Chemical Methods Of Bacterial Control

Front 1

Phenols and Phenolics

Back 1

Example: Carbolic acid
Effectiveness: Kills vegetative cells, some fungi, limited effectiveness against spores
Action: Membrane damage & denaturation of enzymes
Exposure time: effect is immediate and persistent
Use: In combo with halogens, detergents. Used on surfaces, instruments, skin.
Notes: Irritates skin, odorous

Front 2

Bisphenols

Back 2

Example:
Effectiveness: Used against G+ bacteria such as Staph & Strep
Action: Membrane damage
Exposure time: Immediate & persistent
Use: Hand soaps and skin lotion disinfectant
Notes: Can cause neurological damage

Front 3

Halogens - Chlorine

Back 3

Example: hypochlorite, bleach
Effectiveness: Kills vegetative cells, viruses and fungi
Action: Oxidizing agent inhibits proteins
Exposure time: Immediate effect
Use: Purification of pools, drinking water, sewage, dairy equipment, eating utensils & glassware, household use

Front 4

Halogens - Iodine

Back 4

Example:
Effectiveness: Kills vegetative cells, viruses, fungi, and some spores when in high concentration
Action: Oxidizing agent inhibits proteins
Exposure time: 60 seconds kills bacteria
Use: tincture (with alcohol), wound dressings, preoperation prep, skin disinfectant
Notes: Irritating odor, residue

Front 5

Alcohols

Back 5

Example: Isopropyl
Effectiveness: Kills vegetative cells and viruses
Action: Membrane damage and enzyme denaturation
Exposure time: 10-15 minutes lasts for a 70-80% solution. Volatility of medium gives a limited effectiveness time wise
Use: Skin, surfaces, thermometers

Front 6

Heavy Metals

Back 6

Example: Hg (mercury), Ag (silver), As (arsenic), Zn (zinc), Cu (copper)
Effectiveness: Kills some vegetative cells and viruses
Action: Denatures enzymes
Exposure time: Effectiveness lasts as long as metal is in contact
Use: Hg - skin & mucous membranes; Ag - infant eye drops against gonorrhea; As - protozoan infections; Zn - fungal infections; Cu - algal infections
Notes: most also toxic to human tissues, so use is limited

Front 7

Surface active agents

Back 7

Example: Soaps, detergents
Effectiveness: kills bacteria, fungi and some viruses; in combo with water can remove pathogens from surfaces
Action: anionic detergents damage membranes, cationic detergents also denature enzymes. Mechanical removal by emulsifying agents
Exposure time: 10-30 minutes effectiveness
Use: Food sanitizers, skin, utensils, cleaning

Front 8

Aldehydes

Back 8

STERILIZER

Example: Formaldehyde and glutaraldehyde
Effectiveness: Kill bacteria and viruses, spores with prolonged exposure
Action: Inactivates proteins
Exposure time: Immediate for bacteria and viruses. In 2% solution, spores are denatured in 3-18 hours
Use: Embalming, specimen preservation. Sterilization of utensils
Notes: Leaves residue, heavy odor, can penetrate tissue

Front 9

Organic acids

Back 9

Example: Sorbic acid, benzoic acid
Effectiveness: create acidic pH that inhibits fungi
Action: Acid pH inhibits metabolic functions
Use: as antifungal in cosmetics, food

Front 10

Gaseous sterilizers

Back 10

STERILIZER

Example: Ethylene oxide
Effectiveness: 100% effective
Action: Protein denaturation
Exposure time: 1-2 hours at 60 degress C for small loads. Up to 12 hours for large loads
Use: Sterilization of plastic and rubber medical supplies
Notes: Carcinogen, issues with exposure to humans. Expensive. Slow, expensive, leaves residue

Front 11

Oxidizing agents - ozone and hydrogen peroxide

Back 11

Effectiveness: most useful against anaerobic organisms (catalase in aerobic organisms neutralizes H2O2)
Action: Pulls away electrons from molecules to destabilize molecules
Exposure time: .3-6% solution is effective disinfectant for 5-10 minutes
Use: Deep wounds, non-living surfaces, contact lenses, surgical implants

Front 12

Oxidizing agents - peracetic acid

Back 12

STERILIZER

Effectiveness: 100%
Action: Oxidiation of molecules
Exposure time: 5 minutes for vegetative cells; 30 minutes for endospores and viruses
Use: disinfection of food processes and medical equipment