Chapter 17: Bacterial Infections Flashcards Preview

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Flashcards in Chapter 17: Bacterial Infections Deck (121):
1

 

 

Natural bacterial barriers include

 

skin

mucous membranes

lactic acid

long-chain fatty acids

lysozymes

reticuloendothelial system

2

 

 

bacterial barriers other than the body's natural ones

 

overall health

age

nutritional status

comorbidities

blood supply near infection site

natural and acquired antibodies

3

 

 

most commonly used classes of antibiotics

 

PCNs

fluoroquinolones

cephalosporins

macrolides

tetracyclines

4

 

 

bacteriocidal antibiotics

 

 

kill the invading organism

5

 

 

bacteriostatic antibiotics

 

 

inhibit growth of invading organism so the body's defenses can kill it

6

 

 

methods by which antimicrobial drugs effect the invading microbe

 

  1. inhibition of cell wall synthesis/repair
  2. inhibition of protein synthesis
  3. disruption of membrane permeability
  4. inhibition of nucleic acid synthesis
  5. inhibition of specific biochemical pathways

7

 

 

cell wall structure of gram- and gram+ bacteria

 

 

gram + tends to be a simpler structure and easier to damage

8

 

 

empricial prescribing

 

 

prescribing based on previous experience when treatment must be started prior to lab results

 

9

 

 

what are the 3 things used to classify all organisms

 

morphology (cocci, bacilli)

growth characteristics (anaerobic, aerobic)

other qualities (gram+, gram-)

10

 

 

patient education for antimicrobials

 

take as prescribed and finish entire course

do not take for viral infections

do not take someone else's

patient's should ask about potential for resistance

11

 

 

which 2 agents are most commonly asociated with clinically significant drug interactions

 

 

quinolones and macrolides

12

 

 

interactions between ABTs and other medications

 

 

coumadin interacts with many

birth control with PCN

13

 

 

classess of bacteriocidal ABTs that affect cell wall synthesis

 

 

 

 

Natural Penicillins

expanded-spectrum PCNs

extended spectrum PCNs

penicillinase resistant PCNs

14

 

 

4 groups of PCNs

 

natural PCNs

PCN G

PCN V

aminopenicillins (amoxicillin, ampicillin)

15

 

 

signs of superinfection to watch for when prescribing PCNs

 

abdomina cramps

fever

watery diarrhea

 

 

16

 

 

hypersensitivity reactions to PCN can include

 

 

 

 

angioedema

serum-sickness

anaphylaxis

severe local inflammaotory reaction at injection site

17

 

 

PCNs effect on Comb's test

 

 

 

 

can cause false positive

18

 

 

IV administration of PCN G, K+, or Na_

 

 

administer slowly

19

 

 

other conscientious consideration with prescribing PCNs

 

 

renal impairment may require dosage adjustments

20

 

 

PCN patient education

 

  • oral tabs 1hr before or 2hr after meals
  • take all medication for 14 days
  • alternate birth control
  • doses should be dividied equally over 24 hour period
  • notify clinicain if blood, pus, mucus in stool

21

 

 

important pieces to remeber about pharmacokinetics of PCNs

 

GI absorption is variable

widely distributed (crosses CSF and breast milk)

partial metabolism in liver but mostly excreted unchanged in urine

more page 316

22

 

 

which medications can inhibits PCN bacteriocidal activity

 

 

 

chloramphenicol

macrolide ABTs

methotrexate

tetracycline

23

 

 

what effect does probenecid have on PCNs and cephalosporins

 

 

potentates activity by raising their blood levels

24

 

 

contraindications for natural PCNs

 

 

infectious mononucleosis as it can cause extensive rash

25

 

 

cross sensitivity of PCN and cephalosporin sensitivity

 

 

about 10%

26

 

 

extended-spectrum PCNs

(cephalosporins)

 

 

semisynthetic agents

27

 

 

how are cephalosporins grouped

 

4 generations based on antimicrobial properties

 

28

 

 

things to remember in general about cephalosporins

 

low toxicity

broad spectrum of activity

not reliable against MRSA

29

 

 

action of cephalosporins 

 

1st generation is more useful among gram+

as classification increases, so does spectrum, and ability to effect gram-

30

 

 

cephalosporin mechanism of action

 

 

interferes with bacterial cell wall synthesis

(Bacteriocidal)

31

 

