Bactericidal vs Bacteriostatic: What's the Difference?

July 04, 2019
Bactericidal vs Bacteriostatic: What's the Difference?

Many of us are familiar with term "antibacterial" – the type of technologies that are widely used to treat fabrics, plastics and coatings to prevent bacteria.

They work by inhibiting the growth of and/or destroying unwanted microorganisms that are growing and replicating on surfaces or in fabrics.

These agents are well known for actively helping to keep surfaces cleaner, reducing odours and making product last longer; however, what is less commonly known is that products that help us control these microorganisms are divided into two general categories: bactericidal and bacteriostatic.

When you say each of the category titles out loud, they sound quite similar; however, there are specific defining features that help us to categorize different types of antimicrobials.

While we discuss what makes each category unique, it is important to keep in mind that at a certain level (or dosage) the “lines” may become blurred as to which of these categories the antibiotic truly belongs in.

For example, if the concentration of a bacteriostatic treatment is particularly high, it may perform in ways that are more reflective of the characteristics you would expect to see in a bactericidal, however, this does not mean the technology is inherently bactericidal.

Let’s look at the differences in meanings between bactericidal vs bacteriostatic.


The main defining feature of a bactericidal substance is that these antimicrobial treatments directly kill bacteria.

These agents “attack” microbes by affecting the cell wall, lipids, enzymes, or protein synthesis within the cell – sometimes even completing a combination of these mechanisms. By disrupting the cell wall structure of existing cells and inhibiting the formation of new cells, bactericidal substances cause bacterial cells to die off, therefore decreasing the amount found in the individual affected.

Bactericidal technologies contribute to irreversible cell death and are often chosen for materials that will be used in healthcare facilities where complete kill is targeted to maintain aseptic environments.


Bacteriostatic treatments differ from bactericidal versions in that they inhibit the growth and multiplications of bacterial cells, rather than directly kill them.

Bacteriostatic agents can achieve this by obstructing the metabolic mechanisms of the bacterial cell, in most cases targeting the protein synthesis. While doing this does not cause outright cell death, it does effectively inhibit further growth and DNA replication of the bacterial cells.

When bacteriostatic agents are utilized, the treatment will regulate the number of bacterial cells. While the bacteria will not be eliminated, their numbers will not increase.

Essentially, bacteriostatic treatments effectively keep bacterial cells from replicating.

Bacteriostatic substances produce reversible results. As mentioned in the introduction, very high treatment levels of bacteriostatic agents may eventually result in bactericidal characteristics – irreversible action and/or cell death.


Bactericidal products eliminate bacteria while bacteriostatic products keep bacterial populations in check by inhibiting replication.

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