Susceptibility determination and customized configuration

Antimicrobial susceptibility determination and configuration of antibiotics as specified by the customer

Antimicrobial susceptibility determination

The test principle of the MICRONAUT system for antimicrobial susceptibility testing (AST) is based on phenotypic detection of resistance as expressed by microbial growth in presence of antibiotic compounds. This micro dilution procedure is a standardized method and a worldwide accepted reference system for determination of the minimal inhibitory concentration (MIC).

Customer-specific configuration of antibiotics

  • MIC study plates available in various formats
  • Large selection of human and veterinary antibiotics and antifungals  
  • Synergy testing by antibiotic combinations
  • Variable concentration ranges
  • Implementation of single or multi test plates
  • Production of variable quantities
  • Short delivery times of 8 to 12 weeks


P E G - Paul-Ehrlich-Gesellschaft für Chemotherapie e.V.

The PEG-resistance study project consists of a major multi center MIC study and a minor multi center blood culture MIC study which is performed separately. Goal of this project is to monitor drug resistance among clinical relevant pathogens in Germany and Central Europe.

Data collection is performed in 3 year intervals as an average sample and is conducted with MICRONAUT-S MIC plates in 96 well micro plate format.

EU reference laboratory for antimicrobial resistance external quality assurance system (EQAS) 2013

External Quality Assurance System (EQAS) on antimicrobial susceptibility testing

The organisation and implementation of an External Quality Assurance System (EQAS) on antimicrobial susceptibility testing (AST) of E. coli, enterococci and staphylococci, and identification and typing of MRSA is among the tasks of the EU Reference Laboratory for Antimicrobial Resistance (EURL-AR).

This EQAS aims to support laboratories to assess and, if necessary, to improve the quality of results obtained by AST of pathogens of food- and animal-origin, with special regard to E. coli, enterococci and staphylococci.


The project “Quality Assurance Exercises and Networking on the Detection of Highly Infectious Pathogens” (QUANDHIP), funded by the European Commission as a Joint Action (JA) since 1st August 2011 (EAHC n° 2010 21 02), aims to link and consolidate the objectives of two existing European networks: The “European Network for Highly Pathogenic Bacteria“ (ENHPB) has been set up in the framework of the previous EU funded project “Establishment of Quality Assurances for Detection of Highly Pathogenic Bacteria of Potential Bioterrorism Risk” (EQADeBa), coordinated by the Robert Koch-Institut (RKI), Germany (EAHC n° 2007 204), and the “European Network of P4 Laboratories (ENP4Lab), which also came into being as an EU project, coordinated by L.Spallanzani National Institute for Infectious Diseases (INMI), Italy (EAHC n° 2006 208).



EUCAST mentions MERLIN on page 11 in this presentation:

Compliance of manufacturers of AST materials and devices with EUCAST guidelines


MERLIN regularly participates in interlaboratory tests of the INSTAND e.V. and is named as reference laboratory for bacteriology. In addition, MERLIN is listed as manufacturer in the related catalog.


LABOKLIN, the laboratory for clinical diagnostics, is known as having one of the broadest spectrum of self-executed and accredited veterinary tests.

In this context are used our MICRONAUT plates as well as our software. More about their specific test environment here

MERLIN | A Bruker Company

MERLIN becomes Bruker's Center of Excellence for MALDI Biotyper-based AST

Bruker acquires MERLIN to add Selected Antibiotic Resistence and Susceptability Testing to its MALDI Biotyper® Microbial Identification Platform

26.07.2017  |  Dr. Esther Pfeil, Managing Director of MERLIN Diagnostika GmbH, commented this acquisition: "We are very pleased to be part of Bruker's microbiology business now, as we have been collaborating with Bruker already for several years. Our product and service offerings in the field of antibiotic susceptibility testing (AST) complement the MALDI Biotyper system for fast and efficient microbial identification. With our proven expertise in the field of AST, we aim to accelerate further assay additions to the MBT-STAR™ consumables portfolio for selected, rapid antibiotic resistance and susceptibility testing on the MALDI Biotyper."

