The Occurrence of Antibiotic Resistance Genes in Taq Polymerases and a Decontamination Method Applied to the Detection of Genetically Modified Crops

Abstract

Different antibiotic resistance (AR) genes, such as Bla, Tet and NPTII, contaminate commercially available Taq polymerases. The specificity of the AR gene PCR can be increased when using a restriction enzyme-based decontamination of polymerase. The elimination of Taq polymerase contamination allows the use of PCR tests to screen seeds (corn) and processed food for the presence of genetically modified organisms (GMO) based on the detection of AR genes. Without a decontamination procedure for AR genes, PCR screening tests should be interpreted with caution.

Plasmid DNA contaminant in molecular reagents

“…In the studies analyzed, common antibiotic resistance gene sequences had been found from Enterobacter cloacae and Serratia marcesens . These two pathogens are increasingly resistant to multiple or most antimicrobial drug classes and the presence of resistance genes in clinical samples would not be surprising or questioned 14,15,17,45 . Consequently, the choice of antimicrobial treatment would be misguided towards reserve antimicrobials that are more toxic than standard ones.…”

“…Plasmids are naturally occurring circular shaped pieces of extrachromosomal DNA, which can replicate independently from the host DNA and can be transferred into samples via multiple routes 43,44 . Complete expression vector sequences have not been identified in commercially available enzyme preparations although fragments interfered occasionally with sequencing studies 14,15,17,41,42,45 . For example, Tenover et al ., had to use a native Taq polymerase to avoid false-positive test results when evaluating samples for the presence of antibiotic resistance genes such as Bla Tem-1 because most expression vectors used for generation of the enzyme also had this resistance gene 46 .…”

Nucleic acid amplification strategies facilitating the detection of genetically modified crop ingredients in foods

“…nptll) have been detected in com mercially available Taq polym erase preparations (prepared by recom binant D NA techniques) used in the PC R am plification process, and may therefore lead to false-positive reporting w hen screening for GM Os based on selectable m arker gene sequences such as n p tll (Perron et al, 2006) (Germini et al, 2005;Leimanis et al, 2006). M icroarray technology utilizes microscopic arrays o f oligonucleotide probes im m obilized on solid supports.…”