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65 Cards in this Set

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What is minimum inhibitory concentration (MIC)?
• minimum amount of antimicrobial agent needed to inhibit growth of bacteria
• assists in selecting appropriate antimicrobials
What is the difference between bacteriocidal and bacteriostatic antibiotics?
• Cidal: antimicrobials that act by killing the microbes (ex. commonly use bacteriocidal antibiotics to treat bacterial endocarditis)

• Static: antimicrobials that inhibit microbial replication and growth
What is the definition of narrow, extended, and broad spectrum antibiotics?
• Narrow Spectrum: one organism
• Extended Spectrum: various organisms (ex. gram +/-)
• Broad Spectrum (ex. gram +/-, anaerobes, atypicals)
How are most antimicrobials excreted by the body?
by the kidneys
Name 2 drugs that do not require dosage modifications for patients with renal failure.
• erythromycin
• chloramphenicol
What are antimicrobials that require mild dose reductions for patients with renal failure?
• Cephalosporins
• Clindamycin
• PCN
• Rifampin
What are antimicrobials that require major dosage reductions for patients with renal failure?
• aminoglycosides
• Vancomycin
What are antimicrobials that should be avoided in patients with renal failure?
• Nitrofurantin
• Sulfonaides
• tetracylcines
What is a major cause of bacterial resistance?
Beta-Lactamase
What is the most common type of Beta-lactamase enzyme?
penicillinase
What are complications of antimicrobials?
• Hypersensitivity reactions (ex. allergic rxns, photosensivity, or infusion-related rxns)

• Direct Toxicity (on the site where the drug acts)

• Superinfections: caused by inappropriate treatment, non-compliance, or when endogenous bacteria (the good bacteria) is killed
Give an example of a bacteria that appears as diplococci
Neisseria
Give an example of an aerobic gram-positive rod and an anaerobic gram-positive rod
• Aerobic: Listeria
• Anaerobic: Clostridium
List examples of aerobic gram-positive cocci
• Staph. Aureus
• Staph. Epidermis
• Streptococcus
• Strep. Pneumoniae
• MRSA
• Enterococcus
Give examples of anaerobic gram-positive cocci
• peptococcus
• peptostreptococcus (found in the mouth)
List examples of aerobic gram-negative rods
• Acinetobacter
• Citrobacter
• E. Coli
• Enterobacter
• H. Flu
• Proteus
• Pseudomonas
• Salmonella
• Serratia
• Shigella
Give 2 examples of anaerobic gram-negative rods
• Bacteroides Fragilis (common in abdominal/diarrhea related illnesses)
• Bacteroides Melaninogenicus
List examples of gram negative cocci
• Moraxella catarrhalis
• Neisseria gonorrhea
• Neisseria meningitidis
List examples of atypical bacteria
• Chlamydia pneumonia
• Chlamydia trachomatis
• Legionella
• Mycobacterium tuberculosis
• Mycobacterium (MAC)
• Mycoplasma pneumoniae
Give 2 examples of protozoa
• Pneumocysitis Carinii
• Toxoplasma gondi
What is the drug of choice for Pneumocystis carinii?
Bactrim
List examples of fungi
• Asperigillus
• Blastomyces
• Candida
• Cryptococcus
• Histoplasma
Are sulfonamides bacteriocidal or bacteriostatic?
bacteriostatic
What is the MOA of sulfonamides?
inhibits bacterial synthesis of folic acid
What is the role of PABA (p-aminobenzoic acid) in the MOA of sulfonamides?
• PABA is an essential metabolite for the synthesis of folic acid by plants and many microrganisms
• PABA is the target of many sulfonamide drugs
What is the role of folic acid in the body?
• Folic acid is one of the two major single-carbon carriers of the body
• essential for DNA synthesis
Give examples of anatgonists to PABA
• Sulfones (used to treat leprosy): an example of a sulfone is Dapsone which is used in HIV patients who are allergic to Bactrim

• Para-aminosalicylic acid (2nd line antitubercular agent)
Describe the kinetics (absorption, distribution, metabolism, elimination) of sulfonamides
• A - very well absorbed; can be taken orally

• D - crosses blood-brain barrier; passes into all body fluids

• M - metabolized by acetylation (good for the elderly)

• E - acetyllated metabolites are renally filtered (does require dosage adjustment for renal insufficiency)
What are adverse effects of sulfonamides?
• hypersensitivity reactions (Steven Johnson Syndrome)
• agranulocytosis
• hemolytic anemia (tesdt for G6PD deficiency)
• hypoglycemia
• jaundice (in adults)
• kernicterus
What are causes of resistance with sulfonamides?
• altered enzyme (mutations)
• increased drug inactivation
• increased PABA synthesis (due to overuse of sulfonamides)
What is the MOA of Trimethoprim?
• inhibits formation of tetrahydrofolic acid
• inhibits dihydrofolate reductase
What are characteristics of Trimethoprim?
• can be used alone or in combination with sulfas
• bacteriostatic
• bacteria can develop resistance due to the drug's reduced affinity to the enzyme
What are adverse effects of Trimethoprim?
Folic Acid deficiency

