Elimination of contaminating DNA within polymerase chain reaction reagents: implications for a general approach to detection of uncultured pathogens.

Analysis based on comparisons of 16S rRNA sequences provides a rapid and reliable approach to identifying human pathogens. By directing oligonucleotide primers at sequences conserved throughout the eubacterial kingdom, bacterial 16S ribosomal DNA sequences of virtually any member of the eubacterial kingdom can be amplified by polymerase chain reaction and subsequently analyzed by sequence determination. Indeed, automated systems for broad-range amplification, sequencing, and data analysis are now feasible and may form the basis of the next generation of automated microbial identification systems. However, identification of pathogens by this strategy is hampered by the frequent contamination of reagents used for the amplification reaction, in particular Taq polymerase, with exogenous bacterial DNA. Here, we describe detailed investigations on the use of 8-methoxypsoralen and long-wave UV light to eliminate contaminating DNA in polymerase chain reaction reagents. The clinical utility of the developed procedure was demonstrated in a case of paucibacillary osteomyelitis, for which no specific bacterial agent had been cultured.