Wk. 15: Antibiotics Flashcards by Ashley Campbell

SCIP Measures related to prevention of surgical site infection (7)

SCIP-Inf1: Prophylactic antibiotics received within ___ h prior to surgical incision

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SCIP Measures related to prevention of surgical site infection (7)

SCIP-Inf2: Prophylactic antibiotic _______ for surgical patients

selection

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SCIP Measures related to prevention of surgical site infection (7)

SCIP 3: Prophylactic antibiotics discontinued within ____ h after surgery time (___ h for cardiac patients)

24
48

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SCIP Measures related to prevention of surgical site infection (7)

SCIP-Inf 4: Cardiac surgery patients with controlled 6 am postoperative serum glucose (</= _____mg/dL)

200

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SCIP Measures related to prevention of surgical site infection (7)

SCIP-Inf 5: Postoperative _____ infection diagnosed during index hospitalization

wound

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SCIP Measures related to prevention of surgical site infection (7)

SCIP-Inf 6: Surgical patients with appropriate _______ removal

hair

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SCIP Measures related to prevention of surgical site infection (7)

SCIP-Inf 7: Colorectal surgical patients with immediate post-operative __________

normothermia

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The use of antimicrobial prophylaxis in surgery involves a _____ - ___ -_______ evaluation

risk-to-benefit

(risk of infection is high enough that it warrants use of ABX)

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Prophylactic antimicrobials should be administered intravenously within ___ hour of surgical incision

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Antibiotic treatment is not recommended for longer than ___ hours

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With a ____ therapeutic index and ____ incidence of side effects, cephalosporins are the antimicrobials of choice for most surgical procedures

wide
low

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Cephalosporins can be safely used in patients with an allergic reaction to penicillins that is not an ___-mediated reaction (anaphylaxis, urticaria, bronchospasm) or exfoliative dermatitis (_______-___________ syndrome)

IgE
Stevens-Johnson

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In patients with IgE-mediated reactions to cephalosporins, consider _________ antibiotics, ________, or ____________

beta lactam
clindamycin
vancomycin

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__________ is recommended for colonization or infection with methicillin-resistant Staphylococcus aureus (MRSA) or known IgE-mediated response to beta-lactam antibiotics

Vancomycin

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_____________ colitis is the most frequent complication of prophylactic antimicrobials, including the IV cephalosporins

Pseudomembranous

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__________ of the causative organism is essential for the selection of appropriate antimicrobial drugs to treat ongoing infection

Identification

(Not prophylactic; treating a specific infection)

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Nearly 80% of nosocomial infections occur in three sites:

Urinary tract
Respiratory system
Bloodstream

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The incidence of nosocomial infections is highly associated with the use of devices such as ________, ________, and __________

ventilators
vascular access catheters
urinary catheters

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_______ _______ _________ are the most common cause of bacteremia or fungemia in hospitalized patients

Intravascular access catheters

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The organism infecting access catheters most commonly comes from the colonized hub or lumen and reflect _____ ______
-S. _______
-Staphylococcus __________

skin flora
S. aureus
Staphylococcus epidermidis

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Initial therapy of suspected intravascular catheter infection usually includes _________ because of the high incidence of MRSA in the nosocomial environment

vancomycin

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Most antimicrobials cross the ________ and enter _________ _______

placenta
maternal milk

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The immature fetal liver may lack ________ necessary to metabolize certain drugs such that pharmacokinetics and toxicities in the fetus are often different from those in older children and adults

enzymes

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__________ is a concern when any drug is administered during early pregnancy

Teratogenicity

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In elderly patients, altered oral _____, _______, _______, and _______ of antimicrobials can be expected

absorption, distribution, metabolism, and excretion

Penicillins and cephalosporins don't need significant changes in dosages in elderly patients who have normal serum _________ concentrations

creatinine

Administration of __________ and __________ to elderly patients may require adjustments in dosing regimens

aminoglycosides vancomycin

There has been concern about increased risk of postoperative infection in HIV-infected patients based on their increased risk for _______ infection in the setting of reduced ___ cell counts Goal is preoperative control on an ____________ regimen with preserved T4 cell counts

opportunistic T4 antiretroviral

The bactericidal action of penicillins reflects the ability of these antimicrobials to interfere with the synthesis of _________, which is an essential component of cell walls of susceptible bacteria

peptidoglycan

Cell membranes of resistant gram-negative bacteria are in general resistant to penicillins because they prevent ________ to sites where synthesis of _______ is taking place

