Listeriosis is a disease caused by Listeria monocytogenes, which can be manifested by various symptoms or syndromes that vary depending on the pathogenesis, site of pathogen entry and age of the affected person.
Etiology and pathogenesis
Listeria is a gram-positive, weakly pathogenic bacterium that is able to grow at a temperature of only 4°C, which is important in the transmission of the disease and the pathogen isolation on selective feeding sites.
Listeria is most likely a resident of the soil, where it multiplies, and man and animals can be infected by contaminated food. There is also a possibility of infection through direct contact with the patient.
The front door of infection is gastrointestinal tract, but manifest disease of the tract is rare as the food has to be very contaminated with bacteria (acute diarrhea). Listeria is an intracellular parasite that is isolated from the stools of almost 30% of healthy people, it is localized in the lymphoid tissue in the intestine where it enters blood , liver or other organs where it creates microabscesses.
Pathogenesis
Infection occurs in intrauterine manner or during childbirth due to contact with genital discharge of the mother. Infected fetal placenta is a source of intrauterine infection manifested by disseminated granules or abscesses, depending on the duration of the process. These lesions vary in size from microscopic to macroscopically visible, can be found in the liver, spleen, adrenal glands, lungs, central nervous system, gastrointestinal tract etc.
Listeriosis of newborns acquired during childbirth is most commonly manifested as meningitis, after 1-2 weeks of incubation. Listeric meningitis is no different from any other purulent meningitis.
As listeria is weakly pathogens, in adults it occurs in people with a weakened immune system (diabetes, alcoholism, cirrhosis of the liver, diseases of lymphoreticular system with immunodeficiency).
The clinical picture
Incubation in experimental listeriosis is 7-30 days. If the disease is triggered before birth it may end in miscarriage, premature birth to stillborn or death of a child. If infection ensues during childbirth then meningitis manifests 1-3 weeks after birth. Meningitis is manifests itself by fontanelle tension, irritability, convulsions and coma.
In infants the disease often has septicemic form known as granulomatosis infantiseptica. It may have discrete symptoms or appear as septicemia with enlarged liver and spleen and purulent meningitis.
Acquired listeriosis in older children and adults is usually manifested as purulent meningitis or encephalitis. Meningitis starts suddenly with a headache, fever, vomiting. In severe cases consciousness disturbances, convulsions and paralysis of eye muscles can occur. CSF may be blurred and usually contains up to 1000 cells, of which half can sometimes be mononuclears, but generally neutrophils prevail.
Encephalitis (inflammation of the brain) is more common in listeriosis than other purulent meningitis and can occur in almost 20% of cases, however, it is clinically indistinguishable from encephalitis of other origin. It starts with high fever, disorders of consciousness, neurological failures (brain nerve and limb paralysis) and seizures. CSF is a clear, only slightly increased number of lymphocytes is possible.
Sepsis is characterized by a temperature of continuous or intermittent type. If fever persists localization of symptoms may occur (pneumonia, endocarditis, meningitis , etc.).
Localized forms
Glandular or anginal type is similar to infectious mononucleosis with angina, enlarged lymph nodes in the neck and an enlargement of spleen.
Ocular type – purulent conjunctivitis and swollen lymph nodes in front of the ear.
Cutaneous type – veterinarians are particularly vulnerable, most commonly occurs on the hands and forearms.
Urinary type – is manifested as an inflammation of the urinary tube (urethritis) and is transmitted through sexual contact.
Listeriosis of pregnant women – often latent, but may manifest itself as an inflammation of the kidneys, unclear febrile condition, flu, etc. Listeriosis has a tendency to chronicity, it may be latent for a long time and become activated during pregnancy.
Diagnosis
Diagnosis of listeriosis is complicated, serological diagnostic methods are inaccurate and not useful, so the only way to secure the diagnosis is to isolate the cause.
Prognosis
The prognosis is worst in granulomatosis infantiseptica (mortality is between 33 and 100%) and meningitis in immunocompromised individuals (12-43 %).
Treatment
Successful treatment depends on prompt diagnosis and start of treatment.
In therapy penicillin G iv . 30,000 IU/kg per day in six doses of ampicillin and iv.200 mg/kg daily in six doses were equally successful. Therapy is recommended combined with aminoglycosides due to the synergistic effect of gentamicin 6 mg/kg iv. Or tobramycin or 1.7 mg/kg iv.3k per day. But as aminoglycosides do not penetrate well into the cerebrospinal fluid through the affected meninges. sometimes it is necessary to apply the same drug directly into the cerebrospinal fluid (intrathecal). If the patient is allergic to penicillin, he can then be given chloramphenicol iv. and aminoglycosides intrathecally. Therapy should be carried out for 3-4 weeks more after symptoms are gone.