Unique monitoring of biofilm formation based on metabolic activity

The calScreener™ is the only existing technology able to determine both the formation of biofilm as well as the effect of treatment based on metabolic response

  • Determination of biofilm formation in different materials independently of the shape or morphology
  • Monitoring of the effect of one antibiotic or any combination of compounds in the pre-formed biofilm
  • Monitoring of the effect of different antibiofilm compounds
  • Reliable life-death measurement of the three-dimensional biofilm structure
  • Native biofilm conditions
  • Formation and antimicrobial testing of polymicrobial biofilm

Different thermogram depending on bacterial type of growth

Planktonic and biofilm growth

The shown thermograms are from two different P. aeruginosa strains cultured in the same media and conditions. Planktonic growth characteristically returns to very low metabolic activity after the depletion of nutrients in the media (WT). Biofilm forming strains can be shown to select a different path where the metabolic rate is sustained at a low but continuous level for a more extended period (cystic fibrosis). The calScreener™ easily differentiates the tendency to form viable biofilm.

The calScreener™ is the first assay that allows continuous label-free monitoring of biofilm formation and treatment analysis irrespective of sample morphology

It is estimated by the National Institutes of Health (NHI) that biofilm-forming bacteria cause 80% of the infections in humans. These microorganisms generate an extracellular matrix that allows them to attach to each other and produce a physically stable three-dimensional structure. This microenvironment is protected from the host phagocytes, and the accessibility and susceptibility to antibiotics is decreased. It is, in fact calculated, that to target biofilms, between 50 and 500 times more minimum inhibitory concentration (MIC) is needed, as compared to targeting the same bacteria in their planktonic state.

With the calScreener™, different, clinical relevant treatments could be screened

  • Antibiotic minimal inhibitory concentration (MIC)
  • Minimum biofilm inhibitory concentration
  • Minimal biofilm eradication concentration
  • Biofilm bactericidal concentration
  • Biofilm prevention concentration

Real time monitoring of biofilm formation using native conditions

The formation of biofilm can be monitored to produced consistent pre-formed biofilm starting levels for treatment analysis.

*Data courtesy from Dr. van Wamel, Erasmus Medical Center, The Netherlands.

Reliable monitoring of treatment effect on preformed biofilm

Pre-formed biofilm can be treated with antibiotics in single or combination treatment as well as in combination with potentiating agents. The graph shows the effect an antibiotic treatment on the metabolic rate of preformed biofilm.

*Data courtesy from Dr. van Wamel, Erasmus Medical Center, The Netherlands.

A picture of Willem van Wamel who is from the Erasmus medical center

Asst. Prof. Willem van Wamel

Head of the Staphylococcus Group, Medical Microbiology Department at Erasmus MC

"Isothermal microcalorimetry allows us to observe in real-time the metabolic status of biofilm associated bacteria and therefore to select the antibiotics that are active against them."

The calScreener has already been used to study biofilm cariogenic bacteria

Scientific References

Caries-associated biofilms induce loss of calcium from tooth surfaces in the presence of dietary carbohydrates. Exopolysaccharides (EPS) provide a matrix scaffold and an abundance of primary binding sites within biofilms. The role of EPS in binding calcium in cariogenic biofilms is only partially understood. Thus, the aim of the present study is to investigate the relationship between the calcium dissolution rates and calcium tolerance of caries-associated bacteria and yeast as well as to examine the properties of EPS to quantify its binding affinity for dissolved calcium. Calcium dissolution was measured by dissolution zones on Pikovskaya’s agar. Calcium tolerance was assessed by isothermal microcalorimetry (IMC) by adding CaCl2 to the bacterial cultures. Acid-base titration and Fourier transform infrared (FTIR) spectroscopy were used to identify possible functional groups responsible for calcium binding, which was assessed by isothermal titration calorimetry (ITC). Lactobacillus spp. and mutans streptococci demonstrated calcium dissolution in the presence of different carbohydrates. All strains that demonstrated high dissolution rates also revealed higher rates of calcium tolerance by IMC. In addition, acidic functional groups were predominantly identified as possible binding sites for calcium ions by acid-base titration and FTIR. Finally, ITC revealed EPS to have a higher binding affinity for calcium compared, for example, to lactic acid. In conclusion, this study illustrates the role of EPS in terms of the calcium tolerance of cariogenic microbiota by determining the ability of EPS to control free calcium concentrations within the biofilms as a self-regulating mode of action in the pathogenesis of dental caries.

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