AHS 3307 Antimicrobial Pharmacology Study Guide

What is the term for is a chemical substance that has the capacity to kill a microorganism?

Biocidal.

What is the term for a chemical substance that has the capacity to inhibit the growth of a microorganism?

Biostatic.

What are the 4 types of antimicrobials?

- Antibiotics

- Antifungals

- Antivirals

- Antiparasitics

What is the definition of an Antibiotic drug?

A chemical that can kill or harm bacteria, which are prokaryotic cells that have fewer organelles and are smaller than eukaryotic cells.

What are prokaryotic cells?

Bacterial cells.

What are eukaryotic cells?

Animal cells.

What is the Spectrum of Activity?

The types of bacteria against which a particular drug is effective.

What is the goal of antibiotic treatment?

To render the pathogen helpless so that it can be eliminated by the host's immune system without harming the host.

What are Gram positive bacteria?

Bacteria that have a thick, peptidoglycan-rich cell wall that turns purple with staining.

What are Gram negative bacteria?

Bacteria have a thin cell wall that contains less peptidoglycan and takes on a pink stain.

What is an aerobe?

A type of bacteria that requires O2 to survive.

What is an anaerobe?

A type of bacteria that does not need O2 to survive, there are two types, facultative and obligate.

What does time dependent mean in regards to antibiotics?

The antibiotic is required to be at a site for a specific period of time in order to work.

What does concentration dependent mean in regards to antibiotics?

The antibiotic's effectiveness is dependent on the concentration of it at the site.

What is the Agar (Kirby-Bauer) Diffusion test?

A test that is performed in a petri dish where a specific bacteria is grown with little disks of antibiotics, the amount of space between the antibiotic disk and the bacterial growth determines the effectiveness of the antibiotic to that bacteria.

What does resistant mean in regards to the Agar (Kirby-Bauer) Diffusion test?

The antibiotic was not effective.

What does sensitive mean in regards to the Agar (Kirby-Bauer) Diffusion test?

The antibiotic was effective.

What does intermediate mean in regards to the Agar (Kirby-Bauer) Diffusion test?

The antibiotic was partially responsive and can be effective at its max dose.

What does MIC stand for and mean?

Minimum inhibitory concentration, it is the lowest antibiotic concentration that can inhibit the growth of bacteria in a solution.

What is another test that is used to determine the effectiveness of an antibiotic to a specific bacteria?

The Serial dilution test.

What is a breakpoint?

A chosen concentration of antibiotic that is used to determine resistance and sensitivity.

What does in vitro mean?

Outside of the body.

What does in vivo mean?

Inside the body.

What is important to remember about susceptibility testing?

It is done in vitro not in vivo.

What are the 5 antibiotic MOA's?

- Inhibition of cel wall synthesis

- Cell membrane damage

- Inhibition of protein synthesis

- Interfere with metabolism

- Impair nucleic acid activity

How do Cell Wall Agent antibiotics work?

They cause bacterial lysis by getting water into the cell, the cell wall usually keeps the water out through osmosis.

Why are Cell Wall Agent antibiotics advantageous?

Because animal cells do not have a cell wall, the antibiotics will only attack the bacteria because they have cell walls.

Who discovered Penicillins?

Sir Alexander Fleming in 1928.

What are Penicillins only effective against?

Dividing bacteria.

How are Penicillins eliminated?

In the urine, they're good for UTI's because of this!

What bacteria are resistant to Penicillins?

Beta-Lactamase.

What is Penicillin G?

A natural penicillin that is injectable and effective against Staph., Strep., and some Gram + bacilli.

What is Amoxicillin?

A semi-synthetic amino-penicillin that is broader spectrum with activity against Gram - bacteria, it is used more commonly than some other semi-synthetic penicillins.

What is Ampicillin?

A semi-synthetic amino-penicillin that is broader spectrum with activity against Gram - bacteria.

What is Methicillin?

