C.1. General considerations of antimicrobial therapy. Disinfectants and antiseptics Flashcards

1
Q

what does antimicrobial therapy do?

A

kills or inhibits the growth of microorganisms (bacteria, viruses, fungi, protozoans)

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2
Q

what are the characteristics of antibiotic therapy?

A
  1. directed against the cause of the disease
  2. antimicrobial activity + sufficiently high concentration at the site of infection
  3. microbes respond to the Ab
  4. permanent interference with the environment
  5. the most effective and least toxic drug has to be used
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3
Q

give 5 consideration in antibiotic choice and therapy

A
  1. spectrum of action
  2. site of infection (degree of penetration)
  3. pharmacodynamics and pharmacokinetic properties
  4. dosage
  5. adverse effects
  6. presence of renal or hepatic failure
  7. drug interactions
  8. cost
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4
Q

what are the types of antimicrobial therapy?

A
  1. empiric therapy
  2. definitive therapy
  3. prophylactic therapy
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5
Q

what is empiric therapy?

A

treatment is given based on clinical presentation and experience. broad-spectrum antimicrobial agents

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6
Q

what is definitive therapy?

A

based on microbiological results and/or sensitivity tests. narrow antibiotic spectrum.

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7
Q

what is prophylactic therapy?

A

administration of antimicrobial agent for preventing infection prior to clinical presentation.

classified as either pre-exposure prophylaxis or post-exposure prophylaxis

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8
Q

what do bacteriostatic agents do?

A

inhibit the growth of microorganisms

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9
Q

what do bacteriocidal agents do?

A

kill microorganisms within a short period of time.

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10
Q

what is the minimum inhibitory concentration (MIC)?

A

the lowest concentration that inhibits the growth of the organism.

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11
Q

what is the minimum bactericide concentration (MBC)?

A

the lowest concentration that kills 99.9% of the organisms

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12
Q

why are immunocompromised patients given bactericidal agents rather than bacteriostatic?

A

cause their host immunity cannot achieve the final elimination of the weakened organisms.

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13
Q

what is a concentration-dependent antibacterial activity?

A

killing action increases proportionally above the MIC. Requires high-dose administration, once daily.
ex. Aminoglycosides

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14
Q

what is a time-dependent antibacterial activity?

A

killing action continues as long as the drug serum concentration is maintained 40-60% above the MIC.
Requires continuous administration or multiple doses daily.

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15
Q

example for Ab with synergistic effect?

A

aminoglycosides +cell wall active agent
sulfonamide +trimethoprim
beta lactam+ beta-lactamse

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16
Q

when do we use an extended antimicrobial spectrum Ab?

A

polymicrobial infections

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17
Q

when is Ab given in combination to prevent the development of resistance?

A

Tuberculosis

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18
Q

what is disinfection?

A

removal of actively dividing microorganisms. only reduce the number of potential pathogens

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19
Q

what is sterilization?

A

complete elimination of all viable microorganisms.

20
Q

what is Asepsis?

A

state of being free from disease-causing microorganisms

21
Q

what is Antisepsis?

A

the process whereby the risk of medical infection is reduced

22
Q

what is a disinfectant compound?

A

compound that is used to kill microorganisms in an inanimate environment

23
Q

what is an antiseptic compound?

A

compound that is used to inhibit bacterial growth both in-vitro and in contact with the surfaces of living tissues

24
Q

what effective Alcohol skin disinfectants do we have?

A

Ethanol 70%

Isopropanol 70-90%

25
what is more effective- ethanol or isopropanol?
isopropanol | but more toxic
26
what are the effects of Alcohol as disinfectants?
denature microbial proteins (bactericidal effect) | removal of lipids from skin surfaces
27
what is Povidone-iodine?
halogen
28
when is Povidone-iodine (iodophor) used?
as a pre-operative skin antiseptic
29
what is Hydrogen peroxide (H₂O₂)?
an Oxidizing agent
30
what is Hydrogen peroxide used for?
mouth wash, for cleansing wounds, and for disinfection of contact lenses.
31
what are the advantage and disadvantages of alcohol?
adv: no material damage dis: inflammable
32
what are the advantages of oxidizing agents?
wide spectrum, bactericidal, virucidal and fungicidal
33
what does H₂O₂ do?
release of molecular oxygen is antimicrobial
34
list chlorinated phenols
chlorhexidine phenol cresol
35
when do we use chlorinated phenols (chlorhexidine)?
in-hospital scrub routines to cleanse skin sites not to be used during middle ear procedures (severe ototoxicity)
36
what do chlorinated phenols do?
they strongly adsorb to bacterial membranes, causing leakage of small molecules active against gram + cocci and mycobacteria, variable activity against fungi and viruses.
37
what are Octenidin dihydrochloride & invert soaps?
cationic surfactant
38
what are invert soaps?
class of synthetic detergents in which the surface-active part of the molecule is the cation
39
what is Octenidin dihydrochloride active against and what is it used for?
active against gram + and gram - bacteria | used as antiseptic prior to medical procedures, including on neonates
40
when is mercury used as a disinfectant?
on the skin, good antifungal effect
41
which disinfectants have the widest spectrum?
Aldehydes--> Formaldehyde.
42
what are the advantage and disadvantages of aldehydes?
adv: bactericidal, sporicidal, virucidal, fungicidal dis: very irritable
43
what are the characteristics of an ideal disinfectant?
1. effective at ↑ dilution 2. it does not damage tissues 3. odorless 4. stable 5. water-soluble
44
what is Spaulding's classification?
classification of medical equipment/devices and required level or processing
45
division of Spaulding's classification
critical semi-critical noncritical