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89 Cards in this Set
- Front
- Back
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MIC?
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minimal inhibitory concentration
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Frequency of bacterial mutation:
1 mutation per ___ cells |
1 to 10^16 cells
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Broad spectrum antibiotic therapy commonly causes what female problem
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vaginitis
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What pt should not receive bacteriostatic drugs?
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immunosuppressed
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3 Adaptations that lead to resistance
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lipopolysaccharide coat changes to alter uptake
transport system is altered to remove drug from cell metabolism changes to bypass the effect of the drug |
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What entities code for enzymes that inactivate antibiotics?
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plasmids and transposons
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Most common complaints about antibiotics
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Diarrhea and nausea
bad taste |
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Best way to pick a drug?
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Culture (and sensitivity)
C&S |
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Inhibitors of cell wall synthesis
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ß-lactams
Polypeptides |
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Protein synthesis inhibitors
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Aminoglycosides
Chloramphenicol Clindamycin Macrolides Ketolide Streptogramin Oxazolidanone Tetracyclines |
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Folate Antagonists
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Sulfonamides
Trimethoprim |
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Others
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Quinolones
Urinary tract antiseptics |
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Final step in synthesis of bacterial cell wall is a cross linking of adjacent peptidoglycan strands - this is called what?
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transpeptidation
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Penicillins and cephalosporins Structures are similar to what part of bacteria
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the terminal portion of the peptidoglycan strands
Result is bacteria with structurally weakened cell walls and death |
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All contain a ß lactam ring (4)
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Penicillins
Cephalosporins Carbapenems Monobactams (Aztreonam) |
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Most common mode of resistance to beta lactams is _______
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plasmid transfer of the genetic code for ß lactamase
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Specific ß lactamases
(2) |
Penicillinase
Cephalosporinase |
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ß lactamase inhibitors (3)
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Clavulanic acid
Sulbactam Tazobactam |
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3 penicillins
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Penicillin G
Penicillin V Benzathin pen G |
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Penicillinase Resistant (5)
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Methicillin
Cloxacillin Dicloxacillin Nafcillin (MnO3) Oxacillin |
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Aminopenicillins (2)
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Amoxicillin
Ampicillin |
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Spectrum of Penicillins
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narrow (gm-pos)
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spectrum of aminopenicillins
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broad (gm-pos and some gm-neg)
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Extended Spectrum penicillins (5)
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Azlocillin
Carbenicillin Mezlocillin Piperacillin Ticarcillin (Takes Care of Pseudomonas And Me!) |
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spectrum of extended spectrum penicillins
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extended (gm-neg -- rarely gm-pos
active against pseudomonas |
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Penicillins:
Most can only cross the blood brain barrier if it is _____ |
inflammed
(use in meningitis) |
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Generally, oral absorption of penicillins are
a) adequate b) poor c) good |
poor
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Penicillins are excreted by active tubular excretion which can be blocked by concurrent administration of _______
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probenecid (prolongs action)
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3 types of hypersensitivity rxns with penicillins
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Immediate
Accelerated Late |
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symptoms of immediate reaction
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pruritis,
paresthesia, wheezing, choking, fever, edema, urticaria |
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immediate rxn is mediated by what immunological entity?
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IgE
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possible outcomes of immediate reaction to penicillin
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hypotension, shock, death
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when do Accelerated reactions happen timewise?
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1-72 hrs
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Accelerated reactions Consist mainly of _____
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urticaria
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Late reaction:
More common with_______ |
semisynthetics
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Late reaction is mainly what problem?
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skin rashes
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time period of late reaction to penicillins
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72 hours - weeks after administration
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Penicillins: Adverse Reactions
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Serious skin reactions
Multiforme erythrema Stevens Johnson Syndrome TEN Toxic Epidermal Necrolysis (TEN) |
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Cephalosporins: First Generation (2)
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Cefazolin
Cephalexin |
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Spectrum of cephalosporins
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Narrow spectrum (similar to broad spectrum penicillins)
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Are cephalosporins Sensitive to ß lactamases?
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yes
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Cephalosporins: Second Generation (3)
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Cefaclor
Cefamandole Cefoxitin |
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Spectrum of second gen Cephalosporins
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Increased activity toward gram negative organisms
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Diff from 1st gen?
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Increased stability
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Cephalosporins: Third Generation (3)
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Cefotaxime
Ceftazidime Ceftriaxone |
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Spectrum of 3rd gen
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Broader spectrum than previous generations
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3rd gen diff from 1st and 2nd
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More resistant to ß lactamases
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Cephalosporins: Fourth Generation (2)
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Cefepime
Cefpirome |
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spectrum of 4th gen
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Gram positive and gram negative activity
Effective against Pseudomonas aeruginosa Also gram negative organisms with multiple drug resistance patterns |
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Which Cephalosporins penetrate the CNS?
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Third and some second generation drugs
(treat meningitis) |
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Cephalosporins used in the treatment and prophylaxis of infections in hospitalized patients
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Third generation
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Cephalosporins targeted at organisms with multiple-drug resistance
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Fourth generation
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Cephalosporins and bleeding: comment
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Can interfere with vitamin K (increased bleeding)
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Comment on allergies and cephalosporins and penicillins
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Some cross-allergy with penicillins
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Cephalosporins: do not drink alcohol with cephs.... why?
