Biofilm Basics: Resistance and Removal

In our previous post, Biofilm Basics: How it’s formed, we learned about how biofilm is formed and its Extracellular Polymeric Substance (EPS). What makes biofilm so dangerous to public health is its outstanding resistance to antibacterial treatments and disinfection.

Resistance to antimicrobial treatment

Resistance is the ability not to be affected by something, especially adversely. Simply stated, biofilm provides a protective home that helps pathogens resist disinfection. In fact, research has shown that bacteria in biofilm are often up to 1,000 times more tolerant to antimicrobial treatment than their planktonic (free-floating) counterparts due to different mechanisms. The EPS acts as the first line of defense against factors such as lack of water, high or low pH, or the presence of antibiotics or antimicrobials.

The multicellular construction of biofilms provides protection for cells. Understanding biofilm tolerance and its susceptibility to antimicrobials is dependent on multiple factors such as the number of different microbial species within a biofilm, antimicrobial density and type, cell density or thickness, and the age of the biofilm. Biofilm cell density and biofilm age are often strongly correlated.

Biofilm protects pathogens from disinfection and allows organisms injured by environmental stress and disinfectants to recover and grow. This leads to improved resistance to antimicrobials and antibiotics over time as ‘stronger’ organisms continue to survive. Biofilms are dynamic and responsive to their environment, and bacterial cells may detach from biofilms individually or in clumps. When they detach in clumps, they retain the reduced susceptibility to antimicrobials characteristic of biofilms.

Removing biofilm

The best way to protect against biofilm is to prevent its formation. Oxidizing chemistries, such as chlorine bleach and PAA, will kill free-swimming and surface-level biofilm-related microorganisms. The issue is they leave the EPS structure intact, especially the inner layers. It is not sufficient to simply kill surface organisms, and it can require up to 1,000 times the normal dose of a commercial sanitizer to completely remove a biofilm. This strong of a dose would be off-label and introduces additional issues, such as corrosivity concerns. It is imperative to completely remove biofilm to avoid continued resistance. Bacteria can repopulate in an intact EPS structure within 48 hours. However, if the structure is completely removed, it will take closer to one week (168 hours) for the biofilm colony to begin reforming. Additional exposure to antimicrobials can also delay the process of biofilm reformation.

Proprietary Technology

Sterilex’s patented PerQuat® technology was the first chemistry to receive EPA-registered anti-biofilm claims for industrial and public health use sites. It has the unique ability to collapse the protective matrix, penetrate the biofilm, kill pathogenic microorganisms, dissolve the biofilm structure, and chemically scrub the structure from a surface*. Dissolving the biofilm structure and fully removing it from a surface is a proactive approach in preventing the repopulation of biofilm matrix and microbial contamination.

At a high level, the active ingredients in Sterilex Ultra Disinfectant Cleaner Solution 1 and Sterilex Ultra Activator Solution are based on quaternary ammonium compounds (commonly referred to as quat) and Hydrogen Peroxide. Both compounds are listed on our label. In reality, using both ingredients offers more benefits and synergy than either chemistry alone. In our system, the primary role of quat is to serve as a phase transfer agent, combining with the peroxide ion to form a “PerQuat” molecule. This combination gives Sterilex liquids their unique biofilm efficacy properties and provides a powerful level of performance through multiple physical and chemical mechanisms of action, including hydrolysis and oxidation.

Biofilm Key to Diagram
Biofilm polysaccharide matrix

PerQuat technology attacks and bombards biofilm

perquat penetrates the outer layer and dissolves into the matrix

Penetrates the outer layer and dissolves into the matrix

Destruction and elimination of biofilm by a unique combination of oxidation, hydrolysis, and solubilization

Destruction and elimination of biofilm by a unique combination of oxidation, hydrolysis, and solubilization

The Sterilex Advantage

Waterlines should be cleaned and sanitized between every flock or placement to not only prevent cross-contamination, but also to prevent the build-up of biofilm and scale, control dangerous pathogens, and improve overall water quality and drinkability. Clean, uncontaminated water directly impacts flock health and performance. Sterilex Ultra Disinfectant Cleaner Solution 1, when mixed with Sterilex Ultra Activator Solution, provides efficacy against biofilm* in waterlines and kills and inactivates organisms and viruses such as Salmonella, E. Coli, Campylobacter, Avian Influenza and other poultry and swine pathogens.


*Biofilm removal claim is not approved in California. Biofilm removal claim for non-public health uses only.

About Megan Macy

* The content provided on this webpage is provided for informational purposes only and does not supersede the product label requirements. Approved label claims may vary depending on geography, use site, organism, or other factors. Always refer to the product label for complete directions for use.
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