Control Of Microorganisms By Chemical Agents

There are many chemical compounds those have the ability to inhibit growth of microorganisms or to kill them. 

Characteristics Of An Ideal Antimicrobial Agent

There is not a single chemical agent which is best for the control of microorganisms for any and all purpose.

Definition Of Terms

The following terms are used to describe the processes and chemical agents employed in controlling microorganisms 


The process of destroying all type of microbial life is termed as sterilization. A sterile object is addressed to an object which is free of living microorganisms. The term sterile, sterilize, and sterilization therefore refer to the complete absence or destruction of all microorganisms and should not be used in a relative sense. An object or substance is sterile and should not be used in a relative sense. An object or substance is sterile or nonsterile; it can never be semisterile or almost sterile.


An agent usually a chemical, that kill the growing forms but not necessarily the resistant spore forms of disease producing microorganisms. Disinfection is the process of destroying infectious agent.


A substance that opposes sepsis, i.e. prevent the growth of microorganisms either by destroying microorganisms or by inhabiting their growth and metabolism. Usually associated with substances applied to the body.


An agent that reduce the microbial population to a safe levels as judged by public health requirements. Usually it is a chemical agent that kill the microbial life by 99.9 %. Sanitizers are commonly applied to inanimate objects and are generally employed in the daily care of equipment and utensils in restaurants, dairies and food plants.

Germicide (Microbicide)

An agent that kills the growing forms just not necessarily the resistant spore forms of germs; in practice a germicide is almost the same thing as a disinfectant, but germicides are commonly used for all kinds of germs (microbes) for any application.


An agent that kills bacteria. Similarly, the terms fungicide, virucide, and sporicide refer to agents that kill fungi, viruses, and spores, respectively.


A condition in which the growth of bacteria is prevented . Similarly, fungistatic describes an agent that stops the growth of fungi. Agents that have in common the ability to inhibit growth of microorganisms are collectively designated microbistatic agents.

Antimicrobial agents

One that interferes with growth and metabolism of microbes. In common usages the term denotes inhibition of growth, and with reference to specific groups of organisms such terms as antibacterial or antifungal are frequently employed. Some antimicrobial agents are used to treat infections, and they are called chemotherapeutic agents.

Selection Of A Chemical Agent For Practical Applications

The major factors that need to be associated in the process of selecting the most appropriate chemical agent for a specific practical application are

Nature Of The Material To Be Treated

A chemical agent that is used to disinfectant utensils, may be quite harmful for skin tissue. Consequently the substrate selected must be compatible with the material to which it is applied.

Type Of Microorganisms

Chemical agents are not all equally effective against bacteria, fungi, viruses, and other microorganisms. Spores are more resistant than vegetative cells. Therefore, the agent selected must be known to be effective against the type of organisms to be destroyed.

Environmental Conditions

Temperature, pH, time, concentration, and presence of extraneous organic material, may all have a bearing on rate and efficiency of antimicrobial action.

Reference: Microbiology by Pelczar

Gaurav Singh

Editor in Chief Medical Microbiology & Recombinant DNA Technology (RDT) Labs - RDT Labs Magazine

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