Test 2 Review Flashcards
Mycobacteria vaccine?
BCG aka Bacilli Calmete Guerin vaccine
-stimulates the cell mediated response (M. tuberculosis is largely intracellular)
Mycobacteria:
The live attenuated vaccine is made from….
M. Bovis (cow TB)
How is sputum decontaminated?
-NAOH will decontaminate but too much can kill mycobacteria
-NALC is a digestant and will liquify the sputum
What can be used on specimens contaminated with pseudomonas or proteus?
Zephiran-trisodium phosphate & oxalic acid
Preparation & Digestion of Sputum, what are the steps?
- Add NALC/NaOH
- Vortex, then let sit for 15 minutes
- Add buffer to stop reaction, then centrifuge at high speed
- Pour off supernatant & make smears; inoculate solid/liquid media
Target cell wall synthesis (binds to penicillin binding proteins [PBP])
· Blocks polymer cross linking
· Beta-lactams contain a beta-lactam ring
· Broad spectrum (can target gram – and gram +)
· Structurally similar to acyl-D-alanyl-D-alanine
Cell Wall Synthesis Inhibitors
anything ending with -cillin, or -penem or starts with ceph-
Beta-Lactams
The antibiotics that fall under Penicillin?
Penicillin G - Dicloxacillin
- Amoxicillin - Flucloxacillin
- Nafcillin - Carbenicillin
- Oxacillin - Ticarcillin
- Piperacillin
The antibiotics that fall under Cephalosporins?
- Cefazolin - Cephalexin
- Cefuroxime - Cefoxitin
- Ceftriaxone -ceftazidime
- Cefazoline
The antibiotics that fall under Carbapenems?
- Imipenem - Meropenem
What is the antibiotic that is an enzyme inhibitor?
Fosfomycin (inhibits enzyme at first step of cell wall synthesis)
What antibiotics fall under Glycopeptides/lipoglycopeptides?
- Vancomycin - teicoplanin
- Bacitracin
Example of monobactam bacteria?
Aztreonam
What are the classes of antibiotics that fall under “Cell Wall synthesis inhibitors” (Beta-Lactams)
-penicillin
-Cephalosporins
- Carbapenems
- Enzyme Inhibitor
- Glycopeptides/lipoglycopeptides
- Monobactam
Acts as detergents by interacting with the phospholipids
· Results in leakage of macromolecules from bacterial cells
· Also attacks human cell membranes causing toxicity issues (neuro & nephrotoxicity)
Polymyxin
Polymyxin is often combined with neomycin & ___________ as topical antimicrobial
Bacitracin
Binds cell wall & disrupts it (Gram POSITIVE)
· Inserts hydrophobic tail into membrane
Lipopeptides
What are the four main cell wall synthesis inhibitor antibiotic types?***
- Beta-lactams
- Enzyme inhibitors
- Glycopeptides/lipoglycopeptides
- Monobactam
What are the antibiotics that target the cytoplasm membrane?
Polymyxin B, collistin, Daptomycin
What are the four antibiotic types that target Nucleic acid synthesis?
- DNA gyrase and topoisomerases:
- Interacting with DNA
- RNA polymerase
- Folate Synthesis
Nucleic acid synthesis:
What are the antibiotics that target DNA gyrase and topoisomerase?
Quinolones ( —-floxacin (Fluroroquinolines) e.g. Ciprofloxacin, ofloxacin, lomefloxacin, sparfloxacin, Trofloxacin, Moxifloxacin, Gemifloxacin), Enoxacin, nalidixic acid).
Nucleic acid synthesis:
Example of antibiotic that causes loss of helical DNA structure?
Metronidazole
Nucleic acid synthesis:
Example of RNA polymerase antibiotic
Rifampin
Nucleic acid synthesis:
Examples of antibiotic that targets folate synthesis?
Sulfonamides, Trimethoprim
Antibiotics that target protein synthesis by either the ______ subunit or the _____ subunit.
50S, 30S
What are the antibiotics that target the 50S subunit?
a. Macrolides or ketolides (erythromycin, clarithromycin, azithromycin, roxithromycin), b. Licosamide (clindamycin), c. chloramphenicol, d. Oxazolidinones (linezolid, sutezolid, Eperezolid, Radezolid, Contezolid, Posizolid, Tedizoid, Depazolid), e. streptogramins (Quinupristin, dalfopristin, pritinamycin, virginamycin)
What are the antibiotics that target the 30S subunit?
