07_Antibiotic Essential Comparisons_Jonathan and Yinka Flashcards
Of the Antimetabolites what microorganisms are halted or killed by…
Sulfanilamide?
Trimethoprim?
Isoniazid?
Sulfanilamide»_space; wide range of bacteria and protozoa
Trimethoprim»_space; wide range of bacteria and protozoa
Isoniazid»_space; M. tuberculosis (mycobacteria)
Note: Sulfanilamide and Trimethoprim are static.
Isoniazid is cidal
Of the penicillins, what microorganisms are killed by... Penicillin G and Penicillin V Ampicillin and Amoxicillin Tricarcillin Piperacillin Methicillin and Oxacillin
Penicillin G and Penicillin V»_space; G+ and some G- cocci (meningitis and ypphilis) (note V is acid stable)
Ampicillin and Amoxicillin»_space; G- enteric and most G+ (note ampicilin is acid stable)
Tricarcillin»_space; G- bacilli, P. Aeruginosa, some G-
Piperacillin»_space; G- bacilli, P. Aeruginosa, anaerobes, and some G +
Methicillin and Oxacillin»_space; some G+ (note Oxacillin is acid stable)
Of the Cephalosporins, what microorganisms are killed by... Cefazolin? Cefuroxime? Ceftriaxone? Ceftazidime?
Cefazolin»_space; G+ and some G- enteric
Cefuroxime»_space; more G- and less G+
Ceftriaxone »_space; broad G- and high penetration to blood brain barrier
Ceftazidime»_space; broad G- and P. Aeruginosa
Of the B-lactams, what microorganisms are killed by…
Aztreonam?
Imipenem?
Aztreonam»_space; aerobic G- and P. aeruginosa
Imipenem»_space; broadest antimicrobial spectrum
Of the Glycopeptides, what microorganisms are killed by…
Vancomycin?
Cycloserine?
Bacitracin?
Vancomycin»_space; G+ multiply resistent enterococcus and MRSA
Cycloserine»_space; M. Tuberculosis (toxic, so 2ndary choice only)
Bacitracin»_space; G+ (toxic, topical)
What microorganisms are killed by Polymyxin B?
G- enteric and Pseudomonas
Of the Aminogycosides, what microorganisms are killed by…
Streptomycin?
Gentamycin?
Streptomycin»_space; M. Tuberculosis
Gentamycin»_space; doesn’t say
Of the Tetracyclines, what microoganisms are halted by…
Doxycycline?
Tigecycline?
Doxycycline and Tigecycline»_space; are affective against a broad spectrum of microorganisms including mycoplasma, rickettsia, chlamydia.
Note: Tigecycline is the most potent tetracycline. It means business.
Of the 50s inhibitors, what microorganisms are halted by... Erythromycin? Azithromycin? Chloramphenicol? Clindamycin? Sreptogramins?
Erythromycin»_space; G+ similar to penicillin, mycoplasma, and chlamydia.
Azithromycin»_space; broader spectrum than erythromycin (has long half life and high concentration at site of infection due to penetration of macrophages)
Chloramphenicol»_space; some anaerobes, B. fragilis
Clindamycin»_space; G+ moderate anaerobes
Sreptogramins»_space; MRSA and VREF
What microorganism is halted by the Oxazolidinone: Linezolid aka Zyyox?
G+
VREF
MRSA
What microorganism is halted (low concentration) or killed (high concentration) by Mupirocin?
MRSA, especially nasal MRSA
Of the DNA Replication Inhibitors, what microorganisms are killed by…
Ciprofloxacin and Moxifloxacin (Quinolones)?
Metronidazole (Nitroimidazole)?
Ciprofloxacin and Moxifloxacin (Quinolones)»_space; G- enteric baccili, some G+, and P. aeruginosa
Metronidazole (Nitroimidazole)»_space; Anaerobic (Bacteroides) and Protozoa (trichomoniasis and amebiasis)
Of the RNA synthesis inhibitors, what microorganism is killed by Rifampin?
Broad spectrum
Other antibiotics not otherwise classified that halt or kill Tuberculosis are?
