Colikat Neu

Enumeration of Escherichia coli and coliform bacteria in 18 hours

COLIKAT RAPID is a fast test to simultaneously detect both total coliforms and Escherichia coli in water samples providing the test’s results within 18 hours. COLIKAT RAPID is suited for the entire water matrix.

The water samples to be tested are incubated overnight so that they are ready to read early the next day. Therefore COLIKAT RAPID delivers significant workflow benefits and speed in the event of a contamination issue. The test’s high sensitivity enables early coliform detection in water distribution systems, assisting to help to reduce biofilm buildup and sporadic downstream contamination events. As compared to the alternative conventional method using Chromogenic Coliform Agar (CCA; ISO 9308-1) for detection, COLIKAT RAPID significantly reduces false alarms created by inaccurate false positive results which give rise to uncertainty and unnecessary expense.

  • Simultaneous detection and quantification of Escherichia coli and total coliforms for the entire water matrix.
  • Sample evaluation after 18 hours.
  • Optimized workflow in your laboratory: The sample evaluation takes place after 18 hours before the reception of next days’ samples.
  • Enumeration of Escherichia coli and coliform bacteria in water samples acc. to EN ISO 9308-2.

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Test Principle

COLIKAT RAPID uses certain specific characteristics of both Escherichia coli and coliform bacteria for identification of the species. The test contains MUG and ONPG, two common nutritional indicators. Coliform bacteria use their enzyme β-Galactosidase to metabolize ONPG turning the sample yellow. Escherichia coli – other then most coliform bacteria – additionally has the enzyme β-Glucuronidase that enables it to hydrolyze MUG so that the sample additionally shows fluorescence under UV-light.

Most of non-coliform bacteria possess neither the β-Galactosidase nor the β-Glucuronidase. Therefore, they cannot transform MUG and ONPG and the test will not detect them. Yet, some non-coliform bacteria contain the enzymes. COLIKAT RAPID therefore uses selective supplements that inhibit the growth of those bacteria. The combination of the test’s enzymes and selective supplements prevents some common problems of conventional culture methods such as Chromogen Coliform Agar CCA (EN ISO 9308-1):

  • False positive results are prevented (for example for Aeromonas spec.)
  • The growth of non-target organism is prohibited. This way non-target organisms cannot affect (or even inhibit) the growth of Escherichia coli and coliform bacteria

Application – User Manual

Regulatory Environment and Compliance

COLIKAT RAPID is a fast test to simultaneously detect both total coliforms and Escherichia coli in water samples. The testing method has been described as ISO standard for detecting total coliforms and Escherichia coli in water (ISO 9308-2). In European Union (EU) Directive 2015/1787 EC requires the member states to – implement ISO 9308-2 into national legislation.

The requirements for the quality of water intended for human consumption within the European Union are bindingly set by EU regulation:

  • DIRECTIVE 98/83/EC – quality of water intended for human consumption
  • DIRECTIVE 2015/1787 EC amending Annexes II and III to Council Directive 98/83/EC on the quality of water intended for human consumption

A number of ISO standards have been established for analyzing microbiological parameters. EN ISO 9308-1 and EN ISO 9308-2 (for the enumeration of Escherichia coli and coliform bacteria) provide all necessary specifications for performing the analysis of Escherichia coli and coliform bacteria. The actual standards to be applied, reflecting the latest scientific and technical progress, are reflected by the amendments to Annex III of Directive 98/83/EC. The microbiological parameters and methods of analysis are specified in Annex III to Directive 98/83/EC that has been amended as follows by Directive  2015/1787 EC:

“The methods for microbiological parameters are:

(a) Escherichia coli (E. coli) and coliform bacteria
     (EN ISO 9308-1 or EN ISO 9308-2)
(b) Enterococci (EN ISO 7899-2)
(c) Pseudomonas aeruginosa (EN ISO 16266)
(d) enumeration of culturable microorganisms — colony count 22 °C
     (EN ISO 6222)
(e) enumeration of culturable microorganisms — colony count 36 °C
     (EN ISO 6222)
(f) Clostridium perfringens including spores (EN ISO 14189)’;

The directive requires the member states to implement ISO 9308-2 into national legislation: According to Directive 2015/1787 EC, “Member States shall bring into force the laws, regulations and administrative provisions necessary to comply with this Directive by 27 October 2017 at the latest. They shall forthwith communicate to the Commission the text of those provisions.” As a result of the European legislation, all member states will have to accept EN ISO 9308-2 as method for the analysis of water samples of water intended for human consumption to ensure compliance with EU legislation. Germany has already implemented the new EU regulation into national law:

In Germany, the relevant law to comply with Directive 2015/1787 EC is the “Trinkwasserverordnung” (TrinkWV): “Diese Verordnung dient der Umsetzung der Richtlinie (EU) 2015/1787 der Kommission vom 06. Oktober 2015 zur Änderung der Anhänge II und III der Richtlinie 98/83/EG des Rates über die Qualität von Wasser für den menschlichen Gebrauch.“

The TrinkWV has been adapted to comply with the new EU regulation (with delay) on 03. January 2018. The new TrinkWV has been published in the “Bundesgesetzblatt” and therefore has become effective on 08. January 2018. According to § 15 (1a) Nr. 1 the following methods are to be used for the analysis of drinking water: “Coliforme Bakterien und Escherichia coli (E. coli): DIN EN ISO 9308-1:2017-09 oder DIN EN ISO 9308-2:2014-06.”

DIN EN ISO 9308-2:2014-06 states

(a) the typical composition of the medium to be used.
(b) that the circumstance, that the method has been named as  branded  by its inventor, does clearly not state exclusivity to produce and use the formulation described by EN ISO 9308-2.


The manufacturing, storage and quality control of COLIKAT RAPID is carried out by our exclusive partner Xebios Diagnostics GmbH in compliance with EN ISO 11133 and considering Good Manufacturing Practice (GMP). The quality management system is ISO 9001 certified. The quality testing of COLIKAT RAPID takes place in our EN ISO 17025 accredited laboratory complying with all requirements of EN ISO 11133 and EN ISO 9308-2. It is our goal to meet our customers’ high quality requirements at all time.

Our quality management system includes broad testing procedures for sterility, stability and shelf live, the microbiological performance and physical condition of our products. We trust only established partners which have proven to delivery according to our high quality standards for years for the sourcing of our raw materials and technical equipment.

Contact and Support

Please contact us at any time for all your questions about our products and services and for an individual quotation. You can reach our team by phone, e-mail or by using our contact form below.

HydroKat GmbH
Telleringstraße 49
40597 Düsseldorf

T : +49 211 78 88 07 – 00
E :

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