chemical agents in microbial control Flashcards
who first used phenol
joseph lister
does phenol sterilze
no
if it doesn’t sterilize, what does phenol do
disinfects and antisepsis
T or F: phenol is used today
false; it is not used today
why isn’t phenol used today
it irritates the skin and has a bad odor
what is used today instead of phenol
derivatives of phenol, called phenolics
how are phenolics formed
formed by the addition of an organic group or halogen to phenol
what is a bisphenolic
two phenolics covalently linked together
what kind of bond joins two phenolics to form a bisphenolic
covalent bond
mode of action of phenolics
they disrupt membranes and denature proteins
T or F: phenolics kill mycobacterium
true! and not many agents can do this
T or F: phenolics are active in the presence of organic material
true
T or F: phenolics are not good for surface disinfection
false; they persist on surfaces for a long period of time + are commonly used in labs and hospitals
T or F: phenolics smell good
false; they smell bad
do alcohols sterilize
no
if they don’t sterilize, what do alcohols do
disinfection and antisepsis
what are alcohols active against
bacteria and fungi
mode of action of alcohols
denature proteins, dissolve membrane lipids
name the two most commonly used alcohols
ethanol and isopropanol
which is better: ethanol or isopropanol. list 3 advantages of the better one
isopropanol is better in terms of activity against microbes, it’s less volatile, and it’s cheaper
T or F: alcohols evaporate and react quickly
true
how long should you let alcohol soak to disinfect something
10-15 min
what is a tincture
formed when another chemical is mixed with alcohol
T or F: tinctures work better than if the alcohol was dissolved in water
true
list 4 halogens
I, F, Cl, Br
mode of action for halogens
they oxidize cell constituents and act as protein synthesis inhibitors
does iodine sterilize
no
if it doesn’t sterilize, what does iodine do
antiseptic
what is iodine effective against
a wide range of bacteria, many spores (at high concentrations of I2), various fungi, and some viruses
what two forms of iodine are used for medical purposes
as a tincture or an iodophore
what is an iodophore
iodine with an organic molecule
two advantages of iodophore
non staining, and it allows for a slow release of iodine so it’s less irritating to the skin
list two common commercial preparations of iodine
betadine and isodine
list two forms of chlorine
Cl2 and ClO2
what is Cl2 used for
to treat drinking water, swimming pools, and wastewater in sewage treatment
what is ClO2 used for
to disinfect large spaces and it can be combined with other chemicals
give an example of a product formed when ClO2 binds with another chemical
NaOCl (household bleach)
what is the formula for household bleach
NaOCl
does chlorine sterilzie
no
if it doesn’t sterilize, what does chlorine do
disinfectant
what is chlorine effective against
bacteria and fungi. NOT spores
give an example of chlorine being used at the individual level
halazone tablets are used to make drinking water safe
what is bromine used for
to disinfect hot tubs
why would bromine be used instead of chlorine
it evaporates more slowly at high temperatures
does bromine sterilzie
no
if it doesn’t sterilize, what does bromine do
disinfects
what is fluorine used for
can be used in drinking water and toothpastes
list 3 oxidizing agents
peroxides, ozone, peracetic acid
mode of action for oxidizing agents
release oxygen radicals that microbes are sensitive to
give an example of a peroxide
hydrogen peroxide
what is hydrogen peroxide used for
household cleaners, contact lenses
does hydrogen peroxide sterilize
yes BUT it must be heated gaseous hydrogen peroxide
what is heated gaseous hydrogen peroxide used for
used to sterilize the atmosphere and surfaces
what is ozone used for
treat drinking water
formula for ozone
O3
what is peracetic acid used for
used in medical facilities and food processing plants to sterilize equipment
does peracetic acid sterilize
yes
what forms can peracetic acid be used in
liquid or vapour
list 5 heavy metal ions that are used
arsenic, zinc, copper, mercury, silver
mode of action for heavy metal ions
they combine with sulfur atoms present in certain amino acids that make up proteins, which denatures them
which heavy metal ion is used as an antiseptic
silver
describe the uses of silver as an antiseptic
can be used in surgical dressings, burn creams, catheters, clothing, and in paper
what is copper used for
controls algal growth in fish tanks, swimming pools, and reservoirs. Also used on the hulls of boats
what are copper, zinc, and mercury used for
used to control mildew in paint
do heavy metal ions sterilize
no
what are quaternary ammonium compounds
derivatives of the ammonium ion
mode of action of quaternary ammonium compounds
disrupt membranes and denature proteins
do quaternary ammonium compounds sterilize
no
if they don’t sterilize, what do quaternary ammonium compounds do
disinfect and antiseptic
what are quaternary ammonium compounds effective against
bacteria, fungi, enveloped viruses
T or F: quaternary ammonium compounds kill nonenveloped viruses
false; they can only kill enveloped viruses
when might quaternary ammonium compounds be used
hospitals to disinfect, or as a skin antiseptic
name two common aldehydes
glutaraldehyde and formaldehyde
mode of action of aldehydes
forms covalent crosslinks with several organic functional groups in order to inactivate nucleic acids and denature proteins
which functional groups will aldehydes form covalent cross links with in order to denature proteins
NH2 OH COOH and SH
which form of formaldehyde is commonly used
formalin
what is formalin
it’s formaldehyde dissolved in water to make a 37% solution
what percentage of formalin is formaldehyde? what is the remaining component
37%, rest is water
what is formaldehyde used for
embalming + as a disinfectant for surgical instruments
does formaldehyde sterilized
yes
in what conditions can formaldehyde sterilize
if left for 24 hours using an 8% solution
list some disadvantages of formaldehyde
potential carcinogen, long term exposure in air or on skin can lead to respiratory problems and skin irritation, produces irritating fumes and bad odor, leaves a residue
what percentage of glutaraldehyde is used as a disinfectant
2%
T or F: glutaraldehyde can kill mycobacteria
true
is glutaraldehyde a sterilant
yes
in what conditions is glutaraldehyde a sterilant
if left for 3-10 hours
advantage of glutaraldehyde
non corrosive
disadvantages of glutaraldehyde1
gives off irritating fumes and leaves a residue
what is glutaraldehyde used for
used as a disinfectant for lab and hospital equipment
give an example of a gaseous agent
ethylene oxide
what is ethylene oxide effective against
all bacteria and bacterial spores, but requires a lengthy exposure time
mode of action of ethylene oxide gas
cross links functional groups in proteins and nucleic acids
T or F: to be a sterilant, ethylene oxide gas requires a lengthy exposure time
true
uses of ethylene oxide gas
hospitals and dental offices (gas autoclave), can be used to treat heat sensitive materials
3 advantages of ethylene oxide gas
sterilizing, highly penetrating, and it sterilizes without heat
4 disadvantages of ethylene oxide gas
highly explosive, poisonous, carcinogen, takes a long exposure time to treat items
list 3 biological methods of control
predacious bacteria
bacteriophages
products of microorganisms (ie bacteriocins)
what agents can kill mycobacterium
phenols, glutaraldehyde
which agents sterilize
heated gaseous hydrogen peroxide, peracetic acid, formaldehyde, glutaraldehyde, ethylene oxide gas
