Phages against porcine post-weaning diarrhea due to O149 Escherichia coli
Bibliographic record
Abstract
The objective of this study was to isolate, characterize, and evaluate phages that might be used in prevention and treatment of porcine post-weaning diarrhea due to O149 enterotoxigenic 'E. coli' (ETEC). Serotype O149:H10 was especially targeted because this is the dominant ETEC serotype and strains are highly virulent. Six phages (N1-N6) that lysed O149:H10 ETEC and three (O7-O9) that lysed O149:H43 ETEC were isolated from pig sewage from Ontario pig farms. Phages Nl-N6 lysed 99-100% of 85 O149:H10 ETEC, 0-12% of 42 O149:H43 ETEC, 3-35% of 37 non-O149 porcine ETEC, and 6-68% of the 72 strains of the ECOR collection. Phages O7-O9 lysed 86-98% of the O149:H43 ETEC, 2-53% of the O149:H10 ETEC, and 24-41% of the non-O149 porcine ETEC. The phages were susceptible to extremes of pH. All nine phages had necks and contractile tails typical of the 'Myoviridae.' The estimated genome sizes of phages Nl-N6 were 42-50 kb. Phage N1 was shown to consist of a circularly permuted genome of 52,976 bp, with terminal repeats and a G+C content of 44%. There were 75 putative genes, all reading from left to right on the same DNA strand. There was no integrase gene and no 'attp' region. The phage was unique as the genes involved in morphogenesis were related to genes of the ' Myoviridae' whereas the remaining genes were related to genes of the T7 group of phages belonging to the 'Podoviridae.' Phages N1-N6 individually and a combination of phages N1, N2, and O7 were investigated for their effectiveness as a prophylactic measure in weaned pigs that were concurrently challenged with an O149:H10 ETEC. Also, a mixture of phages N1 and N6 was evaluated as therapy after diarrhea developed following a similar experimental challenge. In both modes, individually and in combination, administration of the phages typically resulted in improvement in weight gain, and reduction in the duration and severity of diarrhea, and decreased excretion of the challenge ETEC as compared with the control pigs. These studies indicate that the N phages are good candidates for development for prophylactic and therapeutic strategies for O149:H10 ETEC diarrhea in weaned pigs.
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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 | 0.000 | 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 | 0.000 | 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 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".