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MLT-Antimicrobial
Microbiology
Question | Answer |
---|---|
Antimicrobial agents can be further classified as ? | 1.Antibacterial, eg. Penicillin 2.Antiviral, eg. Tamiflu 3.Antifungal, eg. Amorolfine 4.Antiprotozoan, eg. Metronidazole |
What is the mode of action of antibiotic? | 1.Bacteriocidal: Kill 2.Bacteriostatis: Inhibit |
What are the 5 classification of antibiotics? | 1.Inhibition of cell wall synthesis 2.Inhibition of nucleic acid synthesis 3.Inhibition of protein synthesis 4.Disruption of cytoplasmic membrane 5.Inhibition of general metabolic pathway |
Whats the example of antibiotics that Inhibit cell wall synthesis? | 1.beta lactam 2.Vancomycin 3.Bacitracin |
Whats the example of antibiotics that inhibit nucleic acid synthesis? | 1.Quinlones 2.Rifampicin |
Whats the example of antibiotics that inhibit protein synthesis? | 1.Aminoglycosides 2.Macrolides 3.Oxozolidinones |
Whats the example of antibiotics that inhibit general metabolic pathway? | 1.Sulfonamides 2.Trimethoprim |
Whats the example of antibiotics that disrupt cytoplasmic membrane? | Polymyxins |
Whats the mechanism of beta-lactam ring? | 1. It mimic the subunit of peptidoglycan 2. Bind to Penicillin Binding Protein which promotes cross-linking 3. Cell wall then disrupt, and cell lyzes |
What are the 4 major groups of beta-lactam ring? | 1.Penicillins 2.Cephalosporins 3.Carbapenems 4.Monobactams |
Who discovred first antibiotics, Penicillin G? | Alexander Fleming at 1928 |
What enzyme makes Staphylococcus aureus resistant to natural penicillin ? | Penicillinase |
Penicillin are usually effective in against Gram _________ bacterial and example? | Positive, eg. GBS, Strepto. pyogenes |
What is the new penicillin developed for Staph. aureus? | Penicillinase-resistant Semisynthetic Penicillins |
What makes Penicillinase-resistant Semisynthetic Penicillins (PRSPs)special? | R group of Penicillin has been replaced by Methicillin |
Any other structural derivatives Penicillin that based on Methicillin ? | 1.Oxacillin 2.Cloxacillin 3.Dicloxacillin |
Which Penicillin derivative is usded for laboratory susceptibility test? | Oxacillin |
A and B now are resistant to PRSPs, what are they? | A.S.aureus (MRSA) B.S.epidermidis (MRSE) |
What are the broad spectrum penicillins that can act on gram positive and gram negative bacteria? | 1.Ampicillin 2.Amoxycillin |
Which bacterial is naturally resistant to broad spectrum penicillin and why? | Pseudomonas, it has AmpC β-lactamase to cleave beta-lactam ring |
What are the anti-pseudomonal penicillins? | 1.Piperacillin 2.Ticarcillin |
Piperacillin/ ticarcillin can also be used to treat gram ____A____ and ____B_____ bacteria? | A. negative 2.anaerobic |
What is the difference between Cephalosporin group and the penicillin group? | Cephalosporin group: 6-C ring + beta-lactam ring Penicillin group: 5-C ring + beta-lactam ring |
How many generations of Cephalosporins? | 5 |
What are the 1st generation Cephalosporins developed for A and B? | Cephalothin, cephalexin A:Staphylococci B:Streptococci |
MRSA, MRSE and Enterococci are resistant to all ________ generation of Cephalosporins drug? | 1st to 3rd |
What are the examples of 4th generation of Cephalosporins? | Cefepime |
What makes Cefepime so useful (3 reasons) | 1.Broad spectrum, effect on both gram positive and gram negative bacteria 2.Used against Pseudomonas 3.Can penetrate blood brain barrier, good for meningitis treatment |
What is the example of the 5th Cephalosporins? | Ceftobiprole |
Why Ceftobiprole is powerful? | 1.Potent antimicrobial activity against Pseudmonas, MRSAand also VRE 2.But still under clinical trial |
What are the 3 cell wall inhibitors antibiotics? | 1.Penicillins 2.Cephalosporins 3.Carbapenems |
Among the cell wall inhibitors, which one has the broadest antibacterial spectrum (gram positive and gram negative)? | Carbapenems |
Which enzyme will lead to resistance of Carbapenen | Carbapenemase |
What is the example of Carbapenemase? | New Delhi metallo-β-lactamase (NDM-1) |
What is the beta-lactamase inhibitor antibiotics? | Clavulanic acid |
What is the example of cell wall inhibitor antibiotics and why? | Vancomycin inhibits peptidoglycan synthesis |
What is most effect antibiotics against MRSA? | Vancomycin |
What are the examples of Nucleic acid synthesis inhibitor antibiotics? | Fluoroquinolones: Ofloxacin, Ciprofloxacin, Levofloxacin, moxifloxacin |
What is the mechanism of fluoroquinolones? | 1.Inhibit DNA gyrase and topoisomerase IV which is responsible for DNA replication and unwinding. 2.Lead to termination of chromosome replication |
What _____% Neisseria gonorrhoeae is resistant to fluoroquinolones? | 50 |
What are the examples of Anti-protein Synthetic Agent? | 1.Aminoglycosides 2.Marcolides 3.Clindamycin 4.Oxazolidinones |
What are the examples of aminoglycosides? | Streptomycin, Gentamicin, Tobramycin |
What is the mechanism of aminoglycosides? | 1.Bactericidal to aerobicGram negatives and S.aureus 2.Bind irreversibly to 30S ribosomal subunits 3.Cause misread of genetic code 4.Produce non-sense protein |
What are the examples of Macrolides? | Erythromycin, Azithromycin, clarithromycin |
What is the mechanisms of macrolides? | 1.Bacteriostatic to Gram positives and Haemophilus influenzae 2.Bind reversibly to 50S ribosomal subunits 3.Block the elongation |
What is the mechanism of Clindamycin? | 1.Bacteriostatic to Gram positive cocci and anaerobic Gram negative 2.Bind reversibly to 50S ribosomal subunits |
What is the example of Oxazolidinones? | Linezolid |
What is the mechanisms of Oxazolidinones? | 1.Bacteriostatic to aerobic and anaerobicGram positive bacteria 2.Preventing the formation of the initiation complex 3.By reversibly binding to 50S ribosomal subunits |
Oxazolidinones is approved to treat A and B? | Vancomycin Resistant Enterococci and MRSA |
What are the examples of Inhibition of general metabolic pathway? | Cotrimoxazole |
What are the examples of Cotrimoxazole? | Sulphonamidesand Trimethoprim |
What is the mechanism of Cotrimoxazole? | Block folate metabolic pathway-needed for purine and pyrimidine formation |
What are the three interaction of antibiotics and example pairs? | 1.Additive 2.Synergistive (Cephalosporin / penicillin + Clavulanic acid) 3.Antagonistic (Erythromycin and Clindamycin) |