E2L15: Chemical Methods - Protein Coag. Flashcards
What are the 2 ways to denature proteins?
1) protein coag
2) non-specific chemical combination (oxidation or alkylation)
What are the 6 MOAs of chemicals for the control of microorg?
1) Denaturing proteins (2 ways)
2) Disrupt Phospholipo-Protein Membranes (cell membrane)
3) Suppress Cell Wall Synthesis (murein)
4) Antimetabolites (non/competitive inhibitors)
5) Inhibit Protein Synthesis (affect RNA: ribosomes/RNA polymerase)
6) Inhibit Nucleic Acid Synthesis
Protein coagulants: broad or narrow spectrum? Disinfect or sterilize?
- Very broad spectrum, b/c every living thing has proteins, can even be used for fungi, protozoa, viruses, helminthes, etc
- most are DISINFECTANTS
What does it mean to treat something “systemically”?
Your treatment would have to enter the patient’s blood stream.
What do protein coagulants do?
- destroys 3D protein structure, H bonds, disulfide bonds
- causes protein to solidify
- destroys enzymes –> CIDAL
- AKA “protoplasmic poisons”
What is protoplasm made out of?
Proteins, so protein coag will kill anything w/ protoplasm in it –> very broad spectrum
Do humans take protein coagulants externally or systemically?
EXTERNALLY, b/c we have protoplasm!!! If taken systemically, they would denature all of our proteins!!! 😱
Name some broad groups of chemical protein coagulants from the lecture notes.
1) alkalies (bases: NaOH/KOH), acids (HCl, nitric, sulfuric)
2) phenols
3) chlorhexidine
4) salts of heavy metals
5) alcohols
Alkalies (NaOH/KOH) and acids (HCl, nitric, sulfuric) are typ. too strong to use routinely. What are some routine use examples?
1) NH4OH (labeled “contains ammonia) –> gen. disinfectant
(floors)
2) Benzoic acid (as is or salt-form) –> salts in sodas
3) Proprionic acid –> calcium proprionate (salt) –> anti fungal (preservative) in bread
Alkalies and acid MOA?
PROTEIN COAG
Some salts of Benzoic Acid are used in Diet Sodas. Why? What are the 2 salts mentioned in lecture? What brand uses which salt?
- salts are soluble
- potassium benzoate + sodium benzoate
- diet pepsi and diet coke respectively
What is an research use example for an alkalie chemical?
NaOH to dissolve the shell of nematodes, so that the eggs can be harvested (not sure if you really need to know but, it’s in the lecture notes)
What does the general structure of a phenol look like?
OH group + benzene ring
Phenols are intermediate in effectiveness. What are some advantages and disadvantages of phenols? Disinfect/sterilize?
ADV: effective in organic matter, strongly microbiocidal to veggies (inclu TB), analegsic (pain killing, ex: cold sore mouth washes)
DIS: not reliably sporicidal (DISINFECTANT), not effective for Hep B, caustic (burns), accumulates in environ (+ keeps working)
What is a simple phenol also known as? What are some applications of phenols? MOA?
- AKA Carbolic Acid
- 1st surgical disinfectant (Joseph Lister in Civil War disinfected his counters to prevent Staph infections)
- Used today as PRESERVATIVE in some vaccines (pneumonia), disinfect ear for ear tubes
What’s used as a preservative in pneumonia vaccines?
Carbolic acid (simple, plain phenol)
What are cresols? What’s their MOA?
- methylated phenols (ortho, meta, para)
- protein coag
- Lysol USED to have cresols
- (good against TB)
Which is more soluble? Phenols or cresols?
- phenols are more soluble b/c cresols have an extra methyl group, making them less soluble
Cresols need ___ to keep them suspended.
- emulsifying agents
- these can be irritating tho
Cresols (or its emulsifying agent) can source from…?
Get it from distilling Coal tar
What’s an example of a cresol?
Creolin!
- dark brown/tan color
- good to use in animal quarters (horse stables), disinfecting/cleansing, but stays in environment
What are o-phenylphenols? MOA?
