Excerpt from “New Antibiotic from Soil Bacteria” by Anna Azvolinsky
That the antibiotic can kill M. tuberclosis “is a major breakthrough because it is virtually certain to be effective for the multi-resistant strains that are now all but impossible to treat,” said Richard Novick, a microbiologist at New York University Langone Medical Center who was not involved in the work.
Although further studies are needed before the antibiotic can be tested in humans, animal efficacy models are often predictive of a drug’s effects in humans, said Gerard Wright, director of the Institute for Infectious Disease Research at McMaster University in Hamilton, Canada, who penned an accompanyingeditorial.
Teixobactin was isolated from a previously unknown Gram-negative bacterium that lives in soil and cannot be cultured in the lab using standard techniques. So the researchers applied an approach called Ichip, developed jointly by Lewis and Slava Epstein’s lab, in which a soil sample is diluted with agar, and a single bacterial cell is suspended in a chamber surrounded with semi-permeable membrane. The researchers pack 96 such chambers into a single device, which they then place in soil—allowing the bacteria access to nutrients and growth factors but not to escape. This cultivation approach is an innovative way to tap into the rich biodiversity that we are currently missing because only 1 percent of microorganisms can be cultured in the lab, said Wright. “This biodiversity is also hiding a lot of chemical diversity that may include other new antibiotics.”
Antibiotic resistance is spreading faster than the introduction of new compounds into clinical practice, causing a public health crisis. Most antibiotics were produced by screening soil microorganisms, but this limited resource of cultivable bacteria was overmined by the 1960s. Synthetic approaches to produce antibiotics have been unable to replace this platform. Uncultured bacteria make up approximately 99% of all species in external environments, and are an untapped source of new antibiotics. We developed several methods to grow uncultured organisms by cultivation in situ or by using specific growth factors. Here we report a new antibiotic that we term teixobactin, discovered in a screen of uncultured bacteria. Teixobactin inhibits cell wall synthesis by binding to a highly conserved motif of lipid II (precursor of peptidoglycan) and lipid III (precursor of cell wall teichoic acid). We did not obtain any mutants of Staphylococcus aureus or Mycobacterium tuberculosis resistant to teixobactin. The properties of this compound suggest a path towards developing antibiotics that are likely to avoid development of resistance.
Sadly we are all reminded that life is all too short. We lost one of the best and brightest stars from our BMCDB galaxy. Words fail to express how much he meant, how his presence made us all better, and how much we will miss him.
I am putting this blog post up in the hopes that people will share not just their thoughts and condolences, but also their favorite memories and stories Nick. I know his influence will stay with me for a life time. I can’t think of much else to say other than to talk to those you care about, never take anyone for granted, and share the warmth, love, and compassion that he shared with all of us. RIP Nick
Dear BMCDB faculty and students,
It is with great sorrow that I share with you this sad news.
The graduate group has received word that Nick Mahoney, a third year Ph.D. candidate, working in Chris Fraser’s lab, passed away Saturday from a heart attack. There is no additional information at this time, but I wanted to let you all know of this tragic event. Our hearts go out to Nick’s family. I will keep you posted as to what arrangements are being made as I become aware of them.
Campus psychological services are also available if you find you or someone you know needs to reach out for confidential support. The Counseling Center for Psychological Services (CAPS) is available for students. Please call (530) 752-0871. The Academic & Staff Assistance Program (ASAP) is available to faculty and staff. Please call (530) 752-2727.
Our thoughts go out to his family, friends and colleagues,
Dear BMCDB students and faculty,
Sydney Mahoney has asked that you be informed of services for Nicholas Mahoney. She will have a visitation with family on Saturday, December 13th from 2:00-5:00 p.m. at Wiscombe Funeral Home. A Memorial Service will be at the Unitarian Church on Sunday Dec. 28th at 3:00 p.m.
Both services are open to faculty, students, and staff.
Erin C. Kent, Ph.D