Moselio (Elio) Schaechter, Distinguished Professor Emeritus at Tufts University School of Medicine, and past president of the American Society for Microbiology (ASM), died August 14, 2025, at the age of 97. 

Schaechter was a microbiologist’s microbiologist. He did groundbreaking science, was a dedicated teacher, a distinguished academic leader, an author of books that shaped the field of microbiology and an inimitable scientific communicator. In addition to his scientific influence, he was generous with his time and attention to colleagues and students, leaving him with countless collaborators and friends throughout the microbiology community.    

Schaechter was born in 1928 in Milan, Italy. As antisemitism swept across Italy, his family migrated to Quito, Ecuador. Arriving in Ecuador when he was 12 years old, Schaechter did his early schooling there. Like many future microbiologists of that era, Schaechter was lured by the excitement of microbiology after reading Paul de Kruif’s Microbe Hunters. He subsequently took a job at an Ecuadorian pharmaceutical company, where he gained hands-on microbiology experience. His interest in microbiology led him to move to the United States, where he earned an M.A. in bacteriology from the University of Kansas in 1952 and a Ph.D. from the University of Pennsylvania in 1954. [His full memoirs are available online and are engaging reading: Elio Schaechter's Memoir].

Soon after completing his Ph.D., Schaechter was drafted into the Army during the Korean War. Because of his scientific training, he was assigned to the Walter Reed Army Institute of Research. Given the importance of scrub typhus and other rickettsial diseases in the Asia-Pacific region, Schaechter was tasked with determining if Rickettsia are bacteria. After painstaking hours peering through the microscope, he demonstrated that Rickettsia reproduce by binary fission, a defining feature of bacteria. This insight was critical for developing effective treatments for Rickettsial diseases. 

After his Army service, Schaechter did postdoctoral work with Ole Maaløe in Copenhagen, yielding foundational insights into the physiology of bacterial growth and division. Over 30 years later, Stephen Cooper argued that their resulting publications gave “birth to a new field of microbiology, and have enduring importance that qualifies them for inclusion in the canon of great microbiological literature.” Schaechter's research continued to focus on the regulation of bacterial growth and division after he moved from Copenhagen to his first faculty position at the University of Florida in 1958, and when he subsequently moved to Tufts University in 1962. 

In addition to his research accomplishments, Schaechter made many other enduring contributions to science—as an exemplary university leader, teacher and scientific communicator. 

In 1971, Schaechter became Chair of the Tufts Microbiology Department. Although most chairs serve about 5 years, he held the role for more than 2 decades. He facilitated the hiring of many outstanding faculty and nurtured a culture of mutual respect and collaboration, turning it into one of the premier microbiology departments in the country. Although Schaechter turned over the chair position in 1993, the department continues to retain this participative, supportive culture.

Widely recognized for his scientific and leadership accomplishments, Schaechter was elected President of the American Society for Microbiology (ASM) in 1986, and later served in many other roles in the society. Based upon his global experiences, Schaechter was a strong believer that ASM should promote international membership. While ASM President he started a Latin America professor program to promote exchange faculty with Latin America. In 2007, ASM established the “Moselio Schaechter Award in Recognition of a Developing-Country Microbiologist” to honor exemplary microbiologists from developing countries, reflecting his belief in a truly global society.

Teaching was always a source of pride for Schaechter. He emphasized that the goal of teaching was not simply to transmit information, but to help students learn—an approach that won him many teaching awards. He continued teaching after retirement, co-founding an innovation, problem-based course for graduate students from both the University of California, San Diego and San Diego State University, and he co-taught for many years with Joe Pogliano.

When Schaechter noticed there was a microbiology topic that he thought was poorly taught, he would write a book about it. His many books have influenced students around the world. For example, when he started teaching medical school students about infectious disease, the curriculum was focused on memorizing the characteristics of a parade of pathogens. For students to be able to apply their knowledge as physicians, Schaechter thought they needed to recognize the symptoms and apply their knowledge to figure out what may have caused the disease. So, Schaechter engaged coauthors to write a new kind of textbook focused on case studies that emphasized how to diagnose infections. That textbook was first published in 1989, and new editions continue to this day as Schaechter’s Mechanisms of Microbial Disease.

Likewise, later in his career Schaechter became frustrated with general microbiology textbooks that focused on memorization of details, neglecting broader principles that integrated different aspects of microbiology. To address this issue, Schaechter recruited colleagues to write Microbe, a “new” type of microbiology textbook that emphasizes concepts instead of burying students in facts. Like his medical microbiology textbook, he turned Microbe over to authors who shared this teaching philosophy, and the book is now in its third edition.

