CLOSE

Two Common Antibiotics Don’t Work the Way We Thought

The secret lives of antibiotics are more interesting than we ever knew. Researchers analyzing two commonly prescribed drugs say these medications attack bacteria using never-before-seen techniques—a discovery that could help us develop better drugs in the future. The team published its findings in the Proceedings of the National Academy of Sciences.

Chloramphenicol (CHL) is an aggressive broad-spectrum antibiotic that’s been around since the 1940s. It’s injected intravenously to treat serious infections like meningitis, cholera, plague, and anthrax, but the risks of use are so extreme that it’s typically only used as a drug of last resort.

Linezolid (LZD) is both newer and gentler. It’s prescribed for common illnesses like pneumonia and strep, but has also proven itself against drug-resistant bacteria like the one that causes the staph infection MRSA.

Despite differences in their structure, the two drugs fight disease the same way many other antibiotics do: by sticking to the catalytic center of a bacterial cell and blocking its ability to synthesize proteins. Because other drugs are universal inhibitors—that is, they prevent any and all synthesis—scientists assumed CHL and LZD would be, too.

Researchers at the University of Illinois, Chicago were not content to assume. They wanted to know for sure what the two antibiotics were up to. They cultured colonies of E. coli bacteria, exposed them to strong doses of CHL and LZD, then sequenced the beleaguered bacteria’s genes to see what was going on inside.

As expected, CHL and LZD were all up on the bacteria’s ribosomes, frustrating its attempts to put proteins together. But the drugs weren’t as totalitarian as scientists had believed. Instead, their approach seemed both specific and context-dependent, switching targets based on which amino acids were present.

"These findings indicate that the nascent protein modulates the properties of the ribosomal catalytic center and affects binding of its ligands, including antibiotics," co-author Nora Vazquez-Laslop said in a statement. In other words: It seems amino acids have a lot more influence than we realized.

As so often happens in science, finding these answers also raised a lot of questions (like "How many other antibiotics have we mischaracterized?"), but it also opens a door for medical science, said co-author Alexander Mankin.

"If you know how these inhibitors work, you can make better drugs and make them better tools for research. You can also use them more efficiently to treat human and animal diseases."

nextArticle.image_alt|e
Karen Bleier, AFP/Getty Images
arrow
Medicine
Bill and Melinda Gates Will Repay Nigeria's $76 Million Polio-Fighting Loan
Karen Bleier, AFP/Getty Images
Karen Bleier, AFP/Getty Images

Not long after announcing a $100 million donation to find a cure for Alzheimer's disease, Bill and Melinda Gates have agreed to pay off Japan's $76 million loan to Nigeria to stamp out polio, Quartz reports.

Polio has been eradicated in most countries around the world, but it's still present in Nigeria, as well as in Afghanistan and Pakistan. In 2008, according to The Conversation, Nigeria accounted for 86 percent of all polio cases in Africa. This high number was thanks in part to low immunization rates and calls from extremists to boycott polio vaccinations out of fear that they were tainted with anti-fertility steroids.

National and international campaigns were launched to lower polio rates in Nigeria, and in 2014 the nation received the loan from Japan to boost disease-fighting efforts. Progress has been made since then, with no new cases of polio reported in Nigeria in 2017. Two children had contracted polio in 2016, two years after Nigeria's last known case.

Nigeria's loan repayments to Japan were slated to begin in 2018. The Bill & Melinda Gates Foundation agreed to cover the costs after Nigeria met its goal of "achieving more than 80 percent vaccination coverage in at least one round each year in very high risk areas across 80 percent of the country's local government areas," Quartz reports. The loan will be repaid over the next 20 years.

While the Gates Foundation is lending a hand to Nigeria, the Associated Press reports that health officials in Pakistan's eastern Punjab province recently launched a new chapter in the nation's ongoing struggle against the disease. Health workers will engage in a week-long, door-to-door vaccination campaign, though efforts like this are risky due to threats from the Taliban and other militant groups, who view vaccinations as a Western conspiracy and believe they sterilize children. Anti-polio efforts in Pakistan also suffered after the CIA used vaccinations as a cover to get DNA samples from the Bin Laden compound.

[h/t Quartz]

nextArticle.image_alt|e
George Mayerle, U.S. National Library of Medicine // Public Domain
arrow
Design
This 1907 Vision Test Was Designed for People of All Nationalities
George Mayerle, U.S. National Library of Medicine // Public Domain
George Mayerle, U.S. National Library of Medicine // Public Domain

At the turn of the 20th century, San Francisco was a diverse place. In fact, Angel Island Immigration Station, located on an island in the San Francisco Bay, was known as the “Ellis Island of the West,” processing some 300,000 people coming to the U.S. in the early 1900s. George Mayerle, a German optometrist working in the city at the time, encountered this diversity of languages and cultures every day in his practice. So in the 1890s, Mayerle created what was billed as “the only [eye] chart published that can be used by people of any nationality,” as The Public Domain Review alerts us.

Anticipating the difficulty immigrants, like those from China or Russia, would face when trying to read a vision test made solely with Roman letters for English-speaking readers, he designed a test that included multiple scripts. For his patients that were illiterate, he included symbols. It features two different styles of Roman scripts for English-speaking and European readers, and characters in Cyrillic, Hebrew, Japanese, and Chinese scripts as well as drawings of dogs, cats, and eyes designed to test the vision of children and others who couldn't read.

The chart, published in 1907 and measuring 22 inches by 28 inches, was double-sided, featuring black text on a white background on one side and white text on a black background on the other. According to Stephen P. Rice, an American studies professor at Ramapo College of New Jersey, there are other facets of the chart designed to test for a wide range of vision issues, including astigmatism and color vision.

As he explains in the 2012 history of the National Library of Medicine’s collections, Hidden Treasure [PDF], the worldly angle was partly a marketing strategy on Mayerle’s part. (He told fellow optometrists that the design “makes a good impression and convinces the patient of your professional expertness.”)

But that doesn’t make it a less valuable historical object. As Rice writes, “the ‘international’ chart is an artifact of an immigrant nation—produced by a German optician in a polyglot city where West met East (and which was then undergoing massive rebuilding after the 1906 earthquake)—and of a globalizing economy.”

These days, you probably won’t find a doctor who still uses Mayerle’s chart. But some century-old vision tests are still in use today. Shinobu Ishihara’s design for a visual test for colorblindness—those familiar circles filled with colored dots that form numbers in the center—were first sold internationally in 1917, and they remain the most popular way to identify deficiencies in color vision.

[h/t The Public Domain Review]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios