Listeria - This "killer" is a bit cold

This is the 3562nd article of Da Yi Xiao Hu

Aunt Li had repeated fever, headache, nausea, vomiting, and even unconsciousness in recent days. She was diagnosed with meningitis. After careful questioning and various examinations by the doctor, it was finally determined that she had Listeria infection. The reason was that Aunt Li drank opened milk in the refrigerator. Many people are unfamiliar with Listeria infection. Today, let's learn about it together.

1. What is Listeria?

Listeria (scientific name: Listeria monocytogenes), also known as Listeria monocytogenes, is a facultative anaerobic bacterium and the pathogen of Listeria infection. It mainly uses food as a vector and is one of the most deadly foodborne pathogens. Unlike other bacteria, Listeria is not afraid of cold and can survive in 3-45 degrees. Therefore, Listeria has another nickname called "refrigerator killer". It mainly contaminates raw milk, cheese, meat and meat products, eggs, vegetable salads, seafood, ready-to-eat foods, etc.

Listeria infection is not common in the general population, but often occurs in newborns, pregnant women, the elderly, organ transplant recipients and other immune transplant populations. It can cause neonatal sepsis, miscarriage, premature birth, meningitis, bloodstream infection, etc. It can also cause self-limited gastroenteritis with fever. If an immunocompromised person is infected with Listeria, the condition is serious, with a mortality rate of up to 33%.

2. Features

1. Wide distribution

It exists in soil, water (surface water, sewage, wastewater), plants, vegetables, etc.

2. The living environment is highly plastic

It can survive at 3-45℃ and can grow and reproduce for a long time in the refrigerator.

3. Foods with higher bacteria content include

Milk and dairy products, meat (especially beef), vegetables, salads, seafood, ice cream, etc.

3. Clinical manifestations

1. Meningitis is the most common manifestation of this disease. Adult patients often show high fever, headache, nausea, vomiting, stiff neck, coma, and increased white blood cell count, mainly granulocytes. Newborns can be infected during or after delivery, and the disease will occur 1-3 weeks after delivery. The main manifestations are refusal to eat, crying, high fever, convulsions, prominent fontanelles and meningeal irritation signs. Most patients with meningitis also have bloodstream infection, and some patients may have brain abscesses.

2. When the fetus is infected with this bacteria through the placenta, miscarriage or intrauterine fetal death may occur.

3. People with lymph node infection may suddenly develop fever, headache, sore throat, swollen lymph nodes in the neck and body, enlarged liver and spleen, increased white blood cell count, and varying degrees of mononuclear cell increase.

4. Self-limiting gastroenteritis is often manifested by fever accompanied by watery diarrhea, fatigue, myalgia and other general discomfort. It usually occurs about 24 hours after ingestion of contaminated food. The symptoms last for about 1-3 days and can gradually heal on their own. Corresponding symptoms may occur when the endocardium, liver, gallbladder, muscles and other organs are infected.

4. Diagnosis and Treatment

The diagnosis of this disease mostly relies on etiology. Listeria can be diagnosed by culturing sterile specimens obtained through blood culture, lumbar puncture, etc. The recent second-generation sequencing technology (NGS) has also played an important role in the diagnosis of some patients with negative specimen cultures. A variety of antimicrobial drugs have antibacterial effects on Listeria, but ampicillin is the first choice. Patients allergic to penicillin can choose macrolides, sulfonamides, vancomycin and other drugs according to the site of infection. Meropenem has antibiotics in vitro, but it should be noted that cephalosporin antibiotics are resistant to this bacteria. The general course of treatment is not less than 2 weeks, and the course of treatment for patients with meningitis is more than 3 weeks.

5. Prevention

Listeria can be killed after heating to 60-70℃ for 5-20 minutes, and 70% alcohol can also kill the bacteria in 5 minutes. Therefore, prevention is the main approach to dealing with Listeria: stay away from high-risk foods, such as leftovers, cheese that has not been sterilized at high temperatures, and fruits and vegetables that have been refrigerated for a long time. At the same time, develop good habits, wash your hands carefully, separate raw and cooked food, and fully heat food before eating.

Author: Emergency Department, The Second Affiliated Hospital of Xi'an Jiaotong University

Chief Physician Pei Honghong

Emergency Department, The Second Affiliated Hospital of Xi'an Jiaotong University

Written by Party Training Nurses

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