Ethambutol (static)
Pyrazinamide (cidal)
Of the antifungals whic are cidal and which are static... Amphotericin B (polyene) Nystatin (polyene) Fluconazole & Ketoconazole (azole) Caspofungin (echinocadin) Flucytosine
Amphotericin B (polyene) >> cidal Nystatin (polyene) >> usually static, cidal at high doses Fluconazole & Ketoconazole (azole) >> static Caspofungin (echinocadin) >> cidal Flucytosine >> static and cidal
Of the antifungals, what microorganisms are halted or killed by…
Fluconazole & Ketoconazole
Caspofungin
Fluconazole & Ketoconazole»_space; oral cadidiasis aka thrush, mycoses, tinea versicolor
Caspofungin»_space; aspergillus candida
What are the contraindications of... Isoniazid? Penicillins? Vancomycin? Cycloserine? Bacitracin? Polymyxin B? Streptomycin? Gentamycin? Tetracycline & Doxycycline? Tigecycline? Chloramphenicol? Amphotericin B? Nystatin? Fluconazole & Ketoconazole?
isoniazid»_space; Liver and neurotoxic
Penicillins»_space; allergy
Vancomycin»_space; CN VII and renal toxic
Cycloserine»_space; toxic
Bacitracin»_space; toxic
Polymyxin B»_space; toxic when systemic
Streptomycin and Gentamycin»_space; CN VIII and renal toxic
Tetracycline, Doxycycline, and Tigecycline»_space; changes in GI flora and diarrhea
Chloramphenicol»_space; Lethal, aplastic anemia (rare) => not widely used
Amphotericin B»_space; toxic but used systemically
Nystatin»_space; very toxic
Fluconazole & Ketoconazole»_space; hepatotoxic orally
What is the mechanism for…
Sulfanilamide?
Trimethoprim?
Isoniazid?
Sulfanilamide»_space; competitively inhibits PABA in folic acid production
Trimethoprim»_space; inhibits DHF reductase
Isoniazid»_space; interpheres with mycolic acid synthesis
What is the mechanism for Penicillins, Cephalosporins, and B-lactams?
Binds to an inactivates PBP (transpeptidase responsible for peptidoglycan cross-linking)
Requires growth conditions
Uncouples control of autolysins
Of the Glycopeptides, what is the mechanism for…
Vancomycin?
Cycloserine?
Bacitracin?
Vancomycin»_space; Binds to peptidoglycan precursors, May also permeabilize protoplasts and inhibit RNA synthesis
Cycloserine»_space; Inhibits D-ala conversions in cell wall formation
Bacitracin»_space; Inactivates phosphatase that regenerates active carrier lipid in murein (peptidoglycan) precursor synthesis
What is the mechansims for Polymyxin B?
Binds to LPS (negatively charged) then to cytoplasmic membrane phospholipids => membrane leakage
Of the Aminogycosides, what microorganisms are killed by…
Streptomycin»_space;
Gentamycin»_space;
both inhibit the 30S function
at high concentration, strep inhibits initiation complex
gentamycin binds to more than one ribosome protein, so it is not a single step inhibition
What is the mechanism for tetracyclines?
blocks 30S
Of the 50S inhibitors, what is the mechanism of... Erythromycin Azithromycin Chloramphenicol Clindamycin Sreptogramins Note the mechanisms are all similar
basically all block chain elongation
What is the mechanism of Oxazolidinones Linezolid (Zyvox)?
Inhibits tRNA translocation
Interacts with 16S RNA and 23S rRNA of both subunits
What is the mechanism on Mupirocin?
Binds isoleucyl-tRNA synthetase
Of the DNA Replication Inhibitors, what is the mechanism of…
Ciprofloxacin and Moxifloxacin (Quinolones)?
Metronidazole (Nitroimidazole)?
Ciprofloxacin and Moxifloxacin (Quinolones)»_space; Inhibits DNA gyrase
Metronidazole (Nitroimidazole)»_space; “Binds and fragments DNA
Reduced and activated by Ferredoxin
What is the mechanism of RNA Synthesis Inhibitor Rifampin?
Binds to β subunit of bacterial RNAp
What is the idiosyncratic mechanism requirement of Pyrazinamide?
Requires activity of Mycobacteria amidase
Of the anti-fugals what is the mechanism of... Amphotericin B and Nystatin? Fluconazole & Ketoconazole? Caspofungin? Flucytosine?
Amphotericin B and Nystatin»_space; “Bind to sterols in cell membrane => affect permeability, Selective for ergosterol (fungal/plant)”
Fluconazole & Ketoconazole»_space; “Inhibits ergosterol (cell membrane) synthesis via cP450 inhibition
Hyphae synthesis is also inhibited => easily phagocytosed
Caspofungin»_space; Inhibit glucan (cell wall) synthesis via glucan synthase
Flucytosine»_space; “Antimetabolite: replaces uracil => RNA synthesis
Also inhibits thymidylate synthetase => DNA synthesis
What are the static antibiotics and anitfungals?
Sulfanilamide
Trimethorprim
Tetracyclines
50s Inhibitors: Erythro, Azithro, Chloramphenicol, Clindamycin, Sreptogramins
Linezolid (Oxazolidinones)
Ethanbutol
Nystatin
