Antibacterial Agents Slide Set Ii:

Front 1

What are the different antibiotics covered in this lecture: 11

Back 1

-tetracyclines
-glycylcyclines (tigecycline)
-chloramphenicol
-oxazolidinones
-sulfonamides
-trimethoprim
-quinolones
-rifamycin
-metronidazole
-nitrofurantoin
-methenamine

Front 2

What is tetracycline mechanism of action?

Back 2

-inhibits protein synthesis by binding to ribosomes (bacteriostatic)

Front 3

What bacteria does it target?

Back 3

-staph, strep, gram negatives, anaerobes
-Rickettsiae, ehrlichia, mycoplasma, borrelia, pasteurella, brucella, yersinia, francisella, V. cholera, chlamydia, bacillus, plasmodium (malaria)

Front 4

What are adverse side effects of tetracyclines:

Back 4

GI upset
-minocycline: vertigo;
-demeclocycline; photosensitivity ;
-deposited in bone and teeth; discolored teeth;

Front 5

What does tetracycline do when treating pneumococcal meningitis:

Back 5

antagonizes penicillin

Front 6

What is tetracycline absorption decreased by and What form of tetracycline causes fanconi syndrome?

Back 6

-absorption decreased by divalent/trivalent cations (calcium, magnesium, iron, aluminum);
-fanconi syndrome from outdated/ expired tetracycline; degrades over time

Front 7

glycylcyclines (tigecycline): what is it a derivative of?

Back 7

-tetracycline (so same mech of action)

Front 8

What is benefit of glycylcycline (tigecycline) over tetracycline?

Back 8

increased spectrum of activity; active against many tetracyclien resistant gram positive bacteria (MRSA; streptococci, enterococci; gram neg. bacteria and anaerobes/ same adverse effects though

Front 9

What is the mech of action of chloramphenicol and why is it rarely used?

Back 9

-binds to 50S ribosome (also to mitochondrial ribosome)
-therefore not used b/c can cause grey baby syndrome (lower conjugation and lower excretion);

Front 10

What are other adverse side effects of chloramphenicol?

Back 10

-bone marrow; aplastic anemia (1/24,500 - 1/40,800): higher rate of leukemias in those that recover

Front 11

oxazolidinones: What is a synthetic compound of oxazolidinones?

Back 11

-Linezolid

Front 12

What is the mech of action of oxazolidinones? and what is a main adverse effect?

Back 12

inhibits protein synthesis!
-bacteriostatic against S. aureus and enterococci:
-bactericidal against S. pneumoniae
-adverse effect; Thrombocytopenia!

Front 13

What is sulfonamide similar in structure to? Therefore, what type of organism does it target?

Back 13

-similar in structure to para aminobenzoic acid (PABA) that is used to synthesize folate
-therefore susceptible organisms are thost that must synthesize their own folate
-bacteria and humans that used preformed folate are NOT affected!

Front 14

-What do substitutions at the amide result in? how specifically does the sulfonamide work?

Back 14

-substitutions result in compound more active that may affect absorption; solubility, GI tolerance
-competitively inhibits incorporation of PABA into dihydrofolic acid; microbial enzyme (dihydropteroate synthetase

Front 15

what bacteria does it cover/

Back 15

-gram positive and negative bacteria and nocardia; however many bacteria have developed resistance

Front 16

What do you use ot treat toxoplasmosis?

Back 16

-sulfadiazine + pyrimethamine

Front 17

what treats infected burns?

Back 17

silver sulfadiazine

Front 18

What are adverse effects of sulfonamides?

Back 18

-GI upset, WBC abnormalities, thrombocytopenia, rash, hypersensitivity, and death
-in newborns: kernicterus (sulfa displaces bilirubin from albumin)

Front 19

Trimethoprim: function: how much more potent than sulfa is it? where does it penetrate?

Back 19

-dihydrofolate reductase inhibitor (DHFR) inhibitor
-potentiates sulfonamide and 20-100x more potent than sulfa
-PENETRATES INTO PROSTRATE

Front 20

What is it used in combo with sulfa to treat?

Back 20

-pneumocystis jiroveci (formerly pneumocystis carinii); Stenotrophomonas; tropheryma whippelii)

Front 21

adverse effx of trimethroprim:

Back 21

-megaloblastic anemia, leukopenia, granulocytopenia

Front 22

Trimethoprim/ sulfa:

Back 22

sulfamethoxazole to TMP 800 mg - 160 mg (5:1):
-tmp/smx should not be used to treat group A strep pharyngitis since no eradicate streptococcus

Front 23

What are quinolones derivatives of and what structural difference do newer quinolones have/

Back 23

Derivative of nalidixic acid
-fluorine at position 6

Front 24

What do quinolones do? gram negative vs. gram positive

Back 24

-inhibit DNA synthesis
-GRAM NEGATIVES: primary target is topoisomerase II (DNA gyrase) ; introduces negative supercoils into the DNA
gram positives: primary target is topoisomerase IV;
-bactericidal

Front 25

-What types of quinolones target gram negative:

Back 25

-nalidixic acid, ciprofloxacin, norfloxacin, ofloxacin
-P. aeruginosa ciprofloxacin (increases resistance, however)

Front 26

-Is quinolone active against INtracellular bacteira/

Back 26

yes! chlamydia, mycoplasma, legionella, brucella!

Front 27

- What type of quinolone has improved gram positive activity?

Back 27

-moxifloxacin

Front 28

What are adverse side effects of quinolones?

Back 28

-seizures, rash, tendon rupture
-hypoglycemia (gatifloxacin)
-arthropathy in immature animals ;hence NOT given to children!

Front 29

Quinolones: What is absorption decreased by?

Back 29

-decreased by divalent cations (calcium, magnesium, iron, etc)

Front 30

What are two types of rifamycins and what types of compounds are they? what do they diffuse through? What is the primary mechanism of action

Back 30

-rifampin and rifabutin
-macrocyclic compounds soluble in organic solvents; diffuse through lipids
inhibit bacterial DNA dependent RNA polymerase

Front 31

What is rifamycin active against/

Back 31

activea gainst mycobacteira nd gram positive and gram negative bacterai;
mutational resistance rapidly develops; must be used in combo wiht other antibacterial agents:

Front 32

Rifabutin activity:

Back 32

MAI

Front 33

rifampin activity:

Back 33

M. tuberculosis.

Front 34

adverse effects of Rifamycin:

Back 34

-turns body fludis (urine, saliva, tears, seat); orange-red;
-rash and hepatotoxicity

Front 35

How does metronidazole work?

Back 35

-alters cell membrane electrochemical potential
-

Front 36

What types of things does metronidazole target?

Back 36

-anaerobic bacteria; bacteroides fragilis c. difficile; protozoa (Trich, giardia; disulfiram-like reaction)

Front 37

-How does nitrofurantoin work and what is it active against? What type of treatment is it NOT used for?

Back 37

-damages DNA, active against E. coli, enterococci;
-not for treatment of pyelonephritis or prostatitis!

Front 38

-What are the adverse effects of Nitrofurantoin?

Back 38

-hypersensitivity, rash, fever, chills, leukopenia, granulocytopenia, hemolytic anemia, cholestatic jaundice, hepatocellular damage, acute pneumonitis;
-long term use can lead to interstital pulmonary fibrosis

Front 39

Methenamine: what does it do?

Back 39

-urinary tract antiseptic
-releases formaldehyde at an acidic pH
-nearly all bacteria are susceptible
proteus and other urea splitting bacteria raise urinary pH!!!