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Flashcards in Antibiotics - bacterial Deck (75):
1

4 types of antimicrobials?

bacterial
fungal
viral
other: mycobacterium, parasites

2

two ways to classify antibiotics by scope?

narrow spectrum: relatively small # of specific organisms will be sensitive to that agent (ex. penicillin)
broad spectrum: broad range of organisms will be sensitive to that agent (ex. piperacillin/tazobactam)

3

5 MOAs for antibiotics?

1. inhibition of cell wall synthesis (penicillin, bacitracin, cephalosporin, vancomycin)
2. disruption of cell membrane function (polymyxin)
3. inhibition of protein synthesis (tetracycline, erythromycin, streptomycin, chloramphenicol)
4. inhibition of nuclei acid synthesis (rifamycin, quinolones, metronidazole)
5. action as antimetabolites (sulfonilamide, trimethoprim)

4

two ways to categorize abx by their killing capabilities?

bacteriostatic: keep at the # that is there
bactericidal: kill the bacteria off

5

two ways to categorize antimicrobials by pharmacodynamic profiles?

time dependent
concentration dependent

6

different categories of bugs?

gram (+): streptococci, staphylococci, enterococci
gram (=): enterobacteriaceae, pseudomonas
anaerobes: bacteroides fragilis

7

general bacterial classifications?

aerobe vs anaerobe
gram (+) vs gram (=)

8

shapes of bac?

cocci or rods

9

important aerobic gram (+) cocci?

staphylococci: s. aureus, coag-negative staph
streptococci: s. pneumoniae, group B strep, viridans strep
enterococci: e. faecalis, e. faecium

10

important aerobic gram (=)?

gram (=) rods: e. coli, k. pneumoniae, serratia, enterobacter, h. influenze, p. aeruginose
gram (=) cocci: m. catarrhalis, m. gonorrhoeae, n. meningitidis

11

important atypical respiratory aerobes? what makes them atypical?

legionella spp, mycoplasma pneumonia, chlamydia pneumoniae
lack a cell wall, intracellular organisms & can't be seen w/gram staining process

12

where do true anaerobes generally live?

the gut!
bacteroides fragilis
clostridium difficile (causes diarrhea)

13

two oral anaerobes?

prevotella
peptostreptococcus

14

what is sensitivity in relation to abx?

the degree to which microbial organisms are killed or their proliferation is arrested by the drug

15

4 factors that determine sensitivity of microbes?

1. reach microorganism
2. bind to or enter the microorganism
3. interfere w/vital microbial fxn
4. remain chemically intact while acting upon the microorganism

16

how to test a bugs sensitivity to a drug?

done in vitro
dilution tests: minimum inhibitory concentration; minimum bactericidal concentration
disk-diffusion technique

17

7 ways to categorize abx via chemical structure?

1. sulfonamides
2. penicillins
3. cephalosporins
4. macrolides
5. tetracyclines
6. quinolones
7. others

18

what is the main structure that inhibits cell wall synthesis?

beta-lactam ring structure

19

MOA of penicillin? two ways for bugs to have resistance?

MOA: B-lactam inhibits cell wall synthesis by binding to penicillin binding proteins
resistance via B-lactamases & altered PBPs

20

is penicillin time or dose dependent? bacteriostatic or bacteriocidal?

time dependent
bacteriocidal

21

4 different types of penicillins and penicillin congeners?

natural penicillin (penicillin G and penicillin VK)
aminopenicillins (amoxicillin, ampicillin)
penicillinase-resistance penicillins (methicillin, where we hear about MRSA)
extended spectrum PCNs + beta-lactamase inhibitor (piperacillin, tazobactram)

22

effective uses of penicillin? bioavailability? spectrum of use? given how?

often resistant b/c bacterial have evolved so only a few we can treat w/penicillin: gram (+) streptococci, oral anaerobes
drug of choice for N. meningitidis, syphilis
poor bioavailability, narrow spectrum of use
give per IV

23

penicillinase-resistant penicillin use?

naficillin
major drug used for MSSA
can be used to tx gram (+) strep and MSSA and oral anaerobes

24

two examples of aminopenicillins? aminopenicillins MOA? used to tx what?

ampicillin, amoxicillin
MOA: binds to PBPs and inhibits synthesis of cell wall
used to tx respiratory infxn (not as common anymore),, sinusitis, otitis, lower respiratory tract infxns, endocarditis from enterococcus
can be used to tx gram (+) strep and enterococci; some gram (=)s, oral anaerobes

25

ex of extended-spectrum penicillins?
spectrum? bugs it can treat? how to use?

piperacillin
broad spectrum, severe infections
gram (+) strep, staph, possibly eneterococci
gram (=)- excellent- pseudomonas aeruginosa
given in combo w/B-lactamase inhibitor so it can act on those bugs which produce the B-lactamase

26

MOA of B-lactamase inhibitors?

increase treatment capacity against MSSA and enterobactieraceae and anaerobes

27

bugs pencillin/B-lactamase inhibitor can be used on?

gram (+) strep, MSSA, maybe enterococci
gram (=) P. aeurginosa
all anaerobes

28

possible adverse rxns with penicillins?

allergic reaction: anaphylaxis, rash, urticaria, fever
5-20% report allergy, <20% who think they have an allergy actually have an allergy
diarrhea

29

type I allergic reaction? common to see in what type of abx?

