ISO 16266-2-2018 PDF

Full title and description

ISO 16266-2:2018 — Water quality — Detection and enumeration of Pseudomonas aeruginosa — Part 2: Most probable number method. This International Standard specifies a rapid most probable number (MPN) enumeration method for Pseudomonas aeruginosa in a range of water types using an enzyme‑based reagent that produces a fluorescent signal from target organisms, enabling confirmed results within 24 hours.

Abstract

ISO 16266-2:2018 defines a liquid‑culture MPN procedure for the detection and enumeration of Pseudomonas aeruginosa in water. The method relies on growth of target cells in a nutrient reagent that contains a 7‑amino‑4‑methylcoumarin aminopeptidase substrate; hydrolysis by P. aeruginosa releases a fluorescent product detected under UV, and positive/negative well patterns are used to calculate MPN values from standard tables. The procedure is validated for many potable and recreational waters and is intended to provide a confirmed result within 24 hours without additional confirmation steps for positive wells when used as specified.

General information

• Status: Published (confirmed at review)
• Publication date: 19 July 2018
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 13.060.70 (Examination of biological properties of water / Microbiology of water)
• Edition / version: Edition 1 (2018)
• Number of pages: 122

Scope

This document specifies a method for the enumeration of Pseudomonas aeruginosa in water based on a most probable number (MPN) liquid‑culture technique using an enzyme‑substrate reagent. It is applicable to a range of waters including drinking water, non‑carbonated bottled water intended for human consumption, hospital water, groundwater, and swimming pool and spa pool waters — including samples with high heterotrophic background counts. The method has not been validated for carbonated bottled waters, flavoured bottled waters, cooling tower waters or marine waters; these matrices are outside the scope unless a laboratory performs appropriate validation before use.

Key topics and requirements

• Principle: growth in liquid reagent containing a 7‑amino‑4‑methylcoumarin aminopeptidase substrate that releases a fluorescent signal when hydrolysed by P. aeruginosa.
• Enumeration format: most probable number (MPN) calculation from positive/negative well patterns and MPN tables.
• Sample volumes and design: procedures for 100 ml and 250 ml sample sizes and multiple‑well dilution schemes to cover expected concentration ranges.
• Incubation and detection: defined incubation conditions and fluorescence inspection enabling confirmed positives within ~24 hours.
• Performance characteristics: method validation statements, limits of detection, and guidance for use with samples with high background flora.
• Exclusions and validation: explicit exclusions (carbonated, flavoured, cooling tower, marine waters) unless independently validated by the laboratory.
• Quality and interpretation: criteria for run acceptance, controls, reporting MPN results with confidence intervals, and recommendations for troubleshooting.

Typical use and users

Used by public‑health and environmental microbiology laboratories, water utilities, hospital and healthcare facility water management teams, bottled‑water producers, swimming pool and spa operators, regulatory authorities and third‑party testing laboratories. The method is intended for routine monitoring, outbreak investigation, compliance testing and quality control where timely detection of P. aeruginosa is required.

Related standards

ISO 16266-2:2018 is part of the ISO 16266 family addressing detection and enumeration of Pseudomonas aeruginosa. The earlier ISO 16266:2006 specifies a membrane‑filtration method for P. aeruginosa. National and regional adoptions (EN/ national variants) of ISO 16266-2 exist for harmonized use. Laboratories selecting a method should consider both the membrane filtration method and the MPN method for their specific matrices and regulatory requirements.

Keywords

Pseudomonas aeruginosa; water quality; MPN method; most probable number; enzyme substrate; fluorescent detection; Pseudalert; microbiology of water; rapid enumeration; potable water; recreational water; hospital water.

FAQ

Q: What is this standard?

A: ISO 16266-2:2018 is an International Standard that specifies a most probable number (MPN) liquid‑culture method for the detection and enumeration of Pseudomonas aeruginosa in various water types using an enzyme‑based fluorescent reagent.

Q: What does it cover?

A: It covers the principle, reagents, sample handling, dilution/well plating schemes, incubation and detection conditions, MPN calculation, quality controls and reporting for P. aeruginosa enumeration. It also lists water types for which the method is validated and those excluded unless validated by the laboratory.

Q: Who typically uses it?

A: Environmental and public‑health laboratories, water utilities, bottled‑water producers, hospital infection control teams, pool and spa testing labs, and regulatory bodies use this standard for routine monitoring and rapid detection of P. aeruginosa.

Q: Is it current or superseded?

A: ISO 16266-2:2018 was published in July 2018 (Edition 1). It has been subject to ISO periodic review; users should verify the current status with their national standards body or ISO catalogue to confirm there have been no subsequent revisions or amendments since publication.

Q: Is it part of a series?

A: Yes. It complements existing ISO work on Pseudomonas aeruginosa detection (for example the earlier ISO 16266 membrane filtration method) and has been adopted in various regional/national standards frameworks as part of the broader suite of water microbiology standards.

Q: What are the key keywords?

A: Pseudomonas aeruginosa, water quality, most probable number (MPN), enzyme substrate, fluorescent detection, rapid enumeration, microbiology of water.