Listeria monocytogenes is a Gram-positive bacterium, commonly found in food, water or sewage. This microorganism is capable of forming biofilm on different surfaces such as steel, glass, polypropylene etc. Recently an increase in cases of listeriosis has been noted, making L. monocytogenes the important health threat. Therefore, there is a need for rapid and sensitive detection of this pathogen. This study aimed to compare the number of L. monocytogenes cells recovered from the biofilm (prepared on steel and polypropylene) using the detection and amplification of the hlyA gene (droplet digital PCR, ddPCR) and the classical culture method. The research material consisted of 96 L. monocytogenes strains. A total of 58 isolates were obtained from clinical samples and 38 isolates derived from the municipal sewage treatment plant. Additionally, the reference strain ATCC®19111™ (WDCM00020) was used. The Pearson correlation coefficient for the results obtained by the classical culture-based method and ddPCR was 0.864 and 0.725, for biofilms produced on AISI 304 stainless steel surface and the polypropylene surface, respectively. Correlations were statistically significant (p ≤ 0.001), indicating that the ddPCR technique is an effective tool for the assessment of bacteria number in the biofilm.

中文翻译：

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使用经典的基于培养的方法和数字液滴PCR比较单核细胞增生李斯特菌形成生物膜的强度。

单核细胞增生李斯特菌是革兰氏阳性细菌，通常存在于食物，水或污水中。这种微生物能够在钢，玻璃，聚丙烯等不同表面上形成生物膜。最近发现李斯特菌病病例增加，这使单核细胞增生李斯特菌成为重要的健康威胁。因此，需要快速和灵敏地检测该病原体。这项研究旨在通过检测和扩增hlyA基因（液滴数字PCR，ddPCR）和经典培养方法，比较从生物膜（在钢和聚丙烯上制备）回收的单核细胞增生李斯特菌细胞的数量。研究材料由96个单核细胞增生李斯特菌菌株组成。从临床样品中总共获得了58种分离株，从市政污水处理厂获得了38种分离株。另外，使用参考菌株19111 TM（WDCM00020）。对于基于AISI 304不锈钢表面和聚丙烯表面的生物膜，通过基于经典培养的方法和ddPCR获得的结果的皮尔逊相关系数分别为0.864和0.725。相关性具有统计学意义（p≤0.001），表明ddPCR技术是评估生物膜中细菌数量的有效工具。