Access Peptidoglycan

Penicillin is the drug of choice for treatment of __________, ___________, and ____________ infections

Penicillin Pneumococcal Streptococcal Meningococcal

Penicillin is the drug of choice for treating all forms of ___________ and ________ infections causing gas gangrene

actinomycosis clostridial

Prophylactic administration of penicillin is highly effective against __________ infections, accounting for its value in patients with ________ ______

streptococcal rheumatic fever

-_______ excretion of penicillin is rapid -____% to ____% of an intramuscular dose is excreted in the first hour -Plasma concentration decreases to ___% of its peak value within 1 hour after injection

Renal 60% to 90% 50%

Methods to prolong the duration of action of penicillin include the simultaneous administration of ________, which blocks the ______ ______ secretion of penicillin

probenecid renal tubular

Procaine penicillin contains ____ mg of the local anesthetic for every _____ units of penicillin _______ to procaine must be considered

120 300,000 Hypersensitivity

The major mechanism of resistance to the penicillins is bacterial production of ___ -________ enzymes that hydrolyze the beta-lactam ring, rendering the antimicrobial molecule inactive

beta-lactamase

Penicillinase-Resistant Penicillins Methicillin, oxacillin, nafcillin, cloxacillin, and dicloxacillin are not susceptible to hydrolysis by ____________ _______________

staphylococcal penicillinases

Penicillinase-Resistant Penicillins Penetration of Nafcillin into the central nervous system is sufficient to treat staphylococcal _________

meningitis

Penicillinase-Susceptible Broad-Spectrum Penicillins (Second-Generation Penicillins) Broad-spectrium penicillins have a wider range of activity than other penicillins, being bactericidal against gram-_______ and gram-______ bacteria

postive negative

Penicillinase-Susceptible Broad-Spectrum Penicillins (Second-Generation Penicillins) They are all inactivated by ________ produced by certain gram-negative and gram-positive bacteria Therefore, these drugs are not effective against most _________ infections

penicillinase staphylococcal

Ampicillin has a broader range of activity than _________ ___

penicillin G

Ampicillin's spectrum encompasses not only pneumococci, meningococci, gonococci, and various streptococci but also a number of gram-negative bacilli, such as H. ________ and E. ________

influenzae coli

Approximately ____ % of an oral dose of ampicillin is excreted unchanged by the kidneys in the first __ hours, emphasizing that ______ function greatly influences the duration of action of this antimicrobial

50% 6 renal

Among the penicillins, ampicillin is associated with the highest incidence of ________, __%, which typically appears ___ to __ days after initiation of therapy Often due to _______ impurities in the commercial preparation of the drug and does not represent true allergic reactions

skin rash 9% 7 to 10 protein

Amoxicillin's spectrum of activity is identical to _________, but it is more efficiently absorbed from the __________ ______ than ampicillin, and effective concentrations are present in the circulation for ____ as long

ampicillin gastrointestinal tract twice

Extended-Spectrum Carboxypenicillins (Third-Generation Penicillins) Carbenicillin is effective when treating infections caused by Pseudomonas aeruginosa and certain Proteus strains that are resistant to __________

ampicillin

Extended-Spectrum Carboxypenicillins (Third-Generation Penicillins) Carbenicillin is not absorbed from the ____________ tract, therefore it must be administered __________

gastrointestinal parenterally

Extended-Spectrum Carboxypenicillins (Third-Generation Penicillins) Approximately ___% of unchanged carbenicillin is recovered in urine over ___ hours

