Structure and function of plasmid pColD157 of enterohemorrhagic Escherichia coli O157 and its distribution among strains from patients with diarrhea and hemolytic-uremic syndrome.
In this study, pColD157, a 6.7-kb colicinogenic plasmid of enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain CL40cu, was characterized by restriction mapping and determination of its complete nucleotide sequence. The sequence consists of 6,675 bp and shows a high degree of similarity to the nucleotide sequence of colicinogenic plasmids pColD-CA23 and pColK. Seven potential genes were located on pColD157, three of which were closely related (>97.9%) to the colicin D structural gene and the corresponding immunity and lysis genes of plasmid pColD-CA23, and these were therefore designated cda, cdi, and cdl, respectively, using the reference extension -CL40 for differentiation. The adjacent 3' region is related to the origin of replication of pColD-CA23. In contrast, the remaining part of the plasmid harbors a cluster of genes, closely related to the mobilization genes of pColK, which is followed by a 0.3-kb stretch homologous to the pColK resolution function. These determinants were designated mbdA, mbdB, mbdC, and mbdD and cdr, respectively. Southern blot analysis was performed with a probe specific for the cda gene of pColD157 and two groups of EHEC O157:H7 isolates from patients with diarrhea or hemolytic-uremic syndrome resident in Germany. Whereas 16 of 46 E. coli O157 strains isolated between 1987 and 1991 harbored plasmid pColD157, only 1 of 50 strains isolated during 1996 carried this plasmid. In addition, all strains harboring plasmid pColD157 were shown to have colicinogenic activity.
Hofinger
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Institut für Hygiene und Mikrobiologie der Universität Würzburg, Germany.
Karch
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Schmidt
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D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D003087:Colicins / Q000096:biosynthesis; D004269:DNA, Bacterial / Q000737:chemistry; D003967:Diarrhea / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000235:genetics*; D006463:Hemolytic-Uremic Syndrome / Q000382:microbiology*; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids
D003087:Colicins; D004269:DNA, Bacterial