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62 Cards in this Set
- Front
- Back
substance produced by bacteria to kill other bacteria
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bacteriocin
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bacterial cell walls are composed of a polymer of ___ and ____ in ___ linkage
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NAG and NAM in Beta-1 linkage
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5 targets of Antibiotics
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cell wall
bacterial ribosomes (70S) Nucelic Acid synthesis cell membranes intermediary metabolism |
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Cytoplasmic Portion of Cell Wall Synthesis: ____ converted to ____, then this king of amino acid is added: __ amino acids
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NAG to NAM
D sugars added--> important b/c humans use L amino acids |
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Antibiotic that prevents Dala--Dala formation in cytoplasm, thus preventing the cytoplasmic step in cell wall synthesis
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Cycloserine
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Carrier that binds UDP-NAM to UDP-NAG and transports NAM-NAG across membrane for 2nd phase of bacterial cell wall synthesis
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C55 isoprenoid alcohol (C55-PP)
moves across membrane in this form: C55-P-P-NAM-NAG |
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ANtibiotic that prevents membrane phase of cell wall synthesis by targeting this step: dephosphorylation of C55-PP for attachment of NAM
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Bacitracin
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Antibiotics that prevent cross-bridge formation in cell wall by inhibiting the transpeptidase that performs the cross-bridging between Llys of one aa chain to Dala of neighboring chain
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Penicillin and Cephalosporin
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Antibiotic that prevents cell wall cross-bridge formation by binding the substrate (the Dala)
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Vancomycin
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3 things that Penicillins require in a bacterial cell in order to operate
all are characteristics of growing cells |
transpeptidases
PBPs (penicillin binding proteins) Autolytic Enzyme system |
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Beta-Lactamase
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enzyme that many bacteria, especially Staph. aureus, produce in order to become Pencillin resistant by targeting the antibiotic's Beta-Lactam ring
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Which 3 bacteria are known to alter their PBPs and what does this accomplish (for them)?
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Strep. pneumoniae
Neisseria gonorrheae MRSA It renders them Penicillin resistant. |
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Penicillin G and Penicillin V
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group of Penicillins that are good against gram + cocci (like Strep. pyogenes or Arcanobacterium haemlyticum)
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2nd group of Pencillins adds a bulky side group for use against what type of bacteria?
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Gram + Cocci that produce Beta-Lactamase (i.e. Streptococcus spp)
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What penicillins fall into the 2nd group (i.e. those that have a bulky side group for counter-resistance to beta-lactamase producing bacteria)?
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Ordinary Men Never Take 2nds
Oxacillins (Cloxacillin, Dicloxacillin, Flucloxacillin--CDF) Methicillin Nafcillin Temocillin |
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What type of bacteria were the 3rd group of Penicillins designed to target with their amino acid side groups?
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the aa side group makes them more hydrophobic as as to pass through the outer lipid membrane of gram - bacteria
Designed to target gram- but also useful against gram+ bacteria |
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Why would you pair a 3rd group Penicillin with Calvulinic acid or Sulbactam?
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3rd group Pencillins are not Beta-Lactamase resistant, so in order to combat a bacteria with beta-lactamase, they must be paired with a Beta-Lactamase scavenger
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The 4th group of Penicillins are resistant to Beta Lactamase and are effective against Pseudomonas, but are not very effective against Gram +s. They include:
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Carbenicillin, Piperacillin, Ticeracillin
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Cephams were made for people who are allergic to Penicillin. These beta-lactams are called what?
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Cephalosporins
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Subsequent generations of Cephalosporins are improved in what 3 ways?
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Better gram - coverage
better CSF penetration More resistance to beta-lactamase |
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1st generation cephalosporins
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all begin with "Ceph" except Cefazolin, with "Cef" being close enough
Cefazolin Cephalothin |
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2nd generation cephalosporins include:
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ceFOXitin and ceFONICId
"Her 2nd foncy was fox fur" |
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3rd generation cephalosporins show excellent CSF penetration but, although they are broad spectrum, have only fair Gram + coverage. They include:
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ceFIXIME and MOxalactam
"Fix e me Mo" plus 2 with added pseudomonas coverage: cefOPERAzone and cefTAZidime "don't want TAZ OPERAting on you"--> Taz is the psuedomonas of Looney Tunes |
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Cefepime
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4th generation cephalosporin: useul agains gram + and gram -, used for UTIs and severe penumonias
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Monobactams
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a class of beta lactam antibiotics that includes Aztreonam--> targets cell walls of Enterobacteria
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Theinamycins
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class of beta-lactam antibiotics that targets cell walls and has a very broad spectrum (gram + and -)
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Imipenem
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a thienamycin, possibly the braodest spectrum antibiotic--> use when you don't know what the bacteria is
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2 antibiotics that target the cell wall but are not beta-lactams and are therefore resistant to beta-lactamase
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Vancomycin and Teicoplanin
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How do bacteria establish resistance to Vancomycin and Teicoplanin?
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they place a lactyl group in place of second Dala at the end of an aa chain--> the antibiotics don't recognize lactyl and therefore cannot prevent cross-bridge form'n
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Oxazolidinone (Zyvox)
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antibiotic that prevents protein synthesis by preventing assembly of 50S and 30S ribosomal subunits
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What do Aminoglycosides inhibit?
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bind S12 on the 30S subunit to prevent protein synthesis
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Which Penicillins are Beta-Lactamase resistant, and how can bacteria become resistant to these abx as well?
