Chapters 44 Definitions SLO 2.1 Flashcards
Concentration-dependent killing
A property of some antibiotics, especially aminoglycosides, whereby achieving high plasma drug concentration, even briefly, results in the most effective bacterial kill (compare time-dependent killing). (p. 717)
Extended-spectrum beta-lactamases (ESBLs)
A group of beta-lactamase enzymes produced by some organisms that make the organism resistant to all beta-lactam antibiotics (penicillins and cephalosporins) and aztreonam. Patients who are infected by such organisms must be in contact isolation; proper handwashing is key to preventing the spread of these organisms. (p. 716)
Klebsiella pneumoniae carbapenemase (KPC)
An enzyme first found in isolates of the bacterium Klebsiella pneumoniae that renders the organism resistant to all carbapenem antibiotics as well as beta-lactam antibiotics and monobactams. Such organisms produce a serious resistant infection. (p. 716)
Methicillin-resistant Staphylococcus aureus (MRSA)
A strain of Staphylococcus aureus that is resistant to the beta-lactamase penicillin known as methicillin. Originally, the abbreviation MRSA referred exclusively to methicillin- resistant S. aureus. It is now used more commonly to refer to strains of S. aureus that are resistant to several drug classes, and therefore, depending on the context or health facility, it may also stand for multidrug-resistant S. aureus. (p. 716)
Minimum inhibitory concentration (MIC)
A laboratory measurement of the lowest concentration of a drug needed to kill a certain standardized amount of bacteria. (p. 717)
Multidrug-resistant organisms
Bacteria that are resistant to one or more classes of antimicrobial drugs. These include multidrug-resistant Staphylococcus aureus, extended-spectrum beta-lactamase–producing organisms, and Klebsiella pneumoniae carbapenemase–producing organisms. (p. 716)
Nephrotoxicity
Toxicity to the kidneys, often drug induced and manifesting in compromised kidney function; usually reversible upon withdrawal of the offending drug. (p. 711)
Ototoxicity
Toxicity to the ears, often drug induced and manifesting as varying degrees of hearing loss that is likely to be permanent. (p. 717)
Peak
The highest concentration of a drug in the patient’s bloodstream. (p. 717)
Postantibiotic effect (PAE)
A period of continued bacterial suppression that occurs after brief exposure to certain antibiotic drug classes, especially aminoglycosides (discussed in this chapter) and carbapenems (see Chapter 43). The mechanism of this effect is uncertain. (p. 717)
Pseudomembranous colitis
A necrotizing, inflammatory bowel condition that is often associated with antibiotic therapy. Some antibiotics (e.g., clindamycin) are more likely to produce it than others. More commonly referred to as antibiotic-associated colitis or Clostridium difficile diarrhea or C. difficile infection. (p. 722)
Synergistic effect
Drug interaction in which the bacterial killing effect of two antibiotics given together is greater than the sum of the individual effects of the same drugs given alone. (p. 717)
Therapeutic drug monitoring
Ongoing monitoring of plasma drug concentrations and dosage adjustment based on these values as well as on other laboratory indicators such as kidney and liver function tests; this monitoring is often carried out by a pharmacist in collaboration with medical,
nursing, and laboratory staff. (p. 716)
Time-dependent killing
A property of most antibiotic classes whereby prolonged high plasma drug concentrations are required for effective bacterial kill (compare concentration-dependent killing). (p. 717)
Trough
The lowest concentration of a drug in the patient’s bloodstream. (p. 717)
