French Agency for Food, Environmental, and Occupational Health & Safety, Maisons-Alfort Laboratory for Food Safety, Bacterial Characterization and Epidemiology Unit, European Union Reference Laboratory for Listeria monocytogenes, Maisons-Alfort Cedex, France.
Foodborne Pathog Dis. 2012 Aug;9(8):719-26. doi: 10.1089/fpd.2011.1124.
The European Union Reference Laboratory for Listeria monocytogenes (EURL for L. monocytogenes) coordinates a European network of 29 National Reference Laboratories (NRLs). Depending on a national decision, NRLs undertake food, environmental, and veterinary L. monocytogenes strain surveillance in their respective countries. In the framework of the PulseNet Europe network, two pulsed-field gel electrophoresis (PFGE) subtyping proficiency testing (PT) trials were carried out in 2003 and 2006. The obtained data showed that PFGE profiles can be compared and exchanged between laboratories. However, no further PT trial had been performed since 2006. In this context, two PT trials were organized by the EURL to evaluate the ability of NRLs to perform conventional serotyping, molecular serotyping and PFGE subtyping. Eleven well-characterized isolates of L. monocytogenes were used: six and nine isolates were tested in 2009 and 2010, respectively. Three isolates were repeated between the two studies. In the 2010 panel, a strain was tested in duplicate, and two strains were related to the same epidemiological group. The strains were analyzed blind in different laboratories (17 in 2009 and 25 in 2010) using (1) their own in-house method for serotyping methods and (2) standardized protocols based on the PulseNet protocol for PFGE. For conventional serotyping, 86.0% in 2009 and 91.0% in 2010 of the serotypes obtained were in agreement with the EURL data. For molecular serotyping, 93.5% of the results in 2009 and 95.2% in 2010 matched the EURL data. For PFGE, 68.9% in 2009 and 81.7% of the combined AscI/ApaI profiles were indistinguishable from the EURL reference profiles. The variations observed could be attributed to slight standardization defaults or, in a few cases, to a failure in DNA extraction. These PT trials provided a valuable opportunity to improve the subtyping ability of NRLs and facilitate exchanges of subtyping data in the future.
欧盟单核细胞增生李斯特菌参考实验室（EURL for L. monocytogenes）协调着一个由 29 个国家参考实验室（NRLs）组成的欧洲网络。根据国家决策，NRLs 在各自国家开展食品、环境和兽医单核细胞增生李斯特菌菌株监测。在 PulseNet Europe 网络框架内，2003 年和 2006 年进行了两次脉冲场凝胶电泳（PFGE）分子分型能力验证（PT）试验。获得的数据表明，PFGE 图谱可在实验室之间进行比较和交换。然而，自 2006 年以来，没有再进行进一步的 PT 试验。在这种情况下，EURL 组织了两次 PT 试验，以评估 NRL 进行常规血清分型、分子血清分型和 PFGE 分子分型的能力。使用了 11 种经过良好特征描述的单核细胞增生李斯特菌分离株：2009 年和 2010 年分别测试了 6 个和 9 个分离株。两个研究之间重复了 3 个分离株。在 2010 年的试验中，一个菌株进行了重复测试，两个菌株与同一流行病学组有关。这些菌株在不同的实验室中进行了盲法分析（2009 年 17 个，2010 年 25 个），使用（1）他们自己的内部血清分型方法和（2）基于脉冲网协议的标准化协议进行 PFGE。对于常规血清分型，2009 年和 2010 年获得的血清型中分别有 86.0%和 91.0%与 EURL 数据一致。对于分子血清分型，2009 年和 2010 年的结果中有 93.5%和 95.2%与 EURL 数据相匹配。对于 PFGE，2009 年和 2010 年的 AscI/ApaI 图谱组合中，分别有 68.9%和 81.7%的图谱与 EURL 参考图谱无法区分。观察到的变化可能归因于轻微的标准化缺陷，或者在少数情况下归因于 DNA 提取失败。这些 PT 试验为提高 NRL 的分型能力提供了宝贵的机会，并为未来交换分型数据提供了便利。
