Antibiotics Flashcards
what is Antibiotics
any compound (natural or synthetic) that inhibits the growth of, or actively kills micro-organisms
what are the principles of Antimicrobial Therapy
Identification of pathogen
–>acid fast stain
Susceptibility testing and resistance
–>put antibodies in bacteria cultures and see which one is the best at eliminating the bacteria
what are the types of antibiotics
- beta-lactasms
- Macrolides
- Quinolones
- Aminoglycosides
- Tetracyclines
- Sulfonamides
- Glycopeptides
What are 2 types of antibiotics action
bacteriocidal: kill bacteria
Bacteriostatic:
inhibit growth of susceptible bacteria, lead to bacteria death
What are the Four common mechanisms of action of antibiotics
- Interference with cell wall synthesis
- Interference with protein synthesis
- Interference with DNA replication
- Acting as a metabolite to disrupt critical metabolic reactions inside the bacterial cell
characteristic of Beta-Lactam Antibiotics
- Broad & most commonly used class of antibiotics
- has a B-lactam ring as the primary structure
- bactericidal
- Chemical manipulation of the side chain led to new agents with advanced spectrum of antimicrobial activity
what are some beta-Lactam Antibiotics
- Penicillins
- Cephalosporins
- macrolides
- tetracyclines
- Carbapenems
- ->merepenem
- ->doripenem
- Monobactams
- ->Aztreonam
What is the Mechanism of Action of penicillins
- Penicillins enter the bacteria via the cell wall
- Inside the cell they bind to penicillin-binding protein
- Once bound, normal cell wall synthesis is disrupted
- Result: bacteria cells die from cell lysis
*Penicillins do not kill other cells in the body
What is the indication of Penicillins:?
*narrow spectrum
Prevention and treatment of infections caused by Gram-positive bacteria
What is narrow-spectrum antibiotic
effective against only a specific group of bacteria.
What is narrow-spectrum antibiotic
effective against only a specific group of bacteria.
Examples of pencillins
amoxicillin
ampicillin
cloxicillin
methicillin
how does Antibiotic Resistance work in bacteria
- bacteria secrete beta lactamase
- which therefore breaks down the B-lactam ring inactivating the antibiotic
What is Staphylococcus aureus
a MRSA because it has beta lactmase
features of Cephalosporins
- Structurally related to penicillin
- bactericidal via inhibiting cell wall synthesis
What is the relationship between generation of Cephalosporins and its effectiveness?
increase in generation , less effectie against gram +ve
what are the side effects Cephalosporins
- hypersensitivity( undesirable reactions produced by the normal immune system, including allergies and autoimmunity.)
- headaches, dizziness
- Nausea & Vomiting
What are the 4 generation of Cephalosporins
- First-generation cephalosporins
- ->Wide variety of gram-positive organisms - Second-generation cephalosporins
- ->Gram-positive and some gram-negative organisms - Third-generation cephalosporins
- ->Active against most gram-negative organisms - Fourth-generation cephalosporins
- ->Extended gram-positive and gram-negative coverage
- ->for the sickest patients - fifth generation
- ->effective against MRSA
- ->gram +ve and -ve
- ->not effective against ESBL
What is ESBL
- EXTENDED-SPECTRUM BETA-LACTAMASE are Gram-negative bacteria that produce an enzyme beta-lactamase that has
- the ability to break down commonly used antibiotics, such as penicillins and
cephalosporins and render them ineffective for treatment
what is the Newest cephalosporin agents
cefepime, 4th generation
Broader spectrum of antibacterial activity than third generation, especially against gram-positive bacteria
features of macrolides
- broad spectrum
- -> cover gram +ve, -ve , atypical
*bacteriostatic
What are the side effect of macrolides
Upset GI
- need to take with food
- ->otherwise nausea, vomiting, dizziness and cramps
what are some macrolides drugs?
- erythromycin
- azithromycin
- clarithromycin
What is the MOA of macrolides
Prevent protein synthesis within bacterial cells
–>cell dies eventually
What is the indication of macrolides
Strep infections (gram +ve) --> Streptococcus pyogenes
Mild to moderate URI (gram -ve)
–> Haemophilus influenzae
what is the characteristics of tetracycline
Bacteriostatic
–>inhibit protein synthesis and cell growth
broad spectrum drug
Natural, semisynthetic
indication of tetracycline
Gram-negative, gram-positive protozoa Mycoplasma Rickettsia Chlamydia syphilis Lyme disease
What is the side effect of tetracycline
N, V & D
binds to ca2 and mg2
- ->don’t use with milk,
- ->kids (yellow stained teeth), –>pregnancy ( stops fetal bone growth)
what are some tetracyclines drugs
oxytetracycline
minocycline
features of Aminoglycosides
Bactericidal
–>prevents protein synthesis
Broad spectrum
–>mostly gram-negative; some gram-positive
- deal with Systemic infections(sepsis)
Potent antibiotics with serious toxicities
What are the toxcities comes with Aminoglycosides
nephrotoxicity, ototoxicity
What is the indication of Aminoglycosides
- kill gram-negative bacteria
- used in combination with other antibiotics (beta lactams) for synergistic effect
What are some example of Aminoglycosides drug
neomycin
gentamicin
streptomycin (TB)
tobramycin (CF)
features of Quinolones
bactericidial
broad spectrum
- gram-negative organisms and some gram-positive organisms
what is the MOA of quinolones
–>alters DNA of bacteria
what is the side effect of Quinolones
n, v & d
prolongation of q-t interval
liver & kidney toxicity arthropathy
What is some drugs of Quinolones
ciprofloxacin norfloxacin ofloxacin levofloxacin gatifloxacin
features of Sulfonamides:
Bacteriostatic action
–>Prevent synthesis of folic acid
indication of Sulfonamides
Treatment of Urinary Tract infections
–> caused by
Enterobacter spp., Escherichia coli, Klebsiella spp (gram-ve)
Staphylococcus aureus(gram -ve)
–>Treatment of prophylaxis of
Pneumocystis carinii pneumonia
–> Upper respiratory tract infections
features of vancoymic
Natural, bactericidal antibiotic
**treat MRSA and gram +ve infection
what is 1 down side of vancoymic
may cause ototoxicity and nephrotoxicity
monitor blood levels to ensure therapeutic levels and prevent toxicity
