Antibiotics--The Basics

Front 1

substance produced by bacteria to kill other bacteria

Back 1

bacteriocin

Front 2

bacterial cell walls are composed of a polymer of ___ and ____ in ___ linkage

Back 2

NAG and NAM in Beta-1 linkage

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5 targets of Antibiotics

Back 3

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

Front 5

Antibiotic that prevents Dala--Dala formation in cytoplasm, thus preventing the cytoplasmic step in cell wall synthesis

Back 5

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

Back 6

C55 isoprenoid alcohol (C55-PP)

moves across membrane in this form: C55-P-P-NAM-NAG

Front 7

ANtibiotic that prevents membrane phase of cell wall synthesis by targeting this step: dephosphorylation of C55-PP for attachment of NAM

Back 7

Bacitracin

Front 8

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

Back 8

Penicillin and Cephalosporin

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Antibiotic that prevents cell wall cross-bridge formation by binding the substrate (the Dala)

Back 9

Vancomycin

Front 10

3 things that Penicillins require in a bacterial cell in order to operate

all are characteristics of growing cells

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transpeptidases
PBPs (penicillin binding proteins)
Autolytic Enzyme system

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Beta-Lactamase

Back 11

enzyme that many bacteria, especially Staph. aureus, produce in order to become Pencillin resistant by targeting the antibiotic's Beta-Lactam ring

Front 12

Which 3 bacteria are known to alter their PBPs and what does this accomplish (for them)?

Back 12

Strep. pneumoniae
Neisseria gonorrheae
MRSA

It renders them Penicillin resistant.

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Penicillin G and Penicillin V

Back 13

group of Penicillins that are good against gram + cocci (like Strep. pyogenes or Arcanobacterium haemlyticum)

Front 14

2nd group of Pencillins adds a bulky side group for use against what type of bacteria?

Back 14

Gram + Cocci that produce Beta-Lactamase (i.e. Streptococcus spp)

Front 15

What penicillins fall into the 2nd group (i.e. those that have a bulky side group for counter-resistance to beta-lactamase producing bacteria)?

Back 15

Ordinary Men Never Take 2nds

Oxacillins (Cloxacillin, Dicloxacillin, Flucloxacillin--CDF)
Methicillin
Nafcillin
Temocillin

Front 16

What type of bacteria were the 3rd group of Penicillins designed to target with their amino acid side groups?

Back 16

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

Front 17

Why would you pair a 3rd group Penicillin with Calvulinic acid or Sulbactam?

Back 17

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

Front 18

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:

Back 18

Carbenicillin, Piperacillin, Ticeracillin

Front 19

Cephams were made for people who are allergic to Penicillin. These beta-lactams are called what?

Back 19

Cephalosporins

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Subsequent generations of Cephalosporins are improved in what 3 ways?

Back 20

Better gram - coverage
better CSF penetration
More resistance to beta-lactamase

Front 21

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"

Front 23

3rd generation cephalosporins show excellent CSF penetration but, although they are broad spectrum, have only fair Gram + coverage. They include:

Back 23

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

Front 24

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

Front 28

2 antibiotics that target the cell wall but are not beta-lactams and are therefore resistant to beta-lactamase

Back 28

Vancomycin and Teicoplanin

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How do bacteria establish resistance to Vancomycin and Teicoplanin?

Back 29

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

Front 30

Oxazolidinone (Zyvox)

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antibiotic that prevents protein synthesis by preventing assembly of 50S and 30S ribosomal subunits

Front 31

What do Aminoglycosides inhibit?

Back 31

bind S12 on the 30S subunit to prevent protein synthesis

Front 32

Which Penicillins are Beta-Lactamase resistant, and how can bacteria become resistant to these abx as well?

Back 32

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

Front 33

Why should bacteriostatic drugs not be given in combination with Penicillin?

Back 33

Penicillin targets things in actively growing cells, especially the autolytic system

Front 34

Name one advantage and one disadvantage of cephalosporins compared to Penicillins.

Back 34

Pro: cephalosporins are largely resistant to beta-lactamase

Con: most cephalosporins can't cross the BBB

Front 35

Name 2 classes of Beta-Lactams

Back 35

Penams = Penicillins
Cephems = Cephalosporins

Both target transpeptidases in order to destabilize the bacterial cell wall.

Front 36

What are the constituents of Augmenten?

Back 36

Ampicillin (gram + spectrum Penicillin) + a Beta-Lactamase scavenger (calvulonic acid or sulbactam)

Front 37

What do aminoglycosides target? Are they bactericidal or bacteriostatic?

Back 37

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

Front 40

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?

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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

Front 44

What antibiotics target the 30S subunit and thus protein synthesis?

Back 44

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?

Back 45

"it onl takes 50 SECCC of cin with alchohol"
Erythromycin
Clarithromycin (bactericidal)
Clindamycin (good for anaerobes)
Chloramphenicol

Front 46

How do bacteria become R to abx that target the 50S subunit?

Back 46

they alter the ribosome or, for chloramphenicol resistance, they acetylate the antibiotic

Front 47

Abx that impede nucleic acid replication include:

Back 47

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

Front 48

How does Rifampin work?

Back 48

impedes nucleic acid synthesis by binding the beta subunit of RNA Pol

Front 49

What does Chloramphenicol target and what is a major risk associated with its use?

Back 49

it targets the 50S subunit to prevent protein synthesis

side-effects include Aplastic Anemia

Front 50

What bacteria is Rifampin used against?

Back 50

TB, leprosy, most gram +, Legionella spp.; Haemophilus spp.

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How does Metronidazole work?

Back 51

it breaks down into free radicals upon entry into bacterial cell to impede nuceic acid synthesis

Front 52

What organisms does metronidazole target?

Back 52

anaerobes (no enzymes for processing O2) and protozoa

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How do Quinolones work?

Back 53

inhibit DNA gyrase/helicase to inhibit nucleic acid synthesis

Front 54

Name the Quinalones and what organisms they are used against.

Back 54

Naldixic Acid -- gram +
Norfloxacin - gm+, pseudomonas
Ciprofloxacin- gm+, pseudomonas

Front 55

Abx that target bacterial cell outer membranes (thus gram- only) include:

Back 55

Polymyxin E--forms pores in membrane that caues leakage

Front 56

Polymyxin E is useful against what bacteria?

Back 56

Pseudomonas

Front 57

What abx are syngergistic with Polymyxin E?

Back 57

Streptomycin and Penicillins

Front 58

What group of antifungals targets the cell membrane and how?

Back 58

Polyenes--binds or inhibits ergosterol

Front 59

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?

Back 60

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)

Front 61

What abx inhibit folate synthesis by competitively inhibiting PABA?

Back 61

they kick paba's ASS
Aminosalicylic acid--TB
Sulphonomides--utis, gm+ and -
Sulfones-- leprosy

R by upregulating paba

Front 62

What antibiotic inhibits folate synthesis by inhibiting dihydrofolate reductase, and is synergystic with Sulphonos?

Back 62

trimethoprim-- tx for UTIs