micro 13.1 pt 3

-cide

Refers to a treatment that kills the targeted microorganism.

-cidal

Indicates that a treatment kills microorganisms.

-stat

Refers to a treatment that stops microbial growth without necessarily killing the microorganisms.

-static

Indicates that a treatment inhibits microbial growth.

Bactericide

A substance or treatment that kills bacteria.

Viricide

A substance or treatment that kills or inactivates viruses.

Fungicide

A substance or treatment that kills fungi.

Bacteriostatic treatment

A treatment that inhibits the growth of bacteria without necessarily killing them.

Fungistatic treatment

A treatment that inhibits the growth of fungi.

Factors affecting -cidal or -static treatments

The type of microorganism, the concentration of the chemical, and the nature of the treatment.

Preference for bacteriostatic over bactericidal

It may be less toxic to humans and better preserves the integrity of treated material.

Use of -static chemicals in plastics

Incorporated into plastics to prevent microbial growth on the surface.

Examples of -static chemicals in products

Children's toys and cutting boards.

Effectiveness of bacteriostatic treatment for infections

It prevents the pathogen from multiplying, allowing the immune system to eliminate remaining microorganisms.

Microbial death curve

A graph used to show the progress and effectiveness of a microbial control treatment over time.

Population behavior during control protocol exposure

A fixed percentage of the population dies over each equivalent time interval.

Usefulness of percentage reduction

More useful than absolute numbers because microbial killing occurs at a constant percentage rate.

Scale used for microbial death curves

A semilogarithmic (semilog) scale.

Reason for plotting microbial death on semilog scale

Microbial death is generally logarithmic, making reduction easier to visualize.

Decimal reduction time (DRT)

The amount of time required for a treatment to produce a 1-log reduction in a microbial population.

Another name for decimal reduction time

The D-value.

Percentage of microorganisms killed during one D-value

90%.

Population change after one D-value

Decreases by one order of magnitude, leaving 10% of the original.

Remaining cells after one D-value from 10⁶

10⁵ cells.

Exposure time impact on microbial control

Longer exposure times generally kill more microorganisms.

Larger starting population treatment duration

Requires more time due to logarithmic microbial death.

Effect of disinfectant concentration on microbial control

Higher concentrations generally kill microorganisms more quickly and effectively.

Temperature effect on microbial control

Higher temperatures generally increase the rate of microbial killing.

Effect of bodily fluids and organic debris on disinfection

Limits contact between the antimicrobial agent and microorganisms, requiring longer or more intense treatment.

Major factors for selecting microbial control method

Exposure time, starting microbial population, microbial susceptibility, concentration or intensity of treatment, and conditions that interfere with contact.