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Flashcards in Misc. Abx Deck (36):
1

Although tetracyclines are cross-reactive, ____________ is resistant to this because it is in the tetracyclin derivative category known as ____________.

*Tigecycline - Glycylcylins

2

What classes of microbials can tetracyclines be used against? (list some of the major targets) What 2 general conditions are they commonly used to treat?

- Gram-pos aerobes (*MSSA) - Gram-neg aerobes - Anaerobes - bacteroides spp. - Misc. bacteria. - legionella, chlamydophila, chlamydia, mycoplasma, ureaplasma, rickettsia (sketchy) - Often used for STI infections and dz's caused by tick bites!

3

Does tigecyclin have a more or less broad spectrum of activity vs. tetracyclins? Which organism is tigecyline notably not active against?

- Broader * Pseudomonas

4

Besides being inactive vs. pseudomonas, what 2 other conditions does tigecycline NOT treat?

*UTIs and *bacteremia

5

*What type of meds are tetracyclines and glycylcyclines contraindicated with?

Di and tri-valent cations (they should even avoid dairy due to Ca2+) - Must separate administration by a few hours

6

What are the major serious side effects a/w tetracyclines/tigecycline?

- Severe N/V - Photosensitivity (should avoid sun)

7

What can occur if expired tetracyclines are prescribed?

Fanconi-like syndrome a/w renal failure

8

What drug acts synergistically w/sulfas?

Trimethoprim (also inhibits folate/purine synth pw but at a different enzyme--dihydrofolate reductase)

9

What is the precursor of purine synthesis? - How is it affected by purine synthesis pw inhibitors?

PABA - Builds up

10

What drugs are in the combination Bactrim?

Trimethoprim-Sulfamethoxazole (TMP-SMX)

11

Explain the target organisms (only) of the broad-spectrum antibiotic TMP-SMX (Bactrim).

gram-pos: *staph aureus (MRSA, CA-MRSA) Gram-neg: - Stenotrophomonas maltophilia. Other: - Pneumocystis carinii. Plus many more (broad spectrum)

12

When giving Bactrim, what lab level should be monitored and why?

CrCl (kidney function; eliminated partially by kidney)

13

*What are the (3) major clinical uses of TMP-SMX?

1. Acute, chronic, or recurrent UTIs 2. Acute or chronic bacterial prostatitis 3. Skin infections due to CA-MRSA

14

What are the major adverse effects a/w TMP-SMX/Bactrim?

- Leukopenia - Thrombocytopenia - Rash/hypersensitvity - Renal impairment (crystaluria)

15

Are dose adjustments required in renal failure when giving chloramphenicol?

No, metabolized by liver

16

*What 2 major adverse effects are the reason that chloramphenicol isn't available in the U.S.?

- Gray Baby Syndrome (resp failure, death) - Aplastic anemia (no RBC production)

17

What are the 2 urinary tract agents that we need to know?

- Nitrofurantoin - Methenamine

18

What is nitrofurantoin used for? What is methenamine used for?

- Nitrofurantoin: used solely for UTIs - Methenamine: used solely as prophylaxis for UTIs if they’ve had recurrent UTIs

19

Which of the enterobacteriacea are lactose fermenters and which are non-lactose fermenters? (All ferment glucose, oxidase negative, reduce nitrate, and use MacConkey)

- Lactose fermenters: E. coli, klebsiella, Enterobacter, Citrobacter, Serratia - Non-lactose fermenters: Salmonella, Shigella, Proteus, Yersinia

20

Distinguish the characteristics of the 5 types of E. coli.

o Enterotoxigenic E. coli (ETEC): Profuse watery diarrhea (Traveler’s diarrhea) o Enteropathogenic E. coli (EPEC): infants; diarrhea w/mucus but no gross blood o Enteroinvasive E. coli (EIEC): blood, mucus, and many leukocytes in stool o Enterohemorrhagic E. coli (EHEC): Bloody diarrhea w/o pyuria. May progress to HUS. ♣ Shiga-toxin producing E. coli (STEC) via E. coli O157:H7 o Enteroaggressive E. coli (EAggEC): Watery diarrhea w/blood and mucus

21

MoA for tetracyclines/glycylcyclines? - Static or cidal?

Reversibly bind 30S ribosomal subunit to inhibit ptn synth. - Bacteriostatic.

22

Mech of resistance for tetracyclines/glycylcyclines? (Which drug is more resistant to these mechs?)

- Efflux pumps - Ribosomal protection proteins - Enzymatic inactivation (Tigecycline more resistant to these mechs)

23

Where's an important body areas that Tetracyclines/Glycylcyclines, distribute to? - What about Bactrim?

Prostate - Same for bactrim

24

What 2 tetracyclines/glycylcyclines are excreted, unchanged, in the urine?

Demeclocycline/tetracycline

25

Do tetra/glycylcyclines have to be modified w/renal disease?

No - Doxycycline, minocycline (metab) and tigecycline (biliary) - excreted mainly by non-renal routes

26

What is tigecycline often used to treat?

Polymicrobial infections

27

Which demo is tetra/tigecycline contraindicated in?

Pregnant (category D) - Affects their children (e.g. teet

28

What's the MoA of sulfonamides? - Static or cidal?

Inhibits dihydropterate reductase (folate/purine synthesis) - Bacteriostatic.

29

What's the MoA of trimethoprim? - Static or cidal, when combined w/sulfas?

Inhibits dihydrofolate reductase - Becomes cidal w/bacteriostatic sulfas

30

What is another name for Trimethoprim-Sulfamethoxazole (TMP-SMX)? - How is the spectrum of activity/resistance affected when the drugs are combined?

Bactrim - Broader spectrum, decreased resistance

31

What organism group does bactrim not have activity against?

Anaerobes

32

What organisms are targeted by chloramphenicol?

- Gram-pos - Gram-neg - Anaerobes (+ and -), etc. (3rd world use only)

33

What is chloramphenicol's MoA? (cidal or static)

Binds 50S ribosomal subunit (bacteriostatic)

34

(MoA). In acidic pH, methenamine is converted to ammonia and ____________.

Formaldehyde

35

What is the MoA for nitrofurantoin?

Not well understood

36

Besides tetracyclines, what other drug class are di-tri-valent cations contraindicated in?

Fluoroquinolones (cipro, levo, moxi, gemi)