Elucidation of the Serratia genome diversity and emerging process of highly resistant lineage and identification of highly virulent lineages

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H03472
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 49050:Bacteriology-related
• Research Institution: Kyushu University
• Principal Investigator: Hayashi Tetsuya 九州大学, 医学研究院, 教授 (10173014)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: セラチア・マルセッセンス / セラチア属 / ゲノム解析 / 系統解析 / プラスミド / 可動性遺伝因子 / 薬剤耐性 / 病原性

Outline of Final Research Achievements

Serratia marcescens (Sma) causes various opportunistic infections, sometimes hospital outbreaks. The emergence of multidrug-resistant strains further poses serious threats to global public health. Sma is also ubiquitously found in natural environments. In this study, by a large-scale genome analysis of Sma and closely related species (Sma complex), we revealed their phylogenetic relationships and complex global population structure, comprising 14 clades. Several clades exhibited distinct genome sizes and GC contents and a negative correlation of these genomic parameters was observed in each clade, which was associated with the acquisition of mobile genetic elements. In addition, we revealed that clades 1 and 2 mostly comprised clinical or hospital environment isolates and accumulated a wide range of antimicrobial resistance genes and mutations, thus clades 1 and 2 represent hospital-adapted lineages in the Sma complex.

Free Research Field

細菌学

Academic Significance and Societal Importance of the Research Achievements

セラチアマルセッセンスは代表的な日和見感染菌の一つであり、院内感染や高度多剤耐性株の出現が問題となっているが、その多様性や、臨床株と環境株の違い、近縁菌種と関係などは不明であった。本研究によって、セラチアマルセッセンスとその近縁種（Sma complex)の中の各系統と既知菌種の関係が明らかとした点が分類学的には重要であり、臨床及び病院環境由来株が大部分を占める2系統（hospital-adapted lineage）を同定した点が臨床的には重要である。