🦠 Coagulase-positive staphylococci in swimming pool water according to Annex A to PN-Z-11001-3 — a method from the standard on bottled waters

Microbiology PN-Z-11001-3

Overview

WHAT THIS STANDARD IS — AND WHY THIS IS SURPRISING. PN-Z-11001-3:2000 is entitled "Bottled natural mineral and medicinal waters — Quality requirements and testing of bottled medicinal waters". Its subject is bottled waters, not swimming pool water. In accreditation scopes, however, it stands next to the methodology "Liczba gronkowców koagulazo-dodatnich" [number of coagulase-positive staphylococci] and the matrix "Woda na pływalniach" [swimming pool water] — because laboratories cite its ANNEX A, which describes the method for determining these bacteria. Twenty-one of the twenty-nine citations indicate the annex explicitly ("Załącznik A", "zał. A", "(zał. A)", "Zał. A" [Annex A]).

STATUS (state of the PKN card on 23.09.2026). The standard is WITHDRAWN. Publication date 25-04-2000, WITHDRAWAL DATE 17-12-2019, number of pages 11, technical body RS SZŚ (Sector Council of the Health, Environment and Medicine Sector), ICS 67.160.20 (beverages). The card contains no "Replaced by" row.

WHAT LABORATORIES CITE (measurement on the database of scopes, reading of 23.09.2026): 29 entries at 24 laboratories across all forms of notation; 27 entries at 22 laboratories when matching by the BEGINNING of the notation — this is the number the "Laboratories" tab shows. Matrices: "Woda na pływalniach" [swimming pool water] (13 entries), "Woda, Woda do spożycia przez ludzi" [water, water intended for human consumption] (4), "Woda (w tym woda na pływalniach)" [water (including swimming pool water)] (2), "Woda" [water] (2). Technique: membrane filtration method — 26 entries.

THE METHODOLOGY HAS TWO NAMES. Twelve entries write "Liczba gronkowców koagulazo-dodatnich", nine "Liczba gronkowców koagulazododatnich" (without a hyphen) [both: number of coagulase-positive staphylococci], and two — "Liczba Staphylococcus aureus" [number of Staphylococcus aureus]. The third name is not equivalent to the first two: coagulase-positive staphylococci are a group to which Staphylococcus aureus belongs, but it is not its only member. We do not settle whether these two laboratories determine a narrower subject or merely named it differently — we note it because only the name is visible in the report.

THE REGULATION REQUIRES THIS TEST IN ONLY ONE CASE. The regulation of the Minister of Health on the requirements for swimming pool water (consolidated text — Journal of Laws 2022 item 1230) gives in Annex No. 1 the microbiological requirements in five columns: water fed into the pool from the circulation system, water in the pool basin, water in pools equipped with devices producing a water-air aerosol, WATER IN POOLS USED FOR SWIMMING LESSONS FOR INFANTS AND YOUNG CHILDREN UNDER 3 YEARS OF AGE, and water in showers. In the row "Gronkowce koagulazododatnie w 100 ml wody" [coagulase-positive staphylococci in 100 ml of water], four columns have a dash, and the value "0" stands ONLY in the column for pools for infants and children under 3. For other kinds of pool water the regulation does not require this test.

THE REGULATION INDICATES THE TECHNIQUE, BUT NOT THE STANDARD. In the list of method characteristics of the same regulation, next to the item "Gronkowce koagulazododatnie" [coagulase-positive staphylococci] there is a detection limit of 1/100 ml and the method: MEMBRANE FILTRATION. The regulation does not give the number of a Polish Standard for this parameter — and this explains why laboratories reached for the annex to the standard on bottled waters: it is an available description of the method for this group of bacteria, not a document dedicated to pool water.

