Viable Nonculturable Discordance
Screen discordance between viability assay and matched culturability; this pattern alone does not prove a VBNC state.
Description
Viability and culture assays measure different properties.
Viability and culture assays measure different properties. High viability with low culturability can be a discordant pattern, but that pattern alone does not establish a viable-but-nonculturable state.1
Screen discordance between viability assay and matched culturability; this pattern alone does not prove a VBNC state.
When to use Viable Nonculturable Discordance
Use this tool to screen discordance between viability assay and matched culturability; this pattern alone does not prove a VBNC state.
Prepare the sample, count, growth or assay measurements requested by this tool. Confirm units, sampling periods and reporting bases; supply independently established comparison criteria where requested.
How to use Viable Nonculturable Discordance and understand its results
- Prepare the sample, count, growth or assay measurements requested by this tool. Confirm units, sampling periods and reporting bases; supply independently established comparison criteria where requested.
- Enter viabilityAssayLive, viabilityAssayTotal, culturableCount, matchedTotalCount, minimumLiveFraction, maximumCulturableFraction using the field table and calculation rules, then run the tool.
- Read liveFraction, culturableFraction, discordantViabilityPattern. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| viabilityAssayLive | Viability assay live | integer; minimum: 0 | Required |
| viabilityAssayTotal | Viability assay total | integer; minimum: 1 | Required |
| culturableCount | Culturable count | integer; minimum: 0 | Required |
| matchedTotalCount | Matched total count | integer; minimum: 1 | Required |
| minimumLiveFraction | Minimum live fraction | number; minimum: 0; maximum: 1 | Required |
| maximumCulturableFraction | Maximum culturable fraction | number; minimum: 0; maximum: 1 | Required |
Enter nonnegative integer numerators and positive integer denominators, each numerator no greater than its matching total. Choose thresholds in [0,1]. The tool reports both fractions and flags liveFraction at least the minimum together with culturability at most the maximum. Both comparisons include equality.
liveFraction = live/assayedTotal; cultureFraction = culturable/matchedTotal Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| liveFraction | Live fraction | number |
| culturableFraction | Culturable fraction | number |
| discordantViabilityPattern | Discordant viability pattern | boolean |
{
"input": {
"viabilityAssayLive": 90,
"viabilityAssayTotal": 100,
"culturableCount": 2,
"matchedTotalCount": 100,
"minimumLiveFraction": 0.8,
"maximumCulturableFraction": 0.05
},
"output": {
"liveFraction": 0.9,
"culturableFraction": 0.02,
"discordantViabilityPattern": true
}
}Limitations and assumptions
The assays must describe comparable populations. Assay specificity, injury, aggregation and culture conditions are not analyzed, so a passing pattern is not a mechanistic diagnosis.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.
Alternative or Complementary methods
Use Gram Mixture Control Audit: Screen mixed Gram-stain cell-color observations with a supplied minority criterion and control validity; mixture does not distinguish contamination from Gram variability. For a complementary task, use Biofilm Biomass Normalized Adhesion: Normalize blank-corrected crystal-violet stain OD by matched biomass OD to compare adhesion among cultures.
References
-
Viable Nonculturable Discordance — tool.io
Similar or alternative tools
- Gram Mixture Control Audit
Screen mixed Gram-stain cell-color observations with a supplied minority criterion and control validity; mixture does not distinguish contamination from Gram variability.
- Biofilm Biomass Normalized Adhesion
Normalize blank-corrected crystal-violet stain OD by matched biomass OD to compare adhesion among cultures.