Relationship between in vitro susceptibility test results and treatment outcomes for gram-positive mastitis pathogens following treatment with cephapirin sodium
Bibliographic record
Abstract
The selection of antimicrobial agents for the treatment of mastitis has often been based on results of in vitro susceptibility testing. However, the results of in vitro susceptibility tests have been shown to be poor predictors of treatment outcomes. The objective of this study was to determine if an association existed between results of antimicrobial susceptibility tests and outcomes of mastitis caused by gram-positive pathogens recovered from quarters that received treatment with cephapirin sodium. Mastitis pathogens were obtained from a multi-site clinical trial that evaluated the benefits of using an on-farm culturing system. Target pathogens (n = 187) comprised coagulase-negative staphylocci (65%), Streptococcus spp. (14%), other pathogens (12%), and Staphylococcus aureus (11%), which were recovered from quarters that received treatment using cephapirin sodium. The antimicrobial susceptibility profile to cephapirin was determined using the broth micro-dilution technique. The overall bacteriological cure rate achieved by cephapirin treatment was 82%. Bacteriological outcomes (cure or treatment failure) were not associated with pathogen type. A recurrent case of mastitis was observed in 10 quarters classified as cures and 3 quarters classified as treatment failures. Recurrence of mastitis was not associated with bacteriological outcomes or susceptibility test results. In vitro susceptibility to cephapirin was exhibited by 94.8 and 91.2% of pathogens recovered from quarters classified as cures and treatment failures, respectively. Bacteriological outcomes of mastitis treated using cephapirin were not associated with in vitro susceptibility test results or in vitro minimum inhibitory concentration values. In this population, there was an 82% probability of treatment success when the isolate was susceptible but only a 27% probability of treatment failure when the isolate was resistant. Based on this research, results of in vitro susceptibility tests should not be used as the primary guide for treatment decisions regarding intramammary cephapirin sodium.
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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 | 0.002 | 0.013 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".