A brief account of the rules applied to the naming and epidemiologically grouping Salmonella strains when isolated from animals

Abstract

Salmonella spp., the most pathogenic genus of the family of Enterobacteriaceae for man and animals, has many of its pathogenicity determinants still unknown, although it is systematically studied for more than 100 years. This is mainly due to the slow development of methods reliably associating the molecular characteristics of strains or clonal lineages with their observed pathogenicity and epidemiology. The same has hampered the effective control of animal salmonelloses, thus prevention of human infections. However, in recent years, many new molecular methods are developed to genetically, thus also taxonomically, define Salmonella spp. and are also useful in better understanding the pathogenicity of the microorganism. A better understanding of the microbe's pathogenicity is the key to the development of effective means, such as vaccines, for controlling animal salmonelloses, regardless of animal species. However, due to their costs and limited molecular information, serotyping, the classical method for many decades of placing Salmonella isolates into similar antigenic groups, remains the tool for epidemiologically studying the microorganism, during the surveillance of animal salmonelloses. Serotyping, known as the White-Kauffmann-Le Minor, scheme, has produced during the years a bulk of information contributing to conflicting opinions concerning the nomenclature and taxonomy of the genus Salmonella, thus needing constant revision of the rules managing it. Molecular methods are expected to steadily resolve these conflicts but they are yet far from replacing the existing system of naming and grouping Salmonella isolates. Thus, a concise summary of the existing scientific opinions and rules influencing still today the grouping of the genus Salmonella, could be useful to veterinarians and others working with the surveillance of animal salmonelloses.