IgE
occur w/in 1 hr of dose
urticarial rash, pruritis, flushing, angioedema of face or laryngeal tissues, wheezing, hypotension
anaphylaxis
common to see w/B-lactam drugs; ~5% cross reactivity w/cephalosporins if true allergy

30

4 less common adverse penicillin rxns?

hematologic: anemia, thrombocytopenia
hepatitis w/nafcillin/oxacillin
interstitial nephritis: nafcillin/oxacillin
seizures: high doses, renal failure

31

SEs of amoxicillin and clavulanate/augmentin?

notable increased SEs from clavulanic acid, clavulanate alone has very little antimicrobial activity but causes copious GI distress and diarrhea

32

what is the most severe cause of abx induced diarrhea?

pseudomembranous colitis (c. difficile colitis)

33

most of the abx are cleared in which way?

most are cleared renally

34

what is the only major interaction w/amoxicillin?

acacia

35

MOA of cephalosporins?

binds to beta-lactam ring of cell wall and inhibits organisms ability to form new cell walls

36

between 1st, 2nd, 3rd and 4th generation cephalosporins, which have the greatest activity against gram (+)s, against gram (=)s?

1st and 2nd have greatest activity against gram (+)s
3rd and 4th have greatest activity against gram (=)s

37

what bug do cephalosporins NEVER cover??

enterococcus

38

1st generation cephalosporins use? what bugs does it cover?

indications: UTIS, skin infxns, some respiratory and prophylaxis surgically
used against gram (+) strep, MSSA; gram (=) e. coli, klebsiella; oral anaerobes
can be used as an alternative to penicillin allergic pts

39

2nd generation cephalosporins use? what bugs does it cover?

indicated in some respiration and GI infections
gram (+) strep, MSSA
gram (=)- good coverage overall
oral anaerobes + b. fragilis

40

3rd generation cephalosporin use? bugs it covers?

use: respiratory infxns, serious infxns
gram (+) strep, MSSA
gram (=): very good, p. aeruginosa
oral anaerobes
some are able to cross BBB

41

4th generation cephalosporin use? what bugs?

serious hospital infxns
gram (+) strep and MSSA
gram (=): excellent, p. aeruginosa
oral anaerobes only

42

what can 5th generation cephalosporins cover?

MRSA
strep pneumonia
covers GNR, but not pseudomonas

43

exceptions of cephalosporins that are not cleared renally?

ceftriaxone so don't need to adjust for reduced renal fxn

44

ADRs of cephalosporins?

allergic rxns: anaphylaxis, rash, urticaria, fever, 3-7% cross resistance with penicillin allergy
diarrhea
less common: anemia, thrombocytopenia, seizures when given at high doses

45

two other beta-lactam drugs? MOA? what can provide bugs w/resistance?

monobactams and carbapenems
MOA: inhibit cell wall synthesis
resistance via B-lactamases, outer membrane protein mutations
very broad spectrum, sever infxns in hospital

46

macrolides use? bugs it covers?

erythromycin, azithromycin
good coverage of respiratory infections, chlamydia, syphilis, gonorrhea, sinusitis, bronchitis, COPD
gram (+) strep, MSSA, pneumococci
gram (=) minimal w/h. flu
oral anaerobes
useful in treating atypical respiratory pathogens such as legionella, chlamydia, mycoplasma

47

ADRs of macrolides?

GI: n/v, diarrhea b/c cause direct (+) motility of gut; erythro is worse than clarithro which is worse than azithro
phlebitis with IV erythro
less common: prolonged QT interval
hepatotoxicity

48

what enzyme do macrolides inhibit?

