Potential selection and maintenance of manure-originated multi-drug resistant plasmids at sub-clinical antibiotic concentrations
Bibliographic record
Abstract
ABSTRACT The goal of this study was to determine minimum selection concentrations of various antibiotics using four manure-originated multi-drug resistant plasmids in a surrogate Escherichia coli host. These plasmids carried genes conferring resistance phenotypes to several antibiotic classes including β-lactams, lincosamides, phenicols, macrolides, sulfonamides and tetracyclines. The minimum selection concentrations of antibiotics tested in nutrient-rich medium were determined: 14.1-28.2 mg/L for penicillin G, 0.1 mg/L for oxytetracycline, 0.45 mg/L for chlortetracycline, 2 mg/L for lincomycin, 1 mg/L for florfenicol, 1.3-4 mg/L for azithromycin, 0.13-0.25 mg/L for tetracycline, 0.004-0.01 mg/L for cefotaxime. Penicillin G, oxytetracycline, chlortetracycline, lincomycin and florfenicol had minimum selection concentrations in nutrient-defined medium slightly changed within 3.5-fold range compared to those in nutrient-rich medium. The minimum selection concentrations of antibiotics interfering folic acid synthesis in bacteria were also determined: 63 mg/L for sulfamethoxazole, 11.2 mg/L for sulfisoxazole and 0.06 mg/L for trimethoprim. Mixing two antibiotics changed minimum selection concentrations within 3.7-fold range compared to those in single antibiotic tests. Relatively high plasmid loss rates (> 90%) were observed when culturing plasmid-bearing strains in antibiotic-free nutrient-rich and nutrient-defined media. Overall results suggested that these plasmids can be maintained at concentrations environmentally relevant in waste water treatment plants, sewage, manure and manured soil although they are not stable in antibiotic-free environments. IMPORTANCE Antibiotic resistance crisis is a grave concern in healthcare systems around the world. To combat this crisis, we sought to find out how likely manure-originated multi-drug resistant plasmids are to be selected and maintained in different environment matrices. Our study showed that these plasmids conferring resistance to β-lactams, lincosamides, phenicols, macrolides, sulfonamides and tetracyclines can be selected at minimum selection concentrations which are lower than minimum inhibition concentrations of the E. coli host strain. Lincomycin, oxytetracycline, chlortetracycline, tetracycline, chloramphenicol, trimethoprim had minimum selection concentrations lower than the antibiotic concentrations in several environment matrices reported previously. Our findings suggest that despite the burden and the high rate of plasmid loss, these plasmids can still be selected, maintained and circulated well in some polluted environments.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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 | 0.001 | 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".