- ex: of phenol
- protein coag
- used in disinfectant sprays
- McKesson = o-phenylphenols + 59% alcohol
- for hard surfaces @ 25C
What do o-phenylphenols kill? What doesn’t it work on?
- Kills Mycobacterium
- Doesn’t work on Hep
What is hexachlorophene? MOA?
- ex: phenol
- USED TO BE used in 3% soln in shampoo, antimicrobial soaps + baby powders
- has residual action, BUT!!! can be absorbed in thru skin into circ. sys and be NEUROTOXIC!!! 😱
- might be seen in 0.1% as a preservative
Did hexachlorophene get taken off of the OTC market?
YES!!! In 1972, hexachlorophene killed 40 babies!!! WTF!!! 😱
What is an example of a hexachlorophene? Can hospitals get hexachlorophenes?
- ex: Phisohex (hand scrubs for surgeons, b/c staph/strep both G+ and big problems in hospitals)
- hospitals can get them, yes.
What is Phisohex?
An example of a hexachlorophene, used in hospitals as surgeon’s hand scrub
Triclosan replaced what other phenol product?
Hexachlorophene
Where can Triclosan be found in?
Shampoos, soaps, kitty litter, also in some toothpastes as an anti-gingivitis active ingredient
How common is triclosan? What does triclosan disrupt in the body? What’s the MOA?
- used commonly
- endocrine disrupter (disrupts hormone)
- protein coagulation
What can develop resistance to Triclosan? (2)
- Pseudomonas aeruginosa, 15X more resistant than other bacteria
- Acetinobacteria also
What is Cresyl Acetate an example of? MOA? What’s it used for?
- ex: of a phenol
- protein coag
- used as an antiseptic for mucus membranes (ear, nose, throat)
What’s a substitute for hexachlorophene?
- chlorhexidene
- but, triclosan is also trying to replace hexachlorophene
What is Chlorhexidene?
- ex: of phenol
- used common in med. field, surgical hand scrub
- GOOD residual action (sticks, but not absorbed deeply)
- typ 4% soln + 4% isopropyl alcohol
- also becoming GOLD STANDARD, just $$$
What’s has chlorhexidene as its active ingredient?
- ex: Hibiclens
- -> used for decolonize patients if MRSA (to have less sores)
Talk about MRSA a bit.
- from 1-2% up to 42% of ppl have MRSA on skin
- hospital MRSA is more resistant
- hibiclens decolonizes skin to get less sores
What is the best choice chemical to disinfect IV catheters before insertion?
2% chlorhexidene b/c has good residual action
Describe salts of heavy metals as a whole.
- low activity as whole (b/c inactivated by proteins)
- forms scab over wounds, infections fester underneath
- irritating (slow healing)
- some chemicals poisonous (mercury!!!)
What are some examples of salts of heavy metals?
- mercuric bichloride (no longer in use, b/c Hg)
- thimerosal (aka merthiolate, has Hg)
- silver nitrate (AgNO3)
- argyrol
- silver sulfadiazine
- zinc (zinc oxide/zinc chloride)
- copper
Do we still use Mercuric Bichloride (HgCl2)? What was its history?
- no!!! accumulates in environment, also toxic
- historically used as disinfectant in 1-2% soln
What is Thimerosal? What’s it also known as? What’s it used as? Is it still on OTC market?
- aka Merthiolate
- used as antiseptic; used as preservative in vaccines; process vaccines, but removed b4 use – (end up w/ nothing left or little in vaccine)
- removed from OTC market 1998
- moa: protein coagulation, is a salt of heavy metal
What was a problem with Thimerosal and Vaccines?
- used to contaminated MULTIDOSE vaccines when needle touched skin and staph would infect skin
What’s Silver Nitrate (AgNO3)? What is it used to prevent? What’s it used for in hospitals?
- ex: of salt of heavy metal
- used to prevent ophthalmia neonatorum (child blindness during childbirth)
- used in hospitals to disinfect urinary catheters b4 use
What’s the DOC to prevent child blindness (ophthalmia neonatorum)?