 

some clinical uses of cephalosporins

 

respirtaory tract infections

pneumonia

otitis media

skin infections not caused by MRSA or MRSE

more page 319

32

 

 

cephalosporin patient education

 

evenly space dosages around the clock

take missed dose ASAP but do not double

do not share

report signs of superinfection

do NOT self-treat any diarrhea that develops

33

 

 

hematologic side effects of cephalosporins

 

 

anemia, leukopenia

34

 

 

cephalosporin interactions

 

 

 

 

aminoglycosides and LOOP diuretics can add to nephrotoxicity

anticoagulants can cause hypoprothrombinemia

35

 

 

cephalosporin contraindication

 

 

hypersensitivity

36

 

 

beta-lactamase resistant PCNs mechanism of action

 

 

resist the action of penicillinase and bind to the cell wall which causes cell death

37

 

 

what causes resistance to PCNs

 

 

invading microbe produces penicillinase which hydrolyzes the beta-lactam ring of the ABTs, rendering it ineffective

38

 

 

examples of penicillinase resistant PCNs

 

cabenicillin

geocillin

cloxacillin

dicloxacillin

methicillin

39

 

 

examples of first generation cephalosporins

 

cefadroxil (Duricef)

cephalexin (Keflex)

cefazolin (Ancef)

cephradine (Velosef)

40

 

 

examples of second generation cephalosporins

 

cefuroxime axetil (Ceftin)

cefprozil (Cefzil)

loracarbef (Lorabid)

cefotetan (Zinacef)

cefaclor (Cecor)

41

 

 

examples of third generation cephalosporins

 

ceftibuten (Cedax)

ceftriaxone (Rocephin)

cefotaxime (Claforan

cefixime (Suprax)

42

 

 

examples of fourth generation cephalosporins

 

 

cefdinir (Omnicef)

cefepime (Maxipime)

43

 

 

clinical uses of penicillinase resistant PCNs

soft tissue and bone infections

respiratory tract infections

sinusitis

UTIs

endocarditis

septicemia

meningitis

44

 

 

what decreases absorption of penicillinase resistant PCNs

 

 

gastric acids and acidic juices

45

 

 

extended spectrum PCNs mechanism of action

 

 

pass throught the pores in the outer membrane and can reach penicillin-binding proeins on inner cell's cytoplasmic membranes

46

 

 

examples of extended spectrum PCNs

 

amoxicillin

ampicillin

amoxicillin/clavulanate (Augmentin)

ampicillin/sulbactam (Unasyn)

47

 

 

why is amoxicillin preferred over ampicillin

 

 

it is more completely absorbed and has a lower incidence of diarrhea

48

 

 

How do macrolides work

 

 

they inhibit protein synthesis at the 50S ribosome unit

49

 

 

Antibiotics that inhibit protein synthesis

 

 

macrolides

tetracyclines

aminoglycoside

50

 

 

examples of macrolides

 

 

azithromycin (Z-pak)

erythromycin (E-mycin)

clarithromycin (Biaxin)

clindamycin

lincomycin (Linocin)

51

 

 

macrolide clinical uses

 

 

mild-mod bacterial exacerbations of COPD

mild-mod pharyngitis/tonsilitis caused by strep

PID

community-acquired pneumonia caused by strep or flu

52

 

 

conscientious considerations for macrolides

 

 

 

C&S is important

watch for nonadherance, anaphylaxis, drowsiness, superinfection

can take without regard to food

may cause photosensitivity

 

53

 

 

Azithromycin is a derivative of what

 

 

 

 

erythromycin

54

 

 

why is azithromycin one of the most popular ABT for respiratory, skin, and sexually transmitted infections

 

 

effective against so many gram+ and some gram- bacteria

55

 

 

how is azithromycin different from older macrolides

 

 

longer half-life 

56

 

 

what decreases peak serum levels of azithromycin

 

 

 

 

aluminum and magnesium containing antacids

57

 

 

what increases peak serum levels of azithromycin

 

 

digoxin, theophylline, and phenytoin triazolam

58

 

 

azithromycin contraindications

 

 

pregnancy/breastfeeding

liver impairment

sensitivity

59

 

 

absorption of erythromycin (Biaxin)

 

 

high but erratic

60

 

 

clinical uses for erythromycin (Biaxin)

 

 

legionnaire's disease

syphylis

diptheria

atypical pneumonia

topically for acne

61

 

