Antibiotics Flashcards
Sulfonamides
• Sulfa Drugs are included in this
• Sulfonamides are Bacteriostatic
◦ Bacteriostatic: Doesn’t kill the bacteria but prevents the microbe from growing and reproducing by interfering with the folic acid synthesis.
• Affective against Gram(+) bacteria, UTI Gram(-) rods and tuberculosis
• Accumulate in the Kidneys which may not be good for a healthy kidney
• Many organisms are becoming resistant
• Often used in combination with other drugs to boost the effectiveness.
Penicillin
- Widely affective against Gram(+) bacteria
- Interferes with the Peptidoglycan Synthesis by making the bacteria cell walls weak and eventually causing the bacteria cell to die all together.
- Essentially Penicillin is effective at breaking down the Peptidoglycan layer that Gram (+) bacteria have.
Semi-Synthetic Penicillin
Available due to chemically modification in the lab broadening the spectrum of activity to be affective against Gram(-) bacteria.
◦ Most UTI bacteria’s are Gram(-) Rods
‣ Remember: Gram (-) Rods have a phospholipid layer which is what made Penicillin not as affective therefore making the semi synthetic version modifies the fungus allowing to break down that Phospholipid layer.
Give an example of a semi-synthetic Penicillin drug
Amoxicillin
‣ This is commonly prescribed for urinary tract infections
Amoxicillin is what type of antibiotic & commonly prescribed for?
Penicillin & UTI
Penicillin comes from?
• Penicillin is a form of bacterial mold called Penicillium
◦ Remember: Mold is a Fungi & have Spores
Cephalosporins are derived from?
• Derived or comes from a fungus called: Cephalosporium Acremonium
Cephalosporins purpose is?
• These drugs give us options when the bacteria has drug resistance as the drug may have a resistance to the first generation of the drug but not to the second generation or third generation or visa versa.
Cephalosporin Drugs
3 Generations of the Cephalosporin Drugs:
◦ 1: First Generation: Effective against Gram(+) bacteria & some Gram (-) Rods.
‣ Example: Cephalexin (Kefflex) & Cephalothin (Keflin)
◦ 2: Second Generation: Effective against Gram (+) & Gram (-) rods
‣ Example of the drug: Cefaclor & Cefoxitin
◦ 3: Third Generation: Effective against Gram (-) rods including Pseudomonas which is a huge deal since Pseudomonas can spore out and wait for their preferred environment making them a hard to kill bacteria.
‣ This generation of drug is not used widely since it is effective against Pseudomonas we do not want other bacteria’s to become resistant against this medication.
• Used in more severe cases like central nervous system diseases
‣ Example of the drug: Cefotaxime (Claforan)
Cephalosporin Drugs: First Generation
◦Effective against Gram(+) bacteria & some Gram (-) Rods.
‣ Example: Cephalexin (Kefflex) & Cephalothin (Keflin)
‣ Widely used & prescribed in both human & veterinary medicine
Cephalosporin Drugs: Second Generation
Effective against Gram (+) & Gram (-) rods
‣ Example of the drug: Cefaclor & Cefoxitin
Cephalosporin Drugs: Third Generation
◦Effective against Gram (-) rods including Pseudomonas which is a huge deal since Pseudomonas can spore out and wait for their preferred environment making them a hard to kill bacteria.
‣ Example of the drug: Cefotaxime (Claforan)
‣ This generation of drug is not used widely since it is effective against Pseudomonas we do not want other bacteria’s to become resistant against this medication.
• Used in more severe cases like central nervous system diseases
Cefotaxime is what type of Antibiotic?
- Cephalosporin Third Generation
Also called: Claforan
Claforan is what type of Antibiotic?
- Cephalosporins Third Generation
*Also called: Cefotaxime
Cefaclor is what type of Antibiotic?
Cephalosporin - Second Generation
*Also called: Cefoxitin
Cefoxitin is what type of Antibiotic?
