Heterogeneity of Salmonella isolates obtained from various sources in Russia 2010–2019

Aim: the goal of the study was to evaluate the heterogeneity of the Salmonella enterica subsp. enterica strains isolated from clinical specimens and various environmental sources in the Russian Federation during the period 2011–2019.

Materials and methods. The data of 3076 non-typhoid isolates of Salmonella obtained from sporadic and outbreak cases of salmonellosis (n = 2518), food and water samples (n = 558) were used. These isolates were serotyped according to the Kaufman–White scheme and genotyped by Pulsed-Field Gel Electrophoresis (PFGE) using XbaI and BlnI restriction endonucleases according to a standard PFGE-protocol developed by PulseNet International Network.

Results. The studied Salmonella isolates were differentiated into 73 serotypes and 601 PFGE types. A comparative analysis of isolates from various sources made it possible to identify subtypes that differed significantly in their prevalence in humans and potential transmission factors (sources). A significant proportion of chicken, turkey, and pork meat samples contained PFGE-subtypes which did not occur in clinical samples. Regional differences in the heterogeneity of the Salmonella spp. were also identified.

Conclusions. Genetic heterogeneity of the Salmonella population from humans and other sources shows significant variability of virulent properties and indicates the necessity of differentiated assessment of their epidemiological potential.