Antimicrobial resistance is a natural defence system that microorganisms like bacteria, fungi, viruses and parasites develop in order to counteract the action of antimicrobial drugs. The occurrence of this extremely dangerous phenomenon has significantly increased in the last decade, making several drugs often useless, while infections once considered easily curable, can now be lethal. How serious is the situation now and what companies, here in Europe, are tackling this problem?
Antibiotic resistance surely represents one of the most dangerous threats to our health systems. More and more of these so-called superbugs are being detected all over the world. In laboratory and in hospitals, scientists and healthcare professionals witness the unsettling speed to which these multi-drug resistant bacteria are spreading around the world. Experts are currently struggling to counteract them, and no one knows how many people might already carry these superbugs.
Sounds quite alarming? Well unfortunately it is. We probably don’t know very much about this serious threat because it has not turned into a pandemic yet – specifically in western countries. But we are starting to witness the first deaths.
A few weeks ago the American Centre for Disease Control and Prevention (CDC) released a report confirming that a woman who died in Nevada in September 2016 was infected by a superbug. The infection was caused by a strain of Klebsiella pneumoniae, a bacterium that can cause urinary tract infections. This strain of pneumoniae was found resistant to all the 26 different antibiotics available in the hospital. The woman, who was in her 70s, was hospitalised in August after she had returned from a long stay in India. It is believed that the patient caught the resistant bug during this two-years period in the subcontinent, where she was repeatedly hospitalised due to her broken right femur.
The CDC emphasises that bacteria resistant to all antimicrobial are still very rare in the US and that the 90% of bacterial infections are still treatable with at least one drug. Indeed, this Klebsiella resulted susceptible to fosfomycin, an old antibiotic that, regrettably, is not licensed for such a use in US – while it is allowed in Europe. In their report, CDC also recommend that health care facilities should be allowed to obtain a patient’s history of health care exposures in order to facilitate screening for multi-drug resistant bacteria in case of recent travels in areas where the incidence of super bug is high.
And this brings us to the next point. How bad is the situation concerning antibiotic resistance in India? In 2015, an international study described for the first time the serious problem of antibiotic abuse especially in countries of growing wealth like India. There, the number of multi-drug resistant bacteria is soaring at an alarming rate, from 29% of cases in 2009 to 47% in 2014. Particularly worrying is the case of Klebsiella pmeumoniae, precisely the bacterium that killed the American woman. The number of pan-resistant Klebsiella has exploded from none in 2008 to 57 per cent in 2014.
The reason for these disquieting figures has to do with the increased use of antibiotic for curing minor infections, a way of counteracting the still low hygiene level in most of the country. Furthermore, according to experts, this spread of pan-resistant bugs is threatening especially the weakest part of the population, the newborns.
However, the misuse of antibiotics in the healthcare practice is not the worst aspect of this threat. Almost two-thirds of the antibiotics produced globally are consumed in the farm sector, where mixture of these drugs are routinely included in feed for livestock in order to fatten up pigs and chickens. This practice seems to be particularly common in China.
It is indeed in China that researchers discovered mcr-1 in November 2015. mcr-1 is a mutated gene that makes bacteria resistant to colistin, the last antibiotic for which a specific resistance gene had not been identified yet. The mcr-1 gene contains a stable mutation that can be easily transmitted to other bacteria. It took just a few weeks before the exact same mutation was identified also in Denmark. This shows how fast bacteria can travel.
Scientists are sure that this resistance gene originated from livestock, since the vast majority of the 12,000 tonnes of colistin employed in feed for livestock yearly is used in China. The 21 per cent of animal tested in this country between 2011 and 2014 contained the mcr-1 gene. It did not take long before mcr-1 began to appear in bacteria causing common blood, gut or urinary infections in humans, like Escherichia coli and Klebsiella – the bacterium that infected the American woman.
The situation regarding antibiotic resistance is indeed worrying and something needs to be done urgently. It would be very interesting to know how pharmaceutical companies are trying to tackle this problem. I am currently interviewing some European pharmaceutical companies in the attempt to shed some light on this aspect. My interview will be published on labiotech.eu and I will provide the link to the article here on lifewithscience.net, once it is online.
Header image: Colorised scanning electron micrograph of Escherichia coli, grown in culture and adhered to a cover slop. National Institute of Allergy and Infectious Diseases, National Institutes of Health via Flickr