PROTEIN FINGERPRINTING AS A HELPFUL TOOL FOR INTRA-SPECIFIC DIFFERENTIATION OF BIOTECHNOLOGICALLY USED LACTOBACILLUS - STRAINS AND CLINICALISOLATES

Lactobacilli are often used in products of animal origin because of th eir technological properties and as protective cultures against pathog enic microorganisms, however they are supposed to be related to human infections as well. Therefore 39 strains of species that are in biotec hnological usage, including the type strains, and some clinical isolat es were investigated. 9 strains of L. acidophilus, 7 of L. gasseri and 23 strains of L. rhamnosus were tested. Biochemical and physiological properties were proved by classical tests. Analysis of the total solu ble cytoplasmatic protein patterns was performed with diamine silver s taining, a technique not previously applied to lactobacilli. Classical tests were able to confirm all strains as belonging to one of the thr ee species. Analysis of protein patterns allowed to differentiate betw een strains of the same species. In case of L. acidophilus biotechnolo gically used strains and clinical isolates were clustered separately. L. rhamnosus formed three clusters. SDS-PAGE of proteins together with diamine silver staining seems to be helpful to detect intra-species d ifferences. It was stated, that technologically used strains of lactob acilli could clearly be differentiated from another and also from clin ical isolates.