Abe Lab
Lab of Bacterial Pathogenesis
Research Institute for Microbial Diseases
Osaka University
世界中に蔓延する抗菌薬耐性菌の増加スピードは驚異的であり、2050年には薬剤耐性菌による死者数が悪性腫瘍による死者数を上回る可能性も示唆されています。抗菌薬の使用自体が抗菌薬耐性を生み出す直接的な原因であることは疑いようがありませんが、現在の臨床現場においては細菌感染を適切に診断し、適切に抗菌薬を使用することは実はまだ容易ではありません。私たちは病原細菌とそれに対する宿主免疫、さらには抗菌薬の相互関係について解析し、より良い診断法や治療指針の提案に寄与できることを目指しています。
Worldwide rapid dissemination of antimicrobial-resistance (AMR) is staggering, and the number of deaths associated with AMR is estimated to exceed that of deaths due to cancers in the near future unless global response is mounted. There is no doubt that antimicrobial use itself is a direct cause of antimicrobial resistance, but it is still challenging to diagnose bacterial infections and use antimicrobials appropriately in current clinical settings. Our goal is to contribute to better diagnostics and treatment guidelines by revealing the interrelationships among pathogens, host immunity, and antimicrobial agents.
細菌性の血流感染は細菌と宿主免疫間の複雑な相互反応の結果生じており、細菌と宿主免疫の組み合わせ次第で多彩な転機を辿ります。例えば、健常人においても常在フローラ中の細菌が機に乗じて血流に入り込んでいることが知られていますが、これらの侵入細菌は瞬時に自然免疫系によって排除・殺菌されるため、通常は病原性を発揮することはありません。ところが、細菌側因子と宿主側因子の個体差次第では、致死率の高い血流感染症を引き起こす可能性もあるのです。細胞性免疫が作動する前段階に病原体と液性免疫がどのように関わるのか、また病原菌及び宿主液性免疫の個体差が生じる要因やその臨床上の影響について研究します。
Inter-Individual and Strain-Specific Differences in Plasma Bactericidal Activity
Bacterial bloodstream infections result from complex interactions between bacteria and host immunity. It is known that daily asymptomatic or transient bacteremia can immediately resolve in healthy individuals without sequelae by the innate immune system. However, a dysregulated host response to the invading bacteria can cause bloodstream infections that are associated with a high mortality rate. We are studying the humoral and bacterial factors that cause such inter-individual and inter-strain heterogeneity. Additionally, we are analyzing how such factors are associated with the onset and severity of bacterial infections.
Figure
Overview of constitutive innate immune responses of humoral and cell-mediated immunity.
Diverse constitutive innate humoral immunity can directly attack pathogens through non-inflammatory mechanisms when a pathogen is detected. PAMPs can subsequently induce innate cellular immune responses via PRRs, including the production of cytokines involved in inflammation. (Abe R. et al., Lancet Infect Dis. (2023) 6:S1473-3099(23)00494-2.)
現在臨床現場では、抗菌薬を添加した人工栄養培地における菌の発育抑制効果に基づいて抗菌薬選択が行われており、宿主因子を考慮した手法は取られていません。宿主因子、病原菌、抗菌薬という3つの因子を包括した、従来とは異なる薬剤感受性試験を将来的に提示することを目標としています。
Inter-Relationships among Pathogens, Host Immunity, and Antimicrobial Agents
Currently, in clinical practice, antimicrobial susceptibility tests measure the inhibition of bacterial growth by antimicrobials in artificial nutrient media, and host factors are not evaluated. Our goal is to establish an antimicrobial susceptibility test that evaluates host factors, pathogens, and antimicrobial agents with higher resolution.
当研究室は大阪大学微生物病研究所日本タイ感染症共同研究センターの薬剤耐性菌部門と共に研究を行なっています。タイで収集されたカルバペネム耐性菌とそのゲノム解析結果を用いて、その拡散メカニズムや耐性メカニズム、病原因子について研究します。
Dissemination of Carbapenem Resistance in Thailand
Our laboratory is conducting collaborative research with the Section of Bacterial Drug Resistance Research of the Japan-Thailand Research Collaboration Center on Emerging and Re-Emerging Infections. Using carbapenem-resistant bacteria collected in Thailand (>2000 isolates), and genome sequencing data of all the isolates, the mechanisms of dissemination, virulence, and enhanced resistance are investigated.
Figure
Carbapenem resistance transmission in a bacterial community
(Abe R, et al., mSystems. (2023) 8:e0127522.)