In the modern period, combined infections occupy an increasingly large niche in the structure of infectious pathology. In studies on this problem, various scientists, both in our country and abroad, consider such forms of the disease, which are mainly formed as a result of interspecific interaction in the human body of bacteria, viruses, viruses and bacteria. However, there is practically no information in the literature about whether it is possible to form combined forms of infections between microorganisms of the same species, but carrying different genetic information. This paper presents an analysis of the results of more than 20 years of microbiological molecular genetic monitoring of the Laboratory of Molecular Epidemiology of the Somov Institute of Epidemiology and Microbiology for the circulation of Salmonella in the regions of the Far East and Siberia. Studies have shown that one patient may have co-infection with different plasmid types of Salmonella. However, the risk of such combinations is relatively small. There is a certain pattern between the level of prevalence of certain plasmid types of Salmonella in the region and their possible combination in one patient. In addition, it was found that variants of superinfection that occur when the patient is in the hospital, due to infection with other plasmid types of Salmonella or other serovars of S. enterica, are not excluded. At the same time, in the process of repeated examinations of the patient in the hospital, it was found that salmonella may lose certain plasmids or, on the contrary, it may have new variants. The reasons for this phenomenon remain unclear.
