Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us
LGC Clinical Diagnostics

Download Mobile App




A Series of Sensitive and Specific DNA-Based Assays Detects and Differentiates Salmonella Serotypes

By LabMedica International staff writers
Posted on 07 May 2020
A team of Australian researchers developed a series of sensitive and specific assays to detect and identify different serotypes (serovars) of Salmonella, a common cause of bacterial foodborne disease worldwide.

Rapid, accurate, and sensitive identification of Salmonella serovars is vital for diagnosis and public health surveillance. In this regard, an isothermal amplification technique, called multiple cross-displacement amplification (MCDA), has been employed to detect Salmonella at the species level.

MCDA is a non-PCR based DNA amplification technique. This method can rapidly amplify minute amounts of DNA samples to a reasonable quantity for genomic analysis. The reaction starts by annealing random hexamer primers to the template: DNA synthesis is carried out by a high fidelity DNA polymerase enzyme at a constant temperature. Compared with conventional PCR amplification techniques, MCDA generates larger sized products with a lower error frequency. This method has been actively used in whole genome amplification (WGA) and is a promising method for application to single cell genome sequencing and sequencing-based genetic studies.

Investigators at the University of New South Wales (Sydney, Australia) developed seven MCDA assays and evaluated them for their capability to rapidly detect and differentiate the five most common Salmonella serovars in Australia: Typhimurium, Enteritidis, Virchow, Saintpaul, and Infantis. MCDA primer sets were designed by targeting seven serovar/lineage-specific gene markers identified through genomic comparisons. The sensitivity and specificity of the seven MCDA assays were evaluated using 79 target strains and 32 nontarget strains.

Results revealed that the assays were all highly sensitive and specific to target serovars, with the sensitivity ranging from 92.9% to 100% and the specificity from 93.3% to 100%. The limit of detection of the seven MCDA assays was 50 femtograms per reaction (10 copies) from pure DNA, and positive results were detected in as little as eight minutes.

"Salmonella in a clinical or food sample may be present in very small amounts and thus requires very sensitive methods to detect them. Multiple cross-displacement amplification (MCDA) is a method that can detect very small amounts of DNA rapidly and is also performed at a single constant temperature, in contrast to the cycling of temperatures required in other methods such as PCR. This makes it a good fit for a simple, rapid, and sensitive bacterial detection test. Although an MCDA test for any Salmonella already exists, it does not distinguish between different serotypes," said senior author Dr. Ruiting Lan, professor of biotechnology and biomolecular sciences at the University of New South Wales. "The assays developed in this study are unique because the gene markers used were selected based on analyzing thousands of genomes. Thus, these markers future proof Salmonella serotyping in the era of culture-independent diagnostic testing."

The Salmonella serovars assays were described in the April 28, 2020, online edition of The Journal of Molecular Diagnostics.

Related Links:
University of New South Wales


Gold Member
Serological Pipet Controller
PIPETBOY GENIUS
Verification Panels for Assay Development & QC
Seroconversion Panels
New
HIV Test
Anti-HIV (1/2) Rapid Test Kit
New
Total 25-Hydroxyvitamin D₂ & D₃ Assay
25-OH-VD Reagent Kit
Read the full article by registering today, it's FREE! It's Free!
Register now for FREE to LabMedica.com and get access to news and events that shape the world of Clinical Laboratory Medicine.
  • Free digital version edition of LabMedica International sent by email on regular basis
  • Free print version of LabMedica International magazine (available only outside USA and Canada).
  • Free and unlimited access to back issues of LabMedica International in digital format
  • Free LabMedica International Newsletter sent every week containing the latest news
  • Free breaking news sent via email
  • Free access to Events Calendar
  • Free access to LinkXpress new product services
  • REGISTRATION IS FREE AND EASY!
Click here to Register








Channels

Clinical Chemistry

view channel
Image: The tiny clay-based materials can be customized for a range of medical applications (Photo courtesy of Angira Roy and Sam O’Keefe)

‘Brilliantly Luminous’ Nanoscale Chemical Tool to Improve Disease Detection

Thousands of commercially available glowing molecules known as fluorophores are commonly used in medical imaging, disease detection, biomarker tagging, and chemical analysis. They are also integral in... Read more

Immunology

view channel
Image: The cancer stem cell test can accurately choose more effective treatments (Photo courtesy of University of Cincinnati)

Stem Cell Test Predicts Treatment Outcome for Patients with Platinum-Resistant Ovarian Cancer

Epithelial ovarian cancer frequently responds to chemotherapy initially, but eventually, the tumor develops resistance to the therapy, leading to regrowth. This resistance is partially due to the activation... Read more

Pathology

view channel
Image: The ready-to-use DUB enzyme assay kits accelerate routine DUB activity assays without compromising data quality (Photo courtesy of Adobe Stock)

Sensitive and Specific DUB Enzyme Assay Kits Require Minimal Setup Without Substrate Preparation

Ubiquitination and deubiquitination are two important physiological processes in the ubiquitin-proteasome system, responsible for protein degradation in cells. Deubiquitinating (DUB) enzymes contain around... Read more

Technology

view channel
Image: The HIV-1 self-testing chip will be capable of selectively detecting HIV in whole blood samples (Photo courtesy of Shutterstock)

Disposable Microchip Technology Could Selectively Detect HIV in Whole Blood Samples

As of the end of 2023, approximately 40 million people globally were living with HIV, and around 630,000 individuals died from AIDS-related illnesses that same year. Despite a substantial decline in deaths... Read more

Industry

view channel
Image: The collaboration aims to leverage Oxford Nanopore\'s sequencing platform and Cepheid\'s GeneXpert system to advance the field of sequencing for infectious diseases (Photo courtesy of Cepheid)

Cepheid and Oxford Nanopore Technologies Partner on Advancing Automated Sequencing-Based Solutions

Cepheid (Sunnyvale, CA, USA), a leading molecular diagnostics company, and Oxford Nanopore Technologies (Oxford, UK), the company behind a new generation of sequencing-based molecular analysis technologies,... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.