Hello! My name is "Xiao Jin" - the autobiography of Staphylococcus aureus

Author: Tian Jingyan The Second Affiliated Hospital of Chongqing Medical University

Reviewer: Chen Weixian, Chief Technician, The Second Affiliated Hospital of Chongqing Medical University, Vice Chairman of the Inspection Branch of Chongqing Medical Association, Vice Chairman of the Inspection Branch of Chongqing Medical Doctors Association

Hi, everyone. My name is "Xiao Jin", which is commonly known as "Staphylococcus aureus". The name comes from the fact that humans observed me arranged like bunches of grapes under a microscope.

Figure 1 Copyright image, no permission to reprint

I am a common bacterium that can cause trouble in the human body and cause various diseases, such as food poisoning, skin infections, etc. If you want to resist my "attack", you need to understand my "residential location" and "attack" characteristics, the way I enter the human body, my "weapons" that cause disease, the symptoms of human infection, and how to prevent infection from me. Next, let me quietly tell you what my "secrets" are.

1. My “Permanent Location” and “Attack” Characteristics

I am a Gram-positive bacterium that is widely present in nature and is also one of the common pathogens in hospitals and communities. First of all, the air and the human mouth and nose are all places where I like to gather, especially where there is broken skin. Secondly, I also like to live in foods with high protein content, such as milk, fish, lean beef, pork, etc. I have a strong ability to infect humans and can cause a variety of diseases. For example, if humans accidentally eat food that I live in, they may experience symptoms such as nausea, vomiting, abdominal pain, and diarrhea; after I enter human skin and lungs, I may also cause them to have skin infections, pneumonia, etc. The picture below shows what my family and I look like in the blood plate culture medium and under the microscope, just like a bunch of grapes, isn’t it "cute"?

Figure 2 Copyright image, no permission to reprint

2. How do I enter the human body?

There are many ways for humans to "provoke" me.

1. Direct or indirect contact with objects, wounds or pus containing me, etc. This is the main way.

2. Sometimes I also take the "air car", that is, the droplets produced by the coughs and sneezes of the humans who have been infected by me enter the bodies of other people.

3. Eating food contaminated by me is also one of the main ways for humans to be infected. For example, after I infect food handlers, I will take the opportunity to "sneak" into the food when they cook it, or when the food is not stored properly, I will also "sneak" into it, and then enter their bodies when humans eat it.

4. I also like to "travel" between various objects in the hospital. As long as the surgical instruments and other medical supplies are not thoroughly disinfected, I will have the opportunity to enter the bodies of human patients.

3. My disease-causing “weapon”

In fact, my own lethality is limited, but I produce a substance called enterotoxin, which is my real disease-causing "weapon". Enterotoxin is very heat-resistant, and to completely destroy it, it needs to be heated at 100 degrees Celsius for 2 hours.

4. What symptoms will humans infected by me show?

When humans are infected by me in different parts of their body, they will show different symptoms.

1. Digestive tract infection: If humans eat food that has been infected by me, they may experience adverse reactions such as nausea, vomiting, diarrhea, abdominal pain, etc. If not treated in time, they may even experience systemic symptoms such as fever, muscle aches, and weakness.

2. Skin infection: It is often manifested as redness, swelling, heat and pain of the local skin and subcutaneous tissue. Some humans may also have eczema, folliculitis, etc. In addition, I like humans with pathological changes such as skin and soft tissue damage, bleeding or ulcers, because I can easily "invade" these damaged areas. If humans are not treated in time, they may develop symptoms of cellulitis such as raised blisters, high fever and swollen surrounding lymph nodes.

3. Respiratory tract infection: When the human respiratory tract is infected by me, symptoms often appear, such as coughing, expectoration, chills, persistent high fever, coughing up blood, chest pain and dyspnea. If the infection is not controlled in time, the infectious inflammation in their bodies can easily spread to the lungs over time, thereby inducing bacterial pneumonia, bronchitis, etc. In severe cases, it may develop into sepsis, meningitis, endocarditis, etc.

5. What should I do if I infect you?

Many smart people will choose to seek medical treatment in time after experiencing the above symptoms. The doctor will determine whether the symptoms are caused by me based on the corresponding examination results, and choose appropriate antibiotics to attack me based on the location and severity of the infection.

6. How can you prevent yourself from being infected by me?

In the process of "battle of wits and courage" with me, humans have discovered that taking the following measures can prevent being infected by me with a high probability.

1. Pay attention to hygiene: clean your home, ventilate it frequently, maintain good hygiene habits, and wash your hands before and after meals. In medical environments, strictly follow disinfection and sterilization procedures to ensure that surgical instruments and other medical supplies are thoroughly disinfected. Medical staff should pay attention to personal hygiene, especially washing hands frequently after handling food, contacting patients, or performing medical activities to avoid cross infection.

2. Proper storage and intake of food: Pay attention to maintaining kitchen hygiene, keep raw and cooked food separate, and ensure that food is fresh and clean. Avoid eating expired or spoiled food, and make sure that the food you eat is cooked thoroughly. In addition, storing food in a low temperature and well-ventilated environment can effectively prevent food from being contaminated by me. In seasons with higher temperatures, food should not be refrigerated for more than 6 hours, and should be thoroughly heated and cooked before eating, which can reduce the risk of food being contaminated by me.

3. Rational use of antibiotics. Human abuse of antibiotics will increase my "tolerance" to antibiotics, and then I may mutate into a drug-resistant strain or even become a "superbug", and then no drug can "kill" me. Therefore, human doctors have always emphasized the rational use of antibiotics under their guidance.

4. Strengthen exercise and improve immunity. Maintain good living habits, do more physical exercises such as running and cycling to enhance your immunity, which can effectively resist my "attack".

The above is my “secret”. After you understand it, please don’t do it according to it, otherwise no one will be infected by me!

【References】

[1] Chinese Medical Association Expert Group on Treatment Strategies for Methicillin-Resistant Staphylococcus aureus Infections. Chinese Medical Association Infection and Antimicrobial Treatment Strategies Summit Forum: Treatment Strategies for Methicillin-Resistant Staphylococcus aureus Infections - Expert Consensus [J]. Chinese Journal of Infection and Chemotherapy, 2011, 11(6): 401-416.