Bacteriophages: The Viral Solution to Super Bacteria Infections

[헬스코리아뉴스 / 이충만] Recently, as so-called ‘super bacteria’, which are resistant to all antibiotics, have gradually spread around the world, warning lights have been turned on in a public health crisis. If bacterial infection develops severely, there are voices of concern that it may become a new threat to mankind because it can lead to death. Scientists are focusing on preparing a novel treatment strategy to solve this problem with a virus.

Bacteria are small single-celled organisms that parasitize in the external environment such as land, water, and air, as well as inside other organisms such as the human intestine or stomach. There are thousands of species, and it is safe to say that they exist everywhere in the natural world that we can imagine. Even bacteria living in radioactive waste have been reported.

Common species of bacteria are anaerobic bacteria that do not require oxygen to survive and multiply. Anaerobic bacteria tend not to cause disease, and there are only a few types of bacteria that cause disease. In general, bacteria perform useful functions, such as helping to break down food in the intestines.

However, damage to body tissues or mucous membranes can lead to disease. The body loses its defenses against bacteria, and bacteria invade normally inaccessible tissues, which is called a bacterial infection.

Bacterial infections usually occur in the esophagus, skin, and intestines, and the symptoms are mild. However, infections of the heart, lungs, nervous system, and kidneys trigger inflammation that can be life-threatening, and some, such as Helicobacter pylori, increase the risk of cancer.

The standard treatment for bacterial infections is the administration of antibiotics. Antibiotics extract antibiotics from microorganisms such as blue mold and act specifically on bacteria to inhibit proliferation and growth.

The problem is that certain bacteria naturally tend to develop resistance to antibiotics to defend themselves. Such resistance is a historical concern that has been reported since the introduction of the first antibiotic, penicillin.

These bacteria either acquire genes from other bacteria that have become resistant to the drug or develop resistance to the drug through genetic modification. Genes that establish drug resistance can be passed on to the next generation of bacteria or even to other bacterial species.

The more often antibiotics are used, the more resistant bacteria they develop. Therefore, antibiotics for treating bacterial infections have been continuously developed through generations. However, with the overuse of antibiotics around the world, so-called ‘super bacteria’ that are resistant to antibiotics are emerging.

Of course, new antibiotics could cure superbugs. However, since most antibiotics were released decades ago and prices have been reduced as soon as they go down, pharmaceutical companies are not willing to jump into development because the profits are not large compared to the effort and cost involved. Even in the US, which is notoriously the most expensive drug in the world, antibiotics cost between $10 and $72.

Recently, scientists are paying attention to bacteriophages, which are bacteria-specific viruses rather than antibiotics, as an alternative that can dispel concerns about super bacteria.

Bacteriophages are microscopic viruses much smaller than intestinal bacteria, which infect bacteria and multiply only within their cells. This virus was first discovered by British microbiologist William Twort in 1915, and two years later, in 1917, French Felix d’Herelle confirmed that bacteriophage kills bacteria.

The virus attaches to the bacteria and causes the bacteria to explode, injecting its own DNA into the bacteria in the process. When bacteria are killed, bacteriophages are released into their surroundings. Some bacteriophages do not kill bacteria when infected, but insert their genes into the bacterial DNA, which causes changes in the bacterial genome and prevents the bacteria from multiplying.

At the time, few people had noticed the potential of bacteriophages for treating bacterial infections. However, due to later antibiotics, the virus was ignored by scientists for about 100 years. Little is known about its role in human health, only that it infects and multiplies gut bacteria.

Now, with the appearance of ‘super bacteria’, the situation is rapidly entering a reversal phase. As concerns about antibiotic resistance grow, interest in therapies using bacteriophages is increasing. In particular, bacteriophage infects only bacteria instead of infecting healthy cells in the body, such as influenza, Ebola, and new Corona 19 viruses.

The virus has evolved to such an extent that it can be found anywhere on the planet where there are bacteria. Chloe James, a microbiologist at the University of Salford, UK, explains: “Bacteriophages are literally ubiquitous because they are the most abundant and diverse organisms on the planet.”

In 2010, Lilli Holst, a student at the University of KwaZulu-Natal, South Africa, discovered a new bacteriophage on the underside of a rotting branch from her parents’ farm compost bin. He named the bacteriophage ‘Muddy’.

A decade later, a British teenager developed a severe infection with multidrug-resistant bacteria after two lung transplants, at which time doctors estimated his chance of survival to be just over 1%. As a last resort, medical staff administered a genetically modified bacteriophage of a different type from the ‘Muddy’ discovered by Lily Holst.

As a result, he began to regain consciousness within a few days and was discharged in good health shortly thereafter. To date, bacteriophage therapy using ‘Muddy’ has been used to treat 12 patients with bacterial infections.

However, it is analyzed that research on therapies using bacteriophages is not yet ripe, and it will take time to commercialize them. For example, bacteriophages must be genetically modified to target and infect specific bacteria, which some are skeptical about due to the complicated manufacturing process.

In addition, the reluctance to inject the virus directly into the human body is also considered a factor holding back commercialization. “It definitely has a repulsive factor,” said microbiologist Chloe James. “But it could be a useful countermeasure against a public health crisis that is helplessly crippled by super bacteria.”

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