Microorganisms

Antimicrobial efficacy is defined as the logarithmic or percentage difference in viable cell counts between surfaces that are treated with antimicrobial agents versus untreated surfaces. Efficacy of the Antimicrobial agent is determined through a suspension/surface test.
In this test, a controlled inoculum of the challenge organism(s) is placed in suspension with the sample to be tested
In case of surfaces treated with antimicrobial products, the inoculum is spread on treated surfaces in order to determine the elimination efficacy of the antimicrobial product.
The microbe load is then monitored at different intervals of time in order to assess the efficacy of the antimicrobial agent.
This test is one of the ways of determining the microbial elimination potential of chemical disinfectants.
According to US Environmental Protection Agency (EPA), disinfectants are categorised into three types based on their ability to eliminate different Hospital Acquired Infection (HAI) causing microbes. The classification is as follows:
- A. High level disinfectants : Should be effective against viruses and spores in a relatively short period of time
- B. Intermediate level disinfectants : Should be effective against Mycobacterium tuberculosis and all fungi.
- C. Low level disinfectants : Should be effective against most vegetative bacteria.