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Updated: Dec 27, 2025
Multiplexed Isothermal Amplification Based Diagnostic Platform to Detect Zika, Chikungunya, and Dengue 1
Published on: March 13, 2018
Multiplex loop-mediated isothermal amplification-based lateral flow dipstick for simultaneous detection of 3
Yujun Jiang1, Sihan Chen1, Yueming Zhao1
1Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China, 150000.
Abstract:
In this study, we established a rapid, simple, and sensitive method for visual and point-of-care detection of Salmonella spp., Cronobacter spp., and Staphylococcus aureus in powdered infant formula (PIF) based on multiplex loop-mediated isothermal amplification (mLAMP) combined with lateral flow dipstick (LFD). Three different species-specific target genes, siiA of Salmonella spp., internal transcribed space (ITS) of Cronobacter spp., and nuc of Staph. aureus, were applied in the mLAMP with biotin-, digoxin-, and Texas Red-modified forward inner primers and fluorescein isothiocyanate (FITC)-modified backward inner primers. After mLAMP, a large number of modified amplicons were detected with LFD; one end of the amplicon was conjugated to the anti-FITC antibody on gold nanoparticles and the other end to streptavidin (anti-digoxin or anti-Texas Red antibody) on test lines. Visual inspection of the device relies on the presence of a red band formed by accumulation of sandwich composites. The detection limits of this mLAMP-LFD assay for Salmonella spp., Cronobacter spp., and Staph. aureus in PIF without enrichment were 4.2, 2.6, and 3.4 cfu/g, respectively. The whole method can be completed in less than 1 h. Thus, mLAMP-LFD is a rapid and efficient method for simultaneously detecting Salmonella spp., Cronobacter spp., and Staph. aureus in PIF.
Insights
A new multiplex loop-mediated isothermal amplification (mLAMP) and lateral flow dipstick (LFD) method enables rapid, point-of-care detection of Salmonella, Cronobacter, and Staphylococcus aureus in powdered infant formula.
Area of Science:
- Food Safety
- Microbiology
- Biotechnology
Background:
- Powdered infant formula (PIF) is susceptible to contamination by harmful bacteria.
- Accurate and rapid detection methods are crucial for ensuring PIF safety.
- Existing methods can be time-consuming and require specialized laboratory equipment.
Purpose of the Study:
- To develop a rapid, simple, and sensitive method for simultaneous detection of three key pathogens in PIF.
- To establish a point-of-care assay for Salmonella spp., Cronobacter spp., and Staphylococcus aureus.
- To validate the multiplex loop-mediated isothermal amplification combined with lateral flow dipstick (mLAMP-LFD) assay.
Main Methods:
- Utilized multiplex loop-mediated isothermal amplification (mLAMP) targeting specific genes (siiA, ITS, nuc) for each pathogen.
- Employed species-specific primers modified with various labels (biotin, digoxin, Texas Red, FITC).
- Integrated mLAMP with lateral flow dipstick (LFD) for visual detection of amplified DNA.
Main Results:
- Achieved detection limits of 4.2 cfu/g for Salmonella spp., 2.6 cfu/g for Cronobacter spp., and 3.4 cfu/g for Staph. aureus in PIF without enrichment.
- The entire assay procedure was completed in under 1 hour.
- Demonstrated successful visual detection via a red band on the LFD device.
Conclusions:
- The mLAMP-LFD assay is a rapid, efficient, and sensitive method for simultaneous detection of Salmonella, Cronobacter, and Staph. aureus in PIF.
- This method is suitable for point-of-care testing and enhances food safety protocols.
- The assay provides a valuable tool for routine screening of powdered infant formula.