85% 9

Extended-Spectrum Carboxypenicillins (Third-Generation Penicillins) Carbenicillin- Congestive heart failure may develop in susceptible patients in response to this acute drug-produced ______ load Watch for __________ and __________ _______

sodium hypokalemia metabolic alkalosis

Extended-Spectrum Carboxypenicillins (Third-Generation Penicillins) *Carbenicillin interferes with normal ______ _______ such that bleeding time is ________ but platelet count remains normal*

platelet aggregation prolonged

Extended-spectrum acylaminopenicillins (fourth-generation penicillins) Have the ______ spectrum of activity of all the penicillins

broadest

Extended-spectrum acylaminopenicillins (fourth-generation penicillins) Like the carboxypenicillins, the acylaminopenicillins are derivatives of ___________

ampicillin

Extended-spectrum acylaminopenicillins (fourth-generation penicillins) These drugs are ineffective against ________ -producing strains of _________

penicillinase S. aureus

Penicillin beta-lactamase inhibitor combinations Clavulanic acid, sulbactam, and tazobactam are beta-lactam compounds that bind _______ to the beta-lactamase enzymes that are produced by many bacteria, thus _________ these enzymes and rendering these organisms sensitive to beta-lactamase-susceptible penicillins

irreversibly inactivating

Cephalosporins, like penicillins, are _________ antimicrobials that inhibit _______ ____ ____ synthesis and have a low intrinsic ________

bactericidal bacterial cell wall toxicity

Like the newer penicillins, the new cephalosporins have _____ spectrum antimicrobial action

broad

Nephrotoxicity owing to cephalosporins, with the exception of ________, is less frequent than after administration of ______ or ________

cephaloridine aminoglycosides polymyxins

The incidence of allergic reactions in patients being treated with cephalosporins ranges form ___% to ___%

1% to 10%

The majority of allergic reactions to cephalosporins consist of ________ manifestations that occur ___ hours after drug exposure

cutaneous 24

Life-threatening anaphylaxis in cephalosporins is estimated to occur in ____%

0.02%

Cephalosporins share immunologic _______-_______, and are likely to be allergic to others

cross-reactivity

*The possibility of cross-reactivity between ________ and penicillins seems to be very __________, and are often used as alternatives in patients with a penicillin allergy*

cephalosporins infrequent (if you have a patient with a penicillin allergy, you don't have to do anything special when giving a cephalosporin)

The presence of a common nucleus (___ -______ ring) in the structure of all penicillins means that allergy to one penicillin increases the likelihood of an allergic reaction to another penicillin Actual cross-reactivity is _______

beta-lactam

Cephalosporins are classified because of their _________ spectrum -First generation -Second generation -Third generation

antimicrobial spectrum

First-generation cephalosporins are inexpensive, exhibit ____ toxicity, and are as active as second-and third-generation against __________ and _____________ streptoccci

low staphylococci nonenterococcal

_______- __________cephalosporins commonly used for prophylaxis in cardiovascular, orthopedic, biliary, pelvic, and intraabdominal surgery

First-generation

*All cephalosporins can penetrate into _______ and can readily cross the ________*

joints placenta

_________ is the prototype of first-generation cephalosporins

Cephalothin

Cephalothin (first-gen cephalosporin) Excreted largely unaltered by the _______, emphasizing the need to decrease the dose in the presence of _______ dysfunction

kidneys renal

Cephalothin (first-gen cephalosporin) Oral absorption is ______ and IM injection is _______, commonly administered IV Does not enter the ________ in significant amounts and is not recommended for treatment of meningitis

poor painful CSF

Cefazolin has essentially the same antimicrobial spectrum as _________ but has the advantage of achieving higher _______ ______, presumably due to slow _____ elimination

cephalothin blood levels renal

*___________ is viewed as the drug of choice for antimicrobial prophylaxis for many surgeries* This drug is well tolerated after ___ or ___ injection

Cefazolin IV or IM

_________ and _________ are examples of second-generation cephalosporins with extended activity agains gram-________ activity

