Listeriosis refers to zoonotic infectious diseases, has a polymorphic clinical course with a predominance of lesions of mononuclears and nerve cells, or occurring in an anginal-septic form. Listeriosis has mainly a fecal-oral method of distribution, listeria can also enter the body by aerosol and transplacental route. According to the predominant clinical symptoms, listeriosis is divided into anginal-septic, septic-granulomatous, ocular-glandular and mixed forms. The diagnosis of listeriosis is based on the determination of monocytosis as well as the isolation of the pathogen during a bacteriological study.
ICD 10
A32 Listeriosis
General information
Listeriosis is caused by the bacterium Listeria monocytogenes, which is a motile, facultatively anaerobic, gram-positive, short rod. Listeria does not form spores, can penetrate into cells and form a capsule, contributing to the latent course of infection. They are stable in the external environment, easily tolerate freezing, multiply in soil and water, on plants and in animal corpses at temperatures from 4-6 ° C. Inactivation when exposed to sunlight occurs after 2-15 days, in formalin solution – after 20 minutes. In salted products, it can remain viable at a salt concentration of 6-20% for a long time. After 5-10 minutes, they die at a temperature of 100 ° C. Most strains, with rare exceptions, are sensitive to broad-spectrum antibiotics.
The reservoir and source of listeriosis are animals and environmental objects (water, soil, etc.). Many domestic animals and birds get listeriosis, there are cases of infection in wild mammals (rodents, foxes, minks, raccoons, ungulates) and birds (pigeons). It is possible to plant bacteria in fish and seafood. The release of the pathogen occurs with feces, saliva, milk, sperm. A person can become a source of infection when implementing a vertical path of infection (from mother to child perinatal and during lactation). Maternity hospitals and newborns secrete the pathogen 10-12 days after delivery.
Listeriosis is transmitted through a variety of mechanisms (oral, transplacental, aerosol) mainly by alimentary means. Animals become infected by consuming bacteria-contaminated water and food. Epidemiological importance in maintaining the foci of infection is played by blood-sucking insects (especially ticks), which receive the pathogen from rodents and other animals and spread it among healthy individuals.
A person usually becomes infected by eating infected animal products, or by drinking contaminated water, fresh vegetables. Transmission of infection is possible during the processing of animal raw materials (wool, down, hides, etc.), while the contact path of transmission is realized through damage to the skin. In rare cases, sexual infection from person to person has been noted, as well as vertical transmission from mother to child. People have a rather low natural susceptibility to listeriosis. The disease develops mainly in people with weakened immunity, the elderly or early childhood.
Pathogenesis
Bacteria enter the body through the mucous membranes of the digestive tract, sometimes through damage to the skin. When the pathogen spreads with blood and lymph, a feverish reaction is manifested. Listeria settles in the lymph nodes and tonsils, and other organs. There is a multiplication of bacteria (at the same time there is a corresponding local inflammatory reaction). With active progression, listeriomas (necrotic nodules) form in the lymph nodes and tissues of internal organs (and in pregnant women – in the placenta). Severe listeriosis can lead to the development of sepsis.
Listeriosis symptoms
The incubation period of listeriosis can range from several days to one and a half months. The course of listeriosis can be acute, subacute, abortive, as well as chronic – recurrent. Cases of prolonged bacterial transmission without a pronounced clinical picture have been recorded. Most often listeriosis occurs in an anginous-septic form. At the same time, the main manifestations are symptoms of angina, usually catarrhal or follicular, having a course similar to streptococcal angina. This form of listeriosis has a favorable prognosis, it is cured in 5-7 days.
With the development of ulcerative-film sore throat, accompanied by fever, the disease lasts 12-14 days with a favorable course, cough and runny nose may occur, tonsils are enlarged, sharply hyperemic and covered with films. Angina is usually accompanied by regional lymphadenitis. In some cases, listeria angina (both ulcerative-membranous and follicular) can progress into sepsis (most often in adults). At the same time, there is a pronounced remitting fever, intoxication, enlargement of the liver and spleen. There may be a variety of rashes on the skin, and a white plaque on the tonsils.
