Carbapenemase-producing Enterobacteriaceae (CPE) are bacteria that have developed resistance to carbapenems, a class of last-resort antibiotics available to hospitals, and as a result, pose a serious threat to public health. CPE is carried harmlessly in the gut, but if it enters the bloodstream through a wound of a sick or elderly patient, it can prove fatal, making it a serious danger for hospitals. Dubbed the “nightmare bacteria” by Tom Friedan, former Centers for Disease Control Prevention (CDC) head, about 40-50% of patients afflicted with a CPE bloodstream infection die.
While CPE is not totally untreatable, it’s difficult as more complicated antibiotic combinations and older, more toxic drugs have to be used. In the United Kingdom, lab-confirmed cases of the bug rose from three in 2003 to almost two thousand in 2015. The actual number may be much higher though, as hospitals are not required to report suspected cases. In the United States, the CDC estimates that CPE causes 9,300 infections and 600 deaths in hospitals each year. In December last year, researchers at the Ohio State University discovered CPE at a US swine farm. While no CPE was detected in the pigs themselves, the fact that CPE was found at all on a livestock farm is alarming.
The researchers identified the beta-lactamase gene IMP-27 on some of the samples, which confers resistance to carbapenem antibiotics. Plasmids are small rings of DNA that are easily transferred between different species of bacteria, and can contain genes, like IMP-27, that give bacteria new traits. The IMP-27 gene was found on IncQ1 plasmids. IncQ plasmids present a heightened concern, as they have the broadest host range of any known replicating element in bacteria. High levels of CPE have also been found in India, Pakistan, the Middle East, south and Central America, southeast Asia, China, Japan, parts of Europe, and more.
The introduction of penicillin in the 1940s hailed a new age for medicine; twenty other classes of antibiotics went on to be discovered in the next 42 years. However, since 1987, no new classes have been discovered, and the misuse and overuse of antibiotics have led to an explosion of antibiotic resistance. The World Health Organization predicts drug-resistant infections kill about 700,000 people around the world annually, and if new, effective antibiotics are not discovered, such infections will kill 10 million people a year by 2050.
All hope is not lost – in January of 2015, a team of scientists finally discovered a new class of antibiotics – the first being dubbed teixobactin – by conducting experiments in soil instead of artificial petri dishes. Previously, scientists kept testing the same soil samples over and over, never finding any new antibiotics, but as it turns out, 99% of microbes just do not proliferate in laboratory conditions. Now, scientists have access to virtually 100% of Earth’s microbes, meaning scores of not just new antibiotics, but also anti-cancer agents, immunosuppressives, etc., may be found in our new little friends. These new antibiotics still a long ways from being approved for human use, but are very promising.