It’s not really a bug, and whether it’s “super” depends on your point of view. Yet superbugs have been in and out of the news fairly consistently over the last half-dozen years or so. Have you read an article about someone dying of an untreatable bacterial infection after traveling to India or an article about how we’ll soon be living in a post-antibiotic world? If yes, you’ve been reading about superbugs.
So what makes a bacterium a superbug? The definition is a bit squishy, but Mayo Clinic says it’s any bacterium resistant to the majority of commonly used current antibiotics. So, for instance vancomycin-resistant Staph aureus is a superbug, because vancomycin is the preferred drug for treating Staph infections resistant to methicillin, but MRSA (or methicillin-resistant Staph aureus) is also often considered a superbug.
Where did superbugs come from? This is still debated. Overprescription of antibiotics (such as for viral infections), patients not finishing their courses of antibiotics, and overuse of antibiotics in agriculture have all been blamed, yet there is some evidence that superbugs have always existed. For instance, superbugs have been found deep inside caves or permafrost, where they would have had little exposure to antibiotics. However, regardless of where they came from, overuse and misuse has almost certainly increased their prevalence. See, development of antibiotic resistance works as is shown below–
–that is, as antibiotics are used, they kill off everything which isn’t resistant.There’s also some evidence that bacteria which aren’t fully resistant can develop resistant if they are exposed to sublethal doses of antibiotic (1). So overuse and misuse of antibiotics certainly increase the percentage of superbugs in circulation.
What can we do about them? Well, this is where it gets tricky. For a drug to get approved by the FDA usually takes about 20 years, from first discovery to going on the market. Meanwhile, there have only been a couple of new antibiotics discovered in the last few decades. Other options, such as treating superbugs with virus specific to bacteria, are still in testing.
On the bright side, there is not much evidence that these superbugs are more stress tolerant or virulent than antibiotic-susceptible bacteria. So we can still cook them to death or kill them with disinfectants.
On the not-so-bright side, superbugs are especially prevalent in the developing world, where antibiotics are under-regulated and overprescribed, healthcare systems are weak, and the efficacy and quality of antibiotics varies wildly. Consequently, it is important that we continue to invest in international initiatives (such as with WHO) to improve healthcare and antibiotic usage.
**If there is interest in this, I will write another post on ways bacteria survive antibiotics.
Straightforward discussion: https://cosmosmagazine.com/biology/what-is-a-superbug
(1) Levin-Reisman, I., I. Ronin, et al. (2017). “Antibiotic tolerance facilitates the evolution of resistance.” Science 355(6327): 826-830.