Listeriosis

Etiotropic therapy for listeriosis according to the literature is more often empirical . Treatment recommendations are based on a study of the sensitivity of Listeria to in vitro antibiotics , animal experiments, and clinical experience in the treatment of small groups of patients.

L. monocytogenes is known to be sensitive. ^{[ specify ]} to a wide range of antibiotics, with the exception of new cephalosporins and fosfomycin . Listeria are sensitive to penicillin derivatives (especially aminopenicillins), most macrolides (except azithromycin and spiramycin), aminoglycosides , and tetracycline . The causative agent is sensitive to representatives of glycopeptides (vancomycin) and lipopeptides (daptomycin), oxazolidinones. There are reports that most drugs from the quinolone group have moderate activity against listeria . At the same time, some researchers report that new fluoroquinolones ( levofloxacin , moxifloxacin , etc.) were active against more than 99% of L. monocytogenes strains.

Listeria infects the central nervous system and can cause meningitis and encephalitis ^[3] . Listeriosis can be fatal ^{[3] [15] [7] [8]} . The disease is most susceptible to certain groups of people. These are pregnant women, newborns, the elderly and people with weakened immune systems.

According to the US Centers for Disease Control and Prevention in the United States, about 1,600 cases of listeriosis are recorded per year. Moreover, the number of deaths due to listeriosis is about 260 ^[16] .

Published on February 21, 2017, a study by the School of Veterinary Medicine Madison (USA) showed that listeriosis can also lead to miscarriage already in the early stages of pregnancy (first trimester) ^[17] . Previously, listeriosis was recognized only in the late stage of pregnancy (third trimester), and its effect in the early stage has not been studied.

The main method of infection with listeriosis is food. The bacterium enters the human body along with food, which, in turn, become infected during production and storage.

At the same time, faced with frequent cases of infections with listeria at a food enterprise, in most cases we still don’t know what caused the contamination. At the same time, there are a number of studies showing which zones Listeria is distributed in the production workshop.

In 1990, the British Research Institute Campden BRI conducted a study of food production for the possibility of infection with monocytogenic listeria ^[18] . About 10,000 samples were taken from various food enterprises. Speaking about the distribution of positive samples in different zones, the distribution of Listeria was as follows: 53% of the samples were taken from cleaning equipment, 28% from the gangways and 19% from the floors (Fig. 1). Listeria was practically not present on the food equipment.

Moreover, 25% of all samples taken from the ladders were positive for listeria.

A similar study, but already focused only on the dairy sphere, was conducted by the Foggia Institute (Italy) in 2012 ^[19] . 34 dairy enterprises in southern Italy were investigated. Different strains of listeria were detected at 19 enterprises (56%). Speaking about the distribution of positive samples in different zones, the distribution of listeria was as follows: 19% of the samples were taken from equipment, 69% from the ramps , 12% from the products. At the same time, monocytogenic listeria was found at 7 enterprises: 19% of positive samples were taken from equipment, 73% from traps , 8% from products (Fig. 2).

Another interesting study is a 1997 study by the Norwegian College of Veterinary Medicine. The study included 40 smoked fish factories ^[20] . Samples were taken from the final product and from the ladders. Listeria monocytogenes was found in the final product in 13 plants out of 40 (33%), and in the ladders in 25 plants out of 40 (63%). Different strains of listeria were found in the final product at 16 plants from 40 (40%), and in the ladders at 30 plants from 40 (75%) (Fig. 3).

In 2018, as a result of the epidemic in South Africa, about 1000 people fell ill and 180 people died ^[21] .

With a nervous form of the disease in 98-100% of cases, the prognosis is hopeless, treatment is successful only in the very initial stage of the disease, and with a septic form, the prognosis is cautious ^[4] .

This is a widespread disease from the group of zooanthroponoses. It is found in animals of almost all species. The most commonly affected sheep. The disease is characterized by damage to the nervous system, septic effects, abortion and mastitis. ^[4] In vivo, there is a nervous, septic, genital, mixed, subclinical and latent forms of the disease. The main one is considered nervous. Infection usually occurs by an alimentary route. The pathogenic effect of the pathogen is associated with the release of exo- and endotoxins ^[22] . The incubation period for listeriosis in animals is 7-30 days ^[4] .