Anti-infectives In Vitro Testing

Charles River can quantify the effect of your antiviral and antimicrobial test compounds on the growth and infectivity of a wide range of bacteria and viruses using standardized assays. We work with many bacterial pathogens to help you to calculate the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill values for your antibiotics, resistance modifiers, and virulence modulators. We offer cell-based assays, including internalization and killing and biofilms.

Our in vitro team can provide support for your in vivo efficacy studies to enumerate bacterial load in tissues following treatment. Our virologists are experienced with every stage of antiviral and vaccine development, including propagating viruses, determining viral titres, and testing the efficacy of your antivirals. We use cell culture viability assays and plaque assays to test lead compounds as part of in vitro viral screening programs or in support of in vivo models.


Expedited In Vitro Antiviral Screen

Expedited in vitro assays can be used to screen novel and existing anti-viral therapies which are targeted against coronavirus and other viral strains that can be handled at a BSL2 safety level.

The effective concentration of compound resulting in 50% reduction in viral infectivity on cells (EC50) can be assessed following determination of 50% cytoxicity concentration (CC50). Potential efficacy can be determined for many viral strains, including the HCoV-229E Alphacoronavirus and the HCoV-OC43 coronavirus strain, a BSL2 Betacoronavirus. These strains provide a useful screening tool for novel viral therapies directed at the COVID-19 strain which is a Betacoronavirus (BSL3, pandemic strain).

Antimicrobial in vitro bacterial assays include:

  • MIC assays (minimum inhibitory concentration)
  • MBC assays (minimum bactericidal concentration)
  • Time-kill assays
  • In vitro pharmacokinetic and pharmacodynamics assays
  • Resistance testing
  • Cell-based assays (internalization and killing and biofilm assays)
  • Immune modulation assays (ELISA, Luminex, and FACS)

Antiviral in vitro assays include:

  • TCID50 assay
  • EC50 /CC50 assay
  • Plaque assays
  • HAI assays (hemagglutination inhibition)
  • ELISA/Luminex

In vitro testing of antimicrobial compounds can determine potential efficacy in an in vivo anti-infective model and provide important data to determine optimal dosing regimen and combination ratios.

chart showing correlation of AUC against AUCCFU of E. coli and S. aureus

Figure 1: Determination of pharmacokinetic drivers in infection showing correlation of AUC against AUCCFU of E. coli and S. aureus

chart showing Increase in percentage killing of P. aeruginosa internalised in 16HBE cells

Figure 2: Increase in percentage killing of P. aeruginosa internalized in 16HBE cells following antimicrobial treatment compared with untreated control (**P<0.01, unpaired t-test)


Frequently Asked Questions (FAQs) in Antiviral and Antimicrobial Research:


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