Term
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Definition
-Rifamycin binding near the active site of RNA polymerase
-Antimicrobial agents: RNA polymerase inhibitors
-Bactericidal |
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Term
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Definition
| Macrocyclic antibiotics that inhibit DNA-dependent RNA polymerase, Bactericidal |
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Term
| Rifampin (Rifadin) and rifabutin (Mycobutin) |
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Definition
extremely effective antibiotics against both gram positive and
gram negative organisms, including strains of Staphylococcus (Staph) aureus (including Methicillin Resistant S. aureus
[MRSA], Pseudomonas, Klebsiella, Proteusetc. |
|
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Term
| Rifampin (Rifadin) is very effective against mycobacteria especially: |
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Definition
| Mycobacterium tuberculosis (rifampin), as well as M. aviae |
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Term
| rifabutin (Mycobutin) is Very effective against |
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Definition
|
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Term
| rifabutin (Mycobutin) is Very effective against |
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Definition
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Term
| Rifampin (Rifadin) and rifabutin (Mycobutin) bind to beta subunit of bacterial enzyme but do not bind to: |
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Definition
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Term
| Rifampin (Rifadin) and rifabutin (Mycobutin) are administered most often in combination with: |
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Definition
-isoniazid in thetreatment of tuberculosis—first line treatment
-Combination therapy prevents emergence of resistant tubercle bacilli |
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Term
| Rifampin (Rifadin) and rifabutin (Mycobutin) are used in the prophylaxis against: |
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Definition
| meningococcal disease—Penetrate into the CNS |
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Term
| Rifampin and Rifabutin are potent stimulators of microsomal enzymes: |
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Definition
- They decrease half life of other drugs—Drug-Drug interaction.
-Cause discoloration of urine and tears—Patients should be warned not to wear contact lenses during rifamycin treatment |
|
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Term
| Side Effects of Rifampin and Rifabutin |
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Definition
| Hepatitis (1%) or leukopenia and thrombocytopenia (rifabutin) |
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Term
| Antimicrobial agents: Protein synthesis inhibitors |
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Definition
Aminoglycosides,
tetracyclines
glycylcyclines,
chloramphenicol
lincosamides,
streptogramins
oxazolidinone
macrolide
ketolide antibiotics |
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Term
| Drugs or drug class targeting 30s ribosomal subunits: |
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Definition
-Aminoglycosides
-Spectinomycins
-Tetraciclines
The side of action of these drugs is 16s rRNA. |
|
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Term
| Mechanism of action of aminoglycoside: |
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Definition
| Induce misreading, halt protein synthesis at higher concentration. |
|
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Term
| Mechanism of action of Spectinomycin |
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Definition
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Term
| Mechanism of action of Tetracycline |
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Definition
| Inhibit aminoacyl tRNA binding to A site. |
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Term
| Drugs or drug class targeting 50s ribosomal subunit: |
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Definition
-Microlide
-Lincosimides
-Chloramphenicol
-Streptogramins
-Oxazolidinones
The side of action of these drugs is 23s rRNA |
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Term
| Mechanism of action of Microlides: |
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Definition
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Term
| Mechanism of action of Chloramphenicol |
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Definition
| Inhibit peptidyl transferase by interfering with the tRNA positionning. |
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Term
| Mechanism of action of Lincosimides |
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Definition
| inhibit peptidyl transferase by blocking the growing polypeptide chains and by inhibiting A and P sites |
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Term
| Mechanism of action of Streptogramins: |
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Definition
Inhibit peptidyl transferase;
Probable overlap with mechanism of action of Microlides; |
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Term
| Mechanism of action of oxazilidinones: |
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Definition
|
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Term
| First in class of Aminoglycosides: Bactericidal protein synthesis inhibitors |
|
Definition
streptomycin (1944),then neomycin,
kanamycin (Kantrex), |
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Term
| The 3 most widely used because of higher potency and lower toxicity drug in aminoglycoside class: |
|
Definition
gentamicin (Garamycin) (1963)**,tobramycin (Nebcin)**,
amikacin (Amikin)** |
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Term
| the drug of choice for many gram negative infections, e.g.urinary tract infections, pneumonia, sepsis, meningitis, peritonitis |
|
Definition
is Gentamicin
Side Effects: Nephrotoxicity and ototoxicity [mitochondrial metabolic
block] limits the usefulness of streptomycin but especially kanamycin (8-26% patients develop these) |
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Term
| What drugs combination is used in the treatment of streptococci or enterococci ? |
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Definition
| Combinations of penicillin or vancomycin plus streptomycin or gentamicin |
|
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Term
| the most active aminoglycoside against Pseudomonasor Proteus is: |
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Definition
