The emerald cockroach wasp is a mother on a mission. This parasitic insect lays its eggs on cockroaches, but to minimize the risk of the host’s many microbes and pathogens to her eggs, the wasp does what many human mothers today would do. The wasp arms her babies with sanitizer before dropping them off.
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.
This winter, an Arizona ski resort, Snowbowl, will be the first to use treated sewage water, and sewage water alone, to make manmade snow. Recycling’s usually a good thing, but opponents of the plan worry about chemicals left in the snow, and an August report by a civil and environmental engineer says that the recycled water, already used for irrigation in Flagstaff green spaces, may contain antibiotic-resistant bacteria.
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.
The rise of antibiotic-resistant bacteria has got many experts predicting a future in which currently tractable diseases, like tuberculosis, became untreatable again. The popularity of modern antibiotics, ironically, is what is leading to their downfall: antibiotics in consumer products, like soaps, as well as the excessive use of antibiotics by people who have no bacterial infections, help select for strains of bacteria that don’t respond to drugs. Factory-farmed livestock, which receive tremendous doses of antibiotics in their feed, are also a likely breeding ground for resistant bacteria that could potentially infect humans.
Proponents of factory farming have scoffed at such claims [pdf], but now, scientists have provided definitive evidence that this happens: through genetic analysis, they found that a strain of MRSA, already resistant to one family of drugs, had hopped from people to farmed pigs, acquired resistance to another antibiotic being fed to the pigs, and then leapt back into humans, taking its new resistance with it. That strain, called MRSA ST398 or CC398, is now causing 1 out of 4 cases of MRSA in some regions of the Netherlands [pdf], where it arose, and it has also been found across the Atlantic in nearly half of the meat in US commerce. After this strain arose in 2004, the European Union began a ban the use of antibiotics in livestock feed. In the United States, however, where most of the antibiotics in circulation are being used in farming, no such regulation exists.
Image courtesy of wattpublishing / flickr
For the better part of a century, antibiotics have given doctors great powers to cure all sorts of bacterial infections. But due to bacteria’s nasty habit of evolving, along with widespread overuse of these drugs, disease-causing bacteria are evolving antibiotic resistance at an alarming rate, making it much harder, and at times impossible, to wipe them out. DARPA, the military’s research agency, is eyeing an innovative solution to the problem: Rather than struggling to make better antibiotics, ditch them altogether. It may be time to start killing bacteria a whole new way.
The bacterium Micavibrio aeruginosavorus (yellow), leeching
on a Pseudomonas aeruginosa bacterium (purple).
What’s the news: If bacteria had blood, the predatory microbe Micavibrio aeruginosavorus would essentially be a vampire: it subsists by hunting down other bugs, attaching to them, and sucking their life out. For the first time, researchers have sequenced the genome of this strange microorganism, which was first identified decades ago in sewage water. The sequence will help better understand the unique bacterium, which has potential to be used as a “living antibiotic” due to its ability to attack drug-resistant biofilms and its apparent fondness for dining on pathogens.
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.
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: A gene that makes bacteria resistant to up to 14 antibiotics has been discovered in bacteria in drinking water and street puddles in the Indian capital of New Delhi by a research team from the University of Cardiff in Wales. Scientists were already aware that microbes bearing this gene, which produces an enzyme called NDM-1, were infecting people in India, but it had been thought that such bacteria were mainly picked up in hospitals. This study shows that the gene, which is capable of jumping from species to species, is loose in the environment.