Pharm test 2

Bactericidal

kills bacteria

Bacteriostatic

• Prevents replication of bacteria and slows the growth

• Depending on the immune system to kill off the rest of the bacteria and allows the body to eliminate the infection.

Can what the drug does to a bacteria change depending on the type of bacteria and the dosage the drug is given at

• yes

• Some drugs are -cidal for some bacteria and static for others

• drugs may be -static at normal doses and -cidal at nigher doses

Drugs that counteract infection work in 2 ways

• Some have the capacity to kill the organism by attacking a part of it that the patients doesn’t have

• some have the ability to inhibit the growth of the organism by injuring it and relying on the patients immune system to kill the organism

Antimicrobials types

Antibiotics antifungals, antivirals, and antiparasitic.

antibiotics

chemicals that work only on bacteria

spectrum of action

• refers to the range of bacteria that a specific antibiotic can effectively target, which can be narrow (limited to a few types) or broad (effective against many types).

• the range on which the agent is effective is based on the gram stain

antibiotics Broad spectrum

act on both gram positive and gram negative bacteria

antibiotics narrow spectrum

act on either gram positive or gram negative bacteria

should you use a broad spectrum antibiotic if a narrow will work

no you should not this will create antibiotic resistance, potentially harming the patient and increasing treatment challenges.

bactericidal antibiotics

• Antibiotics that can kill the bacteria that they act against

• Does this by damaging this key bacterial structures of actively dividing bacteria during development Or it will disrupt cell membranes or protein synthesis of the bacteria and cause bacterial death in existing and multiplying bacteria

Bacteriostatic antibiotics

• Antibiotics that inhibit the growth or replication of bacteria

• Its method is to prevent the division of bacteria

• The goal of both of these methods is to attach bacteria and not hurt the animal that is being treated

What happens after the antibiotic for an infection has been chosen

• The antibiotic is placed into tubes at various concentrations and then the bacteria is put into the tubes as well. Then the lowest concentration of antibiotic that has no visible bacterial growth is the minimum inhibitory concentration

What is the minimum inhibitory concentration

The lowest concentration of the antibiotic that has no viable bacterial growth

What are the 5 main ways antibiotics work

1. Inhibiting cell wall synthesis ( only when bacteria is growing and dividing) therefore allowing the cell to fill with water ( antibiotic punches holes into the cell walls)

2. Damage the cell membrane, altering its permeability

3. Inhibition of protein synthesis at the ribosomes ( can’t go through growth)

4. Interference with metabolism by blocking the action of enzymes of binding to compounds needed by the bacteria

5. Impairment of the production of the production of nuclei acids making them unable to divide or function

How is antibiotic resistance created

• Instead of being inhibited or destroyed by a particular antibiotic, the bacteria survive and counter to multiply

• Resistance occurs when bacteria change in a way that reduces or eliminated the effectiveness of the antibiotic

• This can happen when the drug is not used properly as in given for the proper length of time or not given at the proper dosage.

Mutation of bacteria

• The bacteria acquires genes that code for resistance

• They can create pumps to pump them out

Antibiotic residues

The presence of a chemical or its metabolites in animal tissues or food products

Why is antibiotic residues in food anaimls an issue

• It can cause allergic reactions

• They can produce resistant bacteria

• Cooking or pasteurization does not eliminate residues

• Withdrawal times are set to help eliminate antibiotic in food products

Classes of antibiotics ( mechanisms of actions)

• Cell wall agents

• Cell membrane agents

• Protein synthesis agents

• Antimetabolites

• Nucleic acid agents

How to avoid the development of resistant infections

• Do not use antimicrobials for mild infections, they should only be used for severe infections

• Usage needs to be based on diagnosis

• Broad spectrum should not be used if a narrow spectrum drug will work

• Need to make sure the owner gives the full course of antibiotics ( full therapeutic dose)

• Use topical or local antibiotics if able to

What type of infection should antimicrobails only be used for

Should only be used for severe infections

What test should be used when prescribing an antibiotic

• A sensitivity test should be used to determine antibiotic used ( culture and sensitivity)

• This would be Kirby-Bauer disk diffusion assays

• This helps determine sensitive and potential effectiveness of a particular antibiotic to a particular infection

How do antimicrobials work

• it needs a microorganisms that is susceptible to it’s effects

• The microbial drug must reach the target tissue in high enough concentrations to fight the infection

Pros of antimicrobials

• Low cost

• Ease of use

• Minimal side effects

How is an antibiotic chosen

• Need to consider the most likely microorganisms that is involved

• Use target therapy charts and books to determine if the antibiotic will reach tissue/organ