 

what is often used as an alternative when a patient is allergic to PCN

 

 

Biaxin

62

 

 

erythromycin interactions

 

 

ALOT

ethanol reduces plasma concentrations

decreases activity of PCN if co-administered

63

 

 

erithromycin contraindications

 

 

hepatic disease or macrolide sensitivity

64

 

 

why is erythromycin preferred over tetracyclines in young people being treated for acne

 

 

does not discolor teeth or bind to bone

65

 

 

clinical uses of clindamycin

 

 

serious infections

most infections with gram- staph and strep

66

 

 

clindamycin mechanism of action

 

 

bacteriostatic or bacteriocidal

inhibits protein synthesis at the ribosome 50S unit

67

 

 

clindamycin interactions

 

 

kaolin/pectin preparations decrease absorption 

68

 

 

clindamycin contraindications

 

 

previous pseudomembranous colitis

severe liver impairment

diarrhea

alcohol tolerance

pregnancy/lactation

69

 

 

why are tetracyclines contraindicated in children and pregnancy

 

 

binds to calcium where it stains teeth and affects long bone development

70

 

 

examples of tetracyclines

 

doxycycline

tetracycline

minocycline

oxytetracycline

71

 

 

tetracycline mechanism of action

 

 

broad spectrum bacteriostatic agents that inhibit protein synthesis by binding to the 30S ribosome unit

72

 

 

clinical uses of tetracyclines

 

 

 

syphilis in PCN allergic patients

lyme disease. anthrax

adjunct to therapy for H. pylori ulcers

mycoplasma pneumoniae

(more page 325)

73

 

 

tetracycline interactions

 

 

increase effect of warfarin

decrease effect of sucralfate and barbituates

74

 

 

aminoglycoside mechanism of action

 

 

 

 

bind to ribosomal 30S and 50S subunits to inhibit protein synthesis which causes a defective cell membrane that cannot sustain the bacteria

75

 

 

makeup of aminoglycosides

 

 

contain at least one sugar

76

 

 

aminoglycosides clinical uses

 

serious bacteremia

respiratory/urinary tact infections

infected wounds

infected bone/soft tissues

perotinitis

burns complicated by sepsis

77

 

 

treatment of serious infections with pseudomonas aeruginosa

 

 

may require combined therapy with aminoglycosides and ticarcillin, carbenicillin, pipercillin, or ceftazidime

78

 

 

side effects to watch for with aminoglycosides

 

 

vestibular and cochlear disturbances, nephrotoxicity, hypersensitivities

79

 

 

aminoglycoside interactions

 

 

 

long list

most result in nephrotoxicity or ototoxicity

80

 

 

clinical considerations with aminoglycosides

 

 

poor oral absorption (most are IV)

therapy exceeding 7 days can cause kidney damage

resistance varies widely

81

 

 

sulfonamides mechanism of action

 

 

inhibits bacterial folic acid synthesis producing a bacteriostatic effect

82

 

 

examples of sulfonamides

 

 

sulfamethoxazole (Gantanol)

sulfamethoxazole/trimethoprim (Bactrim)

 

83

 

 

clinical uses of sulfonamides

 

 

infection with toxoplasma, pneumocystitis jiroveci pneumonia, shigella enteritis, and UTIs

84

 

 

sulfonamides as prophylaxis

 

 

against pneumocystitis in HIV and immucompromised patients

85

 

 

sulfonamide interactions

 

 

 

 

 

 

increases the hypoprothrominemia effect of arfarin by inhibiting its metabolism

86

 

 

sulfonamide patient education

 

 

 

notify if rash, sore throat, mouth sores, unusual bleeding

avoid driving until response is known

stay hydrated to prevent crystalluria

87

 

 

sulfonamide conscientious considerations

 

 

watch for stevens-johnson syndrome

G6PD deficiency can lead to anemia

hypersensitivities can occur up to 12 days after exposure

88

 

 

fluroquinolones mechanism of action

 

inhibits bacterial DNA synthesis to prevent replication

89

 

 

fluroquinolones are effective against

 

 

most aerobi gram- bacteria and some gram+

90

 

 

examples of fluroquinolones

 

ciprofloxacin (Cipro)

gatifloxacin (Tequin)

gemifloxacin (Factive)

levofloxacin (Levoquin)

moxifloxacin (Avelox)

ofloxacin (Floxin, Ocuflox)

