Survival of<i>Escherichia coli</i>O157:H7 in feces from corn- and barley-fed steers
Bibliographic record
Abstract
The survival of Escherichia coli O157:H7 in feces from steers fed corn (CO) or barley (BA) was evaluated at -10, +4 and +22 degrees C. Fecal pats were inoculated with a four-strain mixture of nalidixic-acid resistant E. coli O157:H7 at two levels: 10(3) CFU g(-1) (low, L) and 105 CFU g(-1) (high, H). At -10 degrees C, duration of survival of E. coli O157:H7 was reduced (p < 0.05) in CO-L (35 days) compared to BA-L (49 days), likely due to the effects of fecal volatile fatty acids in combination with a fecal pH of <6.5. At 4 degrees C, E. coli O157:H7 was detected in BA-H, CO-H, CO-L and BA-L for 77, 77, 56 and 63 days, respectively, with no difference (p > 0.05) observed in the duration of survival or rate of decline of E. coli O157:H7 among treatments. Survival of E. coli O157:H7 was twice as likely (p < 0.05) at 22 degrees C than at 4 degrees C and -10 degrees C. While pH and dry matter content increased, and volatile fatty acid concentrations decreased over 84 days at all three temperatures, these changes were most pronounced at 22 degrees C. Survival of E. coli O157:H7 for extended periods of time in feces from both corn- and barley-fed animals was demonstrated, thus fecal material may serve as a vector for the transmission of the organism. The greater survival of E. coli O157:H7 at 22 degrees C suggests that temperature may play a role in the seasonality of transmission and prevalence of this bacterium in feedlot cattle. The reported greater prevalence of E. coli O157:H7 in cattle fed barley as compared to those fed corn does not appear to be related to elevated risk of transmission arising from differential survival of the bacterium in feces.
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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 | 0.000 | 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".