Chapter 33: Bacterial Infections: DNA replication, Transcription, Translation

Question 1

-Floxacins MOA and clinical application

Answer 1

These are the Quinolones

Inhibit bacterial type II topoisomerases …inhibits DNA gyrase in Gram -

Gram Negative Infections

Question 2

How do bacteria gain resistance to Quinolones (floxacins)?

Answer 2

Chromosomal mutations in genes for Type II topoisomerase

Alterations in membrane porins and efflux pumps

Question 3

Rifabutin and Rifampin MOA?

Answer 3

Targets the B subunit of bacterial RNA polymerase - forming a stable complex with this prevents the elongation phase of transcription

BOTTOM LINE: inhibit transcription

RRRifampin –> RRRRna polymerase –> RRRRed blood Tb

Question 4

Should Rifampin be used as a single unit?

Answer 4

No because resistance develops quickly

Question 5

You should NOT use rifabutin with which other drug?

Answer 5

clarithromycin

Question 6

What is the major use of rifabutin and rifampin?

Answer 6

Mycobacterial infections including tuberculosis

Question 7

What class of drugs would you use for SERIOUS gram negative infections? Nemonic? MOA?

Answer 7

Aminoglycosides

end in “Mycin”

Bind to 16S rRNA of the 30S ribosomal subunit and mess with protein synthesis…causes mRNA misreading that will basically KILL the cell

Question 8

Are aminoglycosides (-mycins) bactericidal or bacteriostatic?

Answer 8

BACTERICIDAL…THEY KILL THAT SHIZ

Question 9

What are the most widely used aminoglycosides? (3)

Answer 9

Amikacin
Gentamicin
Tobramycin

Question 10

What drugs used to treat gram negative infections have the adverse effect of ototoxicity?

Answer 10

aminoglycosides can cause ototoxicity (damage to hair cells)

Question 11

Bactericidal vs. Bacteriostatic?

Answer 11

Kill vs. Stop Reproduction

Question 12

What antibiotics could you use with Aminogylcosides?

Answer 12

B Lactam antibiotics

Question 13

Three Mechanisms that cause Resistance to Aminoglycosides?

Answer 13

1) plasmid encoded production of enzymes that inactive aminoglycoside
2) Alteration of porins so that drug entry is impaired
3) Mutation of the drug’s target on the 30S subunit

Question 14

Spectinomycin targets the 30S subunit and is used as alternative therapy for __?

Answer 14

Gonorrhea

Question 15

Tetracyclines (-cyclines) target the 30S subunit and can be used to treat –?

Answer 15

corynebacterium acnes
h. influenzae
vibrio cholerae
spirochetes
mycoplasma pneumoniae
chlamydia

Question 16

Which tetracycline can be used for malaria prophylaxis and for people with KIDNEY issues?

Answer 16

Doxycycline

Question 17

Which class of antimicrobial drugs can cause a bulging fontanelle, discoloration and hypoplasia of teeth, and growth stunting?

Answer 17

tetracyclines

Question 18

Children under 8 should not be given which antimicrobials?

Answer 18

tetracyclines

Question 19

If prescribing tetracyclines to a patient, what directions must you give about taking the medication?

Answer 19

Take these on an empty stomach because calcium products can interfere with absorption

Question 20

Patient has skin or subcutaneous infection, complicated abdominal infection, or community acquired pneumonia. What bacteriostatic 30S subunit targetting drug would you prescribe?

Answer 20

Tigecycline

Question 21

What is gray baby syndrome and what drug has a major risk of this?

Answer 21

Vomiting, flaccidity, respiratory distress, metabolic acidosis in newborns

Chloramphenicol

Question 22

Which drug targetting the 50S subunit can be used for tricky resistance strains because of increased affinity for 50S?

Answer 22

Telithromycin

Question 23

Erythromycin MOA

Answer 23

binds to 50S ribosomal subunit - bacteriostatic

Question 24

How would you treat Legionella pneumophila?

Answer 24

erythromycin

Question 25

Clarithromycin has increased activity against…

Answer 25

h influenzae

Question 26

Azithromycin has increased activity against ….

Answer 26

h influenzae and moraxella catarrhalis

Question 27

Clindamycin targets the 50S subunit and blocks peptide bond formation, but is associated with the overgrowth of ____ that can lead to colitis?

Answer 27

C Diff

Question 28

What is the only class of drugs that target 50S subunit and are Bactericidal?

Answer 28

Streptogramins - dalfopristin/quinupristin

Pristin–> pristine–> completely KILL

Question 29

Dalfopristin/quinupristin use? Do not use with what?

Answer 29

skin infections due to staph aureus or strep pyogenes

vancomycin resistant enteroccous faecium VREF

SSRIs because serotonin syndrome

Question 30

What drug targets 50S subunit and is used against Gram POSITIVE infections?

Answer 30

Linezolid

Question 31

What drug would you use to treat impetigo due to MRSA or Strep pyogenes?

Answer 31

Retapamulin (50S)