• Consider the age health status and pregnancy status

• Consider the drug itself ( cost, toxicities and ease of administration)

• Consider side affects

• Consider drug elimination routes

Sensitivity

Organisms succumbs to the drug

Resistancy

Organism not susceptible to the drug

How does resistance occurs

• Through mutation or adaptation by the microbes

• Microorganism develops tougher cell walls or characteristic is over time to circumvent the antimicrobials drug

iatrogenic resistance ( human cause this type of resistance)

• Stop the antibiotics too soon

• Over use of antibiotics

• Subtherapeutic dosing

• Overuse of broad spectrum antibiotics

How to avoid resistance

• Use a drug with minimal history of resistance

• Rotate antibiotics if on longer term therapy

• Use a narrow spectrum drug whenever possible

• Never use prophylactic drug use

• Use full dose, need to avoid sub-therapeutic dosing

• Use culture and sensitivity to find the best antibiotic for the job

What are adverse effects of antibiotics

• Certain antibiotics will kill off normal gut flora that is essential for normal function Gi tract. When this occurs there’s an overgrowth of pathogenic bacteria and yeast.

• That over growth will lead to severe enteritis in pigs, horses, rabbits, hamsters and guinea pigs In these patients the wrong antibiotic will be fatal

• It can cause a fatal diarrhea And anaphylaxis reactions

• Will cause toxicity to these organs ototoxic, nephrotoxic, hepatotoxic, GI ulceration, bone marrow, suppression and teratogenic.

What happens when the normal gut flora is killed off in the Gi tract

An overgrowth of pathogenic bacteria and yeast will occur leading to severe enteritis

What animals are prone to severe enteritis caused by antibiotics

Pigs, horses, rabbits, hamsters and guinea pigs

What are the five mechanisms of antibiotic drug action

• Interferes with bacterial wall formation ( will rupture the cell wall) Interfere with cell wall synthesis to cause weakness

  • Needs rapid cell growth/replication rate

  • Penicillin family

• Interferes with bacterial cell membrane ( leaks)

  • Changes permeability of cell membrane and allows vital substance to leak

  • Not common in vet med ( polymyxin B)

• Interfere with protein synthesis by attaching to mRNA to stop dividing ( death or leak)

  • Attaches to the ribosomes

  • Doesn’t need cell growth to work

  • Aminoglycosides

• Interferes with critical enzymes ( bind to them)

  • Inhibits enzymatic activity

• Interfere with RNA and DNA production

  • Damage RNA and DNA production

  • Damage RNA or DNA of microbe

  • Can’t replicate

Which antibiotics are not allowed to be used in food animals

• Aminoglycosides

• Fluroquinolones

• Chloramphenicol

• Sulfonamides

Antibiotics that are cell wall agents

• Penicillin

• cephalosporins

• bacitracin

• Vancomycin

• Carbapenems

• Monopenems

Protein synthesis agents ( binds and affects transcription/ translation)

• Aminoglycosides

• Tetracyclines

• Chloramphenicol

• Lincosamides

• Marcolides

• Florfenicol

What antibiotics inhibit DNA or RNA synthesis

• Fluroquinolones

• (Inhibits bacterial enzymes DNA-gyrase; interferes with coiling of bacterial DNA)

Penicillins the 1st true antibiotic

• Suffix -cillin

• Safest, but has lots of resistancy has developed

• Many are suspension ( may need to be shaken)

• Made from penicillium mold

• Is a cell wall inhibited, punches holes in cell walls

The suffix for Penicillins

Cillin

Pharmacokinetics of penicillins

• Oral absorption in small intestines ( some absorption in stomach)

• Should be given on empty stomach ( except Amoxicillin) as presence of food affects bioavailability of drug

• Injections are rapidly absorbed an distributed

• Excreted through the kidneys

• Crosses the mammary gland and placenta, but not the Blood brain barrier

• Times vary for WD times in food animals

How are Penicillins are excreted by what organ

Though the kidneys

Pharmacodynamics of Penicillins

• They have a betalactam ring that binds irreversibly to proteins involved in cell wall synthesis. This leads to cell death.

• They are effective against most gram + bacteria (some Gram - bacteria)

• Not effective against beta lactamase producing bacteria ( must be potentiate)

• Binds to proteins

What does penicillins have that help them kill bacteria

They have a betalactam ring that binds irreversibly to proteins involved in cell wall synthesis. Which leads to cell death.

Beta-lactamase

• Is produced by beta-lactamase which are enzymes that inactivets antibiotics

• beta-Lactamase breaks down beta lactase ring tha is present in penicillin

• when the beta-lactase ring is destroyed than the antibiotic is useless

• Beta-lactamase converts penicillin into the inactive form.

