Norgen’s Swab Collection and DNA Preservation System is designed for collection, ambient storage and transport of DNA from samples collected using a swab, including nasal, buccal, saliva, fecal, skin, surfaces, etc. The Swab Collection and DNA Preservation System contains Norgen’s Swab Preservative in a liquid format. The user simply collects the specimen using the provided swab, and then transfers the swab into the Swab Preservative. The Swab Preservative prevents the growth of Gram-negative and Gram-positive bacteria and fungi, and also inactivates viruses allowing the resulting non-infectious samples to be handled and shipped safely. In addition, the Swab Preservative eliminates the need to immediately process or freeze samples and allows the samples to be shipped to centralized testing facilities at ambient temperatures. The components of the Swab Preservative allow DNA samples to be stored at room temperature for over 2 years.
DNA Isolation from Preservative
Swab samples collected and preserved using Norgen’s Swab Collection and DNA Preservation System are compatible with most DNA isolation methods. Samples stored in the tubes have been used successfully with most of Norgen Biotek’s DNA isolation kits and reagents. An optimized isolation procedure is available as part of Norgen’s Microbiome DNA Isolation Kit (Cat. 64100).
Figure 1. Stability of DNA Preserved in Norgen's Swab DNA Preservative at Room Temperature for up to 75 Months. Saliva samples were collected from numerous donors and mixed, and then an equal volume of Norgen's Swab DNA Preservative was added to the saliva. The preserved saliva was then stored at room temperature for up to 75 months. Saliva DNA was subsequently isolated at 1 week, 3 weeks, 1 month, 2 months, 4 months, 6 months, 8 months, 12 months, 20 months, 32 months, 40 months, 52 months and 75 months from 0.5 mL of the saliva/preservative sample using Norgen's Saliva DNA Isolation Kit (Cat. RU45400). For visual analysis, 100 µL of the purified DNA was run on an agarose TAE gel. As it can be seen, there is no evidence of DNA degradation after the saliva samples are stored for 75 months at ambient temperatures in Norgen's Swab DNA Preservative. Furthermore, the size of the DNA was maintained over 24 kb for the entire 75 month period. M: Norgen's UltraRanger 1 Kb DNA Ladder (Cat. 12100).
Figure 2. Detection of GAPDH Using Taqman Real-time PCR from the Saliva Samples Stored at Room Temperature from 1 Week Up to 75 Months. The quality of the saliva DNA stored at room temperature did not change from 1 week to 75 months, as indicated by the fact that the Ct values remained consistent. The improvement in the Ct values from the real-time PCR graph (red) also indicate the impact of the improved saliva DNA isolation method provided by the Saliva DNA Isolation Kit (Cat. RU45400).
Figure 3. Real Time PCR Amplification of Saliva DNA from the saliva samples stored at room temperature from 1 week up to 75 months (13 time points). All isolated saliva DNA samples were successfully amplified without any sign of PCR inhibition. Blue: Saliva DNA isolated using improved Saliva DNA Isolation Kit (Cat. RU45400). Black: No template control.
Figure 4. Illumina MiSeq 16s rRNA metagenomics data from saliva samples preserved for over 6 years using Norgen's Swab DNA Preservative. The saliva DNA was isolated using Norgen's Saliva DNA Isolation Kit (Cat. RU45400) from saliva that had been preserved for various periods of time up to 6 years at room temperature. A) Principal Coordinate Analysis of 12 saliva microbiomes showing differences in the distribution of taxonomic classifications between samples up to kingdom level. B) Hierarchical clustering of 12 saliva microbiomes based on genus-level classifications, including a bar chart showing the relative abundance of genus-level classifications for each sample in the dendrogram.
When stored at room temperature, unused Norgen Swab Preservative Tubes are stable through to the collect-before date without any reduction in performance. Please see the device insert or tube label for collect-before date.