Molecular typing of Salmonella serotype Thompson strains isolated from human and animal sources

Abstract

One-hundred-and-thirteen isolates of Salmonella serotype Thompson from diverse sources in seven countries were characterized by PvuII ribotyping and IS200 fingerprinting. Ten PvuII ribotypes were observed. The predominant PvuII ribotype 1 represented a major clone of world-wide distribution but was not found in Australia; PvuII ribotypes 2 and 3 represented minor clones. HincII ribotyping discriminated subtypes within PvuII ribotype 1: HincII ribotype 1 was distributed widely but HincII ribotype 2 was found mainly in Scottish isolates. None of 101 isolates of PvuII ribotypes 1-3 contained copies of IS200. All 12 isolates of PvuII ribotypes 4-10 were from Australia and 7 of them contained copies of IS200 of 5 different profiles. These results suggest the existence of at least two lineages of Salmonella Thompson with a different geographical distribution. The finding that most isolates from man and poultry in Scotland belonged to the same ribotype (PvuII 1/HincII 2) and were IS200-negative suggests that poultry is an important source of human infection in Scotland.

Diversity of Strains of Salmonella enterica Serotype Enteritidis from English Poultry Farms Assessed by Multiple Genetic Fingerprinting

“…DNA typing techniques are now frequently used for epidemiological investigations, and the combination of conventional disease-tracing investigations and molecular epidemiology is yielding important insights into the epidemiology of many infectious diseases. Molecular epidemiology has been used to track specific strains of pathogens and to identify outbreaks of salmonellosis (4,6,10,20,23,34). The possibility for identification of sources of infection and routes of transmission strongly suggests that these new tools should be important components of surveillance programs.…”

Navigating Microbiological Food Safety in the Era of Whole-Genome Sequencing

“…Unlike PFGE, ribotyping uses a frequently cutting enzyme, but probe DNA is used to label certain bands, making them distinguishable (21). Variability in the number of rRNA genes, as well as size variability in the detected bands, leads to discrimination between bacterial strains.…”

Molecular Genetic Basis of Ribotyping

“…Rationales for the application of ribotype-based differentiation of independent isolates within a species have included taxonomic classification (25,46), epidemiological tracking (32,48,78,81), geographical distribution (14,32,81), and population biology and phylogeny (1,32,62,81). Such wide interest has led to the development of variant schemes from that initially described.…”