• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/107

Click to flip

107 Cards in this Set

  • Front
  • Back
chemotherapeutic agents
chemicals that interfere directly with the proliferation of microorganisms, at concentrations that are tolerated by the host
bacteriostatic drug
inhibition of growth reversed when the drug removed
immune system must still kill the microbe
bactericidal drug
exerts irreversible, lethal effect
Dead bugs don't mutate
won't develop resistance
antiseptic
opposes sepsis or putrefaction
applied to living tissues
disinfectant
prevents infection
applied to inanimate objects
sanitization
reduces numbers of bacteria to acceptable standards
sterilization
complete destruction of all forms of life
what type of control method for microorganisms will kill endospores?
Autoclave
will endospores survive pasteurization?
YES
it disinfects and kills milk-borne pathogens and vegetable forms but not endospores
does radiation have good or bad penetrating power for killing microbes?
Poor penetrating power
works well on surfaces such as desk and hoods
True or False
antibiotics are filter sterilized
True
Provide examples of strong oxidizing agents
Halogens
Iodine
Chlorine
Bromine
Fluoride
provide examples of acylating agents
Formaldehyde: toxins, surfaces
Glutaraldehyde: less toxic than formalin
Ethylene oxide: heat sensitive objects
what is the most effective concentration of alcohol on microbes (not humans)?
70-90% Isopropyl alcohol
why does hydrogen peroxide kill anaerobes?
bacteria do not have catalase to break it down
what are zinc salts used for?
topical and antifugal treatment
what is the site of lysozyme attack for antibiotics in a gram positive cell wall?
NAG-NAM linkage in b-1,4
what is a NAM that is present in the cell wall of a Gram + bacteria?
Muramic acid which is a NAG with lactic acid esterified in C3
how is a cell wall produced by a Gram + bacteria?
Transglycolase
Transpeptidase
Carboxylase
Racemase
FEM proteins
what is responsible for the cross linking in the cell wall of gram + bacteria
Pentaglycine or tetra/pentapeptide
what is the role of D-amino acid racemase in the cross linking formation?
to recycle the D-Ala after the petapeptide and tetrapeptide have been linked
how does cycloserine play a role as an antimicrobial?
inhibits reactions involved in incorporation of alanine into cell wall precursor
what is the function of the bacitracin antimicrobial?
prevents dephosphorylation of phospholipid carrier which prevents regeneration of carrier necessary for synthesis of the cell wall to continue
what is the function of the glycopeptides as a antimicrobial?
bind to terminal end of D-ala-D-ala residues and prevents incorporation of subunit into growing peptidoglycan
how do beta-lactams inhibits the cell wall synthesis of bacteria?
bind to and inhibit enzymes which catalyze the link which attaches the new wall unit to the growing peptidoglycan
what are the different mechanisms of action that an antimicrobial can have?
inhibit protein synthesis
inhibit DNA or RNA synthesis
Inhibit folate synthesis
Inhibit cell wall synthesis
what are the properties of an ideal chemotherapeutic agent?
antimicrobial properties:
selectivity for microbial rather than mammalian targets
Cidal activity
slow emergence of resistance
Narrow spectrum of activity
what are the pharmcological properties of an ideal chemotherapeutic agent?
Non-toxic to the host
Long plasma half life
Good tissue distribution including CSF
Low plasma protein binding
Oral and parenteral dosing forms
No interference with other drugs
what is the mechanism of action for BETA LACTAMS?
this antibiotic with 4-membrane Beta lactam ring sterically resembles mucopeptide biosynthesis intermediate
1. acts by binding to enzymes involved in final process of cell wall synthesis -inhibits polymerization and attachment of new peptidoglycan to cell wall
2. Penicillin binding proteins
what is the mechanism of action for Penicillin family of antimicrobials?
steric similarities of penicillin and D-ala-D-ala end of peptidoglycan
1. blocks cross linking of pentaglycyl bridge
2. leads to weakend mucopeptide and cellular lysis
spheroblast > protoplast > cytolysis
3. requires growing cells in order to be expressed
DONT USE WITH BACTERIOSTATIC DRUGS
4.
Is penicillin more effective in gram + or gram - bacteria?
generally more effective in gram + bacteria
True or False
Penicillins are bacteriacidal
True
they kill the bacteria
what is the penicillin binding protein?
transpeptidases
what must the beta-lactam penicillin do to be effective
1. penetrate the cell layers
2. keep its beta-lactam ring intact
3. Bind to the transpeptidase
how do gram negative bacteria defend themselves from penecillin?
altering their porins
how do gram negative and gram positive bacteria defend themselves against penecillin?
