Department of Applied Sciences, Northumbria University, Newcastle upon Tyne, UK.
UCD-Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.
J Appl Microbiol. 2021 Nov;131(5):2082-2094. doi: 10.1111/jam.15089. Epub 2021 Apr 3.
Listeria species may colonize and persist in food processing facilities for prolonged periods of time, despite hygiene interventions in place. To understand the genetic factors contributing to persistence of Listeria strains, this study undertook a comparative analysis of seven persistent and six presumed non-persistent strains, isolated from a single food processing environment, to identify genetic markers correlating to promoting persistence of Listeria strains, through whole genome sequence analysis.
A diverse pool of genetic markers relevant to hygiene tolerance was identified, including disinfectant resistance markers qacH, emrC and the efflux cassette bcrABC. Both persistent and presumed non-persistent cohorts encoded a range of stress resistance markers, including heavy metal resistance, oxidative and pH stress, although trends were associated with each cohort (e.g., qacH and cadA1C resistance was more frequently found in persistent isolates). Persistent isolates were more likely to contain mutations associated with attenuated virulence, including a truncated InlA. Plasmids and transposons were widespread between cohorts.
Results suggest that no single genetic marker identified was universally responsible for a strain's ability to persist. Persistent strains were more likely to harbour mutation associated with hypovirulence.
This study provides additional insights into the distribution of genetic elements relevant to persistence across Listeria species, as well as strain virulence potential.
李斯特菌属的物种可能会在食品加工设施中长时间定植和持续存在，尽管采取了卫生干预措施。为了了解导致李斯特菌菌株持续存在的遗传因素，本研究对从单一食品加工环境中分离出的 7 株持续性菌株和 6 株假定非持续性菌株进行了比较分析，通过全基因组序列分析，确定与促进李斯特菌菌株持续存在相关的遗传标记。
确定了一组与卫生耐受性相关的遗传标记，包括消毒剂抗性标记 qacH、emrC 和外排盒 bcrABC。持续性和假定非持续性队列都编码了一系列应激抗性标记，包括重金属抗性、氧化和 pH 应激，尽管趋势与每个队列相关（例如，qacH 和 cadA1C 抗性在持续性分离株中更为常见）。持续性分离株更有可能含有与减弱毒力相关的突变，包括截短的 InlA。质粒和转座子在两个队列之间广泛存在。
结果表明，没有一个单一的遗传标记可以普遍决定菌株持续存在的能力。持续性菌株更有可能携带与低毒力相关的突变。
本研究提供了更多关于与李斯特菌属物种持续性相关的遗传元件以及菌株毒力潜力分布的信息。
