The capacity of real-time PCR (RT-PCR), the VIDAS immunoassay system, and the conventional count method for detecting Salmonella enterica serovar Typhimurium and Listeria monocytogenes biofilm cells was evaluated in this study. After biofilm formation, tests were performed under different drying times (0, 6, 12, 24, and 72 h) and pre-enrichment times (0, 6, 18, and 25 h). The direct epifluorescence microscopic results demonstrated that Salmonella Typhimurium and L. monocytogenes biofilm cells can remain viable for 72 h under drying conditions. Pre-enrichment time and type of medium played an essential role in the detection of both microorganisms after drying. Furthermore, RT-PCR was more sensitive than VIDAS and the conventional method for detecting Salmonella Typhimurium and L. monocytogenes cells at different drying times and without pre-enrichment (0 h), with a detection range between 102 and 107 CFU/mL. TSBYE-T80 used as a pre-enrichment medium was effective for detecting both bacteria and was more effective than Demi Fraser-T80 medium for detecting L. monocytogenes. Therefore, pre-enrichment is recommended to avoid false positives and false negatives due to the presence of dead cells or a very low initial concentration of cells after drying.

中文翻译：

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使用常规和快速方法检测暴露于不同干燥和预富集时间的鼠伤寒沙门氏菌和单核细胞增生李斯特菌生物膜细胞。

本研究评估了实时PCR（RT-PCR），VIDAS免疫测定系统和常规计数方法检测肠炎沙门氏菌血清鼠伤寒沙门氏菌和单核细胞增生李斯特菌生物膜细胞的能力。生物膜形成后，在不同的干燥时间（0、6、12、24和72小时）和预富集时间（0、6、18和25小时）下进行测试。直接的表观荧光显微镜结果表明，鼠伤寒沙门氏菌和单核细胞增生李斯特菌生物膜细胞在干燥条件下可以存活72小时。干燥后，预富集时间和培养基类型对两种微生物的检测都起着至关重要的作用。此外，RT-PCR比VIDAS和检测鼠伤寒沙门氏菌和L的常规方法更为敏感。单核细胞增生细胞在不同的干燥时间且没有预富集（0 h），检测范围在102和107 CFU / mL之间。用作预富集培养基的TSBYE-T80可有效检测两种细菌，并且比Demi Fraser-T80培养基可更有效地检测单核细胞增生李斯特氏菌。因此，建议进行预富集以避免由于死细胞的存在或干燥后细胞初始浓度非常低而导致的假阳性和假阴性。