What do acne and chronic back pain have in common? Well, as it turns out, more than people once thought. A group at the University of Southern Denmark have found that the same bacteria that gives people spots might be to blame for up to 40% of patients with lower back pain. What’s more, these infections can be treated with antibiotics.
Your backbone is a column of alternating vertebrae (bones) and intervertebral discs (cushions). The bones provide the strength and support, while the cushion discs allow movement and flexibility. Occasionally, thanks to a mix of age and awkward movement, the disc can bulge out from between the bones. In some cases the jelly-like goo in the disc’s centre, called the nucleus, can even ooze out – a bit like thick jam leaking out of a doughnut. If the nuclear material or the disc itself puts pressure on nerves coming in and out of the spine, it can be even more painful.
Slipping a disc is, by all accounts, excruciating, but it usually starts to heal by 6-8 weeks. However, someone can be diagnosed with chronic back pain (CBP) when the pain doesn’t subside after three months. Trouble is, this happens all too often, with an estimated 4 million people in the UK suffering from CBP at some point in their lives. The cost of CBP to the NHS is about £1 billion per annum. This doesn’t even cover lost working hours or the loss of livelihood suffered. Treatment usually focuses on relieving pain, preventing inflammation and more recently, cognitive behavioural therapy to treat the patient’s psychology, especially if the organic, physical cause of the pain is no longer obvious.
Recently, scientists in Denmark found a really important link between the bacteria responsible for acne, known as Propionibacterium acnes (P. acnes) and bad backs. The researchers found that in about half of their patients with slipped discs, the disc itself was infected, usually with P. acnes. A year later, 80% of the infected patients – compared to 43% of the uninfected patients – had dodgier bones either side of the slipped disc than 12 months before. The affected bones had developed tiny fractures and the bone marrow was replaced with serum, the liquid found in blisters.
So how did the discs get infected? Bacteria like P. acnes get into our bloodstream all the time, particularly when we brush our teeth or squeeze spots. P. acnes and other similar bacteria don’t like oxygen-rich environments and so don’t normally grow inside us. The spinal disc doesn’t have a lot of oxygen around, providing a perfect home for the bacteria. If the disc is damaged – say, after popping out from the spinal column – tiny blood vessels sprout into it, letting the bacteria move in and settle down.
There, the bacteria grow and, rather than spread anywhere else, they spit out inflammatory chemicals and acid. The acid corrodes the bone next to the disc and causes more swelling and pain around the area. This discovery is ground-breaking, since before this research it was thought that discs couldn’t get infected except in a few exceptional cases.
The Danish researchers then conducted a second study, testing whether simple antibiotics could get rid of these bacteria and therefore treat chronic lower back pain. Patients that already had the characteristic signs of bone inflammation (tiny fractures and swelling) were given a 100-day course of antibiotics. The patients were reassessed a year after the trial began. Patients treated with antibiotics reported less pain, less ‘bothersomeness’ (yes!), took fewer days off work, made fewer visits to the doctor and, crucially, their bones looked in much better nick than the patients given a placebo.
Considering the huge numbers of people who are affected by chronic back pain, and the cost of treatments like surgery versus a course of antibiotics, this discovery has been glorified as the stuff of Nobel prizes. The revelation that bacteria may be to blame for some cases of this mysteriously untreatable condition rings familiar. It has been likened to the discovery of the culprit bacteria behind stomach-ulcers, Helicobacter pylori. Like back pain today, stomach ulcers were dismissed for years to be a disease of the mind, endemic among stressed-out melodramatics or people who ate too much spicy food. (And yes, Barry Marshall did get a Nobel Prize for swallowing a Petri-dishful of H. pylori.) It would be fantastic if, instead of resorting to surgery, half a million CBP patients could be effectively cured within 100 days or less!
Unfortunately, there is a downside. Antibiotics have long been the magical cure-all, but just like fossil fuels, housing and talent on TV, we’re running out. Bacteria are becoming resistant to antibiotics faster than we can create new, effective ones. It’s an arms race and we’re losing, very quickly. What’s worse is that because of the recent negativity surrounding over-prescription, there are now restrictions on giving patients broad spectrum antibiotics. Since antibiotics can’t be used as much as they were 30 years ago, pharmaceutical companies can’t make any profit from developing new ones. And so, to further compound the problem of antibiotic resistance, there are fewer and fewer antibiotics being created every year.
In 2000 alone, UK doctors made 2.6 million prescriptions of antibiotics for acne. One study by a group in Leeds looked at the number of acne patients who were infected with P.acnes and were resistant to at least one type of anti-acne antibiotic. Between 1991 and 2000, the fraction of acne patients with antibiotic-resistant bacteria rose from about a third to more than a half.
The discovery that acne bacteria might be to blame for so many cases of debilitating back pain is hugely important. However, it also highlights how dependent we are on our dangerously dwindling supply of effective antibiotics, and how we might be wasting antibiotic effectiveness on comparatively trivial conditions such as spots.
Post by: Natasha Bray