Beta lactamase enzymes that cleave the C-N bond in the beta-lactame ring
Alter structure of transpeptidase
True or False
with each new generation of cephalosporins the drugs are able to kill an increasing spectrum of gram negative bacteria
True
Do patients that have an allergy to penicillin have an allergy to 3rd generation cephalosporins?
10% of patients do
Same allergic reaction occurs
IgE mediated reaction or more common a rash appearing weeks later
what are 3rd generation cephalosporins used to treat?
multi-drug resistant aerobic gram negative organisms that cause hospital acquired pneumonia, meningitis, sepsis, or urinary tract infection
what are Monobactams used to treat?
narrow spectrum limited to aerobic gram negative bacteria
may be combined with other antibiotics
what is the mechanism of action for penicillin, cephalosporin, monobactams, carbopenems, and beta-lactamase inhibitors?
blockage of cross linking of the pentaglycyl bridge in the cell envelope
what are clavulanate and sulbactam used for?
these drugs must be used in combination with other drugs.
they are beta lactams such as methicillin
1. used in with penicllin to protect beta lactamase and keep effective antibiotic
why is staphylococcus aureus resistant to penicillin?
it produces a penicillinase
what is the point in giving a beta latamase inhibitor with a penicillin?
these enzymes are inhibitors of beta lactamase and are given in combination with penicllins to create a beta lactamase resistant combination
what is the mechanism of action of Vancomycin?
blocks cross linking of peptidoglycan pentapeptides by binding to D-ala-Dala end
what is Vancomycin used to treat infections of?
used to treat infections with methicillin and cephalosporin resistant Staphylcoccus (MRSA)
what is the drug of last resort for resistant strains of bacteria?
Vancomyocin and Teicoplanin
why does the treatment with vancomyocin require hospitalization?
painful and toxic
kidney failure is possible
treatment must be long term for it to be effective
what type of bacterial infection is Vancomyocin used to treat?
gram positive cocci resistant strains such as MRSA
why are agents affecting the cell membrane permeability such as polymyxins generally more toxic to humans?
due to nonspecific mechanism of action
they are used to treat Gram Negatives
what is the mechanism of action for Polymyxin B?
passes through the outer cell membrane of gram negatives dissolves the cytoplasmic membrane (phospholipids)
what is the mechanism of action of Polymyxin B?
passes through the outer membrane of gram negatives dissolves cytoplasmic membrane
where does polymyxin b pass through? what could this be a concern for?
passe through the kidneys, not the CSF
patients with parenteral treatment must be in the hospital due to renal involvement
what type of infection is Polymyxin B used to treat?
Pseudomonas, and other gram negative bacteria nonrefractive to other drugs
how many antimicrobials are there that inhibit protein synthesis?
8
what are the 8 antimicrobials that inhibit protein synthesis?
(CLeAn TOMS)
C: Chloramphenicol & Clindamycin
L: Lincomyocin
e
A: Aminoglycosides
n
T: tetracylcines
O: oxazolidinones
M: macrolides
S: streptogramins
which drugs bind to the 50S ribosome to inhibit protein synthesis?
Chloramphenicol
Clindamycin
Lincomyocin
Steptogramins
Which drugs bind to the 30S ribosome to inhibit protein synthesis?
Aminoglycosides
Tetracyclines
what is the mechanism of action of macrolids?
blocks protein synthesis
what is the mechanism of action for Oxazolidinsones?
inhibits the A & P sites
what is the mechanism of action for Tetracylcine?
bind to 30S ribosome
blocks tRNA access prevents translation
when tetracycline is administered to a patient is the antimicrobial going to kill the bacteria or is the eradication of the microbial dependent on the immune system?
Tetracycline is bacteriostatic
it will keep the bacteria from growing and multiplying
Eradication is dependent on the immune system
what is a macrolide?
an antimicrobial that has a basic structure of Erythromyocin but modified to from the macrolides such as Azithromyocin and Clarithromycin
Azithromyocin and Clarithromyocin are examples of what type of antimicrobial?
Macrolides
what do macrolides bind to in order to stop protein synthesis?
50S ribosomes subunit blocking macromolecule synthesis
what type of bacteria is macrolides useful against?
Gram positive >>>> Gram Negative
Intracellular bacteria: Chlamydia Mycoplasma
Is Spectinomycoin bacteriocidal or bacteriostatic?
bacteriacidal
What is used specifically for the treatment of gonorrhea?
