What is Listeriosis?

Listeria monocytogenes is an acute infectious disease caused by Listeria monocytogenes [or translated into Listeria monocytogenes]. Patients often develop infections when their immune function is low, mainly in newborns, the elderly, pregnant women, and immunodeficiency patients. There are three species of Listeria, and only Listeria monocytogenes can cause human infection. More common in newborns and immunodeficiency children.

Basic Information

English name

listeriosis

Visiting department

Internal medicine, pediatrics

Multiple groups

Newborns, elderly, pregnant women and immunocompromised persons

Common causes

Listeria monocytogenes

Common symptoms

Meningeal irritation such as headache, dizziness, nausea, fever, neck stiffness, chills, fever, sore throat, myalgia, back pain, spastic abdominal pain and diarrhea, etc.

Contagious

Have

Causes of Listeriosis

Listeria monocytogenes is Gram-positive bacilli, facultative anaerobic, spore-free, 1 to 3 microns in length, with flagella and motility, growing in a variety of media, alkali and acid resistant, the most suitable The culture temperature is 35 37 , and the growth is lower than 4 . It can ferment a variety of sugars, produce acid and produce no gas, catalase positive, methyl red and VP reaction positive, in serum-containing glucopeptone water Can form mucopolysaccharide capsules, can produce hemolytic rings on blood agar plates, arranged in pairs in cerebrospinal fluid samples, shaped like cocci.

Clinical manifestations of listeriosis

The incubation period ranges from a few days to a few weeks. The most common clinical form of listeriosis is meningitis; followed by bacteremia without localized manifestations, with or without meningitis, and about 10% of central nervous system parenchymal lesions Endocarditis accounts for 5%, and other rare uveitis, endophthalmitis, cervical lymphadenitis, pneumonia, empyema, myocarditis, peritonitis, hepatitis, liver abscess, cholecystitis, etc. caused by bloodstream dissemination. Osteomyelitis and arthritis.

Meningitis (meningoencephalitis)

More common in newborns and immunocompromised adults three days after birth, diabetes, liver cirrhosis or glucocorticoid therapy, 30% have no obvious cause, onset of illness, severe headache, dizziness, nausea, fever, neck stiffness After meningeal irritation, some patients have convulsions, irritability, and disorientation. The symptoms are similar to meningitis caused by other pyogenic bacteria. Severe cases can be unconscious within 24 to 48 hours. / 4 patients have focal nerve damage, if the lesions involve the brain parenchyma, there may be encephalitis, brainstem meningitis (neuroencephalitis) and brain abscesses, there may be convulsions, hemiplegia, seizures and cerebral hernia formation, etc., some The patient had only low fever and personality changes. The course of the disease was biphasic. During the first 3 to 10 days of the disease, he had fever, headache, and vomiting. Cerebral nerve palsy, in addition, there may still be ataxia, paresis, and dull feeling. Patients without meningitis usually have normal CSF examinations, or only mild lymphocytosis and increased protein content. Most CNS patients Lesions in patients with positive blood cultures.

Sepsis

Septicemic listeriosis can be seen in adults and newborns. Adults are more common in immunosuppressed patients. Newborns are more common onset within 3 days of birth. The mothers are mostly asymptomatic carriers, and the number of children is more than the placenta during delivery. Infected, known as "granulomatous infant sepsis", this bacteria is the third most common pathogen that causes neonatal sepsis and meningitis after E. coli and group B streptococci. Blue-negative bacterial sepsis is similar, but large monocytes can be as high as 8% in the classification of white blood cells. If the patient has no lymphoma, it has a diagnostic significance and a positive blood culture can be confirmed.

3. Neonatal septic granuloma

With placental infection, children with multiple internal organs (liver, spleen, lung, kidney) and brain present with multiple abscesses and / or granulomas. Amniotic fluid is contaminated with meconium, and the patient is weak, often with conjunctivitis. Pharyngitis, red papules of the skin, frequently occur on the trunk and extremities, children may have respiratory and circulatory failure, and the mortality rate is high.

