It's sticky and "patina"! Every family has it, and if you don't handle it well, you will get sick

Wash, wash, wash, have you washed the dishes from yesterday's dinner today?

You will definitely find that when dishes, sinks, etc. are not cleaned for a long time, a thin layer of sticky "film" will form on the surface. To be honest, this is #bacteria mother opening the door to bacteria#, and the bacteria are "home"!

Have you ever noticed that after long-term use, the inner wall of sinks, cups and other pipes will become slippery? Did you know that some bacteria can glow in the host body? Behind these phenomena, there is actually a mysterious and complex communication language between bacteria - quorum sensing.

What exactly is quorum sensing? Imagine that bacteria are like soldiers fighting alone. When their numbers are small, they are scattered and do not have much contact with each other. However, as they slowly increase in number, they begin to "talk to each other". By secreting and sensing specific signal molecules, bacteria can know how strong their "team" is. This way of "chatting on the phone" is called quorum sensing. Quorum sensing plays an important regulatory role in many life processes of microorganisms, including bioluminescence, biofilm formation, virulence factor expression, etc., which directly affects the pathogenicity and drug resistance of microorganisms.

The “superpower” of quorum sensing

Illustration provided by Xu Feng's team

Biofilm formation

Biofilms are not uncommon in our daily lives. For example, if you don't clean your sink in time, a slippery film will soon form on it. This is actually a biofilm formed by a bacterial community, and quorum sensing plays an important role in it. Biofilms are like a bunker built by bacteria, which not only allows bacteria to survive better, but also resists the invasion of detergents and antibacterial agents because drugs have difficulty penetrating this protective barrier. This is also one of the reasons why some chronic infections are difficult to treat!

Regulating virulence

When the number of bacteria is large enough, they will activate the expression of some key genes through quorum sensing and collectively release virulence factors. For example, patients with bronchiectasis are often colonized by Pseudomonas aeruginosa. When quorum sensing of Pseudomonas aeruginosa is activated, it will promote the formation of pyocyanin toxin, causing the patient's sputum to turn green. The activation of quorum sensing makes bacteria more lethal during infection, making it more difficult for our bodies to cope with the fierce attack of bacteria.

Regulating drug resistance

Recent studies have found that bacteria can also regulate their resistance to multiple antibiotics through quorum sensing mechanisms. Professor Xu Feng's team from the Department of Infectious Diseases at Zhejiang University Second Hospital has been deeply involved in the field of quorum sensing regulation of drug resistance. Recent studies have revealed that quorum sensing of Pseudomonas aeruginosa can regulate ampC expression through the RhlI/R system, thereby regulating ampicillin resistance; and found that Pseudomonas aeruginosa promotes bacterial retention through the PQS system to counteract the effects of ciprofloxacin.

How to hack quorum sensing

It seems that quorum sensing is actually a "trouble" for us! Now that we know the "secret language" of bacteria, scientists are also trying to crack it and have developed a drug called "quorum sensing inhibitor" that specifically interferes with bacterial signal communication. It's like adding interference to a walkie-talkie, making it impossible for bacteria to talk to each other, destroying their collective action ability, and thus promoting the collapse of the bacterial population.

Quorum sensing inhibitors can make bacteria that could originally form a "collective" fight each other, making it easier for antibiotics to work. Based on this, in recent years, Professor Xu Feng's team has developed a variety of new quorum sensing inhibitor composite materials for the treatment of drug-resistant bacterial infections, and has completed preclinical research.

Quorum sensing in everyday habits

In fact, group induction affects our lives all the time. Some habits may seem harmless, but they are subtly damaging our health.

01Bad oral hygiene habits

Bacteria in the mouth form dental plaque through quorum sensing, which is the culprit of tooth decay and gingivitis.

02Not washing hands properly

Pathogens are spread by touch, and quorum sensing causes bacteria to take up residence in the body, forming persistent infections.

03Wrong use of antibiotics

The misuse or misuse of antibiotics can cause bacteria to develop drug resistance through quorum sensing and gradually evolve into "superbugs."

04 Not changing or improperly handling contact lenses

Bacteria on contact lenses form biofilms through quorum sensing, increasing the risk of eye infection.

Therefore, each of us is an "antibacterial pioneer". Although quorum sensing sounds profound, we can still use some simple methods to fight it in our daily lives. For example, wash your hands and brush your teeth frequently, use antibiotics properly, and clean places where bacteria are likely to grow in a timely manner. These small habits can reduce the accumulation of bacteria and reduce the risk of drug resistance from the source.