prEN 17854

Antimicrobial wound dressings - Requirements and test method

This document specifies minimum requirements and a test method for the antimicrobial (microbicidal or microbistatic) activity of wound dressing products. It applies to all wound dressing products that specifically claim antimicrobial activity according to this document.

Antimikrobielle Wundauflagen - Anforderungen und Prüfverfahren

Dieses Dokument legt Mindestanforderungen und ein Prüfverfahren für die antimikrobielle (mikrobizide oder mikrobiostatische) Wirkung von Wundauflagen fest. Es gilt für alle Wundauflagen, die ausdrücklich eine antimikrobielle Wirkung nach diesem Dokument für sich beanspruchen.

Pansements antimicrobiens - Exigences et méthode d’essai

Le présent document spécifie les exigences minimales et une méthode d’essai pour l’activité antimicrobienne (microbicide ou microbiostatique) des produits de pansement. Il s’applique à tous les produits de pansement qui revendiquent spécifiquement une activité antimicrobienne conformément au présent document.

Antimikrobni sanitetni material - Zahteve in preskusne metode TC: Protimikrobni sanitetni material: - Zahteve in preskusne metode

General Information

• Status: Not Published
• Publication Date: 21-Mar-2024
• ICS: 11.120.20 - Wound dressings and compresses
• Technical Committee: CEN/TC 205 - Non-active medical devices
• Drafting Committee: CEN/TC 205/WG 15 - Antimicrobial wound care dressings
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 23-Mar-2023
• Due Date: 24-Mar-2023
• Completion Date: 23-Mar-2023
• Directive: 2017/745 - Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, amending Directive 2001/83/EC, Regulation (EC) No 178/2002 and Regulation (EC) No 1223/2009 and repealing Council Directives 90/385/EEC and 93/42/EEC
• Directive: 93/42/EEC - Council Directive 93/42/EEC of 14 June 1993 concerning medical devices
• Mandate: M/295 - Standardization mandate to CEN/CENELEC concerning the development of European standards relating to medical devices
• Ref Project: oSIST prEN 17854:2022 - Antimicrobial wound dressings - Requirements and test method

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN 17854:2022
01-september-2022
Antimikrobni sanitetni material - Zahteve in preskusne metode
Antimicrobial wound dressings - Requirements and test method
Antimikrobielle Wundauflagen - Anforderungen und Prüfverfahren
Pansements antimicrobiens - Exigences et méthode d’essai
Ta slovenski standard je istoveten z: prEN 17854
ICS:
11.120.20 Sanitetni materiali, obveze in Wound dressings and
komprese compresses
oSIST prEN 17854:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 17854:2022
DRAFT
EUROPEAN STANDARD
prEN 17854
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2022
ICS 11.120.20
English Version
Antimicrobial wound dressings - Requirements and test
method

Pansements antimicrobiens - Exigences et méthode Antimikrobielle Wundauflagen - Anforderungen und

d'essai Prüfverfahren

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 205.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations

which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17854:2022 E

worldwide for CEN national Members.
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Contents Page

European foreword ....................................................................................................................................................... 4

Introduction .................................................................................................................................................................... 5

1 Scope .................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 6

3 Terms, definitions, symbols and abbreviated terms .......................................................................... 6

3.1 Terms and definitions ................................................................................................................................... 6

3.2 Symbols and abbreviated terms ................................................................................................................ 8

4 Requirements ................................................................................................................................................... 9

4.1 Documentation and training ....................................................................................................................... 9

4.2 Microbicidal dressings ............................................................................................................................... 10

4.3 Microbistatic dressings .............................................................................................................................. 10

4.4 Performance table ....................................................................................................................................... 10

5 Test method ................................................................................................................................................... 10

5.1 Principle .......................................................................................................................................................... 10

5.2 General conditions ....................................................................................................................................... 11

5.2.1 Volume accuracy .......................................................................................................................................... 11

5.2.2 Agar plates ...................................................................................................................................................... 11

5.3 Materials and reagents ............................................................................................................................... 11

5.3.1 Test organism strains ................................................................................................................................. 11

5.3.2 Reagents and culture media ..................................................................................................................... 12

5.3.3 Test apparatus............................................................................................................................................... 14

5.4 Preparation of test and negative control dressings ........................................................................ 14

5.5 Calculation of saturation volume and working volume ................................................................. 15

5.6 Preparation of test organism suspensions ......................................................................................... 17

