Page 80 - Review of Medical Microbiology and Immunology ( PDFDrive )

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mebooksfree.com mebooksfree.com mebooksfree.com mebooksfree.com C H A P T E R mebooksfree.com
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10

Antimicrobial Drugs:

Mechanism of Action

mebooksfree.com mebooksfree.com mebooksfree.com CHEMOPROPHYLAXIS mebooksfree.com mebooksfree.com
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CHAPTER C ONTENT S

Alteration of Cell Membrane Function
ANTIMICROBIAL DRUG STEWARDSHIP
PRINCIPLES OF ANTIMICROBIAL THERAPY
Additional Drug Mechanisms
BACTERICIDAL & BACTERIOSTATIC ACTIVITY
PROBIOTICS
MECHANISMS OF ACTION
Inhibition of Cell Wall Synthesis
Pearls
Inhibition of Protein Synthesis
Self-Assessment Questions
Practice Questions: USMLE & Course Examinations
Inhibition of Nucleic Acid Synthesis
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mebooksfree.com mebooksfree.com mebooksfree.com antibiotic use can occur for many reasons, including the mebooksfree.com
ANTIMICROBIAL DRUG STEWARDSHIP

The discovery of antimicrobials is one of the great advances
providers’ desire to adhere to patient’s wishes, even when it
in medicine and their use has substantially reduced morbidity
is not medically appropriate. The most common example of
and mortality worldwide. Unfortunately, with widespread
inappropriate antibiotic use is the prescribing of antibiotics
antibiotic use we have witnessed the emergence of multidrug-
resistant pathogens and reduced efficacy of many of our most
powerful antimicrobials. In addition, we have also recognized
The concept of targeted treatment refers to making a
microbiologic diagnosis promptly and using the most spe-
many adverse effects of antimicrobials, most notably the ris-
ing rates of Clostridium difficile colitis. Further, the cost of for a viral respiratory tract infection.
cific antibiotic that has the best safety profile for the
patient. If multiple broad-spectrum antibiotics are used as
medical care is greatly increased due to overuse of antibiotics
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empiric therapy early in infection then switching to a narrow-
and treating infections caused by resistant organisms. It is
critical that health profession learners understand the key
spectrum antibiotic as soon as possible should be done.
concepts behind antimicrobial stewardship at the time they
learn about microbial pathogens and antimicrobials.
the drugs will not reduce the likelihood of isolating the
causative organism. Further, switching from intravenous
The worldwide problem of antibiotic resistance makes
the need for antimicrobial stewardship evident. The Centers
antibiotics to oral dosing reduces the risk of catheter-
associated infections. The net result of targeted treatment
for Disease Control and Prevention estimates that in the
United States over 2 million infections with multidrug-
is to reduce the ability of antibiotics to select for resistant
resistant pathogens occur each year leading to approximately
20,000 deaths. These pathogens include methicillin-resistant
Limiting the occurrence of adverse effects caused by
Staphylococcus aureus and extended-spectrum β-lactamase
antibiotics is another major goal of antimicrobial steward-
ship. Minimizing the duration of antibiotic use to only as
producing gram-negative rods (e.g., Escherichia coli and mutants present in the bacterial population.
long as clinically indicated is a key intervention since dura-
Klebsiella pneumoniae). Hospital–associated infections,
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mebooksfree.com mebooksfree.com mebooksfree.com tion should have the dose of some antibiotics adjusted 69 mebooksfree.com
many of which are caused by antibiotic-resistant bacteria, are
tion of exposure correlates closely with the risk of many
estimated to cost billions of dollars each year.
types of adverse effects. Patients with reduced renal func-
The basic principles of good stewardship are threefold:
(1) reduce inappropriate use of antibiotics, (2) encourage
based on their estimated glomerular filtration rate.
targeted treatment with narrow spectrum drugs, and
Antibiotic allergies should be identified and explored in
detail. Although reaction to antibiotics may be commonly
(3) limit adverse effects (Table 10–1). Inappropriate
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