A Beta-lactamase-resistant penicillin that is active against Staph a. Which is a public health concern.

What is Clavulanic acid?

A beta-lactamase inhibitor that causes irreversible binding.

What two penicillins are often administered/used together to optimize treatment?

Clavulanic acid and Amoxicillin, together they are called Clavamox.

What is Sulbactam and what is it used with?

A beta-lactamase inhibitor that is used with Ampicillin as an injectable, together they are called Unasyn.

What are Cephalosporins?

A cell wall agent antibiotics that is semi-synthetic and broader spectrum than penicillins.

What is First Generation Cephalosporin?

The bacteriostatic and bactericidal version of cephalosporin that is effective against most Gram + cocci and some Gram - bacteria.

What is Cefazolin?

A first generation cephalosporin.

What is Cephalexin?

A first generation cephalosporin.

What is Second Generation Cephalosporin?

A version of Cephalosporin that is not used as much in vet med because it is less effective towards Gram + but more against Gram -.

What is Third Generation Cephalosporin?

This generation is less active against Staph a but has more Gram - coverage and is more resistant to Beta-Lactamase destruction.

What is Cefpodoxime?

A third generation cephalosporin that is also known as Simplicef.

What is Ceftiofur?

A third generation cephalosporin.

What is Cefovecin?

A third generation cephalosporin also known as Convenia.

What is Bacitracin?

A polypeptide produced by Bacillus subtilis, it is not susceptible to to Beta-Lactamase but it is highly nephrotoxic, it can only be used topically or ophtho.

What is Vancomycin?

A glycopeptide isolated from soil bacteria that is used for penicillin and cephalosporin resistance.

What are Carbapenems?

A Beta-Lactam that brings to many different bacterial types, it is only used for serious resistant infections and it costs a lot of money which limits usage.

What is Imipenem?

A carbapenem used with cilastatin that is broad spectrum.

What is Meropenem?

A carbapenem cell wall agent antibiotic.

Why are Cell Membrane Antibiotics more difficult than other antibiotics?

Because eukaryotic cells also have a cell membrane, drugs that target the cell membrane also have the potential to attack the patient's own cells.

What do Polymixins do?

They bring bacterial phospholipids to the cell membrane to destroy it.

What is Polymixin B?

A type of polymixin that only attacks Gram - bacteria and is highly nephrotoxic.

How do Protein Synthesis Inhibitor antibiotics work?

They interfere with bacterial mRNA translation, they bind to 30S and 50S subunits to interrupt the synthesis process.

What are Aminoglycosides?

An injectable protein synthesis inhibitor antibiotic that treats Gram - aerobic bacteria. Nephrotoxicity and ototoxicity limit use.

What is Amikacin?

A aminoglycoside.

What is Gentamicin?

A topical spray aminoglycoside that is often combined with a steroid with treatment.

What is Tobramycin?

A aminoglycoside used for ophthalmic infections.

What are Tetracyclines?

Protein synthesis inhibitor drugs that are the product of soil bacteria, are bacteriostatic, can can cause esophageal stricture so they cannot be dry-pilled.

What bacteria can Tetracyclines treat?

Gram +, Gram -, Rickettsial diseases, Aerobic, Anaerobic, Lyme disease, and Leptospirosis.

What Protozoa can Tetracyclines treat?

Toxoplasma.

What Tetracyclines are used to treat Heartworm Disease?

Doxycycline and Minocycline.

What is Oxytetracycline?

A tetracyclines protein synthesis inhibitor that is used in livestock.

What are Phenicols?

Broad spectrum, bacteriostatic protein synthesis inhibitor drugs.

What is Chloramphenicol?

A phenicol protein synthesis inhibitor that is not first line because of the adverse negative effects.

What is Florfenicol?

A synthetic phenicol that is used in food animal medicine.

What are Macrolides?

Protein synthesis inhibitor drugs that attack mainly Gram + aerobes and anaerobes.

