GENOTYPIC AND PHENOTYPIC DETERMINATION OF 5 VIRULENCE MARKERS IN CLINICAL ISOLATES OF ESCHERICHIA-COLI

The presence of the virulence markers K1 capsule, serum resistance, ae robactin, S and P/PR fimbriae were examined in a total of 395 E. coli strains from different extraintestinal infections and in 81 faecal iso lates of healthy volunteers using specific DNA probes and classical ph enotypic methods. All markers were more frequently detected when genot ypic assays were applied. The simultaneous occurrence of 3-4 virulence determinants was typical for isolates derived from patients with sept icaemia or meningitis. Isolates from blood cultures and cerebrospinal fluid were expressing the virulence phenotypes to a greater extent tha n isolates from urine or faeces. The use of colony hybridization with specific oligonucleotide and polynucleotide probes for the detection o f virulence determinants has been proven to be more specific and relia ble than phenotypic approaches.