CPA #16 Questions Flashcards
Define: diffusion susceptibility test
aka Kirby-Bauer tests
- inoculate Petri dish with standard amount of pathogen
- small circles of paper containing the standard drug concentration are applied
- the bacteria grow a “lawn” everywhere that the drug is not
- examine plates for the zone of inhibition
- a larger zone of inhibition = more effective drug
Define: zone of inhibition
clear area where bacteria do not grow
what are the 3 classifications of pathogens
- susceptible
- intermediate
- resistant
Define: MIC Test and what 2 tests are used
a way to express a drugs potency as a minimum inhibitory concentration; aka the smallest amount of the drug that will inhibit bacterial growth
determined via:
1. broth dilution test
2. Etest
define: Broth Dilution Test (MIC)
bacteria is added to a bacterial agent in a tube or well and observed for turbidity; turbidity indicates bacterial growth, lack of turbidity indicates inhibition of growth
Define: Etest (MIC)
plastic strip containing a gradient (various levels) of microbial agent is placed onto a Petri dish; after incubation a larger inhibition zone will be noted toward the higher concentration of microbial agent, the zone will get smaller as the concentration decreases
Define: MCB Test
minimal bacterial concentration test; amount of drug required to kill the microbe
Identify 3 routes of drug administration for internal infections
- orally
- intramuscular
- intravenous
pros of oral drug administration
simplest; self-administered
cons of oral drug administration
lower drug concentration; d/t being self-administered, people do not always follow prescribed timeframes
pros of IM drug administration
allows drug to slowly diffuse into blood vessels
cons of IM drug administration
concentration is never as high was IV; damage to liver and kidneys
pros of IV drug administration
directly into bloodstream; high initial concentration
cons of IV drug administration
needs continuously administered; damage to liver and kidneys
what are the 3 main antimicrobial drug safety and side effects
Toxicity, allergies, disruption of normal microbiota
define: toxicity
adverse reactions to drugs that may cause damage to kidneys, liver, or nerves, and fetus (if applicable); therapeutic window
define: therapeutic window/range
range of concentrations of the drug that are effective without being excessively toxic
define: allergies
some drugs trigger immune responses; most severe and rare is anaphylactic shock
define: disruption of normal microbiota
may allow opportunistic pathogens to proliferate as secondary infections
list 7 ways that microorganisms can be resistant to antimicrobial drugs
- produce an enzyme that destroys/deactivates drug
- may slow/prevent entry of drug
- alter the target of drug so drug cannot attach effectively
- may alter metabolic chemistry
- pump antimicrobial out of cell before drug can act
- create biofilms
- some strains of mycobacterium tuberculosis can resist fluoroquinolone drugs (create decoy)
define: multiple drug resistant pathogens
aka superbugs; resistant to 3 or more different types of antimicrobials; concerning because caregivers must be able to take care of patients without effective drugs without infecting themselves or spreading it to others
Define: cross resistance
when resistance to one antimicrobial confers resistance to another similar antimicrobial
four ways that we can reduce microbial resistance
- maintain high enough concentration of drug for a long enough time (take full prescription)
- use multiple drugs in combination (synergism)
- limit the use of the drugs to a necessary basis
- using semi-synthetic drugs by adding different chains to original molecule
define: synergism
when use of one drug enhances the effects of another drug
what are the 3 things a pathogen must do to be able to cause disease?
- gain access either by penetrating the surface of the skin or enter through another portal of entry
- attach itself to host cells
- evade the bodies defensive mechanisms long enough to produce harmful changes
define: innate immunity
present at birth; aka natural or native immunity; always active, nonspecific, and rapid - works against a wide variety of pathogens
define: adaptive immunity
lymphocytes; third line of defense; respond against unique species and strains of pathogens and alter the body’s defense; act more effectively upon subsequent infection
what are the main components of the first line of defense
innate immunity
1. skin
2. mucous membranes (respiratory, digestive, urinary, reproductive systems)
what are the 2 layers of skin
- epidermis
- dermis (hair follicles, glands, and nerve endings)
what are the 3 major ways the outer layer of skin protects against infection?
- barrier
- continual replacement of dead skin cells, removing pathogens
- dendritic cells
define: dendritic cells
defensive cells; slender, fingerlike processes extend among the surrounding cells; devour cells non-specifically (phagocytosis) and play role in adaptive immunity
how does the inner layer of skin protect against infection
- collagen: gives skin strength and pliability to prevent punctures
- dermal cells: secrete antimicrobial peptides
- sweat glands: secrete perspiration (contain salt, antimicrobial peptides, and enzymes)
where are mucous membranes found?
- respiratory
- urinary
- digestive
- reproductive
how do mucous membranes defend against infection
non-specific; goblet cells, ciliary escalator
define: goblet cells
secrete an extremely sticky mucus that acts as a barrier trapping bacteria
define: ciliary escalator
cilia propel mucus and trapped particles up and away from the lungs
define: lacrimal apparatus
group of structures that produce and drain away tears
how does that lacrimal apparatus protect from infection
secrete tears that wash over the eyes, removing pathogens and secrete lysozymes (destroy bacteria); the greater the irritation, the greater production
define: microbiome
normal microbes on body that play a role in protecting the body by competing with potential pathogens (aka competitive inhibition)
how does the normal microbiota defend against infection
- consume nutrients
- change pH
- block pathogens from attaching
- stimulate body’s second line of defense
- generate antimicrobial compounds
- improve health through production of vitamins (blood clotting, vitamin K)
define: antimicrobial peptides
aka defensins; act against microorganisms; secreted onto skin, found in mucous membranes, found in neutrophils
what are the main components of the second line of defense?
plasma + blood cells
what are formed elements?
cells and cell fragments suspended in plasma
what is the process of blood formation
hemopoiesis
where are formed elements made
bone marrow, blood stem cell
what are the three types of formed elements
erythrocytes, platelets, and leukocytes
which of the three formed elements are aka red blood cells
erythrocytes
which of the three formed elements are aka white blood cells
leukocytes
which of the three formed elements are pieces of megakaryocytes
platelets
what are the three types of granulocytes
basophil, neutrophil, eosinophil
what are the two types of agranulocytes
monocytes, lymphocytes
which leukocytes can perform phagocytosis
neutrophil, eosinophil, monocyte
what is the difference between granulocytes and agranulocytes
granulocytes have large visible granules
what is diapedesis
exiting the blood cells to invade microbes in tissues by squeezing between cells lining the blood capillaries (basophils, neutrophils and eosinophils can do this)
why is diapedesis important
they can phagocytize or release inflammatory chemicals to help fight infection
how do monocytes leave the blood
diapedesis
what do monocytes mature into?
macrophages
what is a differential WBC count
the proportions of WBC
increase in percentage of eosinophils means what?
allergies, parasitic worms
increase in leukocytes/ neutrophils means what?
bacterial infections
increase in lymphocytes
viral infections
increase in certain types of leukocyte number over normal can indicate what?
cancer
decrease in certain types of leukocyte number below normal can indicate what?
immunodeficiency
