhibitory Concentration
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-same amount of bacteria in each test tube, add drug
-when turns purple, that is the min amount of dosage needed |
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Actions of antiviral drugs
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-inhibit attachment/entry
-inhibition of nucleic acid synthesis -inhibition of viral assembly or release |
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2 Pathogenic microbes
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opportunistic
frank/true |
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opportunistic
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will not make you sick, but if you give opportunity they will cause and infection
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frank/true
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not part of normal flora, comes from outside and sets up infection
ex: flu, herpes |
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normal flora
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large and mixed collection of microbes adapted to the body
include array of bacteria, fungi, protozoa, and certain extent of virus's and arthropods |
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how do babies pick up normal flora?
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right out of birth, from food, and other people touching them
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host defenses
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healthy, nourished, vaccinated
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microbial virulence factors
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ability to establish in host and cause damage
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Virulence
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determined by its ability to establish itself in the host and cause damage
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Human host and microorganism outcomes
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-microbe passes through unnoticed
-microbe becomes established without disease -microbe causes disease |
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Factors that weaken host defenses
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old age, genetic defects, surgery/operations, underlying disease, chemotherapy, physical, and mental stress
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terminology
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itis: inflammation
emia:in the blood osis: disease cause oma: swelling |
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infected host
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exit, mode of transmission, entry to susceptible host
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susceptible host
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able to catch disease
-overcome host defenses -cause damage to host -become infected host |
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fomites
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anything that is not alive
ex: fork, pen |
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reservoir
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detour for the microbe
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biological reservoir
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alternate host, ex: deer for lymes
carriers: have infection but no signs/symptoms zoonotic: diseases of animals |
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nonbiological reservoir
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soil, water
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Symptoms
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non quantifiable
ex: nauseous, |
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Signs
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Quantifiable
ex: blood pressure, temperature |
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Classic stages of clinical infections
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incubation period, prodromal stage, period of invasion, convalescent period
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Incubation period
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initial exposure to microbe, infected but no signs or symptoms
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prodromal stage
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mild symptoms
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active/period of invasion
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microbe has invaded, is growing, body trying to fight it off
(heigh of infection) |
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convalescent phase
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antibiotics, now white cells protect
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antiphagocitic factors
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phagocytes=wbc
capsules make it hard for white cell to kill bacteria |
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leukocidins
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kills white blood cells
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exoenzymes
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made by cell and released
ex: chimases- dissolve clots, allows microbes to spread, no clots |
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endotoxins
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LPS at gram- bacteria symptoms are non-specefic
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exotoxins
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made and released from bacterial cells, mostly proteins. diseases/symptoms are specefic
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localized infection
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microbe enters body and remains confined to a specific tissue
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systematic
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when an infection spreads to several sites and tissue fluids, usually in the blood stream
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focal infection
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localized infection that spreads
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mixed infection
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multiple infections at the same time
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nosocomial infections
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acquired in a health care setting
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Aseptic techniques
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medicare/medicaid won't pay for catheter uti, surgical sight infection...the hospital pays for it
5-10 billion a year |
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Infection control committee
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tracks infections
training in aseptic techniques implement practices/products |
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Standard precautions for nosocomial infections
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-hand hygiene
-use of personal protective equipment -respiratory hygiene and cough etiquette -safe infection practices -safe handling of potentially contaminated equipment or surfaces |
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Koch's Postulates
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-find evidence of a particular microbe in every case of disease
-isolate the microbe in pure culture -cause the disease in a susceptible host -re-isolate the same organism |
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Lab Safety Levels
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1- regular techniques
2- lab coats, gloves, signs 3- dangerous microbes, specialized clothing, no unsterilized materials can leave lab 4- most dangerous organisms, clothing change and showers required for people entering/leaving |
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Epidemiology
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study of disease in populations
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endemic
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with in the population
ex: valley fever |
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epidemic
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out breaks of disease in populations
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sporadic
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isolated, few cases
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pandemic
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pan=total/all, could affect the entire world
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CDC
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center for disease control and prevention
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WHO
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world health organization
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prevalence
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total number of cases in a population divided by total number of people in population x 100.
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incidence
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measures number of new cases divided by the number of susceptible persons
-per 100,000 |
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point source epidemic
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single source of infection
ex: food poisoning |
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common source
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single source, but over time
ex: contaminated well |
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propagated epidemic
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not one source, but disease passes from person to person
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First line defenses
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always there whether there is a threat or not
ex: tears, urine |
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second line defense
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cellular defenses
ex: phagocytes eat bacteria |
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Acquired defenses
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get it naturally or artificially after exposure to microbe
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naturally acquired
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active- get disease, don't die, won't get it again
passive- protection you get from another individual ex:antibodies made by mom |
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Artificially acquired
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active- vaccination
passive- bitte by snake |
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RBC, WBC, Platelets
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RBC- no nucleus (erythrocytes)
WBC- leucocytes Platelets- fragments |
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development of blood cells and platelets- 1
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start with hematopoietic cell, splits into lymphs or anything but lymphs
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development- 2
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lymphoid stem cell splits into lymphoblasts, lymphocytes are T or B cells, which are agranuloctyes
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development -3
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stem cell for all blood cells except lymphocytes
-red blood cells megakaryocytes -->platelets Granuloctyes: neutrophils, basophils, eosinophils |
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wrights stain
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differential that allows us to determine which cell is which
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WBC's and Dyes
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neutrophils- don't favor one dye, 55%
eosinophils- red dye, 2-3% basophils- all granulocytes, named by how they stain, purple <.5% |
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Agranulocytes
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Monocytes 5%
lymphocytes (t-cells and b-cells)- 20% |
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macophage
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phagocytes, better than monoctyes. found free in blood, fixed in tissues
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mast cell
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specialized tissue cells similar to basophils that trigger local inflammatory reactions and are responsible for many allergic symptoms
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natural killer cells
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related to T cells, except are non specific, wonder body and kill cancer and infected cells
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2nd line defenses
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inflammation, phagocytosis, fever, antimicrobial peptides
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inflammation
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complex series of steps, goes as far as needed.
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cardinal signs
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reactions you an see and feel
rubor- redness calor- heat tumor- swelling dolor- pain |
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Stages of injury
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vascular changes
cellular responses late steps |
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vascular changes
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vasodilation, increase blood flow to are edima, fluid leaks out blood vessels, contains protein
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cellular responses
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involves accumulation of WBC
neutrophils- 24hrs, attracted to the area by bacteria and damaged cells monocytes- 48hrs attracted by chemicals of dead neutrophils |
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Late steps
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a. resolution- healing
b. scarring- connective tissue repair, usually b/c so much injury, no healing. c. phagocytes- activates immune system responses |
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chemotaxis
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movement of white blood cells toward an area of injury/infection
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Phases of phagocytosis
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chemotaxis
attachment/adhesion engulfment phagosome lysosome killing and destruction of bacterial cells release of residual debris |
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attachment/ adhesion
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bacteira adhering to phagocyte PRR's by their PAMPs.
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PAMP
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pathogen associated molecular patterns
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PRR
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pattern recognition receptors
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Fever
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systemic, increase in temp throughout the body
-can kill you b/c it denatures proteins -inhibits bacterial reproduction |
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chemical defenses
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antimicrobial peptides, complement found in blood as a series of inactive proteins --> cascade, forms pores in cell membranes
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interferon
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made by cells infected with viruses
controls spread of a viral infection activates natural killer cells |
