Evaluation of the Bruker MALDI Biotyper (MBT) subtyping module for detection of <i>Klebsiella pneumoniae</i> carbapenemase (KPC) in <i>Enterobacterales</i> in a Canadian clinical microbiology laboratory
Bibliographic record
Abstract
ABSTRACT Early detection of Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales enables prompt initiation of appropriate antimicrobial therapy and infection prevention and control measures. The matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) Biotyper (MBT) Subtyping Module (Bruker Daltonics) uses a characteristic spectral peak at ~11,109 m/z to identify KPC-producing Enterobacterales . The aim of this study was to assess the ability of the MBT Module to detect KPC among a variety of clinical and reference (AR Bank) Enterobacterales isolates. Detection of KPC was compared between the MBT Module and a laboratory-developed real-time KPC PCR. Of the 93 isolates tested, 58 (62.4%) were positive for KPC by PCR (39 clinical and 19 AR bank isolates), and 35 were negative. Among the KPC-positive PCR isolates, nine (seven clinical and two AR bank) also tested positive for KPC by the MBT Module. KPC detection via the MBT Module had a sensitivity of 15.5% and a specificity and positive predictive value of 100%. This study also assessed the performance of the MBT Module to detect KPC-2 versus KPC-3 among the AR Bank isolates. The MBT Module detected 2/5 (40.0%) KPC-2 and 0/14 of KPC-3 AR Bank isolates. As sensitivity was low, but specificity was high, a positive MBT Module result reliably predicts the presence of KPC; however, negative results cannot be relied upon to be truly KPC-negative. IMPORTANCE Enterobacterales , a large order of pathogenic and commensal bacteria, can gain resistance to carbapenems through the acquisition of plasmids carrying genes, such as Klebsiella pneumoniae carbapenemase (KPC). Early detection of KPC is crucial for patient care; however, current detection methods that involve multiple time-consuming steps, commonly only undertaken after overnight susceptibility testing, indicate possible carbapenem resistance. This study examined the ability of matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF), a common diagnostic tool in the clinical laboratory, to detect KPC among Enterobacterales . KPC detection via MALDI-ToF had low sensitivity but 100% specificity. These results support and expand the microbiological and geographical range of prior publications for this tool. A practical application of this highly specific method would involve rapid triaging of KPC-positive isolates a day earlier than current methods, permitting initiation of more timely therapeutic and infection prevention and control measures.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.002 | 0.001 |
| 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".