CONSTRUCTION OF A SPECIES-SPECIFIC DNA OLIGONUCLEOTIDE PROBE FOR STREPTOCOCCUS-THERMOPHILUS ON THE BASIS OF A CHROMOSOMAL LACZ GENE

On the basis of the DNA nucleotide sequence of the chromosomally located lacZ gene of Streptococcus thermophilus a species-specific DNA-oligonucleotide probe was synthesized. The probe was derived from a region of low similarity among the so far known lacZ genes from other bacteria (Lactobacillus delbrueckii subsp. bulgaricus, Escherichia coli, Klebsiella pneumoniae, Clostridium acetobutylicum). Using DNA hybridization this probe allows a quick identification of this species in fermented milk products.