Antiinfective drugs Flashcards
Types of microorganisms
Bacteria
Fungi
Viruses
Protozoa
bacteriostatic antibiotics
Inhibit the growth of bacteria
bactericidal antibiotics
Kill bacteria
in vitro
artificial environment
minimum inhibitory concentration
(MIC) is the lowest level of antibiotics that will stop the growth of the organism and gives an idea of how resistant the organism will be to the antibiotic.
Aminoglycosides
antibiotic
bactericidal antibiotics that inhibit protein synthesis in bacteria.
These drugs are concentrated at high levels in the kidneys
these include the: Aminocyclitols, Gentamicin,
Carbapenems
antibiotic
Usually bactericidal because they inhibit bacterial cell wall synthesis
Only human meds exist
Cephalosporins
Bactericidal and interfere with bacterial cell-wall synthesis.
Generally excreted through the kidneys.
Many different kinds exist
Whether they work against gram-negative or gram-positive or both depends on the generation.
Examples- Cephalexin (1st generation, gram positive), Cefazolin (2nd generation, gram negative)
Macrolides
Antibiotics primarily effective against gram-positive organisms.
many inhibit protein synthesis
Generally excreted through bile
Examples include erythromycin, tulathromycin, azithromycin, and tylosin.
can cause diarrhea and vomiting in small animals.
Can cause diarrhea in both ruminants and horses.
lincosamides
Antibiotics
primarily effective against gram-positive organisms.
Also effective against anaerobes and toxoplasma parasites,
used to treat wounds, abscesses, and dental infections.
Lincosamides are distributed into most tissues and can cross the placenta.
Are partially metabolized in the liver.
Unchanged drug and metabolites are excreted in the urine, feces, and bile.
Bonus: Example clindamycin
Polymyxin B and bacitracin
Used topically to treat skin and eye conditions.
Often combined with other drugs such as steroids or neomycin.
Penicillin
bactericidal
effective against gram-positive microorganisms and tend to be excreted through the kidneys and urine.
mechanism of action is to bind to enzymes involved in cell-wall synthesis in bacteria.
ALL THIS IS BONUS —bacteria eventually burst and die, because their cell wall breaks down.
resistance to penicillins is through an enzyme called beta-lactamase (penicillinase).
The addition of a chemical such as clavulanic acid (which inhibits beta-lactamase)
–called potentiated penicillins.
examples amoxicillin and amoxicillin/clavulanate.
Tetracyclines
are bacteriostatic
At very high doses, they’re bactericidal.
They have a wide spectrum of activity against gram-positive and gram-negative bacteria.
Most are excreted through the kidneys.
Examples- tetracycline and doxycycline
Bonus- If given to young can permanently stain the teeth of young animals (younger than six months)
Quinolones and Fluoroquinolones
Bactericidal
It’s believed they prevents DNA supercoiling and DNA synthesis
They work against gram-negative bacilli and cocci
Eliminated through the production of bile by the liver and urine by the kidneys
- An example is enroflaxin (fluoroquinolones)
Bonus
Spread rapidly into the tissues and body fluids
Quinolones and Fluoroquinolones contraindications
Should not be used in growing animals because they may cause cartilage abnormalities
Some fluoroquinolones are prohibited for use in cattle
beta-lactamases
an enzyme that degrades beta-lactam antibiotics (penicillin) before they reach the bacteria’s cell wall.
Sulfonamides
Bactericidal drugs with a broad spectrum of activity against gram-positive and gram-negative organisms.
also works against some protozoa
Kidney/liver
Sulfonamides warnings
may also cause keratoconjunctivitis (inflammation of the eye and eyelid) and may be associated with autoimmune-mediated hemolytic anemia in small animals.
anti-viruls
not commonly used
can be used for herpes eye infections in cats or Pacheco’s virus (herpesvirus infections in birds)
Interferon alfa has been used in cats to treat eye and skin diseases.
Alcohol (as a cleaning agent)
kills bacteria, some viruses, and tuberculosis, although it doesn’t affect spores or fungi.
doesn’t penetrate organic material
Formaldehyde
is effective against spores, bacteria, fungi, and viruses on inanimate objects.
Bonus-
Toxic to the skin and mucous membranes
Formaldehyde requires a long time to work and doesn’t work well with organic material.
Chlorines and iodines
Kill Bacteria, Viruses, Fungi, Tuberculosis
Chlorines are used to clean floors and other hard surfaces. Iodines can be used to disinfect an animal’s skin before surgery, used against bacterial spores and also be used to sanitize food dishes and utensils.
Zoonotic –
disease from animal can affect you,
include roundworms, hookworms, toxoplasmosis, and trichinella
A disinfectant
is primarily for use on inanimate (not alive) objects
to kill microorganisms or inactivate viruses.
hospital based infections
nosocomial
Antiseptics
are for use on living tissues to kill
microorganisms
Antimicrobials that inhibit cell wall synthesis -info and examples
Drugs that interfere with bacterial cell wall formation can kill or inhibit bacterial organisms only when the bacteria are growing or dividing.
- Penicillins
- Cephalosporins
- Bacitracin
- Vancomycin
Damaging the bacterial cell membrane alters its barrier and allows antimicrobial drugs to enter and leave the cell. Give one example
- Polymixin B
Antimicrobials that inhibit protein synthesis - info and examples
Antimicrobial drugs target bacterial protein synthesis by binding to the ribosomes and disrupting the bacteria’s metabolism leading to inhibition of growth or death.
- Aminoglycosides
- Tetracyclines
- Macrolides
- Lincosamides
- Chloramphenicol
Antimicrobials that Inhibit nucleic acid synthesis -info and examples
Antimicrobial drugs bind to components involved with DNA and RNA synthesis and interfere with division and survival.
* Fluoroquinolones
* Metronidazole
* Rifampin
Antimicrobials that inhibit metabolic processes -info and examples
These drugs interfere with cellular processes (block or bind to bacterial enzymes) essential for the bacteria’s survival.
* Sulfonamides
Gram-positive bacteria
A type of bacteria that have a thick cell wall.
This cell wall helps protect the bacteria from antibiotics and other substances that might damage them.
Examples- staph and strep
Gram-negative bacteria
Gram-negative bacteria have an outer membrane that protects them against certain antibiotics, such as penicillin. When disrupted, this membrane releases toxic substances called endotoxins
Examples- Pseudomonas and e-coli
