Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
110 Cards in this Set
- Front
- Back
|
How can bacteria acquire resistance?
|
conjugation, transfer resistance, plasmid resistance
|
|
|
What are membrane plugs?
|
A form of antibiotic resistance- mutation results in a protein that blocks access to cell interior
|
|
|
What is ribosomal blockade?
|
A form of antibiotic resistance. A protein is produced by the bacteria that keeps the antibiotic from binding to the ribosome. There is a ribosome decoy
|
|
|
What is synergy in antibiotics?
|
When you combine two bacteriostatic drugs and they become bacteriocidal
|
|
|
When do you use combination drugs?
|
Overwhelming life threatening infections, resistant strains, mixed infections (colonic rupture)
|
|
|
What are some organisms with unpredictable sensitivity?
|
e coli, klebiella, coagulase positive staph.
|
|
|
Which drugs are time-dependent?
|
Bacteriostatic drugs and beta lactams
|
|
|
How should time dependent drugs be administered?
|
Frequent dosing or IV infusion
|
|
|
What are two synergisitc drug combinations?
|
Penicillins or cephalosporins with aminoglycosides
Sulfadiazine and trimethoprim |
|
|
What are two additive combinations?
|
Lincomycin (50S) with aminoglycosides (30S)
Penicillin with erythromycin (reduces erythromycin resistance) |
|
|
What are some antagonistic drug combinations?
|
Static protein synthesis and cidal cell wall synthesis inhibitors: Chlorampenicol and ampicillin or tetracycline and penicillin
Protein synthesis inhibitors that work at same site: Chloramphenicol with lincomycin/erythromycin (50S) Tetracycline with aminoglycosides (30S) |
|
|
When do you use prophylactic antimicrobial therapy?
|
High risk patients: diabetics, immunosuppresed
|
|
|
What is colonization resistance?
|
When normal gut flora suppresses pathogenic organisms by making factors that hurt them
|
|
|
What drugs suppress colonization resistance? (effect normal flora)
|
ampicillin, chloramphenicol, furazolidon, cloxacillin, amoxicillin, tatracyclines
|
|
|
What drugs don't suppress colonization resistance?
|
cephalosporins, aminoglycosides, parenteral penicillins, trimethoprim sulfasoxazole, sulfonamides
|
|
|
What drugs enhance colonization resistance?
|
oral neomycin, polymixin, nalidixic acid
|
|
|
What microbes are common in nosocomial infections?
|
klebsiella, resistant e.coli, serratia, proteus, pseudomonas
|
|
|
Which surgical procedures need prophylactic antimicrobials?
|
respiratory, alimentary, urogenital surgery. Ovariohysterectomy with metritis. Nephrotomy. Tracheal surgery. Gastrotomy, esophagostomy, bowel resection. Long surgeries. Burns. Placement of prostheses. Trauma over 4 hours old.
|
|
|
How should antimicrobials be given for surgery?
|
Intermittent IV boluses of amipicillin are good. Comonly recommended to administer dose at end of surgery because animal is immunosuppressed by anaesthesia and stress. Give no more than 24-72 hours post-surgically.
|
|
|
What drugs should not be given with glucocorticoids?
|
Bacteriostatic drugs. They depend on functioning immune system.
|
|
|
What are the bacteriostatic drugs?
|
tetracycline, chloramphenicol, macrolids, licosamides, sulfanamides, nitrofurans
|
|
|
What are the bacteriocidal drugs?
|
Penicillins, cephalosporins, aminoglycosides, polymixins, trimethoprim/sulfonamide
|
|
|
What is the combined gas law?
|
P1V1 over T1 equals P2V2 over T2
|
|
|
Using the combined gas law, if container A has a volume of 100ml, a pressure of 20 mmHg, and a temperature of 20 degrees, what would be the pressure in container B with a volume of 250 ml at the same temp?
