Understanding Microorganisms & Infection Control

Why Understanding Microorganisms Matters
Every day, professional nail, beauty and podiatry services involve close contact with skin, nails, tools, equipment and surfaces.While many microorganisms are harmless, some have the potential to cause infections if transferred between clients through contaminated instruments, surfaces or equipment.This is why effective cleaning, disinfection and instrument processing are fundamental parts of professional practice.To understand why some disinfectants perform differently, it is important to first understand the microorganisms they are designed to control.
What Are Microorganisms?
Microorganisms are microscopic living organisms that cannot usually be seen with the naked eye.They exist naturally in the environment and can be found on:
  • Skin
  • Nails
  • Hair
  • Tools
  • Work surfaces
  • Dust
  • Water
  • Air
Not all microorganisms are harmful.In fact, many play an important role in maintaining healthy ecosystems and healthy skin.However, some microorganisms can cause infections when introduced into vulnerable areas of the body.The main groups relevant to infection control are:
  • Bacteria
  • Viruses
  • Yeast
  • Fungi
  • Mycobacteria
  • Bacterial spores
Bacteria
Bacteria are single-celled microorganisms capable of reproducing rapidly under suitable conditions.Many bacteria are completely harmless and some are beneficial.Others can cause infections if transferred to damaged skin, wounds or mucous membranes.Because bacteria reproduce quickly, even small numbers can multiply rapidly when conditions are favourable.Common bacteria evaluated during disinfectant testing include:
  • Staphylococcus aureus
  • MRSA
  • Pseudomonas aeruginosa
  • Escherichia coli (E. coli)
  • Enterococcus hirae
  • Klebsiella pneumoniae
  • Acinetobacter baumannii
What Is Staphylococcus Aureus?
Staphylococcus aureus is one of the most common bacteria found on human skin.In most cases it causes no problems.However, if it enters damaged skin or wounds it may cause infections ranging from minor skin irritation to more serious complications.Because it is commonly found on the skin, it is frequently used in disinfectant testing.
What Is MRSA?
MRSA stands for Methicillin-Resistant Staphylococcus Aureus.It is a strain of Staphylococcus aureus that has developed resistance to multiple antibiotics.MRSA became a significant concern within healthcare environments because infections are more difficult to treat once established.While disinfectants do not rely on antibiotics to work, MRSA remains an important challenge organism used during efficacy testing.
What Is Pseudomonas Aeruginosa?
Pseudomonas aeruginosa is a highly adaptable bacterium commonly found in water and moist environments.It is particularly known for its ability to survive in challenging conditions and form protective biofilms.Pseudomonas is often used during disinfectant testing because it can be more resistant to environmental stresses than many common bacteria.
What Is Escherichia Coli (E. coli)?
E. coli is a bacterium naturally present within the intestinal tract.While many strains are harmless, some have the potential to cause illness.E. coli is commonly used as a representative challenge organism during disinfectant testing.
Viruses
Viruses differ significantly from bacteria.Unlike bacteria, viruses cannot reproduce independently.Instead, they must enter a living host cell and use that cell to reproduce.Because of this, viruses behave differently and often require separate testing standards.Common viruses evaluated during disinfectant testing include:
  • Coronavirus surrogates
  • Adenovirus
  • Calicivirus
  • Parvovirus
Why Are Viruses Tested Separately?
A disinfectant that performs well against bacteria may not necessarily perform equally well against viruses.This is why dedicated virucidal standards such as EN 14476 exist.Different viruses also vary significantly in their resistance to disinfectants.For example, non-enveloped viruses such as parvovirus are generally more difficult to inactivate than enveloped viruses such as coronaviruses.
Yeast
Yeasts are microscopic fungi.While many yeasts exist naturally within the environment and on the body, some can cause infections when conditions allow excessive growth.The most common yeast used during disinfectant testing is:
  • Candida albicans
Because yeasts differ significantly from bacteria, separate testing standards are required to evaluate disinfectant efficacy.
Fungi
Fungi are a diverse group of organisms that include moulds and filamentous fungi.Some fungal species can survive in challenging environments and may be more difficult to eliminate than many bacteria.Common fungal challenge organisms include:
  • Aspergillus brasiliensis
Fungicidal testing helps demonstrate whether a disinfectant can effectively control these organisms.