4. Pregnancy infection

Women with listeriosis account for 1/3 of pregnant women and can occur at any time during pregnancy, but are more common in the next 3 months. They may have chills, fever, sore throat, myalgia, back pain, spastic abdominal pain, and Diarrhea, no special signs, generally does not affect the fetus, severe infection can cause abortion, stillbirth, premature birth or neonatal infection.

5. Focal infection

It can be caused by local contact or bloodstream dissemination. Infective endocarditis caused by Listeria does not occur in people with low immune function, but is related to heart valve damage. Aortic valve disease accounts for 2/3, and the three tips Valve lesions account for 1/3, and there are more men over 40 years of age. Patients have new or changed heart murmurs, splenomegaly, hepatomegaly, central nervous system (CNS) and liver embolism; fever is the most common (accounting for 75%), the mortality rate of this disease is high, other focal infections can be seen in skin pustules or ulcers, suppurative conjunctivitis, acute iridocyclitis, cervical lymphadenitis, arthritis, osteomyelitis, peritonitis, cholecystitis , Urethritis, etc.

Listeriosis

Blood routine

The total number of white blood cells in patients often increased, and the neutrophils increased significantly in the classification, and the monocytes did not increase.

2. Cerebrospinal fluid routine

Meningitis patients' cerebrospinal fluid mostly appears cloudy, with a white blood cell count of (100 to 10,000) × 10 ⁶ / L, of which 2/3 are multinucleated cells, and the protein content increases by 0.5 to 3.0 g / L, while only 40% of those with reduced sugar The cerebrospinal fluid of patients without meningitis is usually normal, or there is only a slight increase in protein content and lymphocytosis.

3. Bacteriological examination

Is the key to the diagnosis of this disease.

(1) Bacterial smears were taken from purulent secretions, puncture fluid, cerebrospinal fluid, biopsy cells, fetal feces and other smears, and Gram staining was performed, but it was reported that 2/3 of patients with cerebrospinal fluid were negative.

(2) Bacterial culture In the early stage of the disease, blood, cerebrospinal fluid, bone marrow, amniotic fluid, meconium, placenta, neonatal umbilical cord stump, damaged skin or mucous membranes, and vaginal excreta of pregnant women can be isolated for pathogenic bacteria.

4. Serology

The antibody response to this bacterium is mainly an increase in immunoglobulin M (IgM) antibodies. The increasing serum titer of the two serum antibodies is helpful for diagnosis, but the serum antibody test has limited diagnostic value for this disease and is only used for epidemiological research. The main reasons are: This bacterium has common antigens with other Gram-positive bacteria such as Staphylococcus, Streptococcus, Streptococcus pneumoniae, etc., often cross-react with false positives. The sensitivity of serum antibody detection is poor. Specific antibodies in the serum of newborns and immunodeficiency patients often do not increase.

5. Molecular biology testing

In recent years, nucleic acid molecular hybridization and polymerase chain reaction (PCR) methods have been used for clinical diagnosis. The PCR method can be used to detect 1 × 10 ⁴ cfu of Listeria in 250 l of blood, which is highly sensitive.

6. Routine inspection

X-ray chest, electrocardiogram, B-ultrasound and brain CT are performed.

Listeriosis diagnosis

Diagnosis is based on etiology, clinical manifestations, and laboratory tests.

Listeriosis treatment

Antibacterial treatment is generally performed.

Ampicillin

It is the best drug of choice, it is safe for pregnant women and infants, and it can reach an effective concentration in the brain.

(1) Ampicillin is administered intravenously to meningitis patients for 3 to 4 weeks.

(2) Patients with immune dysfunction were treated with ampicillin and gentamicin.

2. Penicillin

(1) Patients with heart valve infection were treated with penicillin and tobramycin.

(2) Those who are allergic to penicillin are treated with trimethoprim combined with sulfamethoxazole and intravenously.

3. Other antibiotics

Tetracycline, chloramphenicol, erythromycin, kanamycin, sulfadiazine and the like are also effective.