Procedure for in vitro evaluation of antimicrobial compounds against <i>Lawsonia intracellularis</i>
Bibliographic record
Abstract
Lawsonia intracellularis is an obligate intracellular bacterium invading the intestinal epithelium. The culture conditions for L. intracellularis make evaluation of antimicrobial compounds challenging. This study demonstrates an in vitro procedure to evaluate antimicrobial efficacy using green tea extract (-)-epigallocatechin-3-gallate (EGCG) as a test compound. To evaluate EGCG's effect on extracellular bacteria, infectivity of L. intracellularis (PHE MN-100) exposed to EGCG or control media was assessed using mouse fibroblast (McCoy) cells. Lawsonia intracellularis in media was quantified by qPCR and in cells by immunostaining at 3- and 5-days post infection (dpi). As no safe dose of EGCG for intestinal epithelial cells is established, enteroids (swine-derived organoids) were exposed to varying concentrations of EGCG. Cell viability indicated a safe dose of ≤500 nM EGCG. To evaluate EGCG's effect on intracellular bacteria, enteroid monolayers were infected. At 3-dpi, enteroids were treated with up to 500 nM EGCG . Lawsonia intracellularis in media was quantified every 48 h by qPCR. Presence of L. intracellularis was evaluated by immunostaining cells at 5-, 7-, and 14-dpi. Although we found no differences in L. intracellularis infection when treated with EGCG, the procedures are useful to evaluate safety and efficacy of antimicrobial compounds on obligate intracellular bacteria in vitro.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.003 |
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".