Use of the molecular typing methods to evaluate the control of Listeria monocytogenes contamination in a raw milk and dairy products.

Nineteen serogroup 1/2a Listeria monocytogenes strains isolated from raw milk, dairy products and salt water in one dairy were analyzed. Pulsed field gel electrophoresis (PFGE) and ribotyping were used to determine whether these strains isolated over a 8-month period are epidemiologically related. The samples of raw milk were contaminated by different L.

[Factors and genetics of pathogenicity of group B Streptococci].

In this review data on the pathogenicity factors of streptococci and their genetic control are presented. Attention is paid mainly to protein antigens alpha and beta, C5a peptidase, CAMP factor, R, Rib and X proteins. The problems of making the genetic and physical charts of the genome of group B streptococci, the genetic regulation of the synthesis of pathogenicity factors and the specific features of the damaging action of the infective agent are discussed.

Comparative genetic study of group B streptococcal strains of human and bovine origin.

The presence and restriction fragment length polymorphism (RFLP) of DNA fragments hybridizing with virulence and "house keeping" gene probes were analyzed for 87 group B streptococcal (GBS) strains of human and bovine origin. Most characteristics obtained for bovine strains were similar when compared with those for human strains. The most significant degree of RFLP was discovered for the sizes of HindIII fragments containing bca gene.