243. Transflection Fourier Transform Infrared Spectroscopy as a Real-Time Strain Typing Technique: A Vancomycin-Resistant Enterococcus faecium (VRE) Typing Prospective Study
Bibliographic record
Abstract
Abstract Background Rapid bacterial strain typing for nosocomial outbreak surveillance is critical for timely outbreak detection and implementation of appropriate infection control protocols in hospitals. Pulsed-field gel electrophoresis (PFGE) remains the gold standard for strain typing, but it has the disadvantages of being time-consuming and costly. Transflection Fourier transform infrared (FTIR) spectroscopy is a nondestructive and reagent-free technique for rapid microbial identification and subspecies-level discrimination. The potential of employing transflection FTIR spectroscopy as a rapid, real-time typing technique was evaluated in the present study. Methods Transflection FTIR spectra were acquired from vancomycin-resistant Enterococcus faecium (VRE) isolates obtained from rectal swabs (n = 36) of patients in 6 units at a Montreal hospital over a 3-month period and from environmental screening samples (n = 2). Upon confirmation as VRE using a transflection FTIR spectral database previously developed in our laboratory, isolates were further typed by unsupervised hierarchical cluster analysis and principal component analysis of the FTIR spectral data with the use of a feature selection algorithm. Results Analysis of the FTIR data identified independent cases of VRE outbreak in 2 of 6 units; these outbreaks were confirmed retrospectively by PFGE. Based on the PFGE typing results for all 38 isolates included in this study, FTIR spectral analyses successfully identified 95% (n = 18) of isolates related to the outbreaks and 95% (n = 18) of non-outbreak-related isolates, resulting in a false-positive (n = 1), and a false-negative (n = 1), rate of 5%. Additionally, the two environmental isolates were identified as part of the outbreak from one of the outbreak-positive units. Conclusion The results in this study indicate that transflection FTIR spectroscopy-based typing can be considered as an alternative typing technique to PFGE, providing real-time results to track the spread of antibiotic-resistant pathogens within hospitals. Furthermore, when combined with the use of a transflection FTIR spectral database, both identification and typing of an isolate can be achieved from a single spectral measurement, thereby reducing the time and cost required for outbreak investigation. Disclosures All authors: No reported disclosures.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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 teacher head, 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".