Studies On Gene Transformation Techniques For Klebsiella Pneumoniae

The proposed methods for Klebsiella pneumoniae transformation with exogenous DNA are the same as those for Esherichia coli, i.e., bacterial cells cultured in liquid medium are electrotransformed with plasmids. Although several reports claimed that extremely efficient transformation could be obtained if the medium contain EDTA, EGTA, or other chelate agents, few investigators cited their reports during the past decade. Our experience demonstrated that only 103 clones could be generated with one microgram of plasmid. Such transformation efficiencies would limit molecular research of Klebsiella pneumoniae.It is believed that capsule of Klebsiella pneumoniae is too thick to be punched electronically or chemically. Additionally, thickening capsule will decrease specific gravity of bacteria so that it is difficult to retrieve bacterial cells by centrifugation.Our results indicated that transformation efficiency of capsule deficient mutant Mag A- is 1-2 magnitude higher than wild type, demonstrating the capsule is actually one of barriers for high efficient transformation. However the transformation efficiency of mutant Mag A- is still much lower than Esherichia coli, suggesting there should be other factors that inhibit Klebsiella pneumonia transformation.We determined the transformation efficiencies of Klebsiella pneumonia cultured on solid medium. It is surprised that at least 3 magnitudes higher efficiencies could be obtained compared with the bacteria from liquid culture.