Cephalosporin - Second Generation
*Also called: Cefaclor
Cephalexin
Cephalosporin - First Generation
* Also called: Kefflex
Cephalothin
Cephalosporin - First Generation
*Also Called: Keflin
Keflin
Cephalosporin - First Generation
* Also called: Cephalothin
Kefflex
Cephalosporin - First Generation
*Also called: Cephalexin
Aminoglycosides Antibiotics Include:
- Streptomycin
- Gentamycin
- Spetinomycin
- Neomycin
Streptomycin
• Derived from Aminoglycosides
• Discovered 1944
• Comes from a mold like bacterium that is commonly found in soil called: Streptoyces Griseus
• Over half of our antibiotics come from Streptomycin
• Bacteriosticial: Kill the bacteria
• Broad spectrum antibiotics
• Effective against bacteria that contain sticky capusles called Glycogygen
> Capsulated bacteria are called Mycobacterium
• Does not interfere with prokaryotic protein synthesis only interferes with the eurokyotic protein synthesis (Bacteria’s are eukaryotic).
> Messing with the protein synthesis makes it so the bacteria can no longer absorb nutrients from the host and therefore cannot reproduce and will eventually die.
• Can be very toxic to the host and cause other medical concerns such as: kidney damage and/or hearing loss therefore constant blood level monitoring is require
Gentamycin
• Derived from Aminoglycosides
• Affective against Proteus, E. Coli, Klebsiella, Serratia, Pseudomonas which are all Gram (-) Rods.
Spetinomycin
• Derived from Aminoglycosides
• Effective against Neisseria Gonorrhoeae
• Given via an intramuscular (IM) injection
Neomycin:
• Derived from Aminoglycosides
• Affective against Bacterial Conjunctivits (pink eye)
• Best if used in conjunction with other antibiotics like Polymuxin B and Bacitracin (Neosporin)
Tetracyclines
• Also a Streptomyces sp. derivative
• Natural Form: chlortetracycline & oxytetracycline
• Synthetic Form: tetracycline & doxycycline • Drug of choice for most rickettsia and chlamydiae
Rickettsia: Transferred through arthropod vectors (parasites) obligate intraceullar parasites meaning that they must be inside the host
Chlamydiae: Transmitted through aerolized and bodily fluid. Obliagate intraceullar parasite.
4. Broad spectrum antibiotic: Affective against Gram(+) and Gram(-) bacteria
Bacteriostatic: Does not kill but stops reproductions/spread
5. Interferes with protein synthesis
6. Can cause liver, kidney damage, yellowing of permanent teeth
Chloramphenicol
◦ Originally from Streptomyces, now made synthetically
◦ Bacteriostatic: Works by disrupting the bacteria protein synthesis
◦ First broad spectrum antibiotic
◦ Toxic – allergic reactions, depresses bone marrow function at the stem cell level causing aplastic anemia: meaing all the RBC, WBC, & Platelets which opens the animal up to a large number of secondary infections. (Aplastic means ALL)
◦ Used only in life threatening circumstances like Typhoid fever or meningitis and even than the provider is still weighing if the risk of Aplastic Anemia is worth the risk - if there is any other sort of treatment we will try that first due to the aplastic anemia side effect.
Fluroquinolones
◦ This antibiotic is completely synthetic meaning that it was lab created
◦ Broad spectrum antibiotics
‣ Meaning its effective against both Gram (+) & Gram (-) microbes
‣ Commonly used for GI Infections, STD, Neisseria, chlamydiae, Staphylococcus aureus, & Streptococcus pyogenes
◦ Bacteriocidal by inhibiting the bacteria DNA synthesis
◦ Does better against Gram (+) organisms
◦ Common known Vet Med Drug: Enrofloxacine (Baytril)
‣ Enrofloxacine (baytril) was the first drug created specifically for Vet Med unlike most drugs in vet med have been adopted from human medicine.
‣ Purple Entroic Tablets: Are preferred version of the drugs for exotic animals.- remember the Bunny story where they give them the purple pill w/ a scoop of jam
‣ Chewable Beef Tablets: Preferred for dogs and cats but bunnies do not like these flavor not matter how much Jam you covered it in.
◦ Common Human Drug Name: Ciprofloxacine (Cipro)
‣ This drug is effective against Anthrax and was given to first responders during the Anthrax mail attack after 911. Given via injection.