MERLIN will continue to serve all existing collaboration and distribution partners, as well as all OEM customers and end customers after the acquisition.

Further details about MERLIN’s acquisition by Bruker are provided in this press release.


UMIC® Cefiderocol

31.08.2022  |  From a drug development perspective, cefiderocol is one of the most promising antibiotics, remaining active even when facing the most challenging carbapenem resistance mechanisms. To support antibiotic stewardship, clinical microbiologists are looking for reliable and accurate cefiderocol MIC testing in full compliance with EUCAST and CLSI standards. Bruker's UMIC® Cefiderocol and the associated iron-depleted Mueller Hinton broth offer an easy to implement solution and can conveniently be tested along with UMIC® Colistin to deliver trusted MIC results when it matters most.

For more information, please visit Bruker's website.

Legal Manufacturer Change

From January 2022 the MICRONAUT products have been transferred from MERLIN Gesellschaft fuer mikrobiologische Diagnostika mbH to Bruker Daltonics GmbH & Co. KG as legal manufacturer.

EUCAST warns against the use of vancomycin gradient tests for MIC determination!

21.05.2019  |  EUCAST warns against the use of gradient tests for vancomycin MIC determination, since this causes false susceptibility. EUCAST recommends products based on broth microdilution procedure as method of choice for vancomycin MIC determination to confirm vanB low-level resistance in Enterococcus faecalis and Enterococcus faecium. (ref. MIC-Strip Vancomycin/Teicoplanin).
More information about the difficulties in the EUCAST vancomycin susceptibiliy testing

NEW | MICRONAUT-S Carbapenemases Detection

11.09.2018  |  The new two-test-plate MICRONAUT-S Carbapenemases Detection, which is based on broth microdilution procedure, provides phenotypic detection of clinically relevant carbapenemases (type A carbapenemases (e.g. KPC), metallo-β-lactamases, and OXA-48-like type D carbapenemases) in enterobacteria and Pseudomonas aeruginosa.

  • NEW: Phenotypic confirmatory assay of OXA-48-like type D carbapenemases in enterobacteria by the new inhibitor combination meropenem / avibactam and determination of high-level temocillin resistance.
  • Two isolates can be tested per plate.

The layout of this special plate is available on request.

Dr. Esther Pfeil elected as a member of the German CCI General Assembly

01.01.2017  |  Last autumn, Dr. Esther Pfeil, Managing Director of MERLIN Diagnostika GmbH, took part in the election to the General Assembly of the chamber of commerce and industry Bonn / Rhein-Sieg. Since January 1st, 2017, she is representing the interests of the manufacturing industry in the Rhein-Sieg area for five years at the General Assembly. Dr. Pfeil decided to present herself as a candidate "since I am a managing director of an SME, I would like to take responsibility for the strengthening of small and medium-sized enterprises (SMEs) and their employees in our region. Subjects, of which I feel touched and which I would like to move forward, are the enhancement of market ability through innovation, the expansion of existing training and development programs to promote skilled workers, and the reconcilability of family and work."



EUCAST warning regarding Colistin susceptibility testing

28.11.2016 | Thanks to our microdilution procedure, EUCAST recommends our MICRONAUT products for Colistin testing!

More information about the difficulties in the EUCAST Colistin susceptibility testing

MICRONAUT-UR | update with the new antibiotic Mecillinam

19.10.2016  |  The plate MICRONAUT-UR, which is used in the bacteriological laboratory diagnostics for urology, is from now on available with an improved antibiotics spectrum. It has been enriched by the new antibiotic Mecillinam.

NRW subsidies for the joint research project "PathoSept"

MERLIN is among the winners in the key market competition LifeSciences.NRW

01.08.2016 | MERLIN Diagnostika is one of the winners of the first round in the key market competition LifeSciences.NRW: Referees voted for the joint research project "PathoSept", which is intended to save many lives by rapidly diagnosing threatening infections.

