Viruses in the Gut Have a Genetic Way to Fight Bacteria, Potentially Helping to Deal with Superbugs

Illustration. (Photo illustration: Pexels).

JAKARTA - A number of viruses that live in the human gut are able to produce genetic variations quickly to evade bacterial defenses. This finding has the potential to help develop alternative therapies when antibiotics are no longer effective.

Euronews quoted Sunday, August 16, saying the findings came from a study published in the journal Nature Microbiology. The research was conducted by a team from Michigan State University.

The virus of concern is bacteriophage or phage, a virus that attacks bacteria without infecting human cells.

After attaching to the bacteria, the phage inserts its genetic material and uses the cell to multiply itself until the bacteria breaks apart. However, bacteria can also build defenses against phages, just as they become resistant to antibiotics.

Researchers have found that some phages have a way to fight back. They can produce offspring with different genetic variations so that the chances of some viruses escaping bacterial defenses are greater.

The team found a particular part of the phage genome that became a "hot spot" for mutations. This part allows gene changes to occur repeatedly as the virus multiplies.

"This changes our understanding of how phages evolve," said one of the study's authors, Chris Waters of Michigan State University, as quoted by Euronews.

According to Waters, phages do not always produce exactly the same copies. Genetic variations that arise make the virus population have different characteristics.

The research was conducted, among other things, on the bacteriophage T2 that infects the bacterium E. coli. The team put the bacterial defense system into E. coli in the laboratory, then exposed it to the phage.

Bacterial defense does not last long.

"Within a few hours, the phage always starts to win. We don't understand why," Waters said.

When sequencing the genomes of phages that are able to overcome bacterial defenses, researchers found repeated mutations in a gene called agt, especially in parts of the DNA that have a repetitive sequence.

This section is called the contingency locus, which is a region of DNA that is very easy to change when the DNA copying process shifts in a repeating sequence.

The changes can result in different versions of the phage. Some of them have the potential to be more able to evade bacterial defenses.

Researchers found that the region was mutating thousands of times faster than other parts of the phage genome.

A similar mechanism is also found in the T4 phage that infects E. coli. Repetitive DNA sequences are also widely found in various other phages that attack the bacterium.

This finding comes at a time when antimicrobial resistance, including resistance to antibiotics, is increasingly a concern. The term superbug is often used to refer to bacteria that are difficult to treat because they are resistant to many antibiotics.

Fagotherapy has actually been used since the 1920s to treat bacterial infections. Interest in this method then decreased after antibiotics such as penicillin were widely used.

Now, the increasing resistance to antibiotics makes phage therapy back in the spotlight.

One of the advantages is that phages can be very selective in attacking certain bacterial species or strains. In contrast, antibiotics can kill both good bacteria and disease-causing bacteria.

However, bacteria can also develop resistance to phages. Therefore, the ability of phages to produce genetic variation is considered potentially useful for making therapies more resistant to bacterial resistance.

"If we can harness this kind of evolutionary trick, we might be able to make phage therapy more effective in the face of the antibiotic resistance crisis," Waters said.

He stressed that resistance is unlikely to be completely eliminated. However, a better understanding of how bacteria defend themselves and how phages fight back is thought to help curb the problem.