CHemical Methods of Microbial Control

5. Surfactants

"surface active" chemicals, they reduce surface tension of solvents.--Soaps and Detergents- Soaps have hydrophilic(attract water) and hydrophobic (break up oils). They ARE GOOD DEGERMING AGENTS, but NOT antimicrobial. Detergents are positively charged organic surfactants(disrupt CM). QUATS, are SYNTHETIC DETERGENTS. low level disinfectants. Ideal for many medical and industrial application. EXCEPT: Psudomonas thrives in quats!!!

Antimicrobials

Antibiotics(produced naturally by microorganisms), Semi-Synthetic(Chemicalls modified antibiotics), and Synthetic chemicals (wholly synthetic antimicrobials).--- Typically used for treatment of disease--- Some used for antimicrobial conrol outside body

Chemical Methods

Antiseptics/disinfectants---affect microbes' cell wals, cytoplasmic membranes, proteins, or DNA---effect varies with differing environmental conditions---often more effective against enveloped viruses and vegatitive cells of bacteria, fungi, and protozoa--- less effective against fungal spores, protozoan systs, or bacterial endospores. NINE MAJOR CATEGORIES

7. Aldehydes

Conpounds contain terminal -CHO groups. HIGH-level disinfectant.--- Cross-link fi=unctionsl groups to denature proteins and inactivate nucleic acids. 2% Glutaraldehyde disinfectants and sterilizes. 37% formaldehyde(Formalin) used in embalming and disinfection and sterilization of rooms and indtruments

6. Heavy Metals (Arsenic, Silver, Mercury, Copper, and Zinc)

Heavy metal ions denature proteins. Low level bacteriostatic and fungiastatic agents. Often less toxic alternatives are preferred.-Silver used in surgical dressings, burn creams, and cathetors. 1% silver nitrite to prevent blindness caused by N. gonorrhoeae. Thimerosal used to preserve vaccines. Copper controls algal growth(Indian tradition w/fecal bacteria?)

3. Halogens ( Iodine, Chlorine, Bromine, and Flurine)

Intermediate-level antimicrobial chemicals-- believed to damage enzymes via oxidation or by denaturation-- Widely used in numerous applications(Iodine tablets, iodophores,chlorine treatment, bleach, chloramines, and bromine disinfection).----Iodine=medical uses(betadine), Chlorine=treat water, Bromine= better for hot tubs bc of slower evap at high temps, Fluorine=reduce incidence of dental cavities=disrupts metabolism in plaque biofilm.

Development of Resistant Microbes

Little evidence that products containing antiseptic and disinfectant chemicals ass to human or animal health. --- Use of such products promotes development of resistant microbes.

8. Gaseous Agents

Microbicidial and sporicdial gases used in closed chambers to sterilize items--- Denature proteins and DNA by cross-linking functional groups.---used in hospitals and dental offices---Disadvantages: can be hazardous to ppl, often hughly explosive, extremely poisonous, potentiall carcinogenic. EX: Ethylene oxide, propylene oxide, beta-propiolactone

9. Enzymes

Natural and Artificial Antimicrobial enzymes act against microorganisms. ---Human tears contain lysozyme, which digests peptiglycan cell wall of bacteria. Enzymes to control microbes in the environment: Lysozyme used to reduce the # of bacteria in cheese 2006: Prionzyme can remove prions on medical instruments.

1. phenol and phenolics

compounds derived from phenol molecules that have been chemically modified by the addition of halogens or organiz functional groups such as chlorine. -intermediate to low level disinfectants-denature proteins and disrupt cell membranes-effective in presence of organic matter-remain active for prolonged time-commonly used in health care settings, labs, and homes-have disagreeable odor and possible side effects. EX: lysol, triclosan

2. Alcohols

intermediate-lever disinfectants.- Denature proteins and disrupt cytosplasmic membranes.-bactericidal, fingicidal, and virucidal (enveloped)- NOT effective against fungal spores or bacterial endospores- TINCTURE=solutions of other antimicrobials in alchol- more effective than soap in removing bacteria from hands. EX: isopropanol, ehtanol

4. Oxidizing Agents

peroxides, ozone, and peracetic acid!-- kill by oxidation of microbial enzymes, thereby preventing metabolism. -- High-level disinfectant and sntiseptics. Hydrogen Peroxide can disinfect and sterilize surfaces(NOT USEFUL FOR TREATING OPEN WOUNDS DUE TO CATALASE ACTIVITY). Canadian and European: Ozone treatment of drinking water. Peracetic acid is effective sporocide used to sterilize equipment.