Muhterem-Uyar Meryem, Ciolacu Luminita, Wagner Karl-Heinz, Wagner Martin, Schmitz-Esser Stephan, Stessl Beatrix
Department for Farm Animals and Veterinary Public Health, Institute of Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria.
Department of Nutritional Sciences, Faculty of Life Sciences, University of Vienna, Vienna, Austria.
Front Microbiol. 2018 Feb 1;9:64. doi: 10.3389/fmicb.2018.00064. eCollection 2018.
The eradication of from food chains is still a great challenge for the food industry and control authorities since some clonal complexes (CCs) are either better adapted to food processing environments (FPEs) or are globally widespread. In this work, we focus on the in-house evolution of genotypes collected from a heavily contaminated FPE whose contamination pattern underwent a massive and yet unexplained change. At the beginning of the sampling in 2010, a high variety of most likely transient genotypes was detected belonging to sequence type (ST) 1, ST7, ST21, ST37. After several efforts to intensify the hygiene measures, the variability was reduced to ST5 that was dominant in the following years 2011 and 2012. We aimed to elucidate possible genetic mechanisms responsible for the high abundance and persistence of ST5 strains in this FPE. Therefore, we compared the genomes of six ST5 strains to the less frequently occurring transient ST37 and ST204 from the same FPE as well as the highly abundant ST1 and ST21 isolated in 2010. Whole genome analysis indicated a high degree of conservation among ST5 strains [average nucleotide identity (ANI) 99.93-99.99%; tetranucleotide correlation 0.99998-0.99999]. Slight differences in pulsed field gel electrophoresis (PFGE) patterns of two ST5 isolates could be explained by genetic changes in the tRNA-Arg-TCT prophages. ST5 and ST204 strains harbored virtually identical 91 kbp plasmids related to plasmid group 2 (pLM80 and pLMUCDL175). Interestingly, highly abundant genotypes present in the FPE in 2010 did not harbor any plasmids. The ST5 plasmids harbored an efflux pump system ( cassette) and heavy metal resistance genes possibly providing a higher tolerance to disinfectants. The pLM80 prototype plasmids most likely provide important genetic determinants for a better survival of in the FPE. We reveal short-term evolution of strains within the same FPE over a 3 year period and our results suggest that plasmids are important for the persistence of ST5 strains in this FPE.
从食物链中根除[具体病原体名称未给出]对食品行业和监管当局来说仍然是一个巨大的挑战，因为一些克隆复合体（CCs）要么更适应食品加工环境（FPEs），要么在全球广泛传播。在这项工作中，我们专注于从一个严重污染的FPE中收集的[具体病原体名称未给出]基因型的内部进化，该FPE的污染模式经历了巨大且尚未解释清楚的变化。在2010年采样开始时，检测到多种最可能是短暂存在的[具体病原体名称未给出]基因型，属于序列类型（ST）1、ST7、ST21、ST37。经过多次加强卫生措施的努力后，变异性降低到ST5，它在随后的2011年和2012年占主导地位。我们旨在阐明导致ST5菌株在该FPE中高丰度和持久性的可能遗传机制。因此，我们将六个[具体病原体名称未给出]ST5菌株的基因组与来自同一FPE的较少出现的短暂性[具体病原体名称未给出]ST37和ST204以及2010年分离出的高丰度ST1和ST21进行了比较。全基因组分析表明ST5菌株之间具有高度的保守性[平均核苷酸同一性（ANI）99.93 - 99.99%；四核苷酸相关性0.99998 - 0.99999]。两个ST5分离株的脉冲场凝胶电泳（PFGE）图谱中的细微差异可以通过tRNA - Arg - TCT前噬菌体的基因变化来解释。ST5和ST204菌株携带几乎相同的91 kbp质粒，与质粒组2（pLM80和pLMUCDL175）相关。有趣的是，2010年在FPE中存在的高丰度基因型没有携带任何质粒。ST5质粒携带一个外排泵系统（[具体基因盒名称未给出]基因盒）和重金属抗性基因，可能提供对消毒剂更高的耐受性。pLM80原型质粒很可能为[具体病原体名称未给出]在FPE中更好地存活提供重要的遗传决定因素。我们揭示了[具体病原体名称未给出]菌株在同一FPE内3年期间的短期进化，我们的结果表明质粒对于ST5菌株在该FPE中的持久性很重要。