What does beta-lactamase do to antibiotics

• It breaks down the betalactam ring that is present in penicillin

• It will convert penicillin into the inactive form

What is penicillin clinically used for

Used for treating sensitive bacterial infections ( first round drug in Urinary tract infections)

Types of penicillin

• amoxicillin ( tablets, drops)

• Ampicilin ( injectable, capsules)

• Carbenicillin ( antipseudomonal)

• Cloxacillin ( mastitis)

• dicloxacillin

• Penicillin G ( im or SQ) always injectable narrow

• Ticarcillin

Potentiated Penicilins

• Drug that is chemically combined with another drug to enhance the effects of both drugs

• Addition of the drug to deal with bacteria that produces beta-lactamase. It acts to inhibit the action of beta lactamase

• example: amoxicillin + Clavulanic acid = Clavamox

Clavulanic acid

• Is a betalactamase inhibitor

• Binds to betalactamase produced by bacteria to protect betalactam ring of amoxicillin

Amoxicillin and Clavulanate Potassium

• clavulanate is a beta-lacatamase inhibitor

• Reduces resistancy of penicillin resistant infections

• Used for

  • Skin infections, URi in cats, wounds, UTI, Liver infections

  • Trade names: Clavamox generic: Augmentin

  • Adverse effects: V/d in some patients

adverse effects of penicillins

• allergic reactions: hives, respiratory distress, rashes, fever, facial swelling

• Severe anaphylactic reaction( usually from injections)

Cephalosporins

• Penicilins + Cephalosporins = betalactams

• have roughly the same spectrum as non-potentiated Penicilins

• Inactivated by beta-pacts made producing bacteria

• Has a similar action to the Penicilins and interefere with cell wall synthesis of bacteria

• Prefix: Ceph or Cef

Cephalosporins prefix

Ceph or cef

Pharmacokinetics of cephalosporins

• Metabolized by the liver

• Excreted by the kidneys

• Poor CNS absorption

• Crosses placenta, udder, concentrates in urine

• Lower incidence of sensitivity reactions

Pharmacodynamics of Cephalosporins

• It is similar to penicillins

• Interferes with cell wall synthesis

• Binds to cell wall synthesizing proteins

• Causes bacterial cells to burst

• Bacterialcidal

Clinical uses for cephalosporins

• Cystitis

• Skin

• Soft tissue infections

• Mastitis

• Shipping fever in cattle

• Ceftiofur ( Naxcel) common drug used in dairy cattle and poultry

• Commonly used in dairy cattle and poultry

Side affects of cephalosporins

• Allergic reactions ( less often than penicillins)

• Fever

• Rashes

• Anaphylaxis

• Anorexia, vomiting diarrhea

• Those who have reactions to penicillins may have a reaction to this

Carbapenems

• Cell wall inhibitors

• Bacteriocidal

• Reserved for serious infections

• Ertapenem

• Imipenem-cilastatin

• Meropenem

Tetracyclines suffix

Cycline

tetracyclines drug class

• Absorption affected by food, especially milk and antacids ( do not give with food)

• Inhibits protein synthesis by the bacteria ( stops cell divisions) by binding to ribosome

• Bacteriostatic and broad spectrum

• Lots of resistance is seen

• Highly lipophilic ( good tissue penetration and longer half life)

• Metabolized by the liver

• Eliminated by the kidney

• Can go through the blood brain barrrier

Can tetracyclines go through the blood brain barrier

Yes they are able to go through the blood brain barrier.

Is the absorption of tetracycline affected by food

Yes absorption is affected by food, especially milk and antacids

What is mechinamism of actions for tetracyclines

Inhibits protein synthesis by the bacteria (. Stops cell divisions) by binding to ribosomes

Is tetracyclines Bacteriostatic and broad spectrum

Yes it is

Do terracyclines have resistancey

Yes lots of resistency is seen

Is tetracyclines highly lipophilic

Yes it is

What are tetracyclines used for

• used for tick borne diseases( riicketsial) and respiratory illnesses

• Used in large animals and small animals

Side affects of tetracyclines

• Can cause tooth enamel and dentin to turn brown/ yellow ( should not be given to babies for that reason)

• Anorexia, vomiting, diarrhea

• Cats even less tolerant-fever depression, abdominal pain

• Do not give tablets to cats it can cause esophageal stricture

• Higher doses can be hepatotoxic

• Interferes with bone growth ( do not give to babies)

• doxycycline has seem CNS penetration

• Never give IV to horses

What can tetracyclines causes in young animals

• Can cause tooth enamel and dentin to turn brown/yellow

• Interferes with bone growth

What can tetracyclines cause in cats when given in tablets

Can cause esophageal stricture if tablets or capsules are given to cats

Aminoglycosides

• Are big guns of antibiotics

• Bacteriocidal and broad spectrum

• Used for gram - bacteria

• Affects the ribosomes in protein synthesis

• Given parenterally or topically

• Not absorbed well orally ( not given po typically)

• Tend not to reach therapeutic concentrations in bile, CNS, prostate, respiratory or ocular

Aminoglycosides suffix

• Mycin - micin

  • Don’t confuse with tetracyclines except for amikacin

Aminoglycosides drugs

• Amikacin ( injectable form) ( common)

• Gentamicin

• neomycin ( topical)

• Spectinomycin

• Tobramycin

• Apramycin

Is Aminoglycosides absorbed well orally

No it is not usually not given po

Aminoglycosides side effects

• Can accumulate in the kidney cells and inner ear. Toxicity can occur in theses tissues ( renal toxicity and deafness)

• Concentrates in the kidneys and will cause damage

• Can cause cardio toxicity

• Diarrhea

• Did not mix with other antibiotics in the same syringe or IV line

When giving Aminoglycosides what do you want to make sure the patient is

Want to make sure the patient is well hydrated and has good kidney function

How is Aminoglycosides eliminated

Through the kidneys

Where does Aminoglycosides Accumulates and what does it cause

it will accumulate in the kidney cells and the inner. This will cause renal toxicities and deafness

what are the adverse events seen with Aminoglycosides

• Can cause nystagmus and vestibular disease in cats

• More common in cats but can cause deafness in dogs

• Should be avoided in working dogs

• Renal toxicity

Clinical uses of Aminoglycosides

• Pneumonia

• bacterial enteritis

• Conjunctivitis

• Skin and soft tissues

• UTI

• Endometriosis

Suffix for Fluroquinolones

Floxacin ( not all, but most have it)

Fluoroquinolones Pharmacokinetics

• Absorbed well oral route, parenteral, topical

• Rapidly distributed

• Metabolized by the liver

• Excreted by the kidney

Fluoroquinolones Pharmacodynamics

• Inhibits bacterial enzyme DNA Gyrase ( could the DNA so it will fit inside to supercool DNA)

• Attack enzymes needed to supercool DNA

• It is broad spectrum and bacterialcidal

Is Fluoroquinolones broad spectrum

Yes it is

Are Fluoroquinolones bacterialcidal

Yes they are

Can Fluoroquinolones get past the blood brain barrier

Yes it can get past the blood brain barrrier

Fluoroquinolones clinical uses

• bacterial skin and soft tissue infections

• Has great bioavailability

• Reaches eye, prostate CSF ( bone, skin, placenta)

• Bacteriocidal

• UTI

• Sepsis

Is Fluoroquinolones Bacteriocidal

Yes it is

Is Fluoroquinolones a broad spectrum antibiotic

Yes it is and it should not be used as a first line antibiotic.

Examples of Fluoroquinolones

• Ciprofloxacin ( Cipro)

• Difloxacin ( dicural)

• Enrofloxacin ( baytil)

• Orbiflozacin ( orbax)

• marbofloxacin ( Noroxin)

• Danoflaxacin

• Pradofloxacin

Adverse affects of Fluroquinolones

• Can affect cartilage in young growing animals( bubble type lesion) and show up later in life as arthritic change ( not used in young growing animals ( does not show up right away)

• Can cause CNS stimulation ( avoid in animals with CNS disorders)

• enrofloxacin should be avoided in cats as it can cause retinal degeneration ( blindness)

• Not to be used in food producing animals

Can Fluroquinolones be used extra-labelly in food animals

No it should not be used extra label

What can cause in the cartilage in Fluoroquinolone

• In young animals it can create a bubble type lesion that will show up alter in life as arthritic changes

• Should not be used in young animal due to potential cartilage damage.

Can Fluoroquinolones be used in food anaimls

Not it should not be used in food anaimls

What are systemic fungal infections and why are they serious?

• Systemic fungal infections occur when fungi infect internal body systems such as the blood, brain, lungs, or other organs.

• Characteristics:

  • Often life-threatening

  • Difficult to treat

  • Frequently occur in immunocompromised patients

Examples of systemic fungal diseases include:

• Histoplasmosis

• Blastomycosis

• Cryptococcosis

• Coccidioidomycosis

• Aspergillosis

• Candidiasis

What are superficial fungal infections?

Superficial fungal infections affect skin or mucous membranes rather than internal organs.

examples of superficial fungal infections

• Ringworm (dermatophytosis)

• Candida infections

  • These infections are typically easier to treat than systemic infections.