Increased Expression of AbcA Efflux Pump Accelerated Resistance Development from Tolerance to Resistance Against Oxacillin in Staphylococcus aureus
Bibliographic record
Abstract
Bacterial tolerance, especially in Staphylococcus aureus (S. aureus), may arise under intermittent antibiotic regimens and act as a stepping stone toward resistance development. However, the transition from tolerance to resistance and its contributing factors remain poorly understood. This study explores the role of the efflux pump gene abcA in this process. abcA mutants (overexpression, knockout, and complementation) were constructed via homologous recombination. These strains were subjected to 21 cycles of intermittent exposure to oxacillin at 20× MIC, and the resistance evolution was monitored. Spontaneous mutation frequencies and survival abilities in these mutants were also measured to determine their involvement in resistance development. The abcA overexpression mutant exhibited a faster development of resistance compared to the wildtype strain. Conversely, the abcA knockout mutant maintained susceptibility to oxacillin, with no significant changes in the relative MIC. Increased mutation frequency and enhanced survival were observed in the overexpression strain, whereas both were reduced in the knockout. abcA overexpression significantly accelerated the development of oxacillin resistance in S. aureus by promoting spontaneous mutations and bacterial survival. Disrupting abcA may offer a novel strategy to prevent the evolution of antibiotic resistance.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".