Tetracyclines or Glycylglycines (derivatives of tetracyclines, e.g. Doxycycline, Tegecycline), Aminoglycosides (gentamicin, amikacin, tobramycin, neomycin, and streptomycin)
Common synergistic:
beta-lactam + aminoglycosides
What is used only for UTI?
Nitrofurantoin
What antibiotic is gram positive only?
Glycopeptides/lipoglycopeptides
Resistance to vancomycin by enterococcus by the vanA, vanB, vanC, vanD and vanE (vanA is the most common)
Monobactam
Aztreonam
Acts as detergents by interacting with the phospholipids
·Results in leakage of macromolecules from bacterial cells
Also attacks human cell membranes causing toxicity issues (neuro & nephrotoxicity)
Cyclic lipopeptides
Polymyxin B & Colistin
Polymyxin is often combined with neomycin & bacitracin as topical antimicrobial
Colistin was used for gram negative rod infections, but have severe renal toxicity (no longer used, unless it’s the last line of defense)
Polymyxin
Binds cell wall & disrupts it (Gram POSITIVE)
Inserts hydrophobic tail into membrane
Daptomycin
Daptomycin has potent activity against gram positive cocci
Treats MRSA and VRE (vancomycin resistant enterococcus)
Large size prevents it from penetrating gram negative membrane
Not good for respiratory infections; lung surfactant inactivates it
Lipopeptides
-Generally bacteriostatic, but can be bactericidal
-Binds to the 23s ribosomal RNA on the 50S ribosomal subunit
-Disrupts the growing peptide chain by preventing translocation
-Uptake difficulties with gram negative bacteria
50S Subunits:
Macrolides/Ketolides
50S Subunits:
Macrolides/Ketolides examples?
Erythromycin - Clarithromycin
Azithromycin - roxithromycin
Prevents elongation (interferes with peptidyl transfer)
Works against gram + and some anaerobic gram –
Increased c diff infections!!
50S Subunits:
Lacosamide
50S Subunits:
Lacosamide example?
Clindamycin
50S subunit:
-Inhibits peptidyl transferase
-Gram negative!
Chloramphenicol
50S subunit:
-Newer class
-Synthetic
-Binds the 23S ribosomal RNA of 50S subunit, prevents the formation of functional 70S initiation complex, preventing replication and translation
-No cross resistance with other drugs
-Gram positive & mycobacteria!
Oxazolidinones
50S subunit:
examples of Oxazolidinones?
Linezolid - sutezolid
Eperezolid - Radezolid
Contezolid - Posizolid
Tedizolid -Depazolid
50S subunit:
- Synergistic
-Dalfopristin binds to ribosomal 50S subunit changing the conformation - This increases the affinity of quinupristin which binds to the bacterial ribosome
-The double binding interrupts protein synthesis & blocks bacterial growth
Streptogramins
examples of Streptogramins?
Quinupristin - dalfopristin
Pristinamycin - virginiamycin
30S subunit:
Broad spectrum
Bacteriostatic
Incoming tRNA-AA complex cannot bind to ribosome
G+ & G- & intracellular pathogens
Cutaneous phototoxicity
Glycylglycines reversibly bind the 30S ribosomal subunit
Tetracyclines/Glycylglycines
30S subunit:
30S subunit:
30S subunit:
M. avium and _________ closely resemble each other.
M. intracellulare
-frequently called MIA
-distinction cannot be made by routine laboratory testing
-causes slowly progressing pulmonary infections
-High temps!!!!!
-water!
M. xenopi
-Burli ulcer (neglected tropical disease)
-causes scarring that can progress to the bone
-grows at lower temps
M. ulcerans
-skin infections but they can disseminate
-requires hemin! (sub. culture chocolate plate)
M. heamophilus
-Runyon group that grows in less than 7 days.
-ubiquitous
-disease in immunocompromised persons
Runyon group 4
examples of Runyon group 4 organisms?
-M. fortuitum-
-M. chelonae
-M. abscessus
