Evidence map›Paper›PMID 34843501›Full record

ArticlePloS one2021

Absolute quantification of E. coli virulence and housekeeping genes to determine pathogen loads in enumerated environmental samples.

K B Hoorzook, T G Barnard

Open access · goldAbstract read
In one paragraph

Article in PloS one, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
0.3field-weighted citation impact, top 43% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed, 6 citations in OpenAlex.

  1. DietaryAnimals : an open access journal from MDPI · 2025
    Article
  2. Review
  3. Article
  4. Genomic insights ofFrontiers in microbiology · 2022
    Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

2 authors at 1 institution in 1 country.

K B HoorzookWater and Health Research Centre, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa.ORCID 0000-0002-1296-6975
T G BarnardWater and Health Research Centre, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa.
University of Johannesburg · ZA

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Quantifying pathogenic genes with q-PCR in complex samples to determine the pathogen loads is influenced by a wide range of factors, including choice of extraction method, standard curve, and the decision to use relative versus absolute quantification of the genes. The aim was to investigate the standardisation of q-PCR methods to determine enumerated E. coli gene ratios grown with the IDEXX Colilert® Quanti-Trays® using enteropathogenic E. coli as the model pathogen. q-PCR targeting the eaeA and gadAB genes was used to calculate the eaeA: gadAB ratios for clinical strains collected between [2005-2006 (n = 55)] and [2008-2009 (n = 19)] using the LinRegPCR software and Corbett Research Thermal cycler software. Both programs grouped the isolates into two distinct groups based on the gene ratios although the Corbett Research Thermal cycler software gave results one log higher than the LinRegPCR program. Although the eaeA: gadAB ratio range was determined using extracted E. coli DNA, the impact of free DNA and other bacteria present in the sample needed to be understood. Standard curve variations using serially diluted extracted E. coli DNA, serially diluted pure E. coli culture followed by DNA extraction from each dilution with or without other bacteria was tested using the eaeA q-PCR to quantify the genes. Comparison of the standard curves showed no significant difference between standard curves prepared with diluted DNA or with cells diluted before the DNA is extracted (P = 0.435). Significant differences were observed when background DNA was included in the diluent or Coliform cells added to the diluent to dilute cells before the DNA is extracted (P < 0.001). The "carrier" DNA and Coliform cells enhanced the DNA extraction results resulting in better PCR efficiency. This will have an influence on the quantification of gene ratios and pathogen load in samples containing lower numbers of E. coli.

Indexed as

Environmental MonitoringEscherichia coliEscherichia coli ProteinsGene Expression ProfilingGenes, EssentialHumansNucleic Acid Amplification TechniquesPolymerase Chain ReactionTranscriptomeVirulenceEscherichia coli Proteins

Identifiers

PMID34843501
PMCPMC8629182
OpenAlexW3215561016

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.