Identification of elucidation and the molecules related in biofilm-forming of bovine quarters by Staphylococcus aureus

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K15670
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 42020:Veterinary medical science-related
• Research Institution: National Agriculture and Food Research Organization
• Principal Investigator: Nagasawa Yuya 国立研究開発法人農業・食品産業技術総合研究機構, 動物衛生研究部門, 主任研究員 (20759352)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: 牛 / 乳房炎 / 黄色ブドウ球菌 / バイオフィルム

Outline of Final Research Achievements

Staphylococcus aureus (SA) is the most common etiologic agent of chronic and intractable bovine mastitis. Biofilm formation is considered to be one cause for recurrent and persistent infections, and may be virulence factor of chronic bovine mastitis caused by SA. However, whether biofilms of SA relate to infect the bovine udder are not still well understood. The aim of this study was to investigate changes in biofilm formation ability of the same SA strain (BM1006 strain) from milk experimentally infection during serial passage. Results show that AgrA and SigB mutant were emergenced during SA infection in bovine quarters. These mutants present different ability of biofilm-forming, expression of proteins, virulence, compared with original strain. Elucidation of the mechanisms of biofilm formation by SA may lead to new preventive or treatment measures for chronic, or intractable, in dairy cows.

Free Research Field

獣医学

Academic Significance and Societal Importance of the Research Achievements

SA性乳房炎に対するバイオフィルムの研究は、病態とどのような関連性があるかなどのin vivoにおける基礎的な知見が不足しているのが現状である。本研究では、SAは牛の乳房内感染が持続するうちに、AgrAやSigBの遺伝子に変異が起き、バイオフィルム形成能などが変異する現象が起こることが示された。こうした変異が黄色ブドウ球菌性乳房炎の難治性・慢性感染の一因である可能性があり、このような変異を示す分子が牛乳房炎に対しての診断・治療法としての新たな標的分子あるいは防除法としての新規のワクチン抗原などに有用であることが示唆された。