Antibiotic Susceptibility Assay by Phenotypic Methods

Antibiotic susceptibility testing can be widely used to determine the antibiotic resistance profile of bacteria. Testing for general culture is more time consuming, thus prolonging the diagnosis of resistant bacteria. In order to combat the evolution of superbugs, we must seek technologies that can perform resistance testing quickly. High-throughput and easy-to-use phenotypic testing methods are essential for timely detection of drug resistance.

Therefore, Ace Therapeutics offers a diverse range of phenotypic methods to detect bacterial antibiotic susceptibility, as well as develops innovative resistance diagnostic techniques to address the increasing number of antibiotic resistances.

Our Antibiotic Susceptibility Assay Services

Throughout the evolutionary process, bacteria have developed multiple antibiotic resistance mechanisms. The study and development of therapies for these drug-resistant bacterial infections depends on the results of drug resistance susceptibility testing. We offer a variety of tests to report the results of antibiotic susceptibility in resistant bacteria such as MRSA (methicillin-resistant Staphylococcus aureus), VRE (vancomycin-resistant enterococci), carbapenemase-producing Enterobacterales, carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), colistin-resistant bacteria, etc., to help researchers prepare the foundation for effective antibiotic development.

We provide the following common and new techniques to help you obtain data on drug resistance.

  • Disk diffusion test. The method is based on placing different antibiotic-impregnated discs on agar inoculated with a suspension of the bacteria to be tested. Resistance results are obtained by measuring the diameter of the inhibition circle. We offer this test for screening the susceptibility of strains to a large number of antibiotics or a whole class of antibiotics, as well as for detecting certain important resistance phenotypes.
  • Dilution methods. We offer broth dilution and agar dilution methods that allow to determine the minimum concentration of antibiotics to inhibit bacterial growth and thus assess the resistance of the pathogen to a given antibiotic. This method allows simultaneous testing of different bacterial strains.
  • Chromogenic agar media test. We can develop a variety of chromogenic media to more rapidly detect and identify drug-resistant microorganisms. The different media include those for important drug-resistant organisms such as MRSA, VRE, CRAB, etc. We can ensure the quality of the media, which is essential for detection.
  • New technology platform. We offer a sensitive MALDI-TOF MS based method for bacterial identification. It allows assessment of drug-resistant bacteria such as MRSA, MSSA and others by spectral peak analysis. As well as other semi-automated or automated systems that use optical systems to measure subtle changes provide fast and reliable identification of drug resistance.

Service Quality Assurance

Standardization is a necessity in antibiotic susceptibility testing. Therefore, all of our services are evaluated to provide results of a certain quality.

  • For traditional common methods, we guarantee consistent and uniform quality of culture media, antibiotics, dilution plates and other reagent products.
  • We guarantee the proper performance of our laboratories. Control of quality is ensured through internal and external controls.
  • We perform validation of standardized protocols, test suites and software in order to obtain accurate and reliable results in the shortest possible time.

You may need a dedicated partner to support your superbug research. With Ace Therapeutics, you and your team have access to our full range of services and equipment to meet any need for drug resistance testing. Contact us and we can work together.


  1. Gajic I, et al. Antimicrobial Susceptibility Testing: A Comprehensive Review of Currently Used Methods. Antibiotics, 2022; 11(4):427.
  2. Khan Z A, et al. Current and Emerging Methods of Antibiotic Susceptibility Testing. Diagnostics, 2019; 9(2):49.
All of our services are intended for preclinical research use only and cannot be used to diagnose, treat or manage patients.
Get in touch with our team immediately.