• Macrolides
◦ Erythromycin
‣ Produced from Streptomyces
‣ Bacteriostatic: By disrupting protein synthesis
‣ Most effective against G(+), G(-), & Mycobacteria
• Includes: Whooping Cough, Diptheria, Campylobacteria
‣ Commonly used in human medicine for people who are allergic to penicillin
‣ Childhood Core Vaccine: DTP: Diphtheria, Tetanus, Pertussis (Whooping Cough)
◦ Clindamycin, Lincomycin
‣ This antibiotic drug is used when the bacteria is resistant against penicillin
‣ Especially effective against Staphylococcus
‣ Effective against Anaerobes
‣ Antirobes Aqua Drops for Cats: Taste terrible, This is generally prescribed to older cats prior to a dental procedure, they are generally prescribed for a week. Its a drop put in the cats mouth generally 1ml of the drug - its extremely difficult to give to cats due to the awful taste.
‣ Negative Side Effects: Includes Clostridial overgrowth in intestines
• Clostridial are spore forming bacteria that are obligate anaerobes
Macrolides
2 Types:
1: Erythromycin
‣ Produced from Streptomyces ‣Bacteriostatic: By disrupting protein synthesis
‣ Most effective against G(+), G(-), & Mycobacteria
• Includes: Whooping Cough, Diptheria,
‣ Commonly used in human medicine for people who are allergic to penicillin
‣ Childhood Core Vaccine: DTP: Diphtheria, Tetanus, Pertussis (Whooping Cough)
Clindamycin &/or Lincomycin
‣ This antibiotic drug is used when the bacteria is resistant against penicillin
‣ Especially effective against Staphylococcus
‣ Effective against Anaerobes
‣ Antirobes Aqua Drops for Cats: Taste terrible, This is generally prescribed to older cats prior to a dental procedure, they are generally prescribed for a week. Its a drop put in the cats mouth generally 1ml of the drug - its extremely difficult to give to cats due to the awful taste.
‣ Negative Side Effects: Includes Clostridial overgrowth in intestines
• Clostridial are spore forming bacteria that are obligate anaerobes
Antibiotic Resistance
• different organisms can resist activity of some agents in different ways.
• Different bacteria have different forms of resistant
◦ Not all bacteria are resistant against the same agent
• Bacteria have a large population and can reproduce/replicate rapidly
◦ Bacterial mutations will occur utilizing the plasmids R factor to replicate the bacterial resistant DNA and create new resistant bacterial cells within the same generation
‣ Bacterial cells pass resistance by using their pili to attach to a bacterial cell behind them allowing them to share the drug resistant information through the R factors of their own plasmid & than the original bacterial cell will die. This cycle continues until lone survivors are left with the resistance in their plasmid allowing them to replicate/reproduce new bacterial cell that actually contain the resistant in their DNA.
Resistance Mechanisms:
• Prevent the drug from entering
◦ Penicillin G cannot pass through outer membrane of G(-) organisms
◦ Mycobacteria = glycocalyx = waxy, protects
• Pumped agent out of cell
◦ E. coli, Pseudomonas, S. aureus all have multi-drug resistance pumps
◦ Expel agents out of cell. Requires E
• Inactive Drug:
◦ Some bacteria contain an enzymes Penicillinase which splits/breaks apart the penicillin drug molecules making the drugs ineffective/inactive.
How to prevent antibiotic Resistance:
• Use high enough dose of the drugs and begin treatment during the “log phase” of the illness and getting the first dose of Abx in fast.
◦ Think of the first day of Abx being prescribed the first dose of Abx needs to be higher than the mainlanders dose and needs to be delivered quickly ideally via injection.
• Continue the antibiotic therapy even after the clinical signs/symptoms have subsided/gone away.
◦ This is so important because by introducing the antibiotics and not completing the treatment it introduces the Abx to the bacteria & now the bacteria are able to become resistant to the Abx.
• Use combination of drugs to lower probability that organism can develop two or more resistances
• Using cultures and sensitivity is sooo important and crucial for knowing which antibiotics would be best effective against that specific bacteria