Schaechter also wrote many other books on microbiology that serve as valuable resources for researchers and students. Several of his early books were focused on bacterial growth, often with 2 other former ASM Presidents as co-authors, John Ingraham (ASM President 1993) and Frederick Neidhardt (ASM President 1982). Also, together with additional colleagues, Schaechter co-authored the highly impactful volume Escherichia coli and Salmonella typhimurium: Cellular and Molecular Biology that aggregated important insights into bacterial growth, physiology, cell biology, genetics and molecular biology. By integrating different aspects of bacterial cell biology, physiology, genetics and molecular biology into a format easily accessible to scientists with different expertise, this book catalyzed advances in microbiology that crossed siloed subdisciplines of microbiology, such as molecular genetics and pathogenesis, as well as new fields, like synthetic biology. After a second print edition of this book it was published as an online resource, and subsequently evolved into the online resource EcoSal, continuing to provide valuable insights to students and researchers. 

As evident from his skills in teaching and writing impactful books, Schaechter was an exquisite scientific communicator. Soon after he retired from Tufts University in 1995 and moved to San Diego, California, he recognized that the microbiology community in the region was scattered, limiting communication and collaboration. To alleviate this problem, Schaechter and Doug Bartlett started the San Diego Microbiology Meetings, and these monthly meetings continue to bring together microbiologists from universities across Southern California. 

In 2006, ASM media personnel Chris Condayan proposed that ASM develop a blog focused on the amazing versatility of microbes. Schaechter quickly jumped onboard and served as Blogmaster for “Small Things Considered” for many years. In addition to interesting microbiology stories, Schaechter regularly posed “Talmudic Questions” that prompted the audience to think! Although he personally wrote many engaging blogs on a wide variety of microbiology topics, like Tom Sawyer, he enlisted others to contribute as well. Led by a new team, the “Small Things Considered” blog continues to this day, providing interesting microbiology lessons to a large audience of microbiologists and students from around the world.  
 

Another ASM communications effort developed shortly afterward was the “This Week in Microbiology” podcast. Vincent Racaniello became the host of this podcast, and promptly enlisted Schaechter as a co-host for episodes 10-253. Catalyzed by spirited discussions between the co-hosts, the podcast quickly developed a large audience that includes both scientists and non-scientists. 

As new scientific approaches are developed and new discoveries are made, it is critical that research and teaching co-evolve with the continual changes in science. Although many scientists focus on their particular interests without stepping back and considering the big picture, Schaechter led efforts to think about the future of microbiology. For example, at a time of major changes in the field, he co-authored an article in 2001 titled “The View from Here,” led a 2003 Colloquium for the American Academy of Microbiology with Roberto Kolter and Merry Buckley on “Microbiology in the 21st Century:  Where Are We and Where Are We Going?,” and co-authored a 2006 article with Stanley Maloy on “The Era of Microbiology:  A Golden Phoenix.” Each of these publications examined “what we knew” and important things we still didn’t know about microbiology, emphasizing the exciting future of the field.

Schaechter taught us that microbiology is not only about discovery and critical thinking, but about curiosity, gedanken, sharing knowledge and, at its core, people. His legacy will live on in the science he shaped, the students he inspired and the community he helped build.


Obituary written and submitted by Stanley Maloy

Further Reading:

• Moselio Schaechter’s full memoirs are available online and are engaging reading: Memoirs available at https://smallthingsconsidered.blog/.
• Cooper S. 1993. The origins and meaning of the Schaechter-Maaloe-Kjeldgaard experiments. J. Gen. Microbiol. 139: 1117-1124. DOI: 10.1099/00221287-139-6-1117.
• Schaechter M. 2015. A brief history of bacterial growth physiology. Front Microbiol. 6:  289 DOI: 10.3389/fmicb.2015.00289.
• Schaechter M. 2006. From Growth Physiology to systems biology. International Microbiol 9: 157-161.
• Schaechter M. 2016. In the Company of Microbes. ASM Books.
• Schaechter M. 1998. In the Company of Mushrooms. Harvard University Press.
• Schaechter M. 2023. The birth of the Copenhagen School:  Personal recollections at the EMBO Workshop on Bacterial Growth Physiology, 2022. Life 13: 2235 DOI: 10.3390/life13122235.