Vol. 45, No. 2, 2001 content next

FEATURES OF THE GENOME STRUCTURE OF GROUP B STREPTOCOCCI OF BOVINE ORIGIN

Dmitriev, A.a, Totolian, A.a*, Tkáčiková, L.b, Mikula, I.b

a Institute of Experimental Medicine
acad. Pavlov's str., 12
Saint Petersburg, 197376
Russia		 b University of Veterinary Medicine
Komenského 73
Košice, 04181
The Slovak Republic		 * - corresponding author

Summary

A collection of 35 Streptococcus agalactiae (GBS) strains of bovine origin was analysed by pulsed-field gel electrophoresis, DNA-DNA hybridization, and PCR in order to evaluate the genetic types and genome organization of animal group B streptococci (GBS) strains. Three genetic types (bca+ scpB+ bac-, bca+ scpB- bac-, and bca- scpB- bac- ) were revealed among bovine GBS strains and only one of them (bca+ scpB+ bac-) was found among human GBS strains. The presence of scpB gene only in a few GBS strains of bovine origin as well as an absence of bac gene in bovine strains are two most informative criteria for differentiation of bovine GBS strains from human strains.
The molecular size of the entire bovine GBS chromosome varied from 2191 kb to 2465 kb as determined by pulsed-field gel electrophoresis. The high degree of heterogeneity of SmaI fragments of 100 kb and smaller was determined which resulted in 21 SmaI restriction patterns for the 35 strains tested. It was found out that the genome sizes of some genetically related strains were different by several kilobases only. One of the differences was found to be associated with the deletion or insertion of scpB gene.
These results demonstrated that bovine GBS strains could probably lose or accept the parts of the genome due to some kind of genetic rearrangements. However, the preliminary analysis of the entire genome organization of bovine GBS strains demonstrated its similarity to the genome organization of GBS strains isolated from humans.

Key words: genetic typing; genome organization; Streptococcus agalactiae

References

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Folia Veterinaria / 2001