Cefoxitin Cefamandole negative

Cefoxitin is resistant to _________ produced by gram-_______ bacteria

cephalosporinases negative

Cefamandole is pharmacologically similar to cefoxitin, but its methylthiotetrazole side chain poses a risk of __________ and disulfiram-like reactions with concurrent use of ________

bleeding alcohol

Both cefoxitin and cefamandole are excreted predominantly _______ by the __________

unchanged kidneys

*Third-generation cephalosporins have an enhanced ability to resist ________ by the _____-_________ of many gram-_______ bacilli*

hydrolysis beta-lactamases negative

Third-generation cephalosporins achieve therapeutic levels in the __________ ______, and can be used to treat meningitis

cerebrospinal fluid

Ceftriaxone has the longest _______ _____- ______ of any third-generation cephalosporin and is highly effective against gram-_______ bacilli

elimination half-time negative

Aminoglycoside antimicrobials are poorly ____ -_______ antimicrobials that are rapidly bactericidal for aerobic gram-________ bacteria

lipid-soluble negative

<____% of an orally administered aminoglycoside is absorbed

We see a linear relationship between the plasma ________ concentration and the ______ ____-_____ of aminoglycosides

creatinine elimination half-time

Aminoglycosides Streptomycin is rarely selected because of the rapid emergence of ________ organisms, the frequent occurrence of ________ damage during prolonged treatment, and the availability of less toxic antimicrobials

resistant vestibular

Aminoglycosides Gentamicin is active against P. aeruginosa as well as the gram-_______ bacilli Penetrates _______, ________, and ________ fluids in the presence of inflammation

negative pleural, ascitic, synovial

Aminoglycosides Monitoring plasma concentrations of gentamicin is the best approach for recognizing potentially toxic levels (>____mcg/mL)

Aminoglycosides Neomycin is commonly used for ______ application to treat infections of the ______, _______, and _______ membranes

topical skin cornea mucous membranes

Aminoglycosides Allergic reactions occur in ___% to ___% of patients treated with topical neomycin

6-8%

Aminoglycosides Oral neomycin does not undergo systemic absorption and is thus administered to decrease bacterial flora in the ________ before gastrointestinal surgery and as an adjunt to the therapy of _______ _______

intestine hepatic coma

Side effects of Aminoglycosides (3)

Ototoxicity Nephrotoxicity Skeletal muscle weakness

Aminoglycosides Ototoxicity reflects drug-induced destruction of _______ or _______ sensory hairs that is dose-dependent and most likely occurs with chronic therapy, especially in elderly patients, in whom ______ dysfunction is more likely

vestibular cochlear renal

Aminoglycosides *________, __________, and probably other diuretics seem to accentuate the ________ effects of aminoglycosides*

Furosemide, mannitol ototoxic

Nephrotoxicity: Aminoglycosides can produce acute ________ _______ that initially manifests as an inability to ________ urine and the appearance of ___________ and _____ ______ ______ casts Usually _________ is the drug is discontinued

tubular necrosis concentrate proteinuria red blood cell reversible

________ is the most nephrotoxic of the aminoglycosides and therefore is not administered by the ______ route

Neomycin parenteral

Aminoglycosides Skeletal muscles weakness is mostly likely because of the inability of aminoglycosides to inhibit prejunctional release of _______ while also decreasing postsynaptic sensitivity to the neurotransmitter IV administration of _______ overcomes the effect of aminoglycosides at the neuromuscular junction Administration of a single dose of an aminoglycoside is _______ to produce skeletal muscle weakness is an otherwise healthy patient

acetylcholine calcium unlikely

Macrolides are stable in the presence of ______ _______ fluid, and as a result, these antimicrobials are well absorbed from the ________ tract

acidic gastric gastrointestinal

Macrolides Erythromycin has a spectrum of activity that includes most gram-________ bacteria

positive

Macrolides In patients who cannot tolerate penicillins or cephalosporins, erythromycin or clindamycin are an effective alternative for treatment of streptococcal _________, _________, and ___________

pharyngitis bronchitis pneumonia

Macrolides Severe ______ and ______ may accompany infusion of erythromycin

nausea and vomiting

Macrolides Effects on QTc: *Oral erythromycin ________ cardiac _________ and is associated with reports of ______ ___ _______*

prolongs repolarization torsades de pointesMacrolides

Macrolides Azithromycin resembles _______ in its antimicrobial spectrum, but an extraordinarily prolonged ________ ____-________, ____ hours, permits once-a-day dosing for ___ days

erythromycin elimination half-time 68 5

Clindamycin resembles ___________ in antimicrobial activity, but it is more active against many ________

erythromycin anaerobes

Because severe ___________ colitis can be a complication of clindamycin therapy, this drug should be used only to treat infections that cannot be adequately treated by less toxic antimicrobials

pseudomembranous (a "backup" agent)

