Comparison of Streptococcus thermophilus strains by pulse field gel electrophoresis of genomic DNA

Abstract

Pulse field gel electrophoresis (PFGE) was utilised to compare the genomes of 16 Streptococcus thermophilus cultures from yoghurt, cheese, laban and dahi after digestion with the restriction endonucleases, SfiI, SmaI and BssHII. PFGE profiles could be used for strain identification and were also useful in predicting relatedness of certain strains. Genetic variations between specific morphotypes of a highly proteolytic culture were not detectable by PFGE in this study. Statistical analysis of SmaI restriction patterns enabled the clustering of strains into two groups which corresponded with biochemical properties of the strains examined and suggested that PFGE profiles could be useful in predicting biochemical characteristics. z 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

Genetic diversity in Swiss cheese starter cultures assessed by pulsed field gel electrophoresis and arbitrarily primed PCR

“…helveticus clusters II and III contained only strains of the same acid production phenotype, but otherwise the clusters contained two or more phenotypes. O'Sullivan and Fitzgerald (1998) were able to associate acid production with two clusters of Strep. thermophilus .…”

“…The similarities reported here are consistent with those observed by authors investigating the same species with PFGE. O'Sullivan and Fitzgerald (1998) analysed Sma I genomic digestions by PFGE and found 39·53% similarity among 16 Strep. thermophilus strains.…”

Survival of Yogurt Bacteria in the Human Gut

“…Isolates that were confirmed to be S. thermophilus isolates were then analyzed by pulsed-field gel electrophoresis (PFGE) because of the lack of reliable PCR primers that could distinguish between the closely related species S. thermophilus and Streptococcus salivarius present in human oral cavity (28,34). Profiles of SmaI-digested chromosomes, obtained as described by O'Sullivan and Fitzgerald (25), were compared in order to determine strain identities.…”

Characterisation of Streptococcus thermophilus CNRZ1205 and its cured and re-lysogenised derivatives

“…The ¢rst of which was to determine if the clumping phenotype was due to a large genetic re-arrangement which may have occurred as a consequence of the mitomycin C treatment. SmaI was chosen as a suitable enzyme for digestion of the DNA because work by Roussel et al [1] and O'Sullivan and Fitzgerald [2] had shown that restriction of S. thermophilus chromosomal DNA with SmaI resulted in 14^15 fragments greater than 30 kb. The numbers of genomic restriction fragments generated in S. thermophilus CNRZ1205 and its cured and re-lysogenised derivatives by SmaI appear to be less than those reported by other researchers [1,2] (Fig.…”