Dipartimento di Patologia Animale, Ispezione degli Alimenti di Origine Animale, Università degli Studi di Torino, Facoltà di Medicina Veterinaria, Via Leonardo da Vinci 44, 10095 Grugliasco, Torino, Italy.
Int J Food Microbiol. 2010 Jun 15;140(2-3):271-6. doi: 10.1016/j.ijfoodmicro.2010.04.016. Epub 2010 Apr 21.
Listeria monocytogenes can cause severe invasive disease in humans and has been isolated from a variety of foods. This study aimed to investigate type diversity and distribution across sources by subtyping via PFGE a set of 300 L. monocytogenes isolates collected in Italy from foods over a five year period (from 2003 to 2007). The most frequent serotypes were 1/2a (45%), 1/2c (22%), and 4b/4e (16%); 5% of the isolates were untypeable by conventional serotyping. Significant associations were observed between serotype 1/2a with dairy (O.R.=13.9) and 1/2c with meat (O.R.=33.3). All isolates were typeable, generating 164 combined PFGE profiles. Of these, 121 were unique, being displayed by only one isolate. The other 43 profiles grouped the remaining isolates and were shared between two (N=22), three (N=10), four (N=3) and five isolates (N=4). The remaining 4 profiles were shared between 7, 14, 17 and 46 isolates, respectively. Some profiles (N=7) were retrieved in samples collected in different years, indicating persistency in foods and processing plants. This research may pose the ground for designing a broad typing database which could ease the understanding of L. monocytogenes diversity and could be used for facilitating epidemiological investigations for the identification of listeriosis outbreaks. Data show how large subtype databases may facilitate the identification of common and source-specific types. More comprehensive databases may be needed to fully understand L. monocytogenes diversity and to provide useful data to be considered in epidemiological investigations.
单增李斯特菌可引起人类严重的侵袭性疾病，已从各种食品中分离出来。本研究旨在通过 PFGE 对意大利在五年期间（2003 年至 2007 年）从食品中收集的 300 株李斯特菌分离株进行亚型分析，以调查其型别多样性和来源分布。最常见的血清型为 1/2a（45%）、1/2c（22%）和 4b/4e（16%）；5%的分离株通过常规血清分型无法定型。1/2a 型与乳制品（O.R.=13.9）和 1/2c 型与肉类（O.R.=33.3）之间存在显著关联。所有分离株均可定型，产生 164 种组合 PFGE 图谱。其中 121 种是独特的，仅由一种分离株显示。其余 43 种图谱则将其余的分离株分组，并在两个（N=22）、三个（N=10）、四个（N=3）和五个（N=4）分离株之间共享。其余 4 种图谱分别在 7、14、17 和 46 个分离株之间共享。一些图谱（N=7）在不同年份采集的样本中被检出，表明其在食品和加工工厂中存在持久性。这项研究可能为设计广泛的分型数据库奠定基础，从而有助于理解李斯特菌的多样性，并可用于促进流行病学调查，以确定李斯特菌病的暴发。数据表明，大型亚型数据库如何有助于识别常见和来源特异性的类型。为了全面了解李斯特菌的多样性，并为流行病学调查提供有用的数据，可能需要更全面的数据库。
