Use of macroporous polypropylene filter to allow identification of bacteria by PCR in human fecal samples

The detection of pathogenic bacteria directly in human fecal specimens by P CR, requires removal of PCR-inhibitory substances. To investigate whether f ive different macroporous filters (polypropylene, nylon, polyester, polyeth ylene, fluorocarbon) could retain polysaccharides, major PCR inhibitors, an in vitro model and human fecal samples were used. The in vitro model consi sted of Xanthum gum solutions (3 mg/ml PBS), a bacterial polysaccharide, to which Helicobacter pylori cells were added. Fecal samples from healthy vol unteers were spiked with H. pylori and Mycobacterium paratuberculosis cells . Polysaccharide concentrations were significantly reduced only by the poly propylene but not by the other filters. Accordingly, both Xanthum gum solut ions and spiked fecal specimens became PCR positive only after filtration w ith the polypropylene filter. We conclude that this filter can be used to p repare a bacterial DNA template suitable for PCR analysis from human feces. (C) 2000 Elsevier Science B.V. All rights reserved.