Hello! I have been a doctor for 21 years. My name is Georgy Olegovich Sapego. In this article I will tell you about bacteriophages.
Bacteriophages, or simply "phages", are a type of virus that only attacks bacteria. At the same time, they can do worse to us than our native viruses.
Phages have tails and legs, but they cannot move independently. Just go with the flow. Rather, thanks to Brownian motion.
Phages attack bacteria in two ways. In the first variant, the phage causes the bacterium to make many copies of itself. After that, the bacteria will burst, and the young phages will scatter in all directions. So they will infect more and more bacteria.
In the second variant, the phage is incorporated into the bacterial DNA and allows it to live and reproduce in peace.
At any moment, the bacteriophage can get tired of sitting quietly in the bacteria and it will detonate it like a bomb. This disgusting behavior of the phage depends on the environment and something else is not clear what.
In fact, this nasty phage behavior can be beneficial for bacteria. Yes, a bacterium can explode like a bomb, but pieces of its DNA are embedded inside the phage. Now he himself will become a carrier. This is how bacteria exchange information.
When they are friends
Phages do not attack humans. Therefore, scientists have been trying for a hundred years to adapt bacteriophages as an antibacterial agent. But somehow it's not very effective.
Bacteria are able to defend themselves against phages. And the phages themselves are not candy, and our immunity immediately tries to fight them. Therefore, they very quickly disappear from the blood.
In addition, phages are rather large objects in comparison with antibiotics. They, with their spread legs, cannot crawl into all the narrow places of our body. Because of this, phages are used primarily for topically acting drugs.
They say that it was more effective not to set phages against bacteria, but to make a medicine based on enzymes with which phages dissolve the bacterial wall. It would be a new antibiotic.
Phages can also work as spies
When tap water is checked for poop contamination, the search begins not for E. coli, but for phages that feed on E. coli.
Infected with phages, E. coli explodes, and a whole cloud of phages scatters from it. If they are swimming in water, then this is a sure sign that E.coli was also there.
That is, it is not the phages themselves that are dangerous in dirty water. They don't attack a person. It's just that phages will be a sign of poo contamination in the water.
When they are enemies
It turns out that there is little sense from phages, but they have a couple of ways to harm us.
Toxins
Oddly enough, many deadly microbes get their deadly toxins from phages. This includes the causative agents of cholera, botulism and diphtheria.
Without phages, these microbes are usually not too dangerous. It is the phages that cause bacteria to make deadly toxins. And this is not entirely clear. In the case of cholera, this would help the phages spread with diarrhea. But with botulism, a person becomes immobilized, and the phage will not be useful.
Interestingly, in the case of cholera and diphtheria, disinfection of all objects like chamber pots has to be done with the expectation of killing not only bacteria, but also all phages. And phages are usually more resistant to this chemistry than bacteria.
Horizontal gene transfer
A phage can transfer a piece of bacterial DNA to another bacterium. This is how bacteria exchange information about antibiotic resistance.
So phages are pretty bad things. If you are interested in something about this topic, then do not hesitate to ask your doctor.
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