5.6.1 Bacteria ............................................................................................................................................................ 17

5.6.2 Yeast .................................................................................................................................................................. 18

5.6.3 Preparation of STOCK A .............................................................................................................................. 18

5.7 Neutralization validation .......................................................................................................................... 19

5.7.1 Preparation of inoculum ........................................................................................................................... 19

5.7.2 Neutralizer toxicity ...................................................................................................................................... 19

5.7.3 Test organism viability .............................................................................................................................. 20

5.7.4 Neutralizer efficacy ..................................................................................................................................... 20

5.7.5 Interpretation of data ................................................................................................................................. 21

5.8 Procedure........................................................................................................................................................ 23

5.8.1 Exposing the test and negative control dressings to test organisms ......................................... 23

5.8.2 Recovery and enumeration of test organisms ................................................................................... 24

5.8.3 Calculation and expression of results ................................................................................................... 25

5.8.4 Calculation of the detection limit of the test ...................................................................................... 28

5.8.5 Judgement of test validity ......................................................................................................................... 29

5.9 Test report ...................................................................................................................................................... 29

Annex A (informative) Referenced test organism strains in other national collections ................. 31

Annex B (informative) Validation of neutralization ..................................................................................... 32

Annex C (informative) Neutralizers.................................................................................................................... 33

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Annex D (informative) Rationale ......................................................................................................................... 34

Annex E (informative) Replicates ........................................................................................................................ 38

Annex F (informative) Test method illustrations .......................................................................................... 39

Annex G (informative) Example Test Report Tables..................................................................................... 44

Bibliography ................................................................................................................................................................. 46

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European foreword

This document (prEN 17854:2022) has been prepared by Technical Committee CEN/TC 205 “Non-

active medical devices”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
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Introduction

This document describes a test method for establishing whether a wound dressing exerts antimicrobial

activity.

The laboratory test attempts to simulate conditions of application, through the use of appropriate test

fluids, temperature, organisms, and contact times reflecting the parameters found in clinical situations.

Conditions which may influence the action of wound dressings having antimicrobial properties have

been included.

The conditions are intended to cover general purposes and to allow comparison between laboratories

and product types.

This edition of the document is considered to be most suited for dressings that have been tested as part

of the inter-laboratory comparisons, i.e. that have an active antimicrobial agent incorporated and with

at least a small amount of absorbent capacity. No data has currently been generated on other types of

dressing (e.g. film, non-absorbing, multi-layered, adhesive, bacteria-binding dressing, etc.).

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1 Scope

This document specifies minimum requirements and a test method for the antimicrobial (microbicidal

or microbistatic) activity of wound dressing products. It applies to all wound dressing products that

specifically claim antimicrobial activity according to this document.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 12353, Chemical disinfectants and antiseptics - Preservation of test organisms used for the

determination of bactericidal (including Legionella), mycobactericidal, sporicidal, fungicidal and virucidal

(including bacteriophages) activity
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
antimicrobial dressing

wound dressing which can be shown to exert microbicidal or microbistatic properties

3.1.2
antimicrobial activity

capability of a wound dressing to either inhibit the growth or produce a reduction in the number of

viable cells of relevant test organisms under defined conditions, including viable bacterial cells and/or

viable vegetative yeast cells
3.1.3
CFU
colony forming unit(s)
3.1.4
microbicidal

capability of the dressing to produce at least a 3 log reduction in the number of viable cells from the

challenge organisms when tested under the conditions in Clause 5
3.1.5
microbistatic

capability of the dressing to at least prevent further growth of the initial inoculum when tested under

the conditions in Clause 5
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3.1.6
negative control dressing

wound dressing which is the same dressing as the dressing to be tested but without the antimicrobial

treatment

Note 1 to entry: If no similar non-medicated dressing is available, then a sterile gauze swab shall be used.

3.1.7
neutralizer
chemical formulation to stop the antimicrobial effect of antimicrobial agents
3.1.8
plate count method

method in which the number of viable microorganisms present after incubation is calculated by

counting the number of CFU
3.1.9
plate factor

factor used in CFU calculations which accounts for the volume of suspensions plated out onto agar

plates

Note 1 to entry: This factor differs depending on choice of pour plates or spread plates.

