Antibiotic resistance is a well-known menace: Witness the dangers of hospital-acquired MRSA infections, or the totally drug-resistant tuberculosis found in India earlier this year. FDA statistics show that over 80 percent of antibiotics used in the US are given to livestock, and heavy animal use is thought to be one of the drivers of resistance among human pathogens. So it behooves veterinarians and public health officials alike to stamp out antibiotic resistance in animals.
In the hunt for how this resistance develops, though, scientists have been mostly looking at bacteria inside the digestive system. But it turns out they might have, er, the wrong end of things—a new study finds that drugs excreted in pee and feces may be even more worrisome than those circulating in the bloodstream.
Thanks to antibiotics, we tend to think of urinary tract infections as no big deal. Pop some cipro, and you’re done. A good thing, too—if the E. coli that usually cause UTIs crawl up the urinary tract, they can cause kidney failure and fatal blood poisoning.
But antibiotics may not be saving us from UTIs for very much longer. Scientists tracking UTIs from 2000 to 2010 found a dramatic uptick in cases caused by E. coli that do not respond to the drugs that are our first line of defense. In examining more than 12 million urine analyses from that period, they found that cases caused by E. coli resistant to ciprofloxacin grew five-fold, from 3% to 17.1% of cases. And E. coli resistant to the drug trimethoprim-sulfame-thoxazole jumped from 17.9% to 24.2%. These are two of the most commonly prescribed antibiotics used to treat UTIs. When they are not effective, doctors must turn to more toxic drugs, and the more those drugs are used, the less effective they in turn become. When those drugs stop working, doctors will be left with a drastically reduced toolkit with which to fight infection.
Shiga toxin is nasty stuff. If you are infected with a Shiga-producing bacterium, like Shigella dysenteriae or some E. coli strains, there is no clear treatment: if you are given antibiotics, your infected cells will explode, spraying the toxin all over neighboring cells and exacerbating your symptoms. Each year, 150 million people are infected with Shiga-producing bacteria, which cause dysentery and food poisoning, and a million of those die. The lack of effective treatment for such Shiga toxicosis infections is one of the main reasons this year’s outbreak of E. coli poisoning in Europe was so deadly, with more than 3,700 people infected and 45 dead. But now scientists studying how the toxin makes its way around the cell have discovered that treating mice with the metal element manganese makes them resistant to Shiga poisoning. Since manganese’s chemistry is already well understood and it’s readily available, the possibility of using it as a treatment is exciting.
Here’s how manganese blocks Shiga’s spread, according to the group’s experiments in cultured human cells:
Scientists have generally thought that superbugs are weaker than normal bacteria in drug-free environments because they expend more resources to maintain resistances, as seen by their slower cell-division rates. But researchers have now reported in the journal PLoS Genetics that some antibiotic-resistant superbugs can out-perform their normal cousins even when there are no drugs present. The results suggest that fighting these resilient bacteria will take more than just curbing antibiotic use.
The European Food Safety Authority has released a scientific report on the deadly E. coli outbreak that has sickened more than 3,500 people and killed at least 44 in the last seven weeks, and the news is grim: the apparent source of the contamination, a shipment of fenugreek seeds from Egypt, has been scattered all across the continent, making recall tricky and new outbreaks likely until the seed packets reach their expiration date in three years. Maryn McKenna of Superbug expertly breaks down the report in all its chilling detail:
What’s the News: A massive outbreak of E. coli is spreading through Europe, with 17 people dead in the last two weeks and 1,500 people sickened in Germany alone, where the outbreak began. Authorities are still trying to figure out where the outbreak originated and how it can be treated.
What’s the News: Adding sugar to certain antibiotics can boost their bacteria-battling ability, according to a study published today in Nature. In particular, sugar helps the drugs wipe out persisters, bacteria that evade antibiotics by essentially going dormant only to flare up again once the danger has passed. This technique could lead to the development of inexpensive, more effective treatments for bacterial infections.
What’s the News: Some bacteria can live in extreme “hypergravity,” found a new study published in the Proceedings of the National Academy of Sciences, surviving and reproducing in forces 400,000 times greater than what’s felt on Earth. These findings fit with the idea that microbes carried on meteorites or other debris—a ride that would have subjected them to hypergravity-strength forces—may be the ancestors of life on Earth.
Cockroaches take advantage of our messy hospitality, skulking around in the cracks and holes of our houses and devouring the scraps we leave behind. Soon, though, maybe we’ll be the ones taking advantage of their fondness for filth.
The brains of these insects carry some serious antibiotics—strong enough to slaughter bacteria that have evolved resistance to the hospital antibiotics we use. The researchers presented their work at the Society for General Microbiology meeting this week in England, and say that while the finding is terrific, it’s no surprise given the roaches’ living circumstances:
“Some of these insects live in the filthiest places ever known to man,” says Naveed Khan, coauthor of the new study. “These insects crawl on dead tissue, in sewage, in drainage areas. We thought, ‘How do they cope with all the bacteria and parasites?’” [Science News]