* often given folic acid supplementation
What are uses of sulfonamides?
• Burns
• Chlamydia
• Extended spetrum (gram + and gram -)
• Meningococcal meningitis (drug can cross the blood-brain barrier)
• Penicillin-sensitive patients
• Pneumocystis carinii & Toxoplasmosis (for treatment or prophylaxis)
• Pulmonary infection
• Salmonella
• UTI
What is the MOA of penicillins?
• inhibits bacterial wall synthesis by binding and inactivating proteins in the bacterial membrane that regulates cell wall biosynthesis

• PCN binding protein catalyzes the formation of cross links in the peptidoglycan

• PCN binding often causes cell lysis

• inhibits transpeptidase (which contribute to cell wall strength)
Penicillins are ineffective for what types of organisms?
• only effective against organisms that synthesize peptidoglycan cell wall

• not effective againsts viruses, fungi, or mycobacterium
What are the general types of penicllins?
• Natural penicillins
• Antistaphylococcal penicillins
• Extended spectrum penicillins
• Anti-pseudomonal penicillins
Give examples of natural penicillins
• Penicillin G
• Penicillin V
Give examples of the antistaphylococcal penicillins
CONDOM drugs

• C - Cloxacillin
• O - Oxacillin
• N - Nafcillin
• D - Dicloxacillin
• M - Methicillin
Give examples of extended spectrum penicillins
• Ampicillin OR Ampicillin + Sulfbactam (Unasyn)

• Amoxicillin OR Amoxicillin + Clavulanic Acid (Augementin)
Give examples of anti-pseudomonal penicillins
• Carbecillin
• Piperacillin or Pipercillin/Tazobactam (Zosyn)
• Ticarcillin OR Ticarcillin/Clavulanic (Timentin)
Penicillin G is effective against what types of organisms?
• gram +/- cocci
• gram + bacilli
• spirochetes
What are the available formulations of Penicillin G?
PO, IM, or IV
Why is Penicillin G, when administered IM, given with procaine?
Penicillin G is very painful
A single shot Benazthine Penicillin G can be used to treat what?
gonorrhea
The anti-staphylococcal penicillins (CONDOM drugs) are used to treat what type of bacteria?
penicillinase producing bacteria
True/False: Nafcillin should not be used in patients with hepatic failure
• Nafcillin should not be used in patients with liver failure, becuase the drug is metabolized entirely by the liver.

• The correct answer is: True
Which CONDOM drug is the best absorbed PO agent?
Dicloxacillin
Which CONDOM drugs DO NOT require renal dosage adjustment?
• Cloxacillin
• Oxacillin
• Nafcillin
• Dicloxacillin

* Methicillin is excreted by the kidney and require dose adjustment w/ renal failure
Name a side effect of Nafcillin
bone marrow suppresion
Name a side effect of all the penicillins
interstitial nephritis
What structurally distinguishes amoxicillin/ampicillin from Pencillin G?
an amino group added to the Penicillin G ring
What is the spectrum of activity of Ampicillin & Amoxicillin?
• extended spectrum of activity
• Gram +/- (looses some gram + coverage, used more for gram negative bacteria)
What bacterias are treated with Ampicillin or Amoxicillin?
• E. Coli
• Neisseria
• Proteus
• Salmonella
• Shigella

Expanded to gram negative: Klebsiella & Hemophillus
What are the available formulations of Ampicillin?
IV (preferred), but can be taken orally
Name a side effect of Ampicillin
diarrhea
Ampicillin PO is a good agent for the treatment of what?
Salmonella or shigella poisoning
What are available formulations of Amoxicillin?
only PO
What are the most common anti-pseudomonal penicillins used in a hospital?
Pipercillin & Ticarcillin
What organisms do the anti-pseudomonal pencillins cover?
• DOC for non-meningital pseudomonas
• covers gram-negative bacilli and pseudomonas
• less effective aginst gram-positive organisms
What drug should be used with Pipercillin or Ticarcillin for double coverage?
Tobramycin (aminoglycoside)
What are side effects of Carbecillin and Ticarcillin?
• hypokalemia
• hypernatremia (drugs have an increased sodium load)
Carbecillin and Ticarcillin are not good agents for patients with what disease states?
HTN & CHF (because of the increased sodium load)
What are adverse effects of Pencillins?
• C. Dificile
• GI upset
• Nausea/Vomiting
• Rash
• Steven Johnson Syndrome
• Superinfection (overgrowth of fungi)

* allergies are caused by haptens
What is beta-lactamase?
• a common enzyme that hydrolyzes the beta-lactam ring, rendering the drug inactive

• causes resistance to pencillins