What is Erythromycin?

A macrolide that is bactericical or bacteristatic and is usually used in large animal medicine.

What is Tylosin?

A macrolide that treats Gram + and Gram - bacteria, it is often used to treat small animal diarrhea.

What is Azithromycin?

A macrolide that treats Gram + and Gram - bacteria, Lyme disease, Toxoplasma, Bartonella, Bordetella, and Feline URI's.

What are Lincosamides?

Protein synthesis inhibitor drugs that are bacteriostatic or bactericidal and are derived from Streptomyces bacteria.

What is Lincomycin?

A broad spectrum lincosamide that treats Gram + aerobes and anaerobes.

What is Clindamycin?

A broad spectrum lincosamide that treats wounds/abcesses, dental infections, bone infections, anaerobes, and Toxoplasma by binding to 50S subunit.

What are Sulfonamides?

Antibiotics that interfere with metabolism, they can treat Gram + and Gram - aerobic and anaerobic bacteria, and some Protozoa.

How do antibiotics that Interfere with Metabolism work?

They are structurally similar to a chemical precursor of folic acid so they prevent folic acid synthesis which produces negative effects on DNA production and cell division.

What are some of the side effects to Sulfonamides?

- KCS

- Hepatitis

- V/D

- Hemolytic anemia

- Ahaphylaxis

- PU/PD

What are Sulfonamides called when they care combined with another chemical to reduce resistance?

Potentiated Sulfonamides.

What is Trimethoprim/Oremtoprim?

A potentiated sulfonamide that inhibits folic acid production.

What is Sulfamethoxazole?

A sulfonamide that is also known as Trimethoprim Sulfa.

What is Sulfadimethoxine?

A sulfonamide used in both large and small animal medicine, it is also known as Albon.

What is Sulfasalazine?

A sulfonamide used to treat canine colitis.

How do Nucleic Acid Impairing Antibiotics work?

They target DNA activity in bacteria that are different from human cells.

What are Fluoroquinolones?

They are synthetic bactericidal nucleic acid impairing antibiotics that attack Gram + and Gram - bacteria, but not anaerobes. It is concentration-dependent inhibit bacterial DNA gyrase which affects DNA supercoiling and tangles.

What antibiotic should we avoid using in young animals and why?

Fluoroquinolones because they can cause cartilage defects in growing animals.

What antibiotics should we avoid using in cats because it can cause ocular toxicity?

Fluoroquinolones.

What is Enrofloxacin?

A Fluoroquinolone that can be injected or given orally, it is also known as Baytril.

What is Orbifloxacin?

A fluoroquinolone that can be given ophtallicaly or orally.

What is Marbofloxacin?

A fluoroquinolone that is not reported because it causes feline retinal damage.

What is Pradofloxacin?

A fluoroquinolone that cannot be used in dogs because it causes bone marrow suppression.

What are Nitrofurans?

Antibiotics that appear to affect many bacterial enzymes including DNA synthesis, the cell wall, and metabolism. They are broad spectrum but have human carcinogenic potential.

What is Nitrofurantoin?

A nitrofuran that causes bacterial cystitis.

What is Rifampin?

An antibiotic that disrupts RNA synthesis and is broad spectrum.

What is Metronidazole?

An anaerobic antibacterial and antiprotozoal antibiotic that is widely distributed in the body. It can cause neurotoxicity.

Can multiple antibiotics being put together to obtain broad spectrum?

Yes.

What can cause antimicrobial resistance?

Genetic changes such as internal mutation and selective pressure.

What is internal mutation?

Mutations that provide resistance mechanisms get transferred when bacteria reproduce.

What is selective pressure?

It is what occurs with antibiotic administration, the non-resistant bacteria die and the resistant bacteria survive and multiply.

What does it mean to use antimicrobials judiciously?

To use them only when absolutely necessary and when using them, limit the use.