91

 

 

respiratory quinolones

 

 

 

gemifloxacin, levofloxacin, and moxifloxacin

all have good activity against PCN-resistant strains of pneumonia

 

 

92

 

 

cipro is used widely for

 

 

 

 

enteric infections (bacterial enteritis and diverticulitis)

UTIs (including prostatitis)

bone/joint infections

 

 

93

 

 

what drugs have approval to treat uncomplicated gonorhhea

 

 

 

 

oxyfloxacin, norfloxacin, gatifloxacin, and ciprofloxacin

minimum of 7 day treatment

94

 

 

what are special use ABTs used for

 

 

parasitic and bacterial infections

95

 

 

examples of special use ABTs

 

metronidazole (Flagyl)

daptomycin (Cubicin)

tigecycline (Tygacil)

Linezolid (Zyvox)

Quinupristin/dalfopristin (Synercid)

96

 

 

metronidazole (Flagyl)

mechanism of action

 

 

causes metabolites to accumulate in the susceptible organism which disrupts DNA and protein synthesis

97

 

 

clinical uses of flagyl

 

anaerobic bacteria and some protozoa

intestinal parasite Giardia

vaginitis

amebic dysentery

trichomoniasis

tx of c-diff

more page 332

98

 

 

flagyl interactions

 

cimetidine can reduce metabolism

phenobarbital can increase metabolism

alcohol causes disulfiram-like reaction

99

 

 

symptoms of disulfiram-like reaction

 

headache, dizziness, flushing, nausea, sweating, hyperventilation, disorientation

100

 

 

flagyl contraindications

 

 

hypersensitivities

first trimester of pregnancy

101

 

 

flagyl conscientious considerations

 

use with caution in CNS diseases (potential for neurotoxicity)

 

102

 

 

flagyl patient education

severe interaction with alcohol

possible furry tongue and metallic taste

may darken urine

may take with food if GI upset occurs

103

 

 

daptomycin (Cubicin)

mechanism of action

 

 

cyclic lipopeptide with rapid bacteriocidal activity against wide variety of gram+ and bacteria resistant to vancomycin and methicillin

(binds to bacterial cell membrane)

104

 

 

clinical uses of daptomycin

 

 

 

complicated skin and skin structure infections

s. aureua bacteremia

right sided endocarditis

105

 

 

daptomycin interactions

 

 

none clinically significant

manufacturer warns against statin drugs d/t risk of myopathy

106

 

 

what can be done to minimize the risk of daptomycin resistance

 

 

always drain any abcesses

107

 

 

tigecycline (Tygacil)

mechanism of action

 

 

inhibits bacterial protein synthesis by binding to 30S ribosomes

chemically similar to tetracyclines

108

 

 

administration of Tygacil

 

 

IV only

109

 

 

clinical uses of Tygacil

 

severe skin and soft tissue infections

complicated intra0abdominal infections with resistant pathogens       (VRE, MRSA)

110

 

 

Tygacil interactions

 

 

oral contraceptives

111

 

 

tygacil contraindications

 

<18

pregnant/breastfeeding

112

 

 

linezolid (Zyvox)

mechanism of action

 

 

inhibits protein synthesis by binding to 50S ribosomal unit

treats nearly all gram+ resistant bacteria

113

 

 

major drawback of Zyvox

 

 

reversible thrombocytopenia

114

 

 

clinical uses of Zyvox

 

 

bacteriocidial: gram+ (sterptococci)

bacteriostatic: resistant enterococci and staphylococci

115

 

 

Zyvox interactions

 

 

dopaminergic, vasopressors, sympathomimetics should be reduced

(mild MAOI)

OTC cold medicines can increase BP

116

 

 

contraindications for Zyvox

 

not determined for pregnancy

caution with antiplatelets

117

 

 

quinupristin/dalfopristin

(Synercid)

mechanism of action

 

bacteriostatic

quinupristin inhibits late phase of protein synthesis

dalfopristin inhibits early phase of protein synthesis

118

 

 

Synercid clinical uses

 

 

treatment of infections with antibiotic resistant gram+ organisms

(VRE, MRSA, VREF)

119

 

 

Synercid interactions usually result in

 

 

increased risk of toxicity

listed page 335

120

 

 

pregnancy,geriatric, pediatric

 

 

page 336

121