A LAMP Assay has been developed which rapidly detects a troublesome food pathogen called Yersinia.
The gram negative rod, bacterium Yersinia pseudotuberculosis has been a troublesome pathogen (Okwori et al., 2009) causing various intestinal diseases especially post-infections following surgery. Most notably, acute enteritis and gastritis, reactive arthritis and erythema nodosum and the outbreaks are world-wide (Zadernomska et al., 2014). The main route for infection is via the oral-faecal route but infection occurs through contaminated water, various meats such as pork, and especially through dairy products such as milk (Shwimmer et al., 2007). The microorganism is related to another troublesome bacterium called Yersinia enterolitica and the cause of Bubonic plague, Yersinia pestis.
One of the issues as with all detection methods for microorganisms, is developing a rapid assay and that appears to have improved immeasurably for Yersinia. Using a loop-mediated isothermal amplification (LAMP) assay, a Chinese-Canadian research group have speeded up this method further for Yersinia targeting the 16S-23S rDNA internal transcribed spacer (ITS) region (Zhang et al., 2014). The length and base sequence of the ITS region is unique to each species making it a powerful target for assay. The method relies as in many cases on DNA amplification which is now completed in less than 1 hour and is 100 times more sensitive than the conventional polymerase chain reaction (PCR) method. A positive result for Yersinia occurs with the formation of a white precipitate. They assessed 236 commercial milk powders and correctly identified 18 cases from that sample. The PCR method has been a standard technique for identifying many microorganisms and the LAMP method may well improve upon this for other bacteria as well according to this research group.
References
Okwori, A.E., Martınez, P.O., Fredriksson-Ahomaa, M., Agina, S.E., Korkeala, H. (2009) Pathogenic Yersinia enterocolitica 2/O:9 and Yersinia pseudotuberculosis 1/O:1 strains isolated from human and non-human sources in the Plateau State of Nigeria. Food Microbiol . 26 pp. 872–5.
Shwimmer A, Freed M, Blum S, Khatib N,Weissblit L, Friedman S, EladD. (2007) Mastitis caused by Yersinia pseudotuberculosis in Israeli dairy cattle and public health implications. Zoonoses Public Health 547.
Xue, R., Du, X-J., Lu, X., Wang, S. (2014) Loop-Mediated Isothermal Amplification Assays for Detecting Yersinia pseudotuberculosis in Milk Powders. J. Food Sci. 79(5) M967-M971
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p align=”LEFT”>Zadernowska, A., Chajecka-Wierzchowska, W. & Laniewska-Trokenheim, L. (2014) Yersinia enterocolitica: a dangerious, but often ignored, foodborne pathogen. Food Rev. Int. 30 pp. 53-70
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