Characterization of extended-spectrum -lactamase-producing isolates of Haemophilus parainfluenzae
Bibliographic record
Abstract
OBJECTIVES: To characterize the beta-lactam resistance mechanisms of two clinical isolates of cefotaxime-resistant Haemophilus parainfluenzae recovered from patients in South Africa. METHODS: The relatedness of isolates and plasmids was assessed using PFGE and restriction enzyme analysis, respectively. Plasmid-mediated and chromosomally integrated bla(TEM) genes and ftsI genes were sequenced, and the plasmid-mediated bla(TEM-15) was used to transform a range of control organisms. RESULTS: The two isolates were found to be unique according to PFGE, but had an identical 3.7 kb plasmid encoding a TEM-15 beta-lactamase. Both isolates also had substitutions in penicillin binding protein 3 (PBP3) consistent with substitutions known to exist in beta-lactamase-negative ampicillin-resistant (BLNAR) strains of Haemophilus influenzae. The cefotaxime MICs for control strains of H. influenzae, H. parainfluenzae and BLNAR H. influenzae transformed with the plasmid-mediated bla(TEM-15) were 1.0, 1.0 and 4.0 mg/L, respectively, compared with 16.0 and 8.0 mg/L, respectively, for the two parent H. parainfluenzae. CONCLUSIONS: The high-level cefotaxime resistance in the H. parainfluenzae isolates was due to a combination of a plasmid-mediated TEM-15 extended-spectrum beta-lactamase with altered PBP3 probably contributing. Other contributing resistance mechanisms could not be excluded.
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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) | 0.001 | 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".