ONE EXCLUSION SAYS MORE THAN THE REST OF THE NOTATION. Two laboratories cite the annex with clause A.5.2.1 excluded, and one adds: "z potwierdzeniem aminopeptydazy" [with aminopeptidase confirmation]. The excluded clause therefore concerns one of the tests confirming the identity of the grown colonies, and the laboratory indicates which test replaces it. WE DO NOT GIVE the content of clause A.5.2.1 — we did not have the text of the standard.

WHAT WE DO NOT GIVE. We did not have the text of the standard or of its Annex A. We DO NOT GIVE the type of medium, the volume of sample filtered, the incubation temperature and time, the way of confirming coagulase or the reading criteria. We know from the accreditation scopes that the technique is membrane filtration, and from the regulation — that the detection limit is to be 1 cfu in 100 ml.

Method principle

A measured volume of water is passed through a membrane filter that retains bacteria, the filter is transferred onto a medium and incubated, and the grown colonies are counted and confirmed as coagulase-positive staphylococci. The result is given as the number of colony-forming units in 100 ml. WE DO NOT DESCRIBE THE DETAILS — the medium, the incubation conditions, the confirmatory tests: we did not have the text of the standard or of its Annex A; we give the technique (membrane filtration) and the detection limit (1/100 ml) after the accreditation scopes and the regulation.

Applications

• Testing water in pools for swimming lessons for infants and children under 3 years of age — the only case in which the regulation requires this parameter
• Control tests of pool water carried out beyond the requirements of the regulation
• Reading an accreditation scope in which a standard on bottled waters stands next to pool water
• Checking whether the laboratory determines the whole group of coagulase-positive staphylococci or the species Staphylococcus aureus alone

Key parameters

Standard

Standard number

PN-Z-11001-3:2000, Załącznik A (wersja polska)

Title (PL)

Butelkowane naturalne wody mineralne i lecznicze — Wymagania jakościowe i badania dotyczące butelkowanych wód leczniczych

Step-by-step procedure

1. Establishing whether the test is required

   The regulation on swimming pool water requires coagulase-positive staphylococci (0 in 100 ml) only for water in pools for swimming lessons for infants and children under 3. For other kinds of pool water the test is voluntary — and then it must be agreed with the client what it is carried out for.

2. Checking which document stands in the laboratory's scope

   The method comes from Annex A to PN-Z-11001-3:2000 — the standard on bottled mineral and medicinal waters, withdrawn on 17-12-2019. A citation of the standard number alone, without indicating the annex, does not say where the description of the method was taken from.

3. Sampling and filtration

   Pass a measured volume of water through a membrane filter. The detection limit required by the regulation is 1 cfu in 100 ml, which determines the minimum volume of sample to be filtered.

4. Incubation

   Transfer the filter onto the medium and incubate. We do not give the type of medium, the temperature or the time — we did not have the text of the annex.

5. Reading and confirmation

   Count the grown colonies and confirm that they belong to the coagulase-positive staphylococci. If the accreditation scope excludes clause A.5.2.1 of the annex, the report is to state which test replaced the excluded confirmation.

6. Reporting the result

   Give the result as the number of colony-forming units in 100 ml of water and compare it with the requirement of 0 in 100 ml — remembering that this requirement concerns only pools for infants and children under 3.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The standard from which the method comes concerns bottled mineral and medicinal waters, not pool water — citing its number without indicating Annex A does not tell the reader where the description of the test was taken from
• The standard has been withdrawn since 17-12-2019 and has no successor on the card, and the regulation on swimming pool water does not indicate any Polish Standard for this parameter — the reference document must be described precisely in the report
• "Liczba Staphylococcus aureus" [number of Staphylococcus aureus] is not the same as "number of coagulase-positive staphylococci": the species is part of the group, so the result for the species may be lower than for the group with the same sample
• The requirement of a zero count of staphylococci concerns only pools for infants and children under 3 — a positive result for another pool is not an exceedance of the value in the regulation, although it is sometimes read as such
• Excluding clause A.5.2.1 changes the way colonies are confirmed — without recording this in the report the reader does not know with which test the result was confirmed

Frequently asked questions