In sub-Saharan Africa, two genetically distinct lineages of multi-drug resistant non-typhoidal Salmonella (NTS) serovar Typhimurium sequence type 313 (ST313) are known to cause invasive disease among people. S. Typhimurium ST313 has evolved to become more human-adapted and is commonly isolated from systemic sites (eg., blood) from febrile patients in sub-Saharan Africa. Epidemiological studies indicate that S. Typhimurium is frequently isolated from systemic sites from human patients in Brazil, however, it is currently unknown if this pathogen has also evolved to become more invasive and human-adapted in this country. Here we determined genotypic and phenotypic divergence among clinical S. Typhimurium strains isolated from systemic and non-systemic sites from human patients in Brazil. We report that a subset (8/38, 20%) of epidemiologically diverse human clinical strains of S. Typhimurium recovered from systemic sites in Brazil show significantly higher intra-macrophage survival, indicating that this subset is likely more invasive. Using the whole genome sequencing and phylogenetic approaches, we identified S. Typhimurium ST313-lineage in Brazil that is genetically and phenotypically distinct from the known African ST313-lineages. We also report the identification of S. Typhimurium ST19-lineage in Brazil that is evolving similar to ST313 lineages from Africa but is genetically and phenotypically distinct from ST19-lineage commonly associated with the gastrointestinal disease worldwide. The identification of new S. Typhimurium ST313 and ST19 lineages responsible for human illnesses in Brazil warrants further epidemiological investigations to determine the incidence and spread of a genetically divergent population of this important human pathogen.

中文翻译：

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鼠伤寒沙门氏菌ST313和ST19在遗传上是不同的谱系。

在撒哈拉以南非洲，已知两种遗传上不同的多重耐药性非伤寒沙门氏菌血清型鼠伤寒沙门氏菌序列类型313（ST313）在人类中引起侵袭性疾病。鼠伤寒沙门氏菌ST313已发展成为更适合人类的病原，通常从撒哈拉以南非洲发热患者的全身部位（例如血液）中分离出来。流行病学研究表明，鼠伤寒沙门氏菌经常从巴西人类患者的全身部位中分离出来，但是，目前尚不知道该病原体是否在该国也发展成为更具侵入性和适应人类的病原体。在这里，我们确定了从巴西人类患者的系统性和非系统性部位分离的临床鼠伤寒沙门氏菌菌株之间的基因型和表型差异。我们报告说，有一个子集（8/38，从巴西全身部位回收的鼠伤寒链球菌流行病学多样的人类临床菌株中有20％显示出明显更高的巨噬细胞内存活率，表明该亚型可能更具侵袭性。使用全基因组测序和系统发育方法，我们在巴西鉴定了鼠伤寒沙门氏菌ST313谱系，其遗传和表型与已知的非洲ST313谱系不同。我们还报告了鉴定的巴西鼠伤寒沙门氏菌ST19谱系，其进化与非洲的ST313谱系相似，但在遗传和表型上不同于通常与全世界胃肠道疾病相关的ST19谱系。新S的鉴定。