In the key market competition LifeSciences.NRW, 10 joint projects were selected from 51 contest entries, which will be funded with a total of 19.3 million euros.

"Winner is also our project 'PathoSept', with which we want to create a diagnostic complete system under the coordination of the Fraunhofer Institute for Applied Information Technology. It very quickly identifies pathogenic agents of life-threatening infections and simultaneously allows a quantitative determination of the antibiotic resistance profile. Based on these results, it can be initiated a targeted individual antibiotic therapy no later than nine hours", says Dr. Esther Pfeil, Managing Director of MERLIN Diagnostika.

In addition to the Fraunhofer Institute and MERLIN, the companies Carpegen GmbH, based in Münster, and Jüke Systemtechnik GmbH as well as the university clinics of Aachen and Bonn, belong to the network. The volume of this project is about 3.5 million euros.

Every year, more than 56,000 people die from sepsis in Germany, one of the most severe bacterial infections that can be even simply caused by a purulent tooth. Currently, the time between suspected diagnosis and targeted therapy can last up to five days, and infections with multiresistant pathogens can not be adequately treated. PathoSept is intended to open up the reliable diagnosis after nine hours, thus significantly reducing the high mortality rate, but above all the new generation and spread of multiresistant pathogens, as well as the intensive medical costs. With this an infection can be treated very early in the process and very specifically.

MERLIN has already made essential preparations for this project because we are specialized in the development, validation and marketing of various microbiological diagnostic systems for the qualitative and quantitative detection of microbial antibiotic resistance. MERLIN's diagnostic systems for quantitative susceptibility testing allow the determination of the minimum inhibitory concentration (MIC value) in accordance with the normative requirements. These systems are supplemented by phenotypic detection methods for the detection of clinically and epidemiologically relevant resistance mechanisms. MERLIN also has a great expertise in the handling of antimicrobial agents, which are meaningful in the validation of the manufacture, packaging, storage and application of antibiotic-containing diagnostics. "These are core competencies that make a decisive contribution to the successful implementation of the joint research project," emphasizes Dr. Esther Pfeil.

MERLIN is continuing the development of its products and processes, taking into account sustainability as well as environmental and economic aspects, with the aim of implementing the Antibiotic Stewardship for the rational use of the anti-infectives.



MICRONAUT-S | first AST product with the new antibiotics combinations of Ceftazidim/Avibactam and Ceftolozan/Tazobactam

24.05.2016 | MICRONAUT-S MDR MRGN Screening, the updated MIC plate for the susceptibility testing of multi-resistant gramnegative bacteria (multidrug resistance phenotype), has been enriched with these new features:

  • Expanded antibiotic spectrum by introducing the new antibiotic combinations Ceftazidim / Avibactam and Ceftolozan / Tazobactam
  • Expanded antibiotic spectrum by introducing Meropenem screening concentrations for improved detection of OXA-48-like type D carbapenemases

MICRONAUT-S MDR MRGN Screening provides, based on the microdilution method, the phenotypic detection of clinically relevant resistance mechanisms in enterobacteria and nonfermenters, including the detection of cephalosporinases and carbapenemases.

MICRONAUT-S ß-Lactamases | optimized detection of OXA-48

16.03.2016 | The phenotypic detection of multiple ß-lactamases (multiple resistance determinants) in the single test system has been extended:

MICRONAUT-S β-Lactamases provides, based on the microdilution method, the phenotypic detection  of clinically relevant cephalosporinases and carbapenemases in entero-bacteria and non-fermenters.

  • Detection of OXA-48-like type D carbapenemases by the determination of high-level Temocillin resistance
  • Detection of low-level carbapenem resistance by introduction of Ertapenem / Meropenem screening concentrations

The layout of these special plates is available upon request.