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Disulfiram-like reaction:
Block alcohol oxidation Acetaldehyde accumulates |
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Carbapenems (3)
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Imipenem
Ertapenem Meropenem |
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Carbapenems are administered how?
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All administered iv
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Imipenem is hydrolyzed by renal ______ in the kidney to a toxic metabolite (and has no antimicrobial activity)
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dipeptidase
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Why must cilastatin be administered with imipenem?
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Cilastatin inhibits dipeptidase so must be administered with imipenem
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______ is stable to dipeptidase -does not require coadministration of cilastatin
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Meropenem
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Monobactams (1)
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Aztreonam
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Spectrum of monobactams
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Narrow spectrum
Aerobic gram negative bacteria including Pseudomonas Ineffective against gram positive bacteria |
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monobactams ß lactamase sensitivity?
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Highly resistant to ß lactamases
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Non ß Lactam Drugs: Cell Wall Synthesis Inhibitors (5)
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Vancomycin and teicoplanin
Bacitracin Fosfomycin Daptomycin |
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How do Vancomycin and teicoplanin
Inhibit cell wall synthesis? |
by preventing polymerization of the linear peptidoglycans
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Spectrum of Vancomycin and teicoplanin
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Only effective against gram positive organisms
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Bad things about Vancomycin and teicoplanin
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Poorly absorbed orally
Dose related ototoxicity (tinnitus, high tone deafness, hearing loss) Red man syndrome |
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What drug is this?
Mixture of polypeptides that inhibit cell wall synthesis Binds to lipid carrier that transports cell wall precursors Used topically due to serious nephrotoxicity |
Bacitracin
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What drug is this?
Inhibits one of the first steps in the synthesis of peptidoglycan (enolpyruval transferase) Used for treatment of UTIs |
Fosfomycin
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What drug is this?
Binds to membrane of bacteria and causes depolarization Loss of membrane potential results in death |
Daptomycin
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What kind of drug is this?
Major route of resistance is blockade of drug from entering the cell |
Protein Synthesis Inhibitors
Require binding to intracellular protein (ribosomal subunit) so must enter the cell |
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Aminoglycosides (7)
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Kanamycin
Gentamicin Amikacin Neomycin Netilmicin Tobramycin Streptomycin |
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Spectrum of Aminoglycosides
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Broad spectrum antimicrobials but anerobic bacteria are generally resistant
Drug enters bacteria through oxygen dependent transport system Anerobes do not oxygen dependent metabolism |
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How are aminoglycosides administered?
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Poorly absorbed from GI tract
Most must be administered parenterally coadministration of penicillins |
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Why coadministration of penicillins with aminoglycosides?
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Usually require a transport mechanism or coadministration of penicillins
Penicillins create cell wall abnormalities that allow aminoglycosides to penetrate the cell |
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Bad things about aminoglycosides
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Narrow margin of safety
Ototoxicity -Cochlear (auditory) -Symptoms: tinnitus, deafness, high frequency hearing loss -Due to selective destruction of outer hair cells in organ of Corti -Vestibular (vertigo) Nephrotoxicity -Due to rapid uptake of drug by proximal tubular cells and subsequent death -Acute nephrotoxicity is reversible Neurotoxicity -Due to blockade of presynaptic release of acetylcholine at neuromuscular junction (some postsynaptic blockade can also occur) -Symptoms: weakness and respiratory depression |
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Tetracyclines (5)
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Tetracycline
Chlortetracycline Oxytetracycline Demeclocycline Minocycline - Acne in small white people DOXYCYCLINE |
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Can you use expired tetracyclines?
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no - degrades to renal toxic compound
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How do tetracyclines work?
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Accumulate in cytoplasm by an energy dependent transport system which is not present in mammalian cells
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How do bacteria get resistant to tetracyclines?
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Resistance occurs when bacteria mutate to prevent entry of the drug into the cell
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Spectrum of Tetracyclines
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Broad spectrum (gram positive and negative organisms, anerobes)
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Use tetracyclines to treat what specific diseases?
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Rickettsial diseases (Rocky Mountain spotted fever)
Chlamydial diseases Cholera Lyme disease (spirochetes) Mycoplasma pneumonia |
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Why not eat food with tetracycline?
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Form insoluble chelates with calcium, magnesium and other metals
Avoid antacids Does not occur with doxycyline and minocycline |
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Why is teetracycline not recommended in children and pregnancy?
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Deposited in teeth and bones
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why not sunbath with tetracycline?
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Photosensitivity
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Macrolides (5)
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Clarithromycin
Azithromycin Dirithromycin Erythromycin Troleandomycin |
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Macrolides treat what diseases?
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Mycoplasma infections
Pneumonia Legionnaires’ disease Chlamydial infections Diptheria Pertusis |
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most common side effect of macrolides?
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GI upset
motilin agonist |
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useful for macrolide resistance organisms
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Telithromycin
(Ketolides) |
