Nearly one million people die every year from bacterial infections that cannot be treated with common antibiotics. This is frightening because right now we don’t have any alternatives to these antibiotics.
Antibiotic resistance occurs when bacteria change in a way that prevents the antibiotic from working. Changes in bacteria, known as resistance mechanisms, come in different forms and can be shared between different bacteria, spreading the problem.
Antibiotic resistance risks returning us to an age where even simple cuts and scrapes can become deadly. For a glimpse of what could be commonplace in our future, here are five of the scariest antibiotic-resistant bacteria from the past five years.
1. Extensively drug-resistant Salmonella typhi
This highly contagious bacterium causes typhoid fever, a life-threatening infection that affects about 21 million people around the world every year. About 1 per cent of those affected, or 223,000 people, will die.
In November 2016, a strain of Salmonella typhi emerged in Pakistan. It was resistant to five antibiotics, leaving only one oral antibiotic (azithromycin) able to treat it. Since then there have been 858 reported cases of this infection, resulting in four deaths in just one Pakistani province.
Worryingly, this strain of Salmonella typhi had changed from being multidrug-resistant (resistant to at least three classes of antibiotic) to extensively drug-resistant (resistant to all but two classes of antibiotic) in a single step. It achieved this by acquiring a piece of DNA, called a plasmid, which already contained all the new resistance genes it needed.
Even more concerning is that this strain is now only one step away from being untreatable with all available antibiotics by finding another plasmid with the resistance genes for the last two classes of antibiotic that can kill it.