Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
45 Cards in this Set
- Front
- Back
|
Affect bacterial cell wall
|
1. penicillins
2. cephalosporins |
|
|
General principles that allows penicillins and cephalosporins to work?
|
- active cells constantly produce new peptidoglycan and transport to cell envelope
- PCN and cephalosporins react w/ enzymes (PBP) required to complete process - active when cell is growing - weaken cell wall --> lysis |
|
|
PCN and cephalosporins are categorized as what kind of antibiotics?
|
Bactericidal antibiotics
|
|
|
What 3 parts make up penicillin and its relatives?
|
1. thiazolidine ring
2. beta-lactam ring 3. R group |
|
|
Of the 3 parts that make up PCN, which interacts with bacterial transpepsidases (PBP)?
|
Beta-lactam ring
|
|
|
Of the 3 parts that make up PCN, which affects biological activity?
|
R- group attached to ring affects bio activity
|
|
|
What is penicillinase/beta-lactamase?
|
Bacteria produce enzymes to break down PCN by splitting the beta-lactam ring of PCNs
|
|
|
Which antibiotics are resistance to penicillinases?
|
Methicillin
Nafcillin |
|
|
What is the primary problem in therapy w/ PCNs?
|
Allergic rxn and resistance in strains of bacteria
|
|
|
What are beta-lactamase inhibitors?
|
- suicide inhibitors of beta-lactamase
- beta-lactams that bind to and inactive beta-lactamase enzymes - expand spectrum of beta-lactam antibiotics |
|
|
Examples of beta-lactamase inhibitors?
|
clavulanic acid
sulbactam clavulanate + amoxicillin = augmentin clavulanate + ticarcillin = timentin |
|
|
How are cephalosporin drugs similar to PCNs?
|
- similar structure
- same mechanism of action |
|
|
Do PCNs or cephalosporins account for the majority of all antibiotics administered?
|
Cephalosporins
|
|
|
What are the advantages of using cephalosporins?
|
- resistant to most PCNases
- cause fewer allergic rxns - administered parenterally |
|
|
What is the 1st generation of cephalosporins?
|
1st - cefazolin & cephlathin
|
|
|
What is the 2nd generation of cephalosporins?
|
2nd - cefaclor & cefonacid
|
|
|
What is the 3d generation of cephalosporins?
|
3rd - cephalexin & cefotaxime
|
|
|
What is the 4th generation of cephalosporins?
|
4th - cefpirone & cefepime
|
|
|
What other drugs target cell walls?
|
cavitracin
isoniazid (mycobacterium tuberculosis) canvomycin |
|
|
What antimicrobial drugs disrupt cell membrane fnxn?
|
Polymyxin
|
|
|
What is polymoxin and why is its use limited?
|
antimicrobial drug that disrupts cel membrane and because of toxicity to kidneys
|
|
|
What are the 3 classes of drugs that target DNA or RNA?
|
1. quinolones
2. rifmycin 3. metronidazole |
|
|
What is the mechanism of action of quinolones?
|
Inhibits DNA topoisomerases (gyrases)
|
|
|
How are fluoroquinolones better?
|
- higher potency
- broad spectrum - inhibit wide variety of gram +/- bacterial species w/ minimal conc. |
|
|
What class of drugs and which particular drugs are used for UTI, STDs, gastrointestinal infxns, osteomyelitis, resp. infxns, soft tissue infxns?
|
Quinolones
ciprofloxacin and norfloxacin |
|
|
What is the mechanism of action of rifamycin (rifampin)?
|
Inhibits DNA dependent RNA polymerase, preventing RNA syn
|
|
|
What is rifamycin MAINLY used for?
|
infxn by several gram + rods and cocci and few gram - bacteria
|
|
|
What others uses have rifamycin commonly had in the past?
|
Tx of mycobacterial infxs such as tuberculosis and leprosy
|
|
|
Of the drugs presented, which class/drug has a narrow spectrum?
|
Cell membrane fnxn disrupting drugs/ polymyxin
|
|
|
- What is the mechanism of action of metronidazole?
- What reduces the compound? |
- Reduced form acts as free radical that damages bacterial DNA
- some anaerobic bacteria produce nitroreductase that reduces compound |
|
|
How do antibacterial drugs that block protein synthesis work?
|
Most react w/ the ribosome-mRNA complex
|
|
|
What are the 7 classes of drugs that block protein synthesis?
|
1. aminoglycosides
2. tetracyclines 3. macrolides 4. chloramphenicols 5. clindamycin 6. streptogramin 7. oxazolidones |
|
|
What are aminoglycosides used for?
|
Tx serious infxns caused by many gram -'s and some gram +'s
|
|
|
What are classified as aminoglycosides?
|
Streptomycin
neomycin kanamycin gentamicin tobramycin amikacin spectinomycin |
|
|
Aminoglycosides are described as being __________ (their effect on bacteria)
|
bactericidal
|
|
|
Tetracyclines are described as being _________ (their effect on bacteria)
|
bacteriostatic
|
|
|
What are classified as tetracyclins?
|
1. tetracycline
2. doxycycline 3. minocycline |
|
|
Macrolides are described as being ________ (effect of bacteria)
|
bacteriostatic
|
|
|
What are classified as macrolides?
|
1. erythromycin
2. azithromycin 3. clarithromycin |
|
|
What are the physiological advantages of macrolides?
|
- broad spectrum
- low toxicity - used for wide variety of gram -/+'s |
|
|
- Which drug is restricted due to its high human toxicity?
- what type of drug is it (general mechanism of action) |
- Chloramphenicol (tx typhoid fever)
- protein synthesis blocking drug |
|
|
- Which drug has a broad spectrum, but has limited application due to its adverse affect on the GI tract?
- what type of drug is it (general mechanism of action) |
- clindamycin
- protein synthesis blocking drugs |
|
|
Which drug is effective against Staph and Enterococus, and against resistant strains of Strep?
|
Streptogramin (synercid)
|
|
|
What is special about oxazolidones in terms of clinical pathogenic use?
|
Used to tx 2 of the most difficult clinical pathogens - MRSA and VRE
-- not found in nature |
|
|
What is the mechanism of action of sulfonamides and trimethoprim?
|
Inhibit folic acid synthesis
- sulfa inhibits PABA to DHF - trimethoprim inhibits DHF to THF |
