Disinfectant Tests for Medical Areas
The main goal of disinfection in medical areas is to prevent an infection and maintain sterility of the environment. In order to measure the performance of chemical disinfectants, the general requirements are defined by standards like EN 14563 and EN 14348. Both standards focus on the same feature of a disinfectant, which is its activity against mycobacteria. However, the standard methods are different. This paper discusses in detail the comparison of EN 14563 and EN 14348, including their similarities and differences and their efficacy.
EN 14563
Scope and application
EN 14563 is phase 2, step 2 carrier test for the assessment of mycobactericidal or tuberculocidal activity of chemical disinfectants used in the medical area. The standard is intended to verify the efficacy of disinfectants under conditions that mimic real life situations.
Test Methodology
The EN 14563 test involves applying a test suspension of mycobacteria onto a glass carrier, which is then exposed to the disinfectant. The carrier is immersed in the disinfectant solution and maintained at a specified temperature for a set contact time. After exposure, the carrier is transferred to a neutralizer to halt the disinfectant’s action, and the surviving mycobacteria are counted to determine the disinfectant’s efficacy.
Key Features
- Test Organisms: The standard requires testing against Mycobacterium avium and Mycobacterium terrae. The Mycobacterium avium is used for mycobactericidal activity and Mycobacterium terrae is used for tuberculocidal activity.
- Conditions: The evaluations are done under clean (0.3 g/L bovine albumin) and dirty (3 g/L bovine albumin + 3 ml/L sheep erythrocytes) conditions.
- Temperature and Contact Time: Test conditions include the temperature of 20°C and contact time of 60 minutes, with other test conditions being optional and being based on practical use.
- Neutralization: A strictly validated neutralizer is used to stop the action of the disinfectant and this is needed for control and result accuracy.
EN 14348
Scope and application
EN 14348 outlines a quantitative suspension test for evaluating the mycobactericidal activity of chemical disinfectants, including those used on medical instruments. This phase 2, step 1 test focuses on the disinfectant’s efficacy in suspension, which is a preliminary assessment compared to the more application-oriented carrier test of EN 14563.
Test methodology
In EN 14348, the disinfectant is seeded with the suspension of mycobacteria and maintained at a defined temperature for a defined contact time. After exposure, an aliquot is taken and the action of the disinfectant is neutralized. Then, surviving mycobacteria are enumerated, giving the effectiveness of the disinfectant.
Key features
- Test Organisms – Similar to EN 14563, it uses Mycobacterium avium and Mycobacterium terrae for mycobactericidal activity.
- Conditions – Tests are performed under clean (0.3 g/L bovine albumin) and dirty (3 g/L bovine albumin + 3 ml/L sheep erythrocytes) conditions.
- Temperature and Contact Time: Test conditions are obligatory 20°C for 60 minutes, with other test conditions being optional and being based on practical use.
- Neutralization: A strictly validated neutralizer is used to stop the action of the disinfectant, and this is needed for control and result accuracy.
Similarities between EN 14563 and EN 14348
Mandatory test organisms
Both standards use Mycobacterium avium and Mycobacterium terrae as test organisms, focusing on their mycobactericidal activity. This similarity ensures that the disinfectants are tested against relevant and tough microorganisms.
Area of application
Both standards EN 14563 and EN 14348 are applicable to a number of different places, including:
Hospitals: Useful to assess general hospital disinfection including surfaces and equipment.
Community medical facilities: Relevant to disinfectants used in clinics, dental offices, and other outpatient facilities.
Nursing homes: To assure adequate disinfection in long-term care facilities, aimed to act on mycobacteria.
Workplace and home: Although primarily medical, it also includes settings in places where disinfection is crucial, workplaces and homes, particularly where vulnerable populations are housed.
Kitchens and laundries: Relevant to services which provide products directly for patient use to assure that these locations are not contaminated.
Test conditions
The two standards require using both dirty and clean conditions, representing different practical situations in which the disinfectants may be in use. The use of bovine albumin and sheep erythrocytes in dirty conditions acts by creating organic load, a condition that may affect the performance of the disinfectants.
Temperature and contact time
The point of comparison is that the test conditions for both of the standards are 20°C over 60 min. Additional conditions can also be accommodated by the two test standards to better fit the other use conditions.
Neutralization
For both EN 14563 and EN 14348, a validated neutralizer should be used so that the action of the disinfectant is inactivated. It is an essential method to make sure that the mycobacterial count accurately describes the efficacy of the disinfectant and that disinfection is not occurring during counting.
Differences between EN 14563 and EN 14348
Test methodology
- EN 14563: A quantitative carrier test is done where mycobacteria are dried on a glass carrier. This is crucial as it creates a simulation of the different fluids that may land on the medical instruments before the disinfection process. As such, the method represents the condition experienced practically, giving an adequate representation of the practical level of efficacy of disinfection.
- EN 14348: A quantitative suspension test, although it might be thought of as the first step of an investigation. It may offer preliminary information regarding the activity of the disinfectants as the mycobacteria are suspended in the disinfecting solution, a more generic measure of the disinfectant before application-specific tests are done.
EN 14563 and EN 14348 play an important role in testing the efficacy of chemical disinfectants, mainly in medical areas. To achieve that, while EN 14563 provides a more practical and application-oriented approach for testing the disinfectants, EN 14348 gives a preliminary assessment on the mycobactericidal activity. Knowledge about the similarities and differences of the respective standards helps in selecting the test methods for specific disinfectants used in medical areas. Both of these standards taken together ensure a comprehensive assessment of disinfectants for a more secure and better modality of disinfection practice within medical setups.
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