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Remember: Penicillins end in "cillin"
Oxacillins (CDF--Cloxacillin, Dicloxacillin, Flucoxacillin), Methicillin, Nafcillin, Temocillin "Ordiary Men Never Take 2nds" Bacteria establish R to these by altering PBPs (penicillin binding proteins) such as transpeptidase and surface proteins |
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Why should bacteriostatic drugs not be given in combination with Penicillin?
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Penicillin targets things in actively growing cells, especially the autolytic system
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Name one advantage and one disadvantage of cephalosporins compared to Penicillins.
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Pro: cephalosporins are largely resistant to beta-lactamase
Con: most cephalosporins can't cross the BBB |
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Name 2 classes of Beta-Lactams
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Penams = Penicillins
Cephems = Cephalosporins Both target transpeptidases in order to destabilize the bacterial cell wall. |
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What are the constituents of Augmenten?
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Ampicillin (gram + spectrum Penicillin) + a Beta-Lactamase scavenger (calvulonic acid or sulbactam)
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What do aminoglycosides target? Are they bactericidal or bacteriostatic?
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bind to the 30S ribosomal subunit to prevent protein synthesis
Most useful against gram - Bactericidal |
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Aminoglycosides include:
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GNATS are full of cin--and are small enough to inhibit small (30S) ribosomal subunit
Gentmycin Netilmicin Amikacin Tobramycin Streptomycin |
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Streptomycin Monosomes
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Streptomycin binds the 30S subunit, causing mRNA dissociation then reassociation--> these structures are irreversibly frozen
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How might a bacteria become resistant to Streptomycin?
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mutation in S12 protein (=binding site on 30S subunit)
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What do Tetracyclines target?
Bacteriocidal or static? |
prevent tRNA binding in the 30S subunit
The are bacteriostatic--but they have a very wide spectrum complex with Mg++ to bind ribosome |
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Tetracyclines include:
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Note: they end in "-cyclene"
Doxycyclene and Minocyclene |
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How might a bacteria become resistant to Tetracyclines?
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efflux--they develop a mechanism to pump the antibiotic out of the cell
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What antibiotics target the 30S subunit and thus protein synthesis?
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The GT ANTS are really small.
"the great ants are really small" Gentomycin Tobramycin AMikacin Netilmicin Tetracyline group Streptomycin |
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What abx target the 50S subunit and thus protein synthesis?
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"it onl takes 50 SECCC of cin with alchohol"
Erythromycin Clarithromycin (bactericidal) Clindamycin (good for anaerobes) Chloramphenicol |
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How do bacteria become R to abx that target the 50S subunit?
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they alter the ribosome or, for chloramphenicol resistance, they acetylate the antibiotic
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Abx that impede nucleic acid replication include:
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Rifampin
Metronidazole Quinalones (Naldixic Acid, Norfloxacin, Ciprofloxacin=>"CNN") MNopQR Metronidazole Quinalones Rifampin all OPpose Nucleic acid replication or think: Nucleicacids-- Metronidazole, Quinalones, Rifampin are your OPtions |
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How does Rifampin work?
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impedes nucleic acid synthesis by binding the beta subunit of RNA Pol
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What does Chloramphenicol target and what is a major risk associated with its use?
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it targets the 50S subunit to prevent protein synthesis
side-effects include Aplastic Anemia |
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What bacteria is Rifampin used against?
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TB, leprosy, most gram +, Legionella spp.; Haemophilus spp.
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How does Metronidazole work?
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it breaks down into free radicals upon entry into bacterial cell to impede nuceic acid synthesis
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What organisms does metronidazole target?
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anaerobes (no enzymes for processing O2) and protozoa
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How do Quinolones work?
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inhibit DNA gyrase/helicase to inhibit nucleic acid synthesis
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Name the Quinalones and what organisms they are used against.
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Naldixic Acid -- gram +
Norfloxacin - gm+, pseudomonas Ciprofloxacin- gm+, pseudomonas |
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Abx that target bacterial cell outer membranes (thus gram- only) include:
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Polymyxin E--forms pores in membrane that caues leakage
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Polymyxin E is useful against what bacteria?
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Pseudomonas
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What abx are syngergistic with Polymyxin E?
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Streptomycin and Penicillins
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What group of antifungals targets the cell membrane and how?
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Polyenes--binds or inhibits ergosterol
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What antifungals are members of the Polyene group?
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Nystatin and Amphotericin B
Azoles (except Metronidazole, an abx that inhibits nucleic acid synthesis) are more mild and include: imidazole triazole |
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What abx target intermediary metabolism?
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ASIST in killing bacteria
Aminosaliclic acid Sulphonomides Isoniazid Sulfones Trimethoprim 3 kick paba's ASS: aminosalicyclic acid (TB), Sulfone (leprosy), & Sulfonamides (synergy w Trimethoprim for UTIs) Isoniazid--inhibits cell wall form'n in acid fast bacteria (TB) Trimethoprim (UTIs) |
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What abx inhibit folate synthesis by competitively inhibiting PABA?
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they kick paba's ASS
Aminosalicylic acid--TB Sulphonomides--utis, gm+ and - Sulfones-- leprosy R by upregulating paba |
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What antibiotic inhibits folate synthesis by inhibiting dihydrofolate reductase, and is synergystic with Sulphonos?
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trimethoprim-- tx for UTIs
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