Good News About Antibiotics
By Eva Briggs, M.D.
Recently I was reading my husband’s copy of “Nature,” an international science journal. I found a section with some good news about antibiotics. This is much appreciated when there is so much concern about drug-resistant infections and other consequences of antibiotic overuse.
Stories about AI are everywhere. It turns out that researchers are successfully harnessing the power of AI to design new antibiotics.
Scientists at the Massachusetts Institute of Technology used AI to fabricate new molecules with the goal of combatting methicillin-resistant “Staphylococcus aureus,” MRSA for short.
They used two different algorithms. Each algorithm modified a starting molecule (water, methane or ammonia) in a stepwise fashion. This generated a whopping 29 million possible antibiotic compounds. These were narrowed down to 90 potential drugs by choosing the molecules that would be easy to make, have low toxicity and high activity against “S. aureus.”
Ultimately one drug was found that was effective in the lab for clearing MRSA skin infections in mice. Eventually that could lead to an antibiotic useful for humans. MRSA is a common cause of abscesses and boils. It also causes more dangerous infections such as sepsis, pneumonia, endocarditis (a type of heart infection), and bone or joint infections.
Scientists in the United Kingdom decided to study the bacterium “Streptomyces coelicolor” which makes an antibiotic called methylenomycin A. This antibiotic was discovered over 60 years ago. The scientists wondered whether any of the intermediate chemical steps prior to the finished molecule would be effective antibiotics too. They prevented the final step in the synthesis of the drug, then prevented the step before that, and so on. To their surprise, the scientists discovered a compound called premethylenomycin C lactone which is 500 times as active against certain bacteria than the known final product. In the lab it is active against MRSA and is also effective against “Enterococcus faecium,” a cause of drug-resistant urinary infections.
A new antibiotic zolaflodacin (trade name Nuzolvence) to treat gonorrhea was approved in the United States in December. This is the second most common bacterial sexually transmitted infection in the United States. There are an estimated 700,000 to 1.6 million cases every year. Some strains of the causative bacterium “Neisseria gonorrheae” are now resistant to multiple antibiotics. Zolaflodacin successfully treated 90% of patients with gonorrhea in an experiment involving 930 patients across five counties. It is administered as a single dose taken by mouth.
Researchers in Switzerland have developed an improved test for determining whether a patient’s infection will respond to a particular antibiotic. They call the method antimicrobial single-cell testing. They can track the response of single cells in the lab and determine whether a particular drug is killing the bug or only inhibiting its growth. The hope is that this will enable doctors to select personalized treatments to effectively treat infections while decreasing the chance of creating drug-resistant bacteria.
It was refreshing to read good news about antibiotics.