Erythromycin
What 2 organisms could cause ophthalmia neonatorum?
- Neisseria gonorrhea
- Chlamydia trachomatis
- -> happens when baby picks up org when going thru birth canal + attaches to eyes
What is Argyrol? MOA? Argyrol = X + Y? How effective is it? What’s it used for?
- ex: of salt of heavy metal
- protein coag
- argyrol = silver + protein (gelatin)
- not that effective
- colloidal used for 5-20% soln
- may be used as preservative in ophthalmic eye drugs
When was Argyrol used for? What was it used for before?
- During WW2, lotsa ppl had SEX (SIMS woo-hoo noise)
- was used up to 1940’s to prevent STD’s, where antibiotics were all the rage
What is Silver Sulfadiazine? MOA? What’s it used for? What’s it the DOC for?
- ex: of salt of heavy metal, ex: antimetabolite (sulfa drug)
- MOA: protein coag + antimetabolite
- used for BURN patients dressings, b/c deadly resultant infections
- also ex: of synergism b/c silver sulfadiazine = silver (heavy metal) + sulfadiazine (sulfa drug)
What is Zinc? What are some examples of Zinc? What’s it used for? What’s it used in? MOA?
- ex: of salt of heavy metal
- ex: Zinc oxide, Zinc chloride
- antifungal
- preservative in mouth wash
- MOA: protein coag
What is Copper? What’s it used as? Is it released quickly? MOA?
- ex: of salt of heavy metal
- antifungal (copper socks for feet)
- released quickly
- MOA: protein coag
What’s the MOA of alcohols? What are some examples of alcohols?
- MOA: protein coag
- ex: methanol, ethanol, isopropyl, benzyl
What’s a general rule about alcohols regarding their molecular weight and efficacy? In comparison to chlorhexidine?
- higher MW, higher efficacy of the alcohol
- -> BUT, anything higher than isopropyl not soluble in H2O, can’t be used as disinfectant
- not as effective as chlorhexidine
Methanol???
- not very effective
- not really used a disinfectant
What’s ethanol?
- ex: an alcohol
- used commonly as disinfectant (ex: rubbing alcohol 70%)
- “standard test” - test out @ [normal] + [lower]
- -> 70% works well against E. coli, but 35% doesn’t (unlike isopropyl)
[concentration] / 70% / 35%
ethanol / + / -
isopropyl / + / +
need to test different concentrations b/c adding alcohol amt to a certain size load will change the concentration, and thus the efficacy of the alcohol
Say you have a blood spill (~100ml blood) and want to use 100ml of 70% ethanol to disinfect it. What’s the adjusted [ethanol] and is it effective?
- adjusted [] = 35%
- no longer effective!!!
- -> important to test out [different]’s!!!
What’s isopropyl alcohol? What [isopropyl] work for E. coli?
- ex: alcohol, (duh, wtf, you so silly)
- smelly
- both 70% + 35% work against E. coli
What’s Benzyl alcohol? Is it soluble? What’s it used in? Why is it not good for newborns (aka neonates)?
- ex: alcohol (lmao, stfu)
- not very soluble
- used as preservative in IV soln
- TOXIC to neonates b/c they don’t have the proper enzymes to break benzyl alcohol down
What are some of the downsides to alcohols?
- evaporates quickly, can’t really apply it for the 0-15 min
- not sporicidal, even if left on indef.
Why do CVS shots use alcohol to disinfect the skin instead of chlorihexidine?
alcohols are cheaper, cost is a big factor, lmao
Which of the following is used for surgical hand scrubs?
a) cresyl acetate
b) chlorine bleach
c) chlorhexidine
d) tincture of iodine
e) ethanol
c) chlorhexidine
but Phisohex could also be an example too
These agents are also usually sterilants.
a) bactericide
b) virucide
c) sporicide
d) disinfectant
e) germicide
c) sporicide, which is basically the definition of a sterilant, lmao
