Magnetic non-porous hydrophilic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate)-P(HEMA-co-GMA) microspheres containing carboxyl groups were used for DNA isolation from mouse faeces spiked by a probiotic Lactobacillus gasseri K7 strain. The quality of isolated DNA and the presence of target DNA were verified by PCR and real time PCR using primers specific for Lactobacillus genus or primers targeting gassericin A gene of the Lactobacillus gasseri K7 strain. For comparison, two other DNA extraction procedures were used. It was shown that DNA extracted by carboxyl-coated P(HEMA-co-GMA) microspheres were sufficient for the amplification of target DNA using PCR and real-time PCR.