POLYMERASE CHAIN-REACTION FOR THE SPECIFIC DETECTION OF ESCHERICHIA-COLI SHIGELLA

The outer membrane protein PhoE of members of the family Enterobacteri aceae consists of conserved membrane-spanning segments and hypervariab le surface-exposed regions. Two oligonucleotides based on DNA sequence s encoding two different cell-surface-exposed regions of the Escherich ia coli K12 PhoE protein were tested for their specificity in polymera se chain reactions. They reacted with all strains of the species E. co li/Shigella tested, except for strain S. boydii serovar 13, which is k nown to represent a different DNA-relatedness group. The probes did no t react with any other Enterobacteriaceae tested, including strains of Escherichia blattae, Escherichia hermannii, Escherichia vulneris and Escherichia adecarboxylata, except for an Escherichia fergusonnii stra in, which is most closely related to E. coli. Therefore, the primer co uple showed a high degree of species-specificity. In addition, a secon d primer couple based on two conserved regions of the phoE genes was t ested. This primer couple recognized a broad group of closely related enteric bacteria including Salmonella and Shigella.