Most wanted superbugs!
When you hear the term “superbugs”, one imagines a giant mosquito the size of a house trying to stab characters in a science fiction movie; however, “superbugs” has been adopted as a popular name to describe those highly resistant bacteria that are troublesome to treat. I’m still undecided as to whether I like the term. But what is undeniable is that these bacteria are becoming increasingly prevalent and challenging to treat. These fears were echoed earlier this year by the UK’s Chief Medical Officer who said that increasing resistance to antibiotics was one of the greatest threats to modern medicine.
Here’s a rundown on some of the “Most Wanted”.
MRSA
MRSA stand for methicillin-resistant Staphylococcus aureus. It is a bacterium that lives on our skin and up our noses. There are two types, one of which is found in hospitals and one of which is found in the community. The community-acquired MRSA was first found in injecting drug users in the US, where it continues to be a huge problem. It can cause recurrent painful boils all over the body, which often need to be lanced or drained by a surgeon, all in conjunction with antibiotic therapy. It can also lead to an aggressive pneumonia, especially in children.
The hospital-acquired strain of MRSA is less aggressive and is not associated with those nasty boils; however, it has a downside, namely that there are fewer antibiotics with which to treat it. It tends to be more of an opportunistic infection, finding vulnerable hospital patients with intravenous lines and open surgical wounds that allow it to sneak inside them, causing all sorts of mayhem.
VRE
Vancomycin-resistant enterococcus (VRE) has been an increasing problem in hospitals around the world. The bacterium itself is quite indolent but it is its resistance to a broad range of antibiotics that worries us. We believe that VRE’s emergence is a reflection of the use of so many antibiotics, both in hospitals and the community, much of which is unnecessary and inappropriate. It is also associated with people who are in constant contact with the hospital and healthcare system such as dialysis patients. While there are a few antibiotics with which to treat VRE infections, they are expensive and often have limiting side effects.
Clostridium difficile
Clostridium difficile infection (CDI) has been an increasing problem in recent years. It is a bacterium that lives in the large bowels of a percentage of us. Even then, it won’t be a problem. But the use of antibiotics (e.g. for a throat infection or a boil on the leg) in someone with C. difficile in their bowels can be a recipe for disaster. The unfortunate scenario involves antibiotics killing billions of “good bacteria” that normally colonize our bowels but leaving C. difficile intact. This dramatic imbalance in the gut allows C. difficile to multiply and produce virulent toxins that will cause diarrhoea. While diarrhoea doesn’t sound too bad, the reality is that it is often voluminous enough to lead to dehydration. In addition, a percentage of patients can perforate their large bowel, prompting emergency surgery.
Others can even die. Despite being precipitated by antibiotics, the treatment for CDI ironically is other antibiotics! In terms of prevention, there are some data now suggesting that the use of probiotics while on antibiotics might reduce the risk of developing CDI. Probiotics are products that contain “good bowel bacteria” like Lactobacillus and can often be found in yoghurts, certain drinks and in tablets found in health food stores. But talk to your doctor if you have a low immune system before taking probiotics as they can rarely cause infections themselves. The other risk factor for having C. difficile in your bowel is the use of antacid medications (e.g. omeprazole, pantoprazole, ranitidine) for the treatment of peptic ulcers or reflux. This is because the acid in our stomach is an effective barrier to bacteria and kills them before they reach our bowels.
MRO
Under the banner of Multiresistant Organisms (MRO), we can clump a group of bacteria that are known as “Gram-negative”. There are various types with all sorts of weird and wonderful acronyms such as AmpC, ESBL, CRAB, NDM and KPC. But one guarantee is that they are all very resistant to antibiotics, which means that an infection from them can be really tricky to treat. They are found all over the world but are especially prevalent in Asia and southern Europe.
Their evolution has most likely been due to more than one factor but increasing antibiotic use, often inappropriate, is a major problem. While you might assume that the antibiotic use to which I’m referring occurs only in hospitals and doctors’ surgeries, it is not simply limited to those. Antibiotics are used in agriculture and aquaculture to treat animals for infections and even to promote their growth (I bet you didn’t know that!); therefore, antibiotics and the bacteria exposed to them can be found in the food chain and water supply. So you can see how we can even come into contact with MROs by eating food contaminated with them or just by being exposed to an external environment full of them.
A terrifying prospect, and one that some clinicians have faced already, are infections with MROs where no antibiotics can be used. In other words, a person is hospitalized with a serious infection and a doctor can’t offer them anything. It’s just like returning to a time before antibiotics existed where 75% or more people with bloodstream infections would die!
Conclusion
I’d like to paint an optimistic picture here but it’s not easy to avoid an apocalyptic forecast. There are increasing types of increasingly resistant “superbugs”, spewing into this world like all the negativity from Pandora’s box. But like that mythological container, Hope remains. With regard to “superbugs”, “Hope” is in the form of antibiotic stewardship (making sure that doctors prescribe antibiotics appropriately), good hand hygiene (so we as healthcare workers minimize the spread of “superbugs” between patients) reducing the sale of over-the-counter antibiotics (a problem in Asia), regulating the use of antibiotics in aquaculture and agriculture, and finally developing new antibiotics to which these “superbugs” are susceptible. It’s a brave new world…
(The writer is an Associate Professor of Medicine at the Australian National University (ANU) and a Specialist in Infectious Diseases)
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