High-frequency secondary mutations after suicide-driven allelic exchange mutagenesis in extraintestinal pathogenic Escherichia coli.
Frequent unintended secondary mutations occurred in extraintestinal pathogenic Escherichia coli strains CP9, CFT073, and RS218 during suicide plasmid-mediated, putatively specific deletions of hlyA, papG allele III, and iha. Pulsed-field gel electrophoresis and PCR analyses demonstrated genomic alterations and/or unintended loss of defined virulence genes (papG, the F7-2 papA allele, iutA, sat, hlyD, and cnf). Caution is warranted when attributing the observed phenotypic changes to the intended mutation.
Johnson
James R
JR
Mucosal and Vaccine Research Center, Infectious Diseases (111F), Veterans Affairs Medical Center, One Veterans Drive, Minneapolis, MN 55417, USA. johns007@umn.edu
Lockman
Hank A
HA
Owens
Krista
K
Jelacic
Srdjan
S
Tarr
Phillip I
PI
D000483:Alleles; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D017353:Gene Deletion; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D014774:Virulence / Q000235:genetics