Direct in Gel Genomic Detection of Antibiotic Resistance Genes in S1 Pulsed Field Electrophoresis Gels.

S1 pulsed field gel electrophoresis (PFGE) is a method to separate the bacterial chromosome(s) from plasmid nucleic acids. When combined with ethidium bromide staining and UV visualization this method is excellent at assessing the number of plasmids in individual bacterial strains. It is also good at approximating the true size of each individual plasmid when run against a DNA molecular marker. However, downstream applications such as: the location of individual resistance genes on individual plasmids or the chromosome are hampered by very poor transfer of large DNA molecules from agarose gels to adsorbent nylon or nitrocellulose membranes. Herein, we describe a method to directly probe agarose PFGE gels eliminating the necessity of transfer and generating excellent genomic location results.