Identification of enterotoxigenic E. coli is complex and based on the direct detection of enterotoxins or toxin production genes in chromosomal or extrachromosomal genetic structures. Pathogenic and non-pathogenic Escherichia cannot be differentiated by morphological, enzymatic, or cultural properties. E. coli can be part of the normal intestinal microbiota and represented by both non-pathogenic and pathogenic strains, making the indication and identification of enteropathogenic strains directly in the studied material or isolated E. coli isolates extremely relevant. The aim of the study is to develop an express method for indication and identification of enteropathogenic E. coli isolates using the immunofluorescence reaction.
To achieve this aim, the following tasks must be accomplished:
– Isolation of enteropathogenic E. coli isolates from epidemic and epizootic foci, followed by their identification based on morphological features, tinctorial, cultural, biochemical, antigenic, and biological properties;
– Selection of an enterotoxigenic β-hemolytic E. coli strain and preparation of vaccine preparations based on it, with study of their antigenic properties;
– Selection of donor animals, testing of their immunization schemes, obtaining immune E. coli serum, and studying its activity and specificity to surface antigens of homologous and heterologous bacterial species in the agglutination reaction;
– Preparation of highly specific E. coli globulins labeled with fluorescein isothiocyanate (FITC);
– Study of the sensitivity and diagnostic value of labeled E. coli globulins in the direct immunofluorescence reaction.
The problem of food security is not conjunctural in nature. It will exist as long as there is a state, the determining factor of whose strength and authority is maintaining an appropriate level of food security. This is confirmed by the legal provision and constant attention to food security issues in EU countries, the USA, Japan, and other developed regions of the world.
During the analysis of the microbiological state of open water bodies and water supply systems in Ukraine and Volyn region in particular for the period 2020–2024, we detected a nationwide trend toward an increase in the proportion of samples with above-norm indicators in open water bodies. Analysis of drinking water showed higher reliability of municipal water pipes compared to rural networks and wells. The obtained results indicate the need for further systematic monitoring of microbiological water indicators to stabilize the sanitary condition of water resources and reduce risks to food security and public health in general.
In the complex of problems ensuring Ukraine's food security, monitoring of livestock products for quality and safety indicators also plays an important role. Monitoring the quality and safety of agricultural products is a component of the "One Health" strategy. The main tasks of this strategy within the powers of veterinary medicine are the collection, analysis, and systematization of information on contamination of feeds and livestock products with agrochemical residues, veterinary preparations, various toxic substances, and biotic contaminants. The latter include a number of toxovars of enteropathogenic E. coli strains. Given this, the development of express methods for detection and identification of various pathogenic bioconstituents belongs to the main tasks of scientific and methodological support for monitoring the safety of animal-origin products, and therefore is a relevant topic of scientific research.
One of the promising methods for express indication and identification of toxigenic E. coli strains in environmental objects and biomaterials in terms of efficiency (speed of execution, low cost, and high specificity) is the fluorescent antibodies method, as it combines the objectivity of the microscopic method with the high specificity of immunological reactions. The sensitivity and specificity of the immunofluorescence method depend on many factors, including the antigenicity of vaccine preparations, immunization schemes, and the type of donor animals. Taking into account all the aforementioned factors, we obtained highly active species-specific labeled immune E. coli globulins for indication and identification of enteropathogenic intestinal rods by the β-hemolyticity indicator in abiotic and biotic environmental objects using the direct immunofluorescence reaction.
Laboratory tests showed high diagnostic and economic efficiency of using the direct variant of MIFA (microscopic immunofluorescence analysis) as an express method for immuno-bacteriological screening of circulating enteropathogenic E. coli in veterinary-sanitary supervision and clinical samples from sick or suspected patients with intestinal infections in humans and animals.
