In addition to the inoculated strain, a total of 905 enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates recovered from experimentally infected cattle were analyzed by pulsed-field gel electrophoresis (PFGE). Twelve PFGE profiles were different from that of the inoculated strain. We successfully identified 5 distinct chromosomal deletions that affected the PFGE profiles by using wholegenome polymerase chain reaction (PCR) scanning and DNA sequencing analysis. The changes in the PFGE profiles of EHEC O157:H7 isolates after passing through the intestinal tract of cattle were partly generated by deletions in the chromosomal regions.
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Reference:
Yoshii, N. et al. (2009) Appl. Environ. Microbiol. 75 (17):5719-5726.