Clindamycin produces prejunctional and postjunctional effects at the ___________ ________ , and these effects cannot be readily antagonized with _______ or ___________ drugs

neuromuscular junction calcium anticholinesterase

Large doses of _________ can induce profound and long-lasting neuromuscular blockade in the absence of nondepolarizing muscle relaxants and after full recovery from succinylcholine has occurred

clindamycin

Vancomycin is a bactericidal __________ antimicrobial that impairs cell wall synthesis of gram-________ bacteria

glycopeptide positive

The oral route of administration for vancomycin is used only for the treatment of staphylococcal ___________ and antimicrobial-associated _______________ ___________ _______ absorbed from the gastrointestinal tract

enterocolitis pseudomembranous enterocolitis Poorly

*Vancomycin is administered IV for treatment of severe ___________ infections or _____________ or ____________ endocarditis in patients who are allergic to penicillins or cephalosporins*

staphylococcal streptococcal enterococcal

___________ is the drug of choice in the treatment of infections caused by methicillin-resistant S. aureus (MRSA)

Vancomycin

When vancomycin is administered iv, the recommendation is to infuse the calculated dose (_____ to _____mg/kg) over ____ mins to minimize the occurrence of drug-induced _______ release and _________ Begin ___ hours prior to surgery for prophylaxis

10-15 60 histamine hypotension 2

Vancomycin is principally excreted by the _____, with ___% of a dose being recovered unchanged in the urine

kidneys 90%

Rapid infusion of vancomycin (< 30 minutes) has been associated with profound _________ and even ________ ______

hypotension cardiac arrest

Hypotension during vancomycin infusion is often accompanied by signs of _________ release characterized by intense facial and truncal erythema "red man syndrome"

histamine

Vancomycin may produce allergic reactions characterized as __________ with associated ________, _______, and occasionally _______________

anaphylactoid hypotension erythema bronchospasm

Oral H1 (__________ 1 mg/kg) and H2 (____________ 4mg/kg) receptor antagonists administered 1 hour before induction of anesthesia decrease histamine-related side effects of rapid vancomycin infusion (1g over 10 mins)

diphenhydramine cimetidine

_________ is likely when persistent high plasma concentrations of vancomycin (> 30 mcg/mL) are present

Ototoxicity

Bacitracins are a group of ________ antibiotics effective against a variety of gram-________ bacteria

polypeptide positive

Use of bacitracins are limited to ________ application in _________ and ________ ointments

topical ophthalmologic dermatologic

Metronidazole is bactericidal against most ________ gram-_________ bacilli and _______ species

anaerobic negative Clostridium

Metronidazole has been useful in treating -CNS, ____, and ____ infections -______ and pelvic sepsis -_________

bone, joint abdominal endocarditis

Metronidazole is a useful part of preoperative prophylactic regimens for elective ________ surgery

colorectal

Side effects of metronidazole include (3)

Dry mouth Metallic taste Nausea

Concurrent ingestion of alcohol with metronidazole may cause a reaction similar to that produced when alcohol is ingested by patients taking ________

disulfiram

Fluoroquinolones are _____-spectrum antimicrobials that are bactericidal against most enteric gram-_______- bacilli

broad negative

The dose of fluoroquinolones should be decreased in the presence of ______ dysfunction

renal

Fluoroquinolones have been useful clinically in the treatment of __________ and _________ infections

genitourinary gastrointestinal

*Fluoroquinolones are associated with an increased risk of _________ and _________ _______*

tendinitis tendon rupture

Fluoroquinolones Ciprofloxacin is highly effective in the treatment of ______ and ______ _____ infections, including __________ and ___________ infections

urinary genital tract prostatitis gastrointestinal

Fluoroquinolones Moxifloxacin is long acting for the treatment of acute _______ ________, acute bacterial exacerbation of chronic __________, community-acquired _________, skin infections, and complicated intraabdominal infections

bacterial sinusitis bronchitis pneumonia

Fluoroquinolones Because of serious _______ effects of moxifloxacin, use is recommended only when less toxic options are not available MANY adverse effects

adverse

Cefazolin redose

4 h

Clindamycin redose

6 h

Vancomycin redose