What Is Candida?Candida is a genus of yeast naturally found on the skin and within the body.Under normal circumstances it is harmless.However, excessive growth can lead to fungal infections.The most commonly tested species is:
  • Candida albicans
This organism is frequently used in both yeasticidal and fungicidal efficacy testing.
What Is Candida Auris?
Candida auris has attracted significant attention in healthcare environments due to its persistence and ability to spread within clinical settings.Unlike many other yeasts, Candida auris can survive on surfaces for prolonged periods and may be more difficult to control.Because of this, it is increasingly included in disinfectant efficacy studies.
Mycobacteria
Mycobacteria are a specialised group of bacteria with unique cell walls that make them significantly more resistant to chemical disinfectants than many common bacteria.Common challenge organisms include:
  • Mycobacterium terrae
  • Mycobacterium avium
Because they are harder to eliminate, dedicated standards such as EN 14204 exist specifically to evaluate mycobactericidal efficacy.
What Are Bacterial Spores?
Bacterial spores are often considered the ultimate challenge in disinfectant testing.When certain bacteria encounter harsh environmental conditions, they can transform into an extremely resistant dormant state known as a spore.In this state they become significantly harder to destroy.Spores can survive:
  • Drying
  • Heat
  • Chemical exposure
  • Environmental stress
far better than most microorganisms.This is why sporicidal efficacy is often regarded as one of the most demanding forms of disinfectant testing.
What Is Clostridioides Difficile (C. difficile)?
Clostridioides difficile, often referred to as C. difficile or C. diff, is one of the most significant spore-forming bacteria encountered in healthcare environments.Its spores are highly resistant and can survive for extended periods on contaminated surfaces.Because of this, C. difficile spores are frequently used as challenge organisms during sporicidal testing.
What Are Bacillus Spores?
Bacillus species are another group of spore-forming bacteria commonly used during disinfectant testing.Examples include:
  • Bacillus subtilis
  • Bacillus cereus
These spores are specifically chosen because they provide a demanding challenge for disinfectants.
What Are Biofilms?
A biofilm is a protective community of microorganisms that attaches itself to a surface. Once established, biofilms become significantly more difficult to remove than individual microorganisms. Biofilms may develop on:
  • Instruments
  • Water systems
  • Work surfaces
  • Equipment
This is one reason why regular cleaning is just as important as disinfection. Cleaning helps remove the contamination that microorganisms need in order to establish and maintain biofilms.
Why Some Microorganisms Are Harder To Kill Than Others
Not all microorganisms have the same level of resistance. In general:
Easier To Eliminate
  • Many common bacteria
  • Many enveloped viruses
More Challenging
  • Yeasts
  • Fungi
  • Mycobacteria
Most Challenging
  • Bacterial spores
This is why different EN standards exist and why broad-spectrum efficacy testing is so important.
Why Spores Are The Ultimate Challenge
During disinfectant development, bacterial spores are often selected as challenge organisms for a simple reason: They are among the most resistant forms of microbial life. If a disinfectant can successfully demonstrate sporicidal efficacy against highly resistant spores such as:
  • Clostridioides difficile
  • Bacillus subtilis
  • Bacillus cereus
it provides strong evidence of broad antimicrobial performance.For this reason, sporicidal standards such as EN 13704 and BS EN 17126 are often regarded as some of the most demanding and valuable disinfectant tests available.
Infection Control Is More Than Disinfection
Effective infection control relies on multiple steps working together:
  1. Cleaning
  2. Disinfection
  3. Rinsing
  4. Drying
  5. Storage
  6. Sterilisation (where applicable)
No single product replaces good hygiene practices. Understanding the microorganisms we are trying to control helps professionals make informed decisions about cleaning, disinfection and instrument processing.Professional hygiene begins with understanding what cannot be seen.


Where Do KORRA HygienTabs™ Fit?

KORRA HygienTabs™ combine both a detergent system and a disinfectant system within the same solution.The detergent helps loosen and lift light contamination, oils and debris during processing, while the disinfectant works to reduce microorganisms present on the instrument.For routine professional use, this integrated approach can help simplify workflows and reduce the need for extensive pre-cleaning of lightly contaminated instruments.However, no disinfectant should be expected to penetrate heavy visible contamination, dried product build-up or large accumulations of debris.Where instruments contain obvious contamination, this should always be removed before disinfection.


 

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