Antibacteril protocols 7.3 Flashcards
What are antisepsis? selected based on?
Agents that reduce the number of microbes on skin surfaces.
*selected for safety and efficacy
1) alcohols have excellent activity against?
2) can dry the skin surface because?
3) inactivated by?
4) what should you do before applying alcohol?
- 1) excellent activity against all groups of organisms except spores
- 2) are nontoxic but can dry the skin surface because they remove lipids
- 3) do not have residual activity and are inactivated by organic matter
- 4) surface of the skin should be cleaned before alcohol is applied
Iodophors are excellent ___ agents
antiseptic
Iodophors activity is similar to? inactivated by? frequently used with?
have a range of activity similar to that of alcohols.
• are slightly more toxic to the skin than alcohol
• have limited residual activity
• inactivated by organic matter.
• Iodophors and iodine preparations are frequently used with alcohols
1) Chlorhexidine has broad ____ activity
2) kills organisms at a slower rate than?
3) its activity persists or ends quickly
4) what decreases its effectiveness?
1) broad antimicrobial activity
2) kills organisms at a much slower rate than alcohol
3) Its activity persists
4) organic material and high pH levels decrease its effectiveness
Parachlorometaxylenol(PCMX) is limited to?
2) is nontoxic or toxic?
3) used in what type of products?
1) is limited primarily to gram-positive bacteria
2) is nontoxic and has residual activity
3) used in hand washing products
Triclosan
1) is active agaisnt?
2) commonly found in what products?
3) may cause developement of?
4) commonly used or phased out
1) active against bacteria but not much else
2) common antiseptic in deodorant soaps and toothpaste
3) May cause the development of antibiotic resistant strains of bacteria
4) Is BEING phased out
Antibacterial spectrum
Range of activity of an antimicrobial against bacteria
Broad-spectrum antibacterial drug
can inhibit a variety of gram-positiveand gram-negative bacteria
narrow-spectrum antibacterial drug
is active against a limited variety of bacteria
Bacteriostatic antibiotic
Antibiotic that inhibits the growth of bacteria but does not kill
Bactericidal antibiotic
Antibiotic that kills bacteria
Minimum inhibitory concentration (MIC)
The lowest antibiotic concentration that inhibits the growth of the bacteria is the MIC
Minimum bactericidal concentration (MBC)
The lowest antibiotic concentration that kills 99.9% of the population is referred to as the MB
Antibiotic combinations
Combinations of antibiotics to (1) broaden the antibacterial spectrum for empirical therapy, (2) prevent emergence of resistant organisms during therapy, and (3) achieve a synergistic killing
Antibiotic synergism
Combinations of two antibiotics that have enhanced bactericidal activity when tested together compared with the activity of each antibiotic
Antibiotic antagonism
Combination of antibiotics in which the activity of one antibiotic interferes with the activity of the other (e.g., the sum of the activity is less than the activity of the most active individual drug)
β-Lactamase
An enzyme that hydrolyzes the β-lactam ring in the β- lactam class of antibiotics, thus inactivating the antibiotic
Pasteurization
the heat treatment of milk or other liquids to reduce its total number of microorganisms
Pasteurization
1) created by?
2) first used for?
3) reduces _____ load? this increases?
4) does NOT kill
1) Louis Pasteur
2) First used for controlling the spoilage of wine
3) reduces microbial load. This decreases spoilage and INCREASES shelf life
4) does not kill all organisms and therefore does not sterilize
Pasteurization may not kill all organisms, but its does kill all organisms such as?
kills all known pathogenic bacteria that can be transmitted in milk
**tuberculosis, brucellosis, Q fever, and typhoid fever
How do you achieve pasteurization?
the liquid is brought to 71°C for 15 seconds OR even higher temperatures for shorter time periods
**then liquid is rapidly cooled-flash pasteurization
Milk can also be pasteurized by heating it in large vats at what temp?
63–66°C for 30 min
What is common mechanism of antibiotic activity?
Inhibition of Cell Wall Synthesis
Most common cell wall inhibiting antibiotics are classififed as?
β-lactam antibiotics; named this because they share a common β-lactam ring
structure
*Ex: penicillins, cephalosporins, cephamycins, carbapenems, monobactams, β-lactamase inhibitors
Target penicillin-binding proteins (PBPs) that are responsible for?
peptidoglycan cross-links
Disruption of peptidoglycan synthesis triggers autolysins that degrade?
existing cell wall, thus killing the bacterium (bacteriocidal)
*Bacteria can become resistant to β-lactam antibiotics by? (3)
(1) decreased concentration of the antibiotic at the cell wall target site
(2) decreased binding of the antibiotic to the PBP
(3) hydrolysis of the antibiotic by bacterial enzymes, β-lactamases
The basic compound for penicillins is obtained from a culture of mold called? Why used so much?
Penicillium chrysogenum
*Used bc they are highly effective with extremely low toxicity
If Penicillium chrysogenum mold is grown by fermentation, large amounts of ______ are produced?
6- aminopenicillanic acid are produced
Modification of 6-aminopenicillanic acid from penicillium mold increases resistance to
stomach acids, increases absorption in gut, increases resistance to penicillinase, increases spectrum of activity that includes gram-negative bacteria
Penicillin G is inactivated or resistant to gastric acids?
is inactivated by gastric acid; thus it is used mainly as an intravenous drug
Penicillin V is inactivated or resistant to gastric acids?
is more resistant to acid and is the preferred oral form for the treatment of susceptible bacteria
