Control of Microbial Growth Flashcards
If the PC of the chemical used is greater than 1, it would indicate that the chemical being tested is more/less effective.
more
test organism for control of microbial growth
staphylococcus aureus
methods of microbial control (2)
physical methods
chemical methods
physical methods of microbial control (5)
heat
cold temperature
desiccation
radiation
filtration
chemical methods of microbial control
use of disinfectant
use of antiseptics
use of antibiotics
applied to nonliving surfaces (used to kill germs on nonliving surfaces).
disinfectant
applied to the body (use to kill microorganisms on skin surfaces).
antiseptic
a medicine (such as penicillin or its derivatives) that inhibits the growth of or destroys microorganisms.
antibiotic
introduced the use of phenol to reduce the risk of infection during operation
Joseph Lister (1867(
phenol derivative include
cresol
xylenols
orthophenylphenol
Contain surfactants
hand soaps
compounds with hydrophilic and hydrophobic parts
surfactants
Break oily substances and coat the droplets to form an emulsion, which can be rinsed away
surfactants
Surfactants are not ____ by themselves
germicidal
compounds that act as surfactants that alter membrane permeability of some bacteria and fungi (Not sporicidal)
quaternary ammonia
antibacterial additives to soaps
quaternary ammonia
phenolic compounds
example of phenolic compounds
triclosan
disrupt cell membranes and precipitating proteins
phenolic compounds
Considered the simple most important step in preventing the spread of many infectious diseases
simple hand washing
___ ___ itself generally does not destroy many organisms; it simply aids in the mechanical removal of soil and grease containing microbes, including most pathogens.
plain soap
Factors Influencing the Effectiveness of Chemical Agents:
(4)
population of microorganisms
volume of inoculum
time of application
concentration of the agent
Chemical control of Microbes
give examples
Halogens
Phenolics
Chlorhexidine
Alcohols
Hydrogen peroxide
Detergents and soaps
Heavy metals
Aldehydes
seldom used as a disinfectant or antiseptic because of its irritating qualities and disagreeable odor
phenol
derivatives of phenol that are reactive even in the presence of organic material; O-phenylphenol
phenolics
especially common example of a bisphenol
Triclosan
broad spectrum, but most effective against gram-positives
Bisphenols
bactericidal to gram-positives and gram-engatives or as components of inorganic and organic compounds
biguanides
iodine or chlorine may act alone or as components of inorganic and organic compounds
halogen
inhibits protein function and is a strong oxidizing agent
iodine
forms the strong oxidizing agent hypochlorous acid, which alters cellular components
halogens
effective anti-septic available as a tincture and an iodophor
iodine
used to disinfect water
chlorine gas
used to disinfect dairy equipment, eaitng utensils, household items, and glassware
chlorine compounds
bactericidal and fungicidal, but not effective gainst endospores or nonenveloped viruses
alcohols
commony used alcohols
ethanol
isopropanol
heavy metals such as silver and mercury are biocidal
heavy metals
may be used to prevent gonorhheal ophthalmia neonatoruml mecurochrome disinfects skin and mucous membranes
silver nitrate
algicide
copper sulfate
surface active agents
soaps and acid anionic detergents
acid-anionic detergents
most resistant microbes
prions
most resistant to least resistant microbes
prions
endospores of bacteria
mycobacteria
cyst of protozoa
vegetative protozoa
gram - bacteria
fungi (incl. most fungal spore forms)
viruses w/o envelopes
gram + bacteria
viruses with lipid envelopes
which chemical agent is fair in endospores and mycobacteria
fair
the best known disinfectant screening test in which the potency of a disinfectant is compared with that of phenol.
phenol coefficient test
phenol coefficient test formula
PC = A/B
A = highest dilution of test chemical that kills the microorganisms after 10 mins but not 5 mins
B = highest dilution of phenol that kills the microorganism after 10 minutes but not 5 minutes
interpretation of PC
PC > 1
disinfectant is more effective than phenol
interpretation of PC
PC = 1
equal effectiveness of two chemicals
interpretation of PC
PC < 1
indicates less effectiveness of testchemical
compute the substance concentration and amount of water given the following ratio
1:70 (lysol to water)
50 ml of solution
50/70*1000 = 714 ul
49.29 ml of water
compute the substance concentration and amount of water given the following ratio
1:80 (lysol to water)
50 ml of solution
50/80*1000=625 ul
49.38 ml of water
