Astorg, a pan European private equity firm, has signed a definitive agreement to acquire New York-listed Thermo Fisher Scientific’s microbiology business for approximately US$1.075bn, consisting of cash and a US$50m seller note.
The microbiology business provides antimicrobial susceptibility testing and culture media solutions for clinical, pharmaceutical and food safety testing. It generated US$645m in revenue in 2025. Through the transaction, Thermo Fisher’s microbiology business will become an independent, privately owned platform with approximately 2,400 employees, operating 13 manufacturing and R&D sites globally.
“This investment reflects our strong conviction in microbiology diagnostics and exemplifies Astorg’s approach to creative dealmaking, leveraging deep sector expertise to identify global assets, navigate complexity and translate it into a clear, executable growth strategy,” said Judith Charpentier, co-managing partner and head of Healthcare at Astorg.
Astorg will partner with management to scale the business’ next phase of development, focusing on accelerating organic growth, executing M&A, and further strengthening operational capabilities.
“We are excited to build the next phase,” said Olivier Lieven, partner, and Paul Arhanchiague, managing director at Astorg. “We see a wealth of opportunities for the business, across product innovation, commercial depth, and M&A.”
For Thermo Fisher, the transaction reflects: “our active management of the company and provides additional capital we can deploy to create shareholder value,” said Marc Casper, chairman and CEO. “We believe the microbiology business is an excellent fit within Astorg’s portfolio.”
Astorg was advised by Evercore and Moelis & Company (financial advisors), and Latham (legal advisor). Thermo Fisher management was advised by Perella Weinberg Partners and Wells Fargo (financial advisors) and Cravath, Swaine & Moore (legal advisor).
Press release: Astorg to Acquire Global Microbiology Business from Thermo Fisher Scientific – Astorg | Uncovering value through the art of listening
