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Antibacterial & Antifungal Testing

Delivering Standard and Custom Assays

We provide quality antibacterial and antifungal testing services integral to the discovery, development, and registration of new antimicrobial agents. Our testing services include screening/susceptibility testing, lead characterization studies, test method development, and characterization / ID.

Our scientists have a broad range of technical expertise in antimicrobial research and development from discovery all the way through the regulatory submission and review process. Contact us for standard and custom assays to meet your unique needs.

Quality antibacterial and antifungal testing.

Learn more about these services.

Screening / Susceptibility Testing

We offer high throughput screening, primary and secondary profiling, and a repository of clinical isolates.

Repository of Clinical Isolates

Recent clinical isolates of prevalent Gram-positive and negative pathogens, including anaerobic pathogens along with fungi available for screening. Isolates with genetically characterized resistance mechanisms (e.g. KPC, NDM-1, OXA) also available.

High Throughput Screening

Microbiologics has conducted a variety of high throughput screens of compound collections using the Biomek 3000/Biomek FX platforms. We offer whole cell screens of bacteria, yeast, and fungi utilizing compound collections arrayed in 96-well plates. In addition, we offer end points of whole cell screens which can include either MIC values, absorbance of culture readings using a Spectramax, or Alamar Blue readings, as well as enzymatic screens using compound collections.

Primary Profiling (spectrum of activity) and Secondary Profiling (MIC50/MIC90)

To characterize the spectrum of activity of the lead compound or further differentiate between lead compounds based on MIC, primary profiling is offered by performing susceptibility testing on a diverse group of clinically relevant Gram-positive and Gram-negative pathogens, including anaerobes and fungi if applicable. Secondary profiling studies are then conducted to understand the activity of the lead compound against representative population of target pathogens at volumes sufficient to understand the MIC50/MIC90.

Susceptibility Testing Methodology (CLSI M2, M7, and M100)
  • Broth Microdilution MIC Testing: Custom panels are created using a 96-well format. Compounds can be provided as dry powders or as solutions.
  • Agar Dilution MIC Testing: Compounds can be provided as dry powders or as solutions.
  • Disk Diffusion Testing: Using manufactured disks or disks made in house.

Lead Characterization Studies

Microbiologics provides lead characterization studies including mechanism of action, in vitro pharmactodynamics, and development of resistance.

Mechanism of Action Studies

Determining the mechanism of action (MOA) of new agents is essential to the discovery process and is also a required component of the Investigational New Drug (IND) filing. Microbiologics utilizes a variety of whole cell, molecular, and biochemical techniques to determine the MOA. We provide macromolecular synthesis inhibition, transcription/translation assay (cell-free), cell-lysis assay (ATP leakage, RBC lysis), and enzyme assays (IC50 studies).

In Vitro Pharmacodynamic Studies

Following CLSI protocols, Microbiologics conducts an assessment of an antimicrobial agent’s ability to kill or suppress growth of target organisms using the following assays (assays conducted in accordance with CLSI M26, where applicable): time-kill, MBC/MFC, serum bactericidal titer, and post-antibiotic effect.

Development of Resistance Studies

An assessment of the ability of bacteria to develop resistance to new agents is an important early consideration in the discovery phase. Microbiologics provides spontaneous mutation frequency (SMF) assays and serial passage assays.

Test Method Development

We provide tier 1 quality control and parameter studies, tier 2 broth/agar MIC and disk quality control studies, disk diffusion development, and method correlation studies.

Tier 1 Quality Control and Parameter Studies (CLSI M23)

Evaluation of testing parameters on in vitro activity (e.g. pH, inoculum size, cation concentration, protein binding/activity and serum, etc.).

Development of preliminary Tier 1 Quality Control Ranges at a single test laboratory in accordance with CLSI M23.

Tier 2 Broth/Agar MIC and Disk CLSI M23 Quality Control Studies

Multi-laboratory study to establish QC ranges of new agents in accordance with CLSI M23 and including presentation to the QC working group.

Disk Diffusion/Alternate Test Methods Development and/or Evaluation

Method Correlation Studies
(broth vs. disk, agar vs. broth, etc.).


We provide bacterial and fungal culture identification, isolation and molecular biology services.


Isolation of a variety of organisms from a given test sample across a variety of matrices such as skin swab, fecal, urine, tissue, etc.

Bacterial/Fungal ID
  • Bruker MALDI Biotyper
  • 16S rRNA gene sequencing
  • DuPont Riboprinter
  • Crystal ID (BBL Crystal ID)
Molecular (PFGE, PCR, Sequencing)

Our team is highly experienced in the application of a variety of molecular biology techniques that aid the discovery and development process:

  • PCR of genes involved in resistance and/or target identification
  • DNA sequencing for mutational analysis or for 16S rRNA identification
  • Bioinformatics to align sequences and provide a comparison to reference genes
  • Pulsed field gel electrophoresis for analysis of patient isolates (treatment failures) and epidemiological typing (e.g. USA typing of S. aureus)

Connect with the Antibacterial and Antifungal Team

We’re ready to answer your questions.

Business Development
Phone: +1.800.599.2847
Email: businessdevelopment@microbiologics.com

We are the world’s leading experts and go-to collaborators for biological products and services.

Learn more about our capabilities and areas of expertise at each of our locations.