Division of Enteric Diseases, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada.
Division of Enteric Diseases, National Microbiology Laboratory, Public Health Agency of Canada, Guelph, Ontario, Canada.
PLoS One. 2021 Apr 6;16(4):e0249079. doi: 10.1371/journal.pone.0249079. eCollection 2021.
Monophasic Salmonella 4,[5]:12:i:- are a major public health problem because they are one of the top five Salmonella serotypes isolated from clinical cases globally and because they can carry resistance to multiple antibiotics. A total of 811 Salmonella 4,[5]:12:i:- and S. Typhimurium whole genome sequences (WGS) were generated. The various genetic lesions causing the Salmonella 4,[5]:12:i:- genotype were identified and assessed with regards to their distribution in the population of 811 Salmonella 4,[5]:12:i:- and S. Typhimurium isolates, their geographical and temporal distribution, and their association with non-human sources. Several clades were identified in the population structure, and the largest two were associated almost exclusively with a short prophage insertion and insertion of a mobile element carrying loci encoding antibiotic and mercury resistance. IS26-mediated deletions and fljB point mutants appeared to spread clonally. 'Inconsistent' Salmonella 4,[5]:12:i:- isolates associated with specific, single amino acid changes in fljA and hin were found in a single clade composed of water, shellfish, and avian isolates. Inclusion of isolates from different case clusters identified previously by PFGE validated some of the clusters and invalidated others. Some wgMLST clusters of clinical isolates composed of very closely related isolates contained an isolate(s) with a different genetic lesion, suggesting continuing mobility of the implicated element responsible. Such cases may need to be left out of epidemiological investigations until sufficient numbers of isolates are included that statistical significance of association with sources is not impaired. Non-human sources were frequently found in or near clinical case clusters. Prospective surveillance and WGS of non-human sources and retrospective analysis by WGS of isolates from existing culture collections provides data critical for epidemiological investigations of food- and waterborne outbreaks.
单相肠炎沙门氏菌 4,[5]:12:i:- 是一个主要的公共卫生问题，因为它们是全球从临床病例中分离出的五大沙门氏菌血清型之一，而且它们可以携带对多种抗生素的耐药性。共生成了 811 株肠炎沙门氏菌 4,[5]:12:i:- 和鼠伤寒沙门氏菌全基因组序列（WGS）。确定了导致肠炎沙门氏菌 4,[5]:12:i:- 基因型的各种遗传损伤，并评估了它们在 811 株肠炎沙门氏菌 4,[5]:12:i:- 和鼠伤寒沙门氏菌分离株中的分布、地理和时间分布以及与非人类来源的相关性。在种群结构中确定了几个进化枝，其中最大的两个与短噬菌体插入和携带编码抗生素和汞抗性的移动元件的插入物几乎完全相关。IS26 介导的缺失和 fljB 点突变似乎呈克隆传播。在由水、贝类和禽类分离物组成的单一进化枝中发现了与 fljA 和 hin 中的特定单个氨基酸变化相关的“不一致”肠炎沙门氏菌 4,[5]:12:i:- 分离株。包括先前通过 PFGE 鉴定的不同病例群的分离株验证了一些聚类，而其他聚类则无效。由非常密切相关的分离株组成的临床分离株的一些 wgMLST 聚类包含具有不同遗传损伤的分离株，表明所涉及的元素仍在继续移动。在纳入足够数量的分离株以不损害与来源的统计学相关性之前，此类病例可能需要从流行病学调查中排除。非人类来源经常在临床病例群中或附近发现。对非人类来源的前瞻性监测和 WGS 以及对现有培养物收集的分离株进行 WGS 的回顾性分析，为食源性和水源性暴发的流行病学调查提供了关键数据。