Spectinomycin
Is Spectinomyocin effective for treatment of syhphillis?
NO
what is the mechanism of action for Spectinomycin?
binds to 30S ribosome subunit
what is the mechanism of action for Clindamycin/Lincomycin?
blocks protein synthesis bpy binding to 50S ribosome subunit
what was the first commercially synthesized antibiotic?
Chloramphenicol
what is the mechanism of action of Chloramphenicol?
binds to 50S subunit to prevent translation by blocking protein bond formation
this also effects mammalian ribosomes
What is Chloramphenicol used to treat?
SEVERE DISEASES
because it can cause hypersenstivity, acts on mammalian cells
and 1/40,000 causes bone marrow aplasia
Give examples of an Aminoglycodside antibiotic?
Gentamicin
Streptomycin
Tobramycin
what is the mechanism of action for Streptomycin?
bind to 30S ribosome subunit to give misreading leading to missense or nonsense proteins
what is the mechanism of action for Oxazolidinone?
inhibits A and P sites in protein synthesis
What would you use Oxazolidinone to treat?
used almost exclusively against resistant gram POSITIVE cocci such as VRE to prevent development of resistance
what is the mechanism of action of Streptogramins?
binds to 50S ribosome subunit
Is Clindamycin affected against anaerobic microbes?
YES
What would a surgeon use as an antibiotic for a penetrating would such as a knife or bullet wound?
Clindamycin along with an amingoglycoside
why is clindamyocin with an aminoglycoside used to treat a penetrating would to the abdomen?
when the GI tract is perforated it releases its contents of gram negative and anaerobic bugs into the peritoneal cavity. The aminoglycosides take care of the aerobic gram negatives and clindamycin takes care of the anaerobes
what is used to treat pseudomembranous colitis caused by Clostridium difficile?
Vancomyocin and Metronidazole
what are some side effects of streptomycin?
CN VIII toxicity which can cause vertigo and hearing loss
hearing loss is usually irreversible
Can Spectinomycin be used to treat Gohnorrheoea that is resistant to penicillin and tetracylcine?
YES
caused by Nisseria gonorrheoeae
what is the mechanism of action of a sulfonamide?
Bacteriostatic
competitive antagonist of PABA which leads to folic acid
what step in folic acid synthesis do sulfonamides interfere?
it acts as the enzyme would to convert PABA into dihydropteroc acid
instead with a sulfonamide present the bacteria runs out of folic acid
what type of drug is Trimethoprim?
sulfa-like drug used alone or with sulfamethoxazole
what is the mechanism of action of Trimethoprim?
highly selective for dihydrofolate reductase of microbes
It inhibits folic acid synthesis
used in treatment of urinary infection
what would be a common use for Trimethoprim?
urinary infection
what is the classification of a sulfonamide?
antimetabolite
what drugs are inhibitors of RNA/DNA synthesis?
Quinolone
Rifampin
Rifabutin
Metronidazole
describe the mechanism of action of Quinolone.
binds alpha subunit of DNA gyrase
describe the mechanism of action of Rifampin/Rifabutin
prevents transcription by binding DNA dependent RNA polymerase
describe the mechanism of action of Metronidazole
disrupts bacteria DNA
Is a cytotoxic compound
which antibiotic binds the alpha subunit of DNA gyrase?
Quinoline
what antibiotic prevents transcription by binding DNA dependent RNA polymerase
Rifampin/Rifabutin
what antibiotic disrupts bacteria DNA?
Metronidazole
what type of infection would you prescribe rifampin for?
Mycobacterium
meningococcus
what type of bacteria does Quinolones act on?
gram positive and gram negative
block DNA gyrase which is essential for DNA replication and repair
what type of infection would you prescribe Metronidazole?
anaerobic infections
GI abscesses f
what antibiotic can be used as antibuse for alcoholics?
Metronidazole
what is found in Quinolone that makes it difficult for microbes to develop resistance?
Ciproflaxin is an example of a Quinolone
Fluorine is present which makes metabolism in the microbe difficult
what antibiotics prevent polypeptide elongation at the 50S ribosome?
Macrolide
Clindamycin
Steptogramins
what antibiotic prevents initiation of protein synthesis at 50S ribosome?
Oxazolidinone
What antibiotic prevents polypeptide elongation at the 30S ribosome?
Tetracycline
what antibiotic produces premature release of aberrant peptide chains from 30S ribosome?
Amingoglycoside