Microbio Lecture 13
Terms
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- Disinfectant
- agent for destroying pathogens on inanimate objects
- Antiseptic
- prevention of infection on living tissue
- Antisepsis
- destroying of pathogens on living tissue
- Bactericidal
- kills microorganisms
- Bacteriostatic
-
prevents further growh/division of microorganisms
*chloramphenicol - Aseptic
- free of contamination
- Degerm
- removal of microorganisms from a surface
-
Phenolic compounds
what does it do?, 1 example -
- denatures proteins
- reduces surface tension
Examples: Hexylresorcinol (sucrets)
- cresols: derivatives of phenols that are safer and more germicidal - Hexylresorcinol
-
phenolic compound
SUCRETS - Cresols
-
phenol derivative
safer to use
more germicidal - Bisphenols (3 examples)
-
two phenols
- Hexachlorophene in pHisohex: popular but gave brain damage
- Orthophenyl phenol in Lysol
- Trichlosan: broad specturm antimicrobial in soap, toothpaste, sponges, plastics -
Chlorine
what is it used for? why? how is it effective? 3 examples -
Halogen: 7 e's
inexpensive, used in water supply
get rid of microbes expect spores
-changes membrane structure: leakage
-strong oxidizing agent: inactivates enzymes
- sodium hypochlorite 5% household bleach
Calciumhypochlorite: chlorinated lime for pools
Chloramines: organic compounds that have Cl, more stable than hypochlorite -
Iodine
2 examples, what does it do? -
better than Cl
-tincture of iodine 2% iodine/NaI in EtOH
Iodophors (betadine): iodine/detergent complexes which release iodine over long period of time
- halogenates tyrosine on proteins -
Heavy metals
What do they react with? 4 examples -
Hg, Cu, Ag
react with -SH damages enzymes: cystine and methianine
AgNO3 drops for N. gonorrheae
CuSO4: fungicide and algicide
Hg: effective for microbes but bad for host
SeleniumBromide: fungicide found in shampoo -
Alcohols
What do they do? which concentration is more effective? 3 examples -
denatures proteins and dissolve lipids
70% more effective than 100% - need water for coagulation of proteins and penetrates beter
-Isopropanol- high bactericidal
- Ethanol- effective against vegetative cells ESPECIALLY MYCOBACTERIA, but not spores
- methanol: too toxic...carcinogenic -
Ethylene Oxide
used for what and how? problems? -
used in hospitals to sterilize
cross links with nucleic acids and proteins
penetrates packing material: plastics, heat sensitive material
bad: highly explosive and toxic, need aeration -
H2O2
how is it effective? -
catalase in living tissues, break down to water and oxygen
- bubbling removes microbes
- superoxide radical of oxygen formed - toxic to microbes
-oxygen inhibits growth of anaerobic organisms - Soaps and anionic detergents
-
soaps: KOH or NaOH combined with fatty acids
- soap kills microbes with alkaline pH 8
- degerms skin surface: emulsify particles and oil and reduce surface tension
- anionic detergents useful as laundry products - negatively charged bacteria repel negatively charged detergents -
Cationic detergents
also called? it effects what? and how?
what is it made out of? -
also called QUATS
- bacteriostatic (esp. G+)
- dissove lipids in cell membranes
- NH4Cl w/ organic radicals and at least one long chain alkyl group -
Regulation of Chemical Control
who regulates disinfectants and antiseptics? -
EPA (environmental protection agency): disinfectants
FDA: antiseptics - Phenol coefficient
-
number rates agent in comparison to phenol
>1, better
<1, worse
-mix dilutions of phenol or test agent with cultures: Staphylococcus aureus or Salmonella typhi
- subcultured every 5' for 2 days
- dilutions that kill after 10' but not 5' used for PC - Use Dilution Test
-
-current standard of analytical chemist
stainless steel cylinder dipped in:
- salmonella choleraesuis
- staph. aureus
- pseudomonas aeruginosa
cylinder dried and dunked in test agent for 10'
effective: no growth, ineff: growth - Hexachlorophene is a:
- bisphenol; in pHisohex: popular but gave brain damage
- Ortho-phenyl phenol is:
- bisphenol; in Lysol
- Trichlosan is a:
- bisphenol; broad spectrum used in soap, toothpaste, plastics, sponges