The rise of the Superbug: Research suggests air pollution may contribute to antibiotic resistance

Fiona McCluskey

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New research reveals previously unconsidered sources of antibiotic resistance

Antibiotic resistance has been discovered in the smog of Beijing city, confirming that life-threatening superbugs are linked to air pollution.

Researchers at the University of Gothenburg led by Professor Joakim Larsson have examined the genetic material of 864 samples from human, animal and environmental samples. They discovered that the highest amount of antibiotic resistance was in smog samples from the Chinese capital of Beijing. The second highest amounts were found in samples taken from areas polluted by pharmaceutical manufacturing waste. Their findings have been published in the Microbiome journal.

Superbugs are formed when patients suffering from a common bug are prescribed antibiotics and develop a resistance to the treatment. Antibiotic resistance genes (ARGs) can transfer between bugs. If the bug acquires ARGs, this results in an illness that resists the antibiotic treatment, rendering the drug ineffective. These illnesses can then persist, untreated, threatening the life of the patient and spreading to other patients. Once routine, easily treated illnesses become dangerous and potentially life threatening.

Beijing is known for its’ air pollution and smog. Coal burning is thought to be the principal cause with traces of Sulphur dioxide and formaldehyde present in the air. It has been estimated that air pollution kills an average of 4000 people in China a day due to illnesses such as lung cancer and heart disease. China aims to reduce the reliance on coal burning by increasing sources of nuclear energy. They plan to derive 20% of energy from nuclear sources by 2030.

In addition to the increasing threat to public health, the spread of superbugs also results in a much higher cost of health care. Those infected require prolonged stays in hospital and more treatment with lesser used, more expensive drugs.

Antibiotic resistant illnesses are now estimated to cause 700,000 deaths a year. The World Health Organisation (WHO), reports that 480,000 new cases of multi-drug resistance tuberculosis occurred in 2014.

Digitally-colorized scanning electron microscopic (SEM) image of pink-colored, rod-shaped, multidrug-resistant Klebsiella pneumoniae bacteria - image credit: David Dorward, Ph.D.; National Institute of Allergy and Infectious Diseases (NIAID)
Digitally-colorized scanning electron microscopic (SEM) image of pink-colored, rod-shaped, multidrug-resistant Klebsiella pneumoniae bacteria – image credit: David Dorward, Ph.D.; National Institute of Allergy and Infectious Diseases (NIAID)

Malaria strains resistant to the main malaria drug treatment have been discovered in countries such as Vietnam, Myanmar, Thailand and Cambodia. Countries in the developing world have reported that up to 15% of patients starting treatment for HIV are suffering from drug resistant forms of the virus. Given the economic impact of superbugs and the resources required to combat them, their prevalence in the developing world is cause for concern.

Another aspect to Professor Larsson’s research is the range of drug resistance seen in the samples. In addition to containing the highest amount of antibiotic resistance, Beijing smog also contains the most diverse antibiotic resistance. The research team says that the carbapenem resistance genes seen in the smog, “calls for concern, given the growing global threat of carbapenem-resistant Enterobacteriaceae” (CRE).

Common Enterobaceria include Pneumonia and Salmonella. A 2010 study found that blood infections by CRE superbugs resulted in a 42% death rate in patients. The Health Service Executive (HSE) have a set of guidelines in place for suspected cases of CRE infections in Ireland. Patients are kept in isolation to prevent the spread of the infection. In October last year, the HSE closed wards and limited visitors in Tallaght hospital, due to an outbreak of CRE infection.

At a national level, the Health Products Regulatory Authority (HPRA) is tasked with preventing the spread of antibiotic resistance. A spokesperson for the HPRA said that; “Antibiotic resistance is a growing problem that poses a major threat to public health”.

One of the main ways they aim to contain the spread of superbugs is to limit the use of antibiotics wherever possibly by promoting, “prudent and responsible use”. It is important to note that this extends beyond doctors and human health and into the agricultural sector.  The HPRA spokesperson added that; “in the absence of new treatments, there is the need for a harmonized approach towards the use of antibiotics.”

The rise of antibiotic resistance has been attributed to the rise in antibiotic use seen since the 1940s. Until now, factors such as air pollution and pharmaceutical manufacturing waste pollution have not been thoroughly investigated. This latest research by Professor Larsson’s team describes how these environments could “serve as hotspots for resistance development.”

The majority of the antibiotic resistance genes (ARGs), that the team discovered in the environmental samples have not been seen in humans. This leads to their concerning conclusion that our environment may therefore hold many future threats to human health. Stricter regulation is required for pharmaceutical industry waste disposal and air pollution.

The future impact of superbugs is not hopeless. Advancements have been made to diminish the growing problem.

A research group from the University of Oklahoma led by Professor Helen Zgurskaya has released their findings on a new class of drugs that can act against antibiotic resistant infections. This research was published in the ACS Infectious Diseases journal. These new drugs work to counteract the processes the superbugs use to resist the antibiotics. In theory, when a person infected with a superbug is given these drugs in combination with antibiotics, they will be effectively treated. Professor Zgurskaya’s team have been awarded $4.5 million in funding to further advance these new experimental drugs.

An Australian team, led by Professor Carolyn A. Michael published research in Open Biology. They focused on monitoring the types and abundance of antibiotic resistance in the environment. Their strategy is to try and predict what type of antibiotic resistance will next be acquired by human superbugs. This knowledge would allow health authorities to stop using antibiotics which are about to become ineffective, thus saving lives and money.

It is clear that the practical application of research such as this must be advanced if an adequate response to the superbug threat is to be found. Previously unconsidered “hotspots” such as areas of high air pollution must now be held accountable for the rise of the superbug.

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Fiona McCluskey