|
p= 8 mmHg
|
|
|
If an anesthetic machine has two vaporizers and one is set to 2% and the other is set to 3%, at sea level the patient attached to this machine would receive 5% inhalant anesthetic. This is an example of which gas law?
|
Dalton's law of partial pressure
|
|
|
Which hypothesis of the mechanism of action of inhalant anaesthetics was supported by the inhibition of firefly luciferase by Franks and Lieb?
|
The protein receptor hypothesis. Receptors in the CNS are responsible for the mechanism of action of inhaled anesthesia. The site of action is a protein, not dependent on lipid.
|
|
|
When activated, the gamma-aminobutyric acid receptor opens an ion channel that allows movement of what ion into the cell resulting in hyperpolarization?
|
Chloride
|
|
|
What are the properties of an ideal anesthetic agent?
|
Non-inflammatory, non-explosive, stable at room temp., stable with soda lime,plastics, rubber, metal, environmentally friendly, pleasant to inhale, low blood:gas solubility, high oil:gas solubility, minimal effects on cardio, respiratory systems, no biotransformation, non-toxic
|
|
|
What influences the alveolar partial pressure of an anesthetic in a patient connected to a rebreathing circuit of an anesthesia machine?
|
Inflow factors:minute ventilation, inspired anesthetic concentration, cardiac output, blood/gas partition
|
|
|
What does the term "splitting ratio" refer to in regards to an anesthetic vaporizer?
|
The inspired anesthetic concentration is determined by the vaporizor setting. Increasing the concentration in the circuit increases the alveolar partial pressure
|
|
|
Which tissue groups reveives the greatest poportion of cardiac output?
|
Vessel rich group- 9% of body mass
|
|
|
Which inhaled anesthetic is classified as a gas?
|
nitrous oxide and xenon
|
|
|
How do you define the surgical MAC?
|
One MAC is the amount (%) at 1 atm (760mm hg) required to prevent gross purposeful movement in 50% of the subjects tested following a 60 second supramaximal stimulus (humans- incision, animals-tail clamp) Surgical MAC is 1.3 to 1.5 times MAC
|
|
|
Sevofleurane MAC in a horse is:
|
2.3
|
|
|
Isoflurane MAC in a cat is:
|
1.6
|
|
|
Which volatile anesthetic directly depresses cardiac activity?
|
Halothan
|
|
|
What are effects of inhalant anesthetics on the respiratory system?
|
depress the chemoreceptor response to CO2- respiratory acidosis
Bronchodilates Interferes with hypoxic pulmonary vasoconstriction so there is V:Q mismatch and decreased arterial PO2 |
|
|
Which anesthetic needs a specialized vaporizer to boil the inhalant anesthetic?
|
desflurane
|
|
|
In which inhaled anesthetic is diffusion hypoxia, transfer to closed space and teratogenic side effects and issue?
|
Nitrous oxide
|
|
|
What do you NOT do if you want to put an animal into deeper anesthesia?
|
Increase minute ventilation, increase oxygen flow rate, increase the anesthetic concentration,( increase cardiac output, increase solubility, increase alveolar to venous anesthetic gradient)
|
|
|
WHat antimicrobials aren't susceptible to beta lactamases?
|
Tetracycline, oxytetracycline
|
|
|
How can a bacteria becoem resistant to a drug without having to come into contact with it?
|
Plasmids
|
|
|
What is clavulanic acid for?
|
It has no antimicrobial action but it inhibits the beta lactamase enzyme made by the bacteria
|
|
|
Which narrow spectrum antimicrobial would work on a skin infection of beta-lactamase producing staph infection?
|
semi-synthetic penicillin omaxacillin-
|
|
|
Are aminoglycosides effective against anaerobes?
|
No
|
|
|
Should you use aminoglycosides to treat an abscess?
|
No
|
|
|
What are seven bacteriostatic drugs?
|
Flunixin, lincosamides, tetracycline, sulfonamides,chloramphenicol,florfenicol, macrolides
|
|
|
How do penicillins work?