CYP450-3A4

49

4 major interactions with azithromycin?

all possibly prolong the QT segment
cesium, ephedra, oleander, sida cordifolia

50

MOA of tetracyclines?

inhibit protein synthesis by binding to the 30s ribosomal subunit (inhibits translation)
bacteriostatic

51

what can tetracyclines be used to tx?

increased resistance limits their use
respiratory, intracellular infxns, acne and rosacea, chlamydia, SSTI
gram (+) strep, MSSA
gram (=) h. flu, rickettsiae, other gram (=)s often resistance
oral anaerobes
atypical respiratory pathogens such as legionella, clamydia pneumonia, mycoplasma pneumonia

52

ADRs of tetracyclines?

photosensitivity
nausea
diarrhea
tooth discoloration in children (C/I in children less than 8 and PG)
less common: esophagitis, leukocytosis

53

what can tetracyclines not be given with? can be used in what populations?

do not give with Ca2+ supplements as it causes chelation of calcium ions
can be used in those who are PNC allergic
can be used in renal failure

54

MOA of sulfonamids?

inhibits folic acid synthesis via enzyme inhibition
bacteriostatic

55

can combine sulfamethoxazoe w/what other abx? what will this combo cover? what can this combo be used to tx?

can be combined with trimethoprim/bactrim
variable wide activity when used in combo
gram (+) strep, MSSA, CAMRSA
gram (+) most enterobacteriaceae
oral anaerobes
indications: UTI, otitis media, sinusitis, bronchitis, pneumocystitis prophylaxis, community acquired MRSA, SSTI
there is however increasing resistance

56

ADRs of bactrim? what drug does it specifically act with to increase its effects?

allergic rxns, rash, fever, photosensitivity, urticaria, GI effects, neutropenia, thrombocytopenia (folate deficiency)
rare: Steven Johnsons Syndrome (severe rash)
increases effects of warfarin!

57

MOA of fluroroquinolones? resistance mechanisms?

MOA: inhibits bacterial DNA gyrase, inhibiting DNA replication and transcription, bactericidal
resistance: mutations at target sites, efflux pumps

58

bugs fluoroquinolones can act against?

potent broad-spectrum agent, most gram (=): p. aerugonisa
atypical pathogens: community acquired pneumonia- legionella, clamydia pneu, mycoplasma pneu

59

indications for fluoroquinolones? problems?

UTI, pyleo, upper and lower respiratory tract infxns, SSTI, joint infxns
increasing resistance
increase evidence of adverse rxns

60

ADRs of fluoroquinolones?

GI: nausea
CNS: h/a, dizziness, insomnia
less common: cartilage toxicity, AVOID use in children and PG, CNS: confusion, seizures; prolonged cardiac QT interval

61

interactions w/fluoroquinolones? need to be taken away from what items?

any drug that can prolong the QT interval
like the macrolides
cesium, ephedra, grapefruit, sidea cordifolia, sweet orange
need to take away from calcium, iron, antacids, enteral feeding

62

MOA of anti-anaerobes (metronidazole and clindamycin)? resistance how?

metronidazole: inhibits nucleic acid synthesis
clindamycin: ribosomal protein synthesis inhibitor
resistance: rare w/metron, mutations in ribosomes w/clinda

63

use metronidazole against what?

only anaerobes!
indications: vaginitis, h.pylori in PUD, c. difficle, associated diarrhea, intra-abdominal abscess, lung abscess, peritonitis

64

use clindamycin against what?

gram (+) and anaerobes
NO GRAM (=)s
indications: SSTI, anaerobic infxns, topical available for acne vulgaris, bacterial vaginosis

65

ADRs of metronidazole?

nausea, diarrhea, metallic taste
drug interaction: disulfiram rxn: flushing, sweating, nausea w/EtOH, can persist a few days after

66

ADRs of clindamycin?

diarrhea, nausea, c. difficile

67

indication of nitrofurantoin/macrobid? MOA?

indication: lower UTIs but NOT for pyelonephritis, considered safe before 38 wks gestation
MOA: disrupts both DNA and RNA of bacteria which are sensitive to the drug

68

SEs of nitrofurantoin/macrobid?

n/v, diarrhea
less common: fever, chills, pulmonary fibrosis
not recommended for pyelonephritis and not effective in significant renal impairment

69

additional abx classes for hospital severe infxns? MOA? what bugs can they be used against?

aminoglycosides
MOA: bactercidial, inhibit protein synthesis
can be used against gram (=0 such as pseudomonas auerginosa

70

6 abx that can be used effectively to treat MRSA?

IV vancomycin
daptomycin
telavancin
ceftaroline
tigecycline
linezolid

71

3 abx to use for community acquired MRSA (CAMRSA)

clindamycin
tetracycline
bactrim

72

6 drugs that cover pseudomonas?

aminoglycosides
ciprofloxacin, levofloxacin
ceftazidime, defepime, ceftolozane/tazobactam
piperacillin, ticarcillin
aztreonam
imimpenem, meropenem, doripenem

73

what abx provide true anaerobic coverage?

metronidazole
B-lactam/B-lactamase inhibitors
carbapenems
moxifloxacin
clindamycin
cefoxitin/cefotetan

74

topical abx?

mupirocin/bactroban
bacitracin
polysporin OTC (combo of bacitracin and polymyxin)
neosporin OTC (combo of bacitracin along with neomycin and polymyxin B

75

probiotic strains which have been proven to prevent c. difficile?

lactobacillus combos or single agent regiments