The nervous form of listeriosis occurs in the form of meningitis, meningoencephalitis or brain abscess. The clinical course of these conditions in listeria lesions does not differ from that in the case of nonspecific bacterial lesions of the central nervous system (meningeal symptoms – rigidity of the occipital muscles: symptoms of Brudzinsky and Kernig, signs of encephalitis, disorders of peripheral innervation – paresis and paralysis, polyradiculoneuritis, etc.).
The rather rare ocular-glandular form of listeriosis usually develops in case of contact with a sick animal. It manifests itself in the form of conjunctivitis against the background of general symptoms (fever and intoxication) and enlarged lymph nodes (mainly cervical and parotid). When examining patients, swelling of the eyelids is noted, the eye slit is narrowed, there are complaints of visual impairment. Lymph nodes are enlarged, moderately painful on palpation. Listeriosis in this form usually lasts from a month to three.
In newborns (and fetuses with antenatal infection) listeriosis occurs in septic-granulomatous form. Listeriosis in a pregnant woman may be asymptomatic or in an erased form, remaining unrecognized. As a result, intrauterine infection of the fetus occurs. In the early stages, it usually leads to miscarriage or gross developmental abnormalities. Listeriosis in newborns is extremely difficult, there is fever reaching critical numbers, severe intoxication, vomiting, diarrhea. The skin is cyanotic, roseolous-papular rashes are noted. There are severe respiratory and cardiac arrhythmias. The spread of the purulent process to the meninges usually ends in death.
Listeriosis in infancy initially proceeds according to the type of ARVI, with hyperthermia and catarrhal symptoms, later developing into bronchopneumonia or pleurisy. In 15-20% of cases, after recovery, children retain disorders of the functioning of the central nervous system and peripheral innervation. In some cases, the infection is chronicled. The course in the chronic form is characterized by a slight severity of symptoms, patients may notice a short-term increase in body temperature, catarrhal signs, dyspepsia. In some cases, symptoms of chronic pyelonephritis are detected.
Anginous-septic listeriosis can be complicated by endocarditis. Chronic listeriosis in individuals with severe immune disorders can lead to the generalization of severe sepsis.
Diagnostics
Listeriosis is often (especially in the case of anginous-septic form) accompanied by severe monocytosis. The number of monocytes can reach 60-70% of all white blood cells. The specific diagnosis consists in conducting a bacteriological study. The pathogen is released from the blood, liquor, mucus from the nasopharynx, smear from the conjunctiva. If necessary, a lymph node biopsy, amniotic fluid (amniocentesis) or placental punctate (chorion biopsy) are taken for analysis.
Sowing is carried out in the first 7-10 days of the disease. Serological diagnostics is performed using RA, as well as RNGA, RSC in paired serums. Serological studies can give false positive results, due to the close antigenic composition with staphylococci. In the diagnosis of the nervous form of listeriosis, a neurologist’s consultation may be required, an EEG of the brain and rheoencephalography, a lumbar puncture, if an abscess is suspected, an MRI or CT scan of the brain.
Treatment
The choice of treatment tactics is carried out in accordance with the clinical norm of the disease. Tetracycline, doxycycline, and erythromycin have a good effect as etiotropic agents. The nervous form of listeriosis is usually an indication for the appointment of intravenous administration of benzylpenicillin sodium salt. The reserve drugs include clarithromycin and ciprofloxacin. The ocular-glandular form is usually treated with the use of local remedies: a drop with sulfacetamide and hydrocortisone emulsion. If necessary, detoxification therapy, antipyretics and antihistamines are prescribed. Vitamins and adaptogens are present in complex therapy.
Prognosis and prevention
In most cases, the prognosis is favorable. The deterioration of the prognosis is noted with the development of the nervous form (there may be consequences in the form of a disorder of the central nervous system and peripheral innervation, the threat of death), pregnancy (the likelihood of termination of pregnancy and congenital listeriosis of the fetus). The disease has an unfavorable prognosis in children of the first year of life, senile people and patients with immunodeficiency.
The general prevention of listeriosis includes measures of sanitary and hygienic and veterinary control over livestock farms, food industry and catering enterprises, and water sources. As a preventive measure for the spread of infection by rodents, deratization is performed. Pregnant women, for the purpose of individual prevention, are recommended to abandon animal products that have not undergone proper culinary processing (prolonged cooking at high temperature conditions), or do not have a hygiene certificate.