|
inhibit peptidoglycan crosslinking in the key synthetic pathway of the synthesis of the gram positive cell wall-BACTERIOCIDAL
|
|
|
How do cephalosporins work?
|
Like penicillin
|
|
|
How are cephalosporins different than penicillin?
|
Broader spectrum- effect gram negatives, too. Better for klebsiella and proteus.
|
|
|
How do polymixins work?
|
Powerfully bind to phospholipids in the cell membrane- BACTERICIDAL
|
|
|
What is the spectrum of polymixins?
|
Gram negative (can bind endotoxin)
|
|
|
How do tetracyclines work?
|
Inhibits transfer RNA binding at 30S ribosomal subunit- BACTERIOSTATIC
|
|
|
How does Chloramphenicol work?
|
Inhibits peptide chain elongation and inhibits function of the 50S subunit- BACTERIOSTATIC
|
|
|
How do macrolides work?
|
Inhibits ribosome synthesis-BACTERIOSTATIC
|
|
|
How do lincosamides work?
|
Inhibits transfer RNA binding at 50S ribosomal subunit- BACTERIOSTATIC
|
|
|
How do aminoglycosides work?
|
irreversible binding and inhibition at 30S ribosomal subunit- BACTERICIDAL
|
|
|
How do quinolones work?
|
Inhibit bacterial DNA gyrase enzyme
|
|
|
How does rifampin work?
|
interferes with RNA synthesis
|
|
|
How do sulfas work?
|
Inhibit folic acid metabolism. Sulfanamides disrupt dihydropteroate synthetase which turns PABA into folate and Trimethoprim disrupts dihydrofolate reductase which turns folate into tetrahydrofolate
|
|
|
How do nitrofurans work?
|
interfere with a variety of cell enzymes
|
|
|
What drugs work against anaerobes?
|
Metronidazole, Penicillin G, Clavulanic acid with amoxicillin, 2nd and 3rd generation cephalosporins
|
|
|
What are the four quadrant choices?
|
quinolone + amoxicillin
clindamycin+aminoglycoside beta lactam + aminoglycoside penicillin + aminoglycoside cephalosporin + aminoglycoside ticarcillin + carbenicillin and amikacin for resistant pseudomonas |
|
|
WHy do penicillins and cephalosporins end up in the urine in such high concentrations?
|
They are weak acids and are moved up the concentration gradient to the urine by the organic acid transport system in the proximal tubules
|
|
|
Which drugs should be given in a time-dependent fashion?
|
Static drugs and beta lactams.
|
|
|
Which drugs should be given in a concentration dependent fashion?
|
aminoglycosides and fluoroquinoones
|
|
|
What do aminoglycosides do to the kidneys?
|
accumulate by pinocytosis in the brush border of proximal tubular cells and cause lysosomal disruption resulting in cell death
|
|
|
What do you give a septicemic foal?
|
Penicillin every 6 hours and amikacin every 24 hours IV
|
|
|
What drugs are banned from use in food animals?
|
Chloramphenicols, metronidazoles, fluroquinolones (except as labelled), sulfanamides (except as labelled)
|
|
|
What are side effects of beta lactams?
|
Hypersensitivity, gut flora effects, suprainfections, blood dyscrasias (cephalosporins)
|
|
|
What drug characteristic is important for CNS infections?
|
Lipophilicity
|
|
|
Is trimethoprim/Sulfadiazine bacteriostatic?
|
No, cidal
|
|
|
What is a beta lactam?
|
4 element ring with an amide linkage
|
|
|
What does metronidazole work on? Where should it not be used?
|
Anaerobes- the urinary tract
|
|
|
What are four essentials for successful antimicrobial use?
|
Drug must come into contact with the bug, drug must be present in high enough concentrations, drug must be present for sufficent period of time, microorganism must be sensitive to drug
|
|
|
What is the difference between third generation cephalosporins and first generation?
