Isolation and Characterization of Virulence Genes and Antimicrobial Resistance of Escherichia coli from Urban Stormwater
Bibliographic record
Abstract
The objectives of this study were to isolate E. coli from stormwater, detect virulence genes (VGs) associated with intestinal (InPEC) and extraintestinal pathogenic E. coli (ExPEC), and evaluate antimicrobial resistance. In addition, the proportion of tetracycline-resistance E. coli in stormwater and their multidrug resistance (MDR) was determined. Presumptive E. coli (n=770) were isolated from water samples (n=83) collected weekly between August to September from stormwater retention ponds in Alberta, Canada. VGs associated with InPEC (eaeA, ehxA, bfpA, aggR, ipaH, STa, and LT) and ExPEC (sfa/foc, fimH, papC, fyuA, iutA, iroN, cnf1, and hlyA) were assessed using multiplex and single PCR. Moreover, tetracycline-resistant E. coli were isolated using tetracycline-embedded (1µg/ml – 4µg/ml) agar plates via replica plating. Subsequently, the clonal relatedness of E. coli isolates was determined via repetitive extragenic palindromic sequence PCR. Then, antimicrobial susceptibility testing was performed using the Sensititre CMV4AGNF plates. Among the 761 confirmed E. coli isolates, 17 (2.2%) carried the adhesion VG, eaeA. In addition, 4 (0.53%), 719 (95%), and 1 (0.13%) were positive for ExPEC fimbrial/pili adhesin VGs, sfa/foc, fimH, and papC, respectively. Furthermore, iron acquisition genes were also detected, including fyuA (13%), iutA (0.80%), and iroN (13%), with the proportion of iroN and iutA positive isolates significantly different (P < 0.001 and P < 0.0018) between two sites. The toxin gene, cnf1 (0.13%), was also detected. Among the isolates carrying the eaeA gene and >3 ExPEC VGs, 24% were resistant to antimicrobials, including tetracycline, ampicillin, and streptomycin. Finally, the proportion of tetracycline-resistant E. coli in stormwater samples (n=83) was 44%. Of these, 47% and 70% of unique isolates from Site 1 and Site 2 were resistant to more than two antimicrobials, with most isolates also resistant to streptomycin (33%-50%) and ampicillin (30%-45%). Multiple antimicrobial resistance (MAR) index patterns indicated MDR isolates may originate from high-risk sources in both sites.This study provided an insight into the microbial quality of stormwater concerning the prevalence of antibiotic-resistant and VG harbouring E. coli. These results may help develop practical microbial management strategies imperative to prevent potential public health risks associated with stormwater reuse for irrigation of public spaces.
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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) | 0.001 | 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 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".