Antibiotics Flashcards
Bactericidal antibiotics
KILL, need a growing microbe
Bacteriostatic antibiotics
ONLY suppress the growth of microorganisms
Selective toxicity
Antimicrobial drugs have selective toxicity that can injure/kill the target cell or organism without injuring host cells
Resistome
Group of all existing antibiotic resistance genes in the world
Acquired resistance
Microbe is resistant to an antibiotic due to the presence of a resistance gene that is not innately present in other related bacteria. MUY MALO
Innate resistance
Any of the above types of resistance the noted in a non-pathogenic strain of bacteria
Clinical resistance
Any of the above types of resistance when noted in a PATHOGENIC strain of bacteria
Antibiotic MOA simplified
Any antibiotic given will create: selective pressure by killing sensitive organisms and by favoring the survival and expansion of resistant organisms
Antibiotics in Food
- 80% of all antibiotics used in the states
- Used for growth promotion: administer antibiotics dairy to help overcome the effects of crowded and unsanitary living conditions
- puts weight on faster, brings more profit in
Bacterial Persistence
- from dormant bacteria
- leftover cells that survived the antibiotics
Super-sanitization
-antibiotic misuse and over reliance
-hand sanitizer rather than wash
-Chemical all surface sterilization
Spurs evolution of HIGHER virulence levels
Extended sanitization
-Handwashinga nd basic antiseptics
-Sterile medical equipment
-Chemical treatment of wounds and severe contagious diseases
Keeps virulence levels CONSTANT
Baseline sanitization
-Clean food/water
-Garbage removal
-Separating infected from susceptible
Encourages evolution of LOWER virulence levels
Potency
Drug concentration required to exert an antimicrobial effect
Minimum inhibitory concentration (MIC)
Measure of potency; amount of drug required to produce a given % of its maximal effect
-a drug can be very potent but poor efficacious. A drug can b effective at low doses but the response may not change even when the dose is increased
Synergism (Potentiation)
When taken together, some antibiotics increase each other’s effectiveness to increase additive effects.
Antagonism
interaction in which one chemical partially or completely inhibits or counteracts the effect of the other. They can cancel or diminish each other’s therapeutic effect
How can we decrease antibiotic microbial resistance?
- Do not discontinue use prematurely
- Do not prescribe for viral infections
- Use a narrow spectrum 1st
- Use a older or first gen drug first
- Doses must be appropriately spaced to maintain therapeutic levels in patient
Types of Combination Therapy
-Additive: add together in effectiveness (1+1=2)
-Potentiative/Synergistic: increasing together in effectiveness. 1+1=5
Antagonistic: Bacteriostatic agent and a bactericidal drug
Penicillins (General Info)
Category: Drugs that weaken the bacterial cell wall
-have variable R side chain which influences acid stability, penicillinase resistance, and ability to bind specific penicillin-binding proteins. Penicillins will kill MOST
Narrow-spectrum penicillins (penicillinase sensitive)
-Penicillin G (IV)
-Penicillin V (oral)
Kills: strep species, neisseria species, many anaerobes, spirochete
Narrow-spectrum penicillins-penicillinase resistant (anti staphylococcal penicillins)
- Methicillin (not available)
- Nafcillin (IV)
- Oxacillin (IV, oral)
- Dicloxacillin (oral)
Extended-spectrum penicillins (aminopenicillins)
- Ticarcillin (IV)
- Pipercillin (IV)
MOA Penicillins
B-lactam ring: weakens cell wall by binding to bacterial penicillin binding proteins
- Inhibition of transpeptidases (enzymes that form bacterial cell wall)
- Activate autolysis which promote the active destruction of the cell wall
Penicillin-resistant bacteria: have B lactamase enzyme
Beta-lactamase inhibitors combined with penicillinase-sensitive penicillins, antimicrobial spectrum is extended
Drugs 4 penicillin-resistant bacteria
ampicillin+sulbactam=Unasyn
-amoxicillin + clavulanic acid = Augmenten
- Ticarcillin + clavulanic acid = Timentin
Piperacillin + tazobactam = Zosyn
Ceftazidime + avibactam = Avycaz
Side Effects of Penicillins
- Allergic reaction most common
- GI disturbances- superinfection
Penicillin Overdose
- Overdose symptoms: neuromuscular hypersensitivity, agitation, hallucinations, confusion, seizures
- monitor KIDNEY function (penicillins eliminated by the kidneys
- consider counter-ion
Cephalosporins
- B-lactam antibiotics (similar structure to penicillins but have an R2 group)
MOA: disrupt cell walll synthesis, lik epenicillins; activate autolysis
