Control of bacterial growth

Control of bacterial growth:- Dr. Lamees A. Razzak
Control of growth, means to prevent growth of microorganisms. This control is effected in two basic ways:
(1) by killing microorganisms
(2) by inhibiting the growth of microorganisms.
Bactericidal:- chemical agent to killing bacteria pathogenic and nonpathogenic but not necessary spore when applied to either living tissue or intimate surface.
Bacteriostatic:- agent to inhibiting the growth of bacterial cells.
Disinfectants:- are substances that are applied to non-living objects to destroy microorganisms that are living on the objects.
Disinfection:-The process or act of destroying pathogenic microorganisms. Reducing the number of viable microorganisms present in a sample. does not necessarily kill all microorganisms, especially resistant bacterial spores
Septic:- presence of pathogenic microbes in living tissue.
Aseptic:- absence of pathogenic microbes.
Antiseptic:- chemical agent that destroy or inhibit the growth of microorganism in living tissue.
Sterilization:- a physical or chemical process that completely destroys or removes all microbial life, including spore.
Methods used for sterilization or disinfection:-
Physical agents:-
A- Application of heat:-
Autoclaving (steam under pressure or pressure cooker, moist heat):
Autoclaving is the most effective and most efficient means of sterilization. All autoclaves operate on a time/temperature relationship. These two variables are extremely important. Higher temperatures ensure more rapid killing. The usual standard temperature/pressure employed is 121?C/15 psi for 15 minutes. Autoclaving is ideal for sterilizing biohazardous waste, surgical dressings, glassware, many types of microbiologic media, liquids, and many other things. However, certain items, such as plastics and certain medical instruments (e.g. fiber-optic endoscopes), cannot withstand autoclaving and should be sterilized with chemical or gas sterilants. kills all forms of life including bacterial endospores