Alves Frederico, Nunes Alexandra, Castro Rita, Sequeira António, Moreira Olga, Matias Rui, Rodrigues João Carlos, Silveira Leonor, Gomes João Paulo, Oleastro Mónica
Infectious Diseases Department, National Institute of Health Dr. Ricardo Jorge (INSA), Lisbon, Portugal.
Faculty of Veterinary Medicine, Lusófona University, Lisbon, Portugal.
Front Microbiol. 2022 Apr 14;13:858310. doi: 10.3389/fmicb.2022.858310. eCollection 2022.
The recent increase in community-acquired infections discloses the shift in this bacterium epidemiology. This study aimed at establishing a transmission network involving One Health components, as well as assessing the zoonotic potential and genomic features of dominant clones. Samples were collected from different compartments of animal, human and environmental origin, from an animal production unit. isolates were characterized for toxigenic profile by multiplex-PCR, while genetic diversity was evaluated by PCR-ribotyping and whole genome-based analysis. The overall prevalence was 37.2% (70/188), and included samples from environmental (58.3%, 35/60) and animal (31.5%, 35/111) compartments; human samples ( = 17) taken from healthy workers were negative. A predominant clone from RT033 was found in almost 90% of the positive samples, including samples from all compartments connected to the pig production unit, with core-genome single nucleotide variant (SNV)-based Analysis supporting a clonal transmission between them (mean distance of 0.1 ± 0.1 core-SNVs). The isolates from this clone (herein designated PT RT033) were positive for all toxin genes (). The phyloGenetic positioning of this clone was clearly distinct from the classical RT033 cluster, suggesting a different evolutionary route. This new clone shares genomic features with several RTs from the clade 5 Sequence Type (ST) 11, including a complete pathogenicity locus (PaLoc) that is more similar to the one found in toxigenic strains and contrasting to the less virulent classical RT033 ( + +). The presence of a gene truncated into two ORFs, not previously described, requires further evaluation concerning toxin functionality. We hypothesize that the unique combination of genetic elements found in the PT RT033 clone may contribute to host tropism and environmental dissemination and maintenance. This study constitutes the first report of a toxigenic RT033 clone and adds to the overall knowledge on Clade 5 sequence type 11, considered the evolutionary lineage with the highest zoonotic potential. The presence of this clone in all compartments associated with the pig production unit suggests a transmission chain involving these animals and contributes to unveil the role played by animal and environmental reservoirs in this pathogen epidemiology.
近期社区获得性感染的增加揭示了这种细菌流行病学的转变。本研究旨在建立一个涉及“同一健康”各组成部分的传播网络，并评估优势克隆的人畜共患病潜力和基因组特征。从一个动物生产单位采集了来自动物、人类和环境来源的不同区室的样本。通过多重聚合酶链反应（PCR）对分离株的产毒谱进行表征，同时通过PCR核糖体分型和基于全基因组的分析评估遗传多样性。总体患病率为37.2%（70/188），包括来自环境区室（58.3%，35/60）和动物区室（31.5%，35/111）的样本；从健康工人采集的人类样本（n = 17）均为阴性。在几乎90%的阳性样本中发现了一个来自RT033的优势克隆，包括来自与生猪生产单位相关的所有区室的样本，基于核心基因组单核苷酸变异（SNV）的分析支持它们之间的克隆传播（平均距离为0.1±0.1个核心SNV）。来自该克隆的分离株（在此指定为PT RT⁰³³）所有毒素基因均呈阳性（此处原文缺失具体毒素基因信息）。该克隆的系统发育定位明显不同于经典的RT033簇，表明其进化途径不同。这个新克隆与进化枝5序列型（ST）11中的几个RTs具有共同的基因组特征，包括一个完整的致病位点（PaLoc），该位点与产毒菌株中发现的更相似，与毒性较低的经典RT033形成对比（此处原文缺失具体基因信息）。一个截短为两个开放阅读框的基因（此前未描述）的存在，需要就毒素功能进行进一步评估。我们推测，在PT RT033克隆中发现的遗传元件的独特组合可能有助于宿主嗜性以及在环境中的传播和维持。本研究构成了产毒RT033克隆的首次报告，并增加了对进化枝5序列型11的总体认识，该进化枝被认为是人畜共患病潜力最高的进化谱系。该克隆在与生猪生产单位相关的所有区室中的存在表明存在一个涉及这些动物的传播链，并有助于揭示动物和环境宿主在这种病原体流行病学中所起的作用。
