Genotypes and phylogenetic relationships of Salmonella typhimurium are defined by molecular fingerprinting of IS200 and 16S rrn loci

Abstract

Molecular fingerprints of chromosomal genotypes in Salmonella typhimurium were generated by analysis of variation at the 16s vrn gene loci and the sites of the insertion sequence IS200. Genetic and reference strains of S. typhimuvium were compared with clinical phage type strains from cases of human salmonellosis. Three 1 6 s rrn profiles, one of which was predominant, were found. The copy number of the SaZmonelZa-specific insertion sequence IS200 varied from 6 to 12, and all insertions were chromosomal. Three of the insertion sites shared by all strains were serovar-specific for S. typhimurium. Thirteen distinct profiles of IS200 were detected, providing a high level of intraserovar strain discrimination. Profiles were generally more conserved among genetic and reference strains ; representatives of clinical phage type strains, which are recent human isolates, showed much greater diversity of IS200 profiles. Irrespective of their origin, strains could be assigned to IS200 profile groups, phylogenetically related lines identified by combinations of conserved insertion sites. Hybridization profiles of this mobile element are markers of intermediate and short-term evolution in S. typhimuvium. They provide a fingerprinting scheme for the purposes of genetics, and delineate a molecular typing scheme for the purposes of epidemiology.

Molecular typing of Salmonella enterica subsp. enterica serovar Enteritidis isolates

“…This method was particularly helpful for serovars that usually harboured a large number of IS200 copies such as Typhimurium [15,29], Typhi [39], Paratyphi [40], Java [40] and Heidelberg [36]. In other serovars, such as Berta [37,38] and Enteritidis , its use for epidemiological typing was limited due to the low number of IS200 copies in these strains.…”

“…Traditional epidemiological studies included biochemical and serological characteristics of the Genotypic analysis of salmonellae by molecular typing methods has proved to be helpful in the characterisation of strains from different Salmonella serovars, such as S. Typhimurium [6,15,27,29], S. Enteritidis [6, 9-11,30-331, S. Dublin [24,34], S. Virchow [35], S. Heidelberg [36], S. Berta [37,38], S. Typhi [39], S. Paratyphi [40] and S. Java [40]. The techniques included plasmid analysis, ribotyping, IS200 typing and PFGE analysis.…”

Application of ribotyping and IS200 fingerprinting to distinguish the five Salmonella serotype O6,7[ratio ]c[ratio ]1,5 groups: Choleraesuis sensu stricto, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C, and Typhisuis

“…Primers utilized for amplification of IS200 sequence were identical to those designed by Bisercic and Ochman (forward 5h-CAGATGCGCCTATAAGG-CT-3h and reverse, 5h-CTAGGCTGGGGGTTCCG-GAA-3h) [10]. An internal fragment of the 16S rrn gene was amplified by use of primers 5h-GCAACG-CGAAGAACCTTACC-3h and 5h-GGTTACCTTG-TTACGACTT-3h [11]. The expected amplicon sizes for the two pairs of primers were 660 bp and 550 bp respectively ; both lack PvuII and PstI restriction sites.…”

Insertion element IS 1296 in Mycoplasma mycoides subsp. mycoides small colony identifies a European clonal line distinct from African and Australian strains

“…mjcoides SC was the first mycoplasma to be isolated (Nocard & ROUX, 1898), and that it is an important contagious pathogen, little is known about this organism. So far, the size and a physical map of the chromosome of the type strain PG1 has been established (Pyle et al, 1990), and methods for species identification and detection have been developed based on PCR amplification of DNA segments of unknown function (Bashiruddin et al, 1994a, b;Dedieu e t al., 1994) et al, 1994) and for Salmonella (Stanley et al, 1993). The insertion sequence IS 1276, recently identified in subsp.…”