Naorem Romen Singh, Blom Jochen, Fekete Csaba
Department of General and Environmental Microbiology, University of Pécs, Pécs, Hungary.
Bioinformatics & Systems Biology, Justus-Liebig-Universität Gießen, Gießen, Germany.
PeerJ. 2021 Jan 13;9:e10185. doi: 10.7717/peerj.10185. eCollection 2021.
is a drug-resistant pathogen, capable of colonizing diverse ecological niches and causing a broad spectrum of infections related to a community and healthcare. In this study, we choose four methicillin-resistant (MRSA) clinical isolates from Germany and Hungary based on our previous polyphasic characterization finding. We assumed that the selected strains have a different genetic background in terms of the presence of resistance and virulence genes, prophages, plasmids, and secondary metabolite biosynthesis genes that may play a crucial role in niche adaptation and pathogenesis. To clarify these assumptions, we performed a comparative genome analysis of these strains and observed many differences in their genomic compositions. The Hungarian isolates (SA H27 and SA H32) with ST22- type IVa have fewer genes for multiple-drug resistance, virulence, and prophages reported in Germany isolates. Germany isolate, SA G6 acquires aminoglycoside () and nucleoside () resistance genes via phage transduction and may determine its pathogenic potential. The comparative genome study allowed the segregation of isolates of geographical origin and differentiation of the clinical isolates from the commensal isolates. This study suggested that Germany and Hungarian isolates are genetically diverse and showing variation among them due to the gain or loss of mobile genetic elements (MGEs). An interesting finding is the addition of SA G6 genome responsible for the drastic decline of the core/pan-genome ratio curve and causing the pan-genome to open wider. Functional characterizations revealed that isolates survival are maintained by the amino acids catabolism and favor adaptation to growing in a protein-rich medium. The dispersible and singleton genes content of genomes allows us to understand the genetic variation among the CC5 and CC22 groups. The strains with the same genetic background were clustered together, which suggests that these strains are highly alike; however, comparative genome analysis exposed that the acquisition of phage elements, and plasmids through the events of MGEs transfer contribute to differences in their phenotypic characters. This comparative genome analysis would improve the knowledge about the pathogenic strain's characterization, and responsible for clinically important phenotypic differences among the strains.
是一种耐药病原体，能够在多种生态位定殖，并引发与社区和医疗保健相关的广泛感染。在本研究中，基于我们之前的多相特征分析结果，我们从德国和匈牙利选择了四株耐甲氧西林金黄色葡萄球菌（MRSA）临床分离株。我们假设，所选菌株在耐药性和毒力基因、前噬菌体、质粒以及可能在生态位适应和发病机制中起关键作用的次级代谢物生物合成基因的存在方面具有不同的遗传背景。为了阐明这些假设，我们对这些菌株进行了比较基因组分析，并观察到它们基因组组成中的许多差异。具有ST22-IVa型的匈牙利分离株（SA H27和SA H32）在德国分离株中报道的多药耐药、毒力和前噬菌体基因较少。德国分离株SA G6通过噬菌体转导获得氨基糖苷（）和核苷（）耐药基因，并可能决定其致病潜力。比较基因组研究允许对地理来源的分离株进行分类，并区分临床分离株和共生分离株。这项研究表明，德国和匈牙利的分离株在遗传上是多样的，并且由于移动遗传元件（MGEs）的获得或丢失而表现出它们之间的差异。一个有趣的发现是SA G6基因组的加入导致核心/泛基因组比率曲线急剧下降，并使泛基因组更宽地打开。功能表征表明，分离株的存活通过氨基酸分解代谢得以维持，并且有利于在富含蛋白质的培养基中生长的适应。基因组的可分散和单例基因含量使我们能够了解CC5和CC22组之间的遗传变异。具有相同遗传背景的菌株聚集在一起，这表明这些菌株非常相似；然而，比较基因组分析表明，通过MGEs转移事件获得噬菌体元件和质粒导致了它们表型特征的差异。这种比较基因组分析将提高对致病菌株特征的认识，并解释菌株之间临床上重要的表型差异。
