Guzman Prieto Ana M, van Schaik Willem, Rogers Malbert R C, Coque Teresa M, Baquero Fernando, Corander Jukka, Willems Rob J L
Department of Medical Microbiology, University Medical Center Utrecht Utrecht, Netherlands.
Hospital Universitario Ramon y Cajal, Instituto Ramón y Cajal de Investigación SanitariaMadrid, Spain; CIBER Epidemiología y Salud PúblicaMadrid, Spain; Unidad de Resistencia a Antibióticos y Virulencia Bacteriana Asociada al Consejo Superior de Investigaciones CientíficasMadrid, Spain.
Front Microbiol. 2016 May 26;7:788. doi: 10.3389/fmicb.2016.00788. eCollection 2016.
Enterococci are Gram-positive bacteria that are found in plants, soil and as commensals of the gastrointestinal tract of humans, mammals, and insects. Despite their commensal nature, they have also become globally important nosocomial pathogens. Within the genus Enterococcus, Enterococcus faecium, and Enterococcus faecalis are clinically most relevant. In this review, we will discuss how E. faecium and E. faecalis have evolved to become a globally disseminated nosocomial pathogen. E. faecium has a defined sub-population that is associated with hospitalized patients and is rarely encountered in community settings. These hospital-associated clones are characterized by the acquisition of adaptive genetic elements, including genes involved in metabolism, biofilm formation, and antibiotic resistance. In contrast to E. faecium, clones of E. faecalis isolated from hospitalized patients, including strains causing clinical infections, are not exclusively found in hospitals but are also present in healthy individuals and animals. This observation suggests that the division between commensals and hospital-adapted lineages is less clear for E. faecalis than for E. faecium. In addition, genes that are reported to be associated with virulence of E. faecalis are often not unique to clinical isolates, but are also found in strains that originate from commensal niches. As a reflection of more ancient association of E. faecalis with different hosts, these determinants Thus, they may not represent genuine virulence genes but may act as host-adaptive functions that are useful in a variety of intestinal environments. The scope of the review is to summarize recent trends in the emergence of antibiotic resistance and explore recent developments in the molecular epidemiology, population structure and mechanisms of adaptation of E. faecium and E. faecalis.
肠球菌是革兰氏阳性菌，存在于植物、土壤中，也是人类、哺乳动物和昆虫胃肠道的共生菌。尽管它们具有共生性质，但也已成为全球重要的医院病原体。在肠球菌属中，屎肠球菌和粪肠球菌在临床上最为相关。在本综述中，我们将讨论屎肠球菌和粪肠球菌如何进化成为全球传播的医院病原体。屎肠球菌有一个特定的亚群与住院患者相关，在社区环境中很少见。这些与医院相关的克隆体的特征是获得了适应性遗传元件，包括参与代谢、生物膜形成和抗生素耐药性的基因。与屎肠球菌不同，从住院患者中分离出的粪肠球菌克隆体，包括引起临床感染的菌株，并非仅存在于医院，也存在于健康个体和动物中。这一观察结果表明，与屎肠球菌相比，粪肠球菌在共生菌和适应医院环境的谱系之间的区分不那么明显。此外，据报道与粪肠球菌毒力相关的基因通常并非临床分离株所特有，在源自共生生态位的菌株中也能发现。作为粪肠球菌与不同宿主更古老关联的反映，这些决定因素 因此，它们可能并不代表真正的毒力基因，而可能作为在各种肠道环境中有用的宿主适应性功能。本综述的范围是总结抗生素耐药性出现的最新趋势，并探索屎肠球菌和粪肠球菌在分子流行病学、种群结构和适应机制方面的最新进展。