|
Third generation generally have a better gram negative and anaerobic spectrum than first generation
|
|
|
What is the problem with rifampin?
|
Bacteria develop resistance fast, and it can cause rapid elimination of other drugs that are metabolized by the liver (increases liver enzymes). Also turns pee and sweat orange
|
|
|
What do you call a tetracycline and an aminoglycoside when given togetehr?
|
an antagonistic antimicrobial pairing
|
|
|
Why aren't fluoroquinolones given to food animals?
|
There is microbial resistance developing to them in human microbes
|
|
|
Why not give penicillin G for an e.coli infection?
|
It only works on gram positives
|
|
|
How do microbes develop resistance to trimethoprim?
|
By producing dihydrofolate enzymes with an altered shape so the drug can't bind to it
|
|
|
How many times the MIC must the peak concentration of an aminoglycoside be?
|
8-10 times
|
|
|
How is procaine used?
|
TO ALLOW LESS FREQUENT IM administration of penicillin G
|
|
|
Where don't aminoglycosides work?
|
In anaerobic environments, acidic environments and where there is a lot of pus
|
|
|
What converts to ampicillin in the gut?
|
hetacillin
|
|
|
Where is cloxacillin used?
|
intramammary
|
|
|
What does carbenicillin work on?
|
proteus and pseudomonas- only parenteral
|
|
|
What do piperacillin and ticarcillin work on?
|
pseudomonas, enterobacter, klebsiella
|
|
|
How is bacitracin used?
|
Mainly topical for gram positives.
|
|
|
What is the spectrum of polymyxins?
|
Gram negative
|
|
|
What is the toxicity of polymyxins?
|
nephrotoxic, neurotoxic, local allergies
|
|
|
What is tetracycline effective against?
|
Gram positive, gram negative, mycoplasma, rickettsia, chlamydia, protozoa
|
|
|
WHat has outstanding lipid solubility for brain and eye infections?
|
Chloramphenicol (but requires activation in liver)
|
|
|
What is the spectrum of lincosamindes?
|
Gram positive cocci. Esp. penicillinase producing staph
|
|
|
What is amikacin used for?
|
Gentamicin resistant gram negative infections
|
|
|
What is cuprimixin for?
|
gram positives, gram negatives, ringworm, actinomyces, yeast
|
|
|
What are quinolones synergistic with?
|
aminoglycosides
|
|
|
What are quinolones good for? WHy?
|
Resistant UTIs. Effective against pseudomonas, klebsiella, proteus. (Only gram negatives) High concentrations in bile and urine.
|
|
|
What antagonizes quinolones?
|
chloramphenicol and rifampin
|
|
|
What is the toxicity of quinolones?
|
Cartilage damage, GI and hepatic problems
|
|
|
What is nalidixic acid?
|
The parent compound of quinolones- too neurotoxic to use in dogs an dcats. Newer quinolones like ciprofloxacin is better.
|
|
|
What does rifampin work on?
|
resistant staph, some gram negatives, tuberculosis, chlamydias, some viruses
|
|
|
What are azalides effective against?
|
gram positive aerobes and anaerobes
|
|
|
What are trimethoprim sulfas effective against?
|
mainly gram positives and protozoas, plus e.coli, strep, salmonella, pasteurella, shigella, nocardia, actinomyces
|
|
|
What do potentiated sulfas not work on?
|
Leptospira, pseudomonas
|
|
|
What was the durham humphrey amendment?
|
Says you can only buy some things with a prescription
|
|
|
What did the 1958 food animal amendment do?
|
Regulated food animal drugs as additives, required proof of food safety
|
|
|
What was the kefauver harris amendment?
|
Required proof of efficacy and AE reporting (?)
|
|
|
What was the animal medicinal drug use clarification act?
|
determined extra label uses, compounding, flex labelling
|
|
|
Does the CVM dept of the FDA regulate biologicals, pesticides or topical parasiticides?
|
No, the USDA and EPA does
|
