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Humans vs. Superbugs: Are We Losing The Battle?

Humans vs. Superbugs: Are We Losing The Battle?

Bacteria are gaining resistance to our last-resort group of antibiotics.

Chemotherapy, dental surgery, caesarean sections, hip replacements and organ transplants. Not one of these procedures would have been deemed safe without the discovery of the first antibiotic, Penicillin, nearly 90 years ago.

The medical world has certainly advanced in leaps and bounds, transforming the dark ages of medicine into nothing but a distant memory – or has it? Antibiotic-resistant bacteria, or ‘superbugs’ as we know them, are shooting down our current lines of defence quicker than anticipated. Recent studies have shown that our last-resort group of effective antibiotics for serious infections is becoming futile as resistant bacteria are rearing their ugly heads. Experts claim we are decades behind the race against superbugs, making an entry into a post-antibiotic era evermore likely.

We are driving the superbug epidemic

Agriculture and ignorance. If we are playing the blame game then those two factors are key players in the rise of antibiotic-resistant bacteria.

Number 1: Ignorance. Antibiotics are only effective against bacterial infections, not viral infections. Taking a course of antibiotics for the flu will not benefit your health but contribute to the growing problem of antibiotic-resistant bacteria. Not only do doctors overprescribe antibiotics, but people are irresponsibly self-diagnosing and self-medicating themselves with antibiotics bought over-the-counter or through online pharmacies.

Number 2: Agriculture. Livestock put through intensive farming are vulnerable to infections, and these can spread like wildfire in such confined spaces. The solution? Add antibiotics to animal feed. Not only will this prevent infections, but also increase muscle mass and thus meat productivity. Inevitably, such a solution has a pitfall: bacteria will evolve resistance to the antibiotics, contributing to the global burden of superbugs.

From agricultural products and hospitals, the superbugs spread to the public both directly and indirectly through the water supply, and subsequently between individuals through coughing and bad hygiene.

Colistin: another victim of the war against bacteria

Colistin is one of the oldest and least used antibiotics on the market. Discovered in 1959, its toxicity to kidneys made it an unfavourable antibiotic thus limiting its use and exposure to bacteria. The lack of bacterial resistance to it turned it into one of our last-resort defences against bacteria. This certainly brought a sigh of relief when bacteria behind complex infections such as E. coli became resistant to our penultimate last line of defence, carbapenems, a few years ago.

However, the attractive price tag of colistin made it the antibiotic of first choice for farmers. It is therefore of little surprise that bacteria resistant to colistin in infected livestock, meat and humans was recently discovered. The team of Chinese researchers based at South China Agricultural University in Guangzhou who led the study, show that the gene to blame for this newfound resistance is MCR-1, and it can spread among bacteria very quickly.

Bacteria, like us, have their DNA wrapped up in structures called chromosomes. They also have DNA in another form, as circular plasmids. These structures can be easily and quickly transferred between bacteria, bringing with them whatever genes the plasmid DNA is carrying. This is how a gene that confers resistance to a drug’s toxicity spreads like wildfire between bacterial species, leading to their resistance and survival.

An even more unsettling fact of MCR compared to other forms of drug resistance such as MRSA, which works against Staphylococcus aureus, is that colistin is being pumped into millions of animals worldwide which will only quicken the spread of MCR across the globe.

As soon as the Chinese study was published, a team at the Danish Technical University in Lyngby, Denmark, searched for the MCR gene in a database of bacterial samples from animal meat and patient samples. One patient sample and samples from poultry meat imported from Germany were found to harbour this gene. The team concluded it is likely the gene traveled rather than arose independently at each location.

Taking action against the antibiotics apocalypse

Pharmaceutical companies have either reduced or stopped investing in research and development on antibiotics due to the unpredictable nature of bacterial resistance. This, as well as inappropriate use of antibiotics in healthcare and agriculture, needs to change. David Cameron, the UK Prime Minister, commissioned the Review on Anti-microbial Resistance to tackle the growing issue of drug-resistant infections. The Review team is publishing papers that cover topics such as better diagnostic tests, infection control, unlicensed internet sales, alternative treatments and the use of antibiotics in agriculture. The final report, which will include potential global solutions, will be presented to David Cameron in Spring 2016, just in time for the G20 in China.

The global disrespect for antibiotics is tragic. If these latest reports do not trigger an effective reaction then we may have to imagine a world without effective antibiotics or alternatives. I, as I am sure you too, would not like to face a future where a cut or cough could kill.

References

Liu, Y., Wang, Y., Walsh, T., Yi, L., Zhang, R., Spencer, J., Doi, Y., Tian, G., Dong, B., Huang, X., Yu, L., Gu, D., Ren, H., Chen, X., Lv, L., He, D., Zhou, H., Liang, Z., Liu, J., & Shen, J. (2015). Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: a microbiological and molecular biological study The Lancet Infectious Diseases DOI: 10.1016/S1473-3099(15)00424-7

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