Development of loop-mediated isothermal amplification to detect Streptococcus suis and its application to retail pork meat in Japan

作者：Arai Sakura; Tohya Mari; Yamada Ryoko; Osawa Ro; Nomoto Ryohei; Kawamura Yoshiaki; Sekizaki Tsutomu^*

来源：International Journal of Food Microbiology, 2015, 208: 35-42.

DOI：10.1016/j.ijfoodmicro.2015.05.008

• Streptococcus suis
• Pork
• LAMP

We here developed a novel loop-mediated isothermal amplification (LAMP) method to detect Streptococcus suis in raw pork meat. This method, designated LAIVIP(SS), targeted the recombination/repair protein (recN) gene of S. suis and detected all serotypes of S. suis, except those taxonomically removed from authentic S. suis, i.e., serotypes 20, 22, 26, 32, 33, and 34. The specificity of LAMP(SS) was confirmed and its detection limit was 5.4 cfu/reaction. Among the 966 raw pork meat samples examined, including sliced pork, minced pork, and the liver, tongue, heart, and small intestine, 255 samples tested positive with LAMP(SS). The rate of contamination was higher in the organs than in pork. No significant difference was observed in the total bacterial count between LAMP(SS)-positive and -negative samples. The number of shops that provided LAMP(SS)-positive pork was slightly higher in those that sold swine organs and pork than in those that sold only pork, suggesting that cross contamination occurred from the organs to pork. Among the 255 which tested positive for LAMP(SS), only 47 samples tested positive for the previously described LAMP specific for S. suis serotype 2. Two isolates of S. suis serotype 2, belonging to sequence type 28, which is potentially hazardous to humans, as well as those of some other serotypes were obtained from 19 out of 47 samples by combining LAMP with a replica plating method. These results suggest that LAMP(SS) will be a useful tool for the surveillance of raw pork meat in the retail market.

• 出版日期2015-9-2