MOLECULAR EPIDEMIOLOGY OF CORYNEBACTERIUM-DIPHTHERIAE FROM NORTHWESTERN RUSSIA AND SURROUNDING COUNTRIES STUDIED BY USING RIBOTYPING AND PULSED-FIELD GEL-ELECTROPHORESIS

A selection of 100 Corynebacterium diphtheriae isolates from asymptoma tic carriers and clinical cases from five regions in northwestern Russ ia were examined, Six additional isolates from patients in Finland and Estonia with epidemiological links to Russia were also examined. All isolates were characterized by biotyping, toxigenicity testing, riboty ping, and pulsed-field gel electrophoresis (PFGE), Hybridization of ge nomic DNA digested with BstEII revealed five ribotype patterns among t he biotype gravis isolates (G1 through G5) and two patterns among the biotype mitis isolates (M1 and M2), PFGE using SfiI was not able to di stinguish between ribotypes G1, G2, and G4, The predominant ribotype p attern, G1, found in cases of disease in all the areas studied, appear s to be disseminating, in view of the isolates received from imported cases in Finland and Estonia, Among the 106 isolates examined, 68 prod uced pattern G1 and 24 produced pattern M1, Most of the M1 isolates we re from the Leningrad Oblast region, Distinct ribotypes such as G2, G3 , G4, G5, and M2 could represent endemic disease.