Tobramycin
. Low level of penetration of amino glycosides in CNS and moderate level of penetration in lungs—difficulty in use as monotherapies |
|
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Term
| Resistance to aminoglycosides develops: |
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Definition
metabolic conversion of the active molecule of the aminoglycoside by transferases, for example
acetylation—Plasmid-mediated genetic transmission of resistance—oraltered porin structure or 30S ribosome structure mutation |
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Term
| Capreomycin- Bacteriostatic |
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Definition
is a 30s subunit protein synthesis inhibitor re-introduced
for the treatment of tuberculosis with multiple drug resistance. Toxicity is a major problem |
|
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Term
| Spectinomycin—Bacteriostatic |
|
Definition
Structural analog of Aminoglycosides but binds at different site on 16S rRNA of 30S subunit
Permits formation of 70S complex
Inhibits protein synthesis
No misreading of mRNA and no inappropriate protein synthesis
Alternative therapy of gonorrhea (Neisseria gonorrheae) infections
Administered as an injectable—No serious side-effects |
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Term
| Tetracyclines and Glycylcyclines—Broad spectrum, bacteriostatic protein synthesis inhibitors |
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Definition
Site of action is protein synthesis, in particular the binding of charged t-RNA
More selective for bacterial protein synthesis
First of the truly broad spectrum antibiotics—effective against atypicalas well as typical pathogens: |
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Term
| Doxycycline is not as good against |
|
Definition
| S. aureus, S. pneumoniae but tigecycline is |
|
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Term
| Resistance to tetracyclines has limited their use as broadspectrum antimicrobials—except for newest entry: |
|
Definition
-the tigecycline (an IV drug)
-Tigecycline is effective as treatment of multi-drug resistant (MDR) gram negative organisms such as Pseudomonas aureginosa, Klebsiella, and Acetinobacter baumannii—80-85% effective |
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Term
| Tigecyline is also effective against : |
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Definition
-Vancomycin Resesistant Enterococcus (VRE) infections and MRSA
-FDA approved Tigecycline for the treatment of complicated skin and
skin structure infections (cSSI), complicated intra-abdominal infections(cIAI), and community acquired pneumonias (CAP) |
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Term
| Side effects of tetracyclines: |
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Definition
Interactions of tetracyclines with divalent cations—Ca2+ (bone/tooth accumulation & discoloration); kidney
damage and GI distress |
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Term
Macrolide antimicrobials are
bacteriostatic protein synthesis inhibitors |
|
Definition
Introduced in the 1950's--include erythromycin (E-mycin),azithromycin (Zithromax), clarithromycin (Biaxin), and
telithromycin (Ketek)
-Useful in the treatment of pulmonary infections, including
Legionnaires’ disease (pneumonia) -Bacteriostatic, not to be used in treating conditions requiring
bactericidal activity, e.g., osteomyelitis, endocarditis, meningitis
-Most useful in the treatment of streptococcal infections, especially in individuals hypersensitive to penicillins—few if any resistant
streptococci to erythromycin
-Dosage varies from 500 mg/d (azithromycin, Z-pak and Z-max) to
500 mg/6h (erythromycin)—different PK characteristics |
|
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Term
| Other conditions treated with erythromycin: |
|
Definition
Mycoplasma pneumoniae,
Chlamydia,
diphtheria,
whooping cough (pertussis),tetanus,
acute syphilis and
gonorrhea |
|
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Term
| What combination drugs is use in the treatment of Helicobacter pylori—peptic ulcer disease? |
|
Definition
| clarithromycin, lansoprazole and amoxicillin (Prevpac) |
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Term
Chloramphenicol—Bacteriostatic and
bactericidal protein synthesis inhibitor |
|
Definition
Chloramphenicol (Chloromycetin) binds to 50 S ribosome and inhibits
transpeptidase reaction, blocks elongation of protein chain
2. Also causes inhibition of mitochondrial
ribosomes in eukaryotic cells
3. Resistance due primarily to the
expression of plasmid-encoded
acetyl transferases—drug inactivation
Introduced in 1948—Broad spectrum against gram + and gram –
bacteria, both aerobic and anaerobic
-H. influenzae, Neisseria meningitides, Bacteroides
-Is not used much because of severe toxicity, in particular aplastic
anemia, hypoplastic anemia, agranulocytosis and thrombocytopenia,i.e., partial or complete shutdown of the bone marrow
-1 in 30,000 doses administered associated with bone marrow
problems
-Drug interactions with: phenytoin, warfarin (prolongation of activity) |
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Term
| Lincosamides—Clindamycin, Bacteriostatic |
|
Definition
-Clindamycin (Cleocin) used for severe anaerobic infections—
Bacteroides
-Blocks peptide bond formation—interacts with both A and P site
and resembles in its actions both chloramphenicol and macrolides
-Causes Pseudomembranous colitis as a result of Clostridium
difficile growth in the GI
-Beware of inducible resistance during treatment by this
antimicrobial or macrolides or streptogramin
-Used in the treatment of fasciitis, skin/soft tissue infections, and
intra-abdominal infections with anaerobic bacteria—Normal dosage:300 mg/6h |
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Term
| Streptogramins, Quinupristin/Dalfopristin (Synercid)—Bactericidalagainst most sensitive bacteria |
|
Definition
Approved (1999) for the treatment of Enterococcus faecium and
Streptococcus pyogenes;
Approved for the treatment of Vancomycin-resistant enterococci
(faecium) [VRE] and for methicillin resistant S. aureus [MRSA] and
Streptococcus pyogenes
23S rRNA/ 50S ribosome binding—Inhibition of peptidyl transferase and emergence of growing peptide chain
―Irreversible‖ inhibition of 50S subunit |
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Term
| Oxazolidinones—Linezolid (Zyvox) |
|
Definition
Exact site of action not known but suspected to be 23SrRNA
Effective against MRSA, penicillin-resistant
Streptococci, and vancomycin-resistant Enterococci
(VRE)
Useful in the treatment of Multi-Drug Resistant
organisms such as A. baumannii |
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