3.1.10
saturation volume

maximum volume of fluid absorbed by the dressing when tested according to the method in 5.5 of this

document
3.1.11
simulated wound fluid
SWF

test medium intended to simulate wound exudate, for suspension of test organisms prior to exposure to

test sample
3.1.12
test dressing
wound dressing which is tested to assess its antimicrobial activity
3.1.13
working volume

volume of SWF added to the test or control dressing during the test, determined as 80 % of the

saturation volume (ml)
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3.2 Symbols and abbreviated terms

For the purposes of this document, the following symbols and abbreviated terms apply.

A Antimicrobial activity
C CFU value at T = 0 h for negative control dressing
C CFU value at T = 24 h for negative control dressing
C Microbial concentration of INOC C
Microbial concentration per sample (CFU / sample) used to calculate INOC C (in
Table 5)
C Viable counts per dressing sample
C Viable counts per ml
DF Dilution factor
h Hour
INITIAL STOCK Microbial suspension in MRD harvested from agar sub-culture
Inoculum for negative control dressing (prepared from STOCK B and calculated
INOC C
volume of uninoculated SWF equating to WV − 0,5 ml)
Inoculum for test dressing (prepared from STOCK B and calculated volume of
INOC T
uninoculated SWF equating to WV − 0,5 ml)
LOD Limit of detection
Log C is the average Log value for the number of organisms obtained from three
negative control dressing samples immediately after inoculation

Log T is the average Log value for the number of organisms obtained from three test

dressing samples after incubation for 24 h
min Minutes
N Average number of CFU on P and P
1 2
N Undiluted test suspension
NE Neutralization effectiveness (%)
N Average Neutralizer efficacy in neutralization validation (CFU/ml)
EFF
NT Neutralization toxicity (%)
N Average Neutralizer toxicity in neutralization validation (CFU/ml)
TOX
N Average Test organism viability in neutralization validation (CFU/ml)
VIAB
P The number of organisms on plate 1 of duplicate agar plates (CFU)
P The number of organisms on plate 2 of duplicate agar plates (CFU)
PF Plate factor
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s Second
Microbial suspension of INITIAL STOCK diluted in MRD to contain 3 × 10 CFU/ml
STOCK A
to 1 × 10 CFU/ml, used to prepare STOCK B and STOCK N
Microbial suspension of STOCK A diluted in SWF to contain 3 × 10 CFU/ml to
STOCK B
1 × 10 CFU/ml
Microbial suspension of STOCK A diluted in MRD to contain 1,5 × 10 CFU/ml to
STOCK N
5,0 × 10 CFU/ml, used in Neutralization Validation when using 1 ml pour plates
SV Saturation volume
SVA Average saturation volume of five replicates (g)
SV Highest percentage saturation volume of five replicates (%)
HIGH
SV Lowest percentage saturation volume of five replicates (%)
LOW
SV Highest measured saturation volume of five replicates (g)
MAX
SV Lowest measured saturation volume of five replicates (g)
MIN
SV Percentage spread for the five replicates (%)
SPREAD
T CFU value at T = 24 h for test dressing
V Neutralizer Volume
Volume sampled from the paddle blender bag when preparing serial decimal
dilutions in 5.8.2.4 (ml)
VT Test volume = Neutralizer volume (VN) + Working Volume (WVT or WVc) (ml)
W Average dressing weight at T = 0 h (g)
The average fully saturated dressing weight (g), as determined by the weight not
changing between two time points by more than 5 %

W Dressing weight following saturation in SWF at each time point as applicable (g)

Working volume (3.1.13) – the volume of SWF added to the test or control
dressing during the test, determined as 80 % of the saturation volume (ml)
WV Working volume (WV) added to the negative control dressing (ml)
WV Working volume (WV) added to the test dressing (ml)
4 Requirements
4.1 Documentation and training

Laboratories performing the test in this document should be operating under an appropriate quality

management system (such as EN ISO 13485 [1], EN ISO/IEC 17025 [2] or similar). Therefore, ensuring

that suitable records are retained by the test laboratory to allow full traceability of all raw data

contributing to the results in the test report (5.9) and that competence in microbiological testing has

been established.
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4.2 Microbicidal dressings

When tested using the test method described in this document, antimicrobial dressings shall

demonstrate an antimicrobial activity of at least a 3 log reduction in activity in a valid test (5.8.5) at the

mandatory contact time of 24 h (T = 24 h) and against all three test organisms (5.3.1).

NOTE 1 Log values in this document refer to Log .
NOTE 2 Rationale for microbicidal requirements is given in Annex D.
4.3 Microbistatic dressings

When tested using the test method described in this document, microbistatic dressings shall

demonstrate an antimicrobial activity that prevents further growth of the initial inoculum in a valid test

(5.8.5) at the mandatory contact time of 24 h (T = 24 h) and against all three test organisms (5.3.1). This

means at least a 0 log reduction is obtained, which represents no increase in test organism numbers at

the mandatory contact time of 24 h (T = 24 h) against all three test organisms (5.3.1).

4.4 Performance table

Table 1 shows the performance requirements for antimicrobial dressings to be classified as

microbicidal or microbistatic.
Table 1 — Performance requirements for antimicrobial dressings
Microbicidal Microbistatic
A ≥ 3,0 against all 3 test organisms A ≥ 0,0 against all 3 test organisms
A = Antimicrobial activity (5.8.3.5)

If a test dressing does not meet either a microbicidal or microbistatic requirement then it is non-

antimicrobial according to this document.

The test report (5.9) shall be supplied where claims of compliance with this document are made.

If a manufacturer makes a claim for antimicrobial activity for contact times in addition to the

mandatory contact time of 24 h (T = 24 h) then those additional time points may be tested using this

document and the results shall be included in the test report (5.9) and made available on request.

The test method in this document may be used with additional test organisms, including molds,

provided that appropriate neutralization validation has been performed. If the results using such

additional test organisms are made publicly available, then the neutralization validation shall be made

available on request.
NOTE Example tables are given in Annex G.
5 Test method
5.1 Principle

A test suspension of bacteria or yeast in a solution of simulated wound fluid is inoculated into a sample

of a wound dressing (test sample). The volume of test suspension added is determined by calculating

the saturation volume of the test sample prior to inoculation. The test sample is maintained at a

specified temperature for a defined contact time, then transferred to a previously validated

neutralization medium so that the action of the antimicrobial agent is neutralized. The number of

surviving bacteria or yeast, which can be recovered from the test sample, is then quantitatively

determined, and compared to the number of bacteria or yeast in a negative control at start of the test.

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The negative control sample dressing shall be treated in the same manner in place of the test sample

during the whole test period.
NOTE Rationale for chosen test parameters is given in Annex D.

Any permitted deviations to this test method shall be suitably validated, documented in the report and

their use justified.
5.2 General conditions
5.2.1 Volume accuracy

Volumes shall be measured with calibrated pipettes. Unless otherwise specified, all volumes are

expected to be accurate to ±5 %.
5.2.2 Agar plates

This document is written with the intention that 1 ml agar pour plates are used for enumeration.

However, it is known that some laboratories may be limited to the use of spread plates for enumeration.

The change in volume when spread plates are used requires accounting for at various points in the

method. Therefore, throughout this document instructions for the adjustments required when using

spread plates have been given and users of this document should ensure the required adjustments are

carefully followed.

NOTE The use of a very low volume for spread plates will reduce the sensitivity of the test and this may affect

the ability to ability to calculate the required 3 log reduction. Therefore, the use of 1 ml pour plates at all times is

encouraged.
5.3 Materials and reagents
5.3.1 Test organism strains
5.3.1.1 Storage of organisms

The organisms shall be stored in accordance with the supplier’s recommendations or EN 12353.

The identification and origin (culture collection) of the organisms as well as the laboratory storage

method shall be recorded.

National collection test organism strains equivalent to those listed in 5.3.1.2 and 5.3.1.3 may be used;

some common alternative references in other national collections are given in Annex A.

5.3.1.2 Bacteria
The following two strains of bacteria shall be evaluated:
Pseudomonas aeruginosa ATCC 9027
Staphylococcus aureus ATCC 6538
5.3.1.3 Yeast
The following strain of yeast shall be evaluated:
Candida albicans ATCC 10231
5.3.1.4 Additional test organism strains

Additional test organism strains to those listed in 5.3.1.2 and 5.3.1.3 may be used for evaluation. Their

suitability for producing inocula of sufficient concentration shall be verified prior to use.

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If the additional strains are not classified in a reference collection (e.g. clinical isolates), their

identification characteristics should be stated in the report and they should be held by the testing

laboratory for a minimum of five years to allow repeat testing if necessary.
5.3.2 Reagents and culture media
5.3.2.1 General

Reagents used in tests shall be of analytical quality and/or suited for microbiological purposes.

Dehydrated or ready-prepared products available on the commercial market are recommended for use

in preparing the culture media. The manufacturer’s instructions for the preparation, sterilization and

storage of culture media shall be strictly followed. Unless otherwise specified, all reagents shall be

equilibrated at ambient temperature (15 °C to 25 °C) before use.

Alternative media to those listed may be used, provided they have been suitably validated for use. The

TM TM1

use of alternative agar technologies, e.g. Petrifilm or Compact Dry plates, is also acceptable,

provided their use has been suitably validated and used to perform Neutralization Validation (5.7). Any

alternative media or media technologies shall be documented in the report as a deviation (5.9).

Substitution of FCS in the SWF (5.3.2.5) is not recommended (see Annex D, D.8).
5.3.2.2 Water

Purified water shall be used for the preparation of culture media, i.e. distilled, demineralized, deionized

or produced by reverse osmosis, or of equivalent quality free from substances likely to inhibit or

influence the growth of the microorganisms under the test conditions, e.g. traces of chlorine, traces of

ammonia and traces of metal ions.
NOTE See EN ISO 11133 [3] for more information on culture media preparation.
5.3.2.3 Tryptone Soya Broth (TSB)
For the maintenance of bacteria and performance of viable counts.
Tryptone, pancreatic digest of casein 15,0 g
Soya peptone, papaic digest of soya 5,0 g
NaCl 5,0 g
Water to 1 000 ml

Sterilize in the autoclave. After sterilization, the pH shall be between 7,1 to 7,5.

5.3.2.4 Tryptone Soya Agar (TSA)
For the maintenance of bacteria and performance of viable counts.
Tryptone, pancreatic digest of casein 15,0 g
Soya peptone, papaic digest of soya 5,0 g
NaCl 5,0 g
Agar 15,0 g
Water to 1 000 ml
1 TM TM

Petrifilm and Compact Dry are examples of alternative agar products available commercially. This

information is given for the convenience of the users of this document and does not constitute an

endorsement by CEN or CENELEC of these products.
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Sterilize in the autoclave. After sterilization, the pH shall be between 7,1 to 7,5.

5.3.2.5 Simulated Wound Fluid (SWF)
For suspension of test organisms prior to exposure to test sample.
Maximum Recovery Diluent (5.3.2.6) 50 %
Fetal Calf Serum (sterile, heat inactivated*) 50 %
Mix MRD and fetal calf serum under aseptic conditions.
NOTE *Complement inactivated by the supplier or by the laboratory prior to use.
5.3.2.6 Maximum recovery diluent (MRD)
For preparation of SWF and test organism suspensions.
Peptone 1,0 g
NaCl 8,5 g
Water to 1 000 ml

Sterilize in the autoclave. After sterilization, the pH shall be between 6,8 to 7,2.

5.3.2.7 Sabouraud broth (SAB)
For the maintenance of yeast and performance of viable counts.
Peptone Neutral Bact. Peptone 10 g
Distilled water 1 000 ml
Heat to boiling to dissolve the peptone completely. Then add:
Glucose puriss (dextrose) 20 g

Dissolve the glucose by hand as soon as possible in the hot, but not boiling agar, and mix.

Sterilize in the autoclave. After sterilization, the pH shall be between 5,8 to 6,0.

5.3.2.8 Sabouraud agar (SAA)
For the maintenance of yeast and performance of viable counts.
Peptone Neutral Bact. Peptone 10 g
Agar bacteriological 18 g
Distilled water 1 000 ml
Heat to boiling to dissolve the peptone completely. Then add:
Glucose puriss (dextrose) 20 g

Dissolve the glucose by hand as soon as possible in the hot, but not boiling agar, and mix.

Sterilize in the autoclave. After sterilization, the pH shall be between 5,8 to 6,0.

5.3.2.9 Neutralizer

The neutralizing solution shall be validated for the active substance in the product under test in

accordance with 5.7. The neutralizer shall be sterile prior to use.
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NOTE Information on neutralizers that have been found to be suitable for some categories of products is

given in Annex C.
5.3.3 Test apparatus

Usual microbiological laboratory apparatus shall be required and in particular the following:

5.3.3.1 Spectrophotometer, capable of measuring at a 600 nm to 660 nm wavelength, or

McFarland’s nephelometer.
5.3.3.2 Incubators, capable of
...