Rapid Antibiotic Susceptibility Testing via Electrochemical Measurement of Ferricyanide Reduction by <i>Escherichia </i><i>c</i><i>oli</i> and <i>Clostridium </i><i>s</i><i>porogenes</i>
Bibliographic record
Abstract
Electrochemical measurement of respiratory chain activity allows rapid and reliable screening for antibiotic susceptibility in microorganisms. Chronoamperometry and chronocoulometry of suspensions of aerobically cultivated E. coli combined with the non-native oxidant potassium hexacyanoferrate(III) (ferricyanide) yield signals for reoxidation of the reduction product ferrocyanide that are much smaller if the E. coli has been incubated briefly with an effective antibiotic compound. Chronocoulometric results, obtained following 20-min incubation with antibiotic and 2-min measurement in assay buffer containing 50 mM ferricyanide and 10 mM succinate, at +0.50 V vs Ag/AgCl at a Pt working electrode, were compared with traditional disk diffusion susceptibility testing, which requires overnight incubation on agar plates; the results show significantly lower accumulation of ferrocyanide in all cases in which growth inhibition was observed in the disk diffusion assay. A range of antibiotic compounds (13) were examined that possess different mechanisms of action. Quantitative determination of IC50 values for penicillin G and chloramphenicol yielded values that were 100-fold higher than those obtained by standard turbidity methods after 10-h incubation; this is likely a result of the very brief (10 min) exposure time to the antibiotics. Addition of 5 microM 2,6-dichlorophenolindophenol, a hydrophobic electron-transfer mediator, to the assay mixture allowed susceptibility testing of a Gram-positive obligate anaerobe, Clostridium sporogenes. This rapid new assay will facilitate clinical susceptibility testing, allowing appropriate treatment virtually as soon as a clinical isolate can be obtained.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".