Chemical antimicrobials

1
Chemical antimicrobials

• 10,000 manufactured today
• About 1,000 routinely used
• Society is obsessed with killing germs to the
  point of being excessive
• Result

2
Qualities of chemical antimicrobials

• Rapid action, even in low concentration
• Water/alcohol soluble, stabile
• Broad spectrum w/o being toxic
• Penetration, sustained action
• Resitance to inactivation
• Noncorrosive, nonstaining
• Sanitizing and deodorizing
• Inexpensive and available

3
Levels of activity
4
Factors that affect activity

• Type of microorganism being treated
• Material being treated
• Amt of contamination
• Exposure time
• Strength/action of germicide
• Appendix C shows procedures for testing
  effectiveness

5
Ways to express strength/concentration

• Dilution
• ppm
• Percent
• Aqueous solutions
• Tinctures

6
(No Transcript)
7
Chemical control - categories

• Halogens
• Phenolics
• Chlorhexidine
• Alcohols
• Hydrogen peroxide
• Detergents soaps
• Heavy metals
• Aldehydes

8
1. Halogens

• Ionic (halide) or nonionic
• Mostly
• Germicidal and sporicidial with long exposure
• Affect protein structure (bonds)

9
1. Halogens

• Chlorine Cl2, hypochlorites (chlorine bleach -
  OCl), chloramines
• In water release hypochlorous acid (HOCl)
• Denaturation of proteins by disrupting disulfide
  bonds
• Can be
• 0.6-1 ppm Cl2 to clean water
• Bleach

10
1. Halogens

• Iodine - I2, iodophors (betadine)
• Denature proteins similar to Chlorine but
  ________________________________
• Broad spectrum microbicide, can be sporicidal
• Milder medical dental degerming agents,
  disinfectants, ointments, topical antiseptic
• Betadine (iodophor) iodine neutral polymer
  allows for

11
2. Phenolics

• Phenol ring (aromatic carbon ring) groups
• Disrupt cell membranes precipitate (denature)
  proteins ________________________________________
  ___________________________
• Lysol
• triclosan- antibacterial additive to soaps
• Mouthwash! (thymol)
• Can be VERY toxic! Not typically used as
  antiseptics.

12
(No Transcript)
13
triclosan
14
3. Chlorhexidine

• Hibiclens, Hibitane
• A surfactant protein denaturant with broad
  microbicidal properties
• Not ______________
• Used as _____________ ____________________________
  ______________________

15
4. Alcohols

• Ethyl, isopropyl in solutions of 50-90 (water
  needed for protein coagulation)
• Act as ______________ dissolving membrane lipids
  and coagulating proteins of vegetative bacterial
  cells and fungi
• Not sporicidal
• Isopropanol rubbing alcohol, but vapors can be
  toxic

16
5. Hydrogen peroxide

• Weak (3) to strong (25)
• Oxidizing agent (steals electrons)
• Produce highly reactive hydroxyl free radicals
  that damage protein DNA while also decomposing
  to O2 gas (bubbles)
• __________________________________________________
  ___________
• Strong solutions are ________________

17
(No Transcript)
18
6. Detergents soaps

• Polar compounds that work as __________
• Quaternary ammonia cpds (_______) act as
  surfactants that alter membrane permeability of
  some bacteria fungi
• Not sporicidal, ineffective against TB,
  hepatitis, pseudomonas
• Soaps- ___________________________________________
  ___________________________

19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
7. Heavy metals

• Solutions of silver mercury kill vegetative
  cells in low concentrations by __________
  proteins
• Metallic salts
• Oligodynamic action
• _______________
• Very toxic to humans
• Not used on broken skin

23
(No Transcript)
24
8. Aldehydes

• Glutaraldehyde formaldehyde kill by alkylating
  protein DNA (-CHO is reducing group)
• Alkylation H on AA is replaced by the aldehyde
  (and crosslinked)
• glutaraldehyde in 2 solution (Cidex) used as
  ________________________________
• formaldehyde - disinfectant, preservative,
  toxicity limits use (formalin is aqueous solution)

25
(No Transcript)
26
Gases aerosols

• Ethylene oxide, propylene oxide,
  betapropiolactone chlorine dioxide
• Strong alkylating agents, ____________
  ____________

27
(No Transcript)
28
Miscellaneous antimicrobials

• Dyes crystal violet, acriflavine
• Acids